Has there been the least indication yet when we are too get some more results in relation to those who are experimenting in this area?
Well, looking at the thermistor data with the PZT stack mach effect thruster, whatever it's doing doesn't look like a transient thermal effect...
That is a very interesting paper. Very clean results compared to previous presentations and the Hoyl and Narliker approach to theory looks promising. It needs to be emphasised that this is an ME device, not EM, and that the paper reports that the theory is a work in progress.
"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.
Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.
Notice that the force per power input reported by Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives". Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:
reported measurement ForcePerPowerInput (milliNewtons/kW)
(* Cannae Superconducting *) 761.9 to 952.4
(* Shawyer Demo *) 80 to 243
(* Shawyer Experimental *) 18.82
(* Brady c TE mode *) 21.31
(* Brady a TM mode*) 5.396
(* Brady b TM mode*) 3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176
lengths in meter
rfFrequency in 1/second (microwave frequency during test)
power in watts
force in milliNewtons
force per PowerInput in milliNewtons/kW
c= 299705000 m/s (speed of light in air)
c= 299792458 m/s (speed of light in vacuum) (for Cannae Superconducting)
(the difference between c in air compared to c in vacuum is negligible)
Note: SmallDiameter for Shawyer's EM Drives obtained from his reported ShawyerDesignFactor .
Force/PowerInput of a Photon Rocket = 1 / c
(* Cannae Superconducting *)
rfFrequency = 1.047*10^9;
cavityLength = 0.01+0.004+0.006+0.01 = 0.03;
bigDiameter =(22.86-2*(0.00430)) = 0.220;
smallDiameter = bigDiameter-2*0.01=0.200;
power = 10.5
Q = 1.1*(10^7)
measured force = 8 to 10
measured ForcePerPowerInput = 761.9 to 952.4
Force/PowerInput of a Photon Rocket =0.003336
measured ForcePerPowerInput to the one of a photon rocket = 228,400 to 285,500
(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;
bigDiameter=0.16;
smallDiameter=0.127546;
power = 850
Q = 5900
measured force = 16
measured ForcePerPowerInput = 18.82
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =5,640
(* Shawyer Demo *)
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
All Brady cases have the following dimensions:
cavityLength=0.332;
bigDiameter=0.397;
smallDiameter=0.244;
(* Brady a TM mode*)
rfFrequency=1.9326*10^9;
power = 16.9
Q = 7320
measured force = 0.0912
measured ForcePerPowerInput = 5.396
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =1,617.2
(* Brady b TM mode*)
rfFrequency=1.9367*10^9;
power = 16.7
Q = 18100
measured force = 0.0501
measured ForcePerPowerInput = 3.000
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =899.12
(* Brady c TE mode *)
rfFrequency = 1.8804*10^9;
power = 2.6
Q = 22000
measured force = 0.05541
measured ForcePerPowerInput = 21.31
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =6,386.7
(* Fearn, Zachar, Woodward & Wanser*)
rfFrequency = 39,300;
power = 170
measured force = 0.002
measured ForcePerPowerInput = 0.01176
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 3.526
I'm glad to see the discussion continued in this thread. I must admit, I felt disappointed at the prospect of losing this resource and the small band of interested theorists and experimentalists exploring what may appear to be the impossible, but which may ultimately result in profound space flight applications.Can I just thank you for providing that link as it appears to be a good source of information on this topic.
Might I suggest, that if this forum turns out not to be the right place in the future (e.g., if the thread is removed again), that all those who maintain an interest in the topic to congregate in the http://www.reddit.com/r/emdrive forum. In fact, I suggest that you bookmark that page now for future reference.
I too do not appreciate personal attacks, which have no place in this kind of discussion, and so I understand the desire to keep the thread clean. On the other hand, this topic is too important not to keep alive.
"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.
Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.
Notice that the force per power input reported by Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives". Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:
reported measurement ForcePerPowerInput (milliNewtons/kW)
(* Cannae Superconducting *) 761.9 to 952.4
(* Shawyer Demo *) 80 to 243
(* Shawyer Experimental *) 18.82
(* Brady c TE mode *) 21.31
(* Brady a TM mode*) 5.396
(* Brady b TM mode*) 3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176
...
....It's great to have you posting again here, Frobnicat, as your always thoughtfully scientific and frobnicating posts have been one of the main attractions of this thread.
While I was sceptic and still am, I learned a lot of interesting things from the previous thread, and enjoyed it even with itsdefaults.
May I suggest that people interested in "Mach effect" (reality of which having obvious consequences on directions advanced spaceflight can take) contribute on a thread with a more appropriate explicit topic (and historical content) : Propellantless Field Propulsion and application. The risk in splitting the somewhat frozen propellantless discussion of late would be to make it even harder to revive some activity, but EM and ME approaches are two very different kind of theories and devices, interwining of both topic discussion in a single thread was one of the reason of the chaos that plagued the 1st EM drive thread.
Anyhow, for those interested in Mach effect, here are two versions of results from attempt of Woodward (2008...) at "proof of effect" exhumed from Propellantless thread:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260412
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260481
Haven't read in detail yet.
I won't crosspost here my posts about that (if I have the courage to address some of it deeper)
http://forum.nasaspaceflight.com/index.php?topic=13020.msg1304798#msg1304798
May I suggest that people interested in "Mach effect" (reality of which having obvious consequences on directions advanced spaceflight can take) contribute on a thread with a more appropriate explicit topic (and historical content) : Propellantless Field Propulsion and application. The risk in splitting the somewhat frozen propellantless discussion of late would be to make it even harder to revive some activity, but EM and ME approaches are two very different kind of theories and devices, interwining of both topic discussion in a single thread was one of the reason of the chaos that plagued the 1st EM drive thread.
Anyhow, for those interested in Mach effect, here are two versions of results from attempt of Woodward (2008...) at "proof of effect" exhumed from Propellantless thread:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260412
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260481
Haven't read in detail yet.
I won't crosspost here my posts about that (if I have the courage to address some of it deeper)
http://forum.nasaspaceflight.com/index.php?topic=13020.msg1304798#msg1304798
Good points, frobnicat, besides the PropellantLess thread:
http://forum.nasaspaceflight.com/index.php?topic=13020.0
the Woodward effect fans have had their own threads @ NASASpaceFlight, for example this one, completely dedicated to the Woodward effect:
http://forum.nasaspaceflight.com/index.php?topic=31037.0
The reported "thrust" force/(power input) of the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) is about 2000 times less than the NASA Brady et.al TE mode and about 20,000 times less than the Shawyer Demo
In other words, it takes (for the latest Woodward experiments) 3 to 4 orders of magnitude greater input power to produce the same level of what is reported as "thrust" force
The reported "thrust" force/(power input) of the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) is about 2000 times less than the NASA Brady et.al TE mode and about 20,000 times less than the Shawyer Demo
In other words, it takes (for the latest Woodward experiments) 3 to 4 orders of magnitude greater input power to produce the same level of what is reported as "thrust" force
Why does this matter? I was under the impression that while both lines of inquiry hold incredible promise. They still require more research and testing to get to the point where a wider audience would be willing to accept them.
focus on space flight applications to ensure this can have a healthy home here.
The reported "thrust" force/(power input) of the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) is about 2000 times less than the NASA Brady et.al TE mode and about 20,000 times less than the Shawyer Demo
In other words, it takes (for the latest Woodward experiments) 3 to 4 orders of magnitude greater input power to produce the same level of what is reported as "thrust" force
Why does this matter? I was under the impression that while both lines of inquiry hold incredible promise. They still require more research and testing to get to the point where a wider audience would be willing to accept them.
As Chris Bergin made clear, the purpose of this forum is to deal with SPACEFLIGHT APPLICATIONS (of EM Drives: those propellantless drives comprised of a microwave cavity as the devices tested by Shawyer in the UK, Prof. Juan Yang in China and Brady, March, White, et.al. at NASA):Quote from: Chris Bergifocus on space flight applications to ensure this can have a healthy home here.
It matters because the amount of power required to produce a given level of thrust is of vital importance for spaceflight applications.
The fact that the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) show that it takes 20,000 times more power to produce a given level of thrust than the power required to produce the same thrust for the EM Drive (Shawyer demo) is extremely important for spaceflight applications.
The reported "thrust" force/(power input) of the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) is about 2000 times less than the NASA Brady et.al TE mode and about 20,000 times less than the Shawyer Demo
In other words, it takes (for the latest Woodward experiments) 3 to 4 orders of magnitude greater input power to produce the same level of what is reported as "thrust" force
Why does this matter? I was under the impression that while both lines of inquiry hold incredible promise. They still require more research and testing to get to the point where a wider audience would be willing to accept them.
As Chris Bergin made clear, the purpose of this forum is to deal with SPACEFLIGHT APPLICATIONS (of EM Drives: those propellantless drives comprised of a microwave cavity as the devices tested by Shawyer in the UK, Prof. Juan Yang in China and Brady, March, White, et.al. at NASA):Quote from: Chris Bergifocus on space flight applications to ensure this can have a healthy home here.
It matters because the amount of power required to produce a given level of thrust is of vital importance for spaceflight applications.
The fact that the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) show that it takes 20,000 times more power to produce a given level of thrust than the power required to produce the same thrust for the EM Drive (Shawyer demo) is extremely important for spaceflight applications.
focus on space flight applications to ensure this can have a healthy home here.
May I suggest that people interested in "Mach effect" (reality of which having obvious consequences on directions advanced spaceflight can take) contribute on a thread with a more appropriate explicit topic (and historical content) :>> << As reminded by managing editor, NSF is about space flight. Given the turn taken by the thread, the admin intervention is quite understandable, and most of the content wasn't thrashed, thanks. While the "space drives" in general are on topic here if proven, the reality of any effect at all (and with what possible backing theories) is still controversial, and this open question is more a matter of fundamental science and has interest in and by itself beyond space flight. Since discussing those theoretical and experimental aspects are only marginally appropriate on this forum then that could proceed "preemptively" at other more appropriate place. Otherwise some talks will be rather contrived ( how make comment sound "space flight relevant" while it's not directly )
After carrying out a variety of experiments designed to exploit the presumed existence of Mach effects to produce small thrusts that yielded varying results, the decision was taken to carry out an experiment to test for the existence of such effects in the simplest of all possible circumstances. The aim was to settle the question of the existence the effects. Underlying physics suggests that these effects should exist; but in some experiments the effects expected were either not present, or much smaller than predicted. Without experimental evidence that the predicted Mach effects in fact do exist, situations in which they are small or not present may be taken as evidence that Mach effects do not exist.
...That said since you also wrote a critique of the Eagle Works test showing that the results could be thermal effects I would think the Thrust figures of either EM Drives or MET thrusters would be consider as simply a measure of how far both approaches have to go to be useful. It could be that a large part of the EM Drive thrust numbers are thermal and will be reduced when tested in vacuum. ...
It could be that a large part of the EM Drive thrust numbers are thermal and will be reduced when tested in vacuum.
Some things don't scale - Woodward is one. Another with a much better chance is the Sagnac effect, the only challenge is getting anything useful out of them. At a larger scale it would be awesome if Stirling engines would scale.
EmDrive will stay in the lab
First, thanks to Chris for opening this new thread.ASRG is advanced Stirling radioisotope generator. It is purposed to generate more power than the traditional RTG at the cost of having moving parts.
That said, some definitions might be in order to avoid confusion.
Stirling Engine: The version I am familiar with is proven old line technology, essentially a temperature difference engine. I have seen DIY versions on You-Tube and elsewhere, and read of others that can act as low power solar generators, but have no idea how this might pertain to spaceflight. What is 'ASRG?'
Sagnac effect. I have not heard of this before.
...the system of EM wave and waveguide can be regarded as an open system, with the EM wave and the waveguide having separate frames of reference.
A similar approach is necessary to explain the principle of the laser gyroscope, where open system attitude information is obtained from an apparently closed system device.
There is a description of the Sagnac effect on wikipedia, this is the basis of a laser gyroscope. Interestingly Newtonian physics and relativity give the same answer for this. I isn't related to the microwave drive. I think they mention it because laser gyroscopes are conceptually complicated and they hope that the reader won't understand them, and therefor not understand that if anything they are yet more evidence that this trick doesn't work.Uncorrected for spelling. The comment is about another post musing about the last sentence of emdrive.com principle page about laser gyroscope.
There is some similarity of the EMDrive to the Sagnac oscillator if the optical fiber has a linear variation in the index of refraction. The frames of reference are stationary and accelerating rather than constant velocity. But, I havn't seen any reference or calculation giving rotary forces as yet. At the moment I'm chasing old photon to graviton papers.
There is some similarity of the EMDrive to the Sagnac oscillator if the optical fiber has a linear variation in the index of refraction. The frames of reference are stationary and accelerating rather than constant velocity. But, I havn't seen any reference or calculation giving rotary forces as yet. At the moment I'm chasing old photon to graviton papers.
The Sagnac effect compares the (rotating) velocity frame of reference in which the opposing photons show the same frequency w/ the (stationary) frame in which the doppler photons are observed.
The Shawyer cavity photons can be compared in the (stationary) dispersion frame w/ the same frequency and in an (accelerated) frame which balances out the dispersion and expresses the doppler shifts.
Post admits in his great review article: “The search for a physically meaningful transformation for rotation(parenthesis and bold added for explanatory purposes)
is not aided in any way whatever by the principle of general space-time covariance (relativity), nor is it true that the space-time theory of gravitation (general relativity) plays any role in establishing physically correct transformations (relevant to the Sagnac effect).”
In 1925 Michelson and Gale built a huge earth-fixed Sagnac Interferometer in Illinois demonstrating that the light velocity is anisotropic on the rotating earth. For Sagnac this result did not come as a surprise having explained the underlying effect on the basis of the ether theory in 1913. The Special Relativity Theory (SRT), however, had predicted on the basis of the Lorentz Transformation (LT) that the velocity of light is isotropic in all inertial systems
http://www.mehtapress.com/mehtapress/Journals/Journal-of-Space-Exploration/Volume-3-Issue-1/vol_3_issue_1_file_2.pdf
I'm not qualified to judge the space flight applicability of the above article by Dr. Woodward as it pertains to this forum. A brief history, theory and recent experiments are detailed. It also contains a critique of quantum vacuum explanations for emdrive propulsion. Just thought I should bring it to this groups attention and I'll return to lurking. I've passively appreciated this discussion for a long time. Some of the most contentious moments have been the most educational. I'll miss the perspectives of Ron Stahl and Mullertron assuming they don't return. Thanks to everyone who has contributed. Truly fascinating.
the purpose of this forum is to deal with SPACEFLIGHT APPLICATIONS (of EM Drives: those propellantless drives comprised of a microwave cavity as the devices tested by Shawyer in the UK, Prof. Juan Yang in China and Brady, March, White, et.al. at NASA)
...
and therefore these experiments do not constitute "EM Drive Spaceflight Applications" (as instructed by Chris Bergin) Woodward fans persist on carrying a debate on this thread rather than their own Woodward thread.
Frankly, I don't understand what is the goal being pursued here by Woodward-effect fans to insist to carry arguments concerning Woodward's theory and experiments in this thread.
There is some similarity of the EMDrive to the Sagnac oscillator if the optical fiber has a linear variation in the index of refraction. The frames of reference are stationary and accelerating rather than constant velocity. But, I havn't seen any reference or calculation giving rotary forces as yet. At the moment I'm chasing old photon to graviton papers.
The Sagnac effect compares the (rotating) velocity frame of reference in which the opposing photons show the same frequency w/ the (stationary) frame in which the doppler photons are observed.
The Shawyer cavity photons can be compared in the (stationary) dispersion frame w/ the same frequency and in an (accelerated) frame which balances out the dispersion and expresses the doppler shifts.
A classic (1967, Air Force Cambridge Research Lab , Massachusetts) article on the Sagnac effect, by Post:
http://www.orgonelab.org/EtherDrift/Post1967.pdfQuotePost admits in his great review article: “The search for a physically meaningful transformation for rotation(parenthesis and bold added for explanatory purposes)
is not aided in any way whatever by the principle of general space-time covariance (relativity), nor is it true that the space-time theory of gravitation (general relativity) plays any role in establishing physically correct transformations (relevant to the Sagnac effect).”
For a contentious viewpoint, here is a paper claiming interferometric measurements validate the classical approach and invalidate the relativistic approach (W. Engelhardt, Division Head, Wissenschatlicher Angestellter JET, Max-Planck-Institut für Physik)
http://www.kritik-relativitaetstheorie.de/Anhaenge/Wolfgang-Engelhardt-Sagnac.pdfQuoteIn 1925 Michelson and Gale built a huge earth-fixed Sagnac Interferometer in Illinois demonstrating that the light velocity is anisotropic on the rotating earth. For Sagnac this result did not come as a surprise having explained the underlying effect on the basis of the ether theory in 1913. The Special Relativity Theory (SRT), however, had predicted on the basis of the Lorentz Transformation (LT) that the velocity of light is isotropic in all inertial systems
.....Thanks for the great comment and explanation !
After reading these papers my conclusions are that you can dismiss the second one as looking to disprove relativity. The 1967 paper is exhaustive and it shows decisively (I could see no errors in the math) that the closed path of the Sagnac effect is an example of a "closed system" even in the case of a dispersive medium.
Edit: I suppose I should add that the EMDrive can be treated the same way(s) with the radius and area = to infinity (or the cosmological size ?) but the implications are not immediately obvious.
Edit2: Went back to check a few thoughts. Nothing was considered that could give any relevant calculation to the EMDrive, unfortunately. The only dispersion considered here would just cancel out.
Edit3: (the last ? for now)
By way of clarification, I've been following the proposition that the existance of photon dispersion in a (gravitational, for instance) accelerated frame of reference (AFR) can imply the generation of an acceleration in a stationary frame by the presence of a dispersed photon field and it's possible application to the EMDrive.
In practice, the dispersion relation is translated to an AFR in which the wavenumber dispersion disappears and the doppler shifted frequency dispersion can be used to calculate the force exerted per photon.
The required conditions for a cavity resonator would seem, so far, to be the assymetry of the cavity dispersion relation and the existance of higher order modes which exhibit "cutoff frequencies".
The 1967 paper above, and other papers I've looked at so far do not include calculations that meet those criteria.
The conservation of momentum is still to be rationalised. So far, none of the electro-gravitational papers I've seen have had the interaction arise "naturally" out of General Relativity. (that may be my own predudice, so I'm still looking)
Thanks for your patience.
Another blog post from Professor McCulloch. He links to a paper he just published describing how he believes the EM drive is a manifestation of his theory:
http://physicsfromtheedge.blogspot.com/
Awoke to memories of the '60s, ie. the Sachs-Schwebel version of GR using quaternions having an addl. coupling. Found at least one ref. this AM.
mendelsachs-fromspecialtogeneralrelativity-macrotoquantumdomains28p-120114095137-phpapp02.pdf
"This expression predicts a coupling of the ‘gravitational field’ (in terms of qk) with the matter field components Tρ to define a gravitational current contribution. The latter is not foreseen in the conventional theories that neglect the gravitational coupling to matter fields."
That expression has a form that is at least "similar" in outline to that from the cavity dispersion relation. The "gravitational current" might provide the missing momentum.
I need to find a way to get copies of the original papers which were in Il Nuovo Cimento as I recall.
Edit: Looking for,
Sachs, M. (1964).Nuovo cimento,31, 98.
Sachs, M. (1968a).International Journal of Theoretical Physics, Vol. 1, No. 4, p. 387.
Sachs, M. (1968b).Nuovo cimento,53A, 561.
Sachs, M. and Schwebel, S. L. (1961).Nuovo cimento, Supplement21, 197.
Sachs, M. and Schwebel, S. L. (1962).Journal of Mathematics and Physics,3, 843.
Sachs, M. and Schwebel, S. L. (1963).Nuclear Physics,43, 204.
it might be remarked that the quaternion form of the metrical field equations lends itself in a natural way to a unification between the inertial and gravitational manifestations of interacting matter. This is because of the basic expression of the matter fields themselves in terms of the same spinor and quaternion variables.
I have found in my research program in general relativity, that the primary contribution to the inertial mass of any local elementary matter, such as an ‘electron’, are the nearby particle-antiparticle pairs that constitute what we call the ‘physical vacuum’. [The main developments of this research are demonstrated in my two monographs: General Relativity and Matter, and Quantum Mechanics from General Relativity]. A prediction of this research program is that the main influence of these pairs on the mass of, say, an electron comes from a domain of the ‘physical vacuum’ in its vicinity, whose volume has a radius that is the order of 10^(-15) cm. Of course, the distant stars, billions of light-years away, also contribute to the electron’s mass, though negligibly, just as the Sun’s mass contribution to the weight of a person on Earth is negligible compared with the Earth’s influence on this person’s weight! Nevertheless, it was Mach’s contention that in principle all of the matter of the closed system – the nearby as well as far away constituents – determines the inertial mass of any local matter.(Bold added for emphasis) ==> this is the anti-thesis of Woodward's approach to Mach's principle!
"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.
Here is a comparison of reported measurements for EM Drives.........
reported measurement ForcePerPowerInput (milliNewtons/kW)
(* Brady c TE mode *) 21.31
(* Brady a TM mode*) 5.396
(* Brady b TM mode*) 3.000
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now?....
Yes, thanks. This is great stuff and will require a lot of reading. (not to mention the brain-busting)
But do look back at that expression in the AM reference, it looks (to me w/o justification) like it could be the "doppler frame" expression.
Edit: Found the AM paper online, (on the Beardon site, of all places! I have NO idea what this would have to do w/ free energy.)
http://www.cheniere.org/references/Symmetry_in_Electrodynamics.pdf
See p.24, the three-current density
The role of the Mach principle is revealed at this stage of the analysis. Since Fρλ depends on the spin curvature tensor Kρλ, which automatically vanishes in a vacuum (i.e. a flat spacetime), the electromagnetic field, and therefore the previously considered electric charge of any quantity of matter in a vacuum must vanish. Thus, not only the inertial mass but also the electric charge of a ‘particle’ of matter does not exist when there is no coupling to other matter. I have generalized this idea in the field theory based on General Relativity, to the case where all previously considered intrinsic properties of discrete matter, in addition to inertial mass and electric charge, vanish identically in a vacuum. This view exorcises all of the remaining features of the discrete, separable ‘elementary particle’ of matter. It is replaced with a view of matter in terms of a closed, continuous field theory, according to the theory of general relativity. I have called this view of matter, whereby all of its previously considered intrinsic properties are explained in terms of coupling within the closed system, ‘the generalized Mach principle’.
...
Sachs formally answered (in the 1960's !) the criticism that the matter in Quantum Vacuum "does not gravitate": intrinsic properties are explained in terms of coupling within the closed system, they don't really exist (thus they are "virtual") in the vacuum per se, they only become into existence when there is coupling.
...
In his website he has posted several of his articles. For example this relatively recent one on the Mach principle and origin of inertia:
http://mendelsachs.com/wp-content/uploads/articles/the-mach-principle.pdf
In that reference, Sachs convincingly argues against the approach to Mach's Principle followed by Woodward (-of course- he does not mention Woodward), he considers the particle-antiparticle pairs of the quantum vacuum having a most important effect, while the effect of distant stars is negligible:Quote from: SachsI have found in my research program in general relativity, that the primary contribution to the inertial mass of any local elementary matter, such as an ‘electron’, are the nearby particle-antiparticle pairs that constitute what we call the ‘physical vacuum’. [The main developments of this research are demonstrated in my two monographs: General Relativity and Matter, and Quantum Mechanics from General Relativity]. A prediction of this research program is that the main influence of these pairs on the mass of, say, an electron comes from a domain of the ‘physical vacuum’ in its vicinity, whose volume has a radius that is the order of 10^(-15) cm. Of course, the distant stars, billions of light-years away, also contribute to the electron’s mass, though negligibly, just as the Sun’s mass contribution to the weight of a person on Earth is negligible compared with the Earth’s influence on this person’s weight! Nevertheless, it was Mach’s contention that in principle all of the matter of the closed system – the nearby as well as far away constituents – determines the inertial mass of any local matter.
(Bold added for emphasis) ==> this is the anti-thesis of Woodward's approach to Mach's principle!
...
The "delayed action at a distance"of Feynman and Wheeler is restored to currency. The "advanced" solutions take their place beside the "retarded" solutions in a single, complete space-time.
...
...
Sachs formally answered (in the 1960's !) the criticism that the matter in Quantum Vacuum "does not gravitate": intrinsic properties are explained in terms of coupling within the closed system, they don't really exist (thus they are "virtual") in the vacuum per se, they only become into existence when there is coupling.
...
Sachs formally answered (in the 1960's !) the criticism that the matter in Quantum Vacuum "does not gravitate": intrinsic properties are explained in terms of coupling within the closed system, they don't really exist (thus they are "virtual") in the vacuum per se, they only become into existence when there is coupling.
so how does one create this coupling?
...
Sachs formally answered (in the 1960's !) the criticism that the matter in Quantum Vacuum "does not gravitate": intrinsic properties are explained in terms of coupling within the closed system, they don't really exist (thus they are "virtual") in the vacuum per se, they only become into existence when there is coupling.
so how does one create this coupling?
See: http://link.springer.com/static-content/lookinside/986/art%253A10.1007%252FBF02755823/000.png
...
Sachs formally answered (in the 1960's !) the criticism that the matter in Quantum Vacuum "does not gravitate": intrinsic properties are explained in terms of coupling within the closed system, they don't really exist (thus they are "virtual") in the vacuum per se, they only become into existence when there is coupling.
so how does one create this coupling?
See: http://link.springer.com/static-content/lookinside/986/art%253A10.1007%252FBF02755823/000.png
Since I am not a physicist, and I didnt sleep at a holiday in express last night. I will not even begin to pretend I understood most of what that reply was attempting to show. All I could get out of it was Sachs provided a point of clarification on why the complaint of his theory lacking internal consistency was not correct. other than that didnt see an argument for how one could physically force the virtual particles to experience coupling and gain their intrinsic properties. Though I suspect this experiment may light the path towards doing something of the sort
http://www.bibliotecapleyades.net/ciencia/secret_projects/project077.htm (http://www.bibliotecapleyades.net/ciencia/secret_projects/project077.htm)
Curious that there has been no coverage of this in the mainstream science press for the end of year, not a mention in anyone that I've seen roundups of 2014.
For comparison the detection of primordial gravity waves has been well covered even though this discovery has been heavily disputed since.
OT: I found a thing and put it over in the "New Hope For Warp Drive" thread. it does have some interesting details that can be examined in a very loose sort of way. not a technical paper by any means but it does describe the set up and effects. i found it interesting the weight of his test object and magnitude of effect on it.
When you say that it means it really was topical for this thread after all.
Not much to go by, it seems to be a 2 meter (146 MHz) asymmetric resonant antenna, so it could meet the requirement for a "Sachs-Schwebel" gravitational current generator instead of a warp drive. It could also be seeing electromagnetic forces between the antenna and the faraday cage walls which are in the near field. The interferometer tests are interesting, but again, not much data.
There is a paper of sorts: http://swdllc.paresspacewarpresearch.org/PressRelease/Press.htm
On another forum they were discussing how such drives could accelerate the end of the universe, I looked at some of the explanations on there as too what was meant but they completely lost me I'm afraid to admit?
On another forum they were discussing how such drives could accelerate the end of the universe, I looked at some of the explanations on there as too what was meant but they completely lost me I'm afraid to admit?
well...that's a step ahead of what is already a shaky concept or two. but I think anything that is a linear drive like the thing i was just talking about would be an infinitesimal perturbation in the scheme of the whole cosmos. but i have heard arguments about collapsing the vacuum state of the universe. but i think that that was in reference to collider experiments and not warp drives or em drives.
oh they already did. it's just that after the LHC black hole media hype no one paid attention to the "collapse of the vacuum state" scare. i remember seeing articles about it in new scientist if i recall right.On another forum they were discussing how such drives could accelerate the end of the universe, I looked at some of the explanations on there as too what was meant but they completely lost me I'm afraid to admit?
well...that's a step ahead of what is already a shaky concept or two. but I think anything that is a linear drive like the thing i was just talking about would be an infinitesimal perturbation in the scheme of the whole cosmos. but i have heard arguments about collapsing the vacuum state of the universe. but i think that that was in reference to collider experiments and not warp drives or em drives.
God help us if the media ever get hold of this, you can imagine the headlines now!
ok. this is interesting... neutrinos that collide with nuclei at an oblique angle create particles out of the vacuum. evidently said new particles don't annihilate with a virtual twin? is that right?
http://phys.org/news/2014-12-neutrinos-full-on-glancing.html
so here is a real interaction with the vacuum. that was being argued a few pages back WRT Dr White's Theory of how QVPTs work i think.
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully.
Has there been the least indication yet when we are too get some more results in relation to those who are experimenting in this area?
Curious that there has been no coverage of this in the mainstream science press for the end of year, not a mention in anyone that I've seen roundups of 2014.
For comparison the detection of primordial gravity waves has been well covered even though this discovery has been heavily disputed since.
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully.
Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.
But neutrinos are "free" so there is no real cost or at least not a commensurate cost similar to banging high energy gamma photons together. Further I know no way of increasing the amount ambient neutrinos. Since only an occasional neutrino collides with anything and of those only a few do the glancing blow trick I was not shooting for using them for a drive of any sort. What i was pointing at was the vacuum interaction itself; which you covered nicely in the first line of your reply. :)ok. this is interesting... neutrinos that collide with nuclei at an oblique angle create particles out of the vacuum. evidently said new particles don't annihilate with a virtual twin? is that right?
http://phys.org/news/2014-12-neutrinos-full-on-glancing.html
so here is a real interaction with the vacuum. that was being argued a few pages back WRT Dr White's Theory of how QVPTs work i think.
Ok, let's try this : there is no question that there can be real interaction with the vacuum (vacuum polarization, pair production from strong electric field or gamma photon bouncing on nucleus or photon/photon...) the question is at what energetic cost ? If there is conservation of momentum_energy in those interactions then you are no better of than with the photon rocket (again) or shooting the supposedly available neutrinos backward (almost the same).
None of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive.Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.
I suspect there are people who may disagree with you with that statement, but that's not my debate to have.:)Curious that there has been no coverage of this in the mainstream science press for the end of year, not a mention in anyone that I've seen roundups of 2014.
For comparison the detection of primordial gravity waves has been well covered even though this discovery has been heavily disputed since.
The primordial gravity wave research was peer reviewed and done by scientists who are respected by the rest of the scientific community. The debate over it was from within the scientific community. That's why the mainstream media covered it.
The reactionless drive work is entirely outside the scientific mainstream, and every mainstream scientist who has examined it has found it to be without sufficient evidence to claim a discovery. That's why the mainstream media has not covered it much.
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully.
Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.
No, it's TRL-1. Basic research has not even established sufficient evidence of anything anomalous to convince even a small part of the mainstream physics community.
In his website he has posted several of his articles. For example this
relatively recent one on the Mach principle and origin of inertia:
http://mendelsachs.com/wp-content/uploads/articles/the-mach-principle.pdf
In that reference, Sachs convincingly argues against the approach to Mach's
Principle followed by Woodward (-of course- he does not mention Woodward),
he considers the particle-antiparticle pairs of the quantum vacuum having
a most important effect, while the effect of distant stars is
negligible:Quote from: SachsI have found in my research program in general relativity, that the primary(Bold added for emphasis) ==> this is the anti-thesis of Woodward's
contribution to the inertial mass of any local elementary matter, such as an
'electron', are the nearby particle-antiparticle pairs that constitute what
we call the 'physical vacuum'. [The main developments of this research are
demonstrated in my two monographs: General Relativity and Matter, and
Quantum Mechanics from General Relativity]. A prediction of this research
program is that the main influence of these pairs on the mass of, say, an
electron comes from a domain of the 'physical vacuum' in its vicinity, whose
volume has a radius that is the order of 10^(-15) cm. Of course, the distant
stars, billions of light-years away, also contribute to the electron's mass,
though negligibly, just as the Sun's mass contribution to the weight of a
person on Earth is negligible compared with the Earth's influence on this
person's weight! Nevertheless, it was Mach's contention that in principle
all of the matter of the closed system - the nearby as well as far away
constituents - determines the inertial mass of any local matter.
approach to Mach's principle!
...
52.Terletskiy, Y. P. Paradoxes of the Theory of Relativity. Moscow: Nauka, 1966. 120 pp.
58.Terletskiy, Ya. P., and Yu. P. Rybakov. Electrodynamics. Moscow: Vyssh. shk., 1990. 352 pp.
Which "sounds like" a Russian invention of the Sachs-Schwebel ( quadrigues vs quarternions )
...
In accepting negative mass, one must therefore accept the quadrigue (group of four) of particles
of Terletskiy (88), which is neatly buttressed by Dirac’s quadrupling of states in his quantum theory. It
is also a remarkable turn of events in the modeling of the physical vacuum as a polarizing medium.
Terletskiy’s quadrigue is actually four particles (or, actually, four electrical charges, masses, magnetic
moments and spin moments), the sum of which equal zero – from which, interestingly enough, one can
derive any two pairs of particles in which their electrical charges, masses, magnetic and spin moments
equal zero! This allows theorists to build a basic model of cella (or distinguishable compartments) of
the physical vacuum as a whole-cloth neutral polarizing medium, from which then three kinds of
physical vacuums can manifest: (a) an absolute physical vacuum, represented by the quadrigues; (b) a
physical vacuum of matter, which is made up of particles, one of which is an ordinary one; and (c) a
physical vacuum of antimatter, which is made up of particle pairs, one of which is an antiparticle.
What is most remarkable is that the absolute physical vacuum is described quite well by Maxwell and
Heaviside equations, and thus in the absolute physical vacuum, the polarization model breaks down
into two independent models: the Maxwell theory of electromagnetism, and the Heaviside theory of
gravitational spin. But in physical reality, the relationships of electrical and gravitational polarizations
and of magnetic and spin polarization in the absolute- as well as in the physical matter vacuums come
out as quite a unified system of equations that become the basis of a combined electrogravitodynamic
model of matter electrogravitogeneration (via electrical charges and magnetic polarizations) and
continuum dynamics (via masses and moments of the quantity of movement set by way of the
Heaviside equations).
We have investigated in this work the quaternionic momentum eigen value problem in quantum mechanics. We have written the wave function, energy and momentum of the particle as quaternionic quantities. The momentum eigen value equation reveals that the scalar and vector parts of the wavefunction are governed by a new wave equation. This is a new equation that we wish it will describe bosons and fermions. When the interaction of the particle with an electromagnetic field is introduced a spin term appeared in the equation of motion. The scalar equation doesn't change due to the interaction of the electromagnetic field with the particle. However, the vector equations are altered. We generalized the ordinary uncertainty relation to quaternionic one. This generalization provides us with the energy momentum relation of Einstein and the remaining uncertainty relations. Hence, by adopting the quaternionic quantum mechanics, namely, Dirac equation, we arrived at a dissipative or generalized
Klein-Gordon equation with a particle spin. This formalism gives rise to the generation of spin angular momentum of the particle when a photon field is introduced in the equation of motion. Further investigation is going on to explore the physics of these two waves
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully.
Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.
No, it's TRL-1. Basic research has not even established sufficient evidence of anything anomalous to convince even a small part of the mainstream physics community.
http://www.researchgate.net/profile/Arbab_Arbab/publication/51916988
_The_unified_quantum_wave_equation/links/0912f50de92ef30406000000.pdfQuoteWe have investigated in this work the quaternionic momentum eigen value problem in quantum mechanics. We have written the wave function, energy and momentum of the particle as quaternionic quantities. The momentum eigen value equation reveals that the scalar and vector parts of the wavefunction are governed by a new wave equation. This is a new equation that we wish it will describe bosons and fermions. When the interaction of the particle with an electromagnetic field is introduced a spin term appeared in the equation of motion. The scalar equation doesn't change due to the interaction of the electromagnetic field with the particle. However, the vector equations are altered. We generalized the ordinary uncertainty relation to quaternionic one. This generalization provides us with the energy momentum relation of Einstein and the remaining uncertainty relations. Hence, by adopting the quaternionic quantum mechanics, namely, Dirac equation, we arrived at a dissipative or generalized
Klein-Gordon equation with a particle spin. This formalism gives rise to the generation of spin angular momentum of the particle when a photon field is introduced in the equation of motion. Further investigation is going on to explore the physics of these two waves
So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully.
Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.
No, it's TRL-1. Basic research has not even established sufficient evidence of anything anomalous to convince even a small part of the mainstream physics community.
Being believed by the mainstream community has nothing to do with TRL. If it works, it works. And if the Chinese fly their Emdrive (possibly this year?) and get acceleration, I doubt they'll care what anyone else thinks however loudly they say it can't be true.
I suspect these things really will be operational before a lot of the mainstream starts accepting them, the will to disbelieve is that strong.
Source
Article: Physics of Extreme Gravitomagnetic and Gravity-Like Fields for Novel Space Propulsion and Energy Generation
Jochem Hauser, Walter Dröscher
[Hide abstract]
ABSTRACT: In 2006 Tajmar et al. reported on the measurements of extreme gravitomagnetic fields from small Nb rings at cryogenic temperatures that are about 18 orders of magnitude larger than gravitomagnetic fields obtained from GR (general relativity). Cifuolini in 2004 and the NASA-Stanford Gravity Probe-B experiment in 2007 confirmed the Lense-Thirring effect as predicted by GR (gravitomagnetic fields generated by a rotating massive body, i.e. Earth) within some 10%. In 2007 gravitomagnetic fields generated by a rotating cryogenic lead disk were measured by Graham et al. Though these measurements were not conclusive (the accuracy of the laser gyrometer was not sufficient to produce a standard deviation small enough) their experiment seems to have seen the same phenomenon reported earlier by Tajmar et al., termed parity violation. This means that gravitomagnetic fields produced by the cryogenic rotating ring or disk vary substantially and change sign for clockwise and counter-clockwise directions of rotation. The experimental situation therefore occurs to be contradictory. On the one hand GR has been confirmed while at the same time, there seems to be experimental evidence for the existence of extreme gravitomagnetic fields that cannot be generated by the movement of large masses. If these experiments can be confirmed, they give a clear indication for the existence of additional gravitational fields of non-Newtonian nature. As was shown by the GP-B experiment, measuring gravitomagnetic fields from GR poses extreme difficulties. Therefore a novel physical mechanism should exist for the generation of gravity-like fields, which might also provide the key to gravitational engineering similar to electromagnetic technology
: Emerging Physics for Novel Field Propulsion Science
Jochem Hauser, Walter Dröscher
[Hide abstract]
ABSTRACT: All space vehicles in use today need some kind of fuel for operation. The basic physics underlying this propulsion principle severely limits the specific impulse and/or available thrust. Launch capabilities from the surface of the Earth require huge amounts of fuel. Hence, space flight, as envisaged by von Braun in the early 50s of the last century, will not be possible using this concept. Only if novel physical principles are found can these limits be overcome. Gravitational field propulsion is based on the generation of gravitational (gravity-like) fields by manmade devices. In other words, gravity-like fields should be experimentally controllable. Present physics believes that there are four fundamental interactions: strong (nuclei), weak (radioactive decay), electromagnetism and Newtonian gravitation. As experience has shown for the last six decades, none of these physical interactions is suitable as a basis for novel space propulsion. None of the advanced physical theories like string theory or quantum gravity, go beyond these four known interactions. On the contrary, recent results from causal dynamical triangulation simulations indicate that wormholes in spacetime do not seem to exist, and thus even this type of exotic space travel may well be impossible. Recently, novel physical concepts were published that might lead to advanced space propulsion technology, represented by two additional long range gravitational-like force fields that would be both attractive and repulsive, resulting from interaction of gravity with electromagnetism. A propulsion technology, based on these novel long range fields, would be working without propellant
Ok, paging Doctor Rodal for a translation here (from Not so sure of its' link);
Very nice, if I'm reading it right, there may be the implication that the spins of the counter-propagating cavity photons could add to 2 in an interaction. But, at the moment, I don't see that generating enough force. (who knows at this point, .... it would need a very high vacuum energy density ?)
Along the way, Zvi, John Joseph and Henrik, thanks to the time-honored method of “just staring at” the loop integrand provided by unitarity, also stumbled on a new property of gauge theory amplitudes, which tightly couples them to gravity. They found that gauge theory amplitudes can be written in such a way that their kinematic part obeys relations that are structurally identical to the Jacobi identities known to fans of Lie algebras. This so-called color-kinematics duality, when achieved, leads to a simple “double copy” prescription for computing amplitudes in suitable theories of gravity: Take the gauge theory amplitude, remove the color factors and square the kinematic numerator factors. Crudely, a graviton looks very much like two gluons laid on top of each other. If you’ve ever looked at the Feynman rules for gravity, you’d be shocked that such a simple prescription could ever work, but it does. Although these relations could in principle have been discovered without unitarity-based methods, the power of the methods to provide very simple expressions, led people to find initial patterns, and then easily test the patterns in many other examples to gain confidence.
http://www.emdrive.com/EmDriveForceMeasurement.pdf
New info:
Some clarification from Shawyer. Helps to clear up some of the arguments we had about how Shawyer uses thrust and reaction, and which way it moves.
http://www.emdrive.com/EmDriveForceMeasurement.pdf
New info:
Some clarification from Shawyer. Helps to clear up some of the arguments we had about how Shawyer uses thrust and reaction, and which way it moves.
Hold the phone... am I reading this right. You can only ever measure thrust if the cavity is accelerating? So just sitting on a flat floating stationary table top should yield no force, the same with when the cavity is moving at constant velocity. Did I mis interpret that pdf?
if so that pushes it into Dr Woodward and vis inert or "fictitious" fields such as inertia, and gravity. (I'm currently reading Woodward's book )
Clearly, in a static situation, where T and R both exist as forces, they will cancel out. Thus any attempt to measure them by simply placing the thruster vertically on a set of scales will fail. If however the thrust is sufficient such that a=-g,then the thruster could be made to hover above the scales.
It therefore appears that a force measurement can only be made in a dynamic environment, ideally by allowing the thruster to accelerate, ...
Considering that NASA will fly just about anything of scientific note into space for the cost of the paperwork (and the Ukrainians will fly anything for you for less than $100k) most of these gadgets could be demonstrated in LEO.. if they worked.
So, before I trundle off to bed...(be'in old an' all)It would a big surprise if this would be possible within General Relativity: it would certainly go against what Sean M. Carroll and John Baez have stated (particularly concerning frames of reference). The implication is that extra coupling terms and/or nonlinearities would be needed, such as Sachs-Schwebel.
When we are in the AFR that removes the cavity dispersion at the expense of splitting the frequency into doppler components, and giving us a flat metric tensor, what tensor quantities can we generate which will give zero force in this frame (despite the difference in frequency) and allow us to find the force in the rest frame of the cavity. Then the question is: can this be done in GR or does it need extensions (such as Sachs-Schwebel, etc)
By the way, John Baez (in his blog https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4 , answering correspondence) had some non-flattering things to say about Woodward's approach as well.
As Chris Bergin made clear, the purpose of this forum is to deal with SPACEFLIGHT APPLICATIONS (of EM Drives: those propellantless drives comprised of a microwave cavity as the devices tested by Shawyer in the UK, Prof. Juan Yang in China and Brady, March, White, et.al. at NASA):
Why is this prescription by Chris Bergin being ignored?
Although the latest Woodward experiments (Fearn, Zachar, Woodward & Wanser) show that it takes 20,000 times more power to produce a given level of thrust than the power required to produce the same thrust for the EM Drive (Shawyer demo), and therefore these experiments do not constitute "EM Drive Spaceflight Applications" (as instructed by Chris Bergin) Woodward fans persist on carrying a debate on this thread rather than their own Woodward thread.
Frankly, I don't understand what is the goal being pursued here by Woodward-effect fans to insist to carry arguments concerning Woodward's theory and experiments in this thread.
The curtailment of the previous EM Drive thread by this forum's moderator was due to disruptive discussions regarding the validity of the Woodward effect, including a negative review of Woodward's book by a physicist.
Good that Shawyer has clarified the force measurement. Referring to his Fig. 1 from the paper
http://www.emdrive.com/EmDriveForceMeasurement.pdf
and reproduced below, I conclude he is saying the force that is acting on the EM-drive is in the same direction as the vector labeled T. The only difficulty I have with this is from looking at the videos of the EM=drive. When it is operating it moves with the small end forward.
https://www.youtube.com/watch?v=57q3_aRiUXs
In the earlier thread I stated that maybe the thrust was due to heat convection from the sloped sides. This was dismissed because the EM-drive moves in the opposite direction as seen in the video.
It therefore appears that a force measurement can only be made in a dynamic environment, ideally by allowing the thruster to accelerate, measuring that acceleration, and then calculating the thrust from T = - Ma. This is not a very easy method, although the SPR Demonstrator Thruster was successfully tested in this way on a rotary air bearing
...and your point is?who me? You trying to get me in trouble? ;)
Looking over the last several posts, I see absolutely nothing related to space flight applications. All I see is more of exactly what got the previous version of this thread to disappear for a while.
None of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive.Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.
....
Beyond unorthodox pseudo-forces orientation conventions, this "dynamic environment" condition seems quite problematic and ill defined. Ignoring theoretical musings, Shawyer makes 3 phenomenological predictions :
....
- That a horizontal EM thruster restrained from accelerating horizontally (through an opposing spring) will record no thrust, page 3 figure 3 "Because the thruster is at rest, no force will be measured on the load cell"
....
None of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive.Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.
Anyone ? Anyone ?
I mean, actual spaceflight application. Desaturation spends fuel. Can we get a propellantless desaturation device, with main attitude control provided by reaction wheels ?
...
I thought I would make up a summary of the dispersion relation approach, as I keep doing this in bits and pieces.
....
The difference from other calculations is that there is a term dependent on the particular mode of the cavity, (X[subm,n])^2, not just the area of the end plates.
I got some help making those equations look pretty with LaTeX, but I'm not sure it's rendered correctly. Are these accurate?
Thrust per photon:
(http://i.imgur.com/V24BnsY.png)
\mathrm T = \left( \mathrm X _{m,n} \right) ^2 \left( \frac{\hslash}{4} \pi ^2 \right) \lambda \left( \frac{1}{a^2} - \frac{1}{b^2} \right)
Force on the photons:
(http://i.imgur.com/YvP9Zj9.png)
\mathrm{T = P} \mathbb Q \left( \mathrm X_{m,n} \right) ^2 \left( \frac{1}{\mathrm{c}} 4 \pi ^2 \right) \lambda^2 \left( \frac{1}{a^2} - \frac{1}{b^2} \right)
Thrust per photon, with Planck's constant instead of the reduced constant:
(http://i.imgur.com/Lm9OVYD.png)
I think that the factors of (Pi^2) in the first Latex equation and 4 Pi^2 in the 2nd Latex equation are in an incorrect position (they should be in the denominator instead of the numerator): the factors should be (h/(4 Pi^2)) in the first equation and (1/(c 4 Pi^2)) in the second equation.
I think that the factors of (Pi^2) in the first Latex equation and 4 Pi^2 in the 2nd Latex equation are in an incorrect position (they should be in the denominator instead of the numerator): the factors should be (h/(4 Pi^2)) in the first equation and (1/(c 4 Pi^2)) in the second equation.
Hmm. Are you sure? Oh well, here they are just the same:
(http://i.imgur.com/0AT8Jep.png)
(http://i.imgur.com/NjgzBtl.png)
PS: I agree with Notsosureofit, the second equation would better read NT, where "N" stands for the thrust of all the photons, instead of the thrust of a single photon "T".
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.
Time to "let it go"........prove it one way or another. The energy spent back and forth could have been put into a cad file, exported into STEP or IGES format by now....(someone please do it)
Then maybe if time permits i'll print out a test model.
Someone then talk maybe to Nanoracks, and lets get it tested. :)
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.
Time to "let it go"........prove it one way or another. The energy spent back and forth could have been put into a cad file, exported into STEP or IGES format by now....(someone please do it)
Then maybe if time permits i'll print out a test model.
Someone then talk maybe to Nanoracks, and lets get it tested. :)
What are STEP and IGES ?
what is the correct force expression for the force on the solenoid and
second, the assumption that Newton’s third law holds in the sense that the
change of the solenoid’s momentum is compensated by the change of the
electron’s momentum. The discussion of “Feynman’s paradox” shows that
the latter is not always the case. It is possible that a change in field momentum
is an essential part of the Aharonov-Bohm discussion, which is exactly
what Aharonov and Casher claim in 1984 [45]. Many theoretical papers have
discussed this issue [16, 17, 36, 37]. These discussions involve imbalanced
forces, field momentum and relativistic terms, all of which are present in our
above discussion. However, none of the discussions gives an explicit and exact
derivation of the delicate balance of all the momentum terms, but often
resort to a treatment of simplified systems. For example, Aharonov and D.
Rohrlich [16] discuss a flux tube with a radially moving charge, instead of a
charge passing by the flux tube. While the issue of whether the charge distribution
of the solenoid is perturbed has been addressed [17, 36, 46], none of
the discussions mention the relativistic electric field imbalance.
As it is possible to describe a solenoid as a collection of moving charged
particles, the above treatment of the Feynman paradox provides hope to settle
the theoretical discussion on forces. Integration over a solenoidal current
distribution would provide an exact derivation of momentum conservation
for the Aharonov-Bohm case.
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.
Again, NASA tested what, a 20 watt setup ? That is within power budget of a 3U cubesat. Flight model ? Demonstrate torque, if not directional thrust ?
"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.
Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.
Notice that the force per power input reported by Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives". Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:
reported measurement ForcePerPowerInput (milliNewtons/kW)
(* Cannae Superconducting *) 761.9 to 952.4
(* Shawyer Demo *) 80 to 243
(* Shawyer Experimental *) 18.82
(* Brady c TE mode *) 21.31
(* Brady a TM mode*) 5.396
(* Brady b TM mode*) 3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176
lengths in meter
rfFrequency in 1/second (microwave frequency during test)
power in watts
force in milliNewtons
force per PowerInput in milliNewtons/kW
c= 299705000 m/s (speed of light in air)
c= 299792458 m/s (speed of light in vacuum) (for Cannae Superconducting)
(the difference between c in air compared to c in vacuum is negligible)
Note: SmallDiameter for Shawyer's EM Drives obtained from his reported ShawyerDesignFactor .
Force/PowerInput of a Photon Rocket = 1 / c
(* Cannae Superconducting *)
rfFrequency = 1.047*10^9;
cavityLength = 0.01+0.004+0.006+0.01 = 0.03;
bigDiameter =(22.86-2*(0.00430)) = 0.220;
smallDiameter = bigDiameter-2*0.01=0.200;
power = 10.5
Q = 1.1*(10^7)
measured force = 8 to 10
measured ForcePerPowerInput = 761.9 to 952.4
Force/PowerInput of a Photon Rocket =0.003336
measured ForcePerPowerInput to the one of a photon rocket = 228,400 to 285,500
(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;
bigDiameter=0.16;
smallDiameter=0.127546;
power = 850
Q = 5900
measured force = 16
measured ForcePerPowerInput = 18.82
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =5,640
(* Shawyer Demo *)
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
All Brady cases have the following dimensions:
cavityLength=0.332;
bigDiameter=0.397;
smallDiameter=0.244;
(* Brady a TM mode*)
rfFrequency=1.9326*10^9;
power = 16.9
Q = 7320
measured force = 0.0912
measured ForcePerPowerInput = 5.396
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =1,617.2
(* Brady b TM mode*)
rfFrequency=1.9367*10^9;
power = 16.7
Q = 18100
measured force = 0.0501
measured ForcePerPowerInput = 3.000
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =899.12
(* Brady c TE mode *)
rfFrequency = 1.8804*10^9;
power = 2.6
Q = 22000
measured force = 0.05541
measured ForcePerPowerInput = 21.31
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =6,386.7
(* Fearn, Zachar, Woodward & Wanser*)
rfFrequency = 39,300;
power = 170
measured force = 0.002
measured ForcePerPowerInput = 0.01176
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 3.526
None of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive.Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.
Anyone ? Anyone ?
I mean, actual spaceflight application. Desaturation spends fuel. Can we get a propellantless desaturation device, with main attitude control provided by reaction wheels ?
Again, from the claimed experimental setups, are the reported angular momentums even on a scale where they could turn a cubesat - even if it takes a long time to do so ? Its not like torquer rods are fast or anything, but they only work within earths magnetic field.
And if it cannot turn a cubesat, the entire thing is no better than Steorn Orbo, is it ?
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.
Again, NASA tested what, a 20 watt setup ? That is within power budget of a 3U cubesat. Flight model ? Demonstrate torque, if not directional thrust ?
....
Ok, let's break it down a bit simpler.
How many units of energy are being used to produce how many units of thrust? Newtons as the unit of measure could work.
Throwing around ideas/stuff to think about here:
Since the thrust/power ratio of these devices is pretty bad, they are severely limited by the amount of electrical power you can put on orbit.
(http://4.bp.blogspot.com/-IOhb45CEI9I/URSurOhJNPI/AAAAAAAAh5M/c5oSLgis9qE/s640/emdrivespaceplane3.png)Throwing around ideas/stuff to think about here:
Since the thrust/power ratio of these devices is pretty bad, they are severely limited by the amount of electrical power you can put on orbit.
If it works as Shawyer claims, the superconducting version will be producing far more thrust:
http://emdrive.com/faq.html
"The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities."
You meant to write "assuming a superconducting EmDrive with a Q of 5 * 10^9" = 5,000,000,000 (five billion) (rather than Q = 5 x 109 =545).
In his IAC 2014 October 2014 presentation Shawyer (in his slide #3 in http://www.emdrive.com/iac2014presentation.pdf ) instead uses a projected Q = 5*(10^7), which is 100 times less than the value assumed by Shawyer for the above 30kN/kW projection.
Reviewing actual published data, the maximum Q actually measured for a superconducting EM Drive I have seen reported is for the Canae superconducting drive experiment which gave a Q = 1.1*(10^7), this is 500 times less than the value assumed by Shawyer for the above 30kN/kW projection.
Also comparing with actual experimental data, Canae's measured ForcePerPowerInput for the superconducting Canae experiment was only 0.7619 to 0.9524 N/kW, which is 31500 times less than the 30kN/kW projection, therefore besides the decrease in thrust by a factor of 500 due to the lower actual Q, there was another factor of decrease in thrust (by a factor of 63 times) in the actual performance of the experiment (500*63=31500).
You meant to write "assuming a superconducting EmDrive with a Q of 5 * 10^9" = 5,000,000,000 (five billion) (rather than Q = 5 x 109 =545).
In his IAC 2014 October 2014 presentation Shawyer (in his slide #3 in http://www.emdrive.com/iac2014presentation.pdf ) instead uses a projected Q = 5*(10^7), which is 100 times less than the value assumed by Shawyer for the above 30kN/kW projection.
Reviewing actual published data, the maximum Q actually measured for a superconducting EM Drive I have seen reported is for the Canae superconducting drive experiment which gave a Q = 1.1*(10^7), this is 500 times less than the value assumed by Shawyer for the above 30kN/kW projection.
Also comparing with actual experimental data, Canae's measured ForcePerPowerInput for the superconducting Canae experiment was only 0.7619 to 0.9524 N/kW, which is 31500 times less than the 30kN/kW projection, therefore besides the decrease in thrust by a factor of 500 due to the lower actual Q, there was another factor of decrease in thrust (by a factor of 63 times) in the actual performance of the experiment (500*63=31500).
On the plus side, with the right power source, 0.7619 Newtons from a kilowatt of electricity is still, probably, enough thrust to displace rockets for orbital insertion. It's not competing with airplanes, but it is an exciting number. :)
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.
Again, NASA tested what, a 20 watt setup ? That is within power budget of a 3U cubesat. Flight model ? Demonstrate torque, if not directional thrust ?
I suggest those of you concerned that NASA is not testing this yet in space make your representations to them.:)
The future? More power.
Two interesting things I found about high power space flight projects at none other than JSC. What is also interesting is that both of these mention Q-thrusters.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140004802.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140004416.pdf
it may be that i have an outdated reader but those pdfs fail to load for me. the first gets 2/3s of the way loaded according to the progress bar and then hangs. the second gets 1/4 of the way loaded and then hangs.NTRS does that a lot with firefox, try chrome or curl/wget
:(
Thanks. :)it may be that i have an outdated reader but those pdfs fail to load for me. the first gets 2/3s of the way loaded according to the progress bar and then hangs. the second gets 1/4 of the way loaded and then hangs.NTRS does that a lot with firefox, try chrome or curl/wget
:(
The near term focus of the laboratory work is focused on gathering performance data to support development of a Q-thruster engineering prototype targeting Reaction Control System (RCS) applications with force range of 0.1-1 N with corresponding input power range of 0.3-3 kW. Up first will be testing of a refurbished test article to duplicate historical performance on the high fidelity torsion pendulum (1-4 mN at 10-40 W). The team is maintaining a dialogue with the ISS national labs office for an on orbit DTO.
How would Q-thrusters revolutionize human exploration of the outer planets? Making minimal extrapolation of performance, assessments show that delivery of a 50 mT payload to Jovian orbit can be accomplished in 35 days with a 2 MW power source [specific force of thruster (N/kW) is based on potential measured thrust performance in lab, propulsion mass (Q-thrusters) would be additional 20 mT (10 kg/kW), and associate power system would be 20 mT (10 kg/kW)]. Q-thruster performance allows the use of nuclear reactor technology that would not require MHD conversion or other more complicated schemes to accomplish single digit specific mass performance usually required for standard electric propulsion systems to the outer solar system. In 70 days, the same system could reach the orbit of Saturn.
In this report http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf NASA's Dr. White wrote of his continuing "dialogue with the (International Space Station) ISS national labs office for an on orbit DTO (On Orbit Detailed Test Objectives)" of the EM Drive (which he calls "Q-Thruster"):
The "Q-Thruster" in this case appears to be a Woodward/ME device.
In this report http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf NASA's Dr. White wrote of his continuing "dialogue with the (International Space Station) ISS national labs office for an on orbit DTO (On Orbit Detailed Test Objectives)" of the EM Drive (which he calls "Q-Thruster"):The "Q-Thruster" in this case appears to be a Woodward/ME device.
QuoteThe "Q-Thruster" in this case appears to be a Woodward/ME device.
Yes. No. Sort of.
Despite claimed differing operating principles, the 'Q-Thruster' and Woodward/ME device appear to differ in minor detail, in terms of construction and results. At least that is my (possibly badly flawed) understanding.
Heated debates about this in the old thread contributed to its demise. We attempt to keep Woodward/Mach out of this thread, but the equations and thoughts keep heading that way.
In this report http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf NASA's Dr. White wrote of his continuing "dialogue with the (International Space Station) ISS national labs office for an on orbit DTO (On Orbit Detailed Test Objectives)" of the EM Drive (which he calls "Q-Thruster"):
The "Q-Thruster" in this case appears to be a Woodward/ME device.
QuoteThe "Q-Thruster" in this case appears to be a Woodward/ME device.
Yes. No. Sort of.
....
Great posts by Rodal and Mulletron.
And I concur: the next step is to firmly cement the scientific nature of the mentioned thrusters (them being falsifiable), by providing additional replications and tests. Theories can come later, if empiric evidence is there.
It doesn't matter if H. White's theory is right or wrong, the same as Woodward's (or Shawyer's, which is most likely wrong). What matters is that the phenomena related to those theories would have evidence of being real.
Humanity has used real phenomena nobody can explain for millenia, and this way before even having complete formal descriptions/theories for them. We still do, as we don't know the provenance and nature of inertia and gravity, and they are part of our everyday lives and expected to work for a lot of technology to function as well.
All well & good unless it proves through theory they are doing some fundamental damage. Something raised in fiction by a Star Trek: The Next Generation & the use of warp drive damaging the universe.
Big difference between figure 5 here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf (same old Q-thruster paper we've been reading)
and figures 2/3 here: http://www.jhuapl.edu/techdigest/TD/td2804/McNutt.pdf (MPD thrusters/Nuclear power)
The difference between Jupiter transit times is astonishing. Not to mention you don't have to carry aloft ~75 percent of your mass as propellant. Disclaimer though, the empty mass of Jupiter mission spacecraft (fig. 2 McNutt) is ~4081 metric tons (why so massive? anybody know? This is about half as much as of one of these metal monstrosities http://en.wikipedia.org/wiki/Ticonderoga-class_cruiser), compared to the 90 metric tons (fig. 5 White) (50mT payload, propulsion mass 20 mT, 2MW power system 20 mT. I'm not sure what the author intended here. I'm assuming a spacecraft with a mass of at least 90 metric tons total though.)
Anybody have any idea how massive this is? http://en.wikipedia.org/wiki/High_beta_fusion_reactor
It would be interesting to put together an imaginary ship using say....a cluster of the Brady c TE mode articles @21.31 milliNewtons/kW + a Lockheed Martin 100MW miracle reactor -reasonable electrical power and RF efficiency losses, to see if anything interesting can be done. Is there even enough information for this to be do-able yet?
Big difference between figure 5 here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf (same old Q-thruster paper we've been reading)
and figures 2/3 here: http://www.jhuapl.edu/techdigest/TD/td2804/McNutt.pdf (MPD thrusters/Nuclear power)
The difference between Jupiter transit times is astonishing. Not to mention you don't have to carry aloft ~75 percent of your mass as propellant. Disclaimer though, the empty mass of Jupiter mission spacecraft (fig. 2 McNutt) is ~4081 metric tons (why so massive? anybody know? This is about half as much as of one of these metal monstrosities http://en.wikipedia.org/wiki/Ticonderoga-class_cruiser), compared to the 90 metric tons (fig. 5 White) (50mT payload, propulsion mass 20 mT, 2MW power system 20 mT. I'm not sure what the author intended here. I'm assuming a spacecraft with a mass of at least 90 metric tons total though.)
Anybody have any idea how massive this is? http://en.wikipedia.org/wiki/High_beta_fusion_reactor
It would be interesting to put together an imaginary ship using say....a cluster of the Brady c TE mode articles @21.31 milliNewtons/kW + a Lockheed Martin 100MW miracle reactor -reasonable electrical power and RF efficiency losses, to see if anything interesting can be done. Is there even enough information for this to be do-able yet?
As the Lockheed Martin reactor will supposedly fit onto a truck, my guesstimate is 5..10mt with shielding, superconducting magnets and whatnot. If it is a thermal conversion model, then LM will need to use heat exchangers with gas turbines to get the electrical power out (makes it heavier again). My favorite, the direct conversion model with p-B11 fuel, would obviously be more compact. I'm worrying a bit about how to get rid of that immense waste heat in a vacuum, though. The radiators would glow red-hot, I guess. They could also use the photon pressure from the waste heat to accelerate.. .
Welcome back!
Total mass: 500mT
40MWe available to propulsion, 10MWe left in reserve/used/rest lost to heat
Assuming 70% propulsion system efficiency
28MW RF available for drive
Brady c TE mode @21.31 milliNewtons/kW performance propulsion system
Thrust at 28MW RF @0.02131N/kw=596N
Acceleration=0.00119200m/s^2
Velocity after 1 year=37.59km/s, 135327km/h, 84088.5mph
Displacement 3.96AU
I went further, considering that the end is bolted onto the cavity, what if it leaks RF? I modelled a narrow slice around the circumference of the cavity cone in the end plate, a variable sized opening but at the smallest resolution my computer will allow, 0.2% of the cavity large end radius.
The simulation detected Force/Power ranging from 2/c to 3/c.
That is two to three times the thrust of an ideal photon rocket. I think the cause of the force is evanescent waves escaping through the very narrow gap in the cavity base
Welcome back Aero!QuoteI went further, considering that the end is bolted onto the cavity, what if it leaks RF? I modelled a narrow slice around the circumference of the cavity cone in the end plate, a variable sized opening but at the smallest resolution my computer will allow, 0.2% of the cavity large end radius.
The simulation detected Force/Power ranging from 2/c to 3/c.
That is two to three times the thrust of an ideal photon rocket. I think the cause of the force is evanescent waves escaping through the very narrow gap in the cavity base
Isn't that about on a par with Woodward's device? The worst performer of the bunch?
... the radiation intensity approaches a kW/cm^2, or almost a MW/m^2.
QuoteTotal mass: 500mT
40MWe available to propulsion, 10MWe left in reserve/used/rest lost to heat
Assuming 70% propulsion system efficiency
28MW RF available for drive
Brady c TE mode @21.31 milliNewtons/kW performance propulsion system
Thrust at 28MW RF @0.02131N/kw=596N
Acceleration=0.00119200m/s^2
Velocity after 1 year=37.59km/s, 135327km/h, 84088.5mph
Displacement 3.96AU
So...if I am following this correctly, allowing for deceleration, a 3 year trip to Saturn, give or take a month? Versus a bit over 9 months for the Eagleworks proposal.
... the radiation intensity approaches a kW/cm^2, or almost a MW/m^2.
10,000 sq cm in one sq metre, not 1,000.
Cheers, Martin
And I think that producing thrust by making a resonant cavity and putting the end on losely is a lot easier than making a Woodward device. But that is not my point.Welcome back Aero!QuoteI went further, considering that the end is bolted onto the cavity, what if it leaks RF? I modelled a narrow slice around the circumference of the cavity cone in the end plate, a variable sized opening but at the smallest resolution my computer will allow, 0.2% of the cavity large end radius.
The simulation detected Force/Power ranging from 2/c to 3/c.
That is two to three times the thrust of an ideal photon rocket. I think the cause of the force is evanescent waves escaping through the very narrow gap in the cavity base
Isn't that about on a par with Woodward's device? The worst performer of the bunch?
I think 2x to 3x photon thrust is pretty much exactly the same number as the Woodward device, actually.
.....
Total mass: 500mT
40MWe available to propulsion, 10MWe left in reserve/used/rest lost to heat
Assuming 70% propulsion system efficiency
28MW RF available for drive
Brady c TE mode @21.31 milliNewtons/kW performance propulsion system
Thrust at 28MW RF @0.02131N/kw=596N
Acceleration=0.00119200m/s^2
Velocity after 1 year=37.59km/s, 135327km/h, 84088.5mph
Displacement 3.96AU
should examine specific earth departure and return techniques. Unconstrained Q-Ship spiral trajectories
could expose crewmembers to undesirable levels of radiation exposure due to the Van Allen radiation belts.
for any vehicle power P, the thrust that may be provided is:
ThrustForce = 2*Power/velocity
NOTE: The parameters considered by @Mulletron, under all cases considered (including Earth to Saturn in 757 days or 25.2 months) are safely under the "paradox condition" of Joosten/White. There is no paradox for these Mulletron Missions: the change in kinetic energy is less than the energy consumed
The "paradox condition" of Joosten/White for the parameters considered by @Mulletron occurs at 910 days (30.3 months of continuous acceleration).
The "paradox condition" is defined as the condition for which the change in kinetic energy of the spacecraft exceeds the input energy.
What is the evanescent wave effect? Is this a false positive (IE wouldn't work in space)?
QuoteNOTE: The parameters considered by @Mulletron, under all cases considered (including Earth to Saturn in 757 days or 25.2 months) are safely under the "paradox condition" of Joosten/White. There is no paradox for these Mulletron Missions: the change in kinetic energy is less than the energy consumed
The "paradox condition" of Joosten/White for the parameters considered by @Mulletron occurs at 910 days (30.3 months of continuous acceleration).
The "paradox condition" is defined as the condition for which the change in kinetic energy of the spacecraft exceeds the input energy.
Maybe not the brightest of questions, but could Doctor McCulloch's theory possibly resolve the paradox issue? Accelerate long enough, and inertial radiation becomes significant?
I don't think so. The paradox occurs under conditions of constant acceleration. Under constant acceleration, the Unruh radiation stays the same in McCulloch's theory.
The paradox occurs when the velocity equals or exceeds 2 times the Power Input divided by the thrust force.
No, Dr. White does not propose that the EM Drive ignores this energy constraint.QuoteI don't think so. The paradox occurs under conditions of constant acceleration. Under constant acceleration, the Unruh radiation stays the same in McCulloch's theory.
The paradox occurs when the velocity equals or exceeds 2 times the Power Input divided by the thrust force.
So...How much of the physics textbooks will need rewritten if this device ignores the paradox? (continues to accelerate with the velocity exceeding twice the power input divided by the thrust force).
Would that be Free Energy?
When this situation occurs, in order to ensure that the input energy is equal to the change in kinetic energy, the thrust to power performance will have to decrease
Just a thought, but the higher the Q, the narrower the bandwidth, and the Doppler shift due to actual acceleration (or velocity in the rest frame) would probably limit that amount by exceeding the bandwidth.
At constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's velocity never exceeds 2*Power/Thrust
What is the evanescent wave effect? Is this a false positive (IE wouldn't work in space)?
Evanescent waves are a solution to Maxwell's equation, commonly named the "near field." So no, it is not a false positive and yes, it should work in space.
At constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's velocity never exceeds 2*Power/Thrust
QuoteAt constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's velocity never exceeds 2*Power/Thrust
I was going to start a thread, but there is a photon rocket variant idea I have been batting around for a few months now:
take a long hollow cylinder, closed at one end, open on the other. Probably several hundred meters long, by three or four meters in diameter. Running the length of this cylinder, spaced at even intervals are low beams - probably no more than ten or twenty centimeters high. So the inner edge of the cylinder has...call it a dozen shallow troughs. At regular intervals - maybe a meter - these beams have specially designed reflective points. Open end of the cylinder, you have a powerful high frequency laser (or something emitting a focused photon beam) aimed at a 45 degree angle into each trough. One laser per trough, call it twelve total.
Now, a laser, like a military searchlight, is also a photon rocket.
Photons, as pointed out in the previous thread are durable little critters, and can bounce around a good 50,000+ times before going wherever it is expired photons go. And photons can transfer momentum with each bounce.
So, turn the lasers on. The initial 'thrust' is backward. Actually, 'backward and sideways' because of the angle.
That thrust gets negated at the first bounce point. Photons hit that (reflective) point, transfer momentum, and head over to the next bounce point, set at a 45 degree angle to the first.
At the second bounce point, the whole thing is moving forward. Repeat for the length of the cylinder. Because the photons are hitting at an angle, the cylinder might start rotating as well as moving forward, but I don't see that as a major issue. At the end of the cylinder, the photons hit a shaped surface and bounce back along the tubes center and out into space.
Did a bit of reading on laser propulsion systems. A Doctor Bae ran some laboratory tests on this: bouncing laser beams multiplied the 'thrust' by a factor of 3000+ - into EM Drive territory without the physics headache. He proposed two linked spacecraft, with laser beams between them, something NASA is supposed to be looking into for near earth applications. My idea is one spacecraft (the cylinder) and a multiplier of about 1500, if the cylinder is long enough. Not sure, but that's should be on a par with the Brady EM drive model.
Alter the angles a bit, test different lasers/emitters, might get a lot more work out of the photons, increasing thrust further.
Would this violate the paradox?
What is the evanescent wave effect? Is this a false positive (IE wouldn't work in space)?
Evanescent waves are a solution to Maxwell's equation, commonly named the "near field." So no, it is not a false positive and yes, it should work in space.
OK, so how does this handle the conservation of momentum issue if it's more efficient than a photon rocket? What's the "reaction"?
... snip ...
First, note that the evanescent wave (7) possesses longitudinal canonical momentum pOz∝kz>k, which exceeds the momentum of a plane wave with the same local intensity.
What is the evanescent wave effect? Is this a false positive (IE wouldn't work in space)?
Evanescent waves are a solution to Maxwell's equation, commonly named the "near field." So no, it is not a false positive and yes, it should work in space.
OK, so how does this handle the conservation of momentum issue if it's more efficient than a photon rocket? What's the "reaction"?
... snip ...
See this paper - Extraordinary momentum and spin in evanescent waves Middle of page 5.
http://arxiv.org/pdf/1308.0547.pdf (http://arxiv.org/pdf/1308.0547.pdf)
QuoteFirst, note that the evanescent wave (7) possesses longitudinal canonical momentum pOz∝kz>k, which exceeds the momentum of a plane wave with the same local intensity.
That's what led me to look in this direction. Evanescent waves exhibit unusual behavior. The answer to your question then is that the photon rocket is not the ultimate in efficiency. Make a photon rocket using evanescent wave photons and the efficiency will be higher.
... Maybe ... that is what we're all here to find out.
In relativity; coupling of gravity and electromagnetism is infinitesimal though. That's what got Martin Tajmar's experiment so much attention at first. It suggested gravity-EM coupling billions of times stronger than predicted by RT. and what he got was still extremely tiny too.
Of course later he attributed his results to air currents caused by his cryo-coolant sublimating and retracted his paper.
Parenthetically, Tajmar's general design was also used by Ning Li and Podkletnov but probably differed in the details of cooling and method of obtaining rotation and materials for the disks.
That branch (family?) of gravity-EM drive designs has had bad luck even though there may be something there. Tajmar retracted, Ning Li allegedly absconded with research funds, Podkletnov got the kook treatment and retreated to Russia where he continues to claim results.
EDIT: in other news a recent experiment designed to test spin gravity failed to detect any difference in gravitation effects on a particle with a zero spin value and a non zero spin value. fermion and bosons were used...
http://phys.org/news/2014-07-equivalence-principle-effects-spin-gravity-coupling.html
So the question remains: what balances the momentum change of an EM Drive accelerated by evanescent waves? Are you proposing an interaction with the Quantum Vacuum? or terms coupling electromagnetism with gravitational forces? or something else?No - I am proposing that electromagnetic wave momentum depends on group velocity, and that evanescent waves in these circumstances exhibit superluminal group velocity. Nothing is violated - wave momentum reacts against the base plate and energy is inductively drawn from the cavity.
So the question remains: what balances the momentum change of an EM Drive accelerated by evanescent waves? Are you proposing an interaction with the Quantum Vacuum? or terms coupling electromagnetism with gravitational forces? or something else?No - I am proposing that electromagnetic wave momentum depends on group velocity, and that evanescent waves in these circumstances exhibit superluminal group velocity. Nothing is violated - wave momentum reacts against the base plate and energy is inductively drawn from the cavity.
I'll challange you, Dr. Rodel, and Mathematica to demonstrate why/how the energy resolves from the subluminal velocity solution of wave equations. I can help you formulate the problem but we need independent confirmation and you have shown great capability with Mathematica. Do that and you will have solved the EM drive paradox.
So the question remains: what balances the momentum change of an EM Drive accelerated by evanescent waves? Are you proposing an interaction with the Quantum Vacuum? or terms coupling electromagnetism with gravitational forces? or something else?No - I am proposing that electromagnetic wave momentum depends on group velocity, and that evanescent waves in these circumstances exhibit superluminal group velocity. Nothing is violated - wave momentum reacts against the base plate and energy is inductively drawn from the cavity.
I'll challange you, Dr. Rodel, and Mathematica to demonstrate why/how the energy resolves from the subluminal velocity solution of wave equations. I can help you formulate the problem but we need independent confirmation and you have shown great capability with Mathematica. Do that and you will have solved the EM drive paradox.
But evanescent waves decay exponentially. If you enclose the whole device in a large (imaginary) box, everything coming out will be just regular plane waves with well-known momentum. So where's the extra momentum coming from?
David Hambling http://www.theguardian.com/profile/davidhambling
... Anyone heard anything? Do we know what Boeing did after testing the one Shawyer sent them? They say they are not working with him, but that doesn't rule out developing his technology.
Such work has evidently ceased. “Phantom Works is not working with Mr. Shawyer,” a Boeing representative says, adding that the company is no longer pursuing this avenue.Notice that Hambling disclosed not only that “Phantom Works is not working with Mr. Shawyer” but even more final , they added that "the company (Boeing) is no longer pursuing this avenue." From what Hambling wrote, it reads to me that Boeing Phantom Works is no longer pursuing this (EM Drive) avenue. Furthermore, given a previous arrangement between Boeing and Shawyer, it would be highly non-standard for Boeing to continue working on Shawyer's technology without an Intellectual Property arrangement with Shawyer that would allow this. And, if Boeing would have conducted their own independent microwave cavity EM Drive R&D work prior to the arrangement with Shawyer, it would not make Intellectual Property sense that Boeing would have entered into an arrangement with Shawyer, as large companies usually refuse to discuss inventions with outside inventors because such discussions and arrangements create Intellectual Property issues (Ford Motor Company has an old classic legal case on such IP questions, involving windshield wipers). Since Boeing is a very large public company with an extensive IP department, this implies that indeed "they are no longer pursuing this (EM Drive) avenue" at all, and if, hypothetically, Boeing were to conduct such development in the future, it would have to be a very different (for Intellectual Property purposes) engineering design than Shawyer's EM Drive.
It should read "At constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's (change in) velocity never exceeds 2*Power/Thrust"(I have accordingly added "change in" in the original entry).At constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's velocity never exceeds 2*Power/Thrust
Velocity measured relative to what?
for any vehicle power P, the thrust that may be provided is: ThrustForce = 2*Power/velocity
the transformation law shows that if energy is conserved in any one frame for a system which also conserves momentum, then the energy is conserved in another frame. This means that the total energy change is only meaningful for a system where no momentum flows in or out
3) You are correct, for the EM Drive to make any sense it implies having memory of its time-history in order to never exceed the critical velocity at which (for constant InputPower throughout the time period (delta time))
....
Note that in the above inequalities, the thrust/power is understood in the very particular way (in the case of the classical rocket) that the energy equivalent content of ejected mass is counted in "spent power" (otherwise a classical rocket obviously does much better than 1/c, ...)
....
http://www.technologyreview.com/view/426281/giant-casimir-effect-predicted-inside-metamaterials/
http://arxiv.org/abs/1110.1919
With this type of set up could you determine if the casimir effect is a suitable stunt double for exotic energy or mass for purposes of White's warp drive idea? :-\
Since the parameters of metamaterials we proposed are quite simple, this experiment would be easily implemented in laboratory
Has there been the least indication yet when we are too get some more results in relation to those who are experimenting in this area?
There is essentially a news blackout on the experimental side from NASA.
The problem is, if this drive really works, the defence implications are huge. Those in charge might feel it would not necessarily be a good idea to go public with it -- especially from the US perspective. Remember that 'Sputnik moment'?
Photons that travel in free space slower than the speed of light
That the speed of light in free space is constant is a cornerstone of modern physics. However, light beams have finite transverse size, which leads to a modification of their wavevectors resulting in a change to their phase and group velocities. We study the group velocity of single photons by measuring a change in their arrival time that results from changing the beam's transverse spatial structure. Using time-correlated photon pairs we show a reduction of the group velocity of photons in both a Bessel beam and photons in a focused Gaussian beam. In both cases, the delay is several microns over a propagation distance of the order of 1 m. Our work highlights that, even in free space, the invariance of the speed of light only applies to plane waves. Introducing spatial structure to an optical beam, even for a single photon, reduces the group velocity of the light by a readily measurable amount.
With my tinfoil hat on;) it's gone into the black and no more will be heard about it. Mind you surely the genie is out of the box now for it as an experiment able to be replicated including by other countries.
With my serious hat on perhaps you should ask on Talk-Polywell as there's probably people on there who might have an answer for you?
There is essentially a news blackout on the experimental side from NASA.
The problem is, if this drive really works, the defence implications are huge. Those in charge might feel it would not necessarily be a good idea to go public with it -- especially from the US perspective. Remember that 'Sputnik moment'?
....
the Brady results. The mode numbers they give have to be erroneous as they don't fit w/ the cavity frequency calculations. ...
...
Here I've tried to incorporate all 3 subscripts into the expression and eliminate some of my own confusion about the reported modes. ...I had a lot of trouble trying to figure out the X's from the "given" modes until I remembered they were in the cavity frequency formulas. That eliminated most of the possible modes...
So, using these to identify the frequencies, I chose:
Bradya => TM122 or TE022 X[sub m,n] = 7.02 p = 2
Bradyb => TE213 X[sub m,n] = 3.05 p = 3
Bradyc => TE222 X[sub m,n] = 6.71 p = 2
...
Bradya NT= 1.04e-4 vs 9.12e-5 Pwr= 16.9 Q=7320 TM122 or TE022
Bradyb NT= 4.80e-5 vs 5.01e-5 Pwr= 16.7 Q=18100 TE213
Bradyc NT= 4.78e-5 vs 5.54e-5 Pwr= 2.6 Q=22000 TE222
...
Poking around the internet, I ended up at this paper on Arxiv: http://arxiv.org/abs/1411.3987QuotePhotons that travel in free space slower than the speed of light
That the speed of light in free space is constant is a cornerstone of modern physics. However, light beams have finite transverse size, which leads to a modification of their wavevectors resulting in a change to their phase and group velocities. We study the group velocity of single photons by measuring a change in their arrival time that results from changing the beam's transverse spatial structure. Using time-correlated photon pairs we show a reduction of the group velocity of photons in both a Bessel beam and photons in a focused Gaussian beam. In both cases, the delay is several microns over a propagation distance of the order of 1 m. Our work highlights that, even in free space, the invariance of the speed of light only applies to plane waves. Introducing spatial structure to an optical beam, even for a single photon, reduces the group velocity of the light by a readily measurable amount.
What effect does reduced group velocity in free space have on the momentum of photons?
The speed of light in free space propagation is a fundamental quantity. It holds a pivotal
role in the foundations of relativity and field theory....
It has previously been experimentally established that single photons travel at the group
velocity. We have now shown that transverse structuring of the photon results in a
decrease in the group velocity along the axis of propagation. The effect can be derived
from a simple geometric argument, which is also supported by a rigorous calculation of
the harmonic average of the group velocity. Beyond light, the effect observed will have
applications to any wave theory, including sound waves and, potentially, gravitational
waves.
Oh well, time for me to make a spectacle of myself again...The fact that they do not sufficiently explore the complete mode shapes in the cavity does not mean that they proceeded from "badly flawed assumptions". That is too severe an assessment.
if I am following Notsosureofits and Rodal correctly, then...
1) the experimenters are proceeding from badly flawed assumptions about mode, among other things; and
2) their positive results come about through chance or design accident.
Quick question:Quick glance: I took a quick gander at them and they all look identical, insofar as being related to X'm,n and Xm,n (the zeros of the derivative of the Bessel function or the zeros of the Bessel function respectively) for TE and TM respectively. What difference do you see between them?
Did someone mention in the past that the equations at the Oracle are no good? Or were they good?
http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity
or are these good
Am I better off going with the Kwok slide 13?
http://www.engr.sjsu.edu/rkwok/EE172/Cavity_Resonator.pdf
or this guy's method?
http://www.chrislmueller.com/studies/Jackson8-6.pdf
Playing catch up here. This page is nifty. http://mathworld.wolfram.com/BesselFunctionZeros.html
...Good idea, I'm ready :-)
I think it might be time for a spaceflight application minute...
...A minor point. For further clarity you may want to include a prime symbol (or an apostrophe) on X
For TM modes, X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
...
...A minor point. For further clarity you may want to include a prime symbol (or an apostrophe) on X
For TM modes, X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
...
"for TE modes, X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function"
instead of
"for TE modes, X[subm,n] = the n-th zero of the derivative of the m-th Bessel function"
to differentiate X' (as used for the TE modes) from X (as used for the TM modes). :)
Space travel applications...
If applied, would 'Notsosureofit's mode calculations significantly help or hinder the 'Mulletron Mission to Saturn'?
Space travel applications...
If applied, would 'Notsosureofit's mode calculations significantly help or hinder the 'Mulletron Mission to Saturn'?
Might help if it could calculate an "optimum" cavity shape. Such has been done for acoustic cavity refrigerators, etc. What is the maximum asymmetric dispersion you can get ? What is the optimum frequency ? (and the highest Q, of course)
Then too, it's not yet apparent why this calculation works at all.
@RODAL
A. I'm still having conceptual difficulties w/ the mode numbers trying to resolve the waveguide vs cavity versions of this thing.
B. Don't have access to COMSOL anyway
C. Used square avg to get close to an equivalent vol cylinder
D. Didn't use included dielectric, but assumed it might change the res freq somewhat. Prob the biggest errors. (enough to change mode numbers?)
E. Sounds like what I wound up using
F. Nice !
G. Those still might not be the correct modes given that the dielectric is not taken into account along w/ the dimensional approximations. i didn't try all matches.
...snip...
...
For TM modes, X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
So, using these to identify the frequencies, I chose:
Bradya => TM122 or TE022 X[sub m,n] = 7.02 p = 2
Bradyb => TE213 X'[sub m,n] = 3.05 p = 3
Bradyc => TE222 X'[sub m,n] = 6.71 p = 2
....
QuoteAt constant input power, the thrust, and therefore the acceleration, must decrease with time, to ensure that the spacecraft's velocity never exceeds 2*Power/Thrust
I was going to start a thread, but there is a photon rocket variant idea I have been batting around for a few months now:
take a long hollow cylinder, closed at one end, open on the other. Probably several hundred meters long, by three or four meters in diameter. Running the length of this cylinder, spaced at even intervals are low beams - probably no more than ten or twenty centimeters high. So the inner edge of the cylinder has...call it a dozen shallow troughs. At regular intervals - maybe a meter - these beams have specially designed reflective points. Open end of the cylinder, you have a powerful high frequency laser (or something emitting a focused photon beam) aimed at a 45 degree angle into each trough. One laser per trough, call it twelve total.
Now, a laser, like a military searchlight, is also a photon rocket.
Photons, as pointed out in the previous thread are durable little critters, and can bounce around a good 50,000+ times before going wherever it is expired photons go. And photons can transfer momentum with each bounce.
So, turn the lasers on. The initial 'thrust' is backward. Actually, 'backward and sideways' because of the angle.
That thrust gets negated at the first bounce point. Photons hit that (reflective) point, transfer momentum, and head over to the next bounce point, set at a 45 degree angle to the first.
At the second bounce point, the whole thing is moving forward. Repeat for the length of the cylinder. Because the photons are hitting at an angle, the cylinder might start rotating as well as moving forward, but I don't see that as a major issue. At the end of the cylinder, the photons hit a shaped surface and bounce back along the tubes center and out into space.
Did a bit of reading on laser propulsion systems. A Doctor Bae ran some laboratory tests on this: bouncing laser beams multiplied the 'thrust' by a factor of 3000+ - into EM Drive territory without the physics headache. He proposed two linked spacecraft, with laser beams between them, something NASA is supposed to be looking into for near earth applications. My idea is one spacecraft (the cylinder) and a multiplier of about 1500, if the cylinder is long enough. Not sure, but that's should be on a par with the Brady EM drive model.
Alter the angles a bit, test different lasers/emitters, might get a lot more work out of the photons, increasing thrust further.
Would this violate the paradox?
You seem to misunderstand the fundamentals of mechanics.
If a photon hits a mirror at a 45 degree angle and reflects off it, the mirror will receive an impulse perpendicular to the plane of the mirror only. It will not be pushed in the direction of the other component of the photon at all.
It's not just with photons. If you have a billiard ball and you bounce it off another billiard ball that was stationary so that the original ball end up leaving at a 90 degree angle to its initial direction of travel, the other ball will end up traveling at a 45 degree angle to the path of the original ball.
It's non-intuitive because our intuition is shaped by friction tending to pull things along, but such friction is not a part of purely elastic collisions, and photons bouncing off mirrors are purely elastic.
So, every time your photon bounces off the wall, the momentum it imparts will only be to push outward perpendicular to the axis of the tube. And it will be cancelled by the next bounce off the opposite wall.
The only effect of the net momentum of the tube is the opposite of whatever momentum the photo has when it finally leaves the tube. Whatever it does as it bounces around in the tube will have no net effect.
...
For TM modes, X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
So, using these to identify the frequencies, I chose:
Bradya => TM122 or TE022 X[sub m,n] = 7.02 p = 2
Bradyb => TE213 X'[sub m,n] = 3.05 p = 3
Bradyc => TE222 X'[sub m,n] = 6.71 p = 2
....
...
TM111 gives me 1.03 GHz ditto for TE011
...
TM111 gives me 1.03 GHz ditto for TE011
...Are you thinking this way?
I'm thinking the volumetric radius might be the best choice as radius
R^2 = (a^2+a*b+b^2)/3
Havn't had time to try recalculations, but if you have Mathematica you can try lots
We are using different radii. ,,,I used Aero's and also Fornaro's dimensions. For example,
Ok...so if I am following the latest exchange correctly, then these devices dimensions MUST be in complete sync with the given frequency in order for them to work at all? Or do they just function very poorly if the match is not exact?
I also recollect long posts in the other thread about how difficult it was to attain and maintain the correct frequency - something about it shifting?
There is essentially a news blackout on the experimental side from NASA.
The problem is, if this drive really works, the defence implications are huge. Those in charge might feel it would not necessarily be a good idea to go public with it -- especially from the US perspective. Remember that 'Sputnik moment'?
...
TM111 gives me 1.03 GHz ditto for TE011
If, were one to use the diameter instead of the radius in the frequency equation one would obain:
...
TM111 gives me 1.03 GHz ditto for TE011
If, were one to use the diameter instead of the radius in the frequency equation one would obain:
You are exactly right, I've been (inadvertantly) calculating w/ DIAMETERS !
I've got to stop using Post-it notes !
...
Added: http://scitechdaily.com/way-self-propel-subatomic-particles-without-external-forces/
It turns out that this self-acceleration does not actually violate any physical laws — such as the conservation of momentum — because at the same time the particle is accelerating, it is also spreading out spatially in the opposite direction.
“The electron’s wave packet is not just accelerating, it’s also expanding,” Kaminer says, “so there is some part of it that compensates. It’s referred to as the tail of the wave packet, and it will go backward, so the total momentum will be conserved. There is another part of the wave packet that is paying the price for the main part’s acceleration.”
It turns out, according to further analysis, that this self-acceleration produces effects that are associated with relativity theory: It is a variation on the dilation of time and contraction of space, effects predicted by Albert Einstein to take place when objects move close to the speed of light. An example of this is Einstein’s famous twin paradox, in which a twin who travels at high speed in a rocket ages more slowly than another twin who remains on Earth.
I been in contact with NASA on this and the lack of direct response has been marked. They will talk about the warp drive and other work, but will not even mention the EmDrive in their replies. It's as though they cannot speak its name...I also have it from other sources that NASA have requested that they do not discuss NASA's work in this area. If you can find any official NASA public comment on anything related to their EmDrive work I will be impressed! It does look like a blackout to me.
If NASA really decides to go silent on this, that would be a strong indication that the effect is not only real, but imminently useful. For those in the administration that might feel going silent is the optimal approach, I would suggest to them otherwise. Attempting to impede and to cover such information in the age of the Internet is futile. Though it may slow the efforts within the U.S. to reproduce and harness the effect, this is a multi-national effort, and the advancement and evolution of our species will continue in its progression despite such efforts. To any and all leaders within NASA or other governmental organizations whose first reaction is to suppress, please consider that such an approach is very 20th century.
If NASA really decides to go silent on this, that would be a strong indication that the effect is not only real, but imminently useful. For those in the administration that might feel going silent is the optimal approach, I would suggest to them otherwise. Attempting to impede and to cover such information in the age of the Internet is futile. Though it may slow the efforts within the U.S. to reproduce and harness the effect, this is a multi-national effort, and the advancement and evolution of our species will continue in its progression despite such efforts. To any and all leaders within NASA or other governmental organizations whose first reaction is to suppress, please consider that such an approach is very 20th century.
Thinking about potential historic parallels, they ought to be seriously considering to avoid another Sputnik moment.
It is possible they would want to use it in military projects in the short term (endless autonomy/re-positioning satellites would revolutionize spy sats and anti-sat warfare).
But there is the Chinese interest in it too. If they verified it works, they could be already working in military applications, and probably on a few civil ones. Unlimited range space probes would be a very good publicity stunt for them, for proving their technical superiority.
Would you say it's a case of shutting the stable door after the horse has bolted?
So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?Would you say it's a case of shutting the stable door after the horse has bolted?
It probably is, but I don't think it would be an attempt at censorship by making all information about this a secret. That horse already left the stable, as you say.
In all probability (if they already know this exists and works outside of the public peer review process) they are trying to prevent the spread of sensitive "next step" information, allowing potential enemy powers to quickly develop the same technology, just by reading the same public reports we on the Internet do.
It's not the first time I have read people pleading for keeping the reports about Q-thruster technology a secret, because in case of being true, they would certainly be matters of national security.
Great ! In my 2 minutes at a time I'm off to figure out why df/c = the momentum, but in the accelerated frame of reference.
Added: http://scitechdaily.com/way-self-propel-subatomic-particles-without-external-forces/
"We find these shape-preserving Dirac wavefunctions to be part of a family of accelerating quantum particles, which includes massive/massless fermions/bosons of any spin."
It turns out that this self-acceleration does not actually violate any physical laws — such as the conservation of momentum — because at the same time the particle is accelerating, it is also spreading out spatially in the opposite direction.
“The electron’s wave packet is not just accelerating, it’s also expanding,” Kaminer says, “so there is some part of it that compensates. It’s referred to as the tail of the wave packet, and it will go backward, so the total momentum will be conserved. There is another part of the wave packet that is paying the price for the main part’s acceleration.”
It turns out, according to further analysis, that this self-acceleration produces effects that are associated with relativity theory: It is a variation on the dilation of time and contraction of space, effects predicted by Albert Einstein to take place when objects move close to the speed of light. An example of this is Einstein’s famous twin paradox, in which a twin who travels at high speed in a rocket ages more slowly than another twin who remains on Earth.
So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
It means an arms race, with the benefit being new tech making its way into the private sector eventually, as it usually does. I think our academic institutions and Nasa are being careful, either confirming a breakthrough or squashing a blunder.Quote from: wembleyThere is essentially a news blackout on the experimental side from NASA.
The problem is, if this drive really works, the defence implications are huge. Those in charge might feel it would not necessarily be a good idea to go public with it -- especially from the US perspective. Remember that 'Sputnik moment'?Quote from: Mulletron@wembley, do you have any specific info about why you think there is a news blackout?
Also, do you have any further verifiable information from this post: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1265607#msg1265607 stating Shawyer stopped using a dielectric section?Quote from: wembleyI been in contact with NASA on this and the lack of direct response has been marked. They will talk about the warp drive and other work, but will not even mention the EmDrive in their replies. It's as though they cannot speak its name...I also have it from other sources that NASA have requested that they do not discuss NASA's work in this area. If you can find any official NASA public comment on anything related to their EmDrive work I will be impressed! It does look like a blackout to me.
The info about Shawyer not using dielectric section was in an email from the man himself.
Interesting to hear.
What happens if another country wheels a drive out, haven't others been working in this area?
It could be that the decision, assuming it does work, on what to say and what not to say has gone right the way up the chain of command literally to the very top and in the meantime the blackout is put in place.So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
That or someone on NASA became aware of the potential huge embarrassment this represents, and told all the guys off and ordered them to pretend it never happened.
But as H. White et al seem to be still working at NASA, I somewhat doubt it's a case of disowning a blunder. Or at least, I hope so.
Yep you nailed it....... This is TOO public so the truth will have to come and come soon. This isn't your typical flash in the pan news story. The potential worth of this kind of discovery is priceless, on the order of Newton and Einstein. Or just a big series of unfortunate mistakes.So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
That or someone on NASA became aware of the potential huge embarrassment this represents, and told all the guys off and ordered them to pretend it never happened.
But as H. White et al seem to be still working at NASA, I somewhat doubt it's a case of disowning a blunder. Or at least, I hope so.
only if this thing can go hyper velocity or relativistic velocity in a flight profile that makes it useful as a weapon of mass destruction. so far the most optimistic projection by Dr White would make it have to fly for over twelve days and then turn around and come back to make it into a WMD. that's not really a realistic flight profile for a sneak attack weapon.It could be that the decision, assuming it does work, on what to say and what not to say has gone right the way up the chain of command literally to the very top and in the meantime the blackout is put in place.So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
That or someone on NASA became aware of the potential huge embarrassment this represents, and told all the guys off and ordered them to pretend it never happened.
But as H. White et al seem to be still working at NASA, I somewhat doubt it's a case of disowning a blunder. Or at least, I hope so.
This might sound odd but perhaps it's for the best that for now this stays outside of the mainstream of public awareness.
It could be that the decision, assuming it does work, on what to say and what not to say has gone right the way up the chain of command literally to the very top and in the meantime the blackout is put in place.
This might sound odd but perhaps it's for the best that for now this stays outside of the mainstream of public awareness.
only if this thing can go hyper velocity or relativistic velocity in a flight profile that makes it useful as a weapon of mass destruction. so far the most optimistic projection by Dr White would make it have to fly for over twelve days and then turn around and come back to make it into a WMD. that's not really a realistic flight profile for a sneak attack weapon.It could be that the decision, assuming it does work, on what to say and what not to say has gone right the way up the chain of command literally to the very top and in the meantime the blackout is put in place.So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
That or someone on NASA became aware of the potential huge embarrassment this represents, and told all the guys off and ordered them to pretend it never happened.
But as H. White et al seem to be still working at NASA, I somewhat doubt it's a case of disowning a blunder. Or at least, I hope so.
This might sound odd but perhaps it's for the best that for now this stays outside of the mainstream of public awareness.
Well, if it works, then parking a second strike kinetic weapon package at earth-sun L4/L5 is feasible (hell, earth-moon L2 would make the package immune from terrestrial laser attack). This IS the US military we're talking about, who dreamed up Project Horizon to bomb the earth from a moonbase, and that was with a 3 day lag using chemical propulsion. Added fun is using an expendable electrodynamic tether as a power source as you approach earth, since you only need high relative speed at impact (drop into a counterorbit).
Actually, I wonder how applicable that would be, using an ED tether as a power source for orbital capture ops, as a possible alternative to aerocapture...
Thus the geopolitical impact of this technology being real is evident if you think about it a little.
In the short term, endless autonomy in terms of thrust and re-positioning would completely change the rules of engagement for spy satellites and anti-satellite weapons. You can have limitless observation capabilities and limitless loitering, following, attacking (and dodging) capabilities too. War bots in orbit could finally fulfill Ronald Reagan's dreams for war in space. And not just that.
Even very slight accelerations (as reported by Brady, White et al) with preposterously limited top speeds, they can serve for pushing and placing dormant kinetic bombs far away from Earth, beyond the reach of any feasible enemy's detection or attack; and they would also serve for bringing them back to Earth at their maker's command, for landing at any desired spot, producing nearly any desired amount of damage.
While all of us sit here on Earth, sharing the same biosphere and the same rock under our feet, the development and availability of that weaponry would result in an aggravated and somewhat madder version of MAD. Because even if you could be attacked in secret from any direction, you can very well threaten to respond by attacking all your potential enemies with nuclear or kinetic nastiness, ruining the game and the fun for all your potential attackers.
But if you have parties/adversaries living in space, could you threaten to crack all the planets in the Solar System?, or all the artificial habitats floating in the space between?
Removing the speed limitations (thus conservation of energy) only makes things worse, making it feasible to have interstellar adversaries sending relativistic missiles to you. Those have no way to be stopped and even less, any way to provide adequate or proportionate response (you and all around you sharing the same planet would simply be dead).
So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
...Rockets respect conservation of momentum and energy by losing mass (and thus energy) in greater amounts than they gain by expelling that mass. These things don't have any clear way to remember how much energy they have spent, and what relative maximum velocity they can reach in order to not be "overunity"....
So does that mean we shouldn't except to hear anything more from the US on this & if that's the case what does that mean for civil applications?
I don't believe they can prevent any public disclosure of undeniably working prototypes by the Chinese, in a few years (or months). So they probably are just buying some time for having a working version on our side by then.
The Chinese will not go public. They have had a fairly tight clampdown for a couple of years now, with the only evidence being odd scientific papers. They don't want anyone else getting a lead on them either.
Really hoping that discussing such subjective political prospects and other implications of an as yet very theoretical space propulsion technology, is not going to get this thread locked for good..1) As explained here http://forum.nasaspaceflight.com/index.php?topic=29276.msg1301657#msg1301657, the previous long thread (which due to its extreme length would have been eventually locked to start a new thread anyway) was locked because of personal attacks and "stupid" and "pointless" posts "that did not feel like this site's subject matter." Specifically, posts (sometimes involving ad hominem attacks) dealing with Mach-Effect Piezoelectric experiments and theory (which already had dedicated threads to deal specifically with that topic) instead of the thread's subject: (Microwave ) EM Drive developments.
@Rodal tested in the UK, never knew that?Isn't Shawyer a UK native?
Who was carrying out those experiments?
@Rodal tested in the UK, never knew that?
Who was carrying out those experiments?
why shouldn't political ramifications of (Microwave) EM Drive space flight applications be discussed as well?I don't mind them myself. But I got the possibly mistaken impression (e.g. people actually asking for this to be locked even after thread v.2) that they put the discussion thread too close to or beyond this website's tolerances. My bad.
Happy to hear that you share our excitement of the potential of propellant-less space-propulsion technology :)why shouldn't political ramifications of (Microwave) EM Drive space flight applications be discussed as well?I don't mind them myself. But I got the possibly mistaken impression (e.g. people actually asking for this to be locked even after thread v.2) that they put the discussion thread too close to or beyond this website's tolerances. My bad.
Seeing such a thorough crunching thru the uncertainties of such an advanced and frankly just plain cool potential technology, IMHO is too excellent to lose. Even if EM Drives all turn out to be nothing, the process of making sense of it as detailed in these two threads is exemplary.
....Meep (an acronym for MIT Electromagnetic Equation Propagation) solves the Maxwell partial differential equations with the old Finite Difference numerical technique (developed decades before the Finite Element Method or the Boundary Element Method and other numerical techniques), albeit with an interesting implementation (and it is free, of course).
I would be curious to know if anyone can explain why the difference between the Wikipedia formula calculation of resonant frequency and the resonant frequency obtained by integrating Maxwell's equations in the time domain then doing Fourier analysis to calculate the resonant frequencies. In a nutshell, meep ...
Lightly following this thread but you folks are veering into territory I DO actually understand and I felt the need to correct some misconceptions.
Why is there the "assumption" that no matter how much (or little) an operational EM-Drive would generate it would be of military/geo-political value beyond, say, extending the service life of spy, communications, etc satellites? That it provides for greatly enhanced (or even practical) kinetic bombardment weapons? That it has some sort of huge military purpose that will ignite an arms race?
Really? No. Only if it has enough thrust to power an aircraft with a reasonable (turbine-generator) amount of power and is more efficent AND more powerful than current jet or rocket engines. Otherwise its simply a low-thrust station keeping and manuever system with a long service life :)
A thrust of 0.09lb to 0.9lb per KW as noted in the cited paper isn't that great really. Again the main advantge is you don't have to carry propellant/reaction mass. The main "geopolitical" ramification of the EM-Drive would be that satellite servicing is going to look a lot LESS attractive since with it you'd (supposedly) never have to fill up maneuvering system every again which was the major driver for that concept. :)
Hidden "Rods-From-Gods" in deep space ready to rain down on anyone, anywhere and "undetectable" due to the EM-Drive? Uh, NO just no.
First of all: There is no "stealth" in space. Period.
http://www.projectrho.com/public_html/rocket/spacewardetect.php
Your rod carrier is going to be spotted and tracked. The EM-Drive requires power, which is going to have heat that is going to have to be rejected, which is going to be "visible" to anyone looking in the right direction. The EM-Drive itself (according to one post above) "emits" radiation which can be detected with the right sensor set up. And lastly you CAN see objects in space if you look carefully enough. Even if you used solar panels to provide the power for the EM-Drive they are going to "reflect" some of the energy they recieve AND they are going to be sources of waste heat for the energy they absorb but do not use.
I wonder if anyone has pointed out that IF this "works" the way it would seem to what they've invented is basically the "Space:1889" Ether Propeller :)
Randy
http://en.wikipedia.org/wiki/Space:_1889
(http://upload.wikimedia.org/wikipedia/en/thumb/a/af/Space1889rpg.jpg/250px-Space1889rpg.jpg)
I don't know Randy. All the talk about Dark Energy, Dark Matter and Quantum Vacume are starting to sound a lot like the Aether concept!
I guess everything old is new again.
But is it the Edison, Zepplin, or Armstrong type? :)(http://ourworlds.topcities.com/space1889/ships/enterprise-side.gif)
The first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the waveguide. It is zero for modes in which there is no variation in the circumferential direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes).
The third subscript (p) is the longitudinal mode number. It indicates the number of full-wave patterns along the longitudinal length of the waveguide. It is zero for modes in which there is no variation in the longitudinal direction.
....Please provide the convergence study you have done, to analyze the convergence rate of your Meep calculation. I can't help you without seeing, and thus being able to analyze, the convergence study data.
I did double check everything as you advised and there does not seem to be anything wrong with my meep simulation.....
....Incorrect dimensioning is one of several kinds of numerical simulation errors possible.
So the cavity does not resonate at 2.45 GHz and therefore my dimensions must be wrong.
....
Here are my results.
Resolution number of time steps resonant frequency Q error
1 2 none detected
2 4 none detected
3 6 none detected
4 8 none detected
5 10 1.84921E+009 negative 2 e-4
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
80 160 1.86992E+009 ~ 300 13 e-4
160 320 1.87042E+009 ~ 80 47 e-4
The detected frequency bounces around consistently with the error which can be taken as estimating the number of significant digits of the frequency detected.
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
....
.. I am setting my simulation in 2-D, running in 64-bit single precision....Just to be speaking the same language, are you really using 64-bit: Double Precision as defined by the IEEE 754 standard ?
.....
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
I would seriously like to know how to properly design a resonant cavity for a selected resonant mode. I can tinker with the dimensions in meep and get higher quality factors, but that is not very efficient and forces me to guess the mode by looking at images of the wave pattern.
Ok, I did run it again with bandwidth = 0.2 * Drive frequency, for cases up to resolution of 80, but I didn't get anything. Once I narrow the bandwidth to exclude the resonant frequency at 1.87 GHz, there are no resonances within the bandwidth......
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
I would seriously like to know how to properly design a resonant cavity for a selected resonant mode. I can tinker with the dimensions in meep and get higher quality factors, but that is not very efficient and forces me to guess the mode by looking at images of the wave pattern.
What did you use for the bandwidth source around the frequency of interest (Drive frequency 2.45 E+9 Hz)?
Could you try running all these cases again, everything the same as before except with a significantly narrower bandwidth source around the frequency of interest ? . Reportedly harminv does a better job the narrower the source is around the frequency of interest .
Ok, I did run it again with bandwidth = 0.2 * Drive frequency, for cases up to resolution of 80, but I didn't get anything. Once I narrow the bandwidth to exclude the resonant frequency at 1.87 GHz, there are no resonances within the bandwidth......
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
I would seriously like to know how to properly design a resonant cavity for a selected resonant mode. I can tinker with the dimensions in meep and get higher quality factors, but that is not very efficient and forces me to guess the mode by looking at images of the wave pattern.
What did you use for the bandwidth source around the frequency of interest (Drive frequency 2.45 E+9 Hz)?
Could you try running all these cases again, everything the same as before except with a significantly narrower bandwidth source around the frequency of interest ? . Reportedly harminv does a better job the narrower the source is around the frequency of interest .
Harminv does work better at identifying the resonant frequency with narrower bandwidth, when the frequency is within the bandwidth. I set the drive frequency to 1.873 GHz, narrowed the bandwidth to 0.07 * frequency and got this:
frequency Quality factor error
1,873,339,229.3075 Hz 18,325,307.0778158 1.673972608680621e-7+0.0i
As you can see the quality factor is much higher and the processing error is much lower. The only problem is that it is not the frequency I had hoped for.
I did some further searching and found two things.
1 - The value of the J'0(1) Bessel function = 1.8411837813 which agrees with the number we have.
2 - Meep doesn't actually excite the cavity with Gaussian noise, rather it uses the derivative of a Gaussian signal, whatever that means.
I really don't think this particular problem is in the meep software. As I wrote before, I searched the discussion list, which goes back at least 8 years, and there is no mention of this particular problem. If it were in meep, some user would have encountered it long ago. A 25% discrepancy is hard to overlook. There is a chance that it is in my general understanding of how to model using meep, but my knowledge of meep is far superior to my knowledge of resonant cavity design so using Occam's razor, it is most likely that my cavity design is the problem.
Dr. Rodal, I really appreciate your efforts on my behalf. I will continue to look into the details of resonant cavity design. Maybe it has something to do with the cavity length. But actually, that doesn't seem very likely at all. What do you know about Gaussian noise derivatives and could that be a simple frequency correction? But, when generated with a continuous wave at 2.45 GHz, the field images don't show any resonance.
@RodelQuoteThe first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the waveguide. It is zero for modes in which there is no variation in the circumferential direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes).
The third subscript (p) is the longitudinal mode number. It indicates the number of full-wave patterns along the longitudinal length of the waveguide. It is zero for modes in which there is no variation in the longitudinal direction.
I did double check everything as you advised and there does not seem to be anything wrong with my meep simulation. Neither could I find any questions related to my problem on the Internet. That leads me to think that my problem is still my understanding of mode shapes and cavity dimensions. I thought I had TE1,1, but from the above, for the mode to be TE 1,1, the cavity radius needs to be 1/4 wavelength and the circumference should support 1 full wave pattern. The wavelength for 2.45 GHz is 0.1223642686 in vacuum. So, for the vacuum filled cavity to resonate at 2.45 GHz in the TE 1,1 mode the radius needs to be 0.0305910671 meters. But simply plugging that radius into the formula calculates a resonance frequency of ~2.92GHz in air. So it seems evident that I am still confused about modes and use of the formula to calculate resonance frequencies. Would you lead me through the example of a resonant cavity dimensions for 2.45 GHz resonance?
I also note that driving the cavity from my previous post at 2.45 GHz, R = 0.0377449, there is no sign of resonance in the field images. So the cavity does not resonate at 2.45 GHz and therefore my dimensions must be wrong.
NASA plans to upgrade their equipment to higher power levels, use vacuum-capable RF amplifiers with power ranges of up to 125 W, and design a new tapered cavity analytically expected to produce thrust in the 0.1 N/kW range. Then, the test article will be shipped to other laboratories for independent verification and continued evaluations of the technology, at Glenn Research Center, the Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory.
....As far as "m" goes, I don't see any discrepancy whatsoever. They all agree:
First here's what I have about mode numbering from various sources:
ME from thread 1: T(MorE)mnp. m is the # of 1/2 wavelengths around a half circumference...
Navy Neets mod 11 (screenshot below): The first subscript indicates the number of full-wave patterns around the circumference of the waveguide....
Oracle: http://en.wikipedia.org/wiki/Transverse_mode In circular waveguides, circular modes exist and here m is the number of half-wavelengths along a half-circumference....
Rodal: The first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the waveguide.
....
So there is conflicting information. Rodal and the Navy agree, the oracle and me are different....
As far as n or p go, I'm not even going to look at them until I get some feedback about the m discrepancies....
We differ in the full mnp description. Look at n. M is the same between us, but the coke can example has me wondering.
As far as n or p go, I'm not even going to look at them until I get some feedback about the m discrepancies....
....
Here are my results.
Resolution number of time steps resonant frequency Q error
1 2 none detected
2 4 none detected
3 6 none detected
4 8 none detected
5 10 1.84921E+009 negative 2 e-4
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
80 160 1.86992E+009 ~ 300 13 e-4
160 320 1.87042E+009 ~ 80 47 e-4
The detected frequency bounces around consistently with the error which can be taken as estimating the number of significant digits of the frequency detected.
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
....
So is the m resolved because the KWOK modes were so close but no cigar together? That's my hunch, but I want verify before I let it go. Lesson learned.....don't round off when it comes to mode shapes then?I need to take care of $ paying work first :). As I get time, my first priority is to deal with aero's problem (it came first :) ) and after that I'll take a thorough look at the numbers in KWOK and the "n" and "p" issue you brought up. Sorry I don't want to give you an answer as an immediate reflex. I want to give you a thoughtful answer. I need some time to go carefully over these issues :).
Drive frequency 2.45 E+9 Hz, so wavelength = 0.1223642686 meters.....
Here are my results.
Resolution number of time steps resonant frequency Q error
1 2 none detected
2 4 none detected
3 6 none detected
4 8 none detected
5 10 1.84921E+009 negative 2 e-4
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
80 160 1.86992E+009 ~ 300 13 e-4
160 320 1.87042E+009 ~ 80 47 e-4
The detected frequency bounces around consistently with the error which can be taken as estimating the number of significant digits of the frequency detected.
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
....
Aero, please tell me again exactly what is the actual numerical value that you actually inputed into MEEP for the drive frequency for the above calculations. What is the number that you inputed into MEEP.
Drive frequency 2.45 E+9 Hz, so wavelength = 0.1223642686 meters.
Geometry actual inside dimensions L= 0.1223642686, Dia = 0.0754898000 meters air filled cylindrical cavity with no dielectric. I am ignoring the difference between speed of light in air and vacuum.
I copied those numbers straight from the control file. This is what I used.
Drive frequency 2.45 E+9 Hz, so wavelength = 0.1223642686 meters.....
Here are my results.
Resolution number of time steps resonant frequency Q error
1 2 none detected
2 4 none detected
3 6 none detected
4 8 none detected
5 10 1.84921E+009 negative 2 e-4
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
80 160 1.86992E+009 ~ 300 13 e-4
160 320 1.87042E+009 ~ 80 47 e-4
The detected frequency bounces around consistently with the error which can be taken as estimating the number of significant digits of the frequency detected.
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
....
Aero, please tell me again exactly what is the actual numerical value that you actually inputed into MEEP for the drive frequency for the above calculations. What is the number that you inputed into MEEP.
Geometry actual inside dimensions L= 0.1223642686, Dia = 0.0754898000 meters air filled cylindrical cavity with no dielectric. I am ignoring the difference between speed of light in air and vacuum.
I copied those numbers straight from the control file. This is what I used.
Drive frequency 2.45 E+9 Hz, so wavelength = 0.1223642686 meters.....
Here are my results.
Resolution number of time steps resonant frequency Q error
1 2 none detected
2 4 none detected
3 6 none detected
4 8 none detected
5 10 1.84921E+009 negative 2 e-4
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
80 160 1.86992E+009 ~ 300 13 e-4
160 320 1.87042E+009 ~ 80 47 e-4
The detected frequency bounces around consistently with the error which can be taken as estimating the number of significant digits of the frequency detected.
The quality is very low. I take that to be a result of the cavity dimensions being incorrect for the resonant frequency detected as they are also incorrect for the drive frequency.
....
Aero, please tell me again exactly what is the actual numerical value that you actually inputed into MEEP for the drive frequency for the above calculations. What is the number that you inputed into MEEP.
Geometry actual inside dimensions L= 0.1223642686, Dia = 0.0754898000 meters air filled cylindrical cavity with no dielectric. I am ignoring the difference between speed of light in air and vacuum.
I copied those numbers straight from the control file. This is what I used.
Moreover, since c = 1 in Meep units, a (or a / c) is our unit of time as well. In particular, the frequency f in Meep (corresponding to a time dependence e − i2πft) is always specified in units of c / a
...I don't follow the need for this "scale factor" (Scale factor, 0.01) you are using. It may unnecessarily complicate things -- I would not use it until you have exactly matched the exact solution.
Geometry actual inside dimensions L= 0.1223642686, Dia = 0.0754898000 meters air filled cylindrical cavity with no dielectric. I am ignoring the difference between speed of light in air and vacuum.
Scale factor, 0.01, but is a parameter to adjust
The above gives geometry simulation dimensions in scaled units = 012.23642686, 007.54898000
...
susceptibility
Parent class for various dispersive susceptibility terms, parameterized by an anisotropic amplitude σ (see Material dispersion in Meep):
sigma [number]
The scale factor σ.
In particular, because Maxwell's equations are scale invariant (multiplying the sizes of everything by 10 just divides the corresponding solution frequencies by 10), it is convenient in electromagnetic problems to choose scale-invariant units (see our online textbook, ch. 2). That means that we pick some characteristic lengthscale in the system, a, and use that as our unit of distance.
The scale factor, also known as characteristic length - "we pick some characteristic lengthscale in the system, a, and use that as our unit of distance." Or, more detailed, from "Units in Meep" here; http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction (http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction)QuoteIn particular, because Maxwell's equations are scale invariant (multiplying the sizes of everything by 10 just divides the corresponding solution frequencies by 10), it is convenient in electromagnetic problems to choose scale-invariant units (see our online textbook, ch. 2). That means that we pick some characteristic lengthscale in the system, a, and use that as our unit of distance.
The scale factor, also known as characteristic length - "we pick some characteristic lengthscale in the system, a, and use that as our unit of distance." Or, more detailed, from "Units in Meep" here; http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction (http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction)QuoteIn particular, because Maxwell's equations are scale invariant (multiplying the sizes of everything by 10 just divides the corresponding solution frequencies by 10), it is convenient in electromagnetic problems to choose scale-invariant units (see our online textbook, ch. 2). That means that we pick some characteristic lengthscale in the system, a, and use that as our unit of distance.
It unnecessarily complicates things at this point, it presents extra problems of interpretation -- I would not use it until you have exactly matched the exact solution. If you must, use Scale Factor =1, for the time being: if you input to MEEP L= 0.1223642686 (meters), Dia = 0.0754898000 (meters), then the MEEP frequency should be as per my previous post in 8.77064 1/meters units. (And you should interpret the output in 1/meters frequency units as well)
If instead you input L = 12.23642686, D= 7.54898000 you are effectively using centimeters as your input unit of length, and therefore your MEEP frequency should be input in 1/cm units, giving MEEP Frequency = 0.0877064 1/centimeter, and you would have to multiply the output frequencies by cVacuum = 29979245800 centimeter/second to express the output in Hz. Unnecessarily messy at this point.
The scale factor, also known as characteristic length - "we pick some characteristic lengthscale in the system, a, and use that as our unit of distance." Or, more detailed, from "Units in Meep" here; http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction (http://ab-initio.mit.edu/wiki/index.php/Meep_Introduction)QuoteIn particular, because Maxwell's equations are scale invariant (multiplying the sizes of everything by 10 just divides the corresponding solution frequencies by 10), it is convenient in electromagnetic problems to choose scale-invariant units (see our online textbook, ch. 2). That means that we pick some characteristic lengthscale in the system, a, and use that as our unit of distance.
It unnecessarily complicates things at this point, it presents extra problems of interpretation -- I would not use it until you have exactly matched the exact solution. If you must, use Scale Factor =1, for the time being: if you input to MEEP L= 0.1223642686 (meters), Dia = 0.0754898000 (meters), then the MEEP frequency should be as per my previous post in 8.77064 1/meters units. (And you should interpret the output in 1/meters frequency units as well)
If instead you input L = 12.23642686, D= 7.54898000 you are effectively using centimeters as your input unit of length, and therefore your MEEP frequency should be input in 1/cm units, giving MEEP Frequency = 0.0877064 1/centimeter, and you would have to multiply the output frequencies by cVacuum = 29979245800 centimeter/second to express the output in Hz. Unnecessarily messy at this point.
It doesn't work that way. I input units in meters, and the scale factor. The input is scaled, then the output that I gave you is "unscaled" to be in SI units. But yes, I can run meep with a scale factor of 1. It gives the same answers but takes more CPU so the runs are longer. Not to bad for this simple 1D calibration problem though.
Here is an example using resolution = 1200, which is quite low resolution.
frequency quality factor error
1.86060E+009 37934.0653626318 7.872026063658947e-6+0.0i
Had I used this scale factor and geometry to generate 2D images of the developing fields, it would take about 12 hours computer run time, per meep estimate. Generating those images using a scale factor of 0.01 takes about 45 minutes as I recall.
No it's not, that resolution is likely somewhere between these lines.
10 20 1.85128E+009 negative 2 e-4
20 40 1.86441E+009 ~ 500 6 e-4
40 80 1.87262E+009 ~ 1200 3 e-4
that I posted 2 pages back.
And no I don't. The meep input frequency must be in the same dimensional units as the geometry, I use SI units.
I have made progress though. Using the frequency formula to adjust cavity length so that the formula gave 2.45GHz, required a cavity length about 0.0965 meters. Iteratively running meep and adjusting the cavity length to force resonance at 2.45 GHZ independently produced a cavity length of 0.0936 meters.
I emphasize that I worked those problems independently of each other so the fact that they are in near agreement is telling. I would like to find a combination length and radius that would give the frequency without the length being so close to 3/4 wavelength. In fact, I would like for the length to be exactly one wavelength and for which I knew the mode. TE 1,1,1 would be good, but TE 1,4,1 might also work. Maybe now that I have found one solution, I can find more solutions.
My input frequency is converted to meep units in the control file, meep frequency = 0.08172320332354725. That is scaled by the 0.01 factor. But that is not an input. The input is frequency in SI units. The conversion is scale factor/c so I guess the units would be 1/meter internally.
It's difficult for me to come up with 8.77064 1/meters though. That is your 2.63 GHz number and I've not seen it in any of my meep runs that I recall.
....
I want to point out a discrepancy I found. Perhaps I'm the discrepancy, because I don't agree with my old post or any of the other sources, which is highly unlikely.
First here's what I have about mode numbering from various sources:
ME from thread 1: T(MorE)mnp. m is the # of 1/2 wavelengths around a half circumference, n is the # of 1/2 wavelengths across a radius, p is the # of 1/2 wavelengths of length of the cavity.
Navy Neets mod 11 (screenshot below): The first subscript indicates the number of full-wave patterns around the circumference of the waveguide. The second subscript indicates the number of half-wave patterns across the diameter.........(p left out).
Oracle: http://en.wikipedia.org/wiki/Transverse_mode In circular waveguides, circular modes exist and here m is the number of half-wavelengths along a half-circumference and n is the number of half-wavelengths along a radius.......(p left out).
Rodal: The first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the waveguide.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The third subscript (p) is the longitudinal mode number. It indicates the number of full-wave patterns along the longitudinal length of the waveguide.
So there is conflicting information. Rodal and the Navy agree, the oracle and me are different. I'll see if I can clear it up.....and find deal here.
Using the coke can example from http://www.engr.sjsu.edu/rkwok/EE172/Cavity_Resonator.pdf slide 17, for a radius of 1.25"(or diameter of 2.5"), depth of 5". This comes out to a TE111 f,res of 3.01ghz, which gives me a wavelength of 3.923". So first, to test the first subscript m, the circumference of a circle with r 1.25" is 7.85". 7.85"inch is 2 wavelengths @3.01ghz.
So it appears that m should be the # of full wavelengths around half a circumference.
or
If you don't do any rounding with the coke can example, @3.01ghz you get 3.923928113636958 inches, multiply that by 2 you get 7.847856227273916 inches, which is just shy of the calculated circumference of 7.85, which technically is not a FULL cycle of 2 wavelengths. Which means this example sits on the edge of TE111 and TE211. Technically that 0 wasn't crossed yet.
So is that the answer? FULL wavelengths must be counted, the rest is dropped? Meaning if you go around 2.6 times for example, you just get an m of 2?
This is important because soon I'm going to be cutting copper shapes and making stupid mistakes can be very expensive.
I've found fault with the Navy references before on other things, and we all know that everything on the Oracle needs to be verified, and I'm frequently wrong, but Rodal is usually right. So what's going on there?
As far as n or p go, I'm not even going to look at them until I get some feedback about the m discrepancies. I just want to clear this up. I don't mind getting egg on my face.
Break:
You know, I think this got overlooked: "We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust."
I got a lot of grief before for my approach to deriving the cavity dimensions (starting with the 6.25 inch small end, using the dimensions of the PE discs from 14 of Brady et al Anomalous thust...., but I think those dimensions, (see screenshot below) are exactly spot on and here's empirical proof. So my calculated cavity length in Autocad after scaling based on 6.25inch small ends size, was 10.88". If you look at the frequency of 2168mhz, you'll find the wavelength is 5.4479". Take two wavelengths of this, you'll arrive at 10.8958, my cavity length was 10.88". Converted to meters, it is:
Dsmall=0.15875m (0.159m)
Dlarge=0.30098m (0.3m) amazingly round number
Length=0.27637m (.276m)
The first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the cylindrical cavity. It is zero for modes in which there is no variation in the circumferential direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes).
The third subscript (p) is the longitudinal mode number. It indicates the number offull-wave patterns along the longitudinal length of the waveguide. It is zero for modes in which there is no variation in the longitudinal direction.
The naturally conforming reflecting end for a conical Wave-guide is such a sphere, just as the conforming end for a cylindrical wave-guide is a flat plate. It is believed that the reason that the spherical end is superior is that fewer higher order modes need be excited in reflection from such an end than from a fiat end, or that the degree of such excitation is less. It is further believed that higher order modes can be excited in the large end of the resonator which are undetectable through the input and output structures located at the small end, where these modes are below cut-off. They are however, detectable in that such coupling between modes may cause a reduction in the Q factor of the desired mode.
Since the curvature of the end plate cannot be altered as the resonator is tuned, the curvature of this end plate is also a factor which does not scale during the tuning of the cavity. It thus will cause slight perturbation of the modes. It appears to be possible to employ this perturbation to offset the effects of the perturbation due to the gap around the plunger, which also varies during tuning. This generally requires empirical adjustment of the plunger radius of curvature until the Q factor remains good over the tuning range.
As a feature of the third concept, an absorber is provided in the back cavity, behind the plunger or base plate and around the rim of the base plate. Successful use has also been made in experiment of grooves made in the face of the plate and partially filled with absorbing material.
Thank you @Mulletron for looking at this discrepancy, which enables me to correct this mistake: :)
My description of the quantum mode number "p" for the longitudinal direction of a cylindrical cavity in http://forum.nasaspaceflight.com/index.php?topic=36313.msg1318217#msg1318217 should be corrected from "number offull-wave patterns along the longitudinal length " to "number of half-wave patterns along the longitudinal length "QuoteThe first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the cylindrical cavity. It is zero for modes in which there is no variation in the circumferential direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes).
The third subscript (p) is the longitudinal mode number. It indicates the number offull-wave patterns along the longitudinal length of the waveguide. It is zero for modes in which there is no variation in the longitudinal direction.
to:
The first subscript (m) is the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the cavity. It is zero for modes in which there is no variation in the circumferential direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes). The radial mode number (n) minus one indicates the number of middle nodes across the diameter (not counting as nodes the end nodes). The radial mode number (n) cannot be zero.
The third subscript (p) is the longitudinal mode number. It indicates the number of half-wave patterns along the longitudinal length of the cavity. It is zero for modes in which there is no variation in the longitudinal direction.
I double-checked the others (m and n) and I am sure that they are correct.
The US Navy reference is correct. GO NAVY !
(http://orangehoodie.com/photo/lifeliberty800.jpg)
Concerning, "m" "the azimuthal mode number: it indicates the number of full-wave patterns around the circumference of the cavity, all the descriptive references you brought up agree (as we previously discussed in this thread).
Concerning "n" (the radial mode number that "indicates the number of half-wave patterns across the diameter"), the Wikipedia link is incorrect -I didn't have the time to check the history of that Wiki entry to see what is the history of that Wikipedia error. When I have the time I will examine that and I will correct the entry in Wikipedia.
To make the long story short, the quantum mode numbers have to respect the boundary conditions:
1) In the circumferential direction there is really no boundary, the condition is one of periodicity, hence m must be the number of full waves in the circumferential direction. All references agree
2) In the radial and longitudinal directions, the boundary conditions (electrical conductivity at the surfaces) are at each end of the diametral direction or at each end of the longitudinal direction. There is no boundary condition at the center of the circular cross-section other than symmetry or antisymmetry (unless it would be a double-concentric cylinder having an inner conductive cylinder in addition to the outer conductive cylindrical surface) hence a half-wave can be supported within the diameter direction and a half-wave can be supported within the longitudinal direction. Hence the radial and longitudinal directions n and p are the number of half-waves in both directions, just like a rectangular cavity.
..
I figured out the confusion I had over the m subscript after studying the KWOK 3.01ghz coke can, and the 2.45ghz example. The issue is, wavelengths is NOT the same as wave pattern. For both the frequency examples, you get pretty much exactly 2 wavelengths around the circumference, which breaks TE111. So wavelengths is where I got it wrong. My old n subscript was jacked up too. As the Navy example states, and @Rodal did too. It is wave PATTERN. Glad I got that sorted out. So the Navy example is correct, and then add the p subscript from my old post, and it all falls in to place, as Rodal typed it out above the Navy logo, which is perfect.
So around a circumference there is of course no E field boundary condition, so trying to quantify it in wavelengths makes no sense. Pattern variation does. On the other hand, across a diameter or along the length, standard E field boundary conditions apply, so pattern or half wavelengths works equally well. I'm being super cautious before I sink cash on a large copper sheet, so I'm testing everything.
...I made the changes in the Wikipedia page https://en.wikipedia.org/wiki/Transverse_mode#Types_of_modes , to correct "wavelength" to "wave pattern" and the expressions for m and n for the circular waveguide. I also added the US NAVY reference. Let's see how long these corrections last in the Wikipedia world where anybody gets to be an Oracle :)
Concerning "n" (the radial mode number that "indicates the number of half-wave patterns across the diameter"), the Wikipedia link is incorrect -I didn't have the time to check the history of that Wiki entry to see what is the history of that Wikipedia error. When I have the time I will examine that and I will correct the entry in Wikipedia.
...
I've attached a video that Tom Ligon made for me some time ago. Can anyone tell me what mode this is, in particular, what is "p" . As for the operating frequency - it is consistent within meep and Harminv but these last few pages of discussion have shaken my confidence that it is consistent with the real world for those cavity dimensions.
The cavity is similar to the Brady cavity in perfect metal, but the dielectric constant is to high.
I don't expect to make a new video until I get the frequencies and modes sorted out.
The third subscript (p) is the longitudinal mode number. It indicates the number of half-wave patterns along the longitudinal length of the cavity. It is zero for modes in which there is no variation in the longitudinal direction.
The second subscript (n) is the radial mode number: it indicates the number of half-wave patterns across the diameter. The radial mode number (n) plus one indicates the number of nodes across the diameter (counting as nodes the end nodes). The radial mode number (n) minus one indicates the number of middle nodes across the diameter (not counting as nodes the end nodes). The radial mode number (n) cannot be zero.
I was wondering if this phenomena might have an effect on this system?
http://gizmodo.com/sub-atomic-particles-could-accelerate-themselves-1681765188 (http://gizmodo.com/sub-atomic-particles-could-accelerate-themselves-1681765188)
@Rodel
I believe that your answer is that the mode is
TX a,1,3
where X = (E or M)
it could be that a = 1, 2, ... or more.
There must be an upper limit on the value of a, but ...
...
.....
I am looking into ParaView, an open source data visualization tool. With it, I might be able to generate some 3D views of interest but movies are to hard. Making of that movie took 12 hours of CPU, another 8 hours to upload the PNG files to Box, and I don't know how long to download and make the movie, then send it back. To hard just for simple exploration of the data.
...'m still working that problem but have determined that it is either an issue with Harminv or with my use of Harminv. But it's not geometry or frequency input values, rather it is signal amplitude, run time and wait time issues. Most likely all of them. In the video I posted, it is clear that the cavity is resonating strongly at the drive frequency. The drive frequency is only moderately near the Brady experimental drive frequency. I took that to be a result of the relatively higher dielectric constant used, 2.3 compared to the 1.76 value that gives the Brady experimental value of 1.8804 GHz. ...
Cavity optomechanics studies the interaction between light and mechanical systems, most often mediated by radiation pressure—the force exerted by photons hitting on a mirror. In a typical optomechanics setup, microwave or optical photons travel in a cavity formed by two or more mirrors, one of which is free to move and acts like a mechanical oscillator whose position changes because of radiation pressure and thermal fluctuations. A recent milestone in the field was the cavity cooling of mechanical oscillators to a regime in which they have less than one quantum of motion [1]. This could have important applications, ranging from the observation of quantum behavior in macroscopic systems to the development of ultrasensitive detectors that could reveal the tiny vibrations caused by the still-elusive gravitational waves. However, to-date-demonstrated schemes require that the frequency of the cooling light be lower than the cavity resonant frequency by an amount corresponding to the frequency of the mechanical oscillator. These two frequencies can be measurably different only if the oscillator’s frequency is sufficiently large. This poses an important limitation, as low frequency, heavy oscillators cannot be cooled by this method.
Now a team led by Roman Schnabel at the Albert Einstein Institute in Hannover, Germany has reported an optomechanical cooling scheme that gets rid of this frequency-detuning requirement [2]. The key to their achievement is a novel form of optomechanical coupling. Optomechanics has been mainly investigated using “dispersive coupling,” in which displacements of the oscillating mirror change the resonant frequency of the cavity [3]. Here, the authors rely instead on “dissipative coupling,” in which the mirror oscillations modify the coupling between the cavity and its environment, for instance by modulating the speed at which cavity photons are lost (i.e., the cavity bandwidth).
In the dispersive coupling regime, the most widely used cooling approach is “cavity cooling” [3]. In this method, light cools a mechanical mode via a “parametric” process: quanta of mechanical excitations are up-converted into cavity photons, which are then dissipated through the cavity. The light frequency must be detuned from the cavity resonant frequency: the mechanical oscillator produces lower-frequency (red) and higher-frequency (blue) sidebands, which are shifted from the cavity resonance by multiples of the mechanical frequency ωM. When the driving frequency is tuned to the first red sideband, photons entering the cavity take away phonons with energy ħωM from the mechanical system, cooling the oscillator. In a number of previous studies, this method allowed researchers to bring mechanical oscillators to their quantum ground state (i.e., states in which the average number of mechanical excitations is reduced below unity) [1] and to realize the coherent conversion of photons to mechanical motion and of microwave photons to optical photons [4]. But these realizations required the system to be in the “resolved sideband regime”: for the red sideband to be distinguishable from the cavity frequency, the frequency of the mechanical oscillator (determining the shift of the sidebands) has to be larger than the cavity bandwidth. Ground-state cooling has been achieved for frequencies down to hundreds of megahertz, but reaching lower frequencies (such as the ∼100-kilohertz frequency of the mechanical resonator used by Schnabel’s team) would require cavities with extremely narrow bandwidths, which are currently not available.
However, a recent theory shows that cavity cooling could be possible without the requirement to resolve the mechanical-oscillator sidebands [5] if the optomechanical coupling is dissipative [6]. In dissipatively coupled systems, two types of fluctuating forces act on the mechanical resonator: the noise in the light injected into the cavity and the quantum fluctuation of the cavity field. These two types of noise, which have different spectra, can interfere destructively. With proper parameter choice, such interference can reduce the spectral density of the noise at the frequency (-ωM) of the oscillator, effectively cooling it. This mechanism, which does not require to resolve the sidebands, can work with a low oscillator frequency.
...For:
I have made progress though. Using the frequency formula to adjust cavity length so that the formula gave 2.45GHz, required a cavity length about 0.0965 meters. Iteratively running meep and adjusting the cavity length to force resonance at 2.45 GHZ independently produced a cavity length of 0.0936 meters.
I emphasize that I worked those problems independently of each other so the fact that they are in near agreement is telling. I would like to find a combination length and radius that would give the frequency without the length being so close to 3/4 wavelength. In fact, I would like for the length to be exactly one wavelength and for which I knew the mode. TE 1,1,1 would be good, but TE 1,4,1 might also work. Maybe now that I have found one solution, I can find more solutions.
I found this very interesting (expired) 1969 patent by Grant, owned by JOHNSON CONTROLS INTERNATIONAL, that deals with conical cavities !
http://www.google.com/patents/US3425006
It has a lot of interesting practical stuff, for example dealing with spherical ends (like in Greg Egan's solution http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html ) instead of flat end plates (NASA Brady et.al., Shawyer(Experimental and Demo) and Prof. Juan Yang in China's EM Drives all have flat ends):
It has been found possible to predict the resonances approximately by defining a phase shift per unit length as 21r/ \g, where Ag is given by the usual formula for circular wave-guides of diameter D, but where D and hence Ag vary along the cone. If this phase shift is integrated from the location of the cut-off diameter to the position of the plunger or movable end wall, resonances will be found when the integral has values of 11 pi."Looks like math for predicting resonant modes for cones. It looks like some of the text got messed up in the character translation over to Google patents, see the bold part.
I found this very interesting (expired) 1969 patent byGrantWolf, owned by JOHNSON CONTROLS INTERNATIONAL, that deals with conical cavities !
http://www.google.com/patents/US3425006
It has a lot of interesting practical stuff, for example dealing with spherical ends (like in Greg Egan's solution http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html ) instead of flat end plates (NASA Brady et.al., Shawyer(Experimental and Demo) and Prof. Juan Yang in China's EM Drives all have flat ends):
Found some time to read over this patent. It is a gold mine of good info. Great find. A couple takeaways I found is that it confirms that TE modes are highly desirable compared to TM. Also this caught my eye:QuoteIt has been found possible to predict the resonances approximately by defining a phase shift per unit length as 21r/ \g, where Ag is given by the usual formula for circular wave-guides of diameter D, but where D and hence Ag vary along the cone. If this phase shift is integrated from the location of the cut-off diameter to the position of the plunger or movable end wall, resonances will be found when the integral has values of 11 pi."Looks like math for predicting resonant modes for cones. It looks like some of the text got messed up in the character translation over to Google patents, see the bold part.
....
Found some time to read over this patent. It is a gold mine of good info. Great find. A couple takeaways I found is that it confirms that TE modes are highly desirable compared to TM. Also this caught my eye:QuoteIt has been found possible to predict the resonances approximately by defining a phase shift per unit length as 21r/ \g, where Ag is given by the usual formula for circular wave-guides of diameter D, but where D and hence Ag vary along the cone. If this phase shift is integrated from the location of the cut-off diameter to the position of the plunger or movable end wall, resonances will be found when the integral has values of 11 pi."Looks like math for predicting resonant modes for cones. It looks like some of the text got messed up in the character translation over to Google patents, see the bold part.
Glad you agree that this 1969 patent is a gold mine for people interested in EM Drives.
Please see the attached Adobe Acrobat .pdf file of page 3 of the original patent, top of column 4, for the actual formulas and symbols
The patent states
"n * Pi" instead of "11 * Pi"
"2 * Pi / Lambdag " instead of b]21r/ \g[/b]
"Lambdag" instead of "Ag " where Lambdag must mean the waveguide's wavelength
I'm puzzled as to why you are using an excitation frequency of 2.45 GHz which does not correspond to any natural frequency of the cavity. If you want to excite TE110 you should use an excitation frequency of 2.32677 GHz (using the speed of light in air, while if you use the speed of light in vacuum it would be 2.32745 GHz). The natural frequency of mode shape TE110, 2.33 GHz, is independent of the length of the cavity.
QuoteI'm puzzled as to why you are using an excitation frequency of 2.45 GHz which does not correspond to any natural frequency of the cavity. If you want to excite TE110 you should use an excitation frequency of 2.32677 GHz (using the speed of light in air, while if you use the speed of light in vacuum it would be 2.32745 GHz). The natural frequency of mode shape TE110, 2.33 GHz, is independent of the length of the cavity.
It's very simple. 2.45 GHz is a given.
Cavity length and radius are the independent variables to be adjusted to establish resonance at 2.45 GHz.
And yes, I'm quite sure I want TE 1,1,1 mode.
Isn't it possible to increase radius while leaving length at or around 12 cm? I would prefer that but can't find a radius that works with 2.45 GHz.
Well according the above posts and others, http://forum.nasaspaceflight.com/index.php?topic=36313.msg1320981#msg1320981 we're all getting pretty adept at using our skills/resources for calculating resonant modes of cylinders, which is a good first step. Well I'm learning new skills as I go along. So I can do cylinders all day, cones...not so much..yet. I certainly didn't come to the table knowing how to calculate resonant modes of anything 5-6 months ago.
I'm trying to figure out how to use the (2 * Pi ) / (Lambdag ) expression from the patent or the Volumetric Mean approach (which is better?) toward calculating resonant modes of conical frustums. I think the holy grail would be a quick and easy correction to convert from cylinder solutions to conical frustums.
So the (2 * Pi ) / (Lambdag ) above, does that mean what when I take 6.28 and divide that by x wavelength, and get a multiple of pi, that diameter or can support a resonant mode?
Trying to figure out how to convert this cylinder to a cone, by keeping the diameter as the small diameter, adjusting the length to arrive at the new large diameter along a 45 or 90 degree cone, and still maintain resonance @ 2.45ghz TE111:
2.45ghz, TE111
L=0.1224489m
D=0.08278945m
..
So the (2 * Pi ) / (Lambdag) above, does that mean what when I take 6.28 and divide that by x wavelength, and get a multiple of pi, that diameter or can support a resonant mode?
...
Isn't it possible to increase radius while leaving length at or around 12 cm? I would prefer that but can't find a radius that works...That's another reason why to compare a numerical solution (by Finite Difference, Finite Element or any other numerical method that relies on a mesh to obtain results) to an exact solution, you should first pick dimensions, discretize the problem to a fine mesh to ensure convergence (this is what takes most of the person's time in a numerical solution) and if necessary, explore different exciting frequencies (keeping dimensions constant, instead of keeping the same excitation frequency and changing dimensions, which means changing the mesh). For example using the exciting frequency of 2.63GHz for TE111 (for MeepDiameter = 7.54898 centimeter, MeepLength = 12.2364 centimeter) as obtained by @Mulletron and me.
...Ok, I did run it again with bandwidth = 0.2 * Drive frequency, for cases up to resolution of 80, but I didn't get anything. Once I narrow the bandwidth to exclude the resonant frequency at 1.87 GHz, there are no resonances within the bandwidth.
What did you use for the bandwidth source around the frequency of interest (Drive frequency 2.45 E+9 Hz)?
Could you try running all these cases again, everything the same as before except with a significantly narrower bandwidth source around the frequency of interest ? . Reportedly harminv does a better job the narrower the source is around the frequency of interest .
Harminv does work better at identifying the resonant frequency with narrower bandwidth, when the frequency is within the bandwidth. I set the drive frequency to 1.873 GHz, narrowed the bandwidth to 0.07 * frequency and got this:
frequency Quality factor error
1,873,339,229.3075 Hz 18,325,307.0778158 1.673972608680621e-7+0.0i
....
Meanwhile, I would particularly appreciate @NotSoSureOfIt 's comments regarding Wolf's suggestion on how to calculate the resonances of a truncated cone cavity (lines 60 to 75 of column 3 and lines 1 to 11 of column 4) of the US patent #3,425,006 (which I attach below as an Adobe Acrobat .pdf document).
Publication number US3425006 A
Publication date Jan 28, 1969
Filing date Feb 1, 1967
Priority date Feb 1, 1967
Inventors Wolf James M
Original Assignee Johnson Service Co
Yes, thank you for looking at it, and formulating the eigenvalue problem :).
Meanwhile, I would particularly appreciate @NotSoSureOfIt 's comments regarding Wolf's suggestion on how to calculate the resonances of a truncated cone cavity (lines 60 to 75 of column 3 and lines 1 to 11 of column 4) of the US patent #3,425,006 (which I attach below as an Adobe Acrobat .pdf document).
Publication number US3425006 A
Publication date Jan 28, 1969
Filing date Feb 1, 1967
Priority date Feb 1, 1967
Inventors Wolf James M
Original Assignee Johnson Service Co
Mmmm.. That's the argument that I used to come up w/ "volumetric". Been otherwise occupied, but I'll take a look at it as time permits.
Edit: Lessee, that's the "guide" wavelength, for equal phase planes.
Basically, you want to solve for the k[sub z] w/ R as a function of z.
like k[sub z]^2 = (omega/c)^2- (X[sub m,n]/R[fn z])^2 or X'
We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.
Isn't it possible to increase radius while leaving length at or around 12 cm? I would prefer that but can't find a radius that works with 2.45 GHz.
Yes, it's possible.
If you insist in specifying the exciting frequency as 2.45GHz and the length (12 cm) of the cylindrical cavity, and having the diameter as the variable to be adjusted, then
....
= 8.332965999678832` centimeters
instead of the diameter=7.54898 centimeter you used.
@Aero, is the reason why you insist in keeping a frequency of 2.45GHz in your modeling because you are looking at making a small EM Drive using a kitchen's microwave's magnetron as the source (which are nominally ~ 2.45 GHz) ?
....I think one has a greater chance of achieving thrust (it that is indeed possible) with mode shape TE01p than with mode TE11p, for any p. The images below illustrate the difference between them.
I in particular am trying fervently to find a solution for an unloaded conical frustum geometry resonant at 2437mhz at TE111 to start with. 2450mhz is a good start. From there you can perturb the cavity down to 2437mhz at will (mostly trial and error)...
...I am still unsure if angle by the apex is truly important for resonance, but according to Egan, it is: http://www.gregegan.net/SCIENCE/Cavity/Cavity.html But if my hunch about the importance of the QV to spacetime is correct (pretty much has to be), 45 and 90 degrees by the apex is important. ..
I learned a new trick. :) Here are some images of the ez field along the x coordinate.
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
I learned a new trick. :) Here are some images of the ez field along the x coordinate.Are you running the same dielectric properties, overall geometry and source frequency as in your message http://forum.nasaspaceflight.com/index.php?topic=36313.msg1321460#msg1321460 ?
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
I will try to get additional views as time and health permits. My boy brought something home from school and we've all contracted it. Unfortunately for me, I didn't throw it off like the wife and boy did.Thanks for updating us on your great progress. Hope you feel better soon :)
This image is in 3D, which means very low resolution, so no its not like the other one. It's the same cavity and same drive frequency though so it should be generally very similar.
I learned a new trick. :) Here are some images of the ez field along the x coordinate.
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
I used the dielectric constant of 1.76 for the dielectric disk. That number was 2.3 in the movie but I only use 1.76 now that I've decided that 1.76 is the correct value. To investigate resonance of an empty cavity I can replace the dielectric material with "air." The value is 1.76 for the above runs.I learned a new trick. :) Here are some images of the ez field along the x coordinate.
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
For these truncated cone calculations, you reported (in the movie attachment to http://forum.nasaspaceflight.com/index.php?topic=36313.msg1321460#msg1321460 ) that the value of the relative permittivity (dielectric constant) you used was 2.3.
I did not find the value of relative permeability ( the degree of magnetization of the material ) you used for your truncated cone (NASA Brady et.al.) calculations.
Just to be sure, could you please confirm that you used a value of 1 (one) for the relative permeability in the above calculations ?
I used the dielectric constant of 1.76 for the dielectric disk. That number was 2.3 in the movie but I only use 1.76 now that I've decided that 1.76 is the correct value. To investigate resonance of an empty cavity I can replace the dielectric material with "air." The value is 1.76 for the above runs.I learned a new trick. :) Here are some images of the ez field along the x coordinate.
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
For these truncated cone calculations, you reported (in the movie attachment to http://forum.nasaspaceflight.com/index.php?topic=36313.msg1321460#msg1321460 ) that the value of the relative permittivity (dielectric constant) you used was 2.3.
I did not find the value of relative permeability ( the degree of magnetization of the material ) you used for your truncated cone (NASA Brady et.al.) calculations.
Just to be sure, could you please confirm that you used a value of 1 (one) for the relative permeability in the above calculations ?
..
..." I do move the antenna location around and often forget to put it back to the most representative location for the run type. I move it because when I run Harminv using Cylindrical coordinates, the antenna must be on the central axis of rotation of the cone. If it is not, then in Cylindrical coordinates, nothing excites the cavity.I learned a new trick. :) Here are some images of the ez field along the x coordinate.
The imaginary and real parts are shown at x=194, because that showed a powerful signal.
The imaginary and real parts are shown at x=216, because that is the big end of the cavity.
The imaginary and real parts are shown at x=39, because that is the just inside the dielectric at the small end.
I'll see if I can get some magnetic field images.
For these truncated cone calculations, you reported (in the movie attachment to http://forum.nasaspaceflight.com/index.php?topic=36313.msg1321460#msg1321460 ) that the value of the relative permittivity (dielectric constant) you used was 2.3.
I did not find the value of relative permeability ( the degree of magnetization of the material ) you used for your truncated cone (NASA Brady et.al.) calculations.
Just to be sure, could you please confirm that you used a value of 1 (one) for the relative permeability in the above calculations ?
...I am still unsure if angle by the apex is truly important for resonance, but according to Egan, it is: http://www.gregegan.net/SCIENCE/Cavity/Cavity.html But if my hunch about the importance of the QV to spacetime is correct (pretty much has to be), 45 and 90 degrees by the apex is important. ..
@Mulletron, why do you think that the cone angle (thetaw in Egan's nomenclature), of an EM Drive, should (ideally) be 45 degrees ? (I don't recall the reasons(s), please refresh my mind).
"Currently have two ways to find the electromagnetic field of the rectangular and circular waveguides, the eigen-value equation which is an analytical method and numerical solution, when finding solution for the resonator, Maxwell equation in is need to be created in a spherical coordinate system, because the complexity of the spherical coordinate fielder equation, has not found anyone using eigen-value method to calculated the distribution of the resonant field. Only find in Paper [4] using asymptotic method for conical waveguide. That method assume a equivalent radius ae, believes field of wavefront sphere of cone waveguide Eo,EФ,Ho,HФ can use its wavefront position radius ae equivalent circular waveguide field Er,EФ,Hr,HФ, this method of finding the field distribution within the conical resonator can be used as reference, but the accuracy reduced as the cone half opening angle increases. Using finite element to numerically simulate the Maxwell electromagnetic equation for the idealised conical resonator, the distribution of electromagnetic can be obtained directly, this method is not limited by the cavity structure and microwave mode."
By keep the diameter of the Small End constant, increase the large end of the cavity, in order to have the same resonant frequency, cavity height must be reduced, quality factor also reduce.
(*
"Shawyer EXPERIMENTAL geometry"
shawyerExpLength=0.156 meter;
shawyerExpBigDiameter=0.16 meter
shawyerExpSmallDiameter=0.127546 meter;
*)
(*
" Shawyer DEMO geometry"
shawyerDemoLength=0.345 meter;
shawyerDemoBigDiameter=0.28 meter;
shawyerDemoSmallDiameter=0.128853 meter;
*)
(*
"Shawyer EXPERIMENTAL geometry"
shawyerExpLength=0.156 meter;
shawyerExpBigDiameter=0.16 meter
shawyerExpSmallDiameter=0.127546 meter;
*)
(*
" Shawyer DEMO geometry"
shawyerDemoLength=0.345 meter;
shawyerDemoBigDiameter=0.28 meter;
shawyerDemoSmallDiameter=0.128853 meter;
*)
These were both 2450mhz experiments. Where did the small diameters and lengths come from? I see the Large diameters here: http://www.emdrive.com/yang-juan-paper-2012.pdf.
Suppose that there was a box with hypothetical 100% reflecting internal walls. It would be possible to trap some light energy in such a box. A freely propagating photon is a massless particle, but what about a “confined photon” trapped in the box. That photon is forced to have the box’s specific frame of reference. A calculation at the end of chapter 1 shows that the photon pressure exerted on the walls of the box is uniform if the box is not accelerating, but the pressure becomes unequal if the box is accelerated. This difference in pressure results in a net force which resists acceleration. This is the inertia of the confined photon energy and it exactly equals the inertia of an equal amount of energy in the form of matter particles. This is not a coincidence.That scenario sure sounds familiar......like within magic resonant cavity thrusters. I read that a few days ago and really didn't believe any of it, but I filed it away for later.
.......the photon pressure exerted on the walls of the box is uniform if the box is not accelerating, but the pressure becomes unequal if the box is accelerated. This difference in pressure results in a net force which resists acceleration.
A photon trapped in such a cavity behaves as if it had mass; in other words, the cavity creates a "trapping potential," keeping the photons from escaping.http://www.desy.de/user/projects/Physics/Relativity/SR/light_mass.html
However, if light is trapped in a box with perfect mirrors so the photons are continually reflected back and forth in both directions symmetrically in the box, then the total momentum is zero in the box's frame of reference but the energy is not. Therefore the light adds a small contribution to the mass of the box.But then what? Can one really say with confidence that there exists a condition of "mass flow?"
....
Keeping first principles in mind concerning the QV model for how these thrusters may work. If they do interact with the QV somehow, their design should obviously be complimentary to the geometry of spacetime (there are crazy folks out there http://www.onlyspacetime.com/, I'm one of them, who believe spacetime emerges from the quantum world.) I wanted to test whether opening angle had any significance. When faced with choosing an opening angle amongst seemingly arbitrary angles I've found amongst Shawyer's prototypes, I wondered if a light cone opening angle of 45 degrees (measured from the longitudinal axis for a total of 90 as measured from outside) would be of any benefit or not. http://en.wikipedia.org/wiki/Minkowski_diagram After seeing that a light cone setup would be a ginormous cone after factoring in the necessary conical sections for front and end walls, I further halved it to 22.5 degrees (total of 45). That's why I have 2 drawn up in CAD. So it really came down to a question of what angle to pick out of so many choices. Those two I want to try.
Trying to reconcile the above ideas with simultaneously hunting a viable rf solution is proving daunting. Mostly due to the lack of resources. I may not be afforded the option to choose an opening angle and stay on freq and within reasonable size limits. As I'm researching this it is becoming clear that opening angle will be dominated by chosen frequency and practical considerations.
After following up on Aero's post: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1274400#msg1274400 about this: http://www.emdrive.com/NWPU2010translation.pdf trying to see if I can find a good solution for calculating exact solutions for conical frustums, I learned that no such method exists to find closed form solutions to that problem. The Egan method is similar to what we need but it doesn't address the problem. None of what we're dealing here has spherical end caps. And honestly, the Egan way is way too high speed for me.Quote"Currently have two ways to find the electromagnetic field of the rectangular and circular waveguides, the eigen-value equation which is an analytical method and numerical solution, when finding solution for the resonator, Maxwell equation in is need to be created in a spherical coordinate system, because the complexity of the spherical coordinate fielder equation, has not found anyone using eigen-value method to calculated the distribution of the resonant field. Only find in Paper [4] using asymptotic method for conical waveguide. That method assume a equivalent radius ae, believes field of wavefront sphere of cone waveguide Eo,EФ,Ho,HФ can use its wavefront position radius ae equivalent circular waveguide field Er,EФ,Hr,HФ, this method of finding the field distribution within the conical resonator can be used as reference, but the accuracy reduced as the cone half opening angle increases. Using finite element to numerically simulate the Maxwell electromagnetic equation for the idealised conical resonator, the distribution of electromagnetic can be obtained directly, this method is not limited by the cavity structure and microwave mode."QuoteBy keep the diameter of the Small End constant, increase the large end of the cavity, in order to have the same resonant frequency, cavity height must be reduced, quality factor also reduce.
They're basically saying: (1) That I'm hosed trying to calculate such things. Simulating the conical frustum using FEM software is the way to go. Which I simply don't have access to. (2) Also they're saying that as the opening angle opens up, approximating the resonant modes becomes more and more difficult. (3) You have to shorten the cavity height as opening angle increases to maintain resonance at desired frequency, but it lowers Q. So I should probably (for now) re-think using such wide opening angles.
So I'm switching gears a bit using what I've learned from the above reporting.
(1) Keeping Cannae in mind, who says we need a cone anyway? We've discussed the commonality between Shawyer and Cannae in thread 1. http://forum.nasaspaceflight.com/index.php?topic=29276.msg1298712#msg1298712 So I'm thinking it would be smart to use what we've learned about cylinders and try a cylinder experiment.
(2) Instead of trying to optimize right out of the gate by throwing around light cones. It would be smarter to use the dims we already have for Shawyer experimental and demo, which you provided on the previous page.
(3) If I ever get this build going, I'm going to have to easter egg it anyway using a sig-gen and a power meter to find the resonant frequency (treat it like a filter, tune it until I get get an output from sample port), so I don't need to have exact calculations. I just need to be close enough to be within tunable limits.
As for the previous one, the level and quality of these comments is so high that the thread has become unreadable for non-physicists.
Could you eventually, for the sake of not losing the majority of us too much behind, make a quick non-technical summary of what are you discussing? is there any progress or barely nothing?
Thanks! :)
A potentially interesting sidelight:
http://okomov.livejournal.com/577.html
The physics is descrived in vvery different terms ("Leonov’s superunification theory"?? "Antigravity"???) this has similar performance to what Shawyer predicts for a superconducting EmDrive thruster, i.e. 500 to 700 kg for 1kW power input.
Moreover, as soon as it starts to accelerate, the thrust ceases, hence the pulsed operation in the video, which is what Shawyer claims for a high Q EmDrive thruster without Doppler compensation.
What does the team think...?
For people more familiar with NASA, is that common? Does NASA as a civilian agency have a history (or policy?) of suppressing experimental results that, like this, may have military applications? In other words, can the lack of any news at all one way or the other, be taken as a sign that there might be something to this? Or is that just conspiratorial nonsense?
For people more familiar with NASA, is that common? Does NASA as a civilian agency have a history (or policy?) of suppressing experimental results that, like this, may have military applications? In other words, can the lack of any news at all one way or the other, be taken as a sign that there might be something to this? Or is that just conspiratorial nonsense?
Rockets have military applications, but NASA does not suppress experimental results of rockets. To the contrary, they partner with companies such as SpaceX and share information for the advancement of space exploration. I'm not convinced there is a black out for EM drive technology. There appears to be a delay, which could have many causes. If there are people in the administration advocating for a black out, I think it is a mistake, and probably too late given the amount of information already in the public domain.
Anyone have the pdf?
http://arc.aiaa.org/doi/abs/10.2514/6.2014-3853
Also not exactly mainstream news but interesting nonetheless.
http://m.disclose.tv/news/NASA_Impossible_Quantum_Space_Engine_Actually_Works/113761#DTV
Anyone have the pdf?
http://arc.aiaa.org/doi/abs/10.2514/6.2014-3853
For people more familiar with NASA, is that common? Does NASA as a civilian agency have a history (or policy?) of suppressing experimental results that, like this, may have military applications? In other words, can the lack of any news at all one way or the other, be taken as a sign that there might be something to this? Or is that just conspiratorial nonsense?
Rockets have military applications, but NASA does not suppress experimental results of rockets. To the contrary, they partner with companies such as SpaceX and share information for the advancement of space exploration. I'm not convinced there is a black out for EM drive technology. There appears to be a delay, which could have many causes. If there are people in the administration advocating for a black out, I think it is a mistake, and probably too late given the amount of information already in the public domain.
To be fair to NASA if this does work it's such a revolutionary technology that the reporting of it is not something to be rushed into. No doubt every result is having to be checked, checked again & then checked again etc etc which no doubt slows down the release of information. Especially if on top of that there are national security implications that have to be considered as well.
Wanted to examine the inventor's theory of operation. We spent a lot of time discussing Shawyer's theory, but Fetta didn't get much discussion. Probably because his paper is paywalled. Also @Wembley, thanks for the patents. There's plenty of free info there.
Break:
Neat I can hit zero every half wavelength with any frequency like this. (top)
Or if I mirror the diagonal of a cylinder, creating a cone I get pretty close sometimes after adjusted down 1 degree. (bottom)
http://goo.gl/jF8ZJB (shortened link to ebay)
Found these puppies. Emailed the seller to see what the dimensions are and to see if they are the manufacturer and whether they do custom sizes. Might be cheaper and less headache than buying a copper sheet.
It is all falling into place very nicely now :)
http://goo.gl/jF8ZJB (shortened link to ebay)
Found these puppies. Emailed the seller to see what the dimensions are and to see if they are the manufacturer and whether they do custom sizes. Might be cheaper and less headache than buying a copper sheet.
"apx. dimensions small= 6 5/8" x 3 3/8" medium= 8" x 5" large=11" x 7 3/4" all are 7 3/4" tall . yes we do make them @ our sheet metal shop & sure we can make custom sizes. Thanks Rick"
..Thanks Paul for an excellent update, much appreciated.
Folks:
The Eagleworks Lab is still working on the copper frustum thruster that was reported on last summer at the AIAA/JPC. We have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum. However we continue to fight through RF amplifier failures brought on by having to operate them in a hard vacuum with few $$$ resources to fix them when they break, so the desired data is coming along very slowly. We are still working on obtaining enough data though that will allow us to go to Glenn Research Center (GRC) for a replication effort in the next few months. However that will only happen if we can make the thrust signature large enough since the GRC thrust stand can only measure down to ~50uN, so we have to get the thrust signature up to at least 100uN before we can go to GRC.
As to the theoretical side of Q-Thrusters, Dr. White has just developed the first cut at a quantum vacuum (QV) based plasma code written in C+ under Windows/Unix and VMD visualization software that utilizes the COMSOL E&M derived field data for a given thruster geometry that allows one to track the movement and velocity of a subset of the QV's electron/positron neutral plasma pairs in the thruster over time as they respond to the applied time varying RF E&M fields in the copper frustum resonant cavity and to each other. This package also allows one to calculate the expected thrust for a given input power and quality factor of the frustum resonant cavity based of standard plasma rocket physics. So far the estimated thrust verses experimental observations are within 2% for the first experimental data run I compared it to, but we still have a long, long road ahead of us of experimental validation before we have any real confidence in this very new Q-Thruster design tool.
Best, Paul March
It is all falling into place very nicely now :)
...
In theory, could a dialectric be used to suppress resonance modes that might otherwise be present in an over-sized cavity?
Here's what I know about cutoff freqs of circular waveguide at least:The US Navy reference should be corrected to read instead:
"The cutoff wavelength of a circular guide is 1.71 times the diameter of the
waveguide. ...
Got the sample pack in the mail today. Will report on performance of 10 or 16 mil soon, specifically the ability to hold shape under its own weight while being as light as possible. Now, since I found the supplier, who uses heavier 22 Mil/16 Ounce Copper (see above), these will probably end up as end caps. I don't know what I'm going to do yet, buy or roll'n'solder myself. There's tradeoffs to consider. Like time and weight. So shiny :)
Edit:
It just occurred to me that I should have enough material in hand right now to make something happen if I can find a solution to a cone based off this cylinder: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1320981#msg1320981
What do you think @Rodal? Do we have enough to confidently calculate a frustum of a cone that works and will fit within a 12"x12" sheet? The cylinder fits at least. I'm quite happy staying with 2.45ghz, TE111 for now. I don't care about finding the best mode for max thrust, just any thrust.
Not using a magnetron. I have test equipment. I can find the resonant frequency if we can calculate geometry close enough. The question is, in your opinion, is the math there to make an exact calculation yet?Definitely yes. :)
Break:
@ Paul March, thank you for chiming in. All of us are chomping at the bit for ANY news whatsoever. Maybe Eagleworks could leverage its social media presence (https://www.facebook.com/eagleworksnasa) to keep the public engaged. As far as the lack of $$$ and resources go, I understand that Eagleworks works on a shoestring budget. Wish we could help. It probably isn't acceptable for us to try and crowdfund a government agency. Hopefully you achieve results that will turn heads. Godspeed.
For people more familiar with NASA, is that common? Does NASA as a civilian agency have a history (or policy?) of suppressing experimental results that, like this, may have military applications? In other words, can the lack of any news at all one way or the other, be taken as a sign that there might be something to this? Or is that just conspiratorial nonsense?
Rockets have military applications, but NASA does not suppress experimental results of rockets. To the contrary, they partner with companies such as SpaceX and share information for the advancement of space exploration. I'm not convinced there is a black out for EM drive technology. There appears to be a delay, which could have many causes. If there are people in the administration advocating for a black out, I think it is a mistake, and probably too late given the amount of information already in the public domain.
To be fair to NASA if this does work it's such a revolutionary technology that the reporting of it is not something to be rushed into. No doubt every result is having to be checked, checked again & then checked again etc etc which no doubt slows down the release of information. Especially if on top of that there are national security implications that have to be considered as well.
Folks:
The Eagleworks Lab is still working on the copper frustum thruster that was reported on last summer at the AIAA/JPC. We have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum. However we continue to fight through RF amplifier failures brought on by having to operate them in a hard vacuum with few $$$ resources to fix them when they break, so the desired data is coming along very slowly. We are still working on obtaining enough data though that will allow us to go to Glenn Research Center (GRC) for a replication effort in the next few months. However that will only happen if we can make the thrust signature large enough since the GRC thrust stand can only measure down to ~50uN, so we have to get the thrust signature up to at least 100uN before we can go to GRC.
As to the theoretical side of Q-Thrusters, Dr. White has just developed the first cut at a quantum vacuum (QV) based plasma code written in C+ under Windows/Unix and VMD visualization software that utilizes the COMSOL E&M derived field data for a given thruster geometry that allows one to track the movement and velocity of a subset of the QV's electron/positron neutral plasma pairs in the thruster over time as they respond to the applied time varying RF E&M fields in the copper frustum resonant cavity and to each other. This package also allows one to calculate the expected thrust for a given input power and quality factor of the frustum resonant cavity based of standard plasma rocket physics. So far the estimated thrust verses experimental observations are within 2% for the first experimental data run I compared it to, but we still have a long, long road ahead of us of experimental validation before we have any real confidence in this very new Q-Thruster design tool.
Best, Paul March
I don't think funding discussions necessarily belong in this thread. Theory, potential application, and research results are one thing - figuring out how to pay for research on something that is not yet proven to create thrust (via the process of peer review and outside verification) is drifting dangerously close to territory that will earn a surefire thread closure.
..Thanks Paul for an excellent update, much appreciated.
Folks:
The Eagleworks Lab is still working on the copper frustum thruster that was reported on last summer at the AIAA/JPC. We have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum. However we continue to fight through RF amplifier failures brought on by having to operate them in a hard vacuum with few $$$ resources to fix them when they break, so the desired data is coming along very slowly. We are still working on obtaining enough data though that will allow us to go to Glenn Research Center (GRC) for a replication effort in the next few months. However that will only happen if we can make the thrust signature large enough since the GRC thrust stand can only measure down to ~50uN, so we have to get the thrust signature up to at least 100uN before we can go to GRC.
As to the theoretical side of Q-Thrusters, Dr. White has just developed the first cut at a quantum vacuum (QV) based plasma code written in C+ under Windows/Unix and VMD visualization software that utilizes the COMSOL E&M derived field data for a given thruster geometry that allows one to track the movement and velocity of a subset of the QV's electron/positron neutral plasma pairs in the thruster over time as they respond to the applied time varying RF E&M fields in the copper frustum resonant cavity and to each other. This package also allows one to calculate the expected thrust for a given input power and quality factor of the frustum resonant cavity based of standard plasma rocket physics. So far the estimated thrust verses experimental observations are within 2% for the first experimental data run I compared it to, but we still have a long, long road ahead of us of experimental validation before we have any real confidence in this very new Q-Thruster design tool.
Best, Paul March
Congratulations to the Eagleworks team for obtaining experimental force measurements in the torsional pendulum in a hard vacuum (~5.0x10^-6 Torr) !
(http://i262.photobucket.com/albums/ii105/scoozna/misc/applause.gif)
It would be most helpful to the scientific/technical community if you could provide the dimensions of the frustum of a cone (truncated cone) used in the Brady et.al. "Anomalous ..." report.
Of several estimates of the geometry, we have established that this is the best estimate so far:
Aero Best estimate as of 11/9/2014 http://forum.nasaspaceflight.com/index.php?topic=29276.msg1285896#msg1285896
cavityLength = 0.24173 m
bigDiameter = 0.27246 m
smallDiameter = 0.15875 m
where "cavity length" is the axial length of the frustum measured along the longitudinal axis of the cone, perpendicular to both the small and big diameters. In other words, the dimension labeled "h" in the following image: (http://offshoremechanics.asmedigitalcollection.asme.org/data/Journals/JMOEEX/28400/031603_1_1.jpeg)
It would be most helpful if you could provide the actual (internal) dimensions of the frustum (or at least if you could provide its approximate dimensions).
Thanks :)
...
The copper frustum we built and now are using has the following internal copper surface dimensions.
Large OD: 11.00" (0.2794m), Small OD: 6.25" (0.1588m) & Length: 9.00" (0.2286m) also see the attached slide with notes on the copper frustum's internal construction. I've also attached a slide with the TM212 E&M resonant mode we are currently exploring in this copper frustum cavity with a screen shot of the end on VMD display that shows the 100,000th simulation increment for this resonant mode. Each step in this plasma code is 1/72 of a full RF cycle, i.e., every 5.0 degrees of phase shift so each time step at 1,937.115 MHz is ~7.12 pico-seconds (10^-12s). Next is a picture of the forward thrust signature from this copper frustum taken in a ~5.0x10^-6 Torr vacuum. However we are currently trying to investigate the thermal response of the is copper frustum on the baseline of the torque pendulum after learning that I made a poor choice in how I built and mounted the copper frustum since it makes these thermal effects more pronounced in these thrust plots than they had to be. I'm appending a partial COMSOL thermal analysis of the copper frustum and I would like to get someone better versed in the art of thermodynamics than I to see if they calculate the expected thermal expansion of the copper frustum AND the polyethylene discs over a 60 second data run with ~50W of 1,937.115 MHz RF applied inside the cavity via a 14mm OD magnetic loop antenna made from 20 gauge magnet wire.
BTW, we have found that both the TE and TM E&M modes of this copper frustum can produce a thrust signature, but so far the TM modes appear to be the better performer, at least for the few modes we have been able to study to date. (Shawyer and the Chinese used the magnetron excited TE012 mode in their frustum cavities without dielectrics being present.)
Lastly, like any busy lab, Eagleworks could always use extra funding to deal with its daily heart burns and required salaries to keep it going. However we are currently a NASA sponsored facility, which sadly precludes being able to accept crowd sourcing or any other outside source of funding, unless it's through a commercial NASA Space Act Agreement that has to be approved up through NASA headquarters in Washington DC. In the meantime we limp along with the meager funding we are allotted until we either run out of time, or we finally prove our QVF/MHD conjecture is close enough to the reality so that we can start building Q-Thrusters with large enough thrusts, (tens to thousands of Newton), to be used on manned spaceflight missions.
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
Has anyone notified Dr. M re. precise cavity dimensions and latest forces from Paul? I would but don't have his link handy.I sent Dr. McCulloch a message as soon as I saw the dimensions. Thanks
Well here's an open one...... http://scharstein.eng.ua.edu/electromagnetic.pdf
(1) We have developed an exact analytical approach for the description of the electromagnetic
fields inside a hollow metallic waveguide with a taper. Analytical expressions for the spatital
distributions of electromagnetic field components, attenuation constant, phase constant and
wave impedance are derived.
(2)According to our theory the modes configurations inside a tapered hollow metallic
waveguide are similar to those in a cylindrical hollow metallic waveguide, but the
transmission characteristics and engergy densities distributions along propagating direction
have a different behavior. It is shown that all modes run continuously from a propagating
through a transition to an evanescent region and the value of the attenuation increases as the
distance from the cone vertex and the cone angle desrease. A strict distinction between pure
propagating and pure evanescent modes can not be achieved. There is no well-defined cutoff
wavelength but rather a cutoff radius. It is interesting to note that the magnitude of the cutoff
radius is related to the wavelength and the cone half-angle. The values of attenuation and
phase constants for the spherical TE and TM modes inside the tapered hollow metallic
waveguide depend on the cone half-angle very seriously. As the cone half-angle decreases, the
value of the attenuation increases. The smaller the cone half-angle is, the faster the modes
attenuate. This can explain why large taper angle may improve the light throughout in
aperture probe which finds an important application in scanning near-field optical microscopy
(3) As follows from our calculations, we find that in the propagating region the attentuation of
some modes decays faster than those of others, and one mode after the other reaches cutoff in
the tapered hollow metallic waveguide as the distance from the cone vertex decreases.
4) In the tapered hollow metallic waveguide, light is well confined in the hollow core (air
region) because it is reflected back to the core by a metal wall.
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
First off congratulations, and thank you very much for the information.
One question though. The use of a dummy load to the best of my understanding provides evidence to support that the thrust measurement device is not generating false positive data. Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
First off congratulations, and thank you very much for the information.
One question though. The use of a dummy load to the best of my understanding provides evidence to support that the thrust measurement device is not generating false positive data. Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?
Birchoff:
"Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?"
Yes and yes. In fact it was one of the requests made by the blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer. Even if will take a new mounting arrangement to get it accomplished.
Overall though the blue ribbon panel's experimentalists appeared to be pleased with our previous and upcoming lab work. However they ripped into Sonny's QVF/MHD conjecture because it relies on the quantum vacuum being mutable and engineer-able whereas the current physics mainstream thinks that the quantum vacuum is an immutable ground energy state of the universe that can-NOT be used to convey energy or momentum as proposed by Dr. White. However they brushed aside Sonny's QVF based derivation of the Bohr hydrogen atom electron radius as a "mathematical coincidence" and didn't have a word to say what the Casimir effect and other quantum vacuum phenomenon were caused by, that can only occur only if the QV is mutable and can convey energy and momentum. So Sonny and Jerry Vera took it upon themselves last fall to increase this mathematical coincidence from one to more than 47 times as they explored the QV created atomic electron shell radii for atoms up to atomic number 7 all based on the QV being the root cause for all of it including the origins of the electron and all other subatomic particles.
BTW, IMO Jim Woodward's Mach-Effect (M-E) conjecture that is based primarily on SRT and GRT, is still in the running for a way to explain his and our test results to date. However the M-E also has its detractors since it requires that instantaneous Wheeler/Feynman radiation reaction forces being required between a local time varying mass and all the other mass/energy in the casually connected universe, since this mechanism is used to balance the M-E's energy & momentum conservation books. In the end analysis though I think that the ME will rest on the quantum nature of space-time, since in Woodward's eyes the gravitational field IS space-time, and in our eyes GRT's space-time is in reality the quantum vacuum that probably has at least 4 spatial dimensions and one time dimension!
Best, Paul March
Thank you for the very interesting information about the "blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer." This is very relevant information to EM Drive Developments.
Paul, in your absence, the prior thread on EM Drives was derailed by polemical discussion of Woodward's Mach-Effect (M-E) conjecture (more info here: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1301657#msg1301657 ).
To avoid such issues, it may be preferable to continue discussion of that conjecture (Woodward's Mach-Effect) can be pursued at this thread, dedicated exclusively to Woodward's Mach-Effect: http://forum.nasaspaceflight.com/index.php?topic=31037.460 )
Thank you for the very interesting information about the "blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer." This is very relevant information to EM Drive Developments.
Paul, in your absence, the prior thread on EM Drives was derailed by polemical discussion of Woodward's Mach-Effect (M-E) conjecture (more info here: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1301657#msg1301657 ).
To avoid such issues, it may be preferable to continue discussion of that conjecture (Woodward's Mach-Effect) can be pursued at this thread, dedicated exclusively to Woodward's Mach-Effect: http://forum.nasaspaceflight.com/index.php?topic=31037.460 )
Sorry, I didn't know that Jim Woodward's work had become a hot potato, so I'll go to the M-E thread if the M-E topic comes up again.
Best, PM
Indeed we are all very delighted to hear from you Paul. This thread, and thread 1 has been a fury of activity trying to explore this proposition that we can possibly achieve all electric thrust in the vacuum of space without carrying propellant, and what it all means for science and humanity's future.
Given the reported results in vacuum, this is progress.
Patiently looking forward to reading "AnomalousThrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum"
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
First off congratulations, and thank you very much for the information.
One question though. The use of a dummy load to the best of my understanding provides evidence to support that the thrust measurement device is not generating false positive data. Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?
Birchoff:
"Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?"
Yes and yes. In fact it was one of the requests made by the blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer. Even if will take a new mounting arrangement to get it accomplished.
Overall though the blue ribbon panel's experimentalists appeared to be pleased with our previous and upcoming lab work. However they ripped into Sonny's QVF/MHD conjecture because it relies on the quantum vacuum being mutable and engineer-able whereas the current physics mainstream thinks that the quantum vacuum is an immutable ground energy state of the universe that can-NOT be used to convey energy or momentum as proposed by Dr. White. However they brushed aside Sonny's QVF based derivation of the Bohr hydrogen atom electron radius as a "mathematical coincidence" and didn't have a word to say what the Casimir effect and other quantum vacuum phenomenon were caused by, that can only occur only if the QV is mutable and can convey energy and momentum. So Sonny and Jerry Vera took it upon themselves last fall to increase this mathematical coincidence from one to more than 47 times as they explored the QV created atomic electron shell radii for atoms up to atomic number 7 all based on the QV being the root cause for all of it including the origins of the electron and all other subatomic particles.
BTW, IMO Jim Woodward's Mach-Effect (M-E) conjecture that is based primarily on SRT and GRT, is still in the running for a way to explain his and our test results to date. However the M-E also has its detractors since it requires that instantaneous Wheeler/Feynman radiation reaction forces being required between a local time varying mass and all the other mass/energy in the casually connected universe, since this mechanism is used to balance the M-E's energy & momentum conservation books. In the end analysis though I think that the ME will rest on the quantum nature of space-time, since in Woodward's eyes the gravitational field IS space-time, and in our eyes GRT's space-time is in reality the quantum vacuum that probably has at least 4 spatial dimensions and one time dimension!
Best, Paul March
Thanks for the insight. what does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately? Assuming all the testing currently being done is successful and you get a successful set of replications from other labs. The only thing we would be able to conclusively claim is that the device, built as describes, provides thrust. How does Dr. White plan to show that the device behaves as described by his theory? Also, if Dr. White cannot prove that his theory completely explains the observations, what would be the next steps to find an explanation for the observation? And would we need to have such a theory before we begin using this thing in well defined use cases like ISS or satelite station keeping?
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
First off congratulations, and thank you very much for the information.
One question though. The use of a dummy load to the best of my understanding provides evidence to support that the thrust measurement device is not generating false positive data. Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?
Birchoff:
"Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?"
Yes and yes. In fact it was one of the requests made by the blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer. Even if will take a new mounting arrangement to get it accomplished.
Overall though the blue ribbon panel's experimentalists appeared to be pleased with our previous and upcoming lab work. However they ripped into Sonny's QVF/MHD conjecture because it relies on the quantum vacuum being mutable and engineer-able whereas the current physics mainstream thinks that the quantum vacuum is an immutable ground energy state of the universe that can-NOT be used to convey energy or momentum as proposed by Dr. White. However they brushed aside Sonny's QVF based derivation of the Bohr hydrogen atom electron radius as a "mathematical coincidence" and didn't have a word to say what the Casimir effect and other quantum vacuum phenomenon were caused by, that can only occur only if the QV is mutable and can convey energy and momentum. So Sonny and Jerry Vera took it upon themselves last fall to increase this mathematical coincidence from one to more than 47 times as they explored the QV created atomic electron shell radii for atoms up to atomic number 7 all based on the QV being the root cause for all of it including the origins of the electron and all other subatomic particles.
BTW, IMO Jim Woodward's Mach-Effect (M-E) conjecture that is based primarily on SRT and GRT, is still in the running for a way to explain his and our test results to date. However the M-E also has its detractors since it requires that instantaneous Wheeler/Feynman radiation reaction forces being required between a local time varying mass and all the other mass/energy in the casually connected universe, since this mechanism is used to balance the M-E's energy & momentum conservation books. In the end analysis though I think that the ME will rest on the quantum nature of space-time, since in Woodward's eyes the gravitational field IS space-time, and in our eyes GRT's space-time is in reality the quantum vacuum that probably has at least 4 spatial dimensions and one time dimension!
Best, Paul March
Thanks for the insight. what does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately? Assuming all the testing currently being done is successful and you get a successful set of replications from other labs. The only thing we would be able to conclusively claim is that the device, built as describes, provides thrust. How does Dr. White plan to show that the device behaves as described by his theory? Also, if Dr. White cannot prove that his theory completely explains the observations, what would be the next steps to find an explanation for the observation? And would we need to have such a theory before we begin using this thing in well defined use cases like ISS or satelite station keeping?
Birchoff:
"What does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately?"
Exactly what he and I have been doing. Fleshing out his QVF conjecture in papers for the appropriate peer reviewed journals. He is also continuing the generation of the COMSOL E&M and QVF based C++ plasma code that will allow us to compare the resonant cavity lab results with the QVF based force predictions using the volume integral of the ejected semi-virtual e/p pairs for the resonant cavity geometry in question.
We have already performed the first step along this path with the preliminary results I provided in an earlier post today. In that slide which is based on the copper frustum cavity running in its TM212 mode with 50W of 1,937.188 MHz RF power applied, we showed that the predicted thrust that took over 18 hours to run the 150k time samples on an i5 PC, was 54uN and the average for five real data runs at 50W was 55uN. Is that another mathematical coincidence? I don't think so, but we won't know for sure until I have time to compare the rest of the 30W, 40W, and 60W averages on the attached slide with the same computer code that will take 17 hours to run on my lab PC for each additional example. We will also be looking at modeling and comparing the results of the Cannae test articles we tested in 2013 & 2014, along with the Shawyer/Chinese EM-Drive results with and without dielectrics in the resonant cavities. If our plasma code predictions nail all those tests to say within +/-10% of the experimental results then we can start using it to optimize the thrust output of these QVF/MHD based thrusters.
BTW, it appears that the dielectric discs may act as QV e/p pair reflectors that aid in the conical frustum shape's force symmetry breaking and force rectification process. Left to its own devices, the QV e/p pair spray generated by the applied RF energy tends to want to go in all directions instead of the desired tightly collimated unidirectional propellant beam that goes in one direction while the thruster back-reacts in the opposite direction according to Newton's third law.
Best, Paul March
BTW, it appears that the dielectric discs may act as QV e/p pair reflectors that aid in the conical frustum shape's force symmetry breaking and force rectification process. Left to its own devices, the QV e/p pair spray generated by the applied RF energy tends to want to go in all directions instead of the desired tightly collimated unidirectional propellant beam that goes in one direction while the thruster back-reacts in the opposite direction according to Newton's third law.
Best, Paul March
Birchoff:
"What does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately?"
Exactly what he and I have been doing. Fleshing out his QVF conjecture in papers for the appropriate peer reviewed journals. He is also continuing the generation of the COMSOL E&M and QVF based C++ plasma code that will allow us to compare the resonant cavity lab results with the QVF based force predictions using the volume integral of the ejected semi-virtual e/p pairs for the resonant cavity geometry in question.
...
Rodal:
As a follow up to my previous post and in the spirit of open disclosure, I'm including our last null-thrust test that ran the RF amp at 10.0Adc while its RF power was being dissipated in a 100W, 50 ohm dummy load positioned in place of the test article on the torque pendulum (TP), a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator. Apparently the RF amp's internal gas pressure had gone down from 1 Bar to an estimated 10 Torr or less after a few days leaking air in a hard vacuum. And 0.1-to-10.0 Torr is where glow discharges are the easiest to ignite with RF signals. So much for EMPower's "hermetic" sealed RF amplifiers...
Best, Paul March
First off congratulations, and thank you very much for the information.
One question though. The use of a dummy load to the best of my understanding provides evidence to support that the thrust measurement device is not generating false positive data. Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?
Birchoff:
"Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?"
Yes and yes. In fact it was one of the requests made by the blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer. Even if will take a new mounting arrangement to get it accomplished.
Overall though the blue ribbon panel's experimentalists appeared to be pleased with our previous and upcoming lab work. However they ripped into Sonny's QVF/MHD conjecture because it relies on the quantum vacuum being mutable and engineer-able whereas the current physics mainstream thinks that the quantum vacuum is an immutable ground energy state of the universe that can-NOT be used to convey energy or momentum as proposed by Dr. White. However they brushed aside Sonny's QVF based derivation of the Bohr hydrogen atom electron radius as a "mathematical coincidence" and didn't have a word to say what the Casimir effect and other quantum vacuum phenomenon were caused by, that can only occur only if the QV is mutable and can convey energy and momentum. So Sonny and Jerry Vera took it upon themselves last fall to increase this mathematical coincidence from one to more than 47 times as they explored the QV created atomic electron shell radii for atoms up to atomic number 7 all based on the QV being the root cause for all of it including the origins of the electron and all other subatomic particles.
BTW, IMO Jim Woodward's Mach-Effect (M-E) conjecture that is based primarily on SRT and GRT, is still in the running for a way to explain his and our test results to date. However the M-E also has its detractors since it requires that instantaneous Wheeler/Feynman radiation reaction forces being required between a local time varying mass and all the other mass/energy in the casually connected universe, since this mechanism is used to balance the M-E's energy & momentum conservation books. In the end analysis though I think that the ME will rest on the quantum nature of space-time, since in Woodward's eyes the gravitational field IS space-time, and in our eyes GRT's space-time is in reality the quantum vacuum that probably has at least 4 spatial dimensions and one time dimension!
Best, Paul March
Thanks for the insight. what does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately? Assuming all the testing currently being done is successful and you get a successful set of replications from other labs. The only thing we would be able to conclusively claim is that the device, built as describes, provides thrust. How does Dr. White plan to show that the device behaves as described by his theory? Also, if Dr. White cannot prove that his theory completely explains the observations, what would be the next steps to find an explanation for the observation? And would we need to have such a theory before we begin using this thing in well defined use cases like ISS or satelite station keeping?
Birchoff:
"What does Dr. White believe he has to do in order to prove or disprove that his conjecture explains the behavior observed when the truncated frustum is energized appropriately?"
Exactly what he and I have been doing. Fleshing out his QVF conjecture in papers for the appropriate peer reviewed journals. He is also continuing the generation of the COMSOL E&M and QVF based C++ plasma code that will allow us to compare the resonant cavity lab results with the QVF based force predictions using the volume integral of the ejected semi-virtual e/p pairs for the resonant cavity geometry in question.
We have already performed the first step along this path with the preliminary results I provided in an earlier post today. In that slide which is based on the copper frustum cavity running in its TM212 mode with 50W of 1,937.188 MHz RF power applied, we showed that the predicted thrust that took over 18 hours to run the 150k time samples on an i5 PC, was 54uN and the average for five real data runs at 50W was 55uN. Is that another mathematical coincidence? I don't think so, but we won't know for sure until I have time to compare the rest of the 30W, 40W, and 60W averages on the attached slide with the same computer code that will take 17 hours to run on my lab PC for each additional example. We will also be looking at modeling and comparing the results of the Cannae test articles we tested in 2013 & 2014, along with the Shawyer/Chinese EM-Drive results with and without dielectrics in the resonant cavities. If our plasma code predictions nail all those tests to say within +/-10% of the experimental results then we can start using it to optimize the thrust output of these QVF/MHD based thrusters.
BTW, it appears that the dielectric discs may act as QV e/p pair reflectors that aid in the conical frustum shape's force symmetry breaking and force rectification process. Left to its own devices, the QV e/p pair spray generated by the applied RF energy tends to want to go in all directions instead of the desired tightly collimated unidirectional propellant beam that goes in one direction while the thruster back-reacts in the opposite direction according to Newton's third law.
Best, Paul March
One approach to conserve momentum is to consider spaceSo that approach is out because it is in opposition to Michelson-Morely.
itself as the reaction mass. This approach evokes the old idea
of an "ether." To be strictly consistent with empirical
evidence, such as the Michelson-Morely experiment, any
further research to revisit the idea of an ether would have to
impose the condition that an ether is electromagnetically
Lorentz invariant- Note that this condition is a characteristic
of the ZPF [7].
An alternative to considering space as the reaction mass isThat sounds pretty good, but it leaves out two very important "sources" of inertia, which to Mach, were not directly observable to him. The quantum world, and the bound energy within the nucleus of atoms, and of course the QV. The philosophy of Mach valued what was directly observable. In modern times, materialism and physicalism are relics. So this approach is incomplete, thus a no go.
to further develop Mach's Principle. Mach's Principle asserts
that surrounding matter gives rise to inertial frames, and that
the inertial frames are somehow connected to the surrounding
matter [9]. Mach wrote that although he felt a connection to
the surrounding matter was required for the property of inertia
to be detectable, he also admitted that such a treatment was
not necessary to satisfactorily describe the laws of motion
[20]. Specifically, to be useful for propulsion physics, a
formalism of Mach's Principle is required that provides a
means to wansmit reaction forces to surrounding matter. This
implies developing a quantitative description for how the
surrounding matter creates an inertial frame, and how pushing
against that flame with a space drive is actually pushing
against the distant surrounding matter.
It is also possible to consider the very structure ofMuch better....
spacetime itself as a candidate for propulsive interactions. If it
were possible, for example, to create asymmetries in the very
properties of spacetime which give rise to inertial frames, it
may be possible to create net inertial forces. This is similar
to the"warp drive" suggested by Alcubierre [4]
In that case, the fluctuation-mediated attraction between the atoms becomes orders of magnitude stronger than in free space. Usually, the force decreases rapidly with increasing distance between the atoms. Due to the transmission line, it falls off with one over the distance cubed, instead of one over the seventh power of the distance, as in the usual case.
Either way, I know there is vacuum energy difference in potential from the top to the bottom of the cavity and those relative differences are all that matter. From there, after mathematical conversion to momentum, it doesn't take a mathematician to know that the competing vacuum and RF momentum contributions to the dielectric aren't exactly equal.Anyway it is just words without math to back it up.
Folks:
If the quantum vacuum is degradable and malleable as we think it should be, then to conserve momentum a QV wake has to be generated in the QV media as a Q-Thruster goes by just like a ship's propeller leaves a disturbance in the water as it goes by. We think that the density of the QV is normally around its cosmological average of 9.1x10^-27 kg/m^3, but its density can be greatly increased by the presence of E&M fields and especially very strong and fast time-varying E&M fields that occur is microwave resonant cavities with large Quality Factors greater than say 1,000, or around elementary charged particles like electrons or protons where the QV density goes up to nuclear mass density as you approach the surface of the particle. Suggest anything? However in the paper we are now trying to get published with no takers so far, we find that the QV density should drop off very rapidly from a high density volume like a proton and in fact it follows the same drop off in density with distance as the Casimir effect does, i.e., 1 / r^4 where r = the distance from the resonant cavity boundary. With that being the case it would be near impossible to detect the QV wake behind a Q-Thruster only generating milliNewtons or Newtons or even in tens of Newtons.
So what's to do? To detect a QV wake from a Q-thruster at even short distances from the source we think we will have to use another RF excited resonant cavity in a form of QV parametric amplification that is designed to produce a high density QV state just like in a Q-Thruster, but not to produce thrust. Instead it will be optimized to monitor its time varying QV density as various very weak QV wake fields come in, are amplified and detected, then pass out of it again to go back to the low density QV state once again. This has some interesting implications especially when you finish reading the attached paper from a PhD from Rice University here in Houston.
Last topic for the night for me. Someone on this list asked if one could extract energy from the QV. If the QV is GRT space-time, and space-time is the cosmological gravitational field that is created by all the causally connected mass/energy in our section of the universe, then we live in a high pressure sea of gravitational energy. Now if the QV energy state is degradable and locally changeable, then one can posit the possibility of a thermodynamic energy conversion cycle that can extract energy from a pressure difference created in this QV media relative to the QV background average pressure, with a net decrease in this universal gravitational pressure or temperature reflective of the amount of energy so extracted. And try to remember that gravitational energy is negative energy. I'll leave the rest to you folks to draw your own conclusions from what this might mean...
Best, Paul March
Folks:
If the quantum vacuum is degradable and malleable as we think it should be, then to conserve momentum a QV wake has to be generated in the QV media as a Q-Thruster goes by just like a ship's propeller leaves a disturbance in the water as it goes by. We think that the density of the QV is normally around its cosmological average of 9.1x10^-27 kg/m^3, but its density can be greatly increased by the presence of E&M fields and especially very strong and fast time-varying E&M fields that occur is microwave resonant cavities with large Quality Factors greater than say 1,000, or around elementary charged particles like electrons or protons where the QV density goes up to nuclear mass density as you approach the surface of the particle. Suggest anything? However in the paper we are now trying to get published with no takers so far, we find that the QV density should drop off very rapidly from a high density volume like a proton and in fact it follows the same drop off in density with distance as the Casimir effect does, i.e., 1 / r^4 where r = the distance from the resonant cavity boundary. With that being the case it would be near impossible to detect the QV wake behind a Q-Thruster only generating milliNewtons or Newtons or even in tens of Newtons.
So what's to do? To detect a QV wake from a Q-thruster at even short distances from the source we think we will have to use another RF excited resonant cavity in a form of QV parametric amplification that is designed to produce a high density QV state just like in a Q-Thruster, but not to produce thrust. Instead it will be optimized to monitor its time varying QV density as various very weak QV wake fields come in, are amplified and detected, then pass out of it again to go back to the low density QV state once again. This has some interesting implications especially when you finish reading the attached paper from a PhD from Rice University here in Houston.
Last topic for the night for me. Someone on this list asked if one could extract energy from the QV. If the QV is GRT space-time, and space-time is the cosmological gravitational field that is created by all the causally connected mass/energy in our section of the universe, then we live in a high pressure sea of gravitational energy. Now if the QV energy state is degradable and locally changeable, then one can posit the possibility of a thermodynamic energy conversion cycle that can extract energy from a pressure difference created in this QV media relative to the QV background average pressure, with a net decrease in this universal gravitational pressure or temperature reflective of the amount of energy so extracted. And try to remember that gravitational energy is negative energy. I'll leave the rest to you folks to draw your own conclusions from what this might mean...
Best, Paul March
Thank you for participating in the forum Paul. As far as the paper goes, why not publish publicly and let your peers see it and validate it without the "Star Chamber" reviewers?
Regarding the QV wake, does measuring it really matter in terms of validity if tens of Newtons of thrust (or more) are predictably being measured?
[Serious question]
As to your third to last sentence. Woah!!!.......
@ Mulletron
["As far as the difference in vacuum energy goes, we've discussed the possibility that there exists a "more negative" energy condition at the small end of the cavity WRT the large end. Less modes fit small end vs large end. No calculations were made."]
This is the dispersion relation calculation. The evaluation is made as the difference from one end of the cavity to the other. A "boost" is made to an accelerated frame of reference which eliminates that difference, ie. "v is everywhere close to c" This is just the "trivial" approximation as in:
* Hydrodynamics of the Vacuum_0409292v2.pdf
" However, the vacuum is a Lorentz invariant medium; it has no rest frame. The appropriate frame for the NFA is determined solely by the initial conditions. If in some frame the NFA conditions are satisfied at t = 0 then they will remain satisfied at all later times. One may trivially take a NFA solution and boost it by a large Lorentz boost to obtain an approximate solution to the original relativistic equations in which v is everywhere close to 1. Only when the range of v values is a significant fraction of unity is it necessary to abandon the NFA and return to the relativistic equations, (4.26, 4.27)."
The (static) force then appears as the equivalent "weight" of the photons in the AFR.
Although the flow velocity is nonrelativistic (v ≪ 1), disturbances tend to “propagate” superluminally, at 1/v. Hence, the NFA here is not a normal nonrelativistic reduction. The resulting equations are “anti-Galilean” invariant...This is certainly strange, and takes some getting used to, but one should simply view it(Bold added for emphasis)
as an approximation to the full Lorentz transformations, valid in the stated context. One
is used to dealing with small objects that move slowly, so that their density distributions
vary rapidly in space, but slowly in time. In the present case one is dealing with large
objects, slowly varying in space, but relatively rapidly varying in time. This is related to
the fact that the Higgs vacuum, as a spontaneous Bose-Einstein condensate, has almost
all its particles in the same quantum state. Small disturbances of this state involve vast
numbers of particles, spread over long distances, all moving nearly in lockstep, so that
the disturbance varies only slowly with position while the whole collective has the same,
relatively rapid time dependence.
The measured power applied to the test article was measured to be 2.6 watts, and the (net) measured thrust was 55.4 micronewtons. With an input power of 2.6 watts, correcting for the quality factor, the predicted thrust is 50 micronewtons. However, since the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.
approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz
BTW, we have found that both the TE and TM E&M modes of this copper frustum can produce a thrust signature, but so far the TM modes appear to be the better performer, at least for the few modes we have been able to study to date.
The tapered thruster has a mechanical design such that it will be able to hold pressure at 14.7 pounds per square inch (psi) inside of the thruster body while the thruster is tested at vacuum to preclude glow discharge within the thruster body while it is being operated at high power.
Paul, so last summer it was reported that TE012 was a top performer yet difficult to work with:
...
The landscape appears to have changed somewhat:Quoteapprox. +50 micro-Newton (uN) with 50W at 1,937.115 MHzQuoteBTW, we have found that both the TE and TM E&M modes of this copper frustum can produce a thrust signature, but so far the TM modes appear to be the better performer, at least for the few modes we have been able to study to date.
So a couple questions from this. It appears that TM modes are the top dogs now and at the same time performance has gone down significantly since vacuum testing began. See table below for what I mean. TM212 reported now vs TM211 reported then? Do you have any insight about this? Did the vacuum serve to eliminate artifact thrust signals significantly?
Folks:
If the quantum vacuum is degradable and malleable as we think it should be, then to conserve momentum a QV wake has to be generated in the QV media as a Q-Thruster goes by just like a ship's propeller leaves a disturbance in the water as it goes by. We think that the density of the QV is normally around its cosmological average of 9.1x10^-27 kg/m^3, but its density can be greatly increased by the presence of E&M fields and especially very strong and fast time-varying E&M fields that occur is microwave resonant cavities with large Quality Factors greater than say 1,000, or around elementary charged particles like electrons or protons where the QV density goes up to nuclear mass density as you approach the surface of the particle. Suggest anything? However in the paper we are now trying to get published with no takers so far, we find that the QV density should drop off very rapidly from a high density volume like a proton and in fact it follows the same drop off in density with distance as the Casimir effect does, i.e., 1 / r^4 where r = the distance from the resonant cavity boundary. With that being the case it would be near impossible to detect the QV wake behind a Q-Thruster only generating milliNewtons or Newtons or even in tens of Newtons.
So what's to do? To detect a QV wake from a Q-thruster at even short distances from the source we think we will have to use another RF excited resonant cavity in a form of QV parametric amplification that is designed to produce a high density QV state just like in a Q-Thruster, but not to produce thrust. Instead it will be optimized to monitor its time varying QV density as various very weak QV wake fields come in, are amplified and detected, then pass out of it again to go back to the low density QV state once again. This has some interesting implications especially when you finish reading the attached paper from a PhD from Rice University here in Houston.
Last topic for the night for me. Someone on this list asked if one could extract energy from the QV. If the QV is GRT space-time, and space-time is the cosmological gravitational field that is created by all the causally connected mass/energy in our section of the universe, then we live in a high pressure sea of gravitational energy. Now if the QV energy state is degradable and locally changeable, then one can posit the possibility of a thermodynamic energy conversion cycle that can extract energy from a pressure difference created in this QV media relative to the QV background average pressure, with a net decrease in this universal gravitational pressure or temperature reflective of the amount of energy so extracted. And try to remember that gravitational energy is negative energy. I'll leave the rest to you folks to draw your own conclusions from what this might mean...
Best, Paul March
Thank you for participating in the forum Paul. As far as the paper goes, why not publish publicly and let your peers see it and validate it without the "Star Chamber" reviewers?
Regarding the QV wake, does measuring it really matter in terms of validity if tens of Newtons of thrust (or more) are predictably being measured?
[Serious question]
As to your last few sentences. Woah!!!.......
Rodal:
Look at the copper frustum part-2 COMSOL & IR thermal study that I submitted to this group yesterday for an answer to your "Have you experimentally verified that we are using the TM212 mode as predicted by our COMSOL simulations? The answer BTW is yes for the TM212 mode, but no for the TE012 mode, but since COMSOL predicted the right PE loaded resonant frequency for the TE212 mode as verified by my IR camera studies 1 & 2 of the copper frustum, I would assume that it got it right for the TE012 mode as well. In fact I should have provided you my IR study-1 first, so find it attached.
Best, Paul M.
Rodal:
Look at the copper frustum part-2 COMSOL & IR thermal study that I submitted to this group yesterday for an answer to your "Have you experimentally verified that we are using the TM212 mode as predicted by our COMSOL simulations? The answer BTW is yes for the TM212 mode, but no for the TE012 mode, but since COMSOL predicted the right PE loaded resonant frequency for the TE212 mode as verified by my IR camera studies 1 & 2 of the copper frustum, I would assume that it got it right for the TE012 mode as well. In fact I should have provided you my IR study-1 first, so find it attached.
Best, Paul M.
Paul, thank you. This is the first time I see the attached IR study ("Comparison of COMSOL Predictions of Copper Frustrum Heat Dissipation with Dec 30 IR Data") . It was an excellent idea for NASA to conduct this experimental study to verify the TM212 mode. I congratulate you for that because it is of the utmost importance to understand the actual mode shapes being excited.
I attach the TM21 mode for a cylindrical cavity for comparison with TM21 in the truncated cone
Magnetic field: - - - - - - dashed lines
Electric field: _______solid lines
PS: Concerning whether COMSOL's discretization predicting TE012 was correct, my attitude (based on conducting experiments and numerical analysis) is always I'm from Missouri "show me" :), so I would rather also have experimental verification for that experiment as well. But considering your tight budget constraints, you deserve congratulations for what has been done.
(Bold added for emphasis)
Numerous COMSOL® analysis runs also indicated a strong dependency between thrust magnitude and antenna type, location, orientation, and number of antenna feeds. Slight changes in antenna design and number of feeds changed the COMSOL® thrust prediction by a factor of three which forced our team to implement tighter configuration control protocols during testing to ensure close representation of as built hardware to the analyzed configuration.
Finally, our experience with the TE012 mode indicated that it is important to design the RF prototype such that any target mode of operation is as isolated as possible in the frequency domain to help ensure that the system can be effectively tuned manually. This also protects for the ability to implement and use a phase lock loop (PLL) automated frequency control circuit. Due to the slow process commensurate with manual tuning, our future test articles will make use of a PLL whenever practical in order to increase the amount of data that can be collected for a given test article configuration and operating condition during a given amount of test time
the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.(Bold added for emphasis)
TM212 mode shape at 1.937188 GHz (Jan 2015 data (with the dielectric))
QuoteTM212 mode shape at 1.937188 GHz (Jan 2015 data (with the dielectric))
That comsol plot above says 1946.647. Where's the disconnect between numbers reported I wonder? Also unless comsol is taking into account all the little intricacies like heat expansion, bowing and buckling, simulation won't yield an exact result in reality.
In that slide which is based on the copper frustum cavity running in its TM212 mode with 50W of 1,937.188 MHz RF power applied
I get that, but with a cavity loaded with a dielectric, you can't add up wavelengths trying to satisfy E field requirements like we do with empty waveguides. With the dielectric inserted, there is a dielectric resonator inside the cavity resonator which means the solution is more complicated to figure out by hand.I am not figuring out the solution by hand. I am using Mathematica. Also, I have based my above statements on my extensive experience developing Finite Element formulations for nonlinear analysis, writing code for Finite Element programs and using commercial Finite Element codes to solve practical problems.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634742;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634740;image)Wow, what a day. Thanks Paul March. Seriously thanks.
All:
Please note that our first COMSOL analyst who was volunteering his time for this activity while holding down his NASA day job, transcribed the dimensions for the copper frustum PE discs incorrectly when he did the analysis for the TE012 mode. He used 6.0" OD by 1.0" thick whereas the actual dimensions for the PE discs was 6.13" OD by 1.062" thick. The extra volume in the two PE discs lowered the actual observed resonant frequencies for all the resonant modes in the cavity down by about 8-to-10 MHz from COMSOL calculated. When you have to beg for help, one can't be too critical of the results. As to the TM212 mode analysis it was performed by another volunteer, so again I'm not going to complain that he didn't get these calculated frequencies spot on to what was measured with our Agilent Field-Fox Vector Network Analyzer (VNA) measured.
Rodal:
The next time we look at the TE012 mode I will perform the same IR camera survey I did for the TM212 mode. The reason I didn't do the IR camera survey of the TE012 mode the first time around was that we didn't have that capability during March of 2014 when we ran that test series, since the IR camera didn't come along until the summer of 2014.
Best, Paul M.
If I am following the last couple pages correctly at all, it seems that the cavity dimensions relative to the frequency is of supreme importance to making this device work.Sounds like it may make them tricky to reproduce at least initially.
I am reminded of the precision machining required to properly re-bore cylinders in car engines: get that wrong, even by a very tiny fraction, and the engine won't run properly. I've known a number of people who didn't get that right. It seems the same degree of precision is required here.
If I am following the last couple pages correctly at all, it seems that the cavity dimensions relative to the frequency is of supreme importance to making this device work.Sounds like it may make them tricky to reproduce at least initially.
I am reminded of the precision machining required to properly re-bore cylinders in car engines: get that wrong, even by a very tiny fraction, and the engine won't run properly. I've known a number of people who didn't get that right. It seems the same degree of precision is required here.
If I am following the last couple pages correctly at all, it seems that the cavity dimensions relative to the frequency is of supreme importance to making this device work.
I am reminded of the precision machining required to properly re-bore cylinders in car engines: get that wrong, even by a very tiny fraction, and the engine won't run properly. I've known a number of people who didn't get that right. It seems the same degree of precision is required here.
@ RODALYes, and I am working on an exact solution including the dielectric as well.
Did you say you had an exact analytic solution for the truncated cavity ?
@ RODAL
Can you put it in terms of a dispersion relation that can be evaluated at the ends ?
@ RODAL
That should keep you busy ! (but worth it)
@ RODAL
Do you have the dielectric constants (@ freq) and the dimensions ?
...
Best, Paul M.
Just want to put this out there in case it helps. During all the research of literature concerning QV momentum, these two materials came up again and again. Cr2O3 and FeGaO3. Or if that is too high speed, PTFE or PVDF. To get over the 100uN hump, it might be time to dump the PE and try something else.Or if that doesn't work...
...
Best, Paul M.
Paul : did NASA (or an outside lab) measure with a dielectrometer the dielectric constant and the tan delta of the High Density PE you used for the dielectric ?
Otherwise, do you have the relative electrical permittivity and the tan delta of the HD PE at a frequency of ~ 2 GHz at the temperatures experienced during the experiment, from some other source ?
If not, do you have the molecular weight of the HD PE used for the dielectric or some form of further characterization from the dielectric supplier ?
Thanks
Just want to put this out there in case it helps. During all the research of literature concerning QV momentum, these two materials came up again and again. Cr2O3 and FeGaO3. Or if that is too high speed, PTFE or PVDF. To get over the 100uN hump, it might be time to dump the PE and try something else.Or if that doesn't work...
Why should there be a target to achieve a given thrust with a single EMDrive?
Why not just achieve the required thrust at Glenn by using n drives to add up to the required thrust?
For 100uN one needs two EM Drives each providing 50uN, or three EM Drives each providing 33uN and so on
So... I haven't really done a good long read of this thread in a huge amount of time, since before thread 1 reached a few pages long, even. Would it be possible for someone to produce a 1-2 paragraph summary of what's been going on here over the past few months? Are we... building our own EmDrive, now?
1) We are exploring the validity of the claims of the different experimenters (NASA in the USA, Shawyer in the UK and Juan Yang in China) by systematically analyzing their experiments.
2) Some of the people in this forum are also designing and working to make their own prototypes and experiments.
3) One of the people in this forum (@NotSoSureOfIt), has made an outstanding contribution by independently deriving an equation that is not far from the claimed experimental results.
4) There are a number of possible physical reasons for the experimental results to be valid for space propulsion as well as for the results to be an experimental artifact that may not produce any propulsion in space.
5) There have been no further reports from NASA on the experiments that were supposed to be replicated at their other centers (JPL and Glenn) or at John Hopkins University. Actually @wembley, who is an aerospace technology reporter, reports that it is his opinion that NASA has a "news blackout" on this matter, and China's Juan Yang is not saying much either. The Chinese seem to be much further along than NASA, as they reported much greater thrust and they have conducted more thorough experiments (including being the first to numerically report the effects of temperature and temperature gradients with thermocouples embedded in the metal). Shawyer in the UK seems to be much further ahead than NASA as he claims he is exploring a superconducting design. Shawyer (UK) made a presentation in Canada late last year where he showed his latest design (using superconductivity) which he claims will result in much greater thrust/PowerInput (see image below).
Is copper the ideal material for the frustum? Or are there even better materials, theoretically?
Is copper the ideal material for the frustum? Or are there even better materials, theoretically?
I think maybe it was Mulletron that previously pointed out this paper:
https://hal.archives-ouvertes.fr/hal-01074608/document (https://hal.archives-ouvertes.fr/hal-01074608/document)
The conjecture in that paper is that building the larger diameter plate (R1) out of metglas 2714A, a significant amplification of the effect would result. Perhaps there is a courageous person or group with some funds to put this to the test. It would be interesting to see an experiment with the partial metglas construction to rule the theory in or out.
Given that metglas 2714A is a room-temperature material, it would be considerably easier to achieve an amplification that way than lining the interior of the test article with superconducting film and cooling to liquid nitrogen temperatures.
Is copper the ideal material for the frustum? Or are there even better materials, theoretically?
I think maybe it was Mulletron that previously pointed out this paper:
https://hal.archives-ouvertes.fr/hal-01074608/document (https://hal.archives-ouvertes.fr/hal-01074608/document)
The conjecture in that paper is that building the larger diameter plate (R1) out of metglas 2714A, a significant amplification of the effect would result. Perhaps there is a courageous person or group with some funds to put this to the test. It would be interesting to see an experiment with the partial metglas construction to rule the theory in or out.
Given that metglas 2714A is a room-temperature material, it would be considerably easier to achieve an amplification that way than lining the interior of the test article with superconducting film and cooling to liquid nitrogen temperatures.
As far as building the cavity itself, copper is good enough. It is easy to get and work with and has great electrical properties. Anything better would be precious metals which isn't worth the money. And superconductors aren't exactly "home workshop" compatible for most.
As far as something in place of the polyethylene dielectric, I'd suggest something that exhibits a higher relative permittivity or even a material that exhibits magnetochiral dichroism. http://www.academia.edu/1084905/Probing_magnetochirality
Copper may very well be good enough for the cavity itself. Or maybe not. There is at least a theory that metglass would be better if used for one of the frustrum's plates (i.e., the larger plate). Do you see a reason why someone shouldn't make an experiment along these lines?
If the microwave source radiates pulses with 10 megawatts power then the thrust can.
reach up to 100kN.
Any time the K/Ko exceeds 1.0 … is the point where almost all physicists will pause, turn their heads and say, what? Yep. The K/Ko in the lowest wattage, highest Q experiment was not just a little bit greater than 1.0, but was an almost implausible 6,388× larger.
If this were SETI, we'd call that the “Wow! signal”
Interesting conjecture. Did the author of the paper advocating the use of Metglas 2714A take into account that its ultra-high magnetic permeability which he quotes in the paper (apparently for his calculations) as μ=1,000,000 occurs at very low frequencies and that its magnetic permeability decreases significantly at higher frequencies ?Is copper the ideal material for the frustum? Or are there even better materials, theoretically?
I think maybe it was Mulletron that previously pointed out this paper:
https://hal.archives-ouvertes.fr/hal-01074608/document (https://hal.archives-ouvertes.fr/hal-01074608/document)
The conjecture in that paper is that building the larger diameter plate (R1) out of metglas 2714A, a significant amplification of the effect would result. Perhaps there is a courageous person or group with some funds to put this to the test. It would be interesting to see an experiment with the partial metglas construction to rule the theory in or out.
Given that metglas 2714A is a room-temperature material, it would be considerably easier to achieve an amplification that way than lining the interior of the test article with superconducting film and cooling to liquid nitrogen temperatures.
Interesting conjecture. Did the author of the paper advocating the use of Metglas 2714A take into account that its ultra-high magnetic permeability which he quotes in the paper (apparently for his calculations) as μ=1,000,000 occurs at very low frequencies and that its magnetic permeability decreases significantly at higher frequencies ?Is copper the ideal material for the frustum? Or are there even better materials, theoretically?
I think maybe it was Mulletron that previously pointed out this paper:
https://hal.archives-ouvertes.fr/hal-01074608/document (https://hal.archives-ouvertes.fr/hal-01074608/document)
The conjecture in that paper is that building the larger diameter plate (R1) out of metglas 2714A, a significant amplification of the effect would result. Perhaps there is a courageous person or group with some funds to put this to the test. It would be interesting to see an experiment with the partial metglas construction to rule the theory in or out.
Given that metglas 2714A is a room-temperature material, it would be considerably easier to achieve an amplification that way than lining the interior of the test article with superconducting film and cooling to liquid nitrogen temperatures.
See the attached plot, unfortunately the available data ( http://www.metglas.com/assets/pdf/2714a.pdf ) goes up to only 10^5 Hz while the EM Drive operates at 20000 times higher frequency: 2*10^9 Hz. At the much lower frequency of 10^5 Hz the magnetic permeability has decreased by a factor of 50 from the maximum DC permeability of μ =1,000,000 to μ =20,000. If it decreases by another factor of 50 (it will probably decrease more due to the steepening shape of the curve ?) the magnetic permeability at 2*10^9 Hz may be μ ~ 400 instead of 1,000,000.
(Optimistically ?) assuming that μ ~ 400 for Metglas 2714A at 2*10^9 Hz, then the author's prediction of 1,000 times higher "thrust" (?) than Shawyer’s thruster would be reduced by Sqrt[(10^6)/400]=50 times, so that the increase in thrust would be 20 times over Shawyer's experiments (assuming that the author's conjecture and theory are correct, and assuming that the EM Drive can be (practically) tuned to stay in Q resonance at a suitable mode-shape with such a material).
Still, a factor of 20 times higher force is nothing to ignore, if the author's theory is correct, and if the magnetic permeability is at least μ ~ 400 for Metglas 2714A at 2*10^9 Hz, this material may enable to exceed the minimum requirements for testing the Eagleworks frustum at NASA's Glenn.
I still favor direct application of the Equivalence Principle ...night all@Notsosureofit
(Optimistically ?) assuming that μ ~ 400 for Metglas 2714A at 2*10^9 Hz, then the author's prediction of 1,000 times higher "thrust" (?) than Shawyer’s thruster would be reduced by Sqrt[(10^6)/400]=50 times, so that the increase in thrust would be 20 times over Shawyer's experiments (assuming that the author's conjecture and theory are correct, and assuming that the EM Drive can be (practically) tuned to stay in Q resonance at a suitable mode-shape with such a material).
Still, a factor of 20 times higher force is nothing to ignore, if the author's theory is correct, and if the magnetic permeability is at least μ ~ 400 for Metglas 2714A at 2*10^9 Hz, this material may enable to exceed the minimum requirements for testing the Eagleworks frustum at NASA's Glenn.
This paper (http://infoscience.epfl.ch/record/55950/files/76.pdf ) has data up to 30 MHz (that is 67 times lower than the frequency of operation of the EM Drive, hence much closer to the EM Drive's frequency than the data from the manufacturer at 100KHz, considering that the drop of magnetic permeability depends on the Log of frequency, the EM Drive Log frequency is just 1.8 times higher) showing a magnetic relative permeability of μ =6000 at 30 MHz, indicating about μ =2400 at 2*10^9 Hz
If the author's conjecture and theory are correct, this extrapolated value ( μ =2400 at 2*10^9 Hz) would result in an improvement of 1000/Sqrt[(10^6)/2400] = 1000/20.4 = 49 times greater thrust force than Shawyer's experiments.
This information, coupled with the one in the previous post, indicates that that (if Aquino's theory is correct) using amorphous metal (http://en.wikipedia.org/wiki/Amorphous_metal) Metglas 2714A sheet ( http://en.wikipedia.org/wiki/Metglas ) may result in 20 to 50 times greater thrust force than using copper sheet.
(http://www.metglas.com/assets/images/slider4.jpg)
I still favor direct application of the Equivalence Principle ...night all@Notsosureofit
Concerning <<I still favor direct application of the Equivalence Principle >> I would appreciate your comments/observations concerning Univ. of Massachusetts, John F. Donoghue, Barry R. Holstein, R. W. Robinett's 1985 (awarded ?) paper
"The principle of equivalence at finite temperature" (http://www.gravityresearchfoundation.org/pdf/awarded/1984/donoghue_holstein_robinett.pdf)
citation history here:
http://inspirehep.net/record/14777/citations
where they claim to demonstrate that the equivalence principle is violated by radiative corrections to the gravitational and inertial masses at finite temperature. (How about Unruh radiation as per Dr. McCulloch's theory ?).
They argue that this result can be attributed to the Lorentz noninvariance of the finite temperature vacuum.
Max Jammer refers to Donoghue's paper in an authoritative manner with very interesting discussion in pages 138 to 140 of Jammer's classic book "Concepts of Mass in Contemporary Physics and Philosophy" (see: this link http://bit.ly/1y8vaCO )
The fundamental ideas which led to the equivalence principle include the impossibility of defining absolute motion through the vacuum and the indistinguishability of acceleration and gravitational force. However, one can measure absolute velocity and acceleration relative to the heat bath (as has been done for the velocity of the Earth in the 3°K photon distribution left over from the early universe). Thus the conditions under which the equivalence principle was formulated are not met at finite temperature. The fact that we do live in a universe at a nonzero ternperature could in principle have led to unexpected results in the Eotvos experiments if it were not for the fact that the correction is too small to be detected at present temperatures.
@ RODALYes, you are entirely correct. Sorry if my poor wording conveyed that impression. I brought up Donoghue's paper because it may give yet another possibility: escaping the equivalence principle (but the effect appears to be very small )
My understanding was that the Doppler shifted radiation of the cosmic background would constitute an increasing drag (and thus a limit) on the accelerated system, (as Unruh) not that it invalidated the equivalence principle. But, I'll look and see what they say.
@ RODALYes, you are entirely correct. Sorry if my poor wording conveyed that impression. I brought up Donoghoue's paper because it may give yet another possibility: escaping the equivalence principle (but the effect appears to be very small )
My understanding was that the Doppler shifted radiation of the cosmic background would constitute an increasing drag (and thus a limit) on the accelerated system, (as Unruh) not that it invalidated the equivalence principle. But, I'll look and see what they say.
@ RODALYes, you are entirely correct. Sorry if my poor wording conveyed that impression. I brought up Donoghoue's paper because it may give yet another possibility: escaping the equivalence principle (but the effect appears to be very small )
My understanding was that the Doppler shifted radiation of the cosmic background would constitute an increasing drag (and thus a limit) on the accelerated system, (as Unruh) not that it invalidated the equivalence principle. But, I'll look and see what they say.
A quick read but you can probably get their results by using the photon bath as a viscous fluid exchanging energy at a given temperature. Nice quantum argument. In any event, the cosmic background does not constitute a temperature "bath" under velocity (or acceleration) because of the vector form (directionality) of the velocity. Have to look at the citations..
It appears that TM modes are the top dogs now and at the same time performance has gone down significantly since vacuum testing began.The answer to the bold part in particular. I don't think the answer is fully due to the elimination of air currents, as the thrust signature rise and fall times were instantaneous during the non vacuum tests reported last summer.
BTW, the copper frustum is vented, so its internal pressure matches the chamber pressure after a short time period at vacuum.
We report the first observation of the anisotropy of the velocity of light, induced in a gas by electricThis alone is an amazing result. Note that it is an observation.
and magnetic fields.....Using a high finesse ring cavity, we have
measured the magneto-electric directional anisotropy of molecular Nitrogen at ambient temperature
and atmospheric pressure
Moreover, the same effect is expected in quantum vacuum......Our long term goal is to search forThe QV prediction would be huge if confirmed.
the magneto-electric directional anisotropy of quantum.
..I don't think the answer is fully due to the elimination of air currents, as the thrust signature rise and fall times were instantaneous during the non vacuum tests reported last summer. ...That "instantaneous" length of time was long enough, that it could be fully explained as a thermal instability, as I showed in my report. Thermal instability that does not need thermal convection as a transport mechanism. The IR experimental measurements were done without air inside or outside the EM Drive, and the COMSOL analysis showing heating of the big diameter surface was modeled without air inside or outside the EM Drive, is that right?
...
I accidentally stumbled upon this report:
https://hal.archives-ouvertes.fr/hal-00551421v1/documentQuoteWe report the first observation of the anisotropy of the velocity of light, induced in a gas by electricThis alone is an amazing result. Note that it is an observation.
and magnetic fields.....Using a high finesse ring cavity, we have
measured the magneto-electric directional anisotropy of molecular Nitrogen at ambient temperature
and atmospheric pressure
...
As far as heat goes, Eagleworks repeatedly reported that heat was controlled for and wasn't an issue. So I'm forced to trust the experiment was legit. Vacuum eliminates hot air currents but not radiation.
A simple falsification of all this transferring momentum from the qv business is simply to evacuate all the air from the resonant cavity and remove the dielectric and see if the thrust goes away.
Is 50 watts worth of ir radiation enough to mimic the thrust signal? You established that the measured thrust is in excess of a photon rocket. So all that is left is the thermal instability you mentioned. Hope Paul comments on that.
Is 50 watts worth of ir radiation enough to mimic the thrust signal? You established that the measured thrust is in excess of a photon rocket. So all that is left is the thermal instability you mentioned. Hope Paul comments on that.
I wish that NASA Glenn would pay, now, to have several EM Drives tested in their unit, to be able (in principle) to generate enough thrust force to get a reading at Glenn with all the drives together being pointed in the same direction. My reading of what Paul March wrote is that this would mean at least 3 EM Drives. With three (or more) EM Drives one could also conduct several interesting tests with orientation of each drive: all of them oriented in parallel, oriented in series (is there any measurable wake ?), oriented opposite to each other, etc.
Edison conducted >10,000 experiments for the incandescent light bulb, thousands of tests for the alkaline battery, etc.
Could the thermal thrust theory be tested by insulating the device with some sort of thermal blanket, such as Mylar?Thermal instability results from the electromagnetic fields heating the interior surfaces of the (big diameter) copper surface. Since the small diameter surface is shielded by the HD PE dielectric polymer, what gets heated is the big diameter interior surface (and, by thermal conduction, the exterior surface as well, as shown in the IR measurement, attached below). I understand that the IR measurement was done from the outside, with the IR camera looking at the composite polymer surface of the circuit board surface they had on the exterior of the big diameter flat end. Since this composite polymer has much lower thermal conductivity and much lower thermal diffusivity than copper, please take into account that these IR measurements represent a temperature and temperature gradients significantly lower than those present on the inner (copper) surface of the big diameter flat end. In other words, the composite polymer circuit board surface being measured with the IR camera acts like an insulating surface concealing the higher temperature of the inner copper surface.
I have shown that a thermo-mechanical effect (thermal buckling of the base of the truncated cone) can account for some of the "anomalous" results reported by NASA's Brady et.al. I have shown that the buckling time is under 1 second for copper thicknesses under 0.84 mm (33 thousands of an inch) and just 2.6 watt power input. I have shown that the buckling temperature increase required is of the order of 1 deg C or less. I have shown that thermal buckling can produce a sudden output response.(Bold added for emphasis)
I have shown that the calculated buckling forces agree with the measured force (55.4 microNewtons). The buckling force is a very strong function of plate thickness (to the fourth power), to prevent thermal buckling from occurring it suffices to have a thicker copper sheet (1/8 inch or thicker would completely prevent this thermal buckling under these input powers).
This thermal buckling effect does not depend at all on air as a conducting medium; it will take place in a complete vacuum as well
Could the thermal thrust theory be tested by insulating the device with some sort of thermal blanket, such as Mylar?Thermal instability results from the electromagnetic fields heating the interior surfaces of the (big diameter) copper surface. Since the small diameter surface is shielded by the HD PE dielectric polymer, what gets heated is the big diameter interior surface (and, by thermal conduction, the exterior surface as well, as shown in the IR measurement, attached below). I understand that the IR measurement was done from the outside, with the IR camera looking at the composite polymer surface of the circuit board surface they had on the exterior of the big diameter surface. Since this composite polymer has much lower thermal conductivity and much lower thermal diffusivity than copper, please take into account that these IR measurements represent a temperature and temperature gradients significantly lower than those present on the inner (copper) surface of the big diameter flat end.
In my report I proposed that one way to eliminate thermal instabiltity of thin copper sheets is to use copper thick enough to eliminate a thermal instability.
Quoting my report:Quote from: Dr. J. RodalI have shown that a thermo-mechanical effect (thermal buckling of the base of the truncated cone) can account for some of the "anomalous" results reported by NASA's Brady et.al. I have shown that the buckling time is under 1 second for copper thicknesses under 0.84 mm (33 thousands of an inch) and just 2.6 watt power input. I have shown that the buckling temperature increase required is of the order of 1 deg C or less. I have shown that thermal buckling can produce a sudden output response.(Bold added for emphasis)
I have shown that the calculated buckling forces agree with the measured force (55.4 microNewtons). The buckling force is a very strong function of plate thickness (to the fourth power), to prevent thermal buckling from occurring it suffices to have a thicker copper sheet (1/8 inch or thicker would completely prevent this thermal buckling under these input powers).
This thermal buckling effect does not depend at all on air as a conducting medium; it will take place in a complete vacuum as well
Now that NASA is using a higher input power (50 watts) than in the Brady et.al. report, it appears that using a 1/4 inch thick (0.25 inches) copper plate for flat ends would prevent this thermal instability, and hence eliminate this artifact from consideration.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635194;image)
... Just as a note, we've already tried re-enforcing the frustum endplates with angle aluminum mounted on their outside surfaces and we didn't notice any marked change in its thrust response.This was expected not to make any significant difference.
...
Cotterell and Parkes (based on Cotterell's Ph.D. thesis at the University of Cambridge) correctly point out that the distribution of the heat flux "is not significant in the problem" of thermal buckling of a circular plate, whether the heating takes place uniformly over the whole circular plate or is concentrated in a central region. Cotterell chose a distribution with a heatedDiameterRatio =1/0.3=3.333 instead of the heatedDiameterRatio=1 analyzed by Noda et.al. The fact that the exact distribution is not significant for the deltaT that will produce buckling or for the buckling displacement follows from equilibrium: the membrane stress (=E*alpha*deltaT) force resultant (the integral of the membrane stress through the thickness) is reacted at the simply supported edges (that constrain the in-plane displacement). The membrane force resultant is uniform and it is equal in the polar radial and angular (azimuthal) directions. If only a central area is heated, the membrane stress is still equilibrated throughout. If the plate has uniform thickness and isotropic material properties, the strain in the non heated area prior to buckling is the same as in the heated area.
...measureable thrust was not observed when the PE or Teflon discs were removed from the copper frustum while in air with up to 30W of RF using our Mini-Circuit RF amp. ...
We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.
3) The effective way to remove thermal instability as an artifact is to get rid of the fiber-reinforced-epoxy boards at the flat ends and instead use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration
Not doing a test that would eliminate thermal instability as a variable because of...assuming that a "Tunnelling through" conjecture may also be eliminated?Quote3) The effective way to remove thermal instability as an artifact is to get rid of the fiber-reinforced-epoxy boards at the flat ends and instead use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration
No - Don't do that. Step back and look at the issue. We have a situation where we are reasonably certain (assuming a real effect) that something is either:
1 - Tunnelling through the copper end plates or,
2 - Going around the copper end plates, (via the QV).
In the first case, a quarter inch thick end plate would eliminate tunnelling and eliminate the thrust.
In the second case, who knows, except that logically a thick end plate would shield the thrust effect.
Of course the thick end plate would eliminate thermal effects but it would be a situation of "Throwing out the baby with the bath water."
I personally hold to the "Tunnelling through" concept via evanescent waves, to which point I intend to start posting information next.
As to why the vacuum test were observing less thrust than in air tests. please note the difference in the RF amps there were driving each test series. The 30W Mini-Circuit Class-A RF amp was used for the in-air series reported in the 2014 JPC paper, whereas a 100W EMPower Class-A/B RF amplifier was used in the vacuum tests to date. So how could a less powerful RF amp produce more thrust than a more powerful one?
... None of the above would make an Emdrive want to thrust and move through space, the final bit is what we uncovered in thread 1 concerning casimir forces with different geometries. We uncovered the casimir force is positive and repulsive inside spheres, corners and cones, unlike parallel plates where it is negative and attractive.
....
Substitute below copper 1, air 3, PE 2.
...Like they say on amazon, if you have been interested in this article, you might want to look at this one:
I accidentally stumbled upon this report:
https://hal.archives-ouvertes.fr/hal-00551421v1/document
Not doing a test that would eliminate thermal instability as a variable because of...assuming that a "Tunnelling through" conjecture may also be eliminated?Quote3) The effective way to remove thermal instability as an artifact is to get rid of the fiber-reinforced-epoxy boards at the flat ends and instead use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration
No - Don't do that. Step back and look at the issue. We have a situation where we are reasonably certain (assuming a real effect) that something is either:
1 - Tunnelling through the copper end plates or,
2 - Going around the copper end plates, (via the QV).
In the first case, a quarter inch thick end plate would eliminate tunnelling and eliminate the thrust.
In the second case, who knows, except that logically a thick end plate would shield the thrust effect.
Of course the thick end plate would eliminate thermal effects but it would be a situation of "Throwing out the baby with the bath water."
I personally hold to the "Tunnelling through" concept via evanescent waves, to which point I intend to start posting information next.
The R&D approach is to fearlessly perform many tests to eliminate possible artifacts and alternative explanations and to confirm and reproduce valid tests, not to conduct only a few tests that agree with an assumed theory.
...
I have attached a generated drawing of the cavity model used, showing placement of the
gaps. This is the placement for which the 0.25 mu-N/Watt force/power was detected,
though the gap, at 1.4 mm, is 10 times larger than actually used. That's to make it visible.
I'm not sure that I understand what you are asking for, but you may be interested in looking at the fields generated, both internal and external to the cavity. The first drawing shows a fully enclosed cavity, the second shows a cavity with gaps of 140 microns placed as illustrated in the previous drawing. Both cavities are driven by a magnetic source at the inside face of the dielectric disk, at 1.937115E+009 GHz. Also, both images are at the completion of the 32-nd half period of the drive frequency.
Look closely at the second image. Note the standing waves on both end plates and the RF energy looping from one end to the other, outside the cavity. And also, please read this paper, in particular page 15-16 but the complete paper is pertinent. http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf)
I'm not sure that I understand what you are asking for, but you may be interested in looking at the fields generated, both internal and external to the cavity. The first drawing shows a fully enclosed cavity, the second shows a cavity with gaps of 140 microns placed as illustrated in the previous drawing. Both cavities are driven by a magnetic source at the inside face of the dielectric disk, at 1.937115E+009 GHz. Also, both images are at the completion of the 32-nd half period of the drive frequency.
Look closely at the second image. Note the standing waves on both end plates and the RF energy looping from one end to the other, outside the cavity. And also, please read this paper, in particular page 15-16 but the complete paper is pertinent. http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf)
It looks to me that you have performed a similar analysis as Prof. Juan Yang in China and Fetta in the US, who solved Maxwell's equations in an EM Drive and also obtained resulting forces, because they did not model the EM Drive as a deformable body. They just solved Maxwell's equations and obtained a force from Maxwell's Stress Tensor.
It seems to me that you just used MEEP to solve Maxwell's equations. MEEP considers the EM Drive as a rigid body (you did not input the modulus of elasticity or thermal expansion coefficient or the electro- and magnetorestrictive material constants into the computer code). In the real world the EM Drive deforms due to the electromagnetic field.
This deformation of the EM Drive is quite real, it is because of this deformation that NASA Eagleworks (and others) have trouble keeping the EM Drive in resonance.
As a real body deforms when it is subject to an electromagnetic field you have to include electro- and magnetorestrictive forces in your analysis to model the real-world, in order to satisfy conservation of momentum. When one does that, the mechanical force on the center of mass of the EM Drive will turn out to be exactly zero, to satisfy conservation of momentum.
To properly do this, you would need a multi-physics computer code (to include the deformation of the EM Drive) like ANSYS, or COMSOL. (By the way my understanding of the COMSOL analysis done for NASA is that they included the COMSOL programs for Maxwell's equation and heat conduction, but that they did not (?) calculate the coupled deformation of the EM Drive either).
(http://www.comsol.com/model/image/366/big.png)
From a space flight application perspective what is the TRL of the EM Drive?
Here is the list:
TRL 1. Basic principles observed and reported
TRL 2. Technology concept and/or application formulated
TRL 3. Analytical & experimental critical function and/or characteristic proof-of-concept
TRL 4. Component and/or breadboard validation in laboratory environment
TRL 5. Component and/or breadboard validation in relevant environment
TRL 6. System/subsystem model or prototype demonstration in a relevant environment (ground or space)
TRL 7. System prototype demonstration in a space environment
TRL 8. Actual system completed and "Flight qualified" through test and demonstration (ground or space)
TRL 9. Actual system "Flight proven" through successful mission operations
I haven't seen enough experimental data to be able to say what TRL level the EM-Drive would have. The EM tether has been deployed in orbit so therefore it must have a TRL level of at least 7.
Edison started with a theory of how an electric light could be built that many thought was impossible. It was thought to be impossible not because the physics was believed to be wrong but because so many others had tried and failed.
Maybe of interest?
Some interesting tidbits how they did the modelling in the abstract...
http://link.springer.com/article/10.1140%2Fepjd%2Fe2014-50798-5
Full paper is paywalled however :(
.....
Oh, and just for clarity, I have measured the forces outside the fully enclosed cavity shown first above. The forces are identically zero for the fully enclosed cavity as has been proven mathematically time and again.
PS: I see a smiling face on that picture, with two eyes at the upper corners of the big diameter flat end of the EM Drive and a mouth at the bottom of the EM Drive :)I have looked through all of the 34 images generated, one each half period. There are several that stimulate the imagination.
Do the evanescent waves decay exponentially outside the EM Drive (as any evanescent wave should) ?
QuotePS: I see a smiling face on that picture, with two eyes at the upper corners of the big diameter flat end of the EM Drive and a mouth at the bottom of the EM Drive :)I have looked through all of the 34 images generated, one each half period. There are several that stimulate the imagination.QuoteDo the evanescent waves decay exponentially outside the EM Drive (as any evanescent wave should) ?
Yes, they do, or at least the forces do decay. Whether exponentially or by some other rule, they do decay.
I am suggesting that the EM thruster generates thrust force as follows:
1 - Electromagnetic energy departs the cavity via superluminal evanescent waves. See the paper that I quoted previously for justification of superluminal evanescent waves.
2 - The evanescent waves remain attached to the cavity (they do not propagate) and reach a maximum distance at which point they collapse and the energy returns to the cavity, either at the point of exit or some other attachment point. I think this is reasonably well accepted by theory.
3 - The evanescent waves, departing the cavity carried superluminal momentum which was reacted against the cavity. However, once the waves reach maximum distance and return to the cavity, there is no driving energy to cause them to return superluminally. Once the wave has fully collapsed, it has returned momentum p = m c, to the cavity, acting on the cavity.
It is the difference between p = m vsl reacting on the cavity, and p = m c acting on the cavity that results in a thrust force from the EM thruster.
This force is easy to calculate, it is p = m * ( vsl - c). What is harder to calculate is the value of vsl but the referenced paper gives formulas to calculate that value based on engineering parameters.
....Well (skipping the controversial subject of a superluminal speed vsl and the discussion in the referenced paper involving tachyons), just addressing the force, as you know p is the momentum, while the force is the rate at which momentum changes with respect to time (F = dp/dt) : therefore the average force would be given by that momentum change divided by the time interval in which that momentum change takes place.
This force is easy to calculate, it is p = m * ( vsl - c). What is harder to calculate is the value of vsl but the referenced paper gives formulas to calculate that value based on engineering parameters.
....Well (skipping the controversial subject of a superluminal speed vsl and the discussion in the referenced paper involving tachyons), just addressing the force, as you know p is the momentum, while the force is the rate at which momentum changes with respect to time (F = dp/dt) : therefore the average force would be given by that momentum change divided by the time interval in which that momentum change takes place.
This force is easy to calculate, it is p = m * ( vsl - c). What is harder to calculate is the value of vsl but the referenced paper gives formulas to calculate that value based on engineering parameters.
Can you please show results for force on the center of mass of the EM Drive and evanescent-wave images (showing the electromagnetic fields inside and outside the EM Drive) for the same case without the dielectric (for an empty cavity) ?
QuoteCan you please show results for force on the center of mass of the EM Drive and evanescent-wave images (showing the electromagnetic fields inside and outside the EM Drive) for the same case without the dielectric (for an empty cavity) ?
I can try. The run will take several hours and may not give useful images.
As you know from our discussions of a few days (weeks) ago, Harminv does not calculate resonant frequency very accurately. (I did get independent confirmation on that point.) So my best guess will be to use the same drive frequency as before?? That is what I used for yesterday's image but that data was from Paul March and seems to be pretty solid. In that case, Harminv calculated Q = O(1000) , much lower that Paul's data, but by looking at the images each half- period, the cavity looked to be in resonance. I don't know what I'll see without the dielectric and I am assuming you'd like to see results for a vacuum filled cavity? As opposed to air filled?
I'm pursuing a work-around to determine resonance without using Harminv, but I'm not there yet.
It will be a little while before I set-up and start the run so if you have further guidance, it might be helpful.
Edit: Just a further note, the difference between air filled and vacuum filled cavity is not really detectable from looking at the field patterns.
Quickly plugged in those measurements. Used TM212, geometric mean. Needed effective n=1.38 to get the freq w/ dielectric. Q is down to 1000 for 50mmN at 50W.
Quickly plugged in those measurements. Used TM212, geometric mean. Needed effective n=1.38 to get the freq w/ dielectric. Q is down to 1000 for 50mmN at 50W.
@ RODAL
Is that Q estimate from the last run (vacuum) relevant ?
That is what I used for yesterday's image but that data was from Paul March and seems to be pretty solid. In that case, Harminv calculated Q = O(1000) , much lower that Paul's data, but by looking at the images each half- period, the cavity looked to be in resonance.?
Quickly plugged in those measurements. Used TM212, geometric mean. Needed effective n=1.38 to get the freq w/ dielectric. Q is down to 1000 for 50mmN at 50W.
@ RODAL
Is that Q estimate from the last run (vacuum) relevant ?
That is what I used for yesterday's image but that data was from Paul March and seems to be pretty solid. In that case, Harminv calculated Q = O(1000) , much lower that Paul's data, but by looking at the images each half- period, the cavity looked to be in resonance.?
Actually, my concern is that the resonance frequency calculated by Harminv is as much as 3% off the peak.I'm not clear about the meaning of this. Please clarify:
Guys.
I'm reluctant to say this, but maybe some of the previous posts would be better of as PM's to each other?
I follow this thread avidly and I don't want to see it shut down again.
Maybe have a think?
I mentioned earlier that I had obtained independent confirmation of the Harminv discrepancy. Dr. Filip Dominic made some runs sampling the cylindrical resonator fields from meep, then analysed them using software independent of the meep package. He worked on it for about a week and determined that the Harminv values were off. They come closer as resolution is increased but my computer won't run this model at the high resolution needed to get closer.For a perfectly cylindrical resonator we have a simple exact solution (see: http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) all that one needs to do is to compare the frequency calculated by MEEP for a cylindrical cavity with the exact solution.
Dr. Dominic sent me the software that he developed to do the analysis and that is part of my work around so I hope to have confidence in the resonance frequency. The only real problem I have is that his software is in Python, a language that I will need to practice with before I can have any certainty.
Guys.
I'm reluctant to say this, but maybe some of the previous posts would be better of as PM's to each other?
I follow this thread avidly and I don't want to see it shut down again.
Maybe have a think?
I agree! But am worried about the thread. I'm sure Chris B will see it like yourself and I do...Guys.
I'm reluctant to say this, but maybe some of the previous posts would be better of as PM's to each other?
I follow this thread avidly and I don't want to see it shut down again.
Maybe have a think?
I'm not so sure that we shouldn't just let them go with this. The math has gone way beyond me now, but it's fascinating watching science evolve right in front of us.
When you combine what's being learned here with Dark Matter and Dark energy theory, it begins to look like there may actually be something to the old Ether Theory.
At least that's what it's starting to sound like.
...Great :)
@Rodal
In awe about the stuff discussed so far. I retract... It is good to hear you peeps discussing and arguing in the open.
Guys.
I'm reluctant to say this, but maybe some of the previous posts would be better of as PM's to each other?
I follow this thread avidly and I don't want to see it shut down again.
Maybe have a think?
I'm not so sure that we shouldn't just let them go with this. The math has gone way beyond me now, but it's fascinating watching science evolve right in front of us.
3 - The evanescent waves, departing the cavity carried superluminal momentum which was reacted against the cavity. However, once the waves reach maximum distance and return to the cavity, there is no driving energy to cause them to return superluminally. Once the wave has fully collapsed, it has returned momentum p = m c, to the cavity, acting on the cavity.
It is the difference between p = m vsl reacting on the cavity, and p = m c acting on the cavity that results in a thrust force from the EM thruster.
This old dog has to be dealt with. There isn't much left besides this:Agreed, all that NASA Eagleworks has to do to eliminate this artifact is:
Thermal instability technical paper from Rodal:
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1293349#msg1293349
I have a question about how the thrust is usually measured. Is it a pendulum? if so, could a physical cavity deformation simply move the barycenter? that could be mistaken as thrust.
Far from being an expert, I am still enjoying the thread :)
What I don't understand still is how that thermal buckling could appear as a sustained false thrust signature over 30-45 second runs, instead of just a quick impulse. Is it because the CG moved or something?Yes, good question. For a perfectly elastic pendulum it should restore itself, as you say. For it to persist for 45 seconds, one needs to posit some nonlinear non-conservative mechanism, perhaps in the nonlinear coupled equations of motion or perhaps also involving parasitic electromagnetic effects.
Could you share your Mathmatica code nevertheless?I have a question about how the thrust is usually measured. Is it a pendulum? if so, could a physical cavity deformation simply move the barycenter? that could be mistaken as thrust.
Far from being an expert, I am still enjoying the thread :)
It is a horizontal torsional pendulum, with the torsional axis of rotation in the vertical direction (call it "z"), paralel to the direction of the force of gravity and hence perpendicular to the floor. The EM Drive's force produces a rotation around that vertical axis "z", such that the motion of the EM Drive occurs mainly in the x-y plane parallel to the floor, perpendicular to "z". There is a small amount of coupling between the rotations around z, rotation around x and rotation around y due to the moments of inertia. I wrote a program in Mathematica taking into account the nonlinear coupled equations of motion, thinking that the forces could be an artifact due to nonlinear coupling of the equations of motion but I after comparing with the data I rejected that possibility.
This old dog has to be dealt with. There isn't much left besides this:Agreed, all that NASA Eagleworks has to do to eliminate this artifact is:
Thermal instability technical paper from Rodal:
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1293349#msg1293349
...get rid of the fiber-reinforced-polymer printed circuit board and just simply use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1329239#msg1329239
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1329424#msg1329424
For a perfectly cylindrical resonator we have a simple exact solution (see: http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) all that one needs to do is to compare the frequency calculated by MEEP for a cylindrical cavity with the exact solution.
Attached find the fields from the Copper Kettle at the 32-nd half-period of the drive frequency, 1.937115E+009 Hz. This would compare directly to the situation presented yesterday, except the dielectric has been removed.
I note that by watching the development of the fields from the first half-period, the cavity resonance does not seem to be as strong. That is, the fields drift with time. The strong blue point moves.
Attached find the fields from the Copper Kettle at the 32-nd half-period of the drive frequency, 1.937115E+009 Hz. This would compare directly to the situation presented yesterday, except the dielectric has been removed.
I note that by watching the development of the fields from the first half-period, the cavity resonance does not seem to be as strong. That is, the fields drift with time. The strong blue point moves.
You calculated a force with the dielectric in the cavity, what force do you calculate without the dielectric?
How does the force compare?
I accidentally stumbled upon this report:
https://hal.archives-ouvertes.fr/hal-00551421v1/document
I'm still trying to find which reference it was where any of this implied non-reciprocity.
Magneto-electric directional anisotropy can be induced in all media, including centrosymmetric
ones. It was first predicted by G. E. Stedman and coworkers [11] and observed for the first time in
a crystal by G. L. J. A. Rikken and coworkers [12]. This non-reciprocal effect is supposed to be independent on light polarization.
I accidentally stumbled upon this report:
https://hal.archives-ouvertes.fr/hal-00551421v1/document
I'm still trying to find which reference it was where any of this implied non-reciprocity.
It does imply non-reciprocity:
http://arxiv.org/pdf/1101.1174v1.pdf
Section 2.1.QuoteMagneto-electric directional anisotropy can be induced in all media, including centrosymmetric
ones. It was first predicted by G. E. Stedman and coworkers [11] and observed for the first time in
a crystal by G. L. J. A. Rikken and coworkers [12]. This non-reciprocal effect is supposed to be independent on light polarization.
I'm sure any optics expert would tell me, well duh!
Attached find the fields from the Copper Kettle at the 32-nd half-period of the drive frequency, 2.168E+009Hz. In this case, dielectric has been removed and the drive frequency has been increased. Increased drive frequency means that the actual simulated time is less than in the previous cases because the period is shorter.Thanks. It appears then that the evanescent fields are strong and unsymmetric (fore and aft of the EM Drive) with a resonant cavity with the dielectric at 1.9 GHz
Is there anything useful right now, today..... that can be done with an always on 50uN of thrust in space?Why limit oneself to just one EM Drive engine in space?. How about posing the question as:
IIRC, the ISS has 30KWe extra to play with.Is there anything useful right now, today..... that can be done with an always on 50uN of thrust in space?Why limit oneself to just one EM Drive engine in space?. How about posing the question as:
Is there anything useful right now, today..... that can be done with an always on N*50uN of thrust in space where N is an integer multiple (1,2,3,4,...) of 50 watts per engine.
For example, 4 engines: total thrust 100uN at total power 200 Watts, 10 engines 500 uN at 500 Watts total.
IIRC, the ISS has 30KWe extra to play with.Is there anything useful right now, today..... that can be done with an always on 50uN of thrust in space?Why limit oneself to just one EM Drive engine in space?. How about posing the question as:
Is there anything useful right now, today..... that can be done with an always on N*50uN of thrust in space where N is an integer multiple (1,2,3,4,...) of 50 watts per engine.
For example, 4 engines: total thrust 200uN at total power 200 Watts, 10 engines 500 uN at 500 Watts total.
2) It would be great to get the forces on the center of mass of the EM Drive you compute for the three different cases
IIRC, the ISS has 30KWe extra to play with.Is there anything useful right now, today..... that can be done with an always on 50uN of thrust in space?Why limit oneself to just one EM Drive engine in space?. How about posing the question as:
Is there anything useful right now, today..... that can be done with an always on N*50uN of thrust in space where N is an integer multiple (1,2,3,4,...) of 50 watts per engine.
For example, 4 engines: total thrust 200uN at total power 200 Watts, 10 engines 500 uN at 500 Watts total.
That's 600 EM Drives giving 0.03 Newtons total thrust :)
They need to increase the Thrust/Power to decrease the number of EM Drives necessary.
So blue is the most negative and red is the most positive in that scale.Quote1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?
Attached is the best I can do on short notice. I've looked at the available color palates in HDFView and they are weak, to say the least. Or maybe I just don't know how to scale them. I would like to know paraview better because I think it could display the data and in the format you wanted. Lines of constant value would be good. iso - whatevers.
1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?
What is white ? What is black?
White may be the most positive (off-scale) and black the most negative (off-scale), but I would like you to confirm...
... Just as a note, we've already tried re-enforcing the frustum endplates with angle aluminum mounted on their outside surfaces and we didn't notice any marked change in its thrust response.This was expected not to make any significant difference.
...
As I wrote in my report:Quote from: Dr. J. RodalCotterell and Parkes (based on Cotterell's Ph.D. thesis at the University of Cambridge) correctly point out that the distribution of the heat flux "is not significant in the problem" of thermal buckling of a circular plate, whether the heating takes place uniformly over the whole circular plate or is concentrated in a central region. Cotterell chose a distribution with a heatedDiameterRatio =1/0.3=3.333 instead of the heatedDiameterRatio=1 analyzed by Noda et.al. The fact that the exact distribution is not significant for the deltaT that will produce buckling or for the buckling displacement follows from equilibrium: the membrane stress (=E*alpha*deltaT) force resultant (the integral of the membrane stress through the thickness) is reacted at the simply supported edges (that constrain the in-plane displacement). The membrane force resultant is uniform and it is equal in the polar radial and angular (azimuthal) directions. If only a central area is heated, the membrane stress is still equilibrated throughout. If the plate has uniform thickness and isotropic material properties, the strain in the non heated area prior to buckling is the same as in the heated area.
See:
Cotterell, B., and Parkes, E. W., Thermal Buckling of Circular Plates, (United Kingdom's) Aeronautical Research Council, Ministry Of Aviation, Reports and Memoranda No. 3245, September, 1960
QUESTION: Why did you use a glass-fiber-reinforced polymer printed circuit board as the end plate ? << 0.063 inch thick FR4 printed circuit board with 1.0 oz copper, (~35 microns thick of Cu epoxied to the FR4 fiberglass)>>
1) The IR measurement was done from the outside, with the IR camera looking at the composite polymer surface of the circuit board surface they had on the exterior of the big diameter flat end. Since this composite polymer has much lower thermal conductivity and much lower thermal diffusivity than copper, please take into account that these IR measurements represent a temperature and temperature gradients significantly lower than those present on the inner (copper) surface of the big diameter flat end. In other words, the composite polymer circuit board surface being measured with the IR camera acts like an insulating surface concealing the higher temperature of the inner copper surface. Moreover, due to very low thermal diffusivity of the glass-fiber-reinforced polymer printed circuit board, measurement of its exterior surface presents a considerable time delay of the interior temperature vs. time profile (as it takes time for the heat to conduct through the thickness of the very low diffusivity of the glass-fiber-reinforced polymer printed circuit board).
2) The modulus of elasticity of the glass-fiber-reinforced polymer printed circuit board is much lower than the modulus of elasticity of the copper. The glass-fiber-reinforced polymer printed circuit board has orders of magnitude lower thermal conductivity and thermal diffusivity than the copper. (Comparison noted below).
3) Why not get rid of the fiber-reinforced-polymer printed circuit board and just simply use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration ?
As to your questions, I would need some time to give them the analytical consideration they deserve and to calculate, rather than give you an impulsive, reflexive, answer that may be incorrect.
NOTE: FR-4 is a composite material made with woven fiberglass cloth embedded in an epoxy resin (polymer) matrix. The in-plane Young's modulus of FR4 is 3.0×10^6 psi , about six times smaller than Copper's Young modulus of 17.0×10^6 psi. The modulus of elasticity in the thickness direction is much lower, practically as low as the modulus of elasticity of epoxy. FR4's coefficient of thermal expansion - x-axis 1.4×10^(−5) 1/K, Coefficient of thermal expansion - z-axis 7.0×10^(−5) 1/K
The thermal conductivity is a tiny 0.29 W/m·K in the thickness direction, due to the low thermal conductivity of the epoxy resin. Copper has a thermal conductivity of 401 W/m·K, that is 1400 times higher than the thermal conductivity of FR4
...the large OD end of the Eagleworks copper frustum, the mass of the entire frustum assembly without the PE discs is listed as 1.606 kg. Your 0.25" thick solid copper end plates would add over 3.0 kg of dead mass to this figure just for the small and large OD ends plates and cost us $333.50 for a 12"x 24"x0.25" copper plate stock from McMaster-Carr needed to make them.
we have tried aluminum angles and even 0.090" thick AL plates across the existing PCB end caps and noticed no change in its performance except for the increase in seismic noise pickup that the extra mass such payload-mass increasing modifications always bring to the table.
We are on the edge of a golden age of spaceflight with EM drives and superconducting capacitors. Or maybe not, but at least it is fun to discuss it. :)
Quote1) You need to give us a contour field mapping rule: what do the colors mean in numerical terms, to further understand the contourplot. For example: what is the intensity of the white areas? of the red areas? of the orange areas? of the blue areas?
Attached is the best I can do on short notice. I've looked at the available color palates in HDFView and they are weak, to say the least. Or maybe I just don't know how to scale them. I would like to know paraview better because I think it could display the data and in the format you wanted. Lines of constant value would be good. iso - whatevers.
Hopefully this will be more usableQuoteWhat is white ? What is black?
White may be the most positive (off-scale) and black the most negative (off-scale), but I would like you to confirm...
I don't know the answer to your question but I think that your guess is right. I know that the black boarders of the cavity are perfect metal which is confusing as it is not field strength. But the colors are not single valued. The palates seem to be designed for "Pretty" and not for information. There are two single valued palates in hdfview, both gray and both wash out the differences in field strength. The h5topng color palates also wash out the color, and don't even show the evanescent waves. So I'm not using that program. Again, I need to explore paraview's capabilities.
If it were easy, everyone would do it, no?
What I need is more hands and more skills, more skills for sure.I was suggesting you to look at a few values, if you had the time and if you were interested on what those contours mean. Otherwise I understand :)
I tried to attach the digital output source of the final fields for the copper kettle as designed. It is only 125.4 MB, I would like to share the much more interesting file showing the evolution of the fields from start-up, but it is 4.4 GB so it might not be something Chris would want me to do. Actually, Chris doesn't want people uploading .h5 files at all. I discovered after waiting through the complete upload that .h5 is not an allowed format.
Aero,
From what I am reading you keep mentioning "superluminal velocity proposition of evanescent waves". Would I be correct in assuming that you are talking about the apparent velocity of teh wavform themselves and not the matter or energy that the waveforms themselves are composed of?
Otherwise, this put's a whole new slant on this EM drive debate.
Aero,
From what I am reading you keep mentioning "superluminal velocity proposition of evanescent waves". Would I be correct in assuming that you are talking about the apparent velocity of teh wavform themselves and not the matter or energy that the waveforms themselves are composed of?
Otherwise, this put's a whole new slant on this EM drive debate.
I'm referring to superluminal velocity as presented here http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf)
I need an interpretation from someone more knowledgeable than I, in order to know exactly what it is that I'm talking about. Perhaps you can tell me?
.....Interesting find. The paper concludes with this advice:
*** http://arxiv.org/pdf/1411.5359v1.pdf (the QVPT model has officially "got served")
Although the extraction of a net momentum has been postulated in inhomogeneous vacuums [35] (due to a different mechanism than that discussed in this paper), the effect was found to immeasurably small, and it remains unclear whether this small non-zero value is an artefact of the field regularization techniques used.Regardless though, if a continuous net force is indeed being produced in the experiments in Refs. [38–41], one might expect that this should also imply an anomalously high power loss from the electric circuits of the thruster device. This power loss would be in addition to any standard power losses associated with such things as: ohmic heating, eddy current losses, dielectric and ferrite heating, radiation losses, etc. Consequently, a dedicated effort to isolate known power losses from the total input power of the device should identify any additional anomalous losses.
Rodal:
QUESTION: Why did you use a glass-fiber-reinforced polymer printed circuit board as the end plate ? << 0.063 inch thick FR4 printed circuit board with 1.0 oz copper, (~35 microns thick of Cu epoxied to the FR4 fiberglass)>>
3) Why not get rid of the fiber-reinforced-polymer printed circuit board and just simply use a 1/4 inch thick (0.25 inches) copper plate for flat ends to prevent this thermal instability, and hence eliminate this artifact from consideration ?
Answer: I used the FR4 PCB with 1.0oz copper end-plates to minimize payload mass while maximizing the thrust to weight ratio of the copper frustum assembly AND the signal to noise ratio of the torque pendulum system. I used the 1.0oz copper thickness because the ac skin depth of RF at 1.5 GHz is about 2.0 microns, so 5X that depth or 10 microns of copper should contain 99% of the ac currents at this frequency. And I still had an additional 25 microns of copper thickness as non-current carrying thermal mass to stabilize its performance.
Now if you care to look at my pictures of the large OD end of the Eagleworks copper frustum, the mass of the entire frustum assembly without the PE discs is listed as 1.606 kg. Your 0.25" thick solid copper end plates would add over 3.0 kg of dead mass to this figure just for the small and large OD ends plates and cost us $333.50 for a 12"x 24"x0.25" copper plate stock from McMaster-Carr needed to make them. As I've said before we have tried aluminum angles and even 0.090" thick AL plates across the existing PCB end caps and noticed no change in its performance except for the increase in seismic noise pickup that the extra mass such payload-mass increasing modifications always bring to the table.
Best, Paul M.
This is an op ed.
Putting this all in perspective, the successful measurement of a thrust signature in hard vacuum helped me gain real confidence that the Emdrive and Cannae* are in fact producing a real thrust signature which begs explanation. For now it appears to work, but barely. Not enough to make people take notice, even though it works >6000x better than a photon rocket. This has potential to be HUGE. It would be irresponsible to not take this seriously now. Yes this is high risk, but it is also very high reward. I've been reading about crowdsourcing science lately after hearing a piece about it on the SGU podcast. Wouldn't it be nice if we could crowdsource research into the Emdrive.
I'm thinking crowdsourcing because there is a taboo associated with this subject. Because it is assumed to go against established scientific concepts. Academic institutions and professionals would no doubt be hesitant to publicly acknowledge involvement in such research, without sufficient evidence this is real. Put another way, they won't touch it until someone before them assumes the risk first. BZ to Eagleworks for having the courage to at least take a look. This is the public attitude, but if you really examine the literature, Emdrive can be explained via established principles and only serves as experimental evidence supporting the quantum foundations of reality.
As I've said, this isn't just some neat thruster, if it works it is also an instrument which could give immense insight into the nature of space and time itself. We really need contributions from experts in optics, materials science and QFT, with open minds. If we go the crowdsource route, we need a platform and we need leadership. Just like the hyperloop. This problem is to be figured out or put to rest. I have confidence that Eagleworks can eventually figure this out, but at the same time, we need to provide forceful backup**. The last thing we need is for this potential world changing technology to fall prey to an unworkable theory which leads to no results and time running out***. I know this sounds harsh, and I mean no disrespect. Do we want to be famous or correct? Both have to be true, to be true. In this writer's opinion, this is exactly what happened to ME. The inability or unwillingness to adapt one's theory in the face of new information and scrutiny. Can you imagine the space flight applications that could come from this potential technology, if it is in fact a reality and we can figure it out? Can you imagine what could have happened if we had not let it slip through the cracks for several more years? We (humanity) need to slough off our scientific hubris. We don't know everything yet; we only think we do. Quoting the controversial Rupert Sheldrake, "The science delusion is the belief that science already understands the nature of reality in principle, leaving only the details to be filled in. This is a very widespread belief in our society........." He is pointing out our hubris, how we think we know it all already, even as we are such a young, immature species. We don't know jack. Our collective ego surpasses our wisdom. The insight to be gained from our universe is as infinite as the universe itself, our comprehension is unfortunately finite.
http://www.nbcnews.com/tech/innovation/hyperloop-may-become-crowdsourced-reality-within-decade-n272116
http://www.usatoday.com/story/news/nation/2014/07/25/ozy-crowdsourcing-science/13143465/
http://www.nextscientist.com/3-examples-crowdsourcing-science/
http://www.abc.net.au/news/2014-09-10/crowd-sourced-research-more-trouble-than-it-is-worth-study/5734444
*We need to analyze Emdrive and Cannae equally; eg does thermal instability hold for both?
**Naval leadership concept
*** http://arxiv.org/pdf/1411.5359v1.pdf (the QVPT model has officially "got served")
Dr. McCulloch has derived a new expression taking into account the three-dimensional nature of the truncated cone EM Drive and constructed a new comparison table.
P=Power Input
Q=Quality Factor of Resonance
c=speed of light
wb=Big Diameter
wc=Small Diameter
L=Length
The McCulloch thrust (F), was (2-D expression)
F = PQL/c * (1/wb - 1/ws) (1)
and it is now (3-D expression)
F = 6PQL/c * ( 1/(L+4wb) - 1/(L+4ws) ) (2)
See
http://physicsfromtheedge.blogspot.com/2015/02/mihsc-vs-emdrive-data-3d.html
(http://2.bp.blogspot.com/-Dnqt3RKcybk/VN4zCFC2JqI/AAAAAAAAAEs/kW12ut-78cc/s1600/DatavsMiHsC3.jpg)
Has anyone here considered a kickstarter campaign?
...
Do we have a complete set of data like Mike's table, including mode numbers ?
I've been reading this thread with great interest, and thank you all for all the information you brought. (i've learnt a bunch of things and been happy to read back my physics courses again)
BUT: I don't understand why the simplest explanation here:
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1293349#msg1293349
NASA'S MICROWAVE PROPELLANT-LESS THRUSTER ANOMALOUS RESULTS:
CONSIDERATION OF A THERMO-MECHANICAL EFFECT
wouldn't explain all the results obtained so far (in ambiant air pressure and in a lab's vacuum)
Is there a need to find other complicated explanations before this one is proven wrong ?
Either this : sharp stop of displacement at power-off, sharp thrust opposite to initial direction.
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Or this : gentle stop of displacement at power-off, harder to see but implies higher total integrated displacement (many centimetres)
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While what is observed looks like a net imbalance (more above the baseline than below)
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I've been reading this thread with great interest, and thank you all for all the information you brought. (i've learnt a bunch of things and been happy to read back my physics courses again)
BUT: I don't understand why the simplest explanation here:
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1293349#msg1293349
NASA'S MICROWAVE PROPELLANT-LESS THRUSTER ANOMALOUS RESULTS:
CONSIDERATION OF A THERMO-MECHANICAL EFFECT
wouldn't explain all the results obtained so far (in ambiant air pressure and in a lab's vacuum)
Is there a need to find other complicated explanations before this one is proven wrong ?
From what I understand (Rodal please correct me if wrong as I may have skimmed that too fast) the thermal buckling can very well explain the initial steep step thrust response to power-on. The steepness of the initial measured thrust on power-on were used as an argument by Eagleworks to rule out any thermal effect (as any thermal effect was supposed too slow to explain the sharp rise). Rodal's work shows that a thermal effect is not ruled out as far as initial steep rise is concerned : thermal buckling can account for the magnitude and rate of the initial rise (same ballpark).
The question remaining is the sustained level of apparent thrust after the rise, sustained for 35 or 40 s at approx. constant magnitude. I'm not sure this was tackled and ruled out as possibly being produced by pure thermal buckling/dilatation explanation but my feeling (shared ?) is that it is hardly possible. A constant thrust of 50µN for 40s means a mass of 1kg (out of my hat, ballpark of heated mass) accelerating at constant a=F/m=50e-6 m/s² during the thrust plateau of 40s, that is an integrated displacement of (some mass of 1kg relative to rest of the frustum + balance arm) x=0.5 a t² = 4 cm (more than an inch).
Also to have a (more or less) nice fall to flat baseline at power-off (as observed) would mean this moving mass would stop accelerating but continue at its gained velocity (relative to rest of frustum + balance arm) and ideally stop very gently, at opposite acceleration with magnitude much lower than the previous one. This continuation of movement would add even more to the total displacement, I'd say a few times 4cm (like 10 or 20 cm...). Otherwise if the moving mass where to stop quickly at power-off, we would observe a sharp fall of the thrust signature much below the initial 0 baseline. Generally you could tell such "thrust from displacement of one part of the drive relative to another part of drive (1)" by seeing a 0 net thrust when integrating during the power-on and well after the power-off : you would see a part above the baseline (power-on period) and a part below (after power-off) and the later would cancel the former.
Either this : sharp stop of displacement at power-off, sharp thrust opposite to initial direction.
-----
| |
...------- | --------...
| ---
| --
-
Or this : gentle stop of displacement at power-off, harder to see but implies higher total integrated displacement (many centimetres)
-----
| |
...------- | ----...
----------
While what is observed looks like a net imbalance (more above the baseline than below)
-----
| |
...------- --------------...
It would certainly be possible to hide a moving mass inside the frustum, with a system to make it move the right displacement (many cm) to mimic a thrust signature with apparent net imbalance as seen from the outside (for not too long after power-off and with a "drifting baseline" to blur the opposite thrust period), but it's hard to see how such a huge displacement could happen by accident or stay unnoticed by experimenters.
I would say that a thermo-mechanical effect involving a simple linear displacement of some driver's part mass is rather well ruled-out as an explanation for the sustained part (40 s) and early after decay of the signal. Maybe some more complex classical explanation might still apply.
(1) by "drive" I consider the whole system mounted on the balance's arm and the arm itself
Rodal & Crew.
There is a major problem with your explanations of the copper frustum's "thrust" traces being strictly due to the frustum's large OD end-cap's immediate inward oil-canning to the left, see attached thermal expansion diagram, which is then followed by the copper frustum's longer-term thermal expansion to the left of its 0.024" thick copper cone material. And this problem is that these thermal effect explanations for the generated torque pendulum (T.P.) movements are in the wrong direction to account for the observed thrust traces. I.e., they are fighting the observed thrust traces, not adding to or creating them.
Now Newton's third law still states that for every action there is an equal and opposite reaction. So when the copper frustum's large OD end-cap's prompt and inward oil canning action, followed by the slower frustum cone thermal expansions, they both push the copper frustum's Center of Mass (CoM) to the left as viewed from the front of the Eagleworks' vacuum chamber looking back at the test article and torque pendulum, while noting how the copper frustum is bolted on to the T.P.. These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
However the observed up-going in the Y-axis thrust traces, see attached 50W slide, require the T.P. to move to the left, whereas the thermal expansion induced left-going CoM actions require the T.P. to move to the right, which should REDUCE and modify over time the magnitude of the observed thrust signal coming from the copper frustum actions of accelerating QV plasma to the right and out of the frustum. And you can see this negative longer term frustum thermal drift by noting the downward going baseline slope of the thrust trace even after the RF power is removed from the copper frustum.
Best, Paul M.
@Rodal -I would appreciate getting an answer directly from Paul March to both of the following questions, (even if you think that it has already been answered with a diagram) as follows:
Its easy to overlook items when there is a lot of new data to evaluate, but Thrust is to the left. See attached.
What about Cannae? It has completely different construction. Thrust was measured from it too. How does buckling explain Cannae? ...Where are the dimensions, and materials, of the Cannae device tested at NASA Eagleworks so that this question can be answered numerically ?
We have Cannae dimensions. Page 6 of the anomalous thrust paper has some.How can one can conduct a thermal instability calculation with this information ?:
Each Cannae test article is approximately 11 inches in diameter and 4-5 inches between the ends of the beam pipes, not counting beam pipe extensions or antenna mounts.
https://www.youtube.com/watch?v=57q3_aRiUXs
From the video that Shawyer made of his test configuration , many years ago, it is clear that the cone is moving towards the small diameter.
Not sure to why he wanted to represent his findings in a drawing that resembles a rocket engine (action- reaction) where there clearly is no exhaust force.. it kinda puzzles me...
Let's hope Paul March gives a conclusive answer to that so we can leave that confusion behind us.
Btw, ever since the EMdrive got worldwide publicity, a few months ago, I've been trying to follow the different discussions pro and contra between "believers" and "non-believers". I find the discussions here, on the NASA forum, by far the most constructive discussion.
Having only a basic scientific background, it is indeed sometimes tough to follow the discussions between professionals when they venture into the higher levels of mathematics, radiation physics and quantum mechanics, but even with only a 50% understanding it is great to see things unfold.
Strangely enough it gives me the same degree of excitement, then when I watched the live feed on the discovery confirmation of the Higgs-boson. Maybe, just maybe, we are indeed on the edge of a new chapter in space exploration...
Fantastic what you people established here. Really!
It is inspiring to see the collaboration from different fields in action, almost in real time...
Not sure, but if I may do a prudent suggestion, but in the discussion about magnetic permeability (some pages ago), wouldn't it make more economical sense to use iron instead of metglas. I believe it would be far easier to shape a slab of iron then finding a plate metglas 2714a. On condition iron scales linear compared to metglas, an iron backplate would still perform roughy 10 times better then copper.
Enough to validate all discussions till now for a reasonable price... ?
Geert
Do we know what the Eagleworks vacuum chamber is made of? I think I remember it being a Stainless Steel chamber but I can't find confirmation of that at the moment. It is kind of important to me because the evanescent fields from my simulation runs overlap the edges of the vacuum chamber. That means to me, that I need to add the vacuum chamber to my meep model. And expect different answers as a result.That's an excellent question, @aero, thanks for bringing it up. I agree with your reason for asking it.
Hello;
I have been following this for a while, but this is my first post. (I have corresponded with José Rodal about this in the past.) My congratulations on a spirited and informative discussion of some thorny issues.
It is apparent that the E&M waves on the outside of the drive extend far enough to interact with the walls of the vacuum chamber (not to mention the support, pendulum and other mechanisms inside the chamber). Thus, to verify (or rule out) the reality of the measured thrust, it will be crucial to calculate the force caused by these interactions. As I was reading through the forum, this point impressed itself upon me, and I was going to ask if it has been done but, of course, if we don't know the material of the chamber, it hasn't.
MEEP should be adequate to do this, as this is entirely a conventional physics effect, and I would encourage someone to take this on.
All:
Sorry I didn't make the time to participate in this ME-Drive forum for the last 6-to-8 months up, but I will try to catch up with everyone else in due course. That said lets try to answer the questions that popped up since my morning post.
1. I was not the lead author for the Eagleworks' 2014 AIAA/JPC paper and in fact I only supplied pictures and data for same during that period because Dr. White thought that my time was best spent in the lab gathering data instead of report writing. Thus some of the details that Dr. Rodal is looking for may have been lost or garbled in the report writing by the others on the author list.
2.0 The thrust vector for the four resonant modes examined in detail, (the cavity's fundamental TM010, TE012, TM211 & TM212 for our copper frustum is normally in the frustum's large OD to small OD direction for most, but not all the E&M resonant modes checked. However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map. Sorry, but a one size fits all solution to this EM-Drive thrust direction is not available in this venue because of the importance of the ExB phase relationship of the expressed Lorentz forces between the excited E&M fields and the possible dielectric and QV plasma flow phenomenon that may be at work in each resonant mode expressed. That is why this type of E&M thruster is so hard to get a handle on, for there are far too many degrees of freedom in the system to track let alone directly control.
3. The Eagleworks vacuum chamber's main body is made from 304L stainless steel while its swing out door is made from aluminum. Most of the nuts and bolts in the vacuum chamber are also made from 18-8, 304 or 316 stainless steel alloys.
Now to try to answer Dr. Rodal's specific questions:
"1) In the NASA experiments the truncated cone's center of mass moved towards the [ ? ] diameter end (where ? stands for big or small)"
For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum.
"2) In the NASA experiments, we at NASA Eagleworks define the thrust force direction to be in the [? ] direction as the movement of the truncated cone's center of mass (where ? stands for same or opposite)"
For just the TE012 & TM212 excited resonant modes, the thrust force direction AKA thrust vector was observed to be in the same direction as the movement of the frustum's center of mass when RF power was applied to the frustum's magnetic loop antenna.
If I missed a question along the way keep asking, but I'll be in and out of the house for the rest of the day, so I may not get to answer them until late this evening or tomorrow afternoon USA based CST.
Best, Paul M.
....@aero had this question,
If I missed a question along the way keep asking, but I'll be in and out of the house for the rest of the day, so I may not get to answer them until late this evening or tomorrow afternoon USA based CST.
...
please look at this model and tell me if your read of Paul March's description of the cavity joins are as shown, or is there a cone flange pinched under the Teflon gasket which is held in place by a thicker copper ring.
The fact that it has reverse too pretty much clinches it. That speaks volumes.You are right that "it speaks volumes", I agree, the good news about the EM Drive just keeps on coming from Eagleworks. but before "clinching it" we still have to address the electromagnetic field interaction, e.g. evanescent wave interaction with the vacuum chamber and other fixed components, as the ExB field phase relationship changes, don't we ?
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQaH7F0WjOYKzk6tzWMguQUCEVZ8XBeBNg0F_kpNmYfvMmQIbZluwUzt4k)
(https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSqY-ef16FoCA8if0gj8HzYI0wwOQ4NTT5R2Be-0gxw6QlhuM03EEKil7A_PA)
I'm thinking an xU cubesat with a big battery. Spin stabilized even at 50 micro newtons we would see positive results within an hour, tracked from the ground.I hoped to be experimental about this.
I'm thinking an xU cubesat with a big battery. Spin stabilized even at 50 micro newtons we would see positive results within an hour, tracked from the ground.I hoped to be experimental about this.
Experiment trumps theory every time.
With what we have, lets have an experiment in zero-g
http://cannae.com/2-uncategorised/48-cubesatI'm thinking an xU cubesat with a big battery. Spin stabilized even at 50 micro newtons we would see positive results within an hour, tracked from the ground.I hoped to be experimental about this.
Experiment trumps theory every time.
With what we have, lets have an experiment in zero-g
Someone have a word with Elon.... He must know a thing or two... The Cannae stuff seems like a scam...
Cool. Elon should be all over this then...Probably not while it's still this early in TRL. There's not much to lose in waiting for what seem to be imminent new empirical data.
Given that thrust follows the dielectric and can be controlled at will; it is clear that this is no artifact.
Elon should employ Rodal, Mullertron, NotSureOfIt et al to examine anomalous thrust.
To not do so would be bad business.
@elonmusk
If u saw @TheSimpsons and wonder why @SpaceX doesn't use an electric rocket to reach orbit, it is cuz that is impossible
The fact that it has reverse too pretty much clinches it. That speaks volumes.
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQaH7F0WjOYKzk6tzWMguQUCEVZ8XBeBNg0F_kpNmYfvMmQIbZluwUzt4k)
(https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSqY-ef16FoCA8if0gj8HzYI0wwOQ4NTT5R2Be-0gxw6QlhuM03EEKil7A_PA)
Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
I agree with Mulletron that the answer to Paul March's question is that it is much more effective to have a distributed power spectral density than the power concentrated at a single frequency spike. When the natural frequency changes in an unpredictable manner, it is much more effective to have a distributed power spectral density of excitation (it is the power spectral density ( http://en.wikipedia.org/wiki/Spectral_density#Power_spectral_density ) over the spectrum of changing natural frequencies that matters).Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
...
the resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively
Prior to the TM211 evaluations, COMSOL® analysis indicated that the TE012 was an effective thrust generation mode for the tapered cavity thruster being evaluated, so this mode was explored early in the evaluation process. Figure 22 shows a test run at the TE012 mode with an operating frequency of 1880.4 MHz. The measured quality factor was ~22,000, with a COMSOL prediction of 21,817. The measured power applied to the test article was measured to be 2.6 watts, and the (net) measured thrust was 55.4 micronewtons. With an input power of 2.6 watts, correcting for the quality factor, the predicted thrust is 50 micronewtons. However, since the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.
Abstract
A microwave resonator system is made, which has a tapered resonant cavity, a microwave source, and a transmission device. Because of the electromagnetic pressure gradient on the tapered resonant cavity, a net electromagnetic force along the axis of the cavity may be observed, which is needed to verify experimentally the use of the independent microwave resonator system. It is also needed to keep the independent microwave resonator system in resonating state, which is the important procedure to demonstrate the possibility of net electromagnetic force. Thus, a low-signal resonating experiment on the tapered resonant cavity combined with resonating parts is completed to accurately find out the resonant frequency of 2.45 GHz and to analyze the influence of temperature on the resonant state. Experimental result shows that the resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively. When the temperature of the tapered resonant cavity wall rises, the resonant frequency will be decreased and the quality factor changed separately.
"the electromagnetic field intensity calculated in the vicinity of the axis is larger, therefore the center of the small end has a higher thermal energy, thus heating quickly,"
....
"we measured the cavity surface surface temperature at different locations as shown in Figure 11 with a thermocouple. [Fig. 11, which I attach below shows the positions of the thermocouples noted as "1" to "6"] Temperature measurements at different points vs. time, are shown in FIG 12 [Fig 12 which I attach below shows the temperature vs time at the 6 different thermocouple locations]. The temperature at the center of small end [thermocouple #1] first began rising rapidly."
@Paul March,
It is kind of important to my results if you could confirm that the Teflon Rubber gaskets are installed as illustrated in the attached model. Click on the image, it will expand so you can see detail - but of course it is mostly black so use the sliders to move around to find a corner. :)
Right now, I am using a 12.5 mm coaxial dipole antenna at the inner face of the dielectric disk. I know you used a loop of some sort. How much do you think this difference matters considering that I am running a digital model?
It is also important that I correctly model the width of the Teflon Rubber gasket filled gap. You wrote that the gasket was .064." Was that after installed, or did you compress it when you tightened down the retaining ring. If so, what would you estimate the actual distance is, between the copper cone and copper base plate, as installed? I know that sounds like a nonsense question, but my simulation shows thrust force is dramatically sensitive to just a small changes in the gap width. I'd like for my model to be as close as is possible to your Copper Kettle thruster.
My final question (I hope) re. the gasket is, "Do you know what the dielectric constant is for the actual Teflon Rubber that you used?" (Did your supplier document it, perhaps.) I find values ranging from 2.1 to 2.5 and while force is not very sensitive to this value, it does have an effect.
And while I'm at it, I read that the vacuum chamber is 30 inches by 36 inches, diameter by length. Is that inside or outside dimensions?
I agree with Mulletron that the answer to Paul March's question is that it is much more effective to have a distributed power spectral density than the power concentrated at a single frequency spike. When the natural frequency changes in an unpredictable manner, it is much more effective to have a distributed power spectral density of excitation (it is the power spectral density ( http://en.wikipedia.org/wiki/Spectral_density#Power_spectral_density ) over the spectrum of changing natural frequencies that matters).Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
...
The reason for this is that (as has been verified by Prof. Juan Yang in China by inserting thermocouples at different places in the EM Drive) the EM Drive is subjected to a very non-uniform temperature distribution, with the temperature increasing with time, that results in significant non-uniform thermal expansion of the EM Drive, and therefore the natural frequencies must shift with temperature (and therefore shift with time as the temperature changes with time) as the EM Drive expands non-uniformly with time. Therefore, having the power concentrated at a single frequency spike (NASA) is bound to be non-efficient as the resonant frequency changes with time, the EM Drive is going to move out of resonance even if one happens to excite it at the correct frequency to start with. The COMSOL calculations do not provide the natural frequency to enough precision within the extremely narrow bandwidth of a high Q resonance (the higher the Q, the narrower the resonant bandwidth) for NASA to know exactly the natural frequency for a given mode shape. More importantly, the COMSOL calculations do not provide the information needed for NASA to know how to shift the frequency with time, as the EM Drive thermally expands non-uniformly to stay at peak resonance.
This is evident from the very low Q's reported by NASA (7K to 22K) compared with the Chinese, who report a Q=117K :Quote from: Juan Yangthe resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively
Compare this with NASA's reported Q:
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Medium Efficiency(uN/W)
TE012 1880.4 22000 2.6 55.4 Air 21
TM2112 1932.6 7320 16.9 91.2 Air 5
TM2112 1936.7 18100 16.7 50.1 Air 3
TM212 1937.115 6726 50 66 Vacuum 1
NASA's reported Q for the vacuum experiment is a meager Q = 6726, which is 17 times smaller than the Chinese reported Q = 117495.
Also note that the most efficient mode reported by NASA Eagleworks is the Transverse Electric mode which gave a Mean Thrust of 55 uN with only 2.6 Watts.
The Chinese also report that they used the Transverse Electric mode
Instead, NASA Eagleworks has been running most of the experiments in the Brady report in the Transverse Magnetic mode, and the vacuum experiment also in the Transverse Magnetic mode, which NASA's own data (see above) shows to be the most inefficient mode.
Why is NASA running the vacuum experiment in the most inefficient mode (Transverse Magnetic) rather than the most efficient mode (Transverse Electric) ? Because they report difficulties in tuning the EM Drive under the Transverse Electric mode.Quote from: Brady et.al page 17Prior to the TM211 evaluations, COMSOL® analysis indicated that the TE012 was an effective thrust generation mode for the tapered cavity thruster being evaluated, so this mode was explored early in the evaluation process. Figure 22 shows a test run at the TE012 mode with an operating frequency of 1880.4 MHz. The measured quality factor was ~22,000, with a COMSOL prediction of 21,817. The measured power applied to the test article was measured to be 2.6 watts, and the (net) measured thrust was 55.4 micronewtons. With an input power of 2.6 watts, correcting for the quality factor, the predicted thrust is 50 micronewtons. However, since the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.
Why does NASA have difficulties running the EM Drive in the more efficient mode (the Transverse Electric mode) ? Because the most efficient mode results in greater shifting of its natural frequency with time. Hence I agree with Mulletron that instead of having the power concentrated at a frequency, for a problem where we know that the natural frequency of the EM Drive changes with time in a difficult to calculate and predict (with enough precision) manner, the best solution is to have the power distributed over a wider spectrum of frequencies, as done by Prof. Juan Yang in China.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778913;image)
Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
Now to put this idea to test, Q: What is the bandwidth of the resonant cavity and what is the 90 percent power bandwidth of the signal you are driving it with? What kind of sig gen are you using? Can it do FM? Can you do any advanced waveforms like a PSK waveform? Do you have a way to produce wideband noise or a spread spectrum carrier for your testing? Can you do any waveforms like at the bottom?
Also during researching other possible theories which could explain Emdrive we found ample literature stating that molecules acquire a kinetic momentum during the switching of the magnetic field as a result of its interaction with the vacuum field. If correct, that may well be a very significant lead. So that raises the question, how does one increase the switching rate? What about phase shifting? http://en.wikipedia.org/wiki/Phase-shift_keying
Phase shifting seems important.
https://www.viasat.com/files/assets/web/datasheets/EBEM_MD-1366_043_web.pdf
One of these driving your amp would be helpful. They go up to 2ghz.
(http://www.zdnet.com/i/story/60/03/000578/noise-from-microwave.png)
(https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTVRN3U7Ai7Zbu56xVIVRQhS_nMGHQFi5EjSx1BFaxm8GZOlY9Q)
(http://www.propagation.gatech.edu/ECE6390/project/Fall2008/DipoleDetectors/Di_Pole%20Detectors/images/DataLink_Spectrum.JPG)
(http://www.cse.iitk.ac.in/users/dheeraj/cs425/fig.lec01/bpsk.gif)
...When I was in charge of R&D laboratories for private companies I always welcomed such questions, particularly questions from outsiders that perhaps had not been asked by internal staff, because the purpose of R&D is always to find the truth as fast as possible, hence I saw it as a great benefit to our R&D efforts to get such questions. That was also the attitude of the Professors at MIT, I was lucky to work with.
Dr. Rodal:
You seem to ask a lot of "why" questions that could be better answered by getting yourself in the lab ...
... the main reason that we went with the lower-Q TM modes was because they consistently produced higher thrust levels for a given input power than the TE modes. ...The data reported by NASA Eagleworks contradicts that TM modes produce higher thrust levels than TE modes for a given input power:
Prior to the TM211 evaluations, COMSOL® analysis indicated that the TE012 was an effective thrust generation mode for the tapered cavity thruster being evaluated, so this mode was explored early in the evaluation process. Figure 22 shows a test run at the TE012 mode with an operating frequency of 1880.4 MHz. The measured quality factor was ~22,000, with a COMSOL prediction of 21,817. The measured power applied to the test article was measured to be 2.6 watts, and the (net) measured thrust was 55.4 micronewtons. With an input power of 2.6 watts, correcting for the quality factor, the predicted thrust is 50 micronewtons. However, since the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.
BTW, thanks much for the pointer to the 2014 Chinese report. Is there an English translation of same out in public yet? Also, in the 2013 Chinese report that had been translated into English, see attached, you will find that their large hundreds of milli-Newton thrust results were obtained with a loaded quality factor of just ~1,530 at 2.45 GHz, see figure 13 in their 2013 report. We think that is because that like any ac electric induction motor, this device has to load down its input energy/power source as it is generating thrusting work. Which brings up another point. That being all the calculated Q-Factors given in the Chinese papers, unless otherwise stated, is the very idealized unloaded Q-factors that implies that no energy is being extracted from the resonant cavity. We must keep that fact in mind as well...
Best, Paul M.
BTW, thanks much for the pointer to the 2014 Chinese report. Is there an English translation of same out in public yet?I have not seen an English translation of this paper posted in the Internet:
Paul - Thank you for this very helpful information@Paul March,
It is kind of important to my results if you could confirm that
... snip ...
Aero:
"It is kind of important to my results if you could confirm that the Teflon Rubber gaskets are installed as illustrated in the attached model."
I think what you are talking about is the initial pressure seal design for our aluminum frustum cavity that later went to a silicone O-ring and metal to metal compression shorting pad just inside the O-ring for both the large and small OD ends of the frustum.
The Eagleworks copper frustum is not a gas sealed unit, so all it has for its large and small OD end-cap interfaces are copper metal to copper metal interface with #6-32 brass cap-screws, nuts and bronze internal star lock washers spaced an average of 1.0" apart on the frustum's 0.50" wide copper flanges. As to the average air gap between these copper flanges due to their out of plane irregularities, (These copper flanges are only 0.040" thick.), my guess is that it can be no larger than 0.002" midway between the cap-screws.
"Right now, I am using a 12.5 mm coaxial dipole antenna at the inner face of the dielectric disk. I know you used a loop of some sort. How much do you think this difference matters considering that I am running a digital model?"
I've used various OD magnetic loops made from #20 AWG copper magnet wire soldered to SMA bulkhead connector that is mounted on the copper frustum's conical side wall, 15% of the of frustum Z-axis height from the large OD end of the frustum cavity, see attached picture. Currently we are using a 14.0mm OD loop antenna for our TM212 work at 1,937.118 MHz work.
"And while I'm at it, I read that the vacuum chamber is 30 inches by 36 inches, diameter by length. Is that inside or outside dimensions?"
The Eagleworks vacuum chamber interior dimensions are as noted except the distance front aluminum door to the rear domed portion of the 304L stainless steel spun end cap is ~38.0", see attached Kurt J. Lesker drawing. However, Our vacuum door is hinged on the right side of the chamber as viewed from the door end.
FYI for no good reason, here what I get w/o dielectricThe dimensions of the EM Drive are needed to estimate thrust in your formula as well as Shawyer's and McCulloch's formula. I could not find all the dimensions needed of the Chinese EM Drive tested by Prof. Juan Yang in any of their Chinese papers. My recollection is that @aero also tried to look for those dimensions in the Yang papers translated to English, and was unable to find the dimensions either.
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calc
TE012 1880.4 22000 2.6 55.4 16.9
TM212 1932.6 7320 16.9 91.2 60.5
TM212 1936.7 18100 16.7 50.1 146.9
TM212 1937.115 6726 50 66 163.3
How much of the table do we have for the Chinese ?
It looks from this drawing (see below) that the axial length of the Juan Yang truncated cone is significantly shorter than the small diameter, and therefore the Juan Yang truncated cone is significantly different from the one tested at NASA Eagleworks and Shawyer's Demo and Experimental truncated cones.
I wonder what kind of cash it costs to get some quality time with an additive/subtractive hybrid manufacturing 3D Printer/5 axis mills like the Lasertech series by DMG MORI, seen here fabricating a turbine housing:
https://www.youtube.com/watch?v=s9IdZ2pI5dA
These kinds of printers are capable of working with a variety of materials, including aluminum, steel alloys, inconel, titanium, etc. I suspect hybrid manufacturing of an Inconel cavity or other alloy could be the easiest, least expensive way of acquiring high precision resonance cavities with relatively consistent operational characteristics, but I have no idea how much it costs to work with these sorts of machines.
I wonder what kind of cash it costs to get some quality time with an additive/subtractive hybrid manufacturing 3D Printer/5 axis mills like the Lasertech series by DMG MORI, seen here fabricating a turbine housing:
https://www.youtube.com/watch?v=s9IdZ2pI5dA
These kinds of printers are capable of working with a variety of materials, including aluminum, steel alloys, inconel, titanium, etc. I suspect hybrid manufacturing of an Inconel cavity or other alloy could be the easiest, least expensive way of acquiring high precision resonance cavities with relatively consistent operational characteristics, but I have no idea how much it costs to work with these sorts of machines.
...
The question as to whether the EM Drive could be coupling to the Axion background came up on a different forum. I am dubious, and thought it would be useful to post why.
A recent review of axions as CDM: http://www.pnas.org/.../2015/01/07/1308788112.full.pdf
...
... the main reason that we went with the lower-Q TM modes was because they consistently produced higher thrust levels for a given input power than the TE modes. ...The data reported by NASA Eagleworks contradicts that TM modes produce higher thrust levels than TE modes for a given input power:
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Medium Efficiency(uN/W)
TE012 1880.4 22000 2.6 55.4 Air 21
TM2112 1932.6 7320 16.9 91.2 Air 5
TM2112 1936.7 18100 16.7 50.1 Air 3
TM212 1937.115 6726 50 66 Vacuum 1
Apparently, the emphasis should be on the use of the word "consistently" either as that
a) the reported Brady et.al. data for TE012 was inconsistent, in which case the Mean Thrust was not 55.4 uN as reported by Brady et.al. but apparently there is other unreported data that NASA has, giving significantly lower values of the thrust (and accordingly the reported Mean by Brady et.al. was not the true Mean of the TE012 experiments with the dielectric at NASA)
or
b) my interpretation of the Brady et.al.'s statement that NASA Eagleworks had trouble staying tuned at the natural frequency near 1880.4 MHzQuote from: Brady et.al page 17Prior to the TM211 evaluations, COMSOL® analysis indicated that the TE012 was an effective thrust generation mode for the tapered cavity thruster being evaluated, so this mode was explored early in the evaluation process. Figure 22 shows a test run at the TE012 mode with an operating frequency of 1880.4 MHz. The measured quality factor was ~22,000, with a COMSOL prediction of 21,817. The measured power applied to the test article was measured to be 2.6 watts, and the (net) measured thrust was 55.4 micronewtons. With an input power of 2.6 watts, correcting for the quality factor, the predicted thrust is 50 micronewtons. However, since the TE012 mode had numerous other RF modes in very close proximity, it was impractical to repeatedly operate the system in this mode, so the decision was made to evaluate the TM211 modes instead.
...
The question as to whether the EM Drive could be coupling to the Axion background came up on a different forum. I am dubious, and thought it would be useful to post why.
A recent review of axions as CDM: http://www.pnas.org/.../2015/01/07/1308788112.full.pdf
...
Just direct search
1308788112.full.pdf
Sorry if I confused you.
Are we to have axions or MiHsC?
Both are speculative but only one or none can be true, I think.
What do you chaps think?
Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
Now to put this idea to test, Q: What is the bandwidth of the resonant cavity and what is the 90 percent power bandwidth of the signal you are driving it with? What kind of sig gen are you using? Can it do FM? Can you do any advanced waveforms like a PSK waveform? Do you have a way to produce wideband noise or a spread spectrum carrier for your testing? Can you do any waveforms like at the bottom?
Also during researching other possible theories which could explain Emdrive we found ample literature stating that molecules acquire a kinetic momentum during the switching of the magnetic field as a result of its interaction with the vacuum field. If correct, that may well be a very significant lead. So that raises the question, how does one increase the switching rate? What about phase shifting? http://en.wikipedia.org/wiki/Phase-shift_keying
Phase shifting seems important.
https://www.viasat.com/files/assets/web/datasheets/EBEM_MD-1366_043_web.pdf
One of these driving your amp would be helpful. They go up to 2ghz.
Mulletron:
When using our current 14mm loop antenna optimized for the TM212 resonance at 1,937.118 MHz in our copper frustum, there were four RF resonances spaced +/- 30 MHz around the 2.45 GHz center frequency. And I assume that would also be the case using a higher power slot antenna in a similar location as the Chinese and Shawyer have done with their frustum resonant cavities. So yes, a wide bandwidth RF source seems to be called for and one that can be both AM and FM modulated at the same time. From my readings to date, that appears to be a hard nut to crack for solid state RF amplifiers at the desired kW power levels due to their limited RF power bandwidth capabilities, so we may be forced into using magnetrons and just learn how best to feed their 4-to-20 kV high voltage anode requirements while working in a hard vacuum. However the more difficult problems are finding ways of reducing their mass and size so we can "fly" them on our torque pendulum. Cooling the magnetrons in a hard vacuum is also another problem we need to deal with since air cooling is out of the question and liquid cooling is a giant pain to deal with as well. About the only other way to cool these beasts in a hard vacuum is to use phase change material like paraffin wax that could give us several minutes of run times before we had to let the accumulated heat in the paraffin radiate to the vacuum chamber walls.
BTW, the paraffin wax phase change cooling was used to good advantage on the lunar moon buggy used by NASA astronauts during their lunar explorations in the late 1960s and early 1970s during the USA Apollo Moon program.
Best, Paul M.
Dear aero;
Superb! My congratulations. Clearly, until proven otherwise, we now have to regard the anomalous results as a function of E&M interactions with the walls of the vacuum chamber.
We can forget about exotic theory and consider that the thrust force likely results from a little understood characteristic of evanescent waves and the forces they generate. Please pardon me if that steps on anyone's toesThis is hardly a workable theory of operation. There is nothing to back it up. Just conjecture. Not even one citation. Did anyone digest the reported facts that the device's thrust can be reversed simply by changing the resonant mode and/or the placement of the dielectric puck?
Did anyone digest the reported facts that the device's thrust can be reversed simply by changing the resonant mode and/or the placement of the dielectric puck?
@Paul March....Which modes were reverse?
However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map.
However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map.
This is non trivial.
This is hardly a workable theory of operation. There is nothing to back it up. Just conjecture. Not even one citation. Did anyone digest the reported facts that the device's thrust can be reversed simply by changing the resonant mode and/or the placement of the dielectric puck?
However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map.
And by the way, isn't a changed resonant frequency or mode the natural result from moving the dielectric from one end to the other in the tapered cavity?
aero - I heartily encourage you to keep at it.
...(Bold added for emphasis)
I have also cited this paper, http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf) several times. No feedback what-so-ever.
....
aero - I heartily encourage you to keep at it.
Do we know if MEEP adequately models the reactive near field? I don't see signs of it in the plots, but I do not trust my intituition, so things may be fine, but I thought I would ask.
Ok...time for me to embarrass myself here yet again.
Assuming for the moment, this device works not just in a vacuum chamber, but in space...
1) The frequency necessary to generate thrust varies with the internal (?) temperature.
2) The longer this device runs, the hotter it gets - 'Star Drive' reports major heating issues with low power test setups running for a few minutes (?) at a time. We are talking about a space version running nonstop for months or even years. To me, that sounds like a pretty extreme temperature increase - hundreds (?) thousands (?) of degrees, maybe.
So...would continual high temperatures damage the frustum over time? Or other parts of the device?
And might not the high temperatures...hmmm...act somehow to 'put the brakes' on the continual acceleration - increase to the point where the required frequency for thrust becomes unattainable, or at least reduced?
Te -------------------
-----
---
--
-
Tc ---------
Also...heat is energy, and this device, run for long periods in space, looks to produce a lot of heat. Could a portion of that heat be tapped and converted into electrical power, thus reducing the over all power requirements? Talking supplement here, not perpetual motion.
Ok, time to quit while I'm behind.
...Good observation. I do not see any evidence of the reactive near field at the boundaries of the upper picture (attached below) either.
Now, in this case, the entire chamber is in the near field of these 15 cm waves. Near fields can be pretty non-intuitive (for example, not weakening as 1/R^2). I would be especially wary of what's going on in the reactive near field (within 2 cm or so of the drive), which is likely to be non-intuitive even for near-fields.
Do we know if MEEP adequately models the reactive near field? I don't see signs of it in the plots, but I do not trust my intituition, so things may be fine, but I thought I would ask.
...
Also, please don't forget that static fields can cause forces. "It would be nice" to see a breakdown of force by cause here.
While this single run detected only 1/3 of the experimental measured value, I will brazenly write that I think we can forget about axions and dark matter. We can forget about exotic theory and consider that the thrust force likely results from a little understood characteristic of evanescent waves and the forces they generate.
Well, partly perhaps, but lets wait until I run the same model without the vacuum chamber. I have ran enough cases already that I feel confident that there will be forces in that case to.
While this single run detected only 1/3 of the experimental measured value, I will brazenly write that I think we can forget about axions and dark matter. We can forget about exotic theory and consider that the thrust force likely results from a little understood characteristic of evanescent waves and the forces they generate.Well, partly perhaps, but lets wait until I run the same model without the vacuum chamber. I have ran enough cases already that I feel confident that there will be forces in that case to.
Pardon the ignorance of this non-scientist, but with these results are you suggesting that the drive's thrust is only an interaction with the testing apparatus? In the second quote you say that you are confident that forces will be generated without a vacuum chamber. Does this mean that the drive would produce thrust in free space?
In these particular runs (which I believe is just the Drive and the chamber) the reactive near field is probably irrelevant, but for modeling the Drive + pendulum suspension it won't be.
Does MEEP support variable mesh sizes? It may be necessary to decrease the mesh size near structures.
And, for that matter, what is the mesh size in these plots? I think the rule of thumb is < lambda / 40, which is a little less than 4 mm.
(Note, by the way, that evanescent, or exponentially decaying, waves are just one part of near field behavior and not all near field waves have to rapidly decay, particularly if you have something like a waveguide set up.)
...Numerical Integration involves approximating definite integrals by summing discretized areas. This is not what the Finite Difference method does.
As for whether or not meep integrates the equations, I think it is a matter of terminology...
Pardon the ignorance of this non-scientist, but with these results are you suggesting that the drive's thrust is only an interaction with the testing apparatus? In the second quote you say that you are confident that forces will be generated without a vacuum chamber. Does this mean that the drive would produce thrust in free space?
...Numerical Integration involves approximating definite integrals by summing discretized areas. This is not what the Finite Difference method does.
As for whether or not meep integrates the equations, I think it is a matter of terminology...
I point the difference because it is important to understand the convergence problems with Finite Difference methods (as opposed to integration methods like the Boundary Element method, for example, or methods based on variational principles like the Finite Element Method).
What the Finite Difference method does is instead to approximate solutions to differential equations using finite differences to approximate derivatives.
The idea of a finite difference method is the transformation of a continuity domain to a discrete set of points, the mesh. In every grid point the given differential operator is approximated by a difference-operator.
The Finite Difference method is a very old method (references going back to the 19th century) but great progress was made using it during and after World War II, due to the development of the digital computer, due to Von Neuman and Friederichs.
At MIT's ASRL very complex Finite Difference codes were developed, for example the PETROS code:
http://bit.ly/1AJ5Vgt in addition to Finite Element and other types of numerical analyses.
1.) "are you suggesting that the drive's thrust is only an interaction with the testing apparatus?" I personally feel that that is the way to bet. In any case, such interactions must be exhaustively ruled out before we can consider this to be a "real" (i.e., new physics) effect. This is a small effect (10 micronewtons is the force a 1 mm chunk of ice exerts sitting on your hand), and this will not be trivial.
Including the vacuum chamber requires a lattice size of 26x31 x no-size, so all runs will be 2D with the vacuum chamber included. I tried to run a 3D but ran out of memory before resolution got as large as 10. That is not enough resolution to detect small features of the thruster cavity model and so is not useful for our purposes.Does 2-D here mean a
....
...That's useful information, as a uniform Finite Difference mesh size implies extremely long computer running times to get convergence in regions of steep gradient of the electromagnetic field. Otherwise steep gradient regions will not be well modeled.
No - meep does not support variable mesh size. ..
That's useful information, as a uniform Finite Difference mesh size implies extremely long computer running times to get convergence in regions of steep gradient of the electromagnetic field. Otherwise steep gradient regions will not be well modeled.
I've been following this thread as a lurker for a little while, but my knowledge is serverely lacking and have a lot of difficulty understanding what is being said. Is it the consensus at this point that it isn't a real effect, but merely experimental artefact?
Well, you can calculate it, or you can try and devise better experiments (e.g., the same test in a fiberglass chamber). In the end, I suspect it will take a test in space to really be sure, but that's expensive, so it is entirely proper to make it jump through all kinds of hoops here on the ground first. (And, note, it is quite possible that it will either be rejected or just fade away in the process.)
I can think of 3 ways to test the evanescent wave theory.
1) Is the measured thrust the same with the chamber door open and closed?
2) Is the thrust still there when the test article is rolled out of the chamber. Not sure if 2 is possible.....
3) Change the conditions near the resonant cavity; like wrap the thing in thick foam and then wrap all that with foil, see what the thrust does.
...
Marshall, how about these methods proposed by Mulletron to test whether the EM Drive thrust is due to evanescent wave interaction:
Change the conditions near the resonant cavity; like wrap the thing in thick foam and then wrap all that with foil, see what the thrust does.
what is the mesh size in these plots? I think the rule of thumb is < lambda / 40, which is a little less than 4 mm.
Have any tests been done reversing the drive?
They have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum.
.....Yes, and they have done it (reversing the drive) under hard vacuum.
Have any tests been done reversing the drive?
.....Yes, and they have done it (reversing the drive) under hard vacuum.
Have any tests been done reversing the drive?
Which seems to be a rather significant point.
They have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum.
QuoteThey have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum.
This needs to be redone.
+50 and -16 is evidence of systematic errors. It is simply not good enough to say (or imply), well, if we could redo it properly, it would be +- 50. That needs to be demonstrated (or not).
QuoteThey have now confirmed that there is a thrust signature in a hard vacuum (~5.0x10^-6 Torr) in both the forward direction, (approx. +50 micro-Newton (uN) with 50W at 1,937.115 MHz), and the reversed direction, (up to -16uN with a failing RF amp), when the thruster is rotated 180 degrees on the torque pendulum.
This needs to be redone.
+50 and -16 is evidence of systematic errors. It is simply not good enough to say (or imply), well, if we could redo it properly, it would be +- 50. That needs to be demonstrated (or not).
Give them a chance. Your enthusiasm is good but time is the best response here. Anyway Star Drive may if he is able to answer more specifically.:)
Well, you can calculate it, or you can try and devise better experiments (e.g., the same test in a fiberglass chamber). In the end, I suspect it will take a test in space to really be sure, but that's expensive, so it is entirely proper to make it jump through all kinds of hoops here on the ground first. (And, note, it is quite possible that it will either be rejected or just fade away in the process.)
Marshall, how about these methods proposed by Mulletron to test whether the EM Drive thrust is due to evanescent wave interaction:I can think of 3 ways to test the evanescent wave theory.
1) Is the measured thrust the same with the chamber door open and closed?
2) Is the thrust still there when the test article is rolled out of the chamber. Not sure if 2 is possible.....
3) Change the conditions near the resonant cavity; like wrap the thing in thick foam and then wrap all that with foil, see what the thrust does.
...
...
Have any tests been done reversing the drive?
Yes, evanescent waves are propagating waves. They propagate in the direction of the interface, so their momentum is parallel to the boundary. It is just their amplitude that decays exponentially away from the interface layer.So in this context, evanescent waves "hug" the boundary. The propagate parallel to the boundary. They do not radiate away from the boundary. Their amplitude falls exponentially with distance, unlike radiating waves which fall off with inverse square. The above quote from Polywell matches any check of the literature online.
They are formed at the boundary between two media with different wave motion properties, and are most intense within one third of a wavelength from the surface of formation.The 1/3 wavelength figure also appears in other references. Evanescent fields would be most intense within .05m or ~2 inches from the conical frustum. Any structure within that range is subject to scrutiny.
Momentum and spin represent fundamental dynamic properties of quantum particles and fields. In particular, propagating optical waves (photons) carry momentum and longitudinal spin determined by the wave vector and circular polarization, respectively. Here we show that exactly the opposite can be the case for evanescent optical waves. A single evanescent wave possesses a spin component, which is independent of the polarization and is orthogonal to the wave vector. Furthermore, such a wave carries a momentum component, which is determined by the circular polarization and is also orthogonal to the wave vector.
Shawyer's statement, "The small end diameters are set just above the cut-off diameter corresponding to the mode and frequency of the design."http://forum.nasaspaceflight.com/index.php?topic=29276.msg1275094#msg1275094
To be thorough, if "the drive" means the pillbox-shaped cavity that's correct, if the "the drive" means the truncated cone (frustum), no:...
Have any tests been done reversing the drive?
Both the test run that was reported on in Brady et al and the test run that Star-Drive talked about have included running the drive in a reverse orientation.
To be thorough, if "the drive" means the pillbox-shaped cavity that's correct, if the "the drive" means the truncated cone (frustum), no:...
Have any tests been done reversing the drive?
Both the test run that was reported on in Brady et al and the test run that Star-Drive talked about have included running the drive in a reverse orientation.
Only the Cannae pillbox cavity was reported to run in a reversed configuration in the Brady et.al. report ( http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf ), on test runs 1B and 2B, as reported in the text, and summarized in Table 1. Cannae Testing: Summary of Results and Conclusions and illustrated on Figure 11. Cannae Test Article on Torsion Pendulum (thrust to the right, a.k.a. reverse orientation).
The Brady et.al. paper does not report a single test with the truncated cone (frustum) run in the reverse configuration.
The first instance in which the truncated cone was reported to have been run in a reverse configuration is the recent disclosure by Paul March, under hard vacuum.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635481;image)
Aside from re running the reverse orientation tests. Are there any other tests that Eagleworks needs to run. I am aware that they need to get to a certain performance level before then can hand off for replication attempt. But for the life of me the only other test case I can think of wanting results for is
* Re Run frustum reverse orientation in Hard vacuum
* Run forward and reverse orientation of frustum in a null configuration
Aside from re running the reverse orientation tests. Are there any other tests that Eagleworks needs to run. I am aware that they need to get to a certain performance level before then can hand off for replication attempt. But for the life of me the only other test case I can think of wanting results for is
* Re Run frustum reverse orientation in Hard vacuum
* Run forward and reverse orientation of frustum in a null configuration
If it is handed off for a replication attempt, is this to be done in more than one other location, in other words are multiple teams to attempt this or just one?
How hard would it be to put the 1165 inside a more vacuum resilient container?This appears to be a great finding, Mulletron, thanks for pointing it out. If the Amp that Eagleworks has been using is not rated for the hard vacuum (5*10^(-4) Torr) in their tests, do you have a best suggestion on how they should proceed?
http://www.empowerrf.com/pdfs/1165.pdf
Notice the paper says max altitude 50K feet!
It is operating beyond specs in that vacuum.....why they keep dying!
We gotta figure this out, pronto!
Nope, sealing things up like that is beyond my expertise. No clue how to help. Anyone?How hard would it be to put the 1165 inside a more vacuum resilient container?This appears to be a great finding, Mulletron, thanks for pointing it out. If the Amp that Eagleworks has been using is not rated for the hard vacuum (5*10^(-4) Torr) in their tests, do you have a best suggestion on how they should proceed?
http://www.empowerrf.com/pdfs/1165.pdf
Notice the paper says max altitude 50K feet!
It is operating beyond specs in that vacuum.....why they keep dying!
We gotta figure this out, pronto!
I think this definitively puts evanescent wave theories to bed.
Nope, sealing things up like that is beyond my expertise. No clue how to help. Anyone?How hard would it be to put the 1165 inside a more vacuum resilient container?This appears to be a great finding, Mulletron, thanks for pointing it out. If the Amp that Eagleworks has been using is not rated for the hard vacuum (5*10^(-4) Torr) in their tests, do you have a best suggestion on how they should proceed?
http://www.empowerrf.com/pdfs/1165.pdf
Notice the paper says max altitude 50K feet!
It is operating beyond specs in that vacuum.....why they keep dying!
We gotta figure this out, pronto!
So why does it have to be inside the chamber again? Can't rf be piped in somehow?
@MulletronQuoteI think this definitively puts evanescent wave theories to bed.
It does if we credit you with knowing everything that is to be known about evanescent waves.
I recognize that you have researched the literature on this topic extensively and while I am willing to credit you with knowing everything that is known about evanescent waves, I'm not prepared to take that last step and credit that that is everything that is to be known.
We know that evanescent waves couple quite strongly with identically generated waves out of phase, if the sources are near enough to each other. There could be and probably is this type of coupling between the two ends of the cavity. That coupling should only stress the cavity material though and I don't know how it would produce thrust.
Dr. Rodel seems to have shot down my thought of evanescent wave photons escaping the cavity superluminally even though there have been several papers published claiming that evanescent waves, under the right conditions, do carry superluminal momentum. (Google it.)
So we're coming around to the thought that there may be a whole bunch of electromagnetic energy in the vacuum chamber in the form of waves, some of them of the correct wavelength and phase to couple with the evanescent waves escaping from the thruster cavity. If such waves are transient, then could the ... and so forth. Isn't this Dr. White's theory?
@MulletronQuoteI think this definitively puts evanescent wave theories to bed.
It does if we credit you with knowing everything that is to be known about evanescent waves.
I recognize that you have researched the literature on this topic extensively and while I am willing to credit you with knowing everything that is known about evanescent waves, I'm not prepared to take that last step and credit that that is everything that is to be known.
We know that evanescent waves couple quite strongly with identically generated waves out of phase, if the sources are near enough to each other. There could be and probably is this type of coupling between the two ends of the cavity. That coupling should only stress the cavity material though and I don't know how it would produce thrust.
Dr. Rodel seems to have shot down my thought of evanescent wave photons escaping the cavity superluminally even though there have been several papers published claiming that evanescent waves, under the right conditions, do carry superluminal momentum. (Google it.)
So we're coming around to the thought that there may be a whole bunch of electromagnetic energy in the vacuum chamber in the form of waves, some of them of the correct wavelength and phase to couple with the evanescent waves escaping from the thruster cavity. If such waves are transient, then could the ... and so forth. Isn't this Dr. White's theory?
@MulletronQuoteI think this definitively puts evanescent wave theories to bed.
It does if we credit you with knowing everything that is to be known about evanescent waves.
I recognize that you have researched the literature on this topic extensively and while I am willing to credit you with knowing everything that is known about evanescent waves, I'm not prepared to take that last step and credit that that is everything that is to be known.
We know that evanescent waves couple quite strongly with identically generated waves out of phase, if the sources are near enough to each other. There could be and probably is this type of coupling between the two ends of the cavity. That coupling should only stress the cavity material though and I don't know how it would produce thrust.
Dr. Rodel seems to have shot down my thought of evanescent wave photons escaping the cavity superluminally even though there have been several papers published claiming that evanescent waves, under the right conditions, do carry superluminal momentum. (Google it.)
So we're coming around to the thought that there may be a whole bunch of electromagnetic energy in the vacuum chamber in the form of waves, some of them of the correct wavelength and phase to couple with the evanescent waves escaping from the thruster cavity. If such waves are transient, then could the ... and so forth. Isn't this Dr. White's theory?
I'm not hostile to evanescent waves. I've spent months reading about them. I have lots to learn. The only analogue to have evanescent waves production like this is using light and thin metal films. Thin metals every time I look. For example, copper actually does have a refractive index if it is really thin. Thin films of metal behave like dielectrics. This would satisfy the surface plasmon polaritron idea. But the thickness of the frustum is many many times thicker than skin depth at 2ghz of 1.45um to 1.67um depending on what resource I use.
http://en.wikipedia.org/wiki/Surface_plasmon
http://en.wikipedia.org/wiki/Surface_plasmon_polariton
http://en.wikipedia.org/wiki/Surface_plasmon_resonance
http://refractiveindex.info/?shelf=main&book=Cu&page=Rakic
http://www.microwaves101.com/encyclopedias/skin-depth-calculator
I'm very sure it isn't evanescent waves. However that doesn't stop anybody from proving me wrong.
@ RODAL
Arrgh, Mondays !
Looked over my bleary weekend, noticed I was using diameters AGAIN !
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calculated w/o
dielectric
TE012 1880.4 22000 2.6 55.4 10.8
TM212 1932.6 7320 16.9 91.2 38.5
TM212 1936.7 18100 16.7 50.1 93.5
TM212 1937.115 6726 50 66 104.0
Anyway, shows it pays to rewrite everything in the same place !
....
One of seven types of hypothetical space drives suggested by Marc Millis of the Breakthrough Propulsion Physics Program at NASA's Glenn Research Center (see Millis drives).http://www.daviddarling.info/encyclopedia/I/induction_sail.html
The radiation pressure on one side of the induction sail would be increased by some yet undiscovered means, and the pressure on the other side lowered. The spacecraft would move toward the low-pressure region.
Nope, sealing things up like that is beyond my expertise. No clue how to help. Anyone?How hard would it be to put the 1165 inside a more vacuum resilient container?This appears to be a great finding, Mulletron, thanks for pointing it out. If the Amp that Eagleworks has been using is not rated for the hard vacuum (5*10^(-4) Torr) in their tests, do you have a best suggestion on how they should proceed?
http://www.empowerrf.com/pdfs/1165.pdf
Notice the paper says max altitude 50K feet!
It is operating beyond specs in that vacuum.....why they keep dying!
We gotta figure this out, pronto!
So why does it have to be inside the chamber again? Can't rf be piped in somehow?
Folks:
The reason I thought that the EMPower unit could take vacuum is that the first page of the data sheet indicated that they are "hermetically" sealed. At NASA hermetically sealed always means vacuum rated. The Air Force and her contractors obviously have another definition of that word, but my bad for assuming it meant the NASA definition. In any regards and as I stated earlier, EMPower has given us permission to just drill a hole into the top plate of their amp's chassis so it can vent to hard vacuum conditions when operating in same, since there are no components in their unit that would degrade over time in a hard vacuum such as electrolytic caps.
Best, Paul M.
Aside from re running the reverse orientation tests. Are there any other tests that Eagleworks needs to run. I am aware that they need to get to a certain performance level before then can hand off for replication attempt. But for the life of me the only other test case I can think of wanting results for is
* Re Run frustum reverse orientation in Hard vacuum
* Run forward and reverse orientation of frustum in a null configuration
If it is handed off for a replication attempt, is this to be done in more than one other location, in other words are multiple teams to attempt this or just one?
My understanding is given what was said in the conclusion of the Brady et al paper is that they want to create a testable unit to be used by Glen Research Center and JPL and Johns Hopkins. However, I believe of the two NASA centers only Glen has signed on. No clue on whether or not Johns Hopkins has also signed on. Which is the reason they need to get the thrust levels up because the Balance at Glen has a much higher floor of detectable thrust.
@ RODAL
Arrgh, Mondays !
Looked over my bleary weekend, noticed I was using diameters AGAIN !
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calculated w/o
dielectric
TE012 1880.4 22000 2.6 55.4 10.8
TM212 1932.6 7320 16.9 91.2 38.5
TM212 1936.7 18100 16.7 50.1 93.5
TM212 1937.115 6726 50 66 104.0
Anyway, shows it pays to rewrite everything in the same place !
....
Great !
In order to understand the above, (please correct me if I am wrong), you used in your formula the actual frequency and mode shapes that took place in the EM Drive experiment with the dielectric so in that sense you did calculate with the dielectric in a very restricted sense.
It will help to improve radiation of heat by adding low emissivity heat sinks to the locations that get most heated. Lowering the emissivity of what is usually shiny aluminum, will improve radiation and decrease the temperature. A thin coat of non reflective, flat paint on the inside and outside surfaces, and a thin coat on the hot parts will allow up to six times the amount of power to radiate for the same component temperature rise. Anodizing works almost as well, provided the anodized surface is about .001” thick.Nope, sealing things up like that is beyond my expertise. No clue how to help. Anyone?How hard would it be to put the 1165 inside a more vacuum resilient container?This appears to be a great finding, Mulletron, thanks for pointing it out. If the Amp that Eagleworks has been using is not rated for the hard vacuum (5*10^(-4) Torr) in their tests, do you have a best suggestion on how they should proceed?
http://www.empowerrf.com/pdfs/1165.pdf
Notice the paper says max altitude 50K feet!
It is operating beyond specs in that vacuum.....why they keep dying!
We gotta figure this out, pronto!
So why does it have to be inside the chamber again? Can't rf be piped in somehow?
Folks:
The reason I thought that the EMPower unit could take vacuum is that the first page of the data sheet indicated that they are "hermetically" sealed. At NASA hermetically sealed always means vacuum rated. The Air Force and her contractors obviously have another definition of that word, but my bad for assuming it meant the NASA definition. In any regards and as I stated earlier, EMPower has given us permission to just drill a hole into the top plate of their amp's chassis so it can vent to hard vacuum conditions when operating in same, since there are no components in their unit that would degrade over time in a hard vacuum such as electrolytic caps.
Best, Paul M.
If the 1165 amplifier is "NASA" hermetically sealed the reason for a 50,000 ft ceiling may be to limit distortion of the internal compartments of the unit, resulting in out of spec performance. Drilling one hole may not do it because there is no guarantee every part of the amplifier will vent.
Heat dissipation is a lot more difficult in a vacuum since just about all the heat has to escape by radiation. Maybe pre-cooling the copper cavity will help. A class C amplifier would be more efficient and would work just as well if a CW output was used. But class C amplifiers are not linear amps. The output goes from a low level to the maximum design power level with hardly any change in input level.
Getting back to the 1165 amp: It is class AB so has an efficiency < 75% provided the load is 50 Ohms resistive. It also can't handle an SWR > 3:1. One way to protect the amplifier is to put a circulator between it and the em-drive. The reflected wave from the em-drive gets dissipated as heat in the circulator instead of the amplifier. Or worse the resulting high RF voltages at the output of the amplifier cause arcing.
Since the em-drive has such a high Q it's next to impossible to drive it with the right frequency. The frequency will always be off so the complex impedance at the input of the em-drive will almost never be 50 Ohms resistive. This results in most of the power being reflected back to the amplifier, damaging it. , Instead of using a signal generator, if the cavity was the frequency determining element then locking to the desired frequency might be easier. Cavity oscillators have been around for a long time. High power cavity oscillators use tubes. (Eimac)
@ RODAL
Arrgh, Mondays !
Looked over my bleary weekend, noticed I was using diameters AGAIN !
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calculated w/o
dielectric
TE012 1880.4 22000 2.6 55.4 10.8
TM212 1932.6 7320 16.9 91.2 38.5
TM212 1936.7 18100 16.7 50.1 93.5
TM212 1937.115 6726 50 66 104.0
Anyway, shows it pays to rewrite everything in the same place !
....
Great !
In order to understand the above, (please correct me if I am wrong), you used in your formula the actual frequency and mode shapes that took place in the EM Drive experiment with the dielectric so in that sense you did calculate with the dielectric in a very restricted sense.
FYI
Cleanup and de-typo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity, no dielectric)
Starting with the expressions for the frequency of a cylindrical RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[sub m,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into Doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
Slow goin', thanks for your patience.
When I apply boundary conditions, Er must be zero at the side walls so P0n(cos(θw)) = 0 can only happen for specific angles. If the wall is not at the right angle, Er must be zero every where. Same is true for Eϕ, but that has zeros for P1n(cos(θw)) so it would be a different mode.
...
In other words, if the EmDrive guys don't build the cavity to specific angles, it will simply reflect all power and won't have any RF in it at all!
....Please tell us more when you have a chance about the <<self-accelerating Dirac wavepacket (which does conserve momentum)>> as conservation of momentum has been the biggest problem of the scientific media (Prof. Baez and Sean Carroll for example) and with the serious science-fiction media (Greg Egan) with the EMDrive. How does momentum get conserved in the EMDrive when there is nothing coming out of the EM Drive?
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
...
Or, taking the highest thrust value (rather than the truncated upper mean of the experimental trace), (disregarding turn on transients) which is 78 μN (see trace below) one would get an excellent comparison with NotSoSureOfIt's dielectric-weighted prediction in vacuum of 87 μN: barely 11% difference !@ RODAL
Arrgh, Mondays !
Looked over my bleary weekend, noticed I was using diameters AGAIN !
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calculated w/o
dielectric
TE012 1880.4 22000 2.6 55.4 10.8
TM212 1932.6 7320 16.9 91.2 38.5
TM212 1936.7 18100 16.7 50.1 93.5
TM212 1937.115 6726 50 66 104.0
Anyway, shows it pays to rewrite everything in the same place !
....
Great !
In order to understand the above, (please correct me if I am wrong), you used in your formula the actual frequency and mode shapes that took place in the EM Drive experiment with the dielectric so in that sense you did calculate with the dielectric in a very restricted sense.
FYI
Cleanup and de-typo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity, no dielectric)
Starting with the expressions for the frequency of a cylindrical RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[sub m,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into Doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
Slow goin', thanks for your patience.
Excellent! Thank you for posting the complete equations.
One suggestion: In the expression NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
the speed of light in vacuum "c" appears in the numerator without being divided by the SquareRoot of the relative electric permittivity and relative magnetic permeability.
Since the relative electric permittivity of the dielectric is 2.3, this would decrease the values in the table by a factor of Sqrt[2.3]=1.52 if the whole cavity would be occupied by the dielectric. Granted that only a portion of the truncated cone contains the dielectric, which will decrease the dividing factor, but any amount will reduce the effective value of c in the medium, giving lower thrust and hence values closer to the experimental measurements.
For example, very roughly, assuming that 1/3 of the longitudinal length is occupied by the dielectric, and using the average as a medium with those average properties, Sqrt[(2.3*1/3)+1*(2/3)]=1.20, the thrust values would be reduced by a factor of 1.20, so for the most important test (the one in recently performed in vacuum, -the other experimental values may have been affected by thermal convection effects in the air and are therefore less reliable-), instead of 104 μN you would get 87 μN, which better compares with the experimental value of 66 μN.
@ RODALThat makes for such an attractive setup, that anyone would gladly trudge through 7 ft of snow ! :)
PS: Got plenty of big vacuum chambers here, (couple 6' x 8' cylinders, etc.) no torsion balances left though (not put together anyway .. might have parts) and a big lack of time !
@ RODALThat makes for such an attractive setup, that anyone would gladly trudge through 7 ft of snow ! :)
PS: Got plenty of big vacuum chambers here, (couple 6' x 8' cylinders, etc.) no torsion balances left though (not put together anyway .. might have parts) and a big lack of time !
...Numerical Integration involves approximating definite integrals by summing discretized areas. This is not what the Finite Difference method does.
As for whether or not meep integrates the equations, I think it is a matter of terminology...
Sorry about being perhaps overly rigorous in the use of the word "integrate". I point this (finite? pun-intended :) ) difference because it is important to understand the convergence problems with Finite Difference methods (as opposed to integration methods like the Boundary Element method, for example, or methods based on variational principles like the Finite Element Method).
What the Finite Difference method does is instead to approximate solutions to differential equations using finite differences to approximate derivatives.
The idea of a finite difference method is the transformation of a continuity domain to a discrete set of points, the mesh. In every grid point the given differential operator is approximated by a difference-operator.
The issue is that numerically, numerical differentiation is always a much trickier problem than numerical integration (from a convergence viewpoint).
The Finite Difference method is a very old method (references going back to the 19th century) but great progress was made using it during and after World War II, due to the development of the digital computer, due to Von Neuman and Friederichs, mainly due to the Manhattan Project.
At MIT's ASRL very complex Finite Difference codes were developed, for example the PETROS code:
http://bit.ly/1AJ5Vgt (http://bit.ly/1AJ5Vgt) in addition to Finite Element and other types of numerical analyses.
....That's why it is critical, to assess results of a numerical solution, to compare the results of a numerical solution (for example Finite Difference method) to an exact solution. In this case, an exact solution to a cylindrical cavity exists (http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity), and it would be worthwhile to compare how far is the MEEP solution for a resonant cylindrical cavity, say of a diameter=Sqrt[BigDiameterOfTruncatedCone * SmallDiameterOfTruncatedCone] and same axial length, with the same material inputs and mesh as used for the Finite Difference solution of the Truncated Cone.
To-wit: Finite Element methods give you both an approximation to the exact solution and a measure of how good that approximation is, even if the exact solution is not easily obtained. Finite Difference schemes provide no such information regarding the correctness of the results they provide.
Has anyone looked at rangling some cloud vm time to run these processes.
You can find the amazon compute vm prices here
http://aws.amazon.com/ec2/pricing/
and the azure compute vm prices here
http://azure.microsoft.com/en-us/pricing/details/virtual-machines/
not sure what the runtime looks like but I would hazard a guess that you could figure out a cheap enough solution that allows you to get results in the least amount of time.
Has anyone looked at rangling some cloud vm time to run these processes.
You can find the amazon compute vm prices here
http://aws.amazon.com/ec2/pricing/
and the azure compute vm prices here
http://azure.microsoft.com/en-us/pricing/details/virtual-machines/
not sure what the runtime looks like but I would hazard a guess that you could figure out a cheap enough solution that allows you to get results in the least amount of time.
I've looked at it but I'm not going to take the responsibility of paying for and trying to figure out how to use their systems, and to install and use meep on those systems.
I do have an opinion. The most understandable documentation of the available capabilities is from Google.
https://cloud.google.com/compute/pricing (https://cloud.google.com/compute/pricing)
But at only 100 GB memory for a high memory compute configuration, I'd be concerned about size of the model. For a 3D model, Meep memory requirements go up by a factor of 8 for each doubling of the resolution and compute requirements by a factor of 16 for the same doubling.
If someone wanted to do this, it would be necessary to establish the model at low resolution on a convenient machine, then calculate the resources needed by the problem running at the resolution required for viable results.
Meep was designed to run massive problems at high resolution on supercomputers. Sixteen processors each with 6.5 GB ram is not really a very impressive supercomputer. And I wonder, can these cloud based compute engines guarantee model execution synchronization for the duration of a run that may consume hours of CPU? If it can't be synchronized then AIUI all the CPU's wait for the slowest partition to keep up. That could get costly in a hurry.
I have designed and priced a custom computer that could provide a very good basis for estimating the resources needed to run high fidelity problems. It was priced at $2038.96 (USD), a firm quote, tax included. It is about 1/3 the machine referred to above. (Six cores with 32 GB DDR4 memory) I'm not going to take the responsibility for paying for that machine, either, though I would love to have it.
The EmDrive's resonant cavity has the characteristics as of cutoff waveguide. By reference to the phenomena of electromagnetic wave anomalous propagation in the cutoff waveguide, the fact that the electromagnetic wave can be reflected without metal surface in the cutoff waveguide is presented in the paper.At the same time, another fact that the electromagnetic wave distribution in the EmDrive's resonant cavity showing a characteristic of evanescent wave is presented also. It is a kind of electromagnetic wave anomalous propagation. This anomalous propagation can be described by the photon tunneling effect, consistent with quantum field theory.At last,the opinion that EmDrive revealing some properties of background vacuum is put forward in the paper,and the introduction of the virtual photon process may be a new method to analyze the momentum conservation of EmDrive.
https://iafastro.directory/iac/archive/browse/IAC-13/C4/P/16863/Great article, Mulletron, thank you for bringing it to our attention.
...
Nice to know someone has looked at it. Was just wondering if these computation limitations could be simply solved by the application of a little sprinkle of the cloud. As for paying for access to the resources, I guess the question is how badly do we want accurate results.
Has anyone looked at rangling some cloud vm time to run these processes.
You can find the amazon compute vm prices here
http://aws.amazon.com/ec2/pricing/
and the azure compute vm prices here
http://azure.microsoft.com/en-us/pricing/details/virtual-machines/
not sure what the runtime looks like but I would hazard a guess that you could figure out a cheap enough solution that allows you to get results in the least amount of time.
I've looked at it but I'm not going to take the responsibility of paying for and trying to figure out how to use their systems, and to install and use meep on those systems.
I do have an opinion. The most understandable documentation of the available capabilities is from Google.
https://cloud.google.com/compute/pricing (https://cloud.google.com/compute/pricing)
But at only 100 GB memory for a high memory compute configuration, I'd be concerned about size of the model. For a 3D model, Meep memory requirements go up by a factor of 8 for each doubling of the resolution and compute requirements by a factor of 16 for the same doubling.
If someone wanted to do this, it would be necessary to establish the model at low resolution on a convenient machine, then calculate the resources needed by the problem running at the resolution required for viable results.
Meep was designed to run massive problems at high resolution on supercomputers. Sixteen processors each with 6.5 GB ram is not really a very impressive supercomputer. And I wonder, can these cloud based compute engines guarantee model execution synchronization for the duration of a run that may consume hours of CPU? If it can't be synchronized then AIUI all the CPU's wait for the slowest partition to keep up. That could get costly in a hurry.
I have designed and priced a custom computer that could provide a very good basis for estimating the resources needed to run high fidelity problems. It was priced at $2038.96 (USD), a firm quote, tax included. It is about 1/3 the machine referred to above. (Six cores with 32 GB DDR4 memory) I'm not going to take the responsibility for paying for that machine, either, though I would love to have it.
Nice to know someone has looked at it. Was just wondering if these computation limitations could be simply solved by the application of a little sprinkle of the cloud. As for paying for access to the resources, I guess the question is how badly do we want accurate results.
Has anyone looked at rangling some cloud vm time to run these processes.
You can find the amazon compute vm prices here
http://aws.amazon.com/ec2/pricing/
and the azure compute vm prices here
http://azure.microsoft.com/en-us/pricing/details/virtual-machines/
not sure what the runtime looks like but I would hazard a guess that you could figure out a cheap enough solution that allows you to get results in the least amount of time.
I've looked at it but I'm not going to take the responsibility of paying for and trying to figure out how to use their systems, and to install and use meep on those systems.
I do have an opinion. The most understandable documentation of the available capabilities is from Google.
https://cloud.google.com/compute/pricing (https://cloud.google.com/compute/pricing)
But at only 100 GB memory for a high memory compute configuration, I'd be concerned about size of the model. For a 3D model, Meep memory requirements go up by a factor of 8 for each doubling of the resolution and compute requirements by a factor of 16 for the same doubling.
If someone wanted to do this, it would be necessary to establish the model at low resolution on a convenient machine, then calculate the resources needed by the problem running at the resolution required for viable results.
Meep was designed to run massive problems at high resolution on supercomputers. Sixteen processors each with 6.5 GB ram is not really a very impressive supercomputer. And I wonder, can these cloud based compute engines guarantee model execution synchronization for the duration of a run that may consume hours of CPU? If it can't be synchronized then AIUI all the CPU's wait for the slowest partition to keep up. That could get costly in a hurry.
I have designed and priced a custom computer that could provide a very good basis for estimating the resources needed to run high fidelity problems. It was priced at $2038.96 (USD), a firm quote, tax included. It is about 1/3 the machine referred to above. (Six cores with 32 GB DDR4 memory) I'm not going to take the responsibility for paying for that machine, either, though I would love to have it.
Nice to know someone has looked at it. Was just wondering if these computation limitations could be simply solved by the application of a little sprinkle of the cloud. As for paying for access to the resources, I guess the question is how badly do we want accurate results.
Not so much accurate results. The results I have presented are accurate to second order, for the problem evaluated. More like more representative problems, higher fidelity models (3D, and resolving smaller gaps, for example), that could be achieved with more computing power.
I have calculated error bounds, the magnitude of step size squared for my current run, which I hope to post in about 6 hours.
delta s ~= 0.023 mm = 0.000023 meters, (delta s)^2 =5.29E-010
delta t ~= 0.0001071422 sec, (delta t)^2 = 1.1479455161248E-008 s^2
Those error bounds seem acceptable to me for the problems I am evaluating. The errors inherent in the problem formulated to represent characteristics of the actual EM thurster/vacuum chamber are far, far larger than the computational errors of the simulation.
I kind of wish people would stop posting their concern about numerical computational deficiencies here. If they have a valid concern then they really should take it up with MIT, where the codes were written, or perhaps ONR, DARPA who spent the money to pay for the development. Maybe ONR/DARPA should ask for their money back?
Or PM me, I can point them to several online sites giving results that scrutinise meep accuracy.
...Actually the basis of the exact solution (for the truncated cone microwave cavity) goes back to the great US engineer Schelnukoff in 1938 . ...
He crossed Siberia into Manchuria and then Japan before settling into Seattle in 1921. There he received bachelor's and master's degrees in mathematics from the State College of Washington, now the University of Washington, and in 1928 received his Ph.D. from Columbia University for his dissertation On Certain Properties of the Metrical and Generalized Metrical Groups in Linear Spaces of n Dimension.
....
, Schelkunoff joined Western Electric's research wing, which became Bell Laboratories. In 1933 he and Sally P. Mead began analysis of waveguide propagation discovered analytically by their colleague George C. Southworth. Their analysis uncovered the transverse modes. Schelkunoff appears to have been the first to notice the important practical consequences of the fact that attenuation in the TE01 mode decays inversely with the 3/2 power of the frequency. In 1935 he and his colleagues reported that coaxial cable, then new, could transmit television pictures or up to 200 telephone conversations.
...As discussed here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332799#msg1332799, those error bounds do not tell you about what can be the difference between a Finite Difference solution and an exact solution to the problem. Magnitude of step size is instead related, for example, to the stability problems of the Finite Difference operator, as it was shown by Friedrichs and Lax. For example, the central-difference operator has stability problems that mandate the time step to be smaller than a certain bound, because it is an explicit (as opposed to implicit) finite difference operator. However, having a step small enough to avoid instability of the finite difference operator does not tell you about how far can the finite difference solution be from an exact solution.
I have calculated error bounds, the magnitude of step size squared for my current run, which I hope to post in about 6 hours.
delta s ~= 0.023 mm = 0.000023 meters, (delta s)^2 =5.29E-010
delta t ~= 0.0001071422 sec, (delta t)^2 = 1.1479455161248E-008 s^2
Those error bounds seem acceptable to me for the problems I am evaluating. The errors inherent in the problem formulated to represent characteristics of the actual EM thurster/vacuum chamber are far, far larger than the computational errors of the simulation.
I kind of wish people would stop posting their concern about numerical computational deficiencies here. If they have a valid concern then they really should take it up with MIT, where the codes were written, or perhaps ONR, DARPA who spent the money to pay for the development. Maybe ONR/DARPA should ask for their money back?
...
We are discussing the NASA experiments, and the proposed theoretical explanations, asking and examining all kinds of questions. Numerical solutions (related to EM Drive Developments - space flight applications) deserve equal examination, not less, than the examination of experiments and the examination of theoretical explanations.
...Same thing I proposed here:
So what do you propose as a resolution to your critique?
.. it is critical, to assess results of a numerical solution, to compare the results of a numerical solution (for example Finite Difference method) to an exact solution. In this case, an exact solution to a cylindrical cavity exists (http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity), and it would be worthwhile to compare how far is the MEEP solution for a resonant cylindrical cavity, say of a diameter=Sqrt[BigDiameterOfTruncatedCone * SmallDiameterOfTruncatedCone]=0.21060 m and same axial length, with the same material inputs and mesh as used for the Finite Difference solution of the Truncated Cone.
....
The accuracy issues we are discussing are not related to any bugs or issues concerning the people at MIT that wrote the program, they are issues inherent to the Finite Difference method. All numerical methods have numerical issues of different kinds.
The purpose to discuss these issues here in an open forum is to examine the numerical solutions concerning EM Drive for space flight applications, just like we examine the experiments and the theoretical explanations. :)
We are discussing the NASA experiments, and the proposed theoretical explanations, asking and examining all kinds of questions. Numerical solutions (related to EM Drive Developments - space flight applications) deserve equal examination, not less, than the examination of experiments and the examination of theoretical explanations.
....Please tell us more when you have a chance about the <<self-accelerating Dirac wavepacket (which does conserve momentum)>> as conservation of momentum has been the biggest problem of the scientific media (Prof. Baez and Sean Carroll for example) and with the serious science-fiction media (Greg Egan) with the EMDrive. How does momentum get conserved in the EMDrive when there is nothing coming out of the EM Drive?
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
...
http://physics.stackexchange.com/questions/160702/self-accelerating-wavepackets-what-are-they-and-can-they-impulse-a-spaceship
http://www.nature.com/nphys/journal/vaop/ncurrent/fig_tab/nphys3196_F1.html
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
Or are you considering that evanescent waves coming out of the EM Drive in outer space (with no fields or matter nearby to interact with) are responsible for conservation of momentum with an effectiveness much greater than a photon rocket?
...Same thing I proposed here:
So what do you propose as a resolution to your critique?
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332813#msg1332813.. it is critical, to assess results of a numerical solution, to compare the results of a numerical solution (for example Finite Difference method) to an exact solution. In this case, an exact solution to a cylindrical cavity exists (http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity), and it would be worthwhile to compare how far is the MEEP solution for a resonant cylindrical cavity, say of a diameter=Sqrt[BigDiameterOfTruncatedCone * SmallDiameterOfTruncatedCone]=0.21060 m and same axial length, with the same material inputs and mesh as used for the Finite Difference solution of the Truncated Cone.
....
I propose a MEEP analysis for a resonant cylindrical cavity (no dielectric), with diameter=Sqrt[BigDiameterOfTruncatedCone * SmallDiameterOfTruncatedCone] and same axial length=0.2286 m as the NASA cavity, with the same material inputs and mesh as you used for the Finite Difference solution of the Truncated Cone.
Actual geometry
Large OD : 11.00 " (0.2794m),
Small OD: 6.25" (0.1588 m)
Length : 9.00 " (0.2286m)
Geometric Mean Diameter: 0.2106056741875679 m
If the MEEP mesh for the truncated cone cannot be used to obtain a MEEP solution close to the exact solution for a cylindrical cavity of similar dimensions (an easier problem to solve than the truncated cone), then that mesh and solution (2D?) cannot get a reliable solution for the EM Drive truncated cone, concerning EM Drive for space flight applications. (The cylindrical cavity is an easier problem because the mode shapes are either purely resonating (real solutions) or evanescent (imaginary solutions) while for a truncated cone there are modes that go from resonating to evanescent, and because the truncated cone displays interesting attenuation and focusing properties).
....
As you must know, there are several more-or-less independent modules in meep. The core FDTD algorithm that we should be concerned about is not the same as the Harminv algorithm which determines resonance frequencies and as you know, is suspect, at least by me and Dr. Dominic and I think, yourself. Proving again that the Harminv module is suspect will not show anything one way or the other about the core FDTD algorithm or the Flux and Forces modules. ....
....Please tell us more when you have a chance about the <<self-accelerating Dirac wavepacket (which does conserve momentum)>> as conservation of momentum has been the biggest problem of the scientific media (Prof. Baez and Sean Carroll for example) and with the serious science-fiction media (Greg Egan) with the EMDrive. How does momentum get conserved in the EMDrive when there is nothing coming out of the EM Drive?
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
...
http://physics.stackexchange.com/questions/160702/self-accelerating-wavepackets-what-are-they-and-can-they-impulse-a-spaceship
http://www.nature.com/nphys/journal/vaop/ncurrent/fig_tab/nphys3196_F1.html
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
Or are you considering that evanescent waves coming out of the EM Drive in outer space (with no fields or matter nearby to interact with) are responsible for conservation of momentum with an effectiveness much greater than a photon rocket?
This is certainly interesting but there are no "specially engineered phase masks" in Emdrive.
Same people: http://arxiv.org/pdf/1205.2112.pdf
It has been recently argued that thehttp://arxiv-web3.library.cornell.edu/abs/0908.4390
quantum vacuum can possess momentum
This is a goldmine of information concerning non-reciprocal materials!
http://arxiv.org/abs/1211.0530
The visual is to help communicate the concept.
From the most basic concepts, I argue that yes the quantum vacuum can possess momentum.QuoteIt has been recently argued that the
quantum vacuum can possess momentum
I've tried to understand the totality of the emdrive mystery in a lot of different ways ranging from it being pure bs to some quirk with inertia. The only way it makes sense is to apply that "momentum from the qv" theory I've been going on about. It is the only one left that still passes the smell test and doesn't try and overturn established science. It seems like a perfect fit for the conditions and two unconnected teams of researchers make the same claims.
Most importantly, it makes falsifiable predictions.
I've tried to understand the totality of the emdrive mystery in a lot of different ways ranging from it being pure bs to some quirk with inertia. The only way it makes sense is to apply that "momentum from the qv" theory I've been going on about. It is the only one left that still passes the smell test and doesn't try and overturn established science. It seems like a perfect fit for the conditions and two unconnected teams of researchers make the same claims.
Most importantly, it makes falsifiable predictions.
Except that it *does* "try and overturn established science". Momentum from the quantum vacuum is not compatible with generally accepted physics.
Unconnected teams can easily be mislead by similar mistakes. Just look at how many independent observers claimed to see canals on the surface of Mars when they were on the edge of the signal/noise boundary of optical telescopes.
Well it has been accepted for publication at least.
http://iopscience.iop.org/0953-8984/page/Forthcoming%20articles#Special_isCasimir_fo
And the other citations are already published.
http://lpm2c.grenoble.cnrs.fr/spip.php?page=publications&id_auteur=18&clepubli=van%20Tiggelen&lang=fr
So we're not dealing with a crank here.
Folks:
While you all talk about various ways to accomplish the E&M simulations of these frustum cavities, I thought you might like to take a look at the COMSOL derived resonances of the Eagleworks Lab's copper frustum resonant cavity driven with a ~16mm OD loop antenna located 15% up the side wall of the frustum from the large OD end of the cavity.
BTW, the EMPower amplifiers were delivered to the Lab yesterday and I'll be calibrating the power metering for one that was installed yesterday on the torque pendulum.
Best, Paul M,
Ok, maybe I'm a bit slower than I ought to be lately, but are you guys telling us that they are, essentially, developing a propellentless thrust system based on a RADAR SYSTEM?
Ok, maybe I'm a bit slower than I ought to be lately, but are you guys telling us that they are, essentially, developing a propellentless thrust system based on a RADAR SYSTEM?
You never noticed that the ship rocks harder when the radars are turnin' and burnin'? Shoot, they should just sector SPY back aft and cut the engines. :-)
http://en.wikipedia.org/wiki/Arleigh_Burke-class_destroyer
Based on electromagnetic waves. Waveguide are found in numerous applications besides radars. Sorry back on topic...
Wasn't that how Shawyer got the idea, only from a satellite not a ship?
If I understood correctly some things in this thread, EM radiations heat the frustum, which changes its shape, which changes the resonant frequency of the cavity, so it's difficult to keep the EM source tuned.Cooling from the outside may actually be counterproductive, as it may increase the thermal gradient through the thickness (it would be induction-heated from the inside and cooled from the outside hence a large thermal gradient) and deform the very thin NASA EM Drive shell due to the non-uniform aspect of the induction heating due to the non-uniform EM field.
Would cooling (with flowing water for example) the copper plates 1) reduce the variation of the resonant frequency, by reducing the variation of temperature, thus reducing the geometrical changes of the frustum 2) not interfere with the thrust produced ?
If I understood correctly some things in this thread, EM radiations heat the frustum, which changes its shape, which changes the resonant frequency of the cavity, so it's difficult to keep the EM source tuned.Water cooling would either have to be internal to the thrust measuring device or external.
Would cooling (with flowing water for example) the copper plates 1) reduce the variation of the resonant frequency, by reducing the variation of temperature, thus reducing the geometrical changes of the frustum 2) not interfere with the thrust produced ?
Or a phase locked loop circuit.
http://en.m.wikipedia.org/wiki/Phase-locked_loop#Frequency_synthesis
Or a phase locked loop circuit.How would apply this to tracking the resonant freq of the cavity to the input freq of the loop antenna?
http://en.m.wikipedia.org/wiki/Phase-locked_loop#Frequency_synthesis
I also like Mulletron's original idea of distributing the spectral power density of the input into a spectral band instead of a spike at a single frequency. As Mulletron pointed out, magnetrons used by Juan Yang in China and Shawyer in the UK deserve attention.Or a phase locked loop circuit.How would apply this to tracking the resonant freq of the cavity to the input freq of the loop antenna?
http://en.m.wikipedia.org/wiki/Phase-locked_loop#Frequency_synthesis
A feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?
A feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?
I agree, the only way you could do it is to lock the thrust to the freq. How you would do that though to avoid false maxima is beyond me.A feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?
This is the problem :) I do understand controls and realtime systems but microwaves and resonant cavities are not my field. How do you know it is resonating?
In theory the thrust could be your feedback, you tune the VCO in order to maximize that.
Resonant cavities are also filters. You monitor a sample port to ensure the cavity is resonant at the desired frequency.It seems to me that it matters where you put the sample port with a truncated frustum.
Another control loop compensating for doppler drift is needed. Shawyer mentions this type of control loop over at emdrive.com.
I think we're getting on a tangent. But here's your answer.Not really, with respect.
http://www.radartutorial.eu/03.linetheory/tl11.en.html
A feedback circuit would be required in order to keep the VCO on the resonant frequency. If such a feedback is possible then a simple MCU could be programmed to do that using an ADC as output, it would not be a PLL anyway but more similar to an FLL.Where does the feedback signal come from?
This is the problem :) I do understand controls and realtime systems but microwaves and resonant cavities are not my field. How do you know it is resonating?
In theory the thrust could be your feedback, you tune the VCO in order to maximize that.
Higher thrust at lower Q seems to hint at heating/other reasons unfortunately...I agree, but still, using thrust as feedback is superior to relying on resonance at this stage of knowledge.
Dr. Rodal,Need you to elaborate further: false because...it is a local maximum and not the true maxima...false because of error...false because of lag...
What do you think about the false maxima that we could get in the thrust of the EM Drive?
Indeed! We need to get the computing resources together to help us...Dr. Rodal,Need you to elaborate further: false because...it is a local maximum and not the true maxima...false because of error...false because of lag...
What do you think about the false maxima that we could get in the thrust of the EM Drive?
Not really my expertise field, but can somebody tell me if the volumetric resonance patterns are static or dynamic?As far as I know the resonant freq. is very sensitive to the cavity properties.
iow, does the combination of internal frustrum shape and wavelength(s) cause the resonance pattern to shift left or right (Is that the "reverse" ppl were talking about?), or does it stay immobile (static) once the interference patterns are established ??
I understand that the shape and aspect of the resonance pattern is very very sensitive and can easily change aspect (and direction?) caused by the slightest change (either wavelength or geometry of the frustrum).
As some of you talked about dielectric materials possibly improving performance, I suppose a force could be generated from the high intensity microwave resonance spots colliding with the frustrum? Am I correct on this assumption?
If that is the case, and looking at it from a distance, shouldn't we speak of a "magnetic pulse engine" as the high-intesity magnetic fields slam into frustrum wall, pushing it forward ?
or.. am i talking completely BS here? :)
Just trying to understand while feeling very much out of comfort zone...
we have found that the chiral molecule acquires a kinetichttp://arxiv.org/pdf/1404.5990v1.pdf
momentum during the switching of the external magnetic field as a result of its
interaction with the vacuum field. On the other hand we have shown that, as a
result of the conservation of the total momentum K, there exists a transfer of linear
momentum from the vacuum field to the molecule.
Moreover, the same effect is expected in quantum vacuum.
Strong H field at dielectric disc. Just like theory suggests.Quotewe have found that the chiral molecule acquires a kinetichttp://arxiv.org/pdf/1404.5990v1.pdf
momentum during the switching of the external magnetic field as a result of its
interaction with the vacuum field. On the other hand we have shown that, as a
result of the conservation of the total momentum K, there exists a transfer of linear
momentum from the vacuum field to the molecule.
http://arxiv.org/abs/1304.6767
But it isn't JUST chiral molecules, as I've shown experimental evidence of the observation of magneto-electric non-reciprocity in molecular nitrogen gas.
https://hal.archives-ouvertes.fr/hal-00551421v1/document
http://arxiv.org/abs/1101.0712
Which means that air confined to a resonant cavity falls into their magneto-electric metric too. Any condition which creates a chiral electromagnetic vacuum environment works.
Which explains why unloaded cavities tested by the Chinese and Shawyer work too.
This implies that a magneto-electric directionally anisotropic electromagnetic environment also absolutely implies an anisotropic vacuum environment, as the authors suggest is true and aim to measure.QuoteMoreover, the same effect is expected in quantum vacuum.
Only I found evidence last night that the vacuum anisotropy experiment has already been done in the 80s.
http://heart-c704.uibk.ac.at/LV/Quantenoptik/Kapitel_8/Jhe_etal_PRL_58_666_%281987%29.pdf
This Emdrive operates exactly as I have suggested and existing theory supports. I've beat this dead horse enough.
Folks:
While you all talk about various ways to accomplish the E&M simulations of these frustum cavities, I thought you might like to take a look at the COMSOL derived resonances of the Eagleworks Lab's copper frustum resonant cavity driven with a ~16mm OD loop antenna located 15% up the side wall of the frustum from the large OD end of the cavity.
BTW, the EMPower amplifiers were delivered to the Lab yesterday and I'll be calibrating the power metering for one that was installed yesterday on the torque pendulum.
Best, Paul M,
@ RODAL(Almost) anything is possible if I get the time :)
Can you generate a dispersion relation from the exact solution ?
@ RODAL(Almost) anything is possible if I get the time :)
Can you generate a dispersion relation from the exact solution ?
This work done whenever I take a break from $$$ paying work :)
It continues to snow over here ;)
@ RODAL@NotSoSureOfIt
Can you generate a dispersion relation from the exact solution ?
@ RODAL@NotSoSureOfIt
Can you generate a dispersion relation from the exact solution ?
I think that the relation between the wavenumber k and the angular frequency omega is perfectly linear for a truncated cone homogeneously filled with a medium having constant, isotropic, electric permittivity and constant magnetic permeability. It follows from the homogeneous electromagnetic wave equation, which for the truncated cone is solved in spherical coordinates via spherical waves (this involves an assumption of spherical ends, instead of flat ends).
Is your question what is the effective dispersion relation for a truncated cavity containing a dielectric (with constant properties) filling only a portion of the truncated cone?
Or is your question what is the dispersion relation for a truncated cavity containing a dielectric with nonlinear properties? Or anisotropic properties?
Or am I wrong, or missing something, ...
@ RODAL@NotSoSureOfIt
Can you generate a dispersion relation from the exact solution ?
I think that the relation between the wavenumber k and the angular frequency omega is perfectly linear for a truncated cone homogeneously filled with a medium having constant, isotropic, electric permittivity and constant magnetic permeability. It follows from the homogeneous electromagnetic wave equation, which for the truncated cone is solved in spherical coordinates via spherical waves (this involves an assumption of spherical ends, instead of flat ends).
Is your question what is the effective dispersion relation for a truncated cavity containing a dielectric (with constant properties) filling only a portion of the truncated cone?
Or is your question what is the dispersion relation for a truncated cavity containing a dielectric with nonlinear properties? Or anisotropic properties?
Or am I wrong, or missing something, ...
I was just thinking of the simplest case but based on your exact solution, rather than using that of the cylindrical cavity evaluated at both ends, which is what I have been using. The radii of both ends would presumably be already present in the single (presumably quadratic ?) expression.
Mmmm...I see the problem.
Folks:
While you all talk about various ways to accomplish the E&M simulations of these frustum cavities, I thought you might like to take a look at the COMSOL derived resonances of the Eagleworks Lab's copper frustum resonant cavity driven with a ~16mm OD loop antenna located 15% up the side wall of the frustum from the large OD end of the cavity.
BTW, the EMPower amplifiers were delivered to the Lab yesterday and I'll be calibrating the power metering for one that was installed yesterday on the torque pendulum.
Best, Paul M,
Thank you, Paul, for posting this, the attached pdf with COMSOL plots (which I first missed, my bad, thanks to Mulletron for pointing it out to me :) ) is very useful for all of us (those like me working on the exact solution of the frustum, and those working with numerical methods like MEEP, COMSOL, ANSYS-multiphysics, etc.).
I could not find in the pdf attached to your post, or in your post. language to indicate whether the COMSOL calculations in the attachment (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=796287) include or do not include a dielectric inside the truncated cone (frustum). My impression is that these COMSOL calculations do not include the dielectric inside the truncated cone (this impression is based on the frequency calculated for TE012).
Still a clarification for some readers like me, may be useful (to those to whom what I write below is obvious, please forgive me for taking your time):
1) Clarification: the jpg image you posted are not "COMSOL derived resonances of the Eagleworks Lab's copper frustum resonant cavity", the COMSOL plots are in the pdf attached to your post (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=796287)
2) The mode shapes in the slide are for a different geometry: a circular waveguide (instead of a truncated cone/frustum like NASA's EM Drive) , that had been plotted in published journals since 1936, without using a digital computer. The actual reference's date is 1985 (instead of 1966): http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1132998. Since COMSOL was started in 1986, Lee, Lee and Chuang did not use COMSOL: they had no need to use a finite element program, because an exact solution exists for what they plotted: the mode shapes of a circular waveguide.
The circular waveguide exact solution is present in the 1943 textbook by Schelkunoff, and in papers he published in the 1930's. The mode shapes look identical to the plots that Schelkunoff published in the 1930's without the benefit of a digital computer: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332981#msg1332981. The article by Lee, Lee and Chuang states: "The earliest plots of modal field distribution in rectangular/circular waveguides were given by Southworth (1936), Barrow (1936), Schelkunoff (1937), and Chu and Barrow (1937)"
3) The solution for a truncated cone (the geometry of the NASA frustum, and the geometry analyzed by COMSOL in the attached pdf) is different from the solution for a circular waveguide in several respects: the natural frequencies are quite different, and while in a circular waveguide different mode shapes are either resonant or cutoff, in a truncated cone some mode shapes are resonant, some are evanescent and some have a transition from resonant to evanescent (a characteristic not present in circular waveguides). Also, the attenuation and focusing aspects of the truncated cone (frustum) are not present in the circular waveguide.
Symetry violations are hot topics in physic since decades.Strong H field at dielectric disc. Just like theory suggests.
Wow. Those are quite remarkable papers. It seems like a very likely cause for the thrust, with previous published results availing it.
I wonder why the research wasn't pursued to its logical conclusion (a thruster). Maybe the researchers didn't believe they could get usable forces?
Well this is a gut check moment and there is no doubt this post will be controversial and might get me in trouble for being off topic and for the subject matter. I am being serious here. I'm no dummy. Either we didn't figure out jack or we actually did. It seems very likely that we did. If we did, we weren't the first.
We all know how the world works. If a bunch of guys on an internet forum can figure out the basic principles of "q-thrusters".... someone else has already perfected them and kept them black; rightfully so. The cat is now out of the bag gentlemen. We want to explore space. I want to see human space missions to the planets. We all do. Please give what you have to the world.
This isn't tin foil hat wearing nonsense. NOT UFO conspiracy theory bs. It is no different than this:
http://www.aviationweek.com/technology/skunk-works-reveals-compact-fusion-reactor-details
http://en.wikipedia.org/wiki/Skunk_Works
#giveusthegoods
Sorry moderators. This won't happen again. I don't want the thread to devolve into this kind of discussion. I am pointing out the obvious. I'll delete the post if asked to do so.
FYI(http://cosmic-fitness.com/wp-content/uploads/2013/09/go-for-it.jpg)
https://www.dropbox.com/s/xiw9mq7dawhp00c/other1.jpg?dl=0
What I would really like to do is stack these 2 puppies on the left into a single vertical chamber and try the Cavandish type experiment under battery power w/ a solid-state oscillator.
OK, couldn't get the pic to post but the link works ... so that would be my retirement plan (fat chance)
A little less fantasy;
https://www.dropbox.com/s/cxfcrf822n0dpsa/IMAG0359.jpg?dl=0
I'm (slowly) collecting parts for an X-band miniature version in the cans shown in the middle of the picture.
Higher frequency and lower power. (we have a lot of experience w/ battery power in vacuum and/or plasma)
Anybody have a short taper section from X to something smaller ?
(https://www.dropbox.com/s/cxfcrf822n0dpsa/IMAG0359.jpg?dl=0)
?? can't get pics to post directly .. must be the Alzhiemers !
EDIT: Apparently the problem is with the way that Dropbox posts the image in a webpage: the dropbox link does not show like other linksIt is probably simplest to do as elsewhere on the forum: attach/upload the pictures directly. Especially now that the effort has probably snowballed for good.
Isn't frustum a misnomer since frustum refers to a cone, not a four-sided structure...?Welcome to this thread.
Is the frustum-under-test (fut) just a truncated pyramid structure?
...
...The thrust of the EM Drive (if it is not an artifact, and if indeed it can be used for space propulsion) it is not expected to scale geometrically. On the contrary, (as discussed previously in this thread), the larger the diameter, the lower the natural frequencies of the first few modes. A significantly larger EM Drive truncated cone would result in either very low natural frequencies for the first few modes, or if one would attempt to excite the EM Drive in the GHz range, these natural frequencies would correspond to very high mode shapes that would be bunched up together in the frequency spectrum and it would be even much more difficult to keep the EM Drive in resonance with a particular mode shape. Also, very high natural frequency mode shapes are extremely difficult to calculate accurately (even with the exact solution, and almost hopeless with the Finite Element method because of difficult issues associated with ill-conditioning in inverting the matrix for very large eigenvalues).
If the a frustum produces 100 mN thrust,
a Giza size structure might produce thrust of 100 million Newtons.
In comparison, a Saturn V First stage
produces approximately 34 kN (7,648,000 lbf)
If we scale up by a only a factor of 10 or 100,
we have respectively thrust maximums of 100 N or 100 kN.
...
Not really my expertise field.............Welcome to the group. This is very much a multidisciplinary effort. What are you good at?
FYIDoes it work by work by electrically expelling propellant (reaction mass) at high speed?
http://www.intelligent-aerospace.com/articles/2015/02/boeing-to-build-all-electric-propulsion-satellite-for-ses.html
...The thrust of the EM Drive (if it is not an artifact, and if indeed it can be used for space propulsion) it is not expected to scale geometrically. On the contrary, (as discussed previously in this thread), the larger the diameter, the lower the natural frequencies of the first few modes. A significantly larger EM Drive truncated cone would result in either very low natural frequencies for the first few modes, or if one would attempt to excite the EM Drive in the GHz range, these natural frequencies would correspond to very high mode shapes that would be bunched up together in the frequency spectrum and it would be even much more difficult to keep the EM Drive in resonance with a particular mode shape. Also, very high natural frequency mode shapes are extremely difficult to calculate accurately (even with the exact solution, and almost hopeless with the Finite Element method because of difficult issues associated with ill-conditioning in inverting the matrix for very large eigenvalues).
If the a frustum produces 100 mN thrust,
a Giza size structure might produce thrust of 100 million Newtons.
In comparison, a Saturn V First stage
produces approximately 34 kN (7,648,000 lbf)
If we scale up by a only a factor of 10 or 100,
we have respectively thrust maximums of 100 N or 100 kN.
...
What is envisioned (if it is not an artifact, and if indeed it can be used for space propulsion) , rather than a very large EM Drive, is to maximize the thrust of the EM Drive (perhaps using superconductivity, and/or high magnetic permeability materials for the big flat end, as well as much better, anisotropic, dielectric) and to use a number of EM Drives to achieve a large overall thrust.
Unlike liquid propellant rocket engines, there are no issues of fuels and oxidizers hydraulic lines, pumps, injectors, combustion instability, ignition, hydraulic pressure, etc., associated with using a large number of EM Drives, of course, particularly if ambient temperature EM Drives are used (and superconducting low temperature solutions are avoided).
FYIDoes it work by work by electrically expelling propellant (reaction mass) at high speed?
http://www.intelligent-aerospace.com/articles/2015/02/boeing-to-build-all-electric-propulsion-satellite-for-ses.html
http://spacenews.com/35894electric-propulsion-satellites-are-all-the-rage/
.
The thrust of the EM Drive (if it is not an artifact, and if indeed it can be used for space propulsion) it is not expected to scale geometrically. On the contrary, (as discussed previously in this thread), the larger the diameter, the lower the natural frequencies of the first few modes. A significantly larger EM Drive truncated cone would result in either very low natural frequencies for the first few modes, or if one would attempt to excite the EM Drive in the GHz range, these natural frequencies would correspond to very high mode shapes that would be bunched up together in the frequency spectrum and it would be even much more difficult to keep the EM Drive in resonance with a particular mode shape. Also, very high natural frequency mode shapes are extremely difficult to calculate accurately (even with the exact solution, and almost hopeless with the Finite Element method because of difficult issues associated with ill-conditioning in inverting the matrix for very large eigenvalues).
What is envisioned (if it is not an artifact, and if indeed it can be used for space propulsion) , rather than a very large EM Drive, is to maximize the thrust of the EM Drive (perhaps using superconductivity, and/or high magnetic permeability materials for the big flat end, as well as much better, anisotropic, dielectric) and to use a number of EM Drives to achieve a large overall thrust.
Unlike liquid propellant rocket engines, there are no issues of fuels and oxidizers hydraulic lines, pumps, injectors, combustion instability, ignition, hydraulic pressure, etc., associated with using a large number of EM Drives, of course, particularly if ambient temperature EM Drives are used (and superconducting low temperature solutions are avoided).
Hi,
Just want to say that I am enjoying this thread immensely even though a lot of the science is a bit above my pay grade!
If the thrust is not an artifact of the experiment, in theory what level of thrust are we expecting in the best circumstances?
This is what confusing about this as some proponents of the technology talk of grand projects others speak of far more modest expectations and to the layperson that's rather confusing.
This is what confusing about this as some proponents of the technology talk of grand projects others speak of far more modest expectations and to the layperson that's rather confusing.
This is what confusing about this as some proponents of the technology talk of grand projects others speak of far more modest expectations and to the layperson that's rather confusing.
I would think that the larger, more optimistic predictions are relying on technology that hasn't been developed yet but is in theory possible.
This is what confusing about this as some proponents of the technology talk of grand projects others speak of far more modest expectations and to the layperson that's rather confusing.
I would think that the larger, more optimistic predictions are relying on technology that hasn't been developed yet but is in theory possible.
Good point. The other point of confusion is this purely a technology if it works that is only useful outside the atmosphere because of the conditions of its operation. I've read it couldn't actual get anything on its own off the ground, so it's of no use for a making a launch vehicle. We aren't going to get George Jetson getting in his flying car and nipping off to the moon.
A question... is the Q-Thruster that was being worked by EagleWorks Lab similar to the EM Drive they tested? Are them completely different things with different principles? I have the vague notion of seeing a photo of it long ago (while the main subject of the article was in fact Dr White's Warp Drive experiments) and I don´t remember it having a cone similar to Shawyer's EM Drive, so I guess they are totally different principles? I wonder if the former is still being pursued? If it is "considered" an EM Drive? Maybe Paul March can clear this up (if noone else knows the answer)?
Would one practical use, if they do work, be a satellite with clusters of EM drives on different axis used for station keeping?
Of how much practical use would they be in reality for interplanetary probes.
A question... is the Q-Thruster that was being worked by EagleWorks Lab similar to the EM Drive they tested? Are them completely different things with different principles? I have the vague notion of seeing a photo of it long ago (while the main subject of the article was in fact Dr White's Warp Drive experiments) and I don´t remember it having a cone similar to Shawyer's EM Drive, so I guess they are totally different principles? I wonder if the former is still being pursued? If it is "considered" an EM Drive? Maybe Paul March can clear this up (if noone else knows the answer)?
It appears that when METs, MLT, SFEs, Cannaes and Emdrives go through the doors of Eagleworks, they get rolled into the QVPT conjecture. In reality, they come from different sources, different inventors with different theories of operation. Dr. White, IMHO is right to try and unify these different types of "thrusters" under the same paradigm. I think they are all unified too under the same interaction, maybe not QVPT per se, but they share the QV as a common means of interaction.
https://www.linkedin.com/pub/hector-serrano/29/69b/9a5
https://xa.yimg.com/kq/groups/86787010/513081407/name/Eagleworks+Newsletter+2013.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140009930.pdf
Shawyer has seemed convinced that this drive is able to replace commercial airliner engines etc. Obviously as he is the main proponent of the drive so this might be taken with a pinch of salt or two but if the drive is proven to be real he definitely seems to be ahead of the curve with the technology.
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSeF0z098aKsq-NFkxYS7IypVicisG8IM3AiidTeKKRbh8RFIT1B1y5Ju3J)
FYI
http://www.intelligent-aerospace.com/articles/2015/02/boeing-to-build-all-electric-propulsion-satellite-for-ses.html
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSeF0z098aKsq-NFkxYS7IypVicisG8IM3AiidTeKKRbh8RFIT1B1y5Ju3J)
The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSeF0z098aKsq-NFkxYS7IypVicisG8IM3AiidTeKKRbh8RFIT1B1y5Ju3J)
The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.
That was odd stuff, I wonder if it can make a resonant circuit that way?
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSeF0z098aKsq-NFkxYS7IypVicisG8IM3AiidTeKKRbh8RFIT1B1y5Ju3J)
The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.
That was odd stuff, I wonder if it can make a resonant circuit that way?
I agree, that's why I wrote "It can be represented by a simple LC circuit only". Yes, with a circuit complicated enough we could probably simulate most electromagnetic wave phenomena, just like the few analog computers that still were being used at MIT Draper Labs in the early 1970's to solve differential equations. I remember those :). Reconfiguring the analog computer to solve a different equation required actual handwork unlike just writing software for digital computers :-)
It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.
That was odd stuff, I wonder if it can make a resonant circuit that way?
I agree, that's why I wrote "It can be represented by a simple LC circuit only". Yes, with a circuit complicated enough we could probably simulate most electromagnetic wave phenomena, just like the few analog computers that still were being used at MIT Draper Labs in the early 1970's to solve differential equations. I remember those :). Reconfiguring the analog computer to solve a different equation required actual handwork unlike just writing software for digital computers :-)
I guess I can't stop thinking about the 1/ f^3 in the thrust equation.
Dual 12at7's I think....
...
I guess I can't stop thinking about the 1/ f^3 in the thrust equation.
Dual 12at7's I think....
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
...
I guess I can't stop thinking about the 1/ f^3 in the thrust equation.
Dual 12at7's I think....
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the thrust really decreases as the cube of the frequency...wouldn't you get much less thrust operating your experiment in the X band? ( 8.0 to 12.0 GHz instead of 2 GHz implies 64 to 216 times less thrust, of course that's with everything else being the same which is not going to be...)
...
I guess I can't stop thinking about the 1/ f^3 in the thrust equation.
Dual 12at7's I think....
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the thrust really decreases as the cube of the frequency...wouldn't you get much less thrust operating your experiment in the X band? ( 8.0 to 12.0 GHz instead of 2 GHz implies 64 to 216 times less thrust, of course that's with everything else being the same which is not going to be...)
L goes down as well, but then the x-band sources are usually not as efficient either. How much more sensitive is the Cavendish setup?
Well, mmm... of formation, I'm an architect, but always had a strong interest in what happening on the nuclear science field and spaceflight development. But the last 25 years I've specialized in 3D visualizations, 3Dmodeling and 3Dprinting (8 years).Not really my expertise field.............Welcome to the group. This is very much a multidisciplinary effort. What are you good at?
Great :), we needed (and we still need) help with estimating dimensions of test articles from photographs that often have parallax problems and undimensioned drawings (technical authors often fail to detail the dimensions in their technical papers). We are very fortunate that Paul March was kind enough to supply the dimensions of the NASA EM Drive truncated cone, but we will need help to estimate other devices from the UK, China and the USA. Still @aero and @Mulletron did a fantastic job in estimating the NASA EM Drive dimensions just from the photographs.Well, mmm... of formation, I'm an architect, but always had a strong interest in what happening on the nuclear science field and spaceflight development. But the last 25 years I've specialized in 3D visualizations, 3Dmodeling and 3Dprinting (8 years).Not really my expertise field.............Welcome to the group. This is very much a multidisciplinary effort. What are you good at?
I fear that on the real hard science level, i might have little to nothing to add to the high standards here, but if there is anything I can do as far as visual communication goes, I might be of help or assistance, if needed...
I also have considerable experience modeling for and working with a powder 3Dprinter, but I suppose NASA has much more advanced systems to their disposal.
And ofc, If any of the DIY builders here would require assistance in building 3Dmodels for 3dprinting i'll gladly assist.
Shawyer has seemed convinced that this drive is able to replace commercial airliner engines etc. Obviously as he is the main proponent of the drive so this might be taken with a pinch of salt or two but if the drive is proven to be real he definitely seems to be ahead of the curve with the technology.
...
Shawyer has yet to prove that the performance of his "engine" scales linear with a dramatically increased Q.
..
...
Shawyer has yet to prove that the performance of his "engine" scales linear with a dramatically increased Q.
..
Good point, on the other hand all theoretical formulas so far scale linearly with Q:
@Notsosureoit: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332746#msg1332746
....
...
Shawyer has yet to prove that the performance of his "engine" scales linear with a dramatically increased Q.
..
Good point, on the other hand all theoretical formulas so far scale linearly with Q:
@Notsosureoit: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332746#msg1332746
....
I keep checking back and ..... there's another bloody typo ! N=P*Q/(2*pi*h*f^2) [ f^2 NOT f ]
If I could type I'd be dangerous !
Going back and scaling term by term it looks like (at constant power) only Q and X, everything else is a wash between distances and freq.
those mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times.
S8G weight 2750 tons?those mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times.
Aceshigh:
When it comes to manned solar electric propulsion missions, the largest to date proposed photovoltaic arrays for a human crewed missions are in the 300 kilowatt electric (kW-e) power range. However most of the Q-Thruster solar system based mission analysis we did last year assumed using a U235 fission based reactor with a closed-cycle brayton or rankine thermal to electrical power conversion cycle system in the 1.0-to-2.0 Megawatt electric (MW-e) class output with at least a 10 year lifetime. Now it's true that such a space based nuclear power reactor system has never been fielded, but that was due to a lack of a funded mission for same like sending humans to Mars, but more importantly, the lack of the political will to do so. However building such a space-based closed cycle electrical power reactor is technologically feasible and has been since the 1980s.
Now like all naval propulsion system, once you've established the viability of a propulsion technique like the EM-Drive, and have an urgent need to do so, what comes next is developing the long lead items needed to power it. And all these electric space propulsion concepts for deep-space human missions, be they conventional ion, Hall or VASMIR type plasma rocket thrusters, or Q-thruster like space drives, go begging for an already developed nuclear power plant that is sized from 1.0 MWe up to 100 MWe output dependent on the mission scenario. I know that this sounds like a lot of power to the space community, but when it's compared to what the US Navy already builds for its nuclear submarine fleet like its "Boomer' Ohio class ICBM vehicles, which sport the 220 MW-thermal (MW-t) S8G reactor that fits in a 42 foot diameter by 55 feet long container and lasts for up to 30 years between refueling, its not a lot to ask technically if we just had the real need to do so. And that will always be a political and business decision, not a technical one.
Best, Paul M.
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity.
(https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSeF0z098aKsq-NFkxYS7IypVicisG8IM3AiidTeKKRbh8RFIT1B1y5Ju3J)
The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.
That was odd stuff, I wonder if it can make a resonant circuit that way?
I agree, that's why I wrote "It can be represented by a simple LC circuit only". Yes, with a circuit complicated enough we could probably simulate most electromagnetic wave phenomena, just like the few analog computers that still were being used at MIT Labs in the early 1970's to solve differential equations. I remember those :). Reconfiguring the analog computer to solve a different equation required actual handwork unlike just writing software for digital computers :-)
those mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times.
Aceshigh:
When it comes to manned solar electric propulsion missions, the largest to date proposed photovoltaic arrays for a human crewed missions are in the 300 kilowatt electric (kW-e) power range. However most of the Q-Thruster solar system based mission analysis we did last year assumed using a U235 fission based reactor with a closed-cycle brayton or rankine thermal to electrical power conversion cycle system in the 1.0-to-2.0 Megawatt electric (MW-e) class output with at least a 10 year lifetime. Now it's true that such a space based nuclear power reactor system has never been fielded, but that was due to a lack of a funded mission for same like sending humans to Mars, but more importantly, the lack of the political will to do so. However building such a space-based closed cycle electrical power reactor is technologically feasible and has been since the 1980s.
Now like all naval propulsion system, once you've established the viability of a propulsion technique like the EM-Drive, and have an urgent need to do so, what comes next is developing the long lead items needed to power it. And all these electric space propulsion concepts for deep-space human missions, be they conventional ion, Hall or VASMIR type plasma rocket thrusters, or Q-thruster like space drives, go begging for an already developed nuclear power plant that is sized from 1.0 MWe up to 100 MWe output dependent on the mission scenario. I know that this sounds like a lot of power to the space community, but when it's compared to what the US Navy already builds for its nuclear submarine fleet like its "Boomer' Ohio class ICBM vehicles, which sport the 220 MW-thermal (MW-t) S8G reactor that fits in a 42 foot diameter by 55 feet long container and lasts for up to 30 years between refueling, its not a lot to ask technically if we just had the real need to do so. And that will always be a political and business decision, not a technical one.
Best, Paul M.
I wonder if the cavity itself could be used as part of the oscillator using a Gunn diode: http://en.wikipedia.org/wiki/Gunn_diode
The resulting device would be incredibly compact and self contained, tuning would be inherently a non-issue.
...
But unlike all the conventional electric space propulsion concepts(1) propellantless schemes have a potential for practical unlimited power generation as soon as around tpr = 1N/kWe is proven, by mounting driver(s) on a rotor linked to a generator of efficiency n and having a tangential speed above 1/(n * tpr). See attached picture.
The only caveat I see would be if wakes of successive passages at same place would interfere and lower the effective thrust power ratio below over-unit cycle. Even in this case I don't see how an over-unit power generating system would still be impossible : use a larger rotor (tethered... many km apart if needed) to give more time for hypothetical wakes to dissipate, use a linear scheme...
So, assuming better than 1N/kW can be reached, why bother with conventional energy generators ? Because we would want to convince ourselves that this is not breaking energy conservation and avoid the "free energy" tag ? But it is not "worse" to posit apparent cheap energy than to posit apparent cheap momentum, and from an engineering point of view it makes no sense to use the later and refusing to see the possibility to use the former.
Sorry, this is a repost, for details : http://forum.nasaspaceflight.com/index.php?topic=29276.msg1284676#msg1284676 (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1284676#msg1284676)
(1) except electrodynamic tether used as generator, but at the cost of absorbed deltaV : that is a 0 sum game...
I think this explains how Emdrive can never go over unity.
http://usersguidetotheuniverse.com/?p=2865
In the case of the EM Drive, to answer the "overunity" question one has to perform a complete analysis of the whole system. This cannot be done in isolation, without a theory of operation for the EM Drive. It would be like arguing that a windmill or a sailing boat cannot move (in an analysis ignoring the wind) because it would be a source of practical unlimited power. Same thing with extracting energy from the ocean. In the case of the EM Drive, due consideration of the total system is required: whether coupling with the Quantum Vacuum, or coupling with any other external field.
In the case of the EM Drive, to answer the "overunity" question one has to perform a complete analysis of the whole system. This cannot be done in isolation, without a theory of operation for the EM Drive. It would be like arguing that a windmill or a sailing boat cannot move (in an analysis ignoring the wind) because it would be a source of practical unlimited power. Same thing with extracting energy from the ocean. In the case of the EM Drive, due consideration of the total system is required: whether coupling with the Quantum Vacuum, or coupling with any other external field.
Exactly, so we can't rule out the possibility of apparent energy overunity before (the reality of the effect is proven beyond any doubt and) there is a working theory than can encompass the "total system". But the point is, even before we have such working theory that would show how both energy and momentum conservation are guaranteed, we have an experimental/phenomenological prediction of a given thrust/power in a (Lorentz invariant) vacuum, if this is to hold for propulsion (and giving a ship more kinetic energy than spent electric power) then this is to hold for energy generation, regardless of the deeper theories.
I don't mean to sound insistent, but I feel a lot of resistance about that important empirical fact, more for psychological reasons than real scientific logic.
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work."Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
S8G weight 2750 tons?those mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times.
Aceshigh:
When it comes to manned solar electric propulsion missions, the largest to date proposed photovoltaic arrays for a human crewed missions are in the 300 kilowatt electric (kW-e) power range. However most of the Q-Thruster solar system based mission analysis we did last year assumed using a U235 fission based reactor with a closed-cycle brayton or rankine thermal to electrical power conversion cycle system in the 1.0-to-2.0 Megawatt electric (MW-e) class output with at least a 10 year lifetime. Now it's true that such a space based nuclear power reactor system has never been fielded, but that was due to a lack of a funded mission for same like sending humans to Mars, but more importantly, the lack of the political will to do so. However building such a space-based closed cycle electrical power reactor is technologically feasible and has been since the 1980s.
Now like all naval propulsion system, once you've established the viability of a propulsion technique like the EM-Drive, and have an urgent need to do so, what comes next is developing the long lead items needed to power it. And all these electric space propulsion concepts for deep-space human missions, be they conventional ion, Hall or VASMIR type plasma rocket thrusters, or Q-thruster like space drives, go begging for an already developed nuclear power plant that is sized from 1.0 MWe up to 100 MWe output dependent on the mission scenario. I know that this sounds like a lot of power to the space community, but when it's compared to what the US Navy already builds for its nuclear submarine fleet like its "Boomer' Ohio class ICBM vehicles, which sport the 220 MW-thermal (MW-t) S8G reactor that fits in a 42 foot diameter by 55 feet long container and lasts for up to 30 years between refueling, its not a lot to ask technically if we just had the real need to do so. And that will always be a political and business decision, not a technical one.
Best, Paul M.
BiiiiiiiiiiiigFR needed.
Ok,
For those of us who have become completely lost in the math, can you, in layman's terms, explain what everyone seems to SUSPECT is going on when it comes to converting electrical current into motive force?
I've tried to follow the math, but was lost a while back, and the best I can understand is that somehow it involves Vaccume Energy and possibley Dark Matter
Ok,
For those of us who have become completely lost in the math, can you, in layman's terms, explain what everyone seems to SUSPECT is going on when it comes to converting electrical current into motive force?
I've tried to follow the math, but was lost a while back, and the best I can understand is that somehow it involves Vaccume Energy and possibley Dark Matter
Much of the work in this thread has not been focused on theories of operation. Most of the recent math has been focused on attempts to amplify the observed effect, for the sake of demonstrating that it is a real effect, rather than experimental artifact.
There is not a consensus on the cause of the apparent thrust, be it real or imaginary. Suggestions for causes of real thrust include interactions with dark matter, harnessing linear momentum from the quantum vacuum, evanescent waves creating inertial moments, tapping into photons being the source of momentum in the universe in general... there's a lot of ideas out there. What all of these theories are short on is experimental data. Because there is no money (Eagleworks is not allowed to accept crowd funding), right now is the time to think. :P
Assuming that the EM Drive effectively work, it means you are somehow "stealing" energy from somewhere, and that you can create something which looks like perpetual motion. Let's say that the "somewhere" is the quantum void (QV). Since it can't have an infinite energy, it must mean that you can somehow deplete QV energy.
I'm not a specialist, but I think the question "What is the value of the vacuum energy of free space?" becomes relevant here. Additionally it raises disturbing (for me at least) questions, like "What happens when QV energy is depleted?".
I don't think you are looking at it correctly. Are you stealing from the earth's gravity when you do a push-up? Of course not.
Quote from: Von NeumannThe sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work."Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
The key take away from the light in a box page was the red shift/blue shift. The same thing is presented by Shawyer. Also the theory paper presented (see Colbert) explains precisely how momentum is conserved. There is no free/cheap momentum.
Asserting there are conservation issues /while at the same time not understanding the interaction doesn't make sense. That's like passing legislation governing the use of time travel and warp drive before they become real. Just speculation.
You just have to read the paper.
I think this explains how Emdrive can never go over unity.
http://usersguidetotheuniverse.com/?p=2865
The key take away from the light in a box page was the red shift/blue shift. The same thing is presented by Shawyer. Also the theory paper presented (see Colbert) explains precisely how momentum is conserved. There is no free/cheap momentum.
Asserting there are conservation issues /while at the same time not understanding the interaction doesn't make sense. That's like passing legislation governing the use of time travel and warp drive before they become real. Just speculation.
You just have to read the paper.
What paper ? Colbert ? Where ?
Not trying to be obtuse here but you'll have to connect the dots for me (and for some other readers I guess)... still not understanding how this is supposed to make an energy generating scheme to fail (under the assumption that an emdrive could give 1N of thrust when fed 1kW microwave power for instance).
Some doppler shift is supposed to modifie the thrust/power ratio when emdrive is accelerated ? Does it pertain to accelerations vectors orthogonal to the axis of the frustum (as would be the case for a frustum mounted on a flywheel) ? Does it pertain to arbitrarily low accelerations (as the proposed device would work at, say, fixed tangential velocity V=2 km/s, acc=V²/R so by extending the radius, radial acceleration can be made arbitrarily low) ? Does it pertain to an emdrive that is not accelerating, that is on straight trajectory, at constant velocity and thrusting at constant force that is pulling a tether that is rotating an electric generator ?
I'm not saying there is conservation issue, I'm concerned about consistency of a phenomenological model that's implied when mission profiles are proposed, this model is very simple : at a given microwave power there is a given thrust. Thrust=f(Power). Not Thrust=f(Power, Velocity wrt?, Acceleration, ...?) Granted, this model is speculative, but within this speculation it is not a speculation to state that the same effect used to accelerate a spacecraft can be used in a system that generates energy. It is not logical to operate under this assumption to devise mission profiles and not to devise unlimited energy generators.
From your previous remark :I think this explains how Emdrive can never go over unity.
http://usersguidetotheuniverse.com/?p=2865
So you seem to think that "Emdrive can never go over unity", isn't it a bit speculative at this stage ? Regardless of why, that would imply that you consider that the Emdrive can't be used to accelerate a spacecraft at constant thrust/power ratio. What would be the proposed Thrust=f(Power, Velocity wrt?, Acceleration, ...?)
To be clear, I'm not trying to make a case that emdrive makes apparent energy conservation breaking and that therefore it must be bogus. If the effect is bogus or not is decided by experience, not by armchair physicists. But armchair physicist is legitimate to foretell that if effect is not bogus for space flight application (thrusting for deltaV) then it is not bogus for energy generation : the two situations can be made undistinguishable from the point of view of the device. This is a package. Take both or leave both. Otherwise makes the claims appear not serious. Just saying.
For the later (energy generation) limitation on material makes the idea practical around 1N/kW above 1km/s speed (wrt local energy harvesting frame). So maybe the effect proves possible but not at such levels and that "prevents" the practical energy generation potential of the package. But even 50µN/50W is already enough to apparently break energy conservation, if not practically, at least in some physically possible setup.
“The law that entropy always increases, holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations—then so much the worse for Maxwell's equations. If it is found to be contradicted by observation—well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics, I can give you no hope; there is nothing for it but to collapse in deepest humiliation.” Sir Arthur Eddington (The Nature of the Physical World, 1915)http://web.mit.edu/keenansymposium/overview/background/
What is the end goal of this line of reasoning?
Does the model presented with the mission profile, potentially lead to a situation where the EmDrive could be used as an over Unity power generator? Maybe.
But lets for arguments sake agree that it does. What use is this information?
I ask this question because if anything is clear from the discussions in this thread and the reported results to date. We only have a few rough guestimates at what is going on within the EmDrive. To prove or disprove the over unity power generation assertion you would need to completely characterize everything that is going on in the system. Right now the most we know is that when we pump EM into the cavity we get some thrust. We don't know beyond a reasonable doubt where the thrust is actually coming from. We don't know what we are actually interacting with. Now there are probably a whole lot of potential consequences of this research if it holds up to experimental scrutiny. But right now, the one thing I could probably guarantee, is that there will be a subset of those potential consequences that will not be possible once we have a better understanding of what is ACTUALLY happening.
On the flip side, should the researchers be allowed to propose mission profiles that could potentially not pan out due to a fundamental lack of understanding of what is actually going on? Maybe. Though from my perspective I think I am willing to give the primary investigators some leeway in painting a picture of what could be possible. As long as they assume the responsibility of dealing with the fall out if their vision is never realized.
Last topic for the night for me. Someone on this list asked if one could extract energy from the QV. If the QV is GRT space-time, and space-time is the cosmological gravitational field that is created by all the causally connected mass/energy in our section of the universe, then we live in a high pressure sea of gravitational energy. Now if the QV energy state is degradable and locally changeable, then one can posit the possibility of a thermodynamic energy conversion cycle that can extract energy from a pressure difference created in this QV media relative to the QV background average pressure, with a net decrease in this universal gravitational pressure or temperature reflective of the amount of energy so extracted. And try to remember that gravitational energy is negative energy. I'll leave the rest to you folks to draw your own conclusions from what this might mean...
Best, Paul March
Entropically speaking, are there any other shapes for which we can write an analytic dispersion relation ?
And where did I leave my Gunn diode oscillator ?
I think that frobnicat is simply saying that
IF there is a system (any system) that generate a given thrust when it's fed a given electrical power (with no other parameters affecting the thrust) THEN it can be used to generate power, at least theoretically.
This implication doesn't necessitate knowledge of quantum physics, it's simply basic physics.
The interesting question is then "Is EMdrive a system that generate a given thrust when it's fed a given electrical power?"
If it is, we can generate power with EMdrive. It is an useful information: it means that, since free energy doesn't exist, we take this energy from somewhere.
If it isn't, knowing which parameters affect the thrust will probably give us some insight into how EMdrive generate thrust.
(as usual, if we assume that the thrust is not an artefact)
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?
(http://tommytoy.typepad.com/.a/6a0133f3a4072c970b01a511f54ee6970c-800wi)
....Because the type of electromagnetic waves that satisfy the boundary conditions at the lateral curved surfaces of a cone are spherical waves. The great Russian/American scientist/engineer Schelkunoff showed this in the 1930's (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1332981#msg1332981). The natural Boundary Conditions for the bases of the cone are thus spherical surfaces.
I also would like to understand to why the curved bottoms of Shawyer's new test rig "makes more sense" , from microwave resonance point of view?
....
..Because of Maxwell's equations, and the paraboloid boundary conditions, the paraboloid cavity actually has the central axis as a forbidden zone for electromagnetic waves, see these mode shapes:
What would be the implications of fe, using a paraboloid (or a hyperboloid) ?
http://mathworld.wolfram.com/Paraboloid.html
A paraboloid has a natural focal point, which probably would create an ever higher H-field intensity, as far as the resonance patterns go?
(http://www.pbs.org/wgbh/nova/teachers/activities/images/3406_solar_focal1.gif)
...
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?
...
I think it's from Shawyer and improperly attributed to Juan Yang on some other web sites: http://emdrive.com/flightprogramme.html (http://emdrive.com/flightprogramme.html)
Someone should ask Roger Shawyer directly about the Chinese version (especially the dimensions of the cavity). He knows a lot about it, since he went there to speak with Juan Yang and give her some advice.
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?
...
I think it's from Shawyer and improperly attributed to Juan Yang on some other web sites: http://emdrive.com/flightprogramme.html (http://emdrive.com/flightprogramme.html)
Someone should ask Roger Shawyer directly about the Chinese version (especially the dimensions of the cavity). He knows a lot about it, since he went there to speak with Juan Yang and give her some advice.
Yes, that Shawyer's Flight Thruster development programme. A 3.85GHz thruster weighing 2.92 Kg,.
(http://emdrive.com/images/thruster1.jpg)
http://emdrive.com/flightprogramme.html
I don't recall estimated dimensions for it. If anybody estimated the dimensions, @aero is the most likely one to have done it.
The photo is a bit blurry and that makes estimating a bit challenging, and there are lens distortions to the photo, but nothing too major. If the concrete block happened to be a common standard size, which of course is no given, then the dimensions would roughly be:
The Finite Element and the Finite Difference calculations of NASA's EM Drive confirm that the electromagnetic fields are spherical standing waves away from the flat ends.
For a given spherical radius, the bigger the cone's angle, the more different is the spherical surface from a flat end, and the more important is to have spherical ends. Kudos to Shawyer for being the first EM Drive researcher to realize this.
....What Chinese drawing are you referring to? Could you please give a link or a reference to it? Thanks
My gut feeling (i know, hardly a scientific approach) says that the chinese drawing has little to no correlation to the real testunit they've build.
The Finite Element and the Finite Difference calculations of NASA's EM Drive confirm that the electromagnetic fields are spherical standing waves away from the flat ends.
For a given spherical radius, the bigger the cone's angle, the more different is the spherical surface from a flat end, and the more important is to have spherical ends. Kudos to Shawyer for being the first EM Drive researcher to realize this.
Got it! It is all about having equal distances for the bouncing waves between the 2 top/bottom surfaces. Basically, it is a truncated spherical cone...
http://mathworld.wolfram.com/SphericalCone.html
thnx for the clarification...
http://eec.wustl.edu/aboutthedepartment/Pages/news-story.aspx?news=7577&source=admin
http://adsabs.harvard.edu/abs/2014NatPh..10..394P
http://ieeexplore.ieee.org/iel7/4563994/4814557/06690216.pdf
Man we need way stronger magnetic fields and better materials in that thing. The more I keep reading about this subject of PT symmetry breaking the clearer it becomes that this is routine.
http://eec.wustl.edu/aboutthedepartment/Pages/news-story.aspx?news=7577&source=admin
http://adsabs.harvard.edu/abs/2014NatPh..10..394P
http://ieeexplore.ieee.org/iel7/4563994/4814557/06690216.pdf
Man we need way stronger magnetic fields and better materials in that thing. The more I keep reading about this subject of PT symmetry breaking the clearer it becomes that this is routine.
To my mind, the most interesting aspect of these papers is the incorporation of non-linear materials generating additional frequency components.
....What Chinese drawing are you referring to? Could you please give a link or a reference to it? Thanks
My gut feeling (i know, hardly a scientific approach) says that the chinese drawing has little to no correlation to the real testunit they've build.
http://eec.wustl.edu/aboutthedepartment/Pages/news-story.aspx?news=7577&source=admin
http://adsabs.harvard.edu/abs/2014NatPh..10..394P
http://ieeexplore.ieee.org/iel7/4563994/4814557/06690216.pdf
Man we need way stronger magnetic fields and better materials in that thing. The more I keep reading about this subject of PT symmetry breaking the clearer it becomes that this is routine.
To my mind, the most interesting aspect of these papers is the incorporation of non-linear materials generating additional frequency components.
Agreed. From the point of view of solving the dispersion problem, the nonlinearity of the materials involved is what makes a difference, at least at first sight ?.
Yes, because drawings that do not look like each other in that compilation refer to different EM Drive designs, as explained in the Chinese text of the different published articles by Juan Yang's team. The fact that Juan Yang has improved on her design and has tested different EM Drive designs does not necessarily mean that there is "little to no correlation to the real test unit they've build". She documents a large number of tests (much more numerous than the tests conducted at NASA Eagleworks, for example).....What Chinese drawing are you referring to? Could you please give a link or a reference to it? Thanks
My gut feeling (i know, hardly a scientific approach) says that the chinese drawing has little to no correlation to the real testunit they've build.
"the Chinese (drawings) do not look alike each others"
http://eec.wustl.edu/aboutthedepartment/Pages/news-story.aspx?news=7577&source=admin
http://adsabs.harvard.edu/abs/2014NatPh..10..394P
http://ieeexplore.ieee.org/iel7/4563994/4814557/06690216.pdf
Man we need way stronger magnetic fields and better materials in that thing. The more I keep reading about this subject of PT symmetry breaking the clearer it becomes that this is routine.
To my mind, the most interesting aspect of these papers is the incorporation of non-linear materials generating additional frequency components.
Agreed. From the point of view of solving the dispersion problem, the nonlinearity of the materials involved is what makes a difference, at least at first sight ?.
As a starting ferinstance, how much native copper oxide is present on the inner surfaces of the cavity ? Enough to convert 10-7 ?
http://eec.wustl.edu/aboutthedepartment/Pages/news-story.aspx?news=7577&source=admin
http://adsabs.harvard.edu/abs/2014NatPh..10..394P
http://ieeexplore.ieee.org/iel7/4563994/4814557/06690216.pdf
Man we need way stronger magnetic fields and better materials in that thing. The more I keep reading about this subject of PT symmetry breaking the clearer it becomes that this is routine.
To my mind, the most interesting aspect of these papers is the incorporation of non-linear materials generating additional frequency components.
Agreed. From the point of view of solving the dispersion problem, the nonlinearity of the materials involved is what makes a difference, at least at first sight ?.
As a starting ferinstance, how much native copper oxide is present on the inner surfaces of the cavity ? Enough to convert 10-7 ?
Excellent question.
....Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?
While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.
The photo is a bit blurry and that makes estimating a bit challenging, and there are lens distortions to the photo, but nothing too major. If the concrete block happened to be the standard width of 440 mm, cited by wikipedia, then the dimensions would be roughly as estimated in the chart.Thanks to @lasoi, from these dimensions for Shawyer's Flight Thruster (a 3.85GHz thruster weighing 2.92 Kg), we can calculate the most important parameter: the cone's half angle thetaw (as per image below), which is, trivially, a function of the flat base diameters and the axial length:
I'm an artist, not a physicist. If these dimensions seem wrong and you have a different guess for the width of the concrete block, let me know and I'll recalculate based on your width standard.
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.If so, nonlinearity of the HD PE used for the dielectric in the NASA Eagleworks tests, rather than occurring by intelligent design, by intentional doping, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.So nonlinearity of the HD PE, rather than being by intelligent design, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.So nonlinearity of the HD PE, rather than being by intelligent design, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
That's a possibility. Could also explain the difference between some chambers w/ and w/o dielectric ???
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.So nonlinearity of the HD PE, rather than being by intelligent design, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
That's a possibility. Could also explain the difference between some chambers w/ and w/o dielectric ???
Still, what types and how much impurity would be necessary to take place in order to have significant nonlinear effects?
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.So nonlinearity of the HD PE, rather than being by intelligent design, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
That's a possibility. Could also explain the difference between some chambers w/ and w/o dielectric ???
Still, what types and how much impurity would be necessary to take place in order to have significant nonlinear effects?
Good question. One of the papers Mulletron brought up:
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6690216
has interesting curves showing the frequency shifts. Maybe Mulletron has a PT input on this point ?
That would certainly throw all kinds of motion induced errors into the mix. Best to carefully rebuild the original configuration.
Anyway, there is an interesting, if probably coincidence, between the reported results in the above paper using a 19 period optical cavity. When you compare their (PT transition) frequency shift to a 2 period cavity you get 2.1 GHz which is of the order of magnitude of the shift (~ 1.7 GHz) the calculation for the Brady cavity.
Probably means nothing....but curious.
There are a lot of references to nonlinear effects in polyethylene, but most seem to be due to impurities of one sort or another.So nonlinearity of the HD PE, rather than being by intelligent design, would be by accidental impurity, due to lax quality control in the manufacture of the industrially supplied bulk HD PE used by NASA Eagleworks.
That's a possibility. Could also explain the difference between some chambers w/ and w/o dielectric ???
Still, what types and how much impurity would be necessary to take place in order to have significant nonlinear effects?
Good question. One of the papers Mulletron brought up:
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6690216
has interesting curves showing the frequency shifts. Maybe Mulletron has a PT input on this point ?
Dr. Rodal & Notsosureofit:
We had an interesting failure in the Eagleworks lab yesterday. That being I was getting ready to pull a vacuum on our copper frustum mounted in its "reverse" or to the right thrust vector position and ran a preliminary data un to see if it was performing in air as it had two weeks ago just before our last RF amplifier died. Sadly it wasn't for it was producing less than half of what it did before and in the wrong direction!
I had Dr. White come in and take a look over my latest test article installation last night and he found that the center 1/4"-20 nylon PE disc mounting bolt that holds the second PE disc to the small OD frustum's PCB endplate was no-longer tensioned as it had been before. In fact it had partially melted at the interface between the two PE discs thus relieving the strain induced by its bolts threads and nut. (There are three ~1.00" 1/4-20 nylon bolts mounted on a ~2.00" radius spaced every 120 degrees that hold the first PE disc to the PCB end cap. There is then a layer of 3/4" wide office scotch tape at the interface between the first and second PE discs and the center 1/4"-20 nylon bolt that hold second PE disc to the first PE disc.)
Apparently not having the PE discs firmly mounted to the frustum's small OD end cap hindered the thrust producing mechanism that conveys the generated forces in the PE to the copper frustum. And/or the melted nylon was hogging all the RF energy in the PE discs due to its higher dissipation factor in its semiliquid state. Either way it looks like there is a high E-field volume where this center nylon bolt hangs out while running in the TM212 resonant mode. Too bad Teflon bolts are so weak even in comparison to the nylon, for its dissipation factor is at least two orders of magnitude lower than the nylon's.
Best, Paul M.
http://www.mcmaster.com/#standard-plastic-rods/=w0bzy0....Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?
While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.
That could be a Rosetta Stone...
Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects....I'd suggest changing significant to any. I doubt this will come because PT symmetry breaking doesn't come out of the box, it is a spontaneous symmetry break brought on by the specific conditions the material is subject to. I honestly think an expert is going to have to examine the spontaneous PT symmetry breaking in Emdrive in order to conclusively rule it in or out. I think the best way to figure it out is to substitute the PE with a perfectly ordered chiral material and see where the thrust goes. As we've discussed,
Apparently not having the PE discs firmly mounted to the frustum's small OD end cap hindered the thrust producing mechanism that conveys the generated forces in the PE to the copper frustum. ...........That dielectric is definitely doing something important. Would be interesting what would happen if a piece of gold leaf was sandwiched behind the PE, just to see what happens to the thrust. This is a hint to an earlier post I made about the perceived importance of the air/dielectric/copper interface, which might me true after all, if there is a giant Casimir force inside the cavity.
Best, Paul M.
http://www.mcmaster.com/#standard-plastic-rods/=w0bzy0....Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?
While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.
That could be a Rosetta Stone...
Website won't let me direct link to it. Can't find that 6.25" dimension. See Rigid HDPE Polyethylene.
...
....What Chinese drawing are you referring to? Could you please give a link or a reference to it? Thanks
My gut feeling (i know, hardly a scientific approach) says that the chinese drawing has little to no correlation to the real testunit they've build.
I think Flyby refers to the fact that the various EmDrive drawings from the Chinese do not look alike each others. See for example the compilation attached. The two last drawings, largely different, even come from the same 2015 paper. All we can say looking at those pictures is the length of their cavity is perhaps shorter than Shawyer's or Eagleworks designs. But the angles and proportions are all different.
1) I was just asking for a link to understand what you were referring to.....What Chinese drawing are you referring to? Could you please give a link or a reference to it? Thanks
My gut feeling (i know, hardly a scientific approach) says that the chinese drawing has little to no correlation to the real testunit they've build.
I think Flyby refers to the fact that the various EmDrive drawings from the Chinese do not look alike each others. See for example the compilation attached. The two last drawings, largely different, even come from the same 2015 paper. All we can say looking at those pictures is the length of their cavity is perhaps shorter than Shawyer's or Eagleworks designs. But the angles and proportions are all different.
Good to see all Chinese drawings at once, I was not familiar with all of them... thnx for that, flux_
The only one that strikes me to be a real world technical drawing would be the bottom right one.
All the rest will most likely be pure schematic/concept drawings, intended rather to explain something and not intended to represent actual build systems.
I'm not doubting they made several designs and tests, but I seriously doubt that every drawing made relates back to a real test or model. Most of these drawings simply do not hold enough technical info to be credible "as build" plans. You can not use those drawings and proportions to base a real build model on them.
Technical drawings do follow a certain code and stick to general conventions.
The majority of those drawings do not follow those... Hence why I say that they "do not correlate" with any real made object. They're not construction drawings, but function as communication drawings, explaining the workings, concepts and layouts. You should not base dimensional extrapolations for a real world object on them.
But hey, I'm merely sharing 30 years of experience handling technical drawings... if you feel I'm wrong on that assumption... I can live with that...the earth will continue spinning.. ;)
That would certainly throw all kinds of motion induced errors into the mix. Best to carefully rebuild the original configuration.
Anyway, there is an interesting, if probably coincidence, between the reported results in the above paper using a 19 period optical cavity. When you compare their (PT transition) frequency shift to a 2 period cavity you get 2.1 GHz which is of the order of magnitude of the shift (~ 1.7 GHz) the calculation for the Brady cavity.
Probably means nothing....but curious.
Using a unidirectional reflectionless PT grating with a nonlinear silicon distributed Bragg reflector (DBR) cavity consisting of: 20 modulation periods of 2 Pi /q = 0.27 micro meters
EDIT;
<<the emergence of the Optical Rogue Waves (ORWs) ( http://en.wikipedia.org/wiki/Optical_rogue_waves ) has been explored based on the system parameters>>
http://arxiv.org/ftp/arxiv/papers/1312/1312.3400.pdf
(http://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Arrayed-Waveguide-Grating.svg/680px-Arrayed-Waveguide-Grating.svg.png)
Sigh...rereading my post, my answer does sound unnecessarily aggressive.... My apologies for that.
1) I was just asking for a link to understand what you were referring to.
2) I was not intending to use any of those drawings to build anything but instead to conduct calculations that take a fraction of a second to calculate. Calculating the frequencies and mode shapes from an estimated geometry and comparing it with the published results quickly tells me how representative was the drawing of the actual build system. That's how for example, we quickly eliminated the @Fornaro estimate of geometry and zeroed in on the @aero and @Mulletron estimates, for example.
Thanks
There is no such thing as a ‘quantum vacuum virtual plasma,’ so that should be a tip-off right there. There is a quantum vacuum, but it is nothing like a plasma. In particular, it does not have a rest frame, so there is nothing to push against, so you can’t use it for propulsion. The whole thing is just nonsense. They claim to measure an incredibly tiny effect that could very easily be just noise.” There is no theory to support the result, and there is no verified result to begin with.source: http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.VOk1XC6pjSg
observers shouldn’t take too seriously the grandiose claims of theorists about what is and is not possible; they should do their experiments and see what the data imply. It would be a shame to miss out on a fantastic discovery because you believed some theorist who told you it couldn’t possibly be there.
I think the following concerns by @seanmcarroll have been addressed in this thread:Quote...and there is no verified result to begin with.source: http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.VOk1XC6pjSg
...The device has also been successfully tested in vacuum.
@ Star-Drive
We've battled the Nylon vs Teflon fasteners for years in our plasma chambers. These days we replace the Nylon ones every run. Teflon holds up very well, just won't take much mechanical load.
... then many scientists tried to replicate their experiment but hopes fell with the large number of negative replications, and the withdrawal of many positive replications.
We've fried a number of nylon bolts and have found that the best way to keep them from getting cooked is to keep them out of the high E-field regions in the cavity. For Instance we tested the copper frustum in its TM010 mode and mounted a 5.0 inch OD by 1.0" thick PTFE disk at the center of the large OD end cap of the copper frustum with one 1/4-20 nylon bolt. We got some large thrust signatures in that configuration, see attached slide, but the dam nylon bolt kept melting and dropping the PTFE discs into the main body of the cavity.
We've fried a number of nylon bolts and have found that the best way to keep them from getting cooked is to keep them out of the high E-field regions in the cavity. For Instance we tested the copper frustum in its TM010 mode and mounted a 5.0 inch OD by 1.0" thick PTFE disk at the center of the large OD end cap of the copper frustum with one 1/4-20 nylon bolt. We got some large thrust signatures in that configuration, see attached slide, but the dam nylon bolt kept melting and dropping the PTFE discs into the main body of the cavity.
Are there low E-field regions across multiple resonance modes that can be used as mounting points to secure the PTFE discs?
Perhaps a more general solution to the problem of melting nylon bolts would be to search diligently for a material that does not melt.
While perhaps more difficult to obtain (read that as "custom manufacture") bolts can be made from almost any solid. I can just imagine Paul with his pen-knife carving a bolt from a wooden dowel rod. Or baking a ceramic bolt in this wife's kitchen oven.
Seriously though, the bolts problem is a materials issue. What are the necessary characteristics of the bolts, then what are the various materials that satisfy those specifications?
Now that we know the specifications, who wants to volunteer to make 4 bolts?
Edit Add: Or maybe there exists an epoxy (glue) that would serve to attach the dielectric disks?
the nylon bolts themselves could be contributing to the measured force we are seeing? It has a much smaller volume than the PE and PTFE discs, but they have a much higher dissipation factor than PE or PTFE that could translate into more work done converting E&M momentum into mechanical forces.
All:
I tried epoxy and superglue bonding the PE and PTFE discs to the frustum end-caps, but these two plastics just happen to be the slickest and hardest plastics to bond to anything else. Drat! And yes I tried to find aluminum oxide or other low-loss dielectric ceramics bolts & nuts in long enough lengths (~2.50") to work in my application with no luck, but I'll admit I didn't look very hard at the time for I had many other things to do.
Aero: I'm not going to start carving out bolts from wood dowels! :) But that does make me wonder if any wood would have a low enough dissipation factor at 2.0 GHz to be useable... So many things to think about...
Best, Paul M.
Surface roughening of the copper and of the HD PE results in mechanical interlocking sites and causes bond
strength to increase dramatically. A surface roughness of approximately 60-125 microinches is often used as a guideline for assemblies that are to be bonded with adhesives. Shotblasting of the copper surface is usually needed. This is an insurmountable problem for your extremely thin copper surface: there is practically no thickness of copper on the fiber-reinforced flat end to be able to roughen the copper.
Paul, I have experience with bonding hard to bond polymers, it can be done successfully, but it is not trivial, as you have also experienced. This combined with the permanent nature of an adhesive, would also lead me to seek bolt alternatives, particularly for an R&D effort were you are going to have to dismantle, disassemble and reconfigure your setup from time to time.
All:
I tried epoxy and superglue bonding the PE and PTFE discs to the frustum end-caps, but these two plastics just happen to be the slickest and hardest plastics to bond to anything else. Drat! And yes I tried to find aluminum oxide or other low-loss dielectric ceramics bolts & nuts in long enough lengths (~2.50") to work in my application with no luck, but I'll admit I didn't look very hard at the time for I had many other things to do.
Aero: I'm not going to start carving out bolts from wood dowels! :) But that does make me wonder if any wood would have a low enough dissipation factor at 2.0 GHz to be useable... So many things to think about...
Best, Paul M.
Do the screws to fix the dielectric inside the frustum go through the end PCB plate ?
In this case, even if the hole in the copper is much smaller than the wavelength (in nylon ?), wouldn't that allow a significant amount of em energy to escape and bounce around between the frustum and vacuum chamber walls ? Aero's simulation with Meep seemed to say that evanescent waves could funnel through much thinner cracks, if not to let escape real travelling photons at least for near field interactions with things outside the frustum...
... then many scientists tried to replicate their experiment but hopes fell with the large number of negative replications, and the withdrawal of many positive replications.
Sad but true. There is, however, somewhat of a renaissance occurring right now with LENR+ (commercially viable LENR). The current most promising method uses a mixture of nickel powder, iron powder, and LiAlH4 heated to 1100 C under pressure. Multiple universities in the U.S. have recently opened programs with full funding to investigate LENR+. Don't count this phenomena out entirely. Coupled with an EM Drive, the space flight applications become very interesting. Admittedly, controversy abounds, and it is still early to say what the probability of success and implications might be, but nonetheless, it doesn't hurt to keep a finger on the pulse on the most current efforts underway.
If you would like I can sputter coat the mating surface to the end plate w/ copper (or something that would make it easier to adhesive bond). Only cost you the postage.....
All:
I tried epoxy and superglue bonding the PE and PTFE discs to the frustum end-caps, but these two plastics just happen to be the slickest and hardest plastics to bond to anything else. Drat! And yes I tried to find aluminum oxide or other low-loss dielectric ceramics bolts & nuts in long enough lengths (~2.50") to work in my application with no luck, but I'll admit I didn't look very hard at the time for I had many other things to do.
Aero: I'm not going to start carving out bolts from wood dowels! :) But that does make me wonder if any wood would have a low enough dissipation factor at 2.0 GHz to be useable... So many things to think about...
Best, Paul M.
The marine adhesive made by 3M (5200 or 5220 fast cure) will stick to anything; even under water. I have used it on HDP. Most adhesives will just drop off once they have cured. One trick I learned for gauging the dissipation factor of a plastic is to put it in a microwave oven at high power for 10 minutes; or less. But I think the problem you are seeing is not from the dissipation factor of the plastic because your power level is relatively low. Try putting one of the nylon bolts in a microwave and see if it melts. What may be happening is the thin Copper coating is getting very hot and melting the nylon bolt. The radiation pattern from the loop antenna inside the cavity directs most of the rf power to the large end, irrespective of the mode.
A recent publication [Phys. Rev. Lett. 92, 020404 (2004)PRLTAO0031-900710. 1103/PhysRevLett.92.020404] raises the possibility of momentum transfer from zero-point quantum fluctuations to matter, controlled by applied electric and magnetic fields. We present a Lorentz-invariant description using field-theoretical regularization techniques. We find no momentum transfer for homogeneous media, but predict a very small transfer for a Casimir-type geometry.
About half the time when I think this through, the darn thing thrusts backwards.
.....it was producing less than half of what it did before and in the wrong direction!......Apparently not having the PE discs firmly mounted to the frustum's small OD end cap hindered the thrust producing mechanism that conveys the generated forces in the PE to the copper frustum.
@ Star-Drive
We've battled the Nylon vs Teflon fasteners for years in our plasma chambers. These days we replace the Nylon ones every run. Teflon holds up very well, just won't take much mechanical load.
Notsosureofit:
We've fried a number of nylon bolts and have found that the best way to keep them from getting cooked is to keep them out of the high E-field regions in the cavity. For Instance we tested the copper frustum in its TM010 mode and mounted a 5.0 inch OD by 1.0" thick PTFE disk at the center of the large OD end cap of the copper frustum with one 1/4-20 nylon bolt. We got some large thrust signatures in that configuration, see attached slide, but the dam nylon bolt kept melting and dropping the PTFE discs into the main body of the cavity. Brother did that look like a magnitude 9 earthquake on our uN resolution force measurement system!
That said, I'm wondering if the nylon bolts themselves could be contributing to the measured force we are seeing? It has a much smaller volume than the PE and PTFE discs, but they have a much higher dissipation factor than PE or PTFE that could translate into more work done converting E&M momentum into mechanical forces.
Best, Paul M.
http://www.tara.tcd.ie/handle/2262/38886
http://www.ncbi.nlm.nih.gov/pubmed/16711970
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.96.130402QuoteA recent publication [Phys. Rev. Lett. 92, 020404 (2004)PRLTAO0031-900710. 1103/PhysRevLett.92.020404] raises the possibility of momentum transfer from zero-point quantum fluctuations to matter, controlled by applied electric and magnetic fields. We present a Lorentz-invariant description using field-theoretical regularization techniques. We find no momentum transfer for homogeneous media, but predict a very small transfer for a Casimir-type geometry.
An oldie but goodie. These are the older papers. Note the bold part.
I bet that having those PE discs smashed up against each other and the copper is important! From what Paul reported, it is. Here's why I think so:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1329454#msg1329454
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1329531#msg1329531
Quoting me.QuoteAbout half the time when I think this through, the darn thing thrusts backwards.
Quoting @Paul March http://forum.nasaspaceflight.com/index.php?topic=36313.msg1335190#msg1335190Quote.....it was producing less than half of what it did before and in the wrong direction!......Apparently not having the PE discs firmly mounted to the frustum's small OD end cap hindered the thrust producing mechanism that conveys the generated forces in the PE to the copper frustum.
Paul, would you be willing to introduce a small gap between the copper and PE as a test? Like tighten down the Nylon bolts and wedge a wooden shim in there?
Also, I know this is kinda high speed, but do you have any gold leaf? To wedge between the PE and Copper? http://en.wikipedia.org/wiki/Gold_leaf#Culinary_uses
The reason I'm saying all this is, if we're gonna call these things Quantum Vacuum thrusters, we need to treat it like a Casimir experiment, instead of a plasma thruster.
Break:
IRT the new stuff I've been posting about PT symmetry, this is a nice plain english rundown of how it works from different people, saying the same thing as the other researchers.
http://www.lap.physik.uni-erlangen.de/lap/?page=research_krstic_chiral&language=en (Also see those references at the bottom, this is very exciting stuff. I think I may actually be right on this one ;) )
And onto the subject of the Nylon bolts:
So there's a bunch of different types of nylon. Anyone know what kind of nylon those bolts might be made of? Wouldn't it be something if nylon was doing some of the thrusting the whole time.
I feel really goofy right now holding a mirror up to the computer screen.
....
Treat this thing as a large collection of Casimir Cavities, might work if I can convince Dr. White to do so, and only after we both read through your referenced papers on the topic. And oh yes, get to Glenn Research Center for a successful replication of what we've seen to date before the end of March, or I may find myself in retirement before I was ready...
..
....
Treat this thing as a large collection of Casimir Cavities, might work if I can convince Dr. White to do so, and only after we both read through your referenced papers on the topic. And oh yes, get to Glenn Research Center for a successful replication of what we've seen to date before the end of March, or I may find myself in retirement before I was ready...
..
I put the emphasis on:
get to Glenn Research Center for a successful replication of what we've seen to date before the end of March, or I may find myself in retirement
That would be a horrible waste of human talent and experience, somebody extremely difficult to replace, particularly after demonstrating that the EM Drive works in a hard vacuum, and given the better funded efforts in China, that the US should match or exceed.
Those who think that the EM Drive technology is being pursued "under wraps" in the US appear to be misinformed and disconnected from Aerospace Companies Mgt and federally-funded R&D.
There is a shortfall of funds at NASA, and federally-funded R&D in general under present budget conditions.
There is barely more than one month left until the end of March.
People interested in the EM Drive: this shortfall of funds is real, and EM Drive R&D in the US is in clear and present danger.
(http://images.bwbx.io/cms/2014-11-26/pol_researchchart49_315.jpg)
(https://leadingspace.files.wordpress.com/2010/10/budget3.png)
By the looks of things, there will be another "sputnik" moment--but this time it will be the Chinese not the Russians, and the EM Drive not the satellite. As much as I'd like to see the US stay out ahead on this one, if the new sputnik-EM Drive-China moment needs to happen to revive the support of the US government and spur a corresponding rise in NASA's budget, then let's hope it happens, and soon.
Dr. Rodal:
Thanks for the concern over my employment, but everyone is replaceable to one degree or another. And there are at least two federal civil servants involved with the Eagleworks Lab that will carry on, albeit a bit more slowly, if I have to find other activities to fill my golden years. Activities like finishing my home lab that has been on hold since going back to work at the NASA/JSC/Eagleworks Lab for the last four years helping mature Dr. White's QVF vision. What will be, will be. Now back to trying to understand how these EM-Drives might actually work...
Best, Paul M.
It's almost as though the NASA establishment is reluctant to put too many resources into it for fear of looking bad if it doesn't pan out. You hope that isn't the case. If it doesn't pan out it doesn't pan out. But you don't have to be a rocket scientist to see the potential if it does happen to work. I've read that NASA doesn't or can't accept crowdfunding, which is a shame if true- and a bit odd since its entire budget is basically crowd funding through tax revenues.
By the looks of things, there will be another "sputnik" moment--but this time it will be the Chinese not the Russians, and the EM Drive not the satellite. As much as I'd like to see the US stay out ahead on this one, if the new sputnik-EM Drive-China moment needs to happen to revive the support of the US government and spur a corresponding rise in NASA's budget, then let's hope it happens, and soon.
Well if the reports from China are true, if we don't roll out something impressive soon, they already beat us to the punch. :(
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSy7QjdoZl-0e9HJLqKx4pkexxWDGg_7Km6Qr1eZ_kR_p28tiY0RCN0Fcrcfg)
http://www.economist.com/node/11791539
Dear excellent NSF forum. This is just to say (for those who don't know) that I've suggested a specific new model for inertia that predicts galaxy rotation without dark matter (it is called MiHsC) and I recently compared its predictions with the 9 EmDrive results with 'some' (not perfect) success. You can see the results by looking at the Table here:Yes, as (arguably) the greatest Mathematician/Physicist in recent times (John Von Neumann) wrote:
http://physicsfromtheedge.blogspot.co.uk/2015/02/mihsc-vs-emdrive-data-3d.html
I've also published a paper summarising this comparison (slightly out of date now) here
http://www.ptep-online.com/index_files/2015/PP-40-15.PDF
I'd encourage those with other interesting explanations of the EmDrive to make a similar comparison between predictions and data, so we can compare using the facts. If you have any more data points to add, or if you disagree with the numbers in my Table, please let me know.
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
@ RODAL
Arrgh, Mondays !
Looked over my bleary weekend, noticed I was using diameters AGAIN !
Mode Frequency (MHz) Quality Factor, Q Input Power (W) Mean Thrust (μN) Calculated w/o
dielectric
TE012 1880.4 22000 2.6 55.4 10.8
TM212 1932.6 7320 16.9 91.2 38.5
TM212 1936.7 18100 16.7 50.1 93.5
TM212 1937.115 6726 50 66 104.0
Anyway, shows it pays to rewrite everything in the same place !
....
Great !
In order to understand the above, (please correct me if I am wrong), you used in your formula the actual frequency and mode shapes that took place in the EM Drive experiment with the dielectric so in that sense you did calculate with the dielectric in a very restricted sense.
FYI
Cleanup and de-typo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity, no dielectric)
Starting with the expressions for the frequency of a cylindrical RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[sub m,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into Doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
Slow goin', thanks for your patience.
Excellent! Thank you for posting the complete equations.
One suggestion: In the expression NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
the speed of light in vacuum "c" appears in the numerator without being divided by the SquareRoot of the relative electric permittivity and relative magnetic permeability.
Since the relative electric permittivity of the dielectric is 2.3, this would decrease the values in the table by a factor of Sqrt[2.3]=1.52 if the whole cavity would be occupied by the dielectric. Granted that only a portion of the truncated cone contains the dielectric, which will decrease the dividing factor, but any amount will reduce the effective value of c in the medium, giving lower thrust and hence values closer to the experimental measurements.
For example, very roughly, assuming that 1/3 of the longitudinal length is occupied by the dielectric, and using the average as a medium with those average properties, Sqrt[(2.3*1/3)+1*(2/3)]=1.20, the thrust values would be reduced by a factor of 1.20, so for the most important test (the one in recently performed in vacuum, -the other experimental values may have been affected by thermal convection effects in the air and are therefore less reliable-), instead of 104 μN you would get 87 μN, which better compares with the experimental value of 66 μN.
This stuff is all an interesting thought exercise, but there's no way it's a Sputnik moment when bulk of the physics community are scoffing at it. Just as with the Hafnium controversy (http://en.wikipedia.org/wiki/Hafnium_controversy), it would be nice to see the mainstream physics community roped in to at least do an authoritative disproof on it, rather than leaving things to linger on under imagination and speculation.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608thank you :)
Anyway, still thinking about a possible experiment in vacuum using:Do you have this report by Brito, Marini and Gallian, using a Cavendish balance, batteries for power input, oil damping, counterweight and laser measurements ? http://enu.kz/repository/2009/AIAA-2009-5070.pdf
https://www.dropbox.com/s/cmxyj7re8rrb6dh/IMAG0361.jpg?dl=0
to make a stack chamber like:
https://www.dropbox.com/s/wf8wv226h8138n1/IMAG0360.jpg?dl=0
but on an isolation stand.
The idea would be to then balance a tapered oscillator (Gunn Diode ?) cavity and a battery pack w/ a remote photo-switch on a beam held by a suspension fiber and monitor the rotation. I'm thinking one could get some sensitivity multiplication by switching the cavity on and off in time w/ the oscillation frequency of the assembly (easy to do w/ a digital camera) and see if the oscillation amplitude increases w/ time.
Anyone want to try a sensitivity calculation ? Comments ?
.....
The idea would be to then balance a tapered oscillator (Gunn Diode ?) cavity
Anyway, still thinking about a possible experiment in vacuum using:Do you have this report by Brito, Marini and Gallian, using a Cavendish balance, batteries for power input, oil damping, counterweight and laser measurements ? http://enu.kz/repository/2009/AIAA-2009-5070.pdf
https://www.dropbox.com/s/cmxyj7re8rrb6dh/IMAG0361.jpg?dl=0
to make a stack chamber like:
https://www.dropbox.com/s/wf8wv226h8138n1/IMAG0360.jpg?dl=0
but on an isolation stand.
The idea would be to then balance a tapered oscillator (Gunn Diode ?) cavity and a battery pack w/ a remote photo-switch on a beam held by a suspension fiber and monitor the rotation. I'm thinking one could get some sensitivity multiplication by switching the cavity on and off in time w/ the oscillation frequency of the assembly (easy to do w/ a digital camera) and see if the oscillation amplitude increases w/ time.
Anyone want to try a sensitivity calculation ? Comments ?
I've tried to do searches of multiple types, and have read a few dozen posts, but I still can't answer what seems to be a very simple question, so I'm going to ask.The amplification is the Q resonance. The problem is that there are supposed to be no photons whatsoever coming out of the thruster if the EM drive is completely enclosed as a resonant cavity.
Has anyone verified that this isn't turning itself into some type of amplified photonic thruster?
I've tried to do searches of multiple types, and have read a few dozen posts, but I still can't answer what seems to be a very simple question, so I'm going to ask.
Has anyone verified that this isn't turning itself into some type of amplified photonic thruster?
there can be no amplification of these waves since evanescent waves are exponentially decaying (not resonant) by definition
.....
The idea would be to then balance a tapered oscillator (Gunn Diode ?) cavity
Disassembled radar speed gun. The grey assembly attached to the end of the copper-colored horn antenna is the Gunn diode oscillator which generates the microwaves.
From Wikipedia http://en.wikipedia.org/wiki/Gunn_diode
Do you have this report by Brito, Marini and Gallian, using a Cavendish balance, batteries for power input, oil damping, counterweight and laser measurements ? http://enu.kz/repository/2009/AIAA-2009-5070.pdf
.....
The idea would be to then balance a tapered oscillator (Gunn Diode ?) cavity
Disassembled radar speed gun. The grey assembly attached to the end of the copper-colored horn antenna is the Gunn diode oscillator which generates the microwaves.
From Wikipedia http://en.wikipedia.org/wiki/Gunn_diode
Yup! That should do it. Haven't found where I put that Gunn oscillator yet (just had it a couple months ago)
If anyone has one of those speed guns in the drawer I won't ask where you got it .......
I thought somewhere Dr March had said that GRS's balance sensitivity required an improvement of the thrust signal by 100 percent in order to get successful replication. Did I get that right? I cannot find it now and I have been looking back through the thread for 20 minutes or more. -Anyway; with a deadline of EOM, march; does that mean there is an improved test article about to or in the process of undergoing additional testing at Eagleworks? and can someone link to where that fact (GRS sensitivity limits incapable of detecting current thrust signal level) was posted for reference?
The Glenn Research Center (GRC) torque pendulum test rig has a reported sensitivity of ~50 micro-Newton (uN), so we will need a consistent copper frustum thrust performance of at least 100uN to be assured of a successful replication effort at the GRC facility. And no we don't have another test article that performs better than the copper frustum
would deacclerating superluminal waves release Cherenkov radiation? If so; where is the blue glowy stuff? (i like blue glowy stuff. ) Wouldn't a light intensifying camera detect Cherenkov radiation even if there is not enough to be visible to the naked eye?I've tried to do searches of multiple types, and have read a few dozen posts, but I still can't answer what seems to be a very simple question, so I'm going to ask.
Has anyone verified that this isn't turning itself into some type of amplified photonic thruster?
I have suggested something like that. Photons with superluminal momentum or superluminal velocity (a different reference) escaping the cavity via evanescent waves. The references haven't gotten much traction and I've busy with meep so haven't delved into the math. http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf) (See Appendix B, page 15.) People who've looked at the reference get hung up on the causality paradox and can't seem to get past that to look at the math.
My opinion on that is that if the math gives good estimates of the thruster performance, then maybe the paper's author has a valid argument about the causality paradox. Or maybe delve into the tachyon math to see if the paradox really exists in this case.
@Rodal -
Quotethere can be no amplification of these waves since evanescent waves are exponentially decaying (not resonant) by definition
But I think that is the part of the point where the math of superluminal evanescent waves diverge from the classic math. The reference claims to show that the velocity of the wave is a function of the cavity diameter and the gap diameter. If that function of velocity is anything like diameter divided by gap size then the momentum of a single photon could be amplified enormously. Huge momentum from a small number of photons and small number of photons from a small power consumed.
I guess I'll have to set meep aside and delve into MAXIMA just to satisfy myself.
where is the blue glowy stuff? (i like blue glowy stuff. )
i know if you remove the IR filter from a regular electronic camera you can turn a normal camera (on a cell phone for example) into a night vision camera. Perhaps there is a way to hack a camera to do the same thing with UV light.
QuoteThe Glenn Research Center (GRC) torque pendulum test rig has a reported sensitivity of ~50 micro-Newton (uN), so we will need a consistent copper frustum thrust performance of at least 100uN to be assured of a successful replication effort at the GRC facility. And no we don't have another test article that performs better than the copper frustum
You may have to resort to the Chinese method, and latch in the most powerful magnetron you can lay hands on.
QuoteThe Glenn Research Center (GRC) torque pendulum test rig has a reported sensitivity of ~50 micro-Newton (uN), so we will need a consistent copper frustum thrust performance of at least 100uN to be assured of a successful replication effort at the GRC facility. And no we don't have another test article that performs better than the copper frustum
You may have to resort to the Chinese method, and latch in the most powerful magnetron you can lay hands on.
...NASA Eagleworks has not used a hanging pendulum for their measurements.
I take it that this is a hanging Pendulum? ...
...NASA Eagleworks has not used a hanging pendulum for their measurements.
I take it that this is a hanging Pendulum? ...
They have used a low thrust torsion pendulum. See the report for further details: http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
...NASA Eagleworks has not used a hanging pendulum for their measurements.
I take it that this is a hanging Pendulum? ...
They have used a low thrust torsion pendulum. See the report for further details: http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
Could a magnetic field cause issus with this sort of pendulum? Especially some form of rotating field?
QuoteDo you have this report by Brito, Marini and Gallian, using a Cavendish balance, batteries for power input, oil damping, counterweight and laser measurements ? http://enu.kz/repository/2009/AIAA-2009-5070.pdf
Possibly a stupid question, but was this team using the most productive 'mode/frequency' for the size of their frustum? Having the right mode seems to be crucial to the correct functioning of this device.
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?
...
I think it's from Shawyer and improperly attributed to Juan Yang on some other web sites: http://emdrive.com/flightprogramme.html (http://emdrive.com/flightprogramme.html)
Someone should ask Roger Shawyer directly about the Chinese version (especially the dimensions of the cavity). He knows a lot about it, since he went there to speak with Juan Yang and give her some advice.
Yes, that Shawyer's Flight Thruster development programme. A 3.85GHz thruster weighing 2.92 Kg,.
(http://emdrive.com/images/thruster1.jpg)
http://emdrive.com/flightprogramme.html
I don't recall estimated dimensions for it. If anybody estimated the dimensions, @aero is the most likely one to have done it.
I did not. I see nothing to use as a reference. Perhaps someone could estimate ratios. Big/small, big/height or whatever.
The photo is a bit blurry and that makes estimating a bit challenging, and there are lens distortions to the photo, but nothing too major. If the concrete block happened to be the standard width of 440 mm, cited by wikipedia, then the dimensions would be roughly as estimated in the chart.
I'm an artist, not a physicist. If these dimensions seem wrong and you have a different guess for the width of the concrete block, let me know and I'll recalculate based on your width standard.
Overall diameter | 265 mm |
Overall height | 164 mm |
Weight | 2.92 kg |
Operating frequency | 3.85 GHz |
Unloaded Q | 60,000 |
Input power | 150 to 450 W |
Max. measured thrust | 174×10−3 N |
Average specific thrust | 326×10−3 N/kW |
Secrets of Antigravity Propulsion Figure 8.4 - copy past this into the Google search. Click the first link it opens up the chapter and the figure 8.4 (interesting picture) Mr. Paul March spoke about. Very interesting reading Mr. Paul, thank you.
A major part of the work is in the development of the frequency tracking algorithm. This is needed to ensure the input frequency matches the resonant frequency of the high Q (60,000) cavity, over the full input power range and the qualification temperature specification.
The thruster is designed to be powered from existing flight qualified TWTAs, which are driven from a dual redundant frequency generator unit (FGU) The FGU includes a frequency control loop using feedback signals from the thruster.
According to those figures the frustum height is only 62% of the base diameter. But the height of the frustum in the photo is 75% of its base diameter, and that's excluding the nuts atop the small endplate. If we included those then the percentage would be even greater, closer to 80% of the base diameter. Are we sure those are the correct measures for the frustum in the photo? The distortion in the photo, which is primarily around the periphery, isn't nearly enough to account for that much discrepancy. I don't mind being wrong but I don't see how those numbers jive with the photo.For clarity, could you please let us know what you think are the best estimates?
Edit, I see what he's done. He has excluded the height of the base of the frustum and the height of the top of the frustum from the frustum's overall height. If we exclude these in the photo, then the frustum height is almost exactly 62% of the base diameter. So it works out perfectly. (Sorry for the misunderstanding. I'm an artist, not a scientist, lol.)
And the diameter of the top cap is 189mm, give or take a mm or two.
Big diameter is 265 mm
Small diameter is 189 mm
Height is 164 mm.
Big diameter is 265 mm
Small diameter is 189 mm
Height is 164 mm.
If the diameter of the base and top are measured from where the frustum meets the base and top caps, then Shawyer's numbers (265mm base and 164mm height) don't fit the photo. But if the diameter of the base and top are measured from the widest parts of the end caps, then they fit perfectly with the photo.
If you like I'll make another chart to show you what I mean but it'd take twenty minutes or so.
...NASA Eagleworks has not used a hanging pendulum for their measurements.
I take it that this is a hanging Pendulum? ...
They have used a low thrust torsion pendulum. See the report for further details: http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
...
And you can see this negative longer term frustum thermal drift by noting the downward going baseline slope of the thrust trace even after the RF power is removed from the copper frustum.
...
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776497;image)
Sorry to keep harping on this, I'll soon be done and out of the way. But I just wanna make sure I get this right. Can someone answer the question on the chart?
....That's incorrect.
Later on thread 2 (related to spaceflight) while explaining why the buckling analysed by Rodal ... would make a ... thrust in opposite direction to the one observed by the pendulum, ...
Thanks. I'll assume the interior walls are the same thickness as the frustum walls where they flare out and attach to the plate. We can see their thickness there.Sorry to keep harping on this, I'll soon be done and out of the way. But I just wanna make sure I get this right. Can someone answer the question on the chart?
At least for the internal height, the junction between the plates is the place to measure from.
The internal diameters need to know the wall thickness of the cone etc.
That whole thing looks like he used (standard ?) heavy duty vacuum/pressure components.
An interesting bit of information over on TP, here:
http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5830 (http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5830)
I would post to the link but for some reason my computer is forbidden to access the arxiv web site. Anyone know why that might be?
Anyway, seems that in looking at the Juno fly-by anomaly they have came up with a "new" force relating angular and linear momentum. Seemingly would also work for electrical phenomenon and it might even be of the right order of magnitude to be of interest to us here.
....That's incorrect.
Later on thread 2 (related to spaceflight) while explaining why the buckling analysed by Rodal ... would make a ... thrust in opposite direction to the one observed by the pendulum, ...
The buckling analysis (thermal instability) gives a force precisely in the same direction as measured.
It was the thermal expansion explanation (advanced by Oak Ridge Labs in another context) that gives a force in the completely opposite direction.
Please refer back to the original image to see that the thermal expansion force (of the dielectric, which is what thermally expands the most, as per Oak Ridge) is the one in the wrong direction.
The buckling on the end plate is in the opposite direction to the thermal expansion of the dielectric.
Buckling movement of the large diameter end is towards the left, and the buckling force is towards the left. (Paul indicates it as "oil canning" of the flat plate).
Now Newton's third law still states that for every action there is an equal and opposite reaction. So when the copper frustum's large OD end-cap's prompt and inward oil canning action, followed by the slower frustum cone thermal expansions, they both push the copper frustum's Center of Mass (CoM) to the left as viewed from the front of the Eagleworks' vacuum chamber looking back at the test article and torque pendulum, while noting how the copper frustum is bolted on to the T.P.. These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
Thermal expansion of the HD PE dielectric is towards the right.
Movement of the EM Drive is towards the left, exactly the same direction as the buckling movement, and the same as the buckling force.
The buckling force is analogous to somebody pushing (actually bending) the center of the end plate towards the left, which will deflect the plate inwards. If the structure (the EM Drive) is free to move, it will move to the left, as a consequence of the plate being pushed inwards towards the left.
The buckling force perfectly explains the initial impulse magnitude, time duration of the impulse, and direction of travel. The buckling force cannot explain the sustained 40 sec force, hence the buckling force explanation is rejected on the grounds that it cannot explain the 40 sec duration of the force.
The thermal expansion explanation is rejected, upon inspection, on several grounds that the thermal expansion movement (of the HD PE) is in the opposite direction as the movement of the EM Drive, rejected on the basis that the HD PE has a free surface, hence free to expand, and therefore there should be no force arising from an unrestrained isothermal homogeneous thermal expansion. Thermal stresses arise in restrained materials or those under a temperature gradient or those with anisotropic coefficients of thermal expansion. This follows from the equations of thermoelasticity. The equations presented in the Oak Ridge report do not abide by the equations of thermoelasticity (Boley and Wiener).
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776495;image)
An interesting bit of information over on TP, here:
http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5830 (http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5830)
I would post to the link but for some reason my computer is forbidden to access the arxiv web site. Anyone know why that might be?
Anyway, seems that in looking at the Juno fly-by anomaly they have came up with a "new" force relating angular and linear momentum. Seemingly would also work for electrical phenomenon and it might even be of the right order of magnitude to be of interest to us here.
(Bold added for emphasis)....That's incorrect.
Later on thread 2 (related to spaceflight) while explaining why the buckling analysed by Rodal ... would make a ... thrust in opposite direction to the one observed by the pendulum, ...
Maybe, but it appears Paul March in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) says that it is opposite, and I don't see that this disagreement was acknowledged ...
Dr. Rodal analyzed possible thermal instability (thermal buckling of the flat ends) as a cause for the measured thrust and reported this at NSF and at ResearchGate (https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT). A thermo-mechanical effect (thermal buckling) is shown that occurs in less than 1 second (for the copper thickness employed for the microwave cavity), with a temperature increase of a degree C or less and that results in forces of the same magnitude as reportedly measured by NASA. Moreover, this thermal instability produces forces in the same direction as measured, and it will occur in a vacuum (since the heating can be due either to induction heating from the axial magnetic field in a TE mode or resistive heating due to the axial electric field in a TM mode). However, this effect can only explain the initial impulsive force and cannot explain the longer 30 to 40 second measured force. Thus the thrust force measured for up to 40 second is not nullified by this explanation either.(Bold and color added for emphasis)
Thermal expansion effect as posited by a team from Oak Ridge National Labs for another propellant-less set of experiments was also eliminated as a possible source by the NSF contributors because it would result in forces in the complete opposite direction as the forces measured by NASA.
.....The mathematical equations I used are in the aforementioned paper, if you object to any of the equations and assumptions we would have a better basis for discussion.
I have to think again about all that. ...
I've probably got the thickness of the frustum walls wrong but it's difficult to gauge because where the frustum walls flare out at the bottom and attach to the base cap they appear to be thinner than where they flare out at the top and attach to the top cap. I wish the photo was from a lower point of view so we could see beneath the top rim of the thing.
At any rate I can't get the dimensions of the inner cavity in the photo to jive with Shawyer's numbers. So I'm at a loss. I will say that it's a pretty remarkable coincidence that his numbers work precisely with the measurements in the photo if we use the diameters of the base and top caps, rather than the estimated diameters of the inner cavity, whatever they may be.
I'll post the chart just for the sake of having it visible. Like I said, the two diameter scales must be incorrect. My best guess for "overall" diameter of the top, would be 189mm.
(Bold added for emphasis)....That's incorrect.
Later on thread 2 (related to spaceflight) while explaining why the buckling analysed by Rodal ... would make a ... thrust in opposite direction to the one observed by the pendulum, ...
Maybe, but it appears Paul March in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) says that it is opposite, and I don't see that this disagreement was acknowledged ...
The fact that the thermal instability (buckling force) cannot be used to nullify the EM Drive thrust, was explicitly acknowledged by me and explained here http://forum.nasaspaceflight.com/index.php?topic=36313.msg1336196#msg1336196:QuoteDr. Rodal analyzed possible thermal instability (thermal buckling of the flat ends) as a cause for the measured thrust and reported this at NSF and at ResearchGate (https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT). A thermo-mechanical effect (thermal buckling) is shown that occurs in less than 1 second (for the copper thickness employed for the microwave cavity), with a temperature increase of a degree C or less and that results in forces of the same magnitude as reportedly measured by NASA. Moreover, this thermal instability produces forces in the same direction as measured, and it will occur in a vacuum (since the heating can be due either to induction heating from the axial magnetic field in a TE mode or resistive heating due to the axial electric field in a TM mode). However, this effect can only explain the initial impulsive force and cannot explain the longer 30 to 40 second measured force. Thus the thrust force measured for up to 40 second is not nullified by this explanation either.(Bold and color added for emphasis)
Thermal expansion effect as posited by a team from Oak Ridge National Labs for another propellant-less set of experiments was also eliminated as a possible source by the NSF contributors because it would result in forces in the complete opposite direction as the forces measured by NASA.
...
Now Newton's third law still states that for every action there is an equal and opposite reaction. So when the copper frustum's large OD end-cap's prompt and inward oil canning action, followed by the slower frustum cone thermal expansions, they both push the copper frustum's Center of Mass (CoM) to the left as viewed from the front of the Eagleworks' vacuum chamber looking back at the test article and torque pendulum, while noting how the copper frustum is bolted on to the T.P.. These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
....
So to make my position explicit in regard to observables : I predict that the consequence of an "inward oil canning" is a sharp plunge on the record charts (or to add a sharp plunge term to other possible effects that move the arm). And I also think Paul March sees that the same way. Will take time to further reply of your next post, unless other contributors feel it clutters the main thread and we could discuss that by PM.
Quickly, before I address the rest of your post in more depth... I wouldn't insist on that point if I didn't feel that the opposite is untenable :).....The mathematical equations I used are in the aforementioned paper, if you object to any of the equations and assumptions we would have a better basis for discussion.
I have to think again about all that. ...
To state that the buckling forces produces a force (towards the right in the picture), in the opposite direction to the measured movement and force of the EM Drive (towards the left in the picture) is, I think, untenable.
...
FYI
Anytime I hear the term "Two-Photon Loss"...........
http://arxiv.org/pdf/1412.4633v1.pdf
"In conclusion, we have realized a non-linearly driven-dissipative oscillator which spontaneously evolves towards the quantum manifold spanned by two coherent states."
And
"This was achieved by attaining the regime in which the photon pair exchange rate is of the same order as the single photon decay rate. The ratio between these two rates can be further improved within the present technology by using a higher Q oscillator and increasing its on-linear coupling to the bath."
For whatever it's worth. (requires non-linear elements. surface ? also ignored some terms ?)
@FlybyWell, it might be interesting to pretend we do not know the real dimensions and see if such a photo-touch up can be used to make more accurate measures.. or... that it proves to be totally useless...
The second type distortion you refer to is a perspective distortion. All of that is true and in addition the camera wasn't held on a flat level when the photo was taken. I've rotated it a few degrees clockwise to compensate for this problem but I might still be off of the horizontal by a fraction of a degree. At any rate my experience is that these distortions are so small that they don't significantly affect the accuracy of the estimate, which is a just that, a rough estimate give or take a couple mms.
If you have the software and are able to correct for some of the distortion, I'll recalculate. I'm not sure that it matters much but I'd be happy to do so.
FYI
Anytime I hear the term "Two-Photon Loss"...........
@FlybyWell, it might be interesting to pretend we do not know the real dimensions and see if such a photo-touch up can be used to make more accurate measures.. or... that it proves to be totally useless...
The second type distortion you refer to is a perspective distortion. All of that is true and in addition the camera wasn't held on a flat level when the photo was taken. I've rotated it a few degrees clockwise to compensate for this problem but I might still be off of the horizontal by a fraction of a degree. At any rate my experience is that these distortions are so small that they don't significantly affect the accuracy of the estimate, which is a just that, a rough estimate give or take a couple mms.
If you have the software and are able to correct for some of the distortion, I'll recalculate. I'm not sure that it matters much but I'd be happy to do so.
I do feel a bit uncomfortable about the tilt-correction, but ignoring it would mean you have to resort to a 3 point perspective, which is highly uncomfortable (horizon points far far away) considering you have a near 1-point perspective...
but... let's give it a spin...if it hits a wall, then we'll know... :)
.....The mathematical equations I used are in the aforementioned paper, if you object to any of the equations and assumptions we would have a better basis for discussion.
I have to think again about all that. ...
To state that the buckling forces produces a force (towards the right in the picture), in the opposite direction to the measured movement and force of the EM Drive (towards the left in the picture) is, I think, untenable.
Here are two tenable positions that can be taken:
1) The buckling force cannot produce any motion of the center of mass of an unconstrained EM Drive free-floating in space. If one assumes simply supported boundary conditions at the edges of the big diameter plate, just before instability takes place, the end plate is flat and hence the membrane forces are balanced by the rigid circular rim. These membrane forces are directed radially from the rim towards the center, they are self-balanced. There are no forces perpendicular to the plate. If one assumes that the buckling instability takes place instantaneously , superluminally, in the buckled state, there are no membrane forces if the plate is infinitesimally thin, such that it will take whatever bent position is necessary to accommodate the required membrane thermal expansion. Since there are no membrane forces in the final buckled state, there are no forces at the simply supported edges at all in the buckled state. Hence there are no forces to move the EM Drive before and after the buckled state, and that's all, because the buckling motion is assumed to take place instantaneously (hence there are no forces to be considered to take place in between the initial flat state and the final buckled state).
2) If one assumes that buckling cannot take place instantaneously, but that its maximum speed has to be limited by the velocity of stress waves in the material, that is, by the speed of sound in the material, then the minimum time interval for buckling to take place is governed by the speed of sound. In the paper I derived a speed and acceleration for the buckling motion under some assumptions that are explicitly stated (see equations). Those assumptions can indeed be criticized. The equations can also be criticized, and you are invited to do so. The derived speed is below the speed of sound in the material, so it satisfies this physical condition (that the buckling speed should be lower than the speed of sound in the material). After the onset of buckling, and during this (short time) buckling motion, the membrane force decreases, from a maximum at the onset of buckling to a minimum at the final buckling state. During this (short time) the plate is in a bent condition, with increased bending shape with time. At the edges of the plate, the bending of the plate produces a slope at the simply supported edges. The membrane force at the edges can be decomposed into two directions: A) a component that is in the original flat direction. This component is self-balanced. B) The other force vector component is directed in the same direction (towards the left) as the motion of the EM Drive. This is a very short-time impulsive force, calculated to be of the same magnitude as the initial transient rise force in the experiments.
...Get rid of the pendulum and everything else for the time being, as it further muddles the picture.
That's what I have in mind when I say that inward buckling to the left will appear as a kick to the right for the system :
....
From 3 to 4 : the consequence of an "inward oil canning" alone is a kick to the right initially. Do I have to write down equations ? For me this is more a matter of proper forces orientation conventions than anything else. I hope this is clear enough as to why I said that buckling would kick opposite to the observed thrust. So, what's wrong with this way of seeing orientations ?
...Get rid of the pendulum and everything else for the time being, as it further muddles the picture. Just consider the flat plate and a rigid ring around it and ask yourself in which direction you have to push the plate's center for the plate's center to move towards the left. Of course that one has to have a force moving to the left.
That's what I have in mind when I say that inward buckling to the left will appear as a kick to the right for the system :
....
From 3 to 4 : the consequence of an "inward oil canning" alone is a kick to the right initially. Do I have to write down equations ? For me this is more a matter of proper forces orientation conventions than anything else. I hope this is clear enough as to why I said that buckling would kick opposite to the observed thrust. So, what's wrong with this way of seeing orientations ?
All those words and images above are associated with a discussion of a reaction from the pendulum.
You could use all those words to also talk about a reaction from the pendulum concerning EM Drive's thrust, and get into a similar mambo jambo as Shawyer's discussion of thrust in EM Drives.
First you have to address in which direction is the movement of the buckled shape (it is towards the left), and when it moves towards the left , in which direction it is pulling the supports (towards the left). The buckled material cannot move towards the left without pulling on the supports towards the left: it is all connected.
What you are discussing instead is what is the effect of the buckling force pulling the supports to the left, on the pendulum. That is an entirely different question. You can ask yourself exactly the same question regarding what is the effect of the EM Drive moving towards the left, with a force pulling towards the left, on the pendulum.
After you have accepted that fact, you can talk about the reaction, which involves elastic deformation, and it is also present for the EM Drive thrust.
And, it is unclear why you think that this is so relevant, because the flat plate can theoretically buckle towards the left or towards the right (if there would be no plastic insulation on the outside and if the copper would be very thin) depending on initial imperfections. An even if you think that when the buckled plate moves towards the left it gives a force towards the right (which is a misscommunication based on the fact that you are focusing on the pendulum's reaction rather than the buckling force itself, but for argument sake's) then even per your admission then if the plate buckles towards the right according to you would produce a force towards the left.
It seems to me that if you wanted to argue about this for intellectual reasons, a much safer ground would be to say that the buckling force is self-balanced and that it produces no forces on the center of mass, either to the left or to the right (for the aforementioned reasons in my above post).
EDIT: And having said that, the thermal expansion explanation by Oak Ridge does not make any sense in this case for the HD PE (to think that an unrestrained, homogeneous, isotropic, free to expand material, will produce a force when expanding. Thermal expansion changes the VOLUME of a material. The mass stays the same. If free to expand, then the density of the HD PE will change (larger volume, same mass = lower density). Thermal expansion produces forces only when there is a thermal gradient through the material or the material is anisotropic, or the most general case: when the material is constrained so that it cannot expand !!!!! )
...I like your drawings with the buckled condition idealized as a beam with three hinges: one hinge at the center and a hinge at each end. :)
...With respect to the HD PE dielectric, now I see your thinking. I think you think of it as a dynamic problem, for example, if instead of the HD PE we would have an explosive inside the cavity glued to the left wall, the effect of the explosive would be to force the wall towards the left.
??? When thermal expansion displaces a part of a system relative to the rest of a system, the rest of the system will recoil. Whatever displaces a part of a system relative to the rest of the system, this displacement implies a force F_system_part. The rest of the system will recoil. Recoil is the acceleration due to the opposite force (F_part_system). An unrestrained, homogeneous, isotropic, free to expand but in one direction material, will produce a force when expanding against the wall against which it rests.
Why is it so hard to reach consensus now ?
I have some new observations and theory. I lifted the first picture from the Aug. '14 paper, which shows the linear displacement sensor. This device tracks the position of a reflected laser dot on a CMOS image sensor. This is usually done by calculating the center of luminance of the laser dot; a measurement that has an accuracy of a small fraction of the width of a pixel. The second picture describes a typical LDS that has sub-micron accuracy.
The only control or "NULL" experiment described in the Aug. 14 paper related to the Eagleworks device was when the dummy load was used instead of sending RF into the cavity. This of course shields the RF very well. The dummy load is 50 Ohms and so the SWR is 1:1. However when the cavity is loaded and the dielectric material is inside the cavity it's possible the SWR is much higher. This would result in RF being reflected back to the amplifier and being radiated from the shield of the RF cable. This is what happens when the SWR is not 1:1. It's possible this RF noise is interfering with the LDS. When the dielectric is not inside the cavity the SWR is lower so no interference takes place. This theory agrees with the results of the cannae test as well.
The last picture, also from the Aug. '14 paper shows a negative slope on the baseline position ( no thrust) after each RF pulse. The first one appears to level off just before the final RF pulse. After that pulse it heads down again. I believe the thermally induced change in the CoM of the emdrive causes the balance arm to rotate. This very slight rotation reduces the reflection distance for the laser beam.
While formulating the steps i've used to get to that result, I've concluded I made an error in the last correction step. I took the wrong side for the horizontal (camera yawn distortion) perspective correction.
What software did you use to do that?
I have in the past used Mathematica to transform images like that but one has to write Mathematica code to get it just right like you did.
Dr. Rodal & Notsosureofit:
We had an interesting failure in the Eagleworks lab yesterday. That being I was getting ready to pull a vacuum on our copper frustum mounted in its "reverse" or to the right thrust vector position and ran a preliminary data un to see if it was performing in air as it had two weeks ago just before our last RF amplifier died. Sadly it wasn't for it was producing less than half of what it did before and in the wrong direction!
I had Dr. White come in and take a look over my latest test article installation last night and he found that the center 1/4"-20 nylon PE disc mounting bolt that holds the second PE disc to the small OD frustum's PCB endplate was no-longer tensioned as it had been before. In fact it had partially melted at the interface between the two PE discs thus relieving the strain induced by its bolts threads and nut. (There are three ~1.00" 1/4-20 nylon bolts mounted on a ~2.00" radius spaced every 120 degrees that hold the first PE disc to the PCB end cap. There is then a layer of 3/4" wide office scotch tape at the interface between the first and second PE discs and the center 1/4"-20 nylon bolt that hold second PE disc to the first PE disc.)
Apparently not having the PE discs firmly mounted to the frustum's small OD end cap hindered the thrust producing mechanism that conveys the generated forces in the PE to the copper frustum. And/or the melted nylon was hogging all the RF energy in the PE discs due to its higher dissipation factor in its semiliquid state. Either way it looks like there is a high E-field volume where this center nylon bolt hangs out while running in the TM212 resonant mode. Too bad Teflon bolts are so weak even in comparison to the nylon, for its dissipation factor is at least two orders of magnitude lower than the nylon's.
Best, Paul M.
I have some new observations and theory. I lifted the first picture from the Aug. '14 paper, which shows the linear displacement sensor. This device tracks the position of a reflected laser dot on a CMOS image sensor. This is usually done by calculating the center of luminance of the laser dot; a measurement that has an accuracy of a small fraction of the width of a pixel. The second picture describes a typical LDS that has sub-micron accuracy.
The only control or "NULL" experiment described in the Aug. 14 paper related to the Eagleworks device was when the dummy load was used instead of sending RF into the cavity. This of course shields the RF very well. The dummy load is 50 Ohms and so the SWR is 1:1. However when the cavity is loaded and the dielectric material is inside the cavity it's possible the SWR is much higher. This would result in RF being reflected back to the amplifier and being radiated from the shield of the RF cable. This is what happens when the SWR is not 1:1. It's possible this RF noise is interfering with the LDS. When the dielectric is not inside the cavity the SWR is lower so no interference takes place. This theory agrees with the results of the cannae test as well.
The last picture, also from the Aug. '14 paper shows a negative slope on the baseline position ( no thrust) after each RF pulse. The first one appears to level off just before the final RF pulse. After that pulse it heads down again. I believe the thermally induced change in the CoM of the emdrive causes the balance arm to rotate. This very slight rotation reduces the reflection distance for the laser beam.
Glad to see people still attempting to come up with null-thrust ideas on here. ;) How does this one account for the measured loss of thrust when the PTFE disk in the resonator cavity came loose after the nylon support bolt melted?
It's to bad that we can't find a way that one of the little known or unknown solutions to Maxwell's equations can cause a momentum.There is obviously momentum in electromagnetic waves. There are also some little known electromagnetic effects that create torque.
Unless of course it is surface electrons excited by the high power resonant RF, tunnelling through the 35 micron copper ends.Yes, and many other things may happen were not tested nor even proposed. I wonder how people can know that a lot of energy is pumped in this device and imagine nothing will get out. At the very least thermal effects should happen. Testing it in (near) vacuum doesn't eliminate the thermal hypothesis. Even Pioneer's acceleration that was due to thermal effects after all: http://spectrum.ieee.org/aerospace/astrophysics/finding-the-source-of-the-pioneer-anomaly
I have some new observations and theory. I lifted the first picture from the Aug. '14 paper, which shows the linear displacement sensor. This device tracks the position of a reflected laser dot on a CMOS image sensor. This is usually done by calculating the center of luminance of the laser dot; a measurement that has an accuracy of a small fraction of the width of a pixel. The second picture describes a typical LDS that has sub-micron accuracy.
Displacement of the pendulum arm is measured via a Linear Displacement Sensor (LDS). The primary LDS components consist of a combined laser and optical sensor on the fixed structure and a mirror on the pendulum arm. The LDS laser emits a beam which is reflected by the mirror and subsequently detected by the optical sensor. The LDS software calculates the displacement (down to the sub-micrometer level) based upon the beam reflection time. Prior to a test run data take, the LDS is positioned to a known displacement datum (usually 500 micrometers) via mechanical adjustments to its mounting platform. Gross adjustments are performed via set screws. Fine adjustments are performed using manually - operated calibrated screw mechanisms and a remotely controlled motorized mechanism that can be operated with the chamber door closed and the chamber at vacuum. The remote adjustment capability is necessary since the LDS datum will change whenever a change to the test facility environment affects the roll - out table or the chamber – e.g., whenever the chamber door is closed or latched and whenever the chamber is evacuated. Once the LDS displacement is adjusted in the final test environment, further adjustment between test run data takes is usually not required.
The only control or "NULL" experiment described in the Aug. 14 paper related to the Eagleworks device was when the dummy load was used instead of sending RF into the cavity. This of course shields the RF very well. The dummy load is 50 Ohms and so the SWR is 1:1. However when the cavity is loaded and the dielectric material is inside the cavity it's possible the SWR is much higher. This would result in RF being reflected back to the amplifier and being radiated from the shield of the RF cable. This is what happens when the SWR is not 1:1. It's possible this RF noise is interfering with the LDS. When the dielectric is not inside the cavity the SWR is lower so no interference takes place. This theory agrees with the results of the cannae test as well.
The last picture, also from the Aug. '14 paper shows a negative slope on the baseline position ( no thrust) after each RF pulse. The first one appears to level off just before the final RF pulse. After that pulse it heads down again. I believe the thermally induced change in the CoM of the emdrive causes the balance arm to rotate. This very slight rotation reduces the reflection distance for the laser beam.
frobnicat I like your diagrams, very clear.
Note that as the buckling completes the end plate will be at rest with the frustum. This means that there will be an acceleration of the end plate in the opposite direction (at some time after your diagram 4).
After the buckling completes (and all accelerations are zero) the centre of mass will not have changed. However the position of the centre of mass relative to the connection point to the torsion balance may have changed.
From this I think the torsion balance should see a force in one direction, then some time later a force in the other direction. These forces integrated should be zero.
After the buckling has completed the torsion balance should be showing no force, however as the shape of the frustum + end plate has changed the position of the external surfaces has also changed. If the force is being measured as a change in the position of the frustum then a small force would erroneously be shown (I don't think this is the case, but something to check in the experimental set-ups).
I have calculated the variables that govern which way the circular plate will buckle....I like your drawings with the buckled condition idealized as a beam with three hinges: one hinge at the center and a hinge at each end. :)
Thank you very much for taking the time to make those drawings. :)
I should have looked at that initially. I agree with your drawing. To the extent that my prior wording disagreed with your drawing, my prior words were incorrect, when and if they referred to the thermal force Fpr.
Let's then address what happens in the opposite case that the plate instead buckles to the right:
The flat plate can theoretically buckle towards the left or towards the right (if the copper is thin enough) depending on initial imperfections. If when the buckled plate moves towards the left it gives a force towards the right then if the plate buckles towards the right it would produce a force towards the left, in the same direction as the EM Drive's motion, do you agree?.
Then, if this buckling analysis is correct, it gives transient force that is towards the left when the plate buckles towards the right and it gives a transient force to the right when the plate buckles towards the left.
Now I have to give further thought to which direction the plate buckles when heated. The real plate has a neutral surface that is not at the middle of the cross-section. It is really a bi-material thermostat: with the epoxy expanding much more than the very thin copper coating. If this unsymmetric laminate would be exposed to a uniform temperature it would expand towards the outside, producing a force towards the left, like the EM Drive force. The question is what happens under the superposed thermal gradient through the thickness. The IR Camera shows very pronounced heating on the outside surface....
Therefore, since the bimaterial thermal bending is either non-existent (according to Leiton-Germany properties) or completely negigible (according to Wikipedia thermal expansion properties for FR4), it is obvious that buckling of the circular plate will be governed by initial imperfections.I have calculated the variables that govern which way the circular plate will buckle....I like your drawings with the buckled condition idealized as a beam with three hinges: one hinge at the center and a hinge at each end. :)
Thank you very much for taking the time to make those drawings. :)
I should have looked at that initially. I agree with your drawing. To the extent that my prior wording disagreed with your drawing, my prior words were incorrect, when and if they referred to the thermal force Fpr.
Let's then address what happens in the opposite case that the plate instead buckles to the right:
The flat plate can theoretically buckle towards the left or towards the right (if the copper is thin enough) depending on initial imperfections. If when the buckled plate moves towards the left it gives a force towards the right then if the plate buckles towards the right it would produce a force towards the left, in the same direction as the EM Drive's motion, do you agree?.
Then, if this buckling analysis is correct, it gives transient force that is towards the left when the plate buckles towards the right and it gives a transient force to the right when the plate buckles towards the left.
Now I have to give further thought to which direction the plate buckles when heated. The real plate has a neutral surface that is not at the middle of the cross-section. It is really a bi-material thermostat: with the epoxy expanding much more than the very thin copper coating. If this unsymmetric laminate would be exposed to a uniform temperature it would expand towards the outside, producing a force towards the left, like the EM Drive force. The question is what happens under the superposed thermal gradient through the thickness. The IR Camera shows very pronounced heating on the outside surface....
Using S. Timoshenko's classic solution to the bimaterial thermal expansion problem (Journal of the Optical Society of America, JOSA, Vol. 11, Issue 3, pp. 233-255 (1925) ) the radius of curvature can be expressed as:
radiusOfCurvature = (t1+t2)*(3(1+m)+(1+m*n)(m^2 +1/(m*n)))/(6*deltaAlpha*deltaT*((1+m)^2))
where I have expressed the following variables as non-dimensional ratios (allowing use of any consistent system of units, and revealing the important parameters, instead of the expression in Wikipedia that is awkwardly expressed in dimensional units, and expressed for the curvature instead of its reciprocal):
m=t1/t2 Thickness ratio
n=E1(1-nu1^2)/(E2(1-nu2^2)) Plate stiffness-ratio
and the differences in thermal expansion and temperature:
deltaAlpha=alpha2 - alpha1
deltaT=T - To
t1 and t2 are the thicknesses of the layers
E1 and E2 are the Young's modulii
nu1 and nu2 are the Poisson's ratios
From Paul March we know:
t1=0.00138 inches
t2=0.063 inches
the material "1" is copper
Wikipedia and Engineering Toolbox give E1=17*10^6 psi
Wikipedia, NBS (Hidnert &Krider's classic article) and Engineering Toolbox give alpha1= 17*10^(-6) 1/degK
and Wikipedia gives nu1=0.33
and that the material "2" is FR4
The following references give:
Wikipedia
ECW = 3*10^6 psi alphaCW= 14*10^(-6) 1/degK nuLW=0.136
ELW = 3.5*10^6 psi alphaLW= 12*10^(-6) 1/degK nuCW=0.118
P-M Services (UK)
alphaCW= 15*10^(-6) 1/degK
alphaLW= 11*10^(-6) 1/degK
Leiton (Germany)
alphaCW= 17*10^(-6) 1/degK
alphaLW= 12*10^(-6) 1/degK
It is trivial to show that the sign of the curvature (which way the plate is going to buckle) is governed only by the difference in thermal expansion coefficients between the two layers.
Bimaterial thermal bending will take place along the anisotropic in-plane direction with the highest thermal expansion and lowest modulus. It is obvious that this is the CW direction.
It is immediately obvious, that using Leiton's (Germany) coefficient of thermal expansions, the copper/FR4 laminate circular plate will not experience any bimaterial bending whatsoever because according to Leighton alphaCW of FR4 is exactly the same as the universally accepted alpha1 of copper.
The thermal IR camera shows temperature readings ranging from below 79 deg F to a concentrated maximum at certain small spots of 94.3 deg F.
Using Wikipedia's properties, the plate will experience an extremely small amount of bimaterial bending towards the inside, for a temperature increase from 68 deg F to 79 deg F, with a huge radius of curvature exceding 7000 inches (practically flat, in relation to the thickness of only 0.064 inches).
Also, using Wikipedia's properties, the plate will experience an extremely small amount of bimaterial bending towards the inside, for a temperature increase from 68 deg F to 94.3 deg F, with a huge radius of curvature exceeding 3000 inches (practically flat, in relation to the thickness of only 0.064 inches).
CONCLUSION: due to the fact that FR4 has a coefficient of thermal expansion very similar to the one of copper, and that the thickness of the copper is extremely small compared to the thickness of FR4, the circular plate will experience either no bimaterial thermal bending whatsoever, or it will be extremely small (will stay practically flat) under the measured changes in temperature. Therefore, bi-material bending due to a change in temperature is irrelevant to the buckling problem. Buckling is instead governed by the plate's initial imperfect flatness
FYIWhere was it hidden? Inquiring minds would like to know... :)
Found my Gunn Oscillator !!
FYIWhere was it hidden? Inquiring minds would like to know... :)
Found my Gunn Oscillator !!
While looking into the tunnelling of electrons through a barrier, I observe that the mathematics for tunnelling of electrons is very similar to the mathematics presented for propagation evanescent waves through a restriction in an RF wave-guide. See page 15, here http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf (http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf) for evanescent wave propagation and sheet 8, here http://tuttle.merc.iastate.edu/ee439/topics/tunneling.pdf (http://tuttle.merc.iastate.edu/ee439/topics/tunneling.pdf) for tunnelling of electrons through a barrier. (I would paste the math here, but both papers are PDF's, so I can't.)Their magnetic properties, for example, are opposite: Copper is (weakly) diamagnetic while Aluminum is (weakly) paramagnetic.
I guess I shouldn't be surprised that the math is similar, if not the same, as tunnelling electrons are evanescent matter waves so the math should be similar. The big difference in the two math formulations is that the author of the first paper, evanescent wave propagating through a restriction in the wave guide, relies on extended special relativity to keep the exp (+term) in the wave equation while the author of the electron tunnelling paper relies on a physical observation to retain that term.
This brings up a question. "Since we are concerned with the mass of the thruster, why isn't it made from a light metal, aluminium for example?" The work function of aluminium is very close to that of copper, is all metals. Granted that aluminium oxidized when exposed to air so that its work function more than doubles after exposure, but a very thin layer of gold electro deposited on both sides would eliminate that problem with the result of a much less massive thruster.
Can anyone suggest a reason that an aluminium cavity would not work?
What relative magnetic permeability did you input into MEEP for copper? Did you input a value less than one?
Is Maxima a descendant of Macsyma? Are they competing with Mathematica and Maple ?QuoteWhat relative magnetic permeability did you input into MEEP for copper? Did you input a value less than one?
Unfortunately I don't have a Drude model for copper at 2 GHz. We are cautioned in the meep literature that meep becomes unstable for magnetic permeability less than, or very much less than 1. I'm still using perfect metal and thick sheets at that. It's the computer resolution issue still, not enough memory and not enough CPU.
Thickness of 0.002 * height, or 0.002 * 9 inches = 0.018 inches is the best I can do in under a day of CPU time.
And FYI, I went ahead and calculated the probability of an electron tunnelling through the thin copper (I used Maxima) and found the probability to be 0.0. I guess no one is surprised by that result. That result could be off by a few orders of magnitude, but then what is 0E10? :)
It's to bad that we can't find a way that one of the little known or unknown solutions to Maxwell's equations can cause a momentum.There is obviously momentum in electromagnetic waves. There are also some little known electromagnetic effects that create torque.
Unless of course it is surface electrons excited by the high power resonant RF, tunnelling through the 35 micron copper ends.Quoting @JPLeRouzic
Yes, and many other things may happen were not tested nor even proposed. I wonder how people can know that a lot of energy is pumped in this device and imagine nothing will get out. At the very least thermal effects should happen. Testing it in (near) vacuum doesn't eliminate the thermal hypothesis. Even Pioneer's acceleration that was due to thermal effects after all: http://spectrum.ieee.org/aerospace/astrophysics/finding-the-source-of-the-pioneer-anomaly
Another thing that strikes me is that people search for a unique cause explaining everything, which is a bit unlikely.
One last thought: If a simulator shows results, build this device and publish results in a mainstream conference. Interesting things may happen ;-)
Is Maxima a descendant of Macsyma? Are they competing with Mathematica and Maple ?
(I remember using Macsyma at MIT in the late 1970's :) )
Stainless Steel 304L (the material of the vacuum chamber) is weakly paramagnetic (the opposite of copper). What relative magnetic permeability did you input into MEEP for the StSt 304L for the chamber? Did you input a value greater than one? Did you report to us that value? I don't recall.
...Are you planning to conduct an experiment with a dielectric inside a cylindrical cavity?
I've determined that both the 10 and 16 mil are too thin to serve as frustum walls, thus they will become end caps.
(https://lh3.googleusercontent.com/FHha_JWui320K0ZM7Zt_GA8MSaKKbn6LFjhuCU7Ul6QHwbdFXRgp60qOJ_SVm026udzIJw=w1566-h632)
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
...
...Are you planning to conduct an experiment with a dielectric inside a cylindrical cavity?
I've determined that both the 10 and 16 mil are too thin to serve as frustum walls, thus they will become end caps.
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
...
Somebody should do so!
Such an experiment would disprove all the theories with formulas advanced so far. All the formulas (Shawyer's, McCulloch and Notsosureofit...) give zero thrust if both diameters are the same.
Notsosureofit:
Your equation gives zero thrust for a cylinder (constant diameter along its length). Thus, according to your formula a cylinder will give no thrust, only a geometrical object with decreasing diameter will (ditto for Shawyer's and McCulloch's)
But your formula does not explicitly include a dielectric.
QUESTION: would your line of thinking also give zero thrust for a cylinder with an inserted dielectric at one end of the cavity with constant, homogeneous, isotropic dielectric properties ? (With no nonlinearities)
...Are you planning to conduct an experiment with a dielectric inside a cylindrical cavity?
I've determined that both the 10 and 16 mil are too thin to serve as frustum walls, thus they will become end caps.
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
...
Somebody should do so!
Such an experiment would disprove all the theories with formulas advanced so far. All the formulas (Shawyer's, McCulloch and Notsosureofit...) give zero thrust if both diameters are the same.
Yes, a cylinder experiment absolutely has to be done.
Notsosureofit:
Your equation gives zero thrust for a cylinder (constant diameter along its length). Thus, according to your formula a cylinder will give no thrust, only a geometrical object with decreasing diameter will (ditto for Shawyer's and McCulloch's)
But your formula does not explicitly include a dielectric.
QUESTION: would your line of thinking also give zero thrust for a cylinder with an inserted dielectric at one end of the cavity with constant, homogeneous, isotropic dielectric properties ? (With no nonlinearities)
Presumably no, as long as you have frequency dispersion along the axis you should predict a force.
Edit: But it adds complication to the formula in that the second term doesn't cancel out.
Are you planning to conduct an experiment with a dielectric inside a cylindrical cavity?
Somebody should do so!
Such an experiment would disprove all the theories with formulas advanced so far. All the formulas (Shawyer's, McCulloch and Notsosureofit...) give zero thrust if both diameters are the same.
Notsosureofit:
Your equation gives zero thrust for a cylinder (constant diameter along its length). Thus, according to your formula a cylinder will give no thrust, only a geometrical object with decreasing diameter will (ditto for Shawyer's and McCulloch's)
But your formula does not explicitly include a dielectric.
QUESTION: would your line of thinking also give zero thrust for a cylinder with an inserted dielectric at one end of the cavity with constant, homogeneous, isotropic dielectric properties ? (With no nonlinearities)
Presumably no, as long as you have frequency dispersion along the axis you should predict a force.
Edit: But it adds complication to the formula in that the second term doesn't cancel out.
Since your existing formula:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
gives NT=0 (zero thrust force) for Rs=Rb (a cylinder), just like Shawyer's and McCulloch's also go to zero for that case, then my understanding from your reply is that this formula is a simplification and that there are terms you neglected that do not go to zero for a cylinder.
Do you know the 2nd order term that will still be finite for Rs=Rb (a cylinder) ?
Or is the issue deriving an equation for the dispersion including the dielectric?
Since there is really no proven theory of how would an EM Drive generate thrust in space, thereby apparently violating the law of conservation of momentum, and we are still debating whether the experimental measurements are an artifact, the best way to cut to the chase is to test an EM Drive made of Aluminum, and to also test an iron (or a material coated with an interior thin film of Metglas) for the big flat end.
Are you planning to conduct an experiment with a dielectric inside a cylindrical cavity?
Somebody should do so!
Such an experiment would disprove all the theories with formulas advanced so far. All the formulas (Shawyer's, McCulloch and Notsosureofit...) give zero thrust if both diameters are the same.
Before removing the internal dielectric, Shawyer considered a cylindrical EmDrive, in which a conical dielectric would be mandatory for thrust. See his 1990 UK Patent Application GB2229865 "Electrical Propulsion Unit for Spacecraft", attached below.
Seems like wherever we go with this project, Shawyer has already been there - and like as not, built a test model. Given that, is there any way to bring his reasoning/math in line with conventional physics, or do they remain fundamentally irreconcilable? I keep getting the impression he's on to something major, but consistently fails to communicate that 'something' in a coherent manner.Well, Edison was one of the greatest inventors. He was completely self-taught (with visits to the Cooper Union). Edison was born only 16 years after Maxwell. Edison was responsible for some of the greatest electromagnetic inventions ever, yet he was not a theoretical physicist like Maxwell or Hertz. Who was the inventor? Edison or Maxwell?. Why should Shawyer be the one expected to explain the physics of why it works (if it does work)?
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
I've determined that both the 10 and 16 mil are too thin to serve as frustum walls, thus they will become end caps.
(https://lh3.googleusercontent.com/FHha_JWui320K0ZM7Zt_GA8MSaKKbn6LFjhuCU7Ul6QHwbdFXRgp60qOJ_SVm026udzIJw=w1566-h632)
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh6.googleusercontent.com/X8z7ACoAfs4KhtbcY2o7xCdzx0sTbIevAqhrVKmsst-dPVhd_MauiiDh6V5ZrQkd9bIkhw=w1549-h632)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Again thanks to @Paul March for providing the dimensions for his DUT over at Eagleworks:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327467#msg1327467
Well, Edison was one of the greatest inventors. He was completely self-taught (with visits to the Cooper Union). Edison was born only 16 years after Maxwell. Edison was responsible for some of the greatest electromagnetic inventions ever, yet he was not a theoretical physicist like Maxwell or Hertz. Who was the inventor? Edison or Maxwell?. Why should Shawyer be the one expected to explain the physics of why it works (if it does work)?
The majority of contributors to this thread say that what's needed are much more experiments: mainly to confirm that the thrust is real or to nullify it, by verifying the experiments at another NASA center (Glenn or JPL) and a univeristy (John Hopkins, for example) and put this EM Drive phenomena to bed, or continue its engineering progress. Actually a number of contributors are planning their own experiments and have shown photographs of their progress. The number of experiments conducted for the EM Drive and the R&D budget are infinitesimal compared with the number of experiments regularly conducted in R&D projects both commercial, academic or government agency and in comparison with normal R&D budgets. Not a single experiment has been conducted at a US or European University. Here are a number of experiments that could be conducted: cylindrical cavity without dielectric, cylindrical cavity with cylindrical dielectric, cylindrical cavity with conical dielectric, truncated cone with one end made of cast iron, truncated cone made with one end internally coated with thin film of Metglas, truncated cone made with Aluminum instead of copper, comparison of excitation produced by Gunn diode, magnetron, etc.; examination of thrust force vs. cone angle of truncated cone, examination of thrust force in a cone (untruncated) cavity. Should I continue?QuoteWell, Edison was one of the greatest inventors. He was completely self-taught (with visits to the Cooper Union). Edison was born only 16 years after Maxwell. Edison was responsible for some of the greatest electromagnetic inventions ever, yet he was not a theoretical physicist like Maxwell or Hertz. Who was the inventor? Edison or Maxwell?. Why should Shawyer be the one expected to explain the physics of why it works (if it does work)?
People here and elsewhere say a coherent theory is needed in order to advance with this project.
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What do you mean? It's known since 19th century there is momentum in electromagnetic waves. It's not something new.It's to bad that we can't find a way that one of the little known or unknown solutions to Maxwell's equations can cause a momentum.There is obviously momentum in electromagnetic waves. There are also some little known electromagnetic effects that create torque.
http://arxiv.org/abs/0807.1310
Quoting @Aero5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.QuoteUnless of course it is surface electrons excited by the high power resonant RF, tunnelling through the 35 micron copper ends.Quoting @JPLeRouzicQuoteYes, and many other things may happen were not tested nor even proposed. I wonder how people can know that a lot of energy is pumped in this device and imagine nothing will get out. At the very least thermal effects should happen. Testing it in (near) vacuum doesn't eliminate the thermal hypothesis. Even Pioneer's acceleration that was due to thermal effects after all: http://spectrum.ieee.org/aerospace/astrophysics/finding-the-source-of-the-pioneer-anomaly
Another thing that strikes me is that people search for a unique cause explaining everything, which is a bit unlikely.
One last thought: If a simulator shows results, build this device and publish results in a mainstream conference. Interesting things may happen ;-)
There are absolutely thermal effects. For every watt pumped in, you get that much heat out as IR. An RF dummy load is an efficient converter of RF to heat. The systemic effects slide with the dummy load attached is the control for heat. Thermal artifacts were a major area of exploration in both threads. Paul March provided lots of data to show that thermal effects were extensively studied over at Eagleworks. There's a thermal analysis on this thread, one of many indications that heat was controlled for: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326997#msg1326997 Plus the math that has been done numerous times for a photon rocket doesn't add up. So the vacuum did eliminate the thermal hypothesis.
Great find and thanks :) for bringing it to our attention, this is the first time I see this patent.
Very thought provoking, and interesting in its own right.
I note that Shawyer's patent was file in 1988 !, that's 27 years ago !
This man has been working at this for a long, long time
An electronic propulsion engine that creates a propulsive force or thrust using forces or electrostatic electromagnetic forces, with an effect that is similar to the thrust of a jet or rocket engine. Forces are generated using electromagnets or capacitor plates that are separated by dielectric spacer cores and are operated with two modulated currents. The two modulated currents are synchronized, but with a relative phase such that the forces on the two magnets or capacitor plates are not balanced. Included are techniques to reduce circuit impedance and control field dispersion, such as tuned LCR circuits, dielectric core materials between the magnets or capacitor plates, and RF superconductors result in high propulsion efficiencies. The system operates at RF frequencies and can also be used as a communication device.
Hi. Newcomer here but I have been following since thread 1....Welcome to this thread :)
...To my knowledge Roger Shawyer filed 4 patent applications related to the EmDrive, here they are attached at the bottom of this message....
So the vacuum did eliminate the thermal hypothesis....
5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.
Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects.
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
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Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?
The experimenters may contemplate using the simple Cavendish balance as done by Cavendish in his experiment performed more than 200 years ago (in 1797–98) http://en.wikipedia.org/wiki/Cavendish_experiment.How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?
- Roger Shawyer achieved 174 mN of thrust at an input power of 450 W in 2010 (he then operated its engine up to 600 W but thrust levels are not known fort that power).
- Chinese NWPU achieved 720 mN @ 2500 W in 2010.
- Eagleworks achieved 116 µN @ 17 W in 2014.
So if you're gonna try an EmDrive at home, you'd better feed it with at least severals hundred of watts of electric power to be able to measure tens to hundreds of millinewtons. Staying below 100 W seems to produce thrusts in the micronewton range, way too low and something only a dedicated lab like Eagleworks can detect with expensive apparatus. At that level you detect any low-frequency vibrations like small seismic events. Indeed you noticed in the paper that Eagleworks used an isolated test rig from the Apollo program era with an extremely sensitive torsion pendulum, and on windy days they were able to detect the waves from the Gulf of Mexico, about 25 miles southeast of JSC… This low-power experiment was intended for a specific purpose: test the EmDrive in a hard vacuum. Only a small device with a compact and light onboard power amplifier could be tested, hence the very low power used compared to previous experiments by Shawyer and the Chinese.
The Chinese pursue a different path: they try to brutally produce the maximum thrust available with cheap but high power magnetrons. This way they cannot eliminate convection current or test their drive in a hard vacuum, but they can show the thrust achieved is too high to be accounted only for trivial reasons. Besides they showed the engine could compete with modern ion thrusters and perhaps one day overtake them.
You can also let the test article rotate. But it's not easy. Shawyer conducted such dynamic tests on a rotating rig. The whole device weighted 100 kg, comprising the thruster and a cooling system mounted on a beam, supported on a low-friction air bearing. The device reportedly consumed 300 W of power and produced a force of 96.1 mN, a maximum speed of 2 cm/s over 185 cm during testing in October 2006. See this 2007 article by Eureka magazine (http://www.eurekamagazine.co.uk/design-engineering-features/technology/no-propellant-drive-prepares-for-space-and-beyond/9657/) who covered the story, and this article from Wired (http://www.wired.com/2008/10/video-impossibl/) the year after, which displays a video where you can see the mammoth.
Interesting thing to note: Shawyer claims the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period where it does not move; thus according to him eliminating possible spurious forces.
We'd need some data of tests made with high-Q superconducting cavities. But only Cannae LCC briefly talked about such test results before shutting down their web site.
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Interesting thing to note: Shawyer claims the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period where it does not move; thus according to him eliminating possible spurious forces.
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You are indeed right about the two thermal effects you mention, and I don't want to be pushed into territories that I don't master and that were not the subject of my initial post.So the vacuum did eliminate the thermal hypothesis....
5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.
Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects.
@Mulletron must have meant "So the vacuum did eliminate the [natural convection] thermal hypothesis" . He wrote "thermal hypothesis" without the words "natural convection" because he thought that it was obviously understood he was referring to convection in the context he was discussing: what is the difference between ambient pressure and 5*10-6 Torr. Obviously this pressure makes a huge difference for natural convection currents, as a trivial calculation can show that 5*10-6 Torr vacuum does eliminate the natural convection hypothesis that was advanced in most media (including Prof. Baez's blog) as the most likely explanation for the measurements. @Frobnicat, was proposing the thermal convection hypothesis as a possible artifact, and he worked some equations in Thread 1. I do not recall @Frobnicat objecting to a 5*10-6 Torr vacuum nullifying the hypothesis of natural thermal convection from the EM Drive being able to produce the measured forces.
Concerning <<Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects>>, yes the Pioneer anomaly was successfully explained by a team of JPL engineers/scientists on the basis of thermal radiation effects (not natural convection thermal effects).
Thermal radiation, an entirely different (from convection) means of thermal transport, will take place even in a perfect vacuum, as thermal radiation is electromagnetic radiation and therefore does not need a gas or a fluid as a transport medium. On the other hand natural convection is completely dependent on fluid or gas medium to carry it, and without a fluid or a gas, there cannot be any thermal convection. Thermal convection involves fluid advection.
Radiative heat transfer is the only form of heat transfer that can take place in a vacuum. Radiative heat transfer depends on the difference between the fourth power of the temperatures between the radiating surface and the irradiated surface, the surface areas and the emissivities of the radiating and irradiated surfaces and the Stefan–Boltzmann constant . It may be important for the Pioneer anomaly: an extremely small effect comprising an acceration towards the Sun, of only 8.74×10^(−10) m/s^2, due to asymmetrical radiation of heat from the Radioisotope thermoelectric generators or from the spacecraft electronics reflecting from the back of the spacecraft's dish-like main antenna, causing a recoil like sunlight striking a solar sail.
But in the case of the EM Drive, how much does the temperature difference between radiated and irradiated surfaces have to be to to justify the measured thrust forces ?
For a third opinion on this matter, it will be interesting to hear comments from @frobnicat (who is also from France :) ?), using Frobnicat's thermal convection calculations (discussed in Thread 1) using an atmosphere at 5*10-6 Torr .You are indeed right about the two thermal effects you mention, and I don't want to be pushed into territories that I don't master and that were not the subject of my initial post.So the vacuum did eliminate the thermal hypothesis....
5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.
Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects.
@Mulletron must have meant "So the vacuum did eliminate the [natural convection] thermal hypothesis" . He wrote "thermal hypothesis" without the words "natural convection" because he thought that it was obviously understood he was referring to convection in the context he was discussing: what is the difference between ambient pressure and 5*10-6 Torr. Obviously this pressure makes a huge difference for natural convection currents, as a trivial calculation can show that 5*10-6 Torr vacuum does eliminate the natural convection hypothesis that was advanced in most media (including Prof. Baez's blog) as the most likely explanation for the measurements. @Frobnicat, was proposing the thermal convection hypothesis as a possible artifact, and he worked some equations in Thread 1. I do not recall @Frobnicat objecting to a 5*10-6 Torr vacuum nullifying the hypothesis of natural thermal convection from the EM Drive being able to produce the measured forces.
Concerning <<Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects>>, yes the Pioneer anomaly was successfully explained by a team of JPL engineers/scientists on the basis of thermal radiation effects (not natural convection thermal effects).
Thermal radiation, an entirely different (from convection) means of thermal transport, will take place even in a perfect vacuum, as thermal radiation is electromagnetic radiation and therefore does not need a gas or a fluid as a transport medium. On the other hand natural convection is completely dependent on fluid or gas medium to carry it, and without a fluid or a gas, there cannot be any thermal convection. Thermal convection involves fluid advection.
Radiative heat transfer is the only form of heat transfer that can take place in a vacuum. Radiative heat transfer depends on the difference between the fourth power of the temperatures between the radiating surface and the irradiated surface, the surface areas and the emissivities of the radiating and irradiated surfaces and the Stefan–Boltzmann constant . It may be important for the Pioneer anomaly: an extremely small effect comprising an acceration towards the Sun, of only 8.74×10^(−10) m/s^2, due to asymmetrical radiation of heat from the Radioisotope thermoelectric generators or from the spacecraft electronics reflecting from the back of the spacecraft's dish-like main antenna, causing a recoil like sunlight striking a solar sail.
But in the case of the EM Drive, how much does the temperature difference between radiated and irradiated surfaces have to be to to justify the measured thrust forces ?
However I believe (and in writing this, I do something stupid :) ) that thermal convection means implicitly that the mean molecular free path is negligible so thermal convection anyway can't exist at all at this pressure.
However that doesn't means we should stop here. At 5*10-6 Torr there are still 5*10^11 molecules per cm3 and mean free path is in the 5m range. I did rule of thumb calcs (that indeed I will never publish 8)), and the thrust is still in the 5-10 µNewton range. My calcs are obviously wrong but indicate that one cannot conclude easily there is absolutely no thermal effect possible at 5*10-6 Torr.
So the vacuum did eliminate the thermal hypothesis....
5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.
Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects.
@Mulletron must have meant "So the vacuum did eliminate the [natural convection] thermal hypothesis" . He wrote "thermal hypothesis" without the words "natural convection" because he thought that it was obviously understood he was referring to convection in the context he was discussing: what is the difference between ambient pressure and 5*10-6 Torr. Obviously this pressure makes a huge difference for natural convection currents, as a trivial calculation can show that 5*10-6 Torr vacuum does eliminate the natural convection hypothesis that was advanced in most media (including Prof. Baez's blog) as the most likely explanation for the measurements. @Frobnicat, was proposing the thermal convection hypothesis as a possible artifact, and he worked some equations in Thread 1. I do not recall @Frobnicat objecting to a 5*10-6 Torr vacuum nullifying the hypothesis of natural thermal convection from the EM Drive being able to produce the measured forces.
...
Concerning <<Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects>>, yes the Pioneer anomaly was successfully explained by a team of JPL engineers/scientists on the basis of thermal radiation effects (not natural convection thermal effects).
Thermal radiation, an entirely different (from convection) means of thermal transport, will take place even in a perfect vacuum, as thermal radiation is electromagnetic radiation and therefore does not need a gas or a fluid as a transport medium. On the other hand natural convection is completely dependent on fluid or gas medium to carry it, and without a fluid or a gas, there cannot be any thermal convection. Thermal convection involves fluid advection.
Radiative heat transfer is the only form of heat transfer that can take place in a vacuum. Radiative heat transfer depends on the difference between the fourth power of the temperatures between the radiating surface and the irradiated surface, the surface areas and the emissivities of the radiating and irradiated surfaces and the Stefan–Boltzmann constant . It may be important for the Pioneer anomaly: an extremely small effect comprising an acceration towards the Sun, of only 8.74×10^(−10) m/s^2, due to asymmetrical radiation of heat from the Radioisotope thermoelectric generators or from the spacecraft electronics reflecting from the back of the spacecraft's dish-like main antenna, causing a recoil like sunlight striking a solar sail.
But in the case of the EM Drive, how much does the temperature difference between radiated and irradiated surfaces have to be to to justify the measured thrust forces ?
I agree.So the vacuum did eliminate the thermal hypothesis....
5*10-6 Torr is hardly a vacuum good enough to eliminate the thermal hypothesis. That's what you encounter at 1000 km high or so.
Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects.
@Mulletron must have meant "So the vacuum did eliminate the [natural convection] thermal hypothesis" . He wrote "thermal hypothesis" without the words "natural convection" because he thought that it was obviously understood he was referring to convection in the context he was discussing: what is the difference between ambient pressure and 5*10-6 Torr. Obviously this pressure makes a huge difference for natural convection currents, as a trivial calculation can show that 5*10-6 Torr vacuum does eliminate the natural convection hypothesis that was advanced in most media (including Prof. Baez's blog) as the most likely explanation for the measurements. @Frobnicat, was proposing the thermal convection hypothesis as a possible artifact, and he worked some equations in Thread 1. I do not recall @Frobnicat objecting to a 5*10-6 Torr vacuum nullifying the hypothesis of natural thermal convection from the EM Drive being able to produce the measured forces.
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My specific proposition at the time was a pressure difference build-up between inside cavity and outside, enough to "jet" supposedly warmed air through small apertures of the cavity. I recall having said about 5 month ago I would give a definite answer within 2 month (so much for my credibility with deadlines). This specific "warm jet" hypothesis would have been easily nullified even by a very more modest rough vacuum level of a few Torr. So this specific hypothesis is now ruled out, and I'm glad the experimental progress at Eaglworks outpaced my episodic armchair scientist investment on that matter :D
For anything pressure related (even complex anisotropic molecular flow like in a Crookes radiometer effect) a characteristic value would be an extreme case of a completely asymmetric pressure difference around 5e-6 Torr = 6.65e-4 Pa on a surface of 11'' diameter = 6.13e-2 m² (roughly, cross section of the frustum) that yields about 41µN. Unfortunately still in the ballpark of the signal... so maybe hardcore sceptics could still require 2 orders of magnitude better vacuum, just to be sure... (edit : I see JPLeRouzic reach similar conclusion)
Anyway, it's clear that it becomes difficult to find remaining thermo-aerodynamic effects that would need better than 5e-6 Torr to be ruled out : this is good enough to put possible asymmetric gas flow effects much below the observed signal.Quote
Concerning <<Pioneer lives in a vacuum *one million* times better that 5*10-6 Torr and there are still thermal effects>>, yes the Pioneer anomaly was successfully explained by a team of JPL engineers/scientists on the basis of thermal radiation effects (not natural convection thermal effects).
Thermal radiation, an entirely different (from convection) means of thermal transport, will take place even in a perfect vacuum, as thermal radiation is electromagnetic radiation and therefore does not need a gas or a fluid as a transport medium. On the other hand natural convection is completely dependent on fluid or gas medium to carry it, and without a fluid or a gas, there cannot be any thermal convection. Thermal convection involves fluid advection.
Radiative heat transfer is the only form of heat transfer that can take place in a vacuum. Radiative heat transfer depends on the difference between the fourth power of the temperatures between the radiating surface and the irradiated surface, the surface areas and the emissivities of the radiating and irradiated surfaces and the Stefan–Boltzmann constant . It may be important for the Pioneer anomaly: an extremely small effect comprising an acceration towards the Sun, of only 8.74×10^(−10) m/s^2, due to asymmetrical radiation of heat from the Radioisotope thermoelectric generators or from the spacecraft electronics reflecting from the back of the spacecraft's dish-like main antenna, causing a recoil like sunlight striking a solar sail.
But in the case of the EM Drive, how much does the temperature difference between radiated and irradiated surfaces have to be to to justify the measured thrust forces ?
Very clear.
For the last question, I would be tempted to say : temperatures needing 300 times the actual operating power of the system, since the force/power ratios are ~300 times better than a photon rocket.
Unless the space between the frustum and the vacuum chamber's walls could amplify the effect by bouncing hotter IR photons around a few times and make high temperature, high radiation pressure "traps". IR photons are emitted around all the time, but at thermal equilibrium those radiative pressures have equal contribution on all side of an object in the bath. Anyone knows the typical reflectivity of more or less polished metals in thermal IR ? That would put an upper bound on the "boost" factor compared to the photon rocket equivalent thrust, likely much below 300.
@ RODAL
Still have question about the Shawyer "Demo" cavity w/ 174mN. What are the current estimates of the cone dimensions, frequency (3.85GHz?), and Q (6000 est?). When I put in TM02 and 450W, I get 174.8microN, rather than the 174milliN reported. I would like to recheck those numbers.
Even w/ Q=45000, I need to get X up around (65 Very high mode) to get those numbers. Is that possible w/ 3.85GHz ??
Thanks
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Interesting thing to note: Shawyer claims the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period where it does not move; thus according to him eliminating possible spurious forces.
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That's very interesting stuff. Thank you for bringing it up.
Do you have a reference as to where Shawyer made that interesting claim?
The frequency offset curve shows that initial magnetron thermal drift ends with frequency lock. At this point, 130 secs into the test run, the velocity data shows the start of acceleration under power. The prior thermal drift period, with no acceleration, shows that the thrust is not a result of spurious thermal effects. When the power is turned off, at 210 secs, there is a coast period as the slosh effects of 5kg of coolant maintain a reduced acceleration. This is followed by the deceleration due to the friction torque. A maximum velocity of 2cm/s was achieved and a total distance of 185cm was "flown".
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Do you have a reference giving frequency, Q, power and thrust measurements for the Flight Thruster?
This is the only reference I have for data for the Flight Thruster: http://emdrive.com/flightprogramme.html, I can't find a Q reported.
The Flight thruster programme covers the design and development of a 300 Watt C Band flight thruster. This has a specified thrust of 85 mN, and a mass of 2.92Kg. Overall dimensions are 265mm diameter at the baseplate and a height of 164mm.
Development testing of the unit, up to a power of 600 W, is under way, and to date, has given a mean specific thrust of 330 mN/kW.
[…]
This is needed to ensure the input frequency matches the resonant frequency of the high Q (60,000) cavity, over the full input power range and the qualification temperature specification.
The Dynamic performance of the non superconducting Flight Test model, manufactured and tested by SPR Ltd, and described in REF 3 [N.B.: 2010 Toulouse TECHNO DIS paper] was modeled with a cavity Qu = 50,000 and Fres=3.85 GHz.
....Excellent. You are our resident expert on Shawyer's tests. We are lucky to have you on the thread :)
@ RODAL
Still have question about the Shawyer "Demo" cavity w/ 174mN. What are the current estimates of the cone dimensions, frequency (3.85GHz?), and Q (6000 est?). When I put in TM02 and 450W, I get 174.8microN, rather than the 174milliN reported. I would like to recheck those numbers.
Even w/ Q=45000, I need to get X up around (65 Very high mode) to get those numbers. Is that possible w/ 3.85GHz ??
Thanks
...With respect to the HD PE dielectric, now I see your thinking. I think you think of it as a dynamic problem, for example, if instead of the HD PE we would have an explosive inside the cavity glued to the left wall, the effect of the explosive would be to force the wall towards the left.
??? When thermal expansion displaces a part of a system relative to the rest of a system, the rest of the system will recoil. Whatever displaces a part of a system relative to the rest of the system, this displacement implies a force F_system_part. The rest of the system will recoil. Recoil is the acceleration due to the opposite force (F_part_system). An unrestrained, homogeneous, isotropic, free to expand but in one direction material, will produce a force when expanding against the wall against which it rests.
Why is it so hard to reach consensus now ?
However, thermal expansion does not work like that. There are no dynamic forces caused by a material experiencing thermal expansion such that it is free to expand. Thermal expansion is a very slow process that does not involve second order derivatives with respect to time. If a uniaxial isotropic material is glued to a wall, it will just expand without producing any force whatsoever on the wall it is glued to.
If free, it will just expand, strain = alpha *deltaT.
No stress if it is free to expand.
Can't use thermal expansion as a form of propellant-less propulsion.
For what it's worth, I don't think the given numbers (265mm base diameter and 164mm axial height) can possibly be right for the inner cavity of the thruster in the photo- not unless whatever plates that are inserted within the ends are several centimeters thick. The only way that the height is only .6188 or 62% of the base diameter is if the 265mm base diameter is measured from the widest part of the exterior of the base plate, and the height is measured from where the slope of the exterior walls flattens out on top and bottom as roughly indicated by the yellow arrows in the attached photo. If that happened to be the case, then 189mm would be the exterior diameter of the top plate.In summary, what do you think are the most likely inner dimensions?
But there's almost no way, in my humble opinion, that 265mm, 164mm and 189mm are correct for the inner cavity. Unless, again, the plates (diaelectric?) inserted inside the end plates in the inner cavity are several centimeters thick. I'm pretty confident in saying that. The distortion in the photo isn't nearly enough to account the discrepancy.
I only point this out to maybe prevent some confusion, and now retreat to my recliner and leave the real work to minds more learned than mine.
In summary, what do you think are the most likely inner dimensions?To be honest I'm a little baffled that the given numbers (265mm base and 164mm height) are so irreconcilable with the measured dimensions of the thruster in the photo. I'm pretty confident with my pixel scales. Is it possible that the dielectric plates you guys keep referring to, located within the end plates, are that thick?
For the part in blue : I don't see the qualitative difference you make between an explosive detonating on a left wall and a plastic block glued to a left wall and thermally expanding, in both cases it is thermal expansion. A material that expands is never completely free to expands, it must at least overcome its own inertia, even if slow quasi-static expansion occurs... Take for instance a slice of the material at the right of the slab, when the whole slab is heating, its distance from the left wall increase (meaning non 0 velocity), it has a mass, it was initially at velocity 0, so going from velocity 0 to some non null velocity implies an acceleration at some time, and this slice has a mass, so the rest of the slab had to push it, hence stress. The slower the process the weaker the forces, but weak is not 0. So maybe there is no leftward force of the plastic block expanding rightward during the phase of heating at constant rate if that means constant velocity of block's CoM, but at some time between start of heating and constant rate there has been a leftward force (on the wall). Likewise at some time between this phase of constant rate heating (constant expansion velocity) and stabilisation at constant position (end of movement to the right, 0 velocity again) there must be a deceleration, that is a leftward acceleration that corresponds to the block pulling the wall toward the right : if it wasn't glued it couldn't decelerate and would leave the left wall.
The integrated forces between initial static position (at 0 relative velocity) and final static position (at 0 relative velocity) will be 0, since by definition the force (kg m/s²) when integrated is the exchanged momentum (kg m/s). So yes "Can't use thermal expansion as a form of propellant-less propulsion" in the sense that it can't give long lasting momentum (deltaV) to a spacecraft. But it can lend small temporary momentum to be paid back a little later, since it can give momentary speed, it can give long lasting displacement : by integrating the momentary "bump" in momentum(t) the craft of mass M will have shifted its position by X while the moving part of mass m has moved x, with MX=-mx (in kg m units). And from this point of view, this displacement is the same whether the mass m moved distance x fast or ultra-slowly. Equalling force terms to 0 because movement is slow would fail to predict that : weak forces for long time do the same "displacement job" as strong forces for short time.
So a spacecraft A that is already at exact same velocity than spacecraft B but a few inches apart could dock to it just by shifting an inner part's mass. Obviously the mass shift can't be recycled to "inchworm" spacecraft's position again and again : to put the part at it's original position means losing the whole system's gained displacement. But the point is : that don't depend on the specifics of what makes the part move.
So what's the point ? Regardless of what exactly would make a part move relative to another in the frustum, we know that 50µN for 45s, interpreted as a slowly occurring recoil effect (ever-accelerating part), amounts for an integrated "mass displacement" of .5*50e-6*45²=0.05 kg m that is either 50 grams moving 1m, or 1kg moving 5cm, or 10kg moving 5mm. Sorry, this is a repeat.
If the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:
224mm base diameter
145mm top diameter
164mm height (given by Shawyer).
Here's the chart if anyone is interested, cluttered though it has admittedly become.
If the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:
224mm base diameter
145mm top diameter
164mm height (given by Shawyer).
Here's the chart if anyone is interested, cluttered though it has admittedly become.
Thanks! That brings that X number down to ~55. Still a very high mode, but 3.85GHz !
If the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:
224mm base diameter
145mm top diameter
164mm height (given by Shawyer).
Here's the chart if anyone is interested, cluttered though it has admittedly become.
Thanks! That brings that X number down to ~55. Still a very high mode, but 3.85GHz !
McCulloch's equation gives 148 milliNewtons for Shawyer's demo, comparing pretty well with Shawyer's reported measurements of 80 to 214 millinNewtons, see:
http://physicsfromtheedge.blogspot.com/2015/02/mihsc-vs-emdrive-data-3d.html
I understand that you need to use X=26 in your equation for Shawyer's Demo, also a high mode.
On the other's hand McCulloch's equation is off by a factor >10 for NASA Eagleworks test results.
What changes with time (very slowly, due to the low thermal diffusivity of HD PE) is the temperature.
Please, I'm not accustomed to such tools as those used for thermoacoustics. There is not enough of a life to learn all... Just applying more rudimentary reasoning : my slab of PTFE, volumetrically heated, free floating alone, would expand as much leftward than rightward. If glued to a left wall inside an heavy hull, it will expand more rightward than leftward (in the same inertial reference frame) : necessarily it means that at some time there have been a force of the wall on the slab, otherwise a solid object as a wall wouldn't have been needed to prevent the slab to expand leftward. If such wall exerted no force at all, the slab would have expanded through the wall as if it didn't existed. Ahem.
So if by "speed of thermal expansion is constant" you mean a phase when in all place there is a constant rate dT/dt, and therefore all positions are also changing at constant rate (dx/dt constant), well yes, in such phase there is no acceleration and no force. But what is going on between dT/dt = 0 and dT/dt =cst, that is between an instant where dx/dt=0 and an instant where dx/dt=cst ? Surely at some time there is a force involved. Now, maybe it's usually neglected because it is negligible for all practical purpose, but if we are to integrate µN ...
So if there is no "thermal expansion acceleration" how do you go from a state of no thermal expansion to a state of ongoing thermal expansion ? Step like ? But this step would still represent some momentum impulse...
Please define the "speed of thermal expansion" that is supposed to be constant, I don't get it.
For instance if one is heating volumetrically a mass of material at linearly growing power at constant rate P(t)=cst t, then we have a heat energy Q that goes as t², and so does temperature T, and if we assume a slow (quasi-static) rate, the material will be at length l(t)=cst + cst*t² hence ldot=velocity=cst*t hence acceleration=cst hence constant inertial force to overcome...
....
Interesting thing to note: Shawyer claims the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period where it does not move; thus according to him eliminating possible spurious forces.
....
That's very interesting stuff. Thank you for bringing it up.
Do you have a reference as to where Shawyer made that interesting claim?
Yes, it is in the same 2008 paper you have just cited in the message above this one, entitled "MICROWAVE PROPULSION – PROGRESS IN THE EMDRIVE PROGRAMME":
http://www.emdrive.com/IAC-08-C4-4-7.pdf
Where Shawyer noted:QuoteThe frequency offset curve shows that initial magnetron thermal drift ends with frequency lock. At this point, 130 secs into the test run, the velocity data shows the start of acceleration under power. The prior thermal drift period, with no acceleration, shows that the thrust is not a result of spurious thermal effects. When the power is turned off, at 210 secs, there is a coast period as the slosh effects of 5kg of coolant maintain a reduced acceleration. This is followed by the deceleration due to the friction torque. A maximum velocity of 2cm/s was achieved and a total distance of 185cm was "flown".
What changes with time (very slowly, due to the low thermal diffusivity of HD PE) is the temperature.
Please, I'm not accustomed to such tools as those used for thermoacoustics. There is not enough of a life to learn all... Just applying more rudimentary reasoning : my slab of PTFE, volumetrically heated, free floating alone, would expand as much leftward than rightward. If glued to a left wall inside an heavy hull, it will expand more rightward than leftward (in the same inertial reference frame) : necessarily it means that at some time there have been a force of the wall on the slab, otherwise a solid object as a wall wouldn't have been needed to prevent the slab to expand leftward. If such wall exerted no force at all, the slab would have expanded through the wall as if it didn't existed. Ahem.
So if by "speed of thermal expansion is constant" you mean a phase when in all place there is a constant rate dT/dt, and therefore all positions are also changing at constant rate (dx/dt constant), well yes, in such phase there is no acceleration and no force. But what is going on between dT/dt = 0 and dT/dt =cst, that is between an instant where dx/dt=0 and an instant where dx/dt=cst ? Surely at some time there is a force involved. Now, maybe it's usually neglected because it is negligible for all practical purpose, but if we are to integrate µN ...
So if there is no "thermal expansion acceleration" how do you go from a state of no thermal expansion to a state of ongoing thermal expansion ? Step like ? But this step would still represent some momentum impulse...
Please define the "speed of thermal expansion" that is supposed to be constant, I don't get it.
For instance if one is heating volumetrically a mass of material at linearly growing power at constant rate P(t)=cst t, then we have a heat energy Q that goes as t², and so does temperature T, and if we assume a slow (quasi-static) rate, the material will be at length l(t)=cst + cst*t² hence ldot=velocity=cst*t hence acceleration=cst hence constant inertial force to overcome...
So, one has to solve Fourier's equation (temperature vs time). And the thermal expansion and thermal stresses follow from that. There is no second order derivative with respect to time in Fourier's equation. There is only a first order derivative with respect to time, and other terms containing a second order derivative with respect to space.
There is no "acceleration of temperature term in Fourier's equation". Hence no intrinsic "thermal wave Fourier equation". No "inertia of temperature" term and no "inertia of thermal expansion" term.
You may compute a thermal strain changing with time due to the temperature changing with time: T(t) hence epsilon(t)=alpha*T(t), and a strain rate also changing with time (due to the change with time of the temperature).
The coefficient of thermal expansion is very small, by several orders of magnitude. There is nothing there to produce a large acceleration of thermal deformation term. The "acceleration of thermal deformation" in HD PE should be negligible, and when you multiply it by the mass it should give a negligible force. Such dynamic terms are neglected in thermal problems. Even in the Pioneer anomaly problem, involving extremely small accelerations, what is discussed is the thermal radiation producing recoil forces, but nobody has brought up "thermal expansion forces due to the thermal expansion changing with time", one reason for this being that such thermal expansion cannot accelerate the center of mass for an object free in space, of course. But no issues of "acceleration of thermal expansion" bringing dynamic forces on the antenna either.
Thanks guys !
So I have data for everything except the mode(s), and temp size for the flight cone.
I need to use X numbers of 21, 26, and 77, respectively, for the proto, demo and flight cones to get those numbers. (w/o dielectric that is)
What that means is TBD of course. There may be another variable involved, in or out of favor of a real effect.
I wonder if the following effect has been quantitatively assessed :
if a thermal displacement (again) of a part of significant mass relative to the fixation point can occur, this will change the torque seen by the balance arm around the x axis. (See attached picture for naming conventions). While the flexure bearings make for a very stiff reaction around x and y axis (compared to the natural rotation around z) no stiffness is infinite. Likewise, the Faztek beam could twist a little around the x axis. Since the distance reported in the charts is measured (along the y axis) from a plate below the beam, any increased rotation clockwise would increase this distance.
Contrary to dynamical recoil effects that needs constant acceleration to mimic sustained force, it suffices the deformation is kept at constant position (relative to fixation point) to yield an apparent long lasting force reading. As for the orientation, in this hypothesis one would have to explain a displacement of some mass to the right (relative to fixation point) to get an upward reading (corresponding to a leftward force interpretation). Expansion of frustum's copper walls alone would shift some mass to the left relative to fixation point, so would run contrary to the observed directions. Expansion of a left wall (small end) glued dielectric would go in the right direction, but Paul March reported of a try (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1335583#msg1335583) with the dielectric on the right wall (big end) and the apparent thrust haven't inverted or even reduced...
So, this is on shaky ground on orientations considerations alone, but I'd be curious to know the amount of rotation stiffness around the x axis, maybe that was discussed already ?
Side note : I'm trying to know the exact model of flexure bearings used. From this post (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253522#msg1253522) we know that <<The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg.>> but that doesn't add up with the vertical readings in the charts (from calibration pulses, between 0.033µm and 0.1µm per µN on vertical scale, with still unexplained disparity from chart to chart).
I wonder if the following effect has been quantitatively assessed :
if a thermal displacement (again) of a part of significant mass relative to the fixation point can occur, this will change the torque seen by the balance arm around the x axis. (See attached picture for naming conventions). While the flexure bearings make for a very stiff reaction around x and y axis (compared to the natural rotation around z) no stiffness is infinite. Likewise, the Faztek beam could twist a little around the x axis. Since the distance reported in the charts is measured (along the y axis) from a plate below the beam, any increased rotation clockwise would increase this distance.
Contrary to dynamical recoil effects that needs constant acceleration to mimic sustained force, it suffices the deformation is kept at constant position (relative to fixation point) to yield an apparent long lasting force reading. As for the orientation, in this hypothesis one would have to explain a displacement of some mass to the right (relative to fixation point) to get an upward reading (corresponding to a leftward force interpretation). Expansion of frustum's copper walls alone would shift some mass to the left relative to fixation point, so would run contrary to the observed directions. Expansion of a left wall (small end) glued dielectric would go in the right direction, but Paul March reported of a try (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1335583#msg1335583) with the dielectric on the right wall (big end) and the apparent thrust haven't inverted or even reduced...
So, this is on shaky ground on orientations considerations alone, but I'd be curious to know the amount of rotation stiffness around the x axis, maybe that was discussed already ?
Side note : I'm trying to know the exact model of flexure bearings used. From this post (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253522#msg1253522) we know that <<The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg.>> but that doesn't add up with the vertical readings in the charts (from calibration pulses, between 0.033µm and 0.1µm per µN on vertical scale, with still unexplained disparity from chart to chart).
.... Earlier I proposed this same effect to explain the negative slope in the baseline of the thrust waveform. It appears to have a long time constant so may be from a thermally induced change in CoM.
Thanks guys !
So I have data for everything except the mode(s), and temp size for the flight cone.
I need to use X numbers of 21, 26, and 77, respectively, for the proto, demo and flight cones to get those numbers. (w/o dielectric that is)
What that means is TBD of course. There may be another variable involved, in or out of favor of a real effect.
Realized this morning I'd been missing something after rereading Shawer's flight paper and the Magnetron "lock" time.
Kicking myself for not recognizing a "Q multiplier circuit" (I've used enough of them) The long lock time (time constant) is the tip-off if this is what he's doing and the results are real. The trade off in that case is spectral purity vs the frequency stability of the oscillator since you track the cavity.
Needs only a modest *10 for the proto and demo cases. The flight system needs *100 which is not out of the question at all.
Again, this is pure speculation on my part w/o confirmation from Shawyer, but it puts the mode back in a reasonable range.
I wonder if the following effect has been quantitatively assessed :
if a thermal displacement (again) of a part of significant mass relative to the fixation point can occur, this will change the torque seen by the balance arm around the x axis. (See attached picture for naming conventions). While the flexure bearings make for a very stiff reaction around x and y axis (compared to the natural rotation around z) no stiffness is infinite. Likewise, the Faztek beam could twist a little around the x axis. Since the distance reported in the charts is measured (along the y axis) from a plate below the beam, any increased rotation clockwise would increase this distance.
Contrary to dynamical recoil effects that needs constant acceleration to mimic sustained force, it suffices the deformation is kept at constant position (relative to fixation point) to yield an apparent long lasting force reading. As for the orientation, in this hypothesis one would have to explain a displacement of some mass to the right (relative to fixation point) to get an upward reading (corresponding to a leftward force interpretation). Expansion of frustum's copper walls alone would shift some mass to the left relative to fixation point, so would run contrary to the observed directions. Expansion of a left wall (small end) glued dielectric would go in the right direction, but Paul March reported of a try (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1335583#msg1335583) with the dielectric on the right wall (big end) and the apparent thrust haven't inverted or even reduced...
So, this is on shaky ground on orientations considerations alone, but I'd be curious to know the amount of rotation stiffness around the x axis, maybe that was discussed already ?
Side note : I'm trying to know the exact model of flexure bearings used. From this post (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253522#msg1253522) we know that <<The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg.>> but that doesn't add up with the vertical readings in the charts (from calibration pulses, between 0.033µm and 0.1µm per µN on vertical scale, with still unexplained disparity from chart to chart).
My very first post on this forum was motivated by the rotation produced by the change in location of the center of mass: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1252386#msg1252386
This rotation results in nonlinear coupling of degrees of freedom. I solved the nonlinear coupled differential equations using Mathematica. The coupling is very small because the rotational stiffness for the motion you are considering is much stiffer than the torsional stiffness of Eagleworks torsional pendulum around the vertical axis perpendicular to the ground.
The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg., but that varies with the mass load mounted on the torque pendulum arm and selected balance point of the test article mass and its counterbalance mass on the other end of the pendulum arm relative to the torque pendulum’s center of rotation. Each bearing block is rated for ~25.0 Lb of vertical mass load, so we nominally restrict ourselves to a 25 pound total load limit on the torque pendulum arm to give ourselves a 100% support mass margin.
Based on my interpretation of early discussions with Paul March in Thread 1, I assumed that the compliance for rotation around your x axis was due to the aluminum beams and that the RiverHawk bearings provided an effective clamp condition for rotation around the x axis.I wonder if the following effect has been quantitatively assessed :
if a thermal displacement (again) of a part of significant mass relative to the fixation point can occur, this will change the torque seen by the balance arm around the x axis. (See attached picture for naming conventions). While the flexure bearings make for a very stiff reaction around x and y axis (compared to the natural rotation around z) no stiffness is infinite. Likewise, the Faztek beam could twist a little around the x axis. Since the distance reported in the charts is measured (along the y axis) from a plate below the beam, any increased rotation clockwise would increase this distance.
Contrary to dynamical recoil effects that needs constant acceleration to mimic sustained force, it suffices the deformation is kept at constant position (relative to fixation point) to yield an apparent long lasting force reading. As for the orientation, in this hypothesis one would have to explain a displacement of some mass to the right (relative to fixation point) to get an upward reading (corresponding to a leftward force interpretation). Expansion of frustum's copper walls alone would shift some mass to the left relative to fixation point, so would run contrary to the observed directions. Expansion of a left wall (small end) glued dielectric would go in the right direction, but Paul March reported of a try (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1335583#msg1335583) with the dielectric on the right wall (big end) and the apparent thrust haven't inverted or even reduced...
So, this is on shaky ground on orientations considerations alone, but I'd be curious to know the amount of rotation stiffness around the x axis, maybe that was discussed already ?
Side note : I'm trying to know the exact model of flexure bearings used. From this post (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253522#msg1253522) we know that <<The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg.>> but that doesn't add up with the vertical readings in the charts (from calibration pulses, between 0.033µm and 0.1µm per µN on vertical scale, with still unexplained disparity from chart to chart).
My very first post on this forum was motivated by the rotation produced by the change in location of the center of mass: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1252386#msg1252386
This rotation results in nonlinear coupling of degrees of freedom. I solved the nonlinear coupled differential equations using Mathematica. The coupling is very small because the rotational stiffness for the motion you are considering is much stiffer than the torsional stiffness of Eagleworks torsional pendulum around the vertical axis perpendicular to the ground.
Yes I recall that, but can't find the values you used, don't remember if you published or just PM to someone asking. At the moment my concern is not that much on coupling, but on absolute stiffness around the x axis (as seen from torque around x applied 10'' from the z axis). Do you know or have derived the exact flexure bearing model ? Is it a tandem of 2 C-Flex E-10 or B-20 at .0037 Lb-in/degree each as found there http://www.c-flex.com/companyproducts.pdf or a tandem of 2 RiveHawk like 5005-600 (.0035) or 5006-660 (.0037) or 5010-800 (.0036).
From this post :
(http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253522#msg1253522)Quote from: Star-DriveThe Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg., but that varies with the mass load mounted on the torque pendulum arm and selected balance point of the test article mass and its counterbalance mass on the other end of the pendulum arm relative to the torque pendulum’s center of rotation. Each bearing block is rated for ~25.0 Lb of vertical mass load, so we nominally restrict ourselves to a 25 pound total load limit on the torque pendulum arm to give ourselves a 100% support mass margin.
Have we anything more specific ?
For vertical mass load (ie. axial load) E-10 is rated 36.48 Lb, B-20 is 19.6 Lb (page 11 C-Flew spec sheet). From axial load indication could be A-30 or C-20, A-30 is too stiff...
Nearest fit (if 0.007 in-Lb/deg is for each) would then be C-20 : 0.0060 in-Lb/deg and 27.90 Lb axial
For RiverHawk I don't find axial load ratings, neither at here (http://flexpivots.com/wp-content/uploads/2014/07/Riverhawk-FlexuralPivotCatalog.pdf) nor there (http://flexpivots.com/wp-content/uploads/2014/07/Riverhawk-FlexuralPivotEngineeringData.pdf).
Anyhow, even if we have 2 times .007 in-Lb/deg. that's 9.06e-2 Nm/rad (please check as I'm not used to imperial units) and a 29.1µN (calibration pulse) at 10'' from z axis is 7.39e-6 Nm, so we should have 8.16e-5 rad, that is 20.7 µm deviation (at 10'' from z axis, LDS is a bit further so it should be even a bit more).
Yet we see on the charts that the calibration pulses give between 1 to 2.5 µm deviation on the vertical scale. We don't know why this should be varying from chart to chart, and there is one order of magnitude difference with the given stiffness. So maybe the indicated vertical scale is irrelevant... but then it becomes difficult to model the system. Looks like the flexure bearing are stiffer than 0.007 in-Lb/deg. (around z).
Thanks guys !
So I have data for everything except the mode(s), and temp size for the flight cone.
I need to use X numbers of 21, 26, and 77, respectively, for the proto, demo and flight cones to get those numbers. (w/o dielectric that is)
What that means is TBD of course. There may be another variable involved, in or out of favor of a real effect.
Realized this morning I'd been missing something after rereading Shawer's flight paper and the Magnetron "lock" time.
Kicking myself for not recognizing a "Q multiplier circuit" (I've used enough of them) The long lock time (time constant) is the tip-off if this is what he's doing and the results are real. The trade off in that case is spectral purity vs the frequency stability of the oscillator since you track the cavity.
Needs only a modest *10 for the proto and demo cases. The flight system needs *100 which is not out of the question at all.
Again, this is pure speculation on my part w/o confirmation from Shawyer, but it puts the mode back in a reasonable range.
Notsosureofit:
Could you describe to me how one goes about building a "Q-multiplier Circuit" for a 1.90 GHz RF amplifier circuit? I've used the old Heathkit QF-1 Q-Multiplier for my old shortwave radio receiver back in high school, see: http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_O-RX/QF-1/QF-1.pdf , but I've never thought to use one to enhance the Q-Factor of a microwave frustum cavity before...
Best, Paul M.
Dr. Rodal & Crew:
The Eagleworks team has already build a 6061 aluminum frustum cavity with 1/4" thick walls and O-ring end caps meant to hold a 1 Bar pressure differential with internal nickel/copper/silver/gold plating system on all interior surfaces with plating thickness of 10-to-15 microns for the first three layers and 0.5 microns for exposed to the RF gold layer. Sadly the gold layer was just as thick as the rest of the plated layers and textured as well, so as far as the applied ~2.0 GHz RF was concerned it was only interacting with the rough gold layer. This had the effect of cutting the resonant Q-factor for this aluminum frustum by almost a factor of three over our copper frustum for the resonances of interest.
At the same time we also tried using a smaller volume, higher-K (e-r=~40) ceramic dielectric resonator discs in the Al cavity mounted at its small OD end, while driving it at its TE011 mode if memory serves. Bottom line was that this configuration was a total bust in regards to thrust production in our torque pendulum system running at this resonant mode. This aluminum frustum design also turned out to be ~4X times the mass of the thin walled copper cavity even while using lower density aluminum for its construction. This exercise was a tribute to the fact that one should never ASSUME that you know what you are doing until proven otherwise! And oh yes, and only try one variation in the design at a time or one will get lost, fast!
Best, Paul M.
...
These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
DIYFAN:I couldn't find magnetic permeability values for mu metal close to the GHz range, except the frequent warning (also included in the Wikipedia article) <<The high permeability makes mu-metal useful for shielding against static or low-frequency magnetic fields>> (bold added for emphasis).
Once the test series we are working on is finished, I will suggest to Dr. White that we try the use of the more readily available NiFeCo mu-metal from McMaster-Carr (See: http://www.mcmaster.com/#mu-metal-foil/=w4hfa3 ) for such a test. However I think we will have to copper plate the side of the mu-metal facing the interior of the cavity with about 10 microns of copper or silver to keep this large OD end-cap from greatly reducing the Q-Factor of the copper frustum. Mu-metal resistivity is much higher than copper...
Best, Paul M.
Dr. March,
I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :
- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.
While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) :Quote from: Star-Drive...
These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
Thanks
@MulletronAre you modeling the geometrical shape now with a 3-D (three-dimensional) MEEP mesh or is your present MEEP model a flat plane with a rectangular boundary (2-D two-dimensional model) ?
I made some cylindrical cavity runs.....
Thanks guys !
So I have data for everything except the mode(s), and temp size for the flight cone.
I need to use X numbers of 21, 26, and 77, respectively, for the proto, demo and flight cones to get those numbers. (w/o dielectric that is)
What that means is TBD of course. There may be another variable involved, in or out of favor of a real effect.
Realized this morning I'd been missing something after rereading Shawer's flight paper and the Magnetron "lock" time.
Kicking myself for not recognizing a "Q multiplier circuit" (I've used enough of them) The long lock time (time constant) is the tip-off if this is what he's doing and the results are real. The trade off in that case is spectral purity vs the frequency stability of the oscillator since you track the cavity.
Needs only a modest *10 for the proto and demo cases. The flight system needs *100 which is not out of the question at all.
Again, this is pure speculation on my part w/o confirmation from Shawyer, but it puts the mode back in a reasonable range.
Notsosureofit:
Could you describe to me how one goes about building a "Q-multiplier Circuit" for a 1.90 GHz RF amplifier circuit? I've used the old Heathkit QF-1 Q-Multiplier for my old shortwave radio receiver back in high school, see: http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_O-RX/QF-1/QF-1.pdf , but I've never thought to use one to enhance the Q-Factor of a microwave frustum cavity before...
Best, Paul M.
"Q-multiplier" is the Heath term for adding feedback, short of oscillation, to an IF amplifier to narrow the bandwidth
and enhance its "Q" as a filter. (had one on an HRO receiver in the 50's. HRO long gone but the Q-Multiplier is still in the pile somewhere)
In the case of greater feed back you get an oscillator. (had a 220MHz re-entrant cavity oscillator at that time)
The right feedback loop will improve the phase coherence of the oscillation and the "circuit Q". You pay for this with an increased time constant and are limited by the (thermal ?) drift rate of the cavity. The "flight" cavity might be heavily built for that reason ?
Hopefully there is a radar guy (like Shawyer) on tap that could give a better explanation. (I'm pulling this out of memories of my misspent youth...)
I was trying to remember something about radar systems (Russian ?) that had a dielectric resonator suspended in a microwave cavity.............
DIYFAN:I couldn't find magnetic permeability values for mu metal close to the GHz range, except the frequent warning (also included in the Wikipedia article) <<The high permeability makes mu-metal useful for shielding against static or low-frequency magnetic fields>> (bold added for emphasis).
Once the test series we are working on is finished, I will suggest to Dr. White that we try the use of the more readily available NiFeCo mu-metal from McMaster-Carr (See: http://www.mcmaster.com/#mu-metal-foil/=w4hfa3 ) for such a test. However I think we will have to copper plate the side of the mu-metal facing the interior of the cavity with about 10 microns of copper or silver to keep this large OD end-cap from greatly reducing the Q-Factor of the copper frustum. Mu-metal resistivity is much higher than copper...
Best, Paul M.
I wonder what is the relative magnetic permeability of mu metal in the GHz range, and how effective it will be for the purposes described by Aquino.
Please fill-in the following data (question marks ? below) for the cylindrical cavity with a dielectric section having the same diameter as the cavity's ID and located at one end of the cavity:
Maybe Dr. Rodal will tell me what the resonant frequency should be for the cylindrical cavity with dielectric that I posted data for earlier today?
Realized this morning I'd been missing something after rereading Shawer's flight paper and the Magnetron "lock" time.
Kicking myself for not recognizing a "Q multiplier circuit" (I've used enough of them) The long lock time (time constant) is the tip-off if this is what he's doing and the results are real. The trade off in that case is spectral purity vs the frequency stability of the oscillator since you track the cavity.
Needs only a modest *10 for the proto and demo cases. The flight system needs *100 which is not out of the question at all.
Again, this is pure speculation on my part w/o confirmation from Shawyer, but it puts the mode back in a reasonable range.
Notsosureofit:
Could you describe to me how one goes about building a "Q-multiplier Circuit" for a 1.90 GHz RF amplifier circuit? I've used the old Heathkit QF-1 Q-Multiplier for my old shortwave radio receiver back in high school, see: http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_O-RX/QF-1/QF-1.pdf , but I've never thought to use one to enhance the Q-Factor of a microwave frustum cavity before...
Best, Paul M.
"Q-multiplier" is the Heath term for adding feedback, short of oscillation, to an IF amplifier to narrow the bandwidth
and enhance its "Q" as a filter. In the case of greater feed back you get an oscillator. The right feedback loop will improve the phase coherence of the oscillation and the "circuit Q". You pay for this with an increased time constant and are limited by the (thermal ?) drift rate of the cavity. The "flight" cavity might be heavily built for that reason ?
The "Q multiplier" effect comes from the calculation of the loaded resonator Q, as f/2 times the loop gain phase slope.
"Loaded-Q represents the width of the resonance curve, or phase slope, including the effects of external components. In this case the Q is determined mostly by the external
components."
In typical references that I found, ie. low noise frequency sources, the loaded Q is between 20% to 50% of the unloaded Q.
So for the "Shawyer" type application, to get a maximized loaded Q in a cavity oscillator, one should maximize the loop gain phase slope. (use the highest gain-bandwidth amp you can find ?)
....Very interesting that this is the only example readily available in a quick search. The example comes from Lima, Peru. One cannot help but wonder whether the worked out analysis in the example is flawless and whether it can work in practice to increase the loaded Q over that of the unloaded Q of the EM Drive.
The oscillator model is the same as the tuned amp model w/ the cavity used as a filter in the feedback loop. In a quick search, I was only able to find one worked out example of using feedback to increase the loaded Q of an oscillator over that of the unloaded Q.
www.zen22142.zen.co.uk/Design/vcqmswo.pdf
Please fill-in the following data (question marks ? below) for the cylindrical cavity with a dielectric section having the same diameter as the cavity's ID and located at one end of the cavity:
Maybe Dr. Rodal will tell me what the resonant frequency should be for the cylindrical cavity with dielectric that I posted data for earlier today?
GEOMETRY
Inner Diameter of cylindrical cavity = ? meters (cavity has a constant, same diameter throughout)
Total Inner Length of cavity = ? meters (Length including dielectric length)
Length of dielectric section = ? meters
CONSTITUTIVE PROPERTIES
Relative electric permittivity of dielectric = ? (dimensionless) (for HD PE it is reported as 2.3)
Relative magnetic permeability of dielectric = ? (dimensionless) (1 ?)
Relative electric permittivity of empty section = ? (dimensionless) (air or vacuum ?)
Relative magnetic permeability of empty section = ? (dimensionless) (air or vacuum ?)
FREQUENCY of interest
There are an infinite number of resonant frequencies for a resonant cylindrical cavity.
What resonant frequency are you referring to? ? (The lowest natural frequency? )
Please fill-in the following data (question marks ? below) for the cylindrical cavity with a dielectric section having the same diameter as the cavity's ID and located at one end of the cavity:
Maybe Dr. Rodal will tell me what the resonant frequency should be for the cylindrical cavity with dielectric that I posted data for earlier today?
GEOMETRY
Inner Diameter of cylindrical cavity = ? meters (cavity has a constant, same diameter throughout)
Total Inner Length of cavity = ? meters (Length including dielectric length)
Length of dielectric section = ? meters
CONSTITUTIVE PROPERTIES
Relative electric permittivity of dielectric = ? (dimensionless) (for HD PE it is reported as 2.3)
Relative magnetic permeability of dielectric = ? (dimensionless) (1 ?)
Relative electric permittivity of empty section = ? (dimensionless) (air or vacuum ?)
Relative magnetic permeability of empty section = ? (dimensionless) (air or vacuum ?)
FREQUENCY of interest
There are an infinite number of resonant frequencies for a resonant cylindrical cavity.
What resonant frequency are you referring to? ? (The lowest natural frequency? )
I just printed these numbers out from my program so this is what I used when generating the posted data.
Inner diameter of cylindrical cavity, 0.08278945,m
total inner length of cavity, 0.1224489,m
Length of dielectric section 0.027282494103102, m
Relative electric permittivity of dielectric =1.76
Relative magnetic permeability of dielectric = 1
Relative electric permittivity of empty section = vacuum (a meep program option)
Relative magnetic permeability of empty section = vacuum
I know that the dielectric constant of hdpe is 2.3. I will make some runs later using that value but for now I am using 1.76.
The resonances I'm looking for are those at the peaks of the force/power curves above, near 1.8 Ghz, 1.9 GHz and 2.4 GHz using an electric source, and about 2.3 GHz with the magnetic source.
It could be that there are no resonances in those frequency ranges but everything we know right now says that there will be.
And thanks.
... snip ...
Maybe Dr. Rodal will tell me what the resonant frequency should be for the cylindrical cavity with dielectric that I posted data for earlier today?
... snip ...
GEOMETRICAL INPUT for cylindrical cavity:
bigDiameter = 8.278945 centimeter;
smallDiameter = bigDiameter;
length = 12.24489 centimeter;
dielectricThickness = 2.7282494103102 centimeter;
You can verify this case directly from equation in Wikipedia http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity
First four mode shapes and frequencies for Relative electric permittivity of dielectric =1 (No dielectric)
{{"TE", 1, 1, 0}, 2.12223*10^9},
{{"TE", 1, 1, 1}, 2.44998*10^9}, {{"TM", 0, 1, 0}, 2.77191*10^9}, {{"TM", 0, 1, 1}, 3.03019*10^9}
First three mode shapes and frequencies for Relative electric permittivity of dielectric =1.76; dielectricThickness = 2.7282494103102 centimeter
{{"TE", 1, 1, 1}, 2.31958*10^9}, {{"TE", 1, 1, 2}, 3.03479*10^9}, {{"TM", 0, 1, 2}, 3.47425*10^9}
First three mode shapes and frequencies for Relative electric permittivity of dielectric =2.3; dielectricThickness = 2.7282494103102 centimeter
{{"TE", 1, 1, 1}, 2.26774*10^9}, {{"TE", 1, 1, 2}, 2.93557*10^9}, {{"TM", 0, 1, 2}, 3.37114*10^9}
Perhaps you are getting much lower frequencies because you are using Maxwell's equations in 2-D ?, and you are modeling the cavity as a flat plane bounded by a rectangle instead of 3-D cylindrical cavity under 3-D Maxwell's equations
Dr. March,
I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :
- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.
While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) :Quote from: Star-Drive...
These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
Thanks
Frobnicat:
To answer your question:
" - That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference?"
The two torsion bearings used in or torque pendulum are supposed to have a stiffness of 0.007 in-Lb/deg, +/-10% and is made by the Riverhawk Co. in New York USA. As to their model number find the data sheet for same attached.
"- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
"While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilization or tuning purpose)?"
The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should.
Best, Paul M.
"- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
"While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilization or tuning purpose)?"
The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should.
Best, Paul M.
"- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
"While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilization or tuning purpose)?"
The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should.
Best, Paul M.
The torque pendulum arm had a slight tilt so that alignment was easier. The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror by measuring the intensity of the reflected light. If the change in the center of mass reduces the pendulum arm tilt, the light intensity may increase. This would explain the negative slope of the baseline waveform (apparent movement closer) after the RF is switched off. It would be interesting to see what the thrust waveform looks like when the cavity is turned around.
....
In my opinion such a low tempo low priority side project that could probably be fully funded from the couch change from break room lounge chairs should not be micromanaged like it's a multi-billion dollar resource intensive space probe project and put under deadline pressure like that.
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
...
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Hello Mulletron,
Hope you'll be able to conduct another test, and I guess there are many other people like me who encourage you to continue.
How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?
--
Mathieu
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
...
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Hello Mulletron,
Hope you'll be able to conduct another test, and I guess there are many other people like me who encourage you to continue.
How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?
--
Mathieu
Going to do a Cavendish experiment:
http://www.intalek.com/Index/Projects/Research/CavendishExperiment.htm
https://www.fourmilab.ch/gravitation/foobar/ (link is down right now, hope it comes back)
https://www.youtube.com/watch?v=dyLYbvZIYoU
Don't need expensive gear. You can do amazing things with some fishing line and ingenuity.
Does anyone clearly understand the reaction force R vs opposite thrust T in Shawyer's newest document "A Note on the Principles of EmDrive force measurement" (http://www.emdrive.com/EmDriveForceMeasurement.pdf) that I attach to this message? Especially, the problem of the "restrained thruster" of fig. 3 where no movement could be detected at all?
Shawyer seems to imply that the EmDrive needs to experience an acceleration (even the slightest one) to create a force that would me measurable. A fully restrained cavity would not move at all. It reminds me of the the Mach effect thruster, where according to Woodward the material needs to undergo a proper acceleration while being energized, otherwise the transient mass fluctuation does not occur.
Evidently, Eagleworks' RF resonant cavity test article is fixed to the rest of the apparatus, but Shawyer explains any small thermal effect makes the walls move hence the center of gravity of the cavity also move a bit, and this would be enough for any small force to appear.
Does anyone clearly understand the reaction force R vs opposite thrust T in Shawyer's newest document "A Note on the Principles of EmDrive force measurement" (http://www.emdrive.com/EmDriveForceMeasurement.pdf) that I attach to this message? Especially, the problem of the "restrained thruster" of fig. 3 where no movement could be detected at all?
Shawyer seems to imply that the EmDrive needs to experience an acceleration (even the slightest one) to create a force that would me measurable. A fully restrained cavity would not move at all. It reminds me of the the Mach effect thruster, where according to Woodward the material needs to undergo a proper acceleration while being energized, otherwise the transient mass fluctuation does not occur.
Evidently, Eagleworks' RF resonant cavity test article is fixed to the rest of the apparatus, but Shawyer explains any small thermal effect makes the walls move hence the center of gravity of the cavity also move a bit, and this would be enough for any small force to appear.
Thanks you two. I was under the bad impression I was silly for not understanding Shawyer's explanations.There is an easy way to test this.
If one looks closely at the contour plots of the TM modes in http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340906#msg1340906, one will notice that Egan's contour plots have the maximum of the magnetic field occurring at the cone surface while my contour plots have the maximum of the magnetic field occurring at a distance from the cone's surface. I have examined the source of this discrepancy. My conclusion is that Egan's plots are incorrect regarding this feature, and they are inconsistent with the equations on Egan's post. If anybody is interested to know why, I can post the mathematical proof and discussion for this conclusion.OK. I will interpret the "likes" I got for the previous post, as meaning that they would like me to explain why I have arrived at the conclusion that Egan's contour plots that show the maximum of the magnetic field occurring at the cone surface are incorrect, and why my contour plots have the maximum of the magnetic field occurring at a distance from the cone's surface.
Thanks you two. I was under the bad impression I was silly for not understanding Shawyer's explanations.There is an easy way to test this.
Paul March said that they need to maximize the thrust for the experiment to be verified at NASA Glenn.
Paul March measures the displacement vs. time with an optical method as previously discussed in detail by zen-in "Philtec D63 fiber-optic displacement sensor measures distance from its target mirror by measuring the intensity of the reflected light.".
If Shawyer is correct that the less restraint the better, then Paul March could lessen the current restraint in his experiments by replacing the RiverHawk bearing with another one (if available) having less stiffness. If Shawyer is correct, the decrease in restraint should produce an increase in the measured response.
....
The only thing that I see that can account for the apparent lacking torque is the equilibrating torque induced by the inclination of the plane of rotation of the arm toward the CoM of the rotating assembly, that is equivalent to a hanging pendulum. The way it is used, the balance is more than 90% a hanging pendulum and less than 10% a torsion pendulum driven by flexure stiffness.
If this analysis holds, small changes in stiffness of flexure bearings would make for a minor impact on results. Changes in inclination would be the major way to tune the (linearised hanging pendulum equivalent) stiffness.
Do you mean that this might actually be right? I've ignored the fields that look like this because I thought they were supposed to be symmetric.
Dr. March,
I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :
- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.
While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) :Quote from: Star-Drive...
These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
Thanks
Frobnicat:
To answer your question:
" - That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference?"
The two torsion bearings used in or torque pendulum are supposed to have a stiffness of 0.007 in-Lb/deg, +/-10% and is made by the Riverhawk Co. in New York USA. As to their model number find the data sheet for same attached.
"- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
"While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilization or tuning purpose)?"
The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should.
Best, Paul M.
Thank you very much for those precious informations. The tilt angle magnitude can probably be inferred from the deviation against the calibration pulses, if we can model the gravitational pendulum component on top of the flexure bearing restoring torque component.
For that we need to know :
Mass of :
frustum, without dielectric : 1.606 kg
microwave power amplifier : below 8kg ?
faztek horizontal beam : 2.18 Lb (from 1.09Lb/Ft) ?
Ideally, Total mass with a rough estimate of position of each part...
Distances along the arm from vertical axis of rotation to the centre of :
Long end of arm (frustum side) : 15.5''
Short end of arm (amplifier side) : 8.5''
Frustum : 15.5 - 4 = 11.5'' ?
Electrostatic Fins Calibration System : 15.5-4 = 11.5'' ?
Linear Displacement Sensor : 15.5-1 = 14.5'' ?
microwave power amplifier : between 4.25'' and 8.5'' ?
Stiffness of flexure bearings : .014 in-Lb/deg total (2 times .007 each)
In short : what is the total mass of the whole rotating assembly, where is the centre of mass of the whole rotating assembly relative to axis of rotation, and what is the moment of inertia around the (almost) vertical axis of rotation (for the later, to assess the dynamics and not just the equilibrium).
green : explicitly provided value
orange : inferred from pictures or derived by me from faztek sellers, to be confirmed
red : not found, do we have better than bounds for those ?
Thank you Dr. Rodal - So here is the complete set for some magnetic source run. I didn't record any details except I can see that the antenna in in the location of the magnetic antenna I use. Is it possible that all of the images are correct? If so that would increase my confidence in the meep output.Yes, they can all be correct. But we need your help in identifying the images you posted. The electric and magnetic fields are vectors in 3-D space, with orthogonal base vector components.
Grenade!I attach the actual paper (available at arXiv) by James Quach on the Gravitational Casimir effect for those interested to read it for personal research purposes. All others should access it through the American Physical Society at http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.081104
http://phys.org/news/2015-03-theorist-gravitational-casimir.html
if experiments show the Casimir pressure to be an order of magnitude larger than that predicted from the photonic contribution alone, this would be the first experimental evidence for the validity of the H-C theory and the existence of gravitons. This would open a new field in the way of graviton detection.
Grenade!
http://phys.org/news/2015-03-theorist-gravitational-casimir.html
Thank you Dr. Rodal - So here is the complete set for some magnetic source run. I didn't record any details except I can see that the antenna in in the location of the magnetic antenna I use. Is it possible that all of the images are correct? If so that would increase my confidence in the meep output.Yes, they can all be correct. But we need your help in identifying the images you posted. The electric and magnetic fields are vectors in 3-D space, with orthogonal base vector components.
For example, what does this represent? Is this a contour plot of the electric field component oriented along the axial direction (the vector component oriented along the "y" axis)? The reason why I think it is the axial component is because the axial component should be symmetric about the "y" axis (which it is)
Notice how although you impose flat faces, the electromagnetic field inside the cavity wants to be spherical (thus the 2 curved boundaries between the 3 contour regions). Left to its own, Nature will do what it wants to do: to propagate as spherical waves. The radii of the 2 curved boundaries look correct. The radii of curvature seem to have the same center as the focal point of intersection of the sides of the truncated cone (the vertex or apex of the cone).
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=811566;image)
I'm currently trying to finish up the cross section drawing on the flight demonstrator, but i kinda fail to understand how it fits together....
Looking closely (top down wise) at the lower rim it seems to me there is :
-small shiny rim (could be the edge of the alu cone?)
-brownish plate (copper plate?)
-small shiny rim
-thick plate (most probably holding the screw thread)
I'm puzzled about the second small, shiny rim...
Why would you need an additional small slab of alu under the (supposedly) copper plating?
Any one has an idea?
FYII see the brown reflection of the wood-like table on the left side of the plate, and the shiny rim.
https://www.dropbox.com/s/rtp9gx844yxu6ef/IMAG0372.jpg?dl=0
....
The only thing that I see that can account for the apparent lacking torque is the equilibrating torque induced by the inclination of the plane of rotation of the arm toward the CoM of the rotating assembly, that is equivalent to a hanging pendulum. The way it is used, the balance is more than 90% a hanging pendulum and less than 10% a torsion pendulum driven by flexure stiffness.
If this analysis holds, small changes in stiffness of flexure bearings would make for a minor impact on results. Changes in inclination would be the major way to tune the (linearised hanging pendulum equivalent) stiffness.
A hanging pendulum hangs from a rigid support located above the weight. Its period depends only on the length of the pendulum's arm (and g , the acceleration of gravity, which is practically constant on Earth). The flexural stiffness of the pendulum's arm is negligible.
But here nothing is hanging from the stainless steel chamber "rigid ceiling" supported by arms with negligible flexural stiffness.
What I see is the EM Drive weight supported by a frame of Faztek aluminum beams, Faztek beams that are supported from below, not from the stainless steel chamber ceiling.
What rigid support (located above the EM Drive) is the EM Drive hanging from ? (Where is the "hanging pendulum" rigid support located ?)
What constitutes the arm of the "hanging pendulum"? Why does it have negligible flexural stiffness? (The flexural stiffness of the aluminum Faztek beams is far from being negligible)
Do you really mean a hanging pendulum (whose period depends only on the length of the arm)?
Or do you mean a flexural pendulum (whose period depends on the stiffness of the arm)?
And if you agree that the flexural stiffness of the arms are not negligible, why take into account only the portion above the weight? What about the flexural stiffness below the weight?
Aren't the Faztek beams supported from below?
What I see is your "z" axis going up to a Faztek frame or "bridge" and the "bridge" being supported by two vertical Faztek beams, and those vertical Faztek beams are supported from below, not from above.
Is that then really an inverted flexural/torsional pendulum since it is made by Faztek aluminum beams supported from below?
... pics ...
....Thank you for taking the time to draw these excellent pictures. A picture is worth 1000 words.
It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....
The "Copper" is just the reflection of the floor from the side of the flange. The 2 bright lines are reflections from the edge bevels. If they used the Copper CF (or wire) seals they are located inside of the bolt line.
Do you have a reference giving frequency, Q, power and thrust measurements for the Flight Thruster?
This is the only reference I have for data for the Flight Thruster: http://emdrive.com/flightprogramme.html, I can't find a Q reported.
Several of them for the "Flight Thruster Programme":
Shawyer's CEAS 2009 paper (http://www.emdrive.com/CEAS2009paper.doc) stated, page 9:QuoteThe Flight thruster programme covers the design and development of a 300 Watt C Band flight thruster. This has a specified thrust of 85 mN, and a mass of 2.92Kg. Overall dimensions are 265mm diameter at the baseplate and a height of 164mm.
Then in the 2010 Toulouse TECHNO DIS paper (http://www.emdrive.com/Toulouse2010paper01.doc), page 8:QuoteDevelopment testing of the unit, up to a power of 600 W, is under way, and to date, has given a mean specific thrust of 330 mN/kW.
[…]
This is needed to ensure the input frequency matches the resonant frequency of the high Q (60,000) cavity, over the full input power range and the qualification temperature specification.
And in the IAC 2013 paper (http://www.emdrive.com/IAC13paper17254.v2.pdf), page 4:QuoteThe Dynamic performance of the non superconducting Flight Test model, manufactured and tested by SPR Ltd, and described in REF 3 [N.B.: 2010 Toulouse TECHNO DIS paper] was modeled with a cavity Qu = 50,000 and Fres=3.85 GHz.
Finally the mean specific thrust of 326mN/kW over 19 test runs of up to 90 secs duration from 150 W to 450 W was found on the web page http://emdrive.com/flightprogramme.html
As well as the diagram which shows the maximum thrust achieved @ 450 W:
(http://emdrive.com/images/results2.jpg)
If the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:
224mm base diameter
145mm top diameter
164mm height (given by Shawyer).
Here's the chart if anyone is interested, cluttered though it has admittedly become.
Thanks! That brings that X number down to ~55. Still a very high mode, but 3.85GHz !
McCulloch's equation gives 148 milliNewtons for Shawyer's demo, comparing pretty well with Shawyer's reported measurements of 80 to 214 millinNewtons, see:
http://physicsfromtheedge.blogspot.com/2015/02/mihsc-vs-emdrive-data-3d.html
I understand that you need to use X=26 in your equation for Shawyer's Demo, also a high mode.
On the other's hand McCulloch's equation is off by a factor >10 for NASA Eagleworks test results.
That is an interesting fit.
Of course I havn't seen Mike's derivation in 3D. I only follow the Equivalence argument the best I can w/o fudge factors and see what comes out. At the moment I think these are maximums if you have all the parameters and I like the NASA results because they seem to have eliminated more sources of error. Still, it may all be fiction which is what we want to find out.
@ RODAL
Still have question about the Shawyer "Demo" cavity w/ 174mN. What are the current estimates of the cone dimensions, frequency (3.85GHz?), and Q (6000 est?). When I put in TM02 and 450W, I get 174.8microN, rather than the 174milliN reported. I would like to recheck those numbers.
Even w/ Q=45000, I need to get X up around (65 Very high mode) to get those numbers. Is that possible w/ 3.85GHz ??
Thanks
....Thank you for taking the time to draw these excellent pictures. A picture is worth 1000 words.
It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....
What compliance is responsible for the tilt in the Z axis of rotation around the Y axis) ? You state that the tilt is not due to the Faztek beam compliance (although if the Faztek beam would be compliant enough it certainly would tilt).
If it is not due to the Faztek beam compliance, then my understanding is that you are saying that it is due to the compliance of the Riverhawk bearing. I had interpreted what was written about the Faztek bearings as providing a clamp condition (no tilt).
Do you have quantitative information from the Riverhawk bearing manufacturer as to what is the magnitude of the torsional stiffness for a rotation around the Y axis provided by two Riverhawks that would allow such a tilt around the Y axis?
NOTE: if such a tilt occurs, due to compliance of the Riverhawk bearings around the Y axis, it would be analogous to a flexural pendulum, with flexural stiffness given by the magnitude of the Riverhawk torsional stiffness for a rotation around the Y axis.
......
While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331580#msg1331580) :Quote from: Star-Drive...
These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.
...
The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should.
Best, Paul M.
....Thank you for taking the time to draw these excellent pictures. A picture is worth 1000 words.
It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....
What compliance is responsible for the tilt in the Z axis of rotation around the Y axis) ? You state that the tilt is not due to the Faztek beam compliance (although if the Faztek beam would be compliant enough it certainly would tilt).
If it is not due to the Faztek beam compliance, then my understanding is that you are saying that it is due to the compliance of the Riverhawk bearing. I had interpreted what was written about the Faztek bearings as providing a clamp condition (no tilt).
Do you have quantitative information from the Riverhawk bearing manufacturer as to what is the magnitude of the torsional stiffness for a rotation around the Y axis provided by two Riverhawks that would allow such a tilt around the Y axis?
NOTE: if such a tilt occurs, due to compliance of the Riverhawk bearings around the Y axis, it would be analogous to a flexural pendulum, with flexural stiffness given by the magnitude of the Riverhawk torsional stiffness for a rotation around the Y axis.
And a thousand English words is a lot of sweat for me :)
To answer your questions : while I consider looking for compliance aspects, both for faztek structural elements and for the bearings, there is no compliance implied by my latest post, the tilt would be voluntarily introduced for the whole experiment platform, including the bearing supporting fixed parts (the supporting axis is tilted, not just the arm or arm's rotation axis). That's how I read the answer of Star-Drive :....
Trying to post emdrive5.xls
The flight thruster is shown as what appears to be an oscillator configuration, so it is still possible that the loaded Q is higher than the unloaded Q. But that is speculation. I do worry about his concept of "no static thrust" as well.Shawyer's EM Drive was never tested in a vacuum as far as I know. One wonders whether thermal effects (convection current generation) are very significant for Shawyer's and the Chinese tests due to the very large power input, in other words: is a big portion of Shawyer's (and the Chinese) thrust measurement due to thermal effects ?
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)
...I understand that your expression is based on the exact solution for a cylindrical cavity. Is there a reason why a cylindrical cavity thrust should depend on the cross-sectional quantum numbers "m" and "n" but not depend on the axial quantum number "p"?
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)
...I understand that your expression is based on the exact solution for a cylindrical cavity. Is there a reason why a cylindrical cavity thrust should depend on the cross-sectional quantum numbers "m" and "n" but not depend on the axial quantum number "p"?
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)
The exact solution for the cylindrical cavity has a frequency dependent on "p". Why isn't thrust dependent on "p" ?
...The problem is that the exact solution is not closed-form: it requires the solution of two eigenvalue problems which have no closed-form solution.
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)
So, then in order to produce 'thrust,' this device MUST be a truncated cone - preferably with a rounded base?
Also a wild and stupid thought about Sawyer's commentary: maybe he envisions this device as some sort of 'turbo-charger?' That is something that adds to an already existing velocity, but won't function well, if at all when 'at rest.' Say you have a spacecraft in motion at speed X. Flip this drive on, and the speed becomes X+1.
...maybe he envisions this device as some sort of 'turbo-charger?' That is something that adds to an already existing velocity, but won't function well, if at all when 'at rest.' ...A turbocharger, is a device that increases an engine's efficiency and power by forcing extra air into the combustion chamber.
...
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)
...I think I might be able to obtain a closed-form expression for the frequency of a cylindrical cavity with a dielectric at one end. (Or really a cylindrical cavity having two dielectrics in contact with each other: one dielectric at one end and another dielectric with different permitivity and permeability at the other end).
The device must have an asymmetric dispersion relation in some axis.
.....
@ Rodal :
See attached picture to share my mental image. Tilt over-exaggerated for illustration.
Grey : solid rotating assembly (no deformation implied)
Orange/brown : fixed assembly (no deformation implied)
Blue : the ground slab of the vacuum chamber (no deformation implied)
For now, assume a perfect axis of rotation around Z : only one degree of freedom of Grey relative to Orange, the "official" rotation around Z, no compliance implied, Grey kept in the XY plane, plane has same tilt as Orange (XY parallel to Orange platform).
@Star-Drive
Can you confirm this is a correct way to understand that there is a tilt in the axis of rotation ?
@ Rodal :
See attached picture to share my mental image. Tilt over-exaggerated for illustration.
Grey : solid rotating assembly (no deformation implied)
Orange/brown : fixed assembly (no deformation implied)
Blue : the ground slab of the vacuum chamber (no deformation implied)
For now, assume a perfect axis of rotation around Z : only one degree of freedom of Grey relative to Orange, the "official" rotation around Z, no compliance implied, Grey kept in the XY plane, plane has same tilt as Orange (XY parallel to Orange platform).
@Star-Drive
Can you confirm this is a correct way to understand that there is a tilt in the axis of rotation ?
What is the "engine" that the EM Drive is turbocharging?
The bizarre nature of something needing to be free to accelerate for it to produce a force doesn't apply to the turbocharger or to the engine: the engine that is being turbocharged does not need to be accelerating or even be in rigid body motion. Its center of mass can be completely stationary, and the turbocharged engine can then be used for electric power generation, for example, instead of for transporting people as in an automobile.
...
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)...I think I might be able to obtain a closed-form expression for the frequency of a cylindrical cavity with a dielectric at one end. (Or really a cylindrical cavity having two dielectrics in contact with each other: one dielectric at one end and another dielectric with different permitivity and permeability at the other end).
The device must have an asymmetric dispersion relation in some axis.
.....
Would that be of any use to you to improve your equation?
Yes, it is amenable to a closed-form solution since it involves a quartic: 4th order polynomial. OK, exact, closed-form solution for a cylindrical cavity containing two coupled dielectrics coming your way soon, courtesy of Rodal-exact-solutions. I have the solution now for the 4 roots in general. Just have to figure out which root is the real root for which cases....
(and yes the simple dispersion relation drops dependence on "p". Maybe we can get that in there w/ your exact solution ??)...I think I might be able to obtain a closed-form expression for the frequency of a cylindrical cavity with a dielectric at one end. (Or really a cylindrical cavity having two dielectrics in contact with each other: one dielectric at one end and another dielectric with different permitivity and permeability at the other end).
The device must have an asymmetric dispersion relation in some axis.
.....
Would that be of any use to you to improve your equation?
Absolutely ! That should be a very interesting case as it is 2 coupled cavities. Most of these kind of problems use iterative solutions but I think that case may have some unique analytic solutions !
@ Rodal :
See attached picture to share my mental image. Tilt over-exaggerated for illustration.
Grey : solid rotating assembly (no deformation implied)
Orange/brown : fixed assembly (no deformation implied)
Blue : the ground slab of the vacuum chamber (no deformation implied)
For now, assume a perfect axis of rotation around Z : only one degree of freedom of Grey relative to Orange, the "official" rotation around Z, no compliance implied, Grey kept in the XY plane, plane has same tilt as Orange (XY parallel to Orange platform).
@Star-Drive
Can you confirm this is a correct way to understand that there is a tilt in the axis of rotation ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=811757;image)
One aspect of this tilt in the axis of rotation that hasn't been discussed is the requirement for imbalance. The difference in moments on either side of the beam only has to be very slight for it to always come to rest at the same location +/- a micron or two.
A small CW tilt along the X axis of the balance arm would explain the apparent drift in the baseline seen in some of the thrust waveforms. When the cavity has the orientation shown below its CM shifts to the left. This would reduce the tilt, resulting in an increase in brightness of the reflected light the LDS measures; due to the mirror position being closer to an optimal perpendicular position wrt the light beam. The increase in brightness corresponds to a decrease in distance; hence the negative slope. With the device mounted the other way the shift in CM increases the tilt. This reduces the reflected light and is registered as an increase in distance.
No actual motion of the beam occurs. This apparent motion is an optical artifact. This assumes the Philtec distance sensor is used on the far side. If it is used on the near side a small CCW tilt along the X axis of the beam would produce the same effect; except requiring much less rotation from the change in CM.
......
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
...
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
...
@ RODAL
Can you check this ? (working it down)
root1= Sqrt[(
(-4*b^2*(dD1^2-dD2^2)*((L1/c1)^2-(L2/c2)^2))
/ (dD1^2*dD2^2)
+ ((L1/c1)^2+(L2/c2)^2)*p^2
- 2*Sqrt[
(-4*b^2*((L1/c1)^2-(L2/c2)^2)*((dD1*L1/c1)^2-(dD2*L2/c2)^2)*p^2)
/ (dD1^2*dD2^2)
+ (L1^2*L2^2*p^4)
/ (c1^2*c2^2)]) >>>>>>>>>>>>>>>>>>>>>>>>>>>>> )] ??
/ (L1^2/c1^2-L2^2/c2^2)^2]/2
root2= Sqrt[(
(-4*b^2*(dD1^2-dD2^2)*((L1/c1)^2-(L2/c2)^2))
/ (dD1^2*dD2^2)
+ ((L1/c1)^2+(L2/c2)^2)*p^2
+ 2*Sqrt[
(-4*b^2*((L1/c1)^2 - (L2/c2)^2)*((dD1*L1)/c1)^2-(dD2*L2/c2)^2)*p^2)
/ (dD1^2*dD2^2)
+ (L1^2*L2^2*p^4)
/ (c1^2*c2^2)]) >>>>>>>>>>>>>>>>>>>>>>>>>>>>> )] ??
/ (L1^2/c1^2-L2^2/c2^2)^2]/2
where we define the following dimensionless ratios as follows:
dD1 = diameter/L1;
dD2 = diameter/L2;
and where
L1 = length - L2;
where length is the total internal length of the cylindrical cavity.
The quantity "b" is defined as follows:
b := If[modetype == "TM", xbesselzeros[[i + 1, j]]/Pi, If[modetype == "TE", xprimebesselzeros[[i + 1, j]]/Pi]]
Thanks
Great !
Next need to solve for the expression (f0^2 - f2^2) where (f0 => L1+L2=0 and f2 =>L1+L2=L ??)
Hmmm, let me think about that for a second. What we want to do is isolate the (p*pi/L)^2 term so it will cancel out leaving the Doppler shifts in the accelerated frame. ie. (f0^2 - f2^2)
@ RODAL
I'm struggling w/ the best way to explain it. We want to get the expression (f0^2 - f2^2) such that the frequencies
f0 and f2 are evaluated at the two ends of the cavity at the same wavenumber. They are the frequencies (energies) that would appear at the ends of the cavity if it were accelerated to the point that the dispersion between the ends were to disappear.
Yes, dispersion curve intersections at constant k.
No by df I just mean f1-f2 ie del f
From f^2 evaluations at the ends (ie (f1^2-f2^2) = del f * 2f0 etc.
[Excuse the quick..I'm being otherwise distracted at the moment]
@ RODAL
I'm struggling w/ the best way to explain it. We want to get the expression (f0^2 - f2^2) such that the frequencies
f0 and f2 are evaluated at the two ends of the cavity at the same wavenumber. They are the frequencies (energies) that would appear at the ends of the cavity if it were accelerated to the point that the dispersion between the ends were to disappear.
Yes, dispersion curve intersections at constant k.
No by df I just mean f1-f2 ie del f
From f^2 evaluations at the ends (ie (f1^2-f2^2) = del f * 2f0 etc.
[Excuse the quick..I'm being otherwise distracted at the moment]
This time, instead of purely geometrical terms for the truncated cone with only one medium like
(b^2)*((1/Rs)^2 - (1/Rb)^2)
one gets terms due to the different speed of light in mediums 1 and 2 for example
(b^2)*((L1/c1)^2 -(L2/c2)^2)
=> this is quite pedagogical to understand your point, and Mulletron's point that a cylindrical cavity with two different dielectric mediums maybe as or more effective than a truncated cone with only one medium
this is quite pedagogical to understand your point, and Mulletron's point that a cylindrical cavity with two different dielectric mediums maybe as or more effective than a truncated cone with only one medium
Quotethis is quite pedagogical to understand your point, and Mulletron's point that a cylindrical cavity with two different dielectric mediums maybe as or more effective than a truncated cone with only one medium
You can add meep to that camp. Or at least for all indications you can but I should make some controlled runs to confirm it. If I ran a truncated cone and a cylinder, what frequency and cylindrical dimensions would I use in order that it be a fair comparison to the truncated cone? Dielectric constant? Or, if you prefer, what cylinder and cone dimensions are consistent? Same resonant frequency and mode or same "size" "volume" but since we're addressing a space thruster, maybe integrated structural mass? Cylinders tend to be smaller and simpler.
@ Rodal :
See attached picture to share my mental image. Tilt over-exaggerated for illustration.
Grey : solid rotating assembly (no deformation implied)
Orange/brown : fixed assembly (no deformation implied)
Blue : the ground slab of the vacuum chamber (no deformation implied)
For now, assume a perfect axis of rotation around Z : only one degree of freedom of Grey relative to Orange, the "official" rotation around Z, no compliance implied, Grey kept in the XY plane, plane has same tilt as Orange (XY parallel to Orange platform).
@Star-Drive
Can you confirm this is a correct way to understand that there is a tilt in the axis of rotation ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=811757;image)
One aspect of this tilt in the axis of rotation that hasn't been discussed is the requirement for imbalance. The difference in moments on either side of the beam only has to be very slight for it to always come to rest at the same location +/- a micron or two.
Yes, a difference in centre of mass can make long lasting difference in position. The following statement tries to summarize rigorously :
Statement A : Any shift in centre of mass of a part (relative to fixation to the balance arm) along a direction orthogonal to a compliant (not infinite stiffness) axis that is not strictly vertical can induce a change in angular rest position around said compliant axis.
This can be quite important as a (thermal) longitudinal (Y+ or Y-) shift in CoM of the frustum assembly would be orthogonal to axis Z, but so long as this most compliant by far axis Z (the natural axis of the pendulum) was believed to be strictly vertical there would be no change in angular rest position of the arm (around Z). Only transient angular positions shifts could be induced by such thermal CoM shifts, the arm position (around Z) would be quickly enough restored to unmodified rest position (return to baseline) by the spring restoring torque of flexure bearings, and then time of ~45s during which a sustained displacement where recorded could be used as an effective argument that this couldn't be due to thermal expansions alone.
Note that now that the Z axis is no longer vertical the argument is no longer valid.QuoteA small CW tilt along the X axis of the balance arm would explain the apparent drift in the baseline seen in some of the thrust waveforms. When the cavity has the orientation shown below its CM shifts to the left. This would reduce the tilt, resulting in an increase in brightness of the reflected light the LDS measures; due to the mirror position being closer to an optimal perpendicular position wrt the light beam. The increase in brightness corresponds to a decrease in distance; hence the negative slope. With the device mounted the other way the shift in CM increases the tilt. This reduces the reflected light and is registered as an increase in distance.
Is this what you are saying ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=809643;image)
Indeed the X axis is not vertical (it is horizontal, or almost), so the above statement A does apply if we consider rotations around X are not against infinite stiffness. But preliminary rough estimations gave me relative displacements of rest optical length of at least one order of magnitude below signal. Even if not infinitely stiff, the added torsion compliance of faztek beam around X and compliance of tandem flexure bearings around X is not enough. For reasonable thermal CoM's shifts, this is stiff enough , and the optical lever is small enough (optical length d measured at small distance below X) that it would make very little contribution to the signal.QuoteNo actual motion of the beam occurs. This apparent motion is an optical artifact. This assumes the Philtec distance sensor is used on the far side. If it is used on the near side a small CCW tilt along the X axis of the beam would produce the same effect; except requiring much less rotation from the change in CM.
For this twist around X effect, no actual rotation of the beam around Z would occur, but the beam is deformed. I wouldn't qualify that as an "optical artifact". Sorry I'm becoming quite finicky on wordings lately :) That would be a real mechanical motion, only not a motion around the "official" Z axis.
We have all reasons to believe the Philtec linear sensor is used in the far range, see attached chart's horizontal units. The initial report (anomalous...) clearly states that it is used around 500µm, the vertical readings of the charts are consistent, and Paul March confirms :......
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
...
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
...
Still, there is a factor 10 disparity between the apparent stiffness readings (LDS readings against calibrations pulses alone) and the stiffness needed to explain the 4.5s pseudo-period of oscillations, so this can put a doubt on the readings of vertical scale, a factor 10 here could explain a lot of things.
Regardless of this nagging problem of late, now that we know that Z deviates from strict verticality by a quarter bubble, from statement A above there is now a real possibility that a thermal CoM shift along Y changes angular rest position around the official Z, of relative magnitude compatible with signals, as rotation around Z has a very low stiffness (the restoring torque of flexure bearing around their natural axis of rotation). And such change in angular rest position around Z would record as false "sustained thrusts" in the charts.
Statement B : The validity of real sustained thrust signals now rests on the amount of deviation of Z from vertical, resolution of the contradictions between apparent stiffness around Z, and careful assessment of thermal expansions in vacuum. The sustained duration alone no longer suffice.
For this twist around X effect, no actual rotation of the beam around Z would occur, but the beam is deformed. I wouldn't qualify that as an "optical artifact". Sorry I'm becoming quite finicky on wordings lately :) That would be a real mechanical motion, only not a motion around the "official" Z axis.
We have all reasons to believe the Philtec linear sensor is used in the far range, see attached chart's horizontal units. The initial report (anomalous...) clearly states that it is used around 500µm, the vertical readings of the charts are consistent, and Paul March confirms :......
- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.
...
The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached.
...
Still, there is a factor 10 disparity between the apparent stiffness readings (LDS readings against calibrations pulses alone) and the stiffness needed to explain the 4.5s pseudo-period of oscillations, so this can put a doubt on the readings of vertical scale, a factor 10 here could explain a lot of things.
Regardless of this nagging problem of late, now that we know that Z deviates from strict verticality by a quarter bubble, from statement A above there is now a real possibility that a thermal CoM shift along Y changes angular rest position around the official Z, of relative magnitude compatible with signals, as rotation around Z has a very low stiffness (the restoring torque of flexure bearing around their natural axis of rotation). And such change in angular rest position around Z would record as false "sustained thrusts" in the charts.
Statement B : The validity of real sustained thrust signals now rests on the amount of deviation of Z from vertical, resolution of the contradictions between apparent stiffness around Z, and careful assessment of thermal expansions in vacuum. The sustained duration alone no longer suffice.
Same here. The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.
Same here. The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.
I've decided to try and live up to my screen name and throw my lot in with the replicators. I have a few questions before I kick off my effort:
1) Why did you decide to go with #201065780928 rather than a frustrum of a cone? The #201065780928 part looks more like a rectangular slit shape rather than a cone shape.
2) How do you plan on hooking the MA86751B X band oscillator up to the waveguide assembly?
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC. Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
5) Do you plan on putting a dielectric toward one end of the waveguide assembly?
6) With what material do you plan on capping each end of the waveguide assembly?
Although I direct this friendly set of questions to Notsosureofit, Mulletron, and others who are attempting replications, I welcome any forum members to chime in with recommendations or insights. Can you imagine what would happen if the effect can be shown on such a small scale? It could cause some ripples and raise a quite a few eyebrows around the world.
Same here. The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.
I've decided to try and live up to my screen name and throw my lot in with the replicators. I have a few questions before I kick off my effort:
1) Why did you decide to go with #201065780928 rather than a frustrum of a cone? The #201065780928 part looks more like a rectangular slit shape rather than a cone shape.
2) How do you plan on hooking the MA86751B X band oscillator up to the waveguide assembly?
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC. Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
5) Do you plan on putting a dielectric toward one end of the waveguide assembly?
6) With what material do you plan on capping each end of the waveguide assembly?
Although I direct this friendly set of questions to Notsosureofit, Mulletron, and others who are attempting replications, I welcome any forum members to chime in with recommendations or insights. Can you imagine what would happen if the effect can be shown on such a small scale? It could cause some ripples and raise a quite a few eyebrows around the world.
....That would also be my first choice: a long pendulum with damping provided by an oil bath. The experiment used by Brito, Marini and Galian (they had battery power, self-contained) to nullify a Mach Lorentz Thruster:
I'll just try a long ( 20 ft ?) pendulum First and see what happens. Vacuum later.
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
...
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Unless your cavity has an unusually small diameter, the problem with 9.9 GHz to 10.6 GHz will be a luxury of resonances rather than a scarcity of natural frequencies: there may be too many resonant frequencies very close to each other at such a high frequency and therefore difficult to keep the cavity resonating in a pure mode.Same here. The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.
I've decided to try and live up to my screen name and throw my lot in with the replicators. I have a few questions before I kick off my effort:
....
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC. Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
.....
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
...
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Mulletron,
Can you provide me with the contact information (email) of the maker of the custom cone? What dimensions did you settle on? I appreciate that you are footing the bill for the layout, thereby lowering the cost for the rest of us. Kudos to you for that.
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120
Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.
Got about an oz of very expensive liquid metal from here:
http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstan
So back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742
...
Been working with the supplier with a machine shop I posted about way back:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669
I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these:
(https://lh4.googleusercontent.com/xpJIaQNfcmecDoHrIDnoYqVs1ccOghkxSpkgXhJ8MrnoyaK61MQ9rSfiBnuIhyayCIIEaQ=w1549-h745)
but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Mulletron,
Can you provide me with the contact information (email) of the maker of the custom cone? What dimensions did you settle on? I appreciate that you are footing the bill for the layout, thereby lowering the cost for the rest of us. Kudos to you for that.
The cone is the same dims as the DUT at Eagleworks. What was built was based off of this: https://docs.google.com/file/d/0B4PCfHCM1KYoN2VURmltbVlfa3c/edit?pli=1
It is in shipping to me att. I intend to make sure it is good to go, then if no changes are required, the guy who made it will list it on Ebay for around 50 bucks or so. Please give it a few days to arrive. I want to make sure there aren't any problems before it gets put up for sale. That way I accept the risk first. Here's what it looks like.
....
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC. Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
.....
...
I don't think the tilt of the balance beam about the X axis would have to be very much for the resulting change in received light amplitude to register as a shift in position. The LDS has fractional micron resolution. Assuming the light pattern from the fiber optic cable has a circular gaussian distribution, for any given distance the maximum light level hitting the detector is when the plane of the mirror is perpendicular to the central axis of the light beam. Any small deviation ( arc-second) will reduce the light amplitude; which registers as a displacement. It is impossible to align the LDS perfectly so the angle between the mirror and the light beam is never exactly 90 degrees in X and Y. The expansion of the cavity due to heating has a very long time constant. The slow drift in the position between RF pulses looks like a thermal response.
Prior to a test run data take, the LDS is positioned to a known displacement datum (usually 500 micrometers) via mechanical adjustments to its mounting platform. Gross adjustments are performed via set screws. Fine adjustments are performed using manually - operated calibrated screw mechanisms and a remotely controlled motorized mechanism that can be operated with the chamber door closed and the chamber at vacuum. The remote adjustment capability is necessary since the LDS datum will change whenever a change to the test facility environment affects the roll - out table or the chamber – e.g., whenever the chamber door is closed or latched and whenever the chamber is evacuated. Once the LDS displacement is adjusted in the final test environment, further adjustment between test run data takes is usually not required.
Same here. The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.
I've decided to try and live up to my screen name and throw my lot in with the replicators. I have a few questions before I kick off my effort:
1) Why did you decide to go with #201065780928 rather than a frustrum of a cone? The #201065780928 part looks more like a rectangular slit shape rather than a cone shape.
2) How do you plan on hooking the MA86751B X band oscillator up to the waveguide assembly?
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC. Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
5) Do you plan on putting a dielectric toward one end of the waveguide assembly?
6) With what material do you plan on capping each end of the waveguide assembly?
Although I direct this friendly set of questions to Notsosureofit, Mulletron, and others who are attempting replications, I welcome any forum members to chime in with recommendations or insights. Can you imagine what would happen if the effect can be shown on such a small scale? It could cause some ripples and raise a quite a few eyebrows around the world.
1. it matches the osc. waveguide and 1st cheap one on EBay.
2. just bolt them together
3. I had this one already
4. probably, have to calculate when I get the waveguide
5. that's an option
6. TBD flat pate, detector fitting etc etc
I'll just try a long ( 20 ft ?) pendulum First and see what happens. Vacuum later.
...
Frobnicat:
Your analysis and comments made me go back and look at the current alignment of the Eagleworks torque pendulum and the attached picture indicates that my recollection of the leveling of the bottom beam of the TP being a quarter bubble high at the vacuum chamber door end was a bit exaggerated due to parallax error and a just plain bad memory. It looks now like less than tenth of bubble low at the door end of the vacuum chamber, but part of that apparent tilt may in reality be due to actual bending of the 1.50 inch square aluminum beam.
Best, Paul M.
@ RODALThe force derivation for a truncated cone seems to have been of a physical, intuitive character (if not so, please correct me). From a physical standpoint, one can observe the following:
Still struggling as to how to get the exact equation into the form;
f^2 = k^2 + [asymmetric terms(x)] such that, (f(0)^2 - f(L)^2) = [asymmetric terms(0)] - [asymmetric terms(L)]
That is, how to evaluate at constant k. Any ideas ?
@Mulletron and @Star-Drive advocate dielectrics inside these microwave cavity resonators.@ RODALThe force derivation for a truncated cone seems to have been of a physical, intuitive character (if not so, please correct me). From a physical standpoint, one can observe the following:
Still struggling as to how to get the exact equation into the form;
f^2 = k^2 + [asymmetric terms(x)] such that, (f(0)^2 - f(L)^2) = [asymmetric terms(0)] - [asymmetric terms(L)]
That is, how to evaluate at constant k. Any ideas ?
1) My understanding of your prior derivation is that it modeled the truncated cone as being traveled by plane waves (*), just like a plane wave travels a cylindrical cavity from one end to the other. The difference is that in the truncated cone, the plane wave continuously, gradually experiences a lower natural frequency as it travels from the small diameter (cross-section with the highest natural frequency) end to the big diameter end (cross-section with the lowest natural frequency). It should also continuously, gradually experience attenuation (loss in intensity) as it travels from the small end to the big end.'
___________
(*) Note: truncated cones have spherical waves traveling inside them, rather than plane waves. So the model assumes a very large radius of curvature, such that the spherical wave is approximately flat.
CONICAL PIPES (like the truncated cone: continuous gradual change in diameter)
(http://i00.i.aliimg.com/wsphoto/v0/1546678994/carbon-conical-welded-steel-tubes.jpg)
2) The behavior in a cylindrical pipe containing two dielectric mediums is fundamentally different: instead of the continuous, gradual change in natural frequency of the truncated cone, the cylindrical pipe containing two dielectric mediums experiences a discontinuous, step-change, a brutal change, going from medium 1 to dielectric medium 2. This would be more like a pipe experiencing a discontinuous step-change in diameter all of a sudden, causing a sudden change in natural frequency and a sudden change in attenuation.
STEP-PIPE (the geometrical analog of the discontinuous step-change produced by a pipe having two dielectric mediums)
(http://www.feked.com/images/detailed/28/reducer_2.jpg)
I know its a stretch thinking this fits in here but you guys have to see this: http://www.sciencedaily.com/releases/2015/03/150306091617.htm
because QM and GRT reconciled? and gravitons. mustn't forget gravitons.
2) The behavior in a cylindrical pipe containing two dielectric mediums is fundamentally different: instead of the continuous, gradual change in natural frequency of the truncated cone, the cylindrical pipe containing two dielectric mediums experiences a discontinuous, step-change, a brutal change, going from medium 1 to dielectric medium 2. This would be more like a pipe experiencing a discontinuous step-change in diameter all of a sudden, causing a sudden change in natural frequency and a sudden change in attenuation.
Interesting hypothesis. You say that in this case the LDS readings would be more sensitive to a change in angle of the reflective mirror than a change in distance. The LDS is a small distance below the X axis, so a small angular deviation around X would amount to tiny displacement (d' - d) but the small angular deviation would itself tilt the mirror and that could change the LDS readings that is roughly proportional to the reflected light.
But then this coupling between angular effect and displacement would also be present for the main movements around Z. LDS is at 35cm from Z axis, I would say it is one order of magnitude more than the distance of mirror below X axis, the lever effect of displacement/angle ratio would be lower (less angle for same displacement) but still if angle deviation is to have a significant effect in case around X it should also have a significant effect around Z.
I read "most materials : including smooth but scattering surfaces", not only mirrors. Actually, mirrors may be a very special case. My question is now if the gain control of the system is consistent with the use of a mirror reflecting target. As seen qualitatively from attached figure : a perfect mirror would bounce back in the signal detector a lot more photons than a matte white. If the gain is calibrated against matte material (say, as hypothesis, default factory settings) the baseline distance from the mirror to have a tension that shows as 500µm would be much greater than 500µm.
Edit : BTW, how comes that at some very near distance there start to be less photons bouncing back in the signal detector ? Thank zen-in for bringing up interesting questions about LDS...
2) The behavior in a cylindrical pipe containing two dielectric mediums is fundamentally different: instead of the continuous, gradual change in natural frequency of the truncated cone, the cylindrical pipe containing two dielectric mediums experiences a discontinuous, step-change, a brutal change, going from medium 1 to dielectric medium 2. This would be more like a pipe experiencing a discontinuous step-change in diameter all of a sudden, causing a sudden change in natural frequency and a sudden change in attenuation.
Yes, the case of a gradually changing dielectric constant is very similar to that of the tapered cavity.
The step-change involves a much more complicated situation w/ the necessity of including the reflected waves from the discontinuity. But, it may well offer enhanced performance. (?) ....
...maybe he envisions this device as some sort of 'turbo-charger?' That is something that adds to an already existing velocity, but won't function well, if at all when 'at rest.' ...A turbocharger, is a device that increases an engine's efficiency and power by forcing extra air into the combustion chamber.
What is the "engine" that the EM Drive is turbocharging?
The bizarre nature of something needing to be free to accelerate for it to produce a force doesn't apply to the turbocharger or to the engine: the engine that is being turbocharged does not need to be accelerating or even be in rigid body motion. Its center of mass can be completely stationary, and the turbocharged engine can then be used for electric power generation, for example, instead of for transporting people as in an automobile.
...
I don't think the tilt of the balance beam about the X axis would have to be very much for the resulting change in received light amplitude to register as a shift in position. The LDS has fractional micron resolution. Assuming the light pattern from the fiber optic cable has a circular gaussian distribution, for any given distance the maximum light level hitting the detector is when the plane of the mirror is perpendicular to the central axis of the light beam. Any small deviation ( arc-second) will reduce the light amplitude; which registers as a displacement. It is impossible to align the LDS perfectly so the angle between the mirror and the light beam is never exactly 90 degrees in X and Y. The expansion of the cavity due to heating has a very long time constant. The slow drift in the position between RF pulses looks like a thermal response.
Interesting hypothesis. You say that in this case the LDS readings would be more sensitive to a change in angle of the reflective mirror than a change in distance. The LDS is a small distance below the X axis, so a small angular deviation around X would amount to tiny displacement (d' - d) but the small angular deviation would itself tilt the mirror and that could change the LDS readings that is roughly proportional to the reflected light.
But then this coupling between angular effect and displacement would also be present for the main movements around Z. LDS is at 35cm from Z axis, I would say it is one order of magnitude more than the distance of mirror below X axis, the lever effect of displacement/angle ratio would be lower (less angle for same displacement) but still if angle deviation is to have a significant effect in case around X it should also have a significant effect around Z.
Unfortunately the documentation for the Philtec D63 displacement sensor (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=810350) seems to give no information on reflective surface angular deviation impact on measurements. It indicates Ø 1.6 mm Target Spot Size. This is 3 times more than nominal operating distance of 500µm (0.5mm) so your drawing is a bit misleading with proportions. In reality the reflected dot is big relative to distance from reflector, would an angular deviation still impact the amount of light swallowed back ?
Is it you drawing or you found it elsewhere ? I ask the question because you mention the reflecting surface as being mirror. It does appear as a mirror in the pictures of pendulum at Eagleworks and this is stated explicitly in Brady's report page 3 (together with that LDS is photon time of flight, which is not, but let's proceed). But I don't find in the D63 documentation that a mirror should or could be used. It does say that These specifications represent best case performance where: the target is flat, smooth and highly reflective
This implies that the target may not be highly reflective (at the cost of decreased performance) but does highly reflective imply that a mirror is the best case ? My reading (but I'm not native English reader) is that reflective can mean a matte white material, that is a surface that does bounce near 100% of incoming photons, but in a more or less scattering manner, not necessarily as per perfect reflection. See attached picture : top the situation at hand at Eagleworks, bottom the default situation for which the LDS might be initially calibrated.
This could explain a lot about the disparity between vertical readings in the charts and stiffness parameters : when charts indicate ~1µm LDS deviation for 29.1µnN calibration pulses for instance, all could be much better explained and consistent if it meant 10µm instead.
To me there is no doubt that the LDS is operating in the far range : the cal. pulses are attractive by nature, and correspond to a displacement to the right (Y+) and that lowers the measured distance, as in the charts. Also operating in the near range would not only reverse this consistent orientation but would also increase the sensitivity : that would go against what is to be explained (apparent higher µm/µN stiffness than compatible with other known parameters, for 2 separate predictions from the dynamic periods of oscillations and the known stiffness of flexure bearings)
So, what anyone wanting to understand clearly the charts need is a way to explain a reduced sensitivity of the LDS, that would show 1µm displacement when in fact it is 10µm. Following on the D63 doc, there is a calibration procedure :
The effect of changing target reflectance is to shift the voltage output higher or lower. Factory calibrations have
the Peak Voltage set to 5.000 volts. A gain control is provided for calibration of the sensor output to various target surfaces. In-situ calibration is performed simply, by adjusting the sensors tip-to-target gap until the peak output voltage is attained, and then by using the gain control to set the peak voltage to full scale (5.000 volts). After setting the peak to 5 volts, the factory gap calibration chart applies for the target being measured. This procedure allows the sensor to be used to perform precision linear motion measurements on most materials.
I read "most materials : including smooth but scattering surfaces", not only mirrors. Actually, mirrors may be a very special case. My question is now if the gain control of the system is consistent with the use of a mirror reflecting target. As seen qualitatively from attached figure : a perfect mirror would bounce back in the signal detector a lot more photons than a matte white. If the gain is calibrated against matte material (say, as hypothesis, default factory settings) the baseline distance from the mirror to have a tension that shows as 500µm would be much greater than 500µm.
The protocol of tuning for nominal 500µm distance between optical fibre head and mirror is on page 3 of Brady et al report (anomalous...) :Quote from: Brady et al. Anomalous thrust...Prior to a test run data take, the LDS is positioned to a known displacement datum (usually 500 micrometers) via mechanical adjustments to its mounting platform. Gross adjustments are performed via set screws. Fine adjustments are performed using manually - operated calibrated screw mechanisms and a remotely controlled motorized mechanism that can be operated with the chamber door closed and the chamber at vacuum. The remote adjustment capability is necessary since the LDS datum will change whenever a change to the test facility environment affects the roll - out table or the chamber e.g., whenever the chamber door is closed or latched and whenever the chamber is evacuated. Once the LDS displacement is adjusted in the final test environment, further adjustment between test run data takes is usually not required.
How this displacement of 500µm is known ? Has the procedure followed the step (as per D63 documentation) of homing to the distance corresponding to peak signal (whatever it's absolute level), calibrating the gain so that at this peak the signal is now 5V, and then stepping back until meeting ~4.3 V corresponding to 500µm nominal distance ? If this was not followed, or if the D63 is not mean to be operated with perfect mirror target (doubtful it wouldn't be mentioned in documentation, but who knows ?), it is possible the LDS is operating in a far range that has a much lower sensitivity (and linearity) than the nominal -2.7 mv/µm.
Edit : BTW, how comes that at some very near distance there start to be less photons bouncing back in the signal detector ? Thank zen-in for bringing up interesting questions about LDS...
Folks:
The Philtec fiber-optic cable used in their D63 reflective displacement sensor uses TWO (2) fiber optic bundles in the armored cable with one bundle being used as the transmit and the other bundle the receiver. A description of how Philtec uses these two fiber-optic bundles to measure a distance with sub-micron resolutions is provided at their website:
http://www.philtec.com/downloadssupport/documentlibrary/documents/applicationnotes/AboutTheSensors.pdf
Hope that helps
Best, Paul M.
2) The behavior in a cylindrical pipe containing two dielectric mediums is fundamentally different: instead of the continuous, gradual change in natural frequency of the truncated cone, the cylindrical pipe containing two dielectric mediums experiences a discontinuous, step-change, a brutal change, going from medium 1 to dielectric medium 2. This would be more like a pipe experiencing a discontinuous step-change in diameter all of a sudden, causing a sudden change in natural frequency and a sudden change in attenuation.
Yes, the case of a gradually changing dielectric constant is very similar to that of the tapered cavity.
The step-change involves a much more complicated situation w/ the necessity of including the reflected waves from the discontinuity. But, it may well offer enhanced performance. (?) These types of calculations have been done w/ iterative matrix math. I'm going to try some ideas w/ programs I have to see if I can get a better feel for this case. (1D calculations at least)
Added: 1D modes suggest that we only have to consider terms which contain b (ie. X or X') The others are plain waves and cancel.
Folks:
The Philtec fiber-optic cable used in their D63 reflective displacement sensor uses TWO (2) fiber optic bundles in the armored cable with one bundle being used as the transmit and the other bundle the receiver. A description of how Philtec uses these two fiber-optic bundles to measure a distance with sub-micron resolutions is provided at their website:
http://www.philtec.com/downloadssupport/documentlibrary/documents/applicationnotes/AboutTheSensors.pdf
Hope that helps
Best, Paul M.
That would explain the near side of the response curve better than my theory. The response to small angular shifts of the mirror would be similar. If the change in CM from heating caused the angle of the mirror to shift closer to a perpendicular wrt to the LDS, it would register as a decreasing displacement. This is an attempt to explain the small negative deviations in position as shown in the curve below.
If the change in CM from heating caused the angle of the mirror to shift closer to a perpendicular wrt to the LDS, it would register as a decreasing displacement.
The Philtec datasheets describe the RC type distance sensors (RC90, etc) as having 2 adjacent bundles of fibers. The distance sensor used by Eagle Labs is a D63. For a Philtec sensor with 2 bundles of fibers the change in output voltage due to an angular change is dependent on the orientation of the sensor.
Whether the small negative slope in the thrust waveform after RF power is applied is from a change in CM causing a tilt in the mirror or is actually a displacement is impossible to determine emperically.
However it is there - along with the anomalous thrust signature, the magnetic interaction at 5.6 A., and the calibration waveforms from the capacitor. Maybe what looks like a thermally induced drift is just random movement.
In the Aug. AIAA paper one of the thrust waveforms (shown below) has an unusual shape. It is bracketed by 300 V. calibration pulses on the capacitor. The calibration pulses have some overshoot/undershoot and ringing that are the typical response of an underdamped system to step responses. This response is determined by the time constant and damping of the apparatus and should not change whatever the driving function is. For example if a fly bumped into the TP and imparted the same momentum as the capacitor with its 300V did, the response should be virtually identical. So why is the response from the RF being switched on and then off (anomalous thrust) so different?
Yes this fig. 22 chart (TE012, 2.6W, 55.4µN reported) is unusual, not time stamped, no vertical scale indications, cal. pulses at 300V 60.1µN instead of the usual 200V 29.1µN (note the non relative proportionality), and very smooth rises and falls for thrust pulses compared to cal. pulses. The overshoot and undershoot would be the same for responses to step rises and falls. The most likely explanation for the lack of ringing for the thrust pulse compared to cal. pulses is that the thrust case the driving function would not be steplike. That particular chart was discussed in thread 1 : http://forum.nasaspaceflight.com/index.php?topic=29276.msg1280094#msg1280094. And even for more "ringing" thrusts responses (more consistent with cal. pulses, like in fig.19) there is still not enough ringing to be explained by a pure step thrust. See bottom pic. in this link (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1280037#msg1280037) to have an idea of what might be the shape of the driving function to explain that. My recollection is that all this semi-quantitative reasoning on relative ringing overshoots hasn't reached general consensus.
FYI
Just to get a feel for dielectrics I tried the straight cylinder with a uniform dielectric variation from end to end.
Using the same simpleminded approximation as the tapered cylinder gives:
del f = ( f/(2*c^2)) * (c1^2-c2^2)
T = (h*f/(2*L*c^2)) * (c1^2-c2^2)
NT = (P*Q/(4*pi*L*f*c^2)) * (c1^2-c2^2)
Which is a lot simpler than I might have expected. Perhaps the approximation is too simple or it represents a special case with " uniform dielectric variation from end to end " rather than a straight conical insert.
In any case, it seems to be telling me to look for the proper integral form to be doing these.
Well, this isn't going to work for a step function the way it is. We need to find the integral representation along the axis to be able to do that. This is only a close (?) approx for the uniform variation.
L may go down but f goes up.......
c is the only thing that varies here (no step)
Might try a fourier expansion next. Have to think about that.....
ADDED: Can you generate f^4 for the step function? Hard to do by hand on Post-it Notes !
An intriguing possibility for further increasing the
magnitude of the force is slow-light enhancement,
since the force increases as 1/vg for fixed input power.20
We note that the electrostatic force due to
trapped or induced charges in Si waveguides is esti-
mated to be at least an order of magnitude smaller
than the optically induced force. The Casimir–
Lifshitz force is even smaller. Optical evanescent ...
That is a good thread BTW. Those guys are harsh and I like it. I value reading outside opinions because I don't want to get caught up in my own little bubble and lose insight, like I did for a large part of thread 1.Not up to NSF standards, so hopefully if some of them decide to contribute they won't get this thread locked like thread #1.
I came across an interesting bit of information while doing background reading on evanescent wave forces.QuoteAn intriguing possibility for further increasing the
magnitude of the force is slow-light enhancement,
since the force increases as 1/vg for fixed input power.20
We note that the electrostatic force due to
trapped or induced charges in Si waveguides is esti-
mated to be at least an order of magnitude smaller
than the optically induced force. The Casimir–
Lifshitz force is even smaller. Optical evanescent ...
Quoting from this document:
http://math.mit.edu/~stevenj/papers/PovinelliLo05.pdf (http://math.mit.edu/~stevenj/papers/PovinelliLo05.pdf)
We've been laser-focused on materials with greater dielectric constants, but what about materials with similar dielectric constants, like fused quartz? Will the EM drives behave differently?
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
We've been laser-focused on materials with greater dielectric constants, but what about materials with similar dielectric constants, like fused quartz? Will the EM drives behave differently?
If Paul March discussed testing with dielectric materials other than Teflon and HD PE, I don't recall. It would be interesting if Paul could comment (or if Paul already discussed this, if somebody could bring the experimental results to our attention).
I understand that Roger Shawyer tested non-polymer materials as dielectrics, but the specific results and the dimensions and material properties of the dielectrics tested were not disclosed (again, if anyone has more specific details, please bring them to our attention).
I really wish I could get somebody else on board with this idea because I absolutely will fail on my own.
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
With the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End.
@Star-Drive :
I'm still asking about the huge discrepancy (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1342605#msg1342605) between the expected linear displacement of 32.3µm (assuming only flexure bearings restoring torque) in response to a calibration pulse of 29.1µm and the actual readings on chart vertical scale of a linear displacement between 1µm to 2.5µm for the calibration pulses.
There is an inconsistency of an order of magnitude between values as expected from flexure stiffness and as recorded on the display. Is it acknowledged or investigated by the team at Eagleworks ?
I'm not objecting that the thrusts measurements would not be proportional (ie for twice the deviation of cal. pulse => twice 29.1µN) but since the fixed ratio of µm displacement per µN of thrust is at the heart of the experiment, such discrepancy can only weaken the case for the charts published so far. This needs to be clarified anyhow. It could be a problem of calibration of the Philtec D63 gain, or a biased scaling factor between the analog outputs of the D63 and the final rendering of vertical scale on display...
I see the wisdom in your hint that we should approach this starting from an earlier point, with the resonating field as a function of the longitudinal polar coordinate variable. In the case of only one dielectric the field is just a harmonic function of the longitudinal variable, hence your idea to perhaps do a Fourier series expansion.@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
With the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End.
By keep the diameter of the Small End constant, increase the large end of the cavity, in order to have the same resonant frequency, cavity height must be reduced, quality factor also reduce.
http://www.emdrive.com/NWPU2010translation.pdfOK, I took a look at the above quotations.
In the conclusion area, last sentence in 3rd paragraph, next to last page.QuoteWith the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End.
Seems to be a summary of this on page 8:QuoteBy keep the diameter of the Small End constant, increase the large end of the cavity, in order to have the same resonant frequency, cavity height must be reduced, quality factor also reduce.
@Star-Drive :
I'm still asking about the huge discrepancy (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1342605#msg1342605) between the expected linear displacement of 32.3µm (assuming only flexure bearings restoring torque) in response to a calibration pulse of 29.1µm and the actual readings on chart vertical scale of a linear displacement between 1µm to 2.5µm for the calibration pulses.
There is an inconsistency of an order of magnitude between values as expected from flexure stiffness and as recorded on the display. Is it acknowledged or investigated by the team at Eagleworks ?
I'm not objecting that the thrusts measurements would not be proportional (ie for twice the deviation of cal. pulse => twice 29.1µN) but since the fixed ratio of µm displacement per µN of thrust is at the heart of the experiment, such discrepancy can only weaken the case for the charts published so far. This needs to be clarified anyhow. It could be a problem of calibration of the Philtec D63 gain, or a biased scaling factor between the analog outputs of the D63 and the final rendering of vertical scale on display...
Frobnicat & Crew:
Dr. White and his NASA interns are the folks who performed the original force calibration work on this torque pendulum, so your questions might be bettered answered by him. However, it's my understanding that the torque pendulum's actual micron displacement observed for each test run is dependent on its specific total active mass load, balance weights and all their locations on the torque pendulum arm for the test run in question. So as long as we reference the near constant calibration force from our electrostatic fin calibration system before and after each test run, and then use that specific displacement yardstick of the moment as the true measure of the test article's generated forces, it doesn't matter what the actual micron displacement turns out to be for each data run. And that has been what we've used to date report our generated forces. If there is a major problem with that approach please let us know.
Best, Paul M.
We've been laser-focused on materials with greater dielectric constants, but what about materials with similar dielectric constants, like fused quartz? Will the EM drives behave differently?
If Paul March discussed testing with dielectric materials other than Teflon and HD PE, I don't recall. It would be interesting if Paul could comment (or if Paul already discussed this, if somebody could bring the experimental results to our attention).
I understand that Roger Shawyer tested non-polymer materials as dielectrics, but the specific results and the dimensions and material properties of the dielectrics tested were not disclosed (again, if anyone has more specific details, please bring them to our attention).
Dr. Rodal:
We've only tried polyethylene, Teflon, neoprene rubber and aluminum oxide discs so far, with PE and PTFE being the most productive. However what dielectric if any will prove to be optimal in generating the most thrust in these EM-Drive like thrusters is really dependent on what physics is really driving their operation. So far the dielectrics with the largest electrostrictive coefficient combined with a largest Q-factor appear to be the winners. This implies to me that fused quartz may be a good candidate, since it has a large Q-factor with moderate electrostrictive coefficient and piezoelectric responses.
BTW, these dielectrics may prove to be the E&M/gravity field to mechanical converters needed to generate thrust. On the other hand if Shawyer and the Chinese are right in their statements that they used no dielectrics in their tens to hundreds of milli-Newton thrusters, then these dielectrics may just be means of amplifying the underlying effects that are generated just by the action of the E&M fields on the copper or silver atoms in the walls of the frustum resonant cavity. Remember that though copper and silver only have a real permittivity of 1.0, in temporal space they have a complex permittivity of greater than 100. and this is the parameter that drives E to B-field phase shifting over very small distances at microwave frequencies, (~2 microns deep at 2.0 GHz). I.e. these metallic atoms can undergo very large cyclic accelerations around their crystal lattice positions as the E&M wave fronts are dissipated in them.
I really wish I could get somebody else on board with this idea because I absolutely will fail on my own.
I'm sorry that I can't be of much help in this area, but for what it's worth, I think your theories are worth exploring by those who have the knowledge, background, and ability to do so.
@Dr. Rodel - Did you use your magic formulas to calculate the resonance frequencies of the newest Eagleworks cavity from Paul? Including dielectric effects? If so, what were the numbers?I obtained exact solutions so far for:
@Dr. Rodel - Did you use your magic formulas to calculate the resonance frequencies of the newest Eagleworks cavity from Paul? Including dielectric effects? If so, what were the numbers?I obtained exact solutions so far for:
1) Truncated cone with only one dielectric medium in the cavity
2) Cylindrical cavity with two dielectric coupled mediums
I haven't had the time to derive the formula for the Truncated Cone with two dielectric mediums to consider the case with vacuum and HD-PE.
I did calculate the Eagleworks cavity without the HD-PE dielectric section.
I did calculate the Eagleworks cavity without the HD-PE dielectric section.
....See http://forum.nasaspaceflight.com/index.php?topic=36313.msg1339803#msg1339803QuoteI did calculate the Eagleworks cavity without the HD-PE dielectric section.
And what number did you get?
....See http://forum.nasaspaceflight.com/index.php?topic=36313.msg1339803#msg1339803QuoteI did calculate the Eagleworks cavity without the HD-PE dielectric section.
And what number did you get?
The frequency for the TM221 mode shape (without the dielectric) is 2.00709 GHz.
Is there another particular mode you are interested to know the frequency for?
....See http://forum.nasaspaceflight.com/index.php?topic=36313.msg1339803#msg1339803QuoteI did calculate the Eagleworks cavity without the HD-PE dielectric section.
And what number did you get?
The frequency for the TM221 mode shape (without the dielectric) is 2.00709 GHz.
Is there another particular mode you are interested to know the frequency for?
I'll need to think on that. It seems, from the images you posted, that the mode is the same for you and Eagleworks. So what (if anything) is close to freq = 1.937115E+009 Hz? And was the Eagleworks photos taken with that drive frequency?
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
....See http://forum.nasaspaceflight.com/index.php?topic=36313.msg1339803#msg1339803QuoteI did calculate the Eagleworks cavity without the HD-PE dielectric section.
And what number did you get?
The frequency for the TM221 mode shape (without the dielectric) is 2.00709 GHz.
Is there another particular mode you are interested to know the frequency for?
I'll need to think on that. It seems, from the images you posted, that the mode is the same for you and Eagleworks. So what (if anything) is close to freq = 1.937115E+009 Hz? And was the Eagleworks photos taken with that drive frequency?
Take a look at the enclosed report from Paul March for a mode which NASA's COMSOL analyst identified as TM112 "like TM110 at top, and TM111 at bottom" with a frequency of 1.9355 GHz.
I only calculated a few modes.
Regarding your question "And was the Eagleworks photos taken with that drive frequency?" I presume that the photo was taken for the EM Drive with a dielectric (which would give a slightly lower frequency) while my computation was without the dielectric.
@Rodal
Can there be a resonance in the empty cavity at the low frequency of 1.6859 GHz?
....
Dr. Rodal:
....
Acknowledge that "neoprene" rubber covers a multitude of formulations, but it turns out that most if not all of them have low Q-factors at microwave frequencies that disqualify them from this application even if they have a large electrostrictive coefficient. What counts in this low power EM-drive dielectric "amplifier" appears to be a dielectric with the largest electrostrictive/piezoelectric coefficient combined with a high Q-factor at microwave frequencies.
Best, Paul M.
....Dr. Rodal:
....
Acknowledge that "neoprene" rubber covers a multitude of formulations, but it turns out that most if not all of them have low Q-factors at microwave frequencies that disqualify them from this application even if they have a large electrostrictive coefficient. What counts in this low power EM-drive dielectric "amplifier" appears to be a dielectric with the largest electrostrictive/piezoelectric coefficient combined with a high Q-factor at microwave frequencies.
Best, Paul M.
Paul,
(*) Neoprene® is Dupont's trade name for Chloroprene rubber (CR), so in the rest of this post I will refer to it by its technical name Chloroprene rubber (CR).
The fact that NASA Eagleworks tested a dielectric made of Chloroprene rubber (CR) and found out that this rubber material is "disqualified for this (EM Drive) application" because the measured thrust using this rubber material as a dielectric is insignificant compared to using PTFE or HD-PE has important consequences that should be pointed out.
Since Chloroprene rubber (CR) has a coefficient of thermal expansion up to 158% greater than the coefficient of thermal expansion of HD PE:
THERMAL EXPANSION
Chloroprene rubber (CR) 125*10^(-6) to 190*10^(-6) 1/(deg K) http://techcenter.lanxess.com/docs/pdft/e5-14.pdf
High Density Polyethylene (HD PE) 120*10^(-6) 1/(deg K)
http://www.engineeringtoolbox.com/pipes-temperature-expansion-coefficients-d_48.html
This experimental finding further nullifies @frobnicat's conjecture that the experimental measurements are an artifact due to thermal expansion of the dielectric.
(According to @frobnicat's conjecture, based on thermal expansion, under no condition should the thrust force measurement have been smaller for Chloroprene rubber (CR) than for HD PE)
(*)
LIST of MANUFACTURER TRADENAMES for Chloroprene rubber (CR)
Lanxess (Bayer AG) BAYPRENE
Denka Kagaku Kogyo CHLOROPRENE
Showa Denko SHOPRENE
TOSOH Corporation SKYPRENE
DuPont NEOPRENE
http://en.wikipedia.org/wiki/Chloroprene
Hey fellas, long time lurker, first time poster here.
I'm not even going to pretend to understand half the maths that have been tossed around in this thread. I'm in complete awe of the work you guys have been doing to solve this mystery. I do have a question though, and forgive me for my ignorance.
Does anyone know if this effect scales with the size of the frustum? Could the frequency of the microwaves be adjusted to allow the same level of force in a microscopic frustum that is shown Nasa's macroscopic frustum? If this is the case, would a sequence of many millions of tiny frustums not provide a great deal more force than one large frustum?
Hey fellas, long time lurker, first time poster here.One thing one knows for sure is that the smaller the frustum, the higher the natural frequency, so in order to excite a given mode shape, one would have to use higher excitation frequencies for smaller frustrums.
I'm not even going to pretend to understand half the maths that have been tossed around in this thread. I'm in complete awe of the work you guys have been doing to solve this mystery. I do have a question though, and forgive me for my ignorance.
Does anyone know if this effect scales with the size of the frustum? Could the frequency of the microwaves be adjusted to allow the same level of force in a microscopic frustum that is shown Nasa's macroscopic frustum? If this is the case, would a sequence of many millions of tiny frustums not provide a great deal more force than one large frustum?
...........
@Frobnicat's conjecture is based on the shifting of the center of mass due to thermal expansion.
Not only Chloroprene-Rubber (CR) has a higher coefficient of thermal expansion than High-Density-Polyethylene-HDPE, but Chloroprene-Rubber (CR) also has a higher density than High-Density-Polyethylene-HDPE.
So this further nullifies @Frobnicat's conjecture.
According to @frobnicat's conjecture, the denser, higher-thermal-expansion material ("Neoprene®") should have produced a higher measured "thrust", but NASA Eagleworks results show the opposite: the denser, higher-thermal expansion material ("Neoprene®") resulted in insignificant thrust.
...
Hey fellas, long time lurker, first time poster here.One thing one knows for sure is that the smaller the frustum, the higher the natural frequency, so in order to excite a given mode shape, one would have to use higher excitation frequencies for smaller frustrums.
I'm not even going to pretend to understand half the maths that have been tossed around in this thread. I'm in complete awe of the work you guys have been doing to solve this mystery. I do have a question though, and forgive me for my ignorance.
Does anyone know if this effect scales with the size of the frustum? Could the frequency of the microwaves be adjusted to allow the same level of force in a microscopic frustum that is shown Nasa's macroscopic frustum? If this is the case, would a sequence of many millions of tiny frustums not provide a great deal more force than one large frustum?
@Notsosureofit has disclosed in this forum's thread his plans to test a smaller cavity with a higher excitation frequency, and his plan to use a Gunn diode (http://en.wikipedia.org/wiki/Gunn_diode) to generate the microwaves inside the cavity.
Concerning the use of literally "millions" of these devices (as in an Integrated Circuit), this could no longer involve microwaves (if possible at all) but it would mean much higher frequencies, because the wavelengths get cut-off due to the size of the cavity hence a much smaller cavity implies that the lowest natural frequency must be much higher.
....We had a discussion with reference to a drawing presented by Paul March showing thermal expansion of the dielectric.
My conjecture is not about dielectric disc's CoM shift playing an important role in the thrust (did I say that ? Where ?) ...
http://web.ornl.gov/~webworks/cppr/y2001/pres/111404.pdf)).
http://web.ornl.gov/~webworks/cppr/y2001/pres/111404.pdf)).
The subject of thermal "pumping" is one that will have to be carefully considered in any Cavandish experiment. What procedures are best for it's elimination ? Making sure the CG of the heated object doesn't move ?
@Rodal,:)
Yes, that was about recoil forces, my arguments are still valid, a block of material starting to expand thermally will push a wall against which it is resting, whether the expanding material is the hot gas of an explosion or a block of PTFE heating from the left against copper at 0.1°C/s, it's only a (huge) difference of magnitude, not of nature (as far as recoil is concerned). Done some number, such recoil is not significant given inertia of pendulum. Like 0.1µN on the 1st second of heating. Kind of, order of magnitude. Please call it 0 if you feel so inclined. But I will continue to stand on my position on italic statement (separate post later to avoid mixing).
....
Nope. (and I dare say, we are yet to see the charts recording those "insignificant thrusts" with or without such or such dielectric thereof, but this is an aside)
My conjecture is not about dielectric disc's CoM shift playing an important role in the thrust (did I say that ? Where ?) My conjecture is about some test article part's CoM shifting to the left (toward the small end) relative to fixation on the arm. Now what is susceptible to move to the left ? You know that better than anyone, you "invented" the inward buckling of the big end cap. The part that is the most heavily heated (granted this is not by a blowtorch !) and that has a boundary constraint such that, in first approximation, there is a square root between the delta expansion in plane and the resulting displacement perpendicular to plane : buckling is a very efficient amplifier. Under such buckling or near buckling conditions, the mass*displacement of the big end cap would play the major part of test article CoM's shift. Quantitative estimates ongoing...
The problem with thermal explanations is that, in particular in vacuum, given the low temperature deltas (a few °C) the evacuated heat rates are quite low relative to the received powers. The time constants to thermal equilibrium appear way beyond the 45s of a whole run. Therefore the fact that on some "thrusts" rises we see what looks like a thermal first order constant rate heat charge against a proportional loss don't hold water. At 45s the various parts are still swallowing heat at constant rate and evacuating near to none, we would have a near linear rise in temperature wrt time all way through. So if LDS delta is proportional to Com shift (as per the tilted pendulum component), Com shift proportional to expansion, expansion proportional to temperature, and temperature proportional to time, we should see a linear rise, and not a "step". Yes but the buckling could make Com shift proportional to square root of expansion. Now look at the chart below and see the step not as a cst-cst*exp(-cst*t) as per a naive thermal explanation but as a cst*sqrt(cst*t).
So the "attack" and the "sustain" can both be very well explained by progressive thermal expansion near buckling conditions and by a slightly tilted Z axis. Now for the fall (decay) : for those still believing that thermal explanations are irrelevant, how is it possible that the decay is lingering at high LDS values for so long after power off ? But, with so low thermal radiation for cooling, there is no reason (from my conjectures so far) that there would be any significant decay at all : from my hypothesis the signal should stay constantly high at power off, only starting falling at a very small rate (much smaller that the rise rate).
This is why I said in previous post to Star-Drive that I don't believe in thermal effect as being the only cause of observed signal, from the shapes. Not because of rise and sustain (square root buckling amplification + tilted Z allowing for sustained "thrusts" by sustained relative Com's displacements) but because of decay. I do have an idea to explain that : Rodal have you considered that the supporting copper ring around the FR4 big end cap would also expand thermally ? What would happen if there was a (thermal conduction driven) temperature "delay" between the cap and the ring so that when the power stops the difference between cap temperature and ring temperature falls fast enough to be compatible with the time constant of the observed decay ? This is my leading conjecture. I now do believe again in the possibility of a purely thermal explanation wholly consistent with both magnitude and shape of signal.
Given 1) the extremely small funding (by any objective assessment) of the NASA Eagleworks project, 2) the small magnitude of the measurements involved, 3) the outstanding claims (including issues of conservation of momentum), and 4) the barely 6 months since the release of the "Anomalous..." report and the discussion in this thread, I don't find it at all "amazing" that there is no uniformly accepted mechanism for the measurements. Actually I don't understand what "acceptance" could possibly mean in this context (an anonymous Internet forum thread).
....
It's amazing how long this discussion has gone on. ....yet there is still not an accepted explanation for the anomalous thrust... There are several observations that can't be disputed:
....
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena."Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
Actually, an objective, fair assessment starts by acknowledging that progress has been made in eliminating proposed explanations for the thrust measurement being an experimental artifact. For example:
....
It's amazing how long this discussion has gone on. ....
There are several observations that can't be disputed:
There are several observations that can't be disputed:
1) The thrust signature for both the Cannae device and the Eagleworks cone shaped cavity are similar to the thrust signature of the capacitor calibrator. All are underdamped and have nearly the same natural frequency. This is to be expected because all are step responses. However this is only true for thrust waveforms from the AIAA Aug 2014 paper.
2) The correction for error thrust due to PA current interacting with the damping magnets is not done for the vacuum tests. It appears this error source was eliminated.
3) The thrust signature for the vacuum tests are very different. There is no overshoot or ringing, the rise time is slow, and a residual thrust remains after the RF is turned off. This test, if it was to confirm earlier results, would have to have the same thrust signature (overdamped). Instead it looks like a thermal effect. The displacement is very small (from 1 - 4 micrometers).
One possible explanation is that the PA current went up when the dielectric material was put in the cavity, due to a higher SWR. If the PA current was above the level that was used to measure the correction factor then the anomalous thrust seen was just more magnetic torque. Since this correction was not used with the vacuum tests it can be assumed the problem was mitigated - maybe by coaxializing the power leads. Frobnicat has proposed an explanation for the residual force seen in the vacuum measurements. With no air surrounding the cavity it takes much longer for the heat to escape. Some kind of long duration thermal flexing is causing a change in the LDS reading. It may be because the alignment of the beam changes ever so slightly when the CM changes.
The indisputable fact that the two sets of experiments show a thrust waveform with very different shape even though the TP has not been changed invalidates the claims.
Observation #1) The explanation (e.g. @frobnicat's jet model, and by several blogs in the Internet) that the thrust measurements were due to thermal convection in the air has been nullified by NASA Eagleworks tests in a hard vacuum at 6.6*10^(-9) standard atmosphere = 0.0000000066 standard atmosphere
While the vacuum test did invalidate the theory of anomalous thrust being the result of air currents it also invalidated the anomalous thrust. The earlier STP tests and the vacuum test were done with the same hardware and had the same driving function. The system response should be similar but they aren't. There are two different causes for the indication of an anomalous thrust. Therefore there is no anomalous thrust.
Actually, an objective, fair assessment starts by acknowledging that progress has been made in eliminating proposed explanations for the thrust measurement being an experimental artifact. For example:
....
It's amazing how long this discussion has gone on. ....
There are several observations that can't be disputed:
....
Observation #1) The explanation (e.g. @frobnicat's jet model, and by several blogs in the Internet) that the thrust measurements were due to thermal convection in the air has been nullified by NASA Eagleworks tests in a hard vacuum at 6.6*10^(-9) standard atmosphere = 0.0000000066 standard atmosphere
...
Karl Popper: The Logic of Scientific Discovery (1934).
There is always some uncertainty associated with scientific conclusions; physical sciences never absolutely prove anything (unlike Mathematics). What physical sciences do is nullify false explanations.
John von NeumannQuoteThe sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena."Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
While the vacuum test did invalidate the theory of anomalous thrust being the result of air currents it also invalidated the anomalous thrust. The earlier STP tests and the vacuum test were done with the same hardware and had the same driving function. The system response should be similar but they aren't. There are two different causes for the indication of an anomalous thrust. Therefore there is no anomalous thrust.
Observation #1) The explanation (e.g. the jet model from a poster in this thread, and alternative air current conjectures in several blogs in the Internet) that the thrust measurements were due to thermal convection in the air has been nullified by NASA Eagleworks tests in a vacuum at 6.6*10^(-9) standard atmosphere = 0.0000000066 standard atmosphereIf some kind of perfect Ion engine expels a gas with a density as thin as the one in the NASA Eagleworks vacuum chamber, through a one cm3 nozzle and at a relativistic speed (let say 200,000 km/sec) the thrust due to this very thin gas is in the order of several Newtons.
Welcome to the discussion
I'm probably misunderstanding you, but in the following post, Paul March says:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1329225#msg1329225
"As to why the vacuum test were observing less thrust than in air tests. please note the difference in the RF amps there were driving each test series. The 30W Mini-Circuit Class-A RF amp was used for the in-air series reported in the 2014 JPC paper, whereas a 100W EMPower Class-A/B RF amplifier was used in the vacuum tests to date. "
....
2) Accepting that 2 different experiments have produced results that contradict each other.
....
Occam's razor states that among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.
Does anyone know if this effect scales with the size of the frustum? Could the frequency of the microwaves be adjusted to allow the same level of force in a microscopic frustum that is shown Nasa's macroscopic frustum? If this is the case, would a sequence of many millions of tiny frustums not provide a great deal more force than one large frustum?
Does anyone know if this effect scales with the size of the frustum? Could the frequency of the microwaves be adjusted to allow the same level of force in a microscopic frustum that is shown Nasa's macroscopic frustum? If this is the case, would a sequence of many millions of tiny frustums not provide a great deal more force than one large frustum?
Submillimeter-wide multiple terahertz radiation cavities covering the entire structure of the ship, actually being the ship, without any thruster visible. What an interesting and provoking thought!
What these satellites lack is a viable propulsion system, says MIT aeronautics and astronautics alumna Natalya Brikner PhD ’15, co-founder and CEO of Accion Systems. “You can make a satellite the size of a softball with a surprising amount of capabilities, but it can’t maneuver properly and falls from orbit quickly,” she says. “People are waiting for a solution.”
Now Accion has developed a commercial electrospray propulsion system — their first is about the size of a pack of gum — made of tiny chips that provide thrust for small satellites. Among other advantages, Accion’s module can be manufactured for significantly less than today’s alternatives.
This technology could enable low-cost satellites, such as those known as “CubeSats,” to become more viable for various commercial and research applications, including advanced imaging and communications, where numerous satellites could provide global coverage. “That requires propulsion, but something so small that it won’t interfere with the small volume and resources a small satellite already has,” says Accion technical advisor Paulo Lozano, an associate professor of aeronautics and astronautics who invented the underlying technology.
....
Occam's razor states that among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected. The vacuum tests do not show the underdamped response that was seen earlier. Something was done to mitigate the thrust error caused by the amplifier current generating a torque against the damping magnets. The picture below shows a large attenuator on what looks like the output of the amp. This was used possibly to minimize the affects of high SWR. A high SWR results in the amplifier drawing excessive current. Earlier posts describe this problem and that the amp had to be returned for repairs. Something was done to mitigate the thrust error from amplifier current in the vacuum tests. This attenuator may have been installed for that reason. With 2 different step responses we are left with the choice of:
1) Elaborating on the theory of this device further to explain why the system response changes.
2) Accepting that 2 different experiments have produced results that contradict each other.
Of these two choices Occam requires we choose the one with the fewest new assumptions, which is #2.....
Occam's razor states that among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.
1) As per above, the experiments are not exactly the same: besides testing in a relative vacuum (6.6*10^(-9) standard atmosphere) vs. one standard atmosphere, there are a number of components that have changed (for example, besides " The 30W Mini-Circuit Class-A RF amp was used for the in-air series reported in the 2014 JPC paper, whereas a 100W EMPower Class-A/B RF amplifier was used in the vacuum tests to date" you yourself point out the following change: " Something was done to mitigate the thrust error caused by the amplifier current generating a torque against the damping magnets.
2) As used in classical logic: "a contradiction consists of a logical incompatibility between two or more propositions. It occurs when the propositions, taken together, yield two conclusions which form the logical,
3) When applying Occam's razor, the focus should be on simplicity overall,
An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
....
Occam's razor states that among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected. The vacuum tests do not show the underdamped response that was seen earlier. Something was done to mitigate the thrust error caused by the amplifier current generating a torque against the damping magnets. The picture below shows a large attenuator on what looks like the output of the amp. This was used possibly to minimize the affects of high SWR. A high SWR results in the amplifier drawing excessive current. Earlier posts describe this problem and that the amp had to be returned for repairs. Something was done to mitigate the thrust error from amplifier current in the vacuum tests. This attenuator may have been installed for that reason. With 2 different step responses we are left with the choice of:
1) Elaborating on the theory of this device further to explain why the system response changes.
2) Accepting that 2 different experiments have produced results that contradict each other.
Of these two choices Occam requires we choose the one with the fewest new assumptions, which is #2.....
Occam's razor states that among competing hypotheses that predict equally well, the one with the fewest assumptions should be selected.
1) As per above, the experiments are not exactly the same: besides testing in a relative vacuum (6.6*10^(-9) standard atmosphere) vs. one standard atmosphere, there are a number of components that have changed (for example, besides " The 30W Mini-Circuit Class-A RF amp was used for the in-air series reported in the 2014 JPC paper, whereas a 100W EMPower Class-A/B RF amplifier was used in the vacuum tests to date" you yourself point out the following change: " Something was done to mitigate the thrust error caused by the amplifier current generating a torque against the damping magnets.
2) As used in classical logic: "a contradiction consists of a logical incompatibility between two or more propositions. It occurs when the propositions, taken together, yield two conclusions which form the logical,
3) When applying Occam's razor, the focus should be on simplicity overall,
If the Eagleworks device was actually producing a thrust the STP and vacuum test would have been very similar. The reason for doing a vacuum test was to show the device worked the same in a vacuum and that the results were not because of air currents, etc. This concept of achieving consistent results is common to many activities. If for example you had two FFT programs and they gave you different results for the same input where would you be? So this is an important concept for theoreticians. People who get their hands dirty doing experiments, writing software, or designing hardware have the same goal of achieving consistent results. Without it you have no benchmark to measure success.
Using a different RF amp and adding an attenuator would not change the basic nature of the test. They are applying an RF pulse of predetermined frequency and power level to the cavity. What determines the step response of the system is the TP, what it is loaded with, and what kind of damping it has.
The Aug. 2014 AIAA paper presented several thrust waveforms as evidence of an anomalous thrust. Taking the Eagleworks team at their word we have examined these thrust waveforms and noted they have an overshoot, ringing, and an undershoot. This is entirely a function of the TP, its damping, etc. The same response is seen with the capacitor calibrator and a similar response is seen with the Cannae drive. Earlier an error thrust waveform was also shown. This error waveform was acquired when the dummy load was used. Further tests subtracted this error waveform. It also had the same overshoot, ringing, and undershoot (underdamped) as all the other waveforms.
The thrust waveforms from the vacuum test are not underdamped like the earlier thrust waveforms. However the calibration waveform in the same picture does have an underdamped response. It appears to me that by mitigating the error thrust in some way the underdamped characteristics have been removed from the thrust waveform. From this I conclude the earlier thrust waveforms were actually error waveforms that were not corrected for because the amplifier current was higher during the test runs than it was when the correction factor was acquired (the dummy load test). This is a logical inference which I understand some people may not want to accept. But the fact remains the two set of experiments have produced inconsistent results.
The vacuum tests resulted in very different waveforms. Thrust continues the after RF is off. This is very unusual. How is momentum stored in the cavity? The earlier tests didn't show this.
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
... have very different thermal torque pendulum responses than the TM212 (your TM221 I think) cases we've discussed of late. That fact might be of importance when discussing whether these thrust signals are real or just artifacts......Thanks Paul. Great reply with quantitative, factual, objective, helpful information. :)
Okay I'm going to use E field drive and sense probes (instead of loops) within the cavity placed at 1.36" from the large plate.
It seems to me that the connector should be at the small end. I'm kind of torn on this. It probably doesn't matter. Shawyer/Eagleworks have the connectors at the large end, so I will too.
There is a nifty calculator here to make it easy:
http://www.turnpoint.net/wireless/cantennahowto.html
http://www.lincomatic.com/wireless/homebrewant.html (more info)
Also some backgrounders for those who are interested:
http://www.radartutorial.eu/03.linetheory/tl11.en.html
http://www.maritime.org/doc/neets/mod11.pdf
This is also in agreement with the 15% of 9" cavity height from the large end which came out to 1.35", brought up here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1331854#msg1331854
The length of the probe will be 1.21" or 31mm, based on a 1/4 wavelength of the desired frequency 2450mhz.
The type of connector will be an N-type female in the top picture, as opposed the one in the bottom picture. That way I only have to drill one hole instead of five per connector. The size of the center hole required for both is within 1/16" so I'm not going to bother with the 4 hole bulkhead connectors I got. I wanted to see them both before I decided on which one to use.
The connectors were purchased from here, I guess they sold out because they now say unavailable:
http://www.amazon.com/gp/product/B00OOF54QW/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
http://www.amazon.com/gp/product/B006Z95L8Q/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I'm sure there are more on Amazon, but if not, I've purchased from these guys before and had a good experience:
http://www.fab-corp.com/home.php?cat=274
Rodal I need your expertise ;D
On the magnetic field maps given by Eagleworks simulations and from your exact solutions, is it correct to interpret that the heating power per unit area of frustum inner wall will depend locally as the square of the magnetic field magnitude ? Is the scalar intensity value map below enough to get the heating rate at each point or is the vector map required ? Will we have a smooth transition (in heating rate per unit area) between the PCB plate and cone in spite of the angle they make at the rim ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635195;image)
Trying to get a more accurate view on displacements : the PCB plate can buckle by thermal expansion against a rigid rim, but the rim is itself heating and expanding, will try an axisymmetric simulation taking both into account + thermal gradient (across thickness) induced "warp".
Rodal I need your expertise ;D
...
1) Paul March kindly supplied both the COMSOL Finite Element dissipated heat (W/m^2) per unit area (the finite element model takes into account geometrical changes like the "angle" you are concerned with) as well as the NASA Eagleworks thermal IR camera measurements:
...
so you don't need to rely solely on the magnetic field
2) Assuming an adiabatic process, the volumetric power dissipation Pdissipated in the material due to the applied magnetic field should be:
Pdissipated = Pi*f*Chi"*(B^2)/(mu*mur) = Pi*f*Chi"*(H^2)*muo
f=frequency (Hz)
Chi"= out-of-phase susceptibility (complex component of the susceptibility) of the material
mur = relative permeability of the material
B = magnitude of induction = permeability * H
H = magnitude of magnetic field strength
So yes, assuming an adiabatic process, the volumetric power dissipation goes like the square of the magnitude of the magnetic field.
3) The magnitude of the total vector resultant matters (one needs to take into account the resultant of the vector components, which has been done in the plot supplied by Paul March). The direction doesn't matter.
4) Questions like "Will we have a smooth transition (in heating rate per unit area) between the PCB plate and cone in spite of the angle they make at the rim ?" and other statements in this and the other posts I can't follow without seeing the unstated equations, assumptions and values, you use for your models. For example, I don't understand why you are concerned by "a smooth transition" due to the geometrical angle when we have discontinuous material properties between the epoxy and the copper) :)
....Speaking personally, it would be clearer if you would state the equations that you are using for your posted calculations, defining the variables in the equations, and the values of the parameters you used to arrive at a solution. (e.g. what were the material property inputs you used and the equations you used for the personal code thermal calculations?)
For the rest I don't see how I could make the statements more clear (more synthetic yes probably)...
Yes, this is a very informative instantaneous map of temperature, but I wanted to reconstruct the dynamic (transients) and also have the gradients through thickness.....Paul March gave us several plots, including:
....EDIT (hat tip to @frobnicat):
Why I wanted to start again from the primary heat flux dissipated within the skin depth copper side, even if it is with far lower numerical tools than provided by Comsol results. I wish Eagleworks had added a deformation study from the very accurate thermal maps.
... I'm still struggling to assert, especially if the PCB as even a very modest inward warp to start with (which is a concern for single sided boards) like a few 10s of microns at belly.Since the bending deformation of the end plate (due to a thermal gradient through its thickness, referred to as "oil canning" in the picture below) is inwards, and you had arrived at the conclusion that such an inward deformation produces a force that is in the opposite direction to the measured force , why are you so interested in performing this calculation?
...
....Speaking personally, it would be clearer if you would state the equations that you are using for your posted calculations, defining the variables in the equations, and the values of the parameters you used to arrive at a solution. (e.g. what were the material property inputs you used and the equations you used for the personal code thermal calculations?)
For the rest I don't see how I could make the statements more clear (more synthetic yes probably)...
The fact is that Paul March gave us the calculated dissipated power W/m^2 vs. location. In your prior post you referred to Paul's data for the calculated magnetic field, and in this post you acknowledge the measured temperature.....To be precise, Eagleworks did not provide COMSOL calculations (to my knowledge) of a thermal map (temperature vs. location). What Eagleworks provided are (COMSOL Finite Element) calculations for the dissipated power per unit area (in units of power per surface area: Watt/m^2) surface losses throughout the whole 3-Dimensional surface (both the large and small diameter ends as well as the lateral round conical surface). And it is the volumetric power dissipation that goes like the square of the magnitude of the magnetic field, which was your question. So, Paul March had already given you the elements to answer your question: both the magnetic field and the power dissipation density.
Why I wanted to start again from the primary heat flux dissipated within the skin depth copper side, even if it is with far lower numerical tools than provided by Comsol results. I wish Eagleworks had added a deformation study from the very accurate thermal maps.
The thermal map is a result of IR thermal measurements.
... I'm still struggling to assert, especially if the PCB as even a very modest inward warp to start with (which is a concern for single sided boards) like a few 10s of microns at belly.Since the bending deformation of the end plate (due to a thermal gradient through its thickness, referred to as "oil canning" in the picture below) is inwards, and you had arrived at the conclusion that such an inward deformation produces a force that is in the opposite direction to the measured force , why are you so interested in performing this calculation?
...
If your purpose is to show that the actual EM Drive force (due to the Quantum Vacuum or whatever else may make it work in space?) is larger than the measured force, then I lost track of the discussion somewhere because I recall you stating that you wanted to show the opposite: that the measured force was an artifact.
?
....
For the later results (thermal conduction), I'm not expecting anyone give too much credit in the accuracy of a personal simulation code,....
FR4
density 1850 kg/m^3
specHeat 600 J/kg/K
...
....
For the later results (thermal conduction), I'm not expecting anyone give too much credit in the accuracy of a personal simulation code,....
FR4
density 1850 kg/m^3
specHeat 600 J/kg/K
...
It is not a question of giving personal credit, but my understanding of your posting such calculations is to check whether the experimental results are an artifact or whether they are due to a real thrust that can work for outer space propulsion. If you don't post the equations and the material properties you use, then how can the reader ascertain how to evaluate what you post?
To give one example, we see now that you used a value of 600 J/kg/K for the specific heat of FR-4 (no reference as to where this came from). However, Rebecka Domeij B¨ackryd at LINK¨OPING University (Sweden) used a value twice as high: 1200 J/kg/K (see page 14 of http://www.diva-portal.org/smash/get/diva2:18631/FULLTEXT01.pdf )
....I just stated that I personally have a hard time following your train of thought, and that I personally would prefer to see more equations. You could justifiably answer that it is my fault because of my lack of reading comprehension. I don't recall me stating that it was your fault, I actually recognized that it is probably my fault because in physics and technical science I can much better understand equations than words, particularly about things like forces (I surely don't understand Roger Shawyer's discussion of forces in the EM Drive either).
You complain that my hypothesis and variables and equations are not clearly put, but do you read me seriously ?...
A movement to the left of a part of mass M will make a force to the right as recoil : F(t)=-M d²CoMPosition(t)/dt². " OK, so the force is to the right and it is opposite to the measured force
..."Such F(t) is small, very small, even by µN standards. It depends on the second derivative of the shift (wrt time).
Now, if we have the right to go past those negligible recoil effects :
... A slow inward deformation don't produces a force (ah ah, it does, but is too small to be significant). I'm no longer talking of force. I'm talking change of rest equilibrium position (by rest equilibrium I mean : the stable position when there is no force)
....I just stated that I personally have a hard time following your train of thought, and that I personally would prefer to see more equations. You could justifiably answer that it is my fault because of my lack of reading comprehension. I don't recall me stating that it was your fault, I actually recognized that it is probably my fault because in physics and technical science I can much better understand equations than words.
You complain that my hypothesis and variables and equations are not clearly put, but do you read me seriously ?...
....Sorry again for not recalling your prior posts and needing a brief summary.
I wanted to show that the measured "force" (LDS reading really) might not be a force at all, but a change in equilibrium rest position, as per the diagram showing how the equilibrium rest position is different depending on test article CoM position...
Ok, despite my best efforts (which, admittedly are rather feeble), I can no longer tell what 'frobnicat' is attempting to accomplish. Is he arguing that all of the 'thrust' produced by this device is some sort of thermal artefact? From what I can tell, the goalposts seem to have moved at least once.
Executive summary time, please.
Er, yes, no, this is in progress but would need a simulation with professional level tools I haven't knowledge of to be assessed with any certainty. Needs both buckling and thickness gradient flexing deformations, with asymmetrical thin plate modelling (single sided PCB). Amongst others, Code Aster is a free simulation framework of more than 1000000 lines code that could do the job but require quite a training to be used correctly. Right now I'm trying to do order of magnitude estimates with small personal code ~500 lines of code. Is it in the ballpark or not ? Preliminary results say maybe.....Sorry again for not recalling your prior posts and needing a brief summary.
I wanted to show that the measured "force" (LDS reading really) might not be a force at all, but a change in equilibrium rest position, as per the diagram showing how the equilibrium rest position is different depending on test article CoM position...
QUESTION1: have you calculated the change in Center Of Mass position for these different cases? (yes or no ?)
if your answer to QUESTION1 is no, stop reading.
if your answer to QUESTION1 is yes, then,
QUESTION2: do your calculations for the change in center of mass position give a displacement that is close to the displacement vs. time measurements at NASA Eagleworks?
Did you calculate the thrust that your "thought-experiment ion-engine" would produce with "air propellant expelled through a 1 cm^3 nozzle" stored at 1 standard atmosphere and heated in the microwave cavity? (the same "imperfect Ion engine" that would produce the measured thrust force of 50 microNewtons thrust with "air propellant expelled through a 1 cm^3 nozzle" stored at 0.0000000066 standard atmosphere "by accident"?)Observation #1) The explanation (e.g. the jet model from a poster in this thread, and alternative air current conjectures in several blogs in the Internet) that the thrust measurements were due to thermal convection in the air has been nullified by NASA Eagleworks tests in a vacuum at 6.6*10^(-9) standard atmosphere = 0.0000000066 standard atmosphereIf some kind of perfect Ion engine expels a gas with a density as thin as the one in the NASA Eagleworks vacuum chamber, through a one cm3 nozzle and at a relativistic speed (let say 200,000 km/sec) the thrust due to this very thin gas is in the order of several Newtons.
A far more imperfect Ion engine can certainly provide 100,000 less thrust by accident at this level of pseudo-vacuum.
...Suppose (for argument's sake) that your conjecture for shifting center of mass due to thermal expansion could explain the measured response in one direction, which will call the "forward" direction.
Er, yes, no, this is in progress but would need a simulation with professional level tools I haven't knowledge of to be assessed with any certainty...It could.
At least it needs to be properly assessed before it can be ruled out. ...
...
Suppose (for argument's sake) that your conjecture for shifting center of mass due to thermal expansion could explain the measured response in one direction, which will call the "forward" direction.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=811960;image)
Then, how could it possibly explain the measured response in the opposite direction, with the experimenters able to put the EM Drive into "reverse" at will?
... a picture of the new heat shields for our torque pendulum's upper and lower torsion springs, (more belts and suspenders to mitigate thermal drifts in the TP baseline), the reversed test setup drawing and the best reversed thrust plot obtained just before or during when our second and last 120W max RF amplifier was dying from internal corona discharges around its RF output circulator.
1) Do you agree that the only serious data we have about "reverse" is in fact just a 180° turn of test article ?
2) That a 180° turn of the test article will reverse a thermal effect as much as it reverses a thrust ?
..we don't have precise data concerning a situation where some sustained level of apparent thrust would be toward the big end of test article ? I do recall some mention by Paul March to such thrust toward big end was made, would appreciate if you or anyone find that.
I do agree that precise and consistent data on point 4 [Reverse tests data] would indeed nullify a lot of my conjectures.
FYI
http://scitechdaily.com/researchers-hope-to-provide-new-insights-into-quantum-gravity/
But, it's a spherical cavity.......
...
1) Please refer to the image I provided: of a car's shift mechanism, showing a REVERSE shift. I certainly do NOT consider turning the EM Drive around by 180 degrees to equate "running in reverse", any more than turning a car engaged in "D" (or in 1st shift) around by 180 degrees would make it run in reverse: the car would still run FORWARD (but in the opposite direction).
Reverse, as indicated by the graph I provided refers to going backwards: a car's reverse ! That's why I attached the huge image showing a car's reverse shift (the significance of the "reverse" R cannot be misconstrued )
2) Of course, "That a 180° turn of the test article willreverseturn a thermal effect as much as itreversesturns a thrust ?"
So what ?
...
Your post above questions whether the EM Drive can be run in reverse. You state:Quote from: @frobnicat..we don't have precise data concerning a situation where some sustained level of apparent thrust would be toward the big end of test article ? I do recall some mention by Paul March to such thrust toward big end was made, would appreciate if you or anyone find that.
@Mulletron [hat tip for being the first one in the thread to use the car's reverse shift image] has a number of posts also interpreting that the EM Drive had been run in reverse, for example certain modes run the EM Drive forward and certain modes run the EM Drive in reverse. One can, in principle, then run the EM Drive in reverse, at will, by "turning the (virtual) knob" of the exciting frequency such as to excite a natural frequency that has a mode shape such as producing an EM Drive's thrust in reverse
I will let Paul March:
1) describe how else the EM Drive can be run in reverse at will [using the literal definition of "reverse"].
2) determine whether my interpretation of the "reverse" measurement of -9.9 microNewtons is indeed a reverse thrust measurement (my interpretation was based on a literal interpretation of the word "reverse") or whether it is a measurement with the EM Drive turned around by 180 degrees (your interpretation). The image for "reverse" shows the same frequency as for the "forward" images, so if the frequency is correct it means that it was run in the same mode shape both forward and backwards. Either A) you are correct that the image is really not an EM Drive in reverse (but instead it is the EM Drive turned around and still running forward), or B) if it is indeed running in reverse it must have been accomplished by some other means, other than by changing frequency.
3) if my interpretation of the image showing "reverse" measurement of -9.9 microNewtons was NOT a reverse thrust measurement, but instead was forward thrust with the EM Drive turned around 180 degrees, then could Paul March please point out to where is the data for the EM Drive run in Reverse.
PS: No need to warn about "absurd controversies" or about "indulging ourselves." Such warning (and your discussion about turning the EM Drive around by 180 degrees) was unnecessary if you take into account 1) the definition of the word reverse, and 2) the image I provided of the car's shift mechanism showing a Reverse shift. The meaning of "R" reverse in a car cannot be misconstrued.
No need for us to get upset about this. It is important to settle this issue, as you recognize:Quote from: @frobnicatI do agree that precise and consistent data on point 4 [Reverse tests data]
would indeed nullify a lot of my conjectures.
The thrust waveforms have changed significantly in the past few months. The first picture below is from April 2014. 19.9 Watts of RF power resulted in a peak thrust of 105 microNewtons. There is no mention what the error thrust due to magnetic interaction is however. The waveform has a fast rise time and has an overshoot and other characteristics of an underdamped response. It is very similar to the calibration drive and the error thrust.
The next thrust waveform, in a vacuum, is very different. I think it is the result of a long duration thermal effect and doesn't indicate any thrust at all. With 50 Watts and a vacuum surrounding the cavity a thermal response would be expected.
The reverse test, also with 50 Watts, brings us back to the underdamped response, but at a very low level.
With no consistency in any of these data the only thing anyone knows for sure is:
1) Heat is being dissipated in the cavity.
2) DC current near a magnet generates torque.
Dr. Rodal:
Looking over some of our test results from last spring and summer just now, I realized that I had forgotten to provide this forum a few test runs at some of the other resonant modes we've looked at that used different dielectric discs and locations including polycarbonate which I hadn't mentioned before. These examples are attached and you will note that these other copper frustum resonant modes (TM010 & TE012) have very different thermal torque pendulum responses than the TM212 (your TM221 I think) cases we've discussed of late. That fact might be of importance when discussing whether these thrust signals are real or just artifacts...
PS: The magnitude of the torque pendulum's overshoot is directly related to what version of the magnetic damper that was used for the particular test in question and how thick the copper damper blade was at the time. At the moment we are using an arrangement that is slightly over-damped in an attempt to smooth out some of the pesky low frequency seismic noise in the system.
DPS: The magnitude of the RF amp's dc current induced thrust signal offset is directly related to how much leakage current is going through the torque pendulum's steel torsion bearings. As I became aware of this problem over the last year, I've found various ground wiring tricks to mitigate this dc current induced negative going offset, but I've never found a way to get rid of all of it.
Best, Paul M
I disagree that "reverse" only means to move backwards, so may I suggest that a different description such as "flipped", "turned around" or "rotated" be used to better describe the experimental setup, especially given the potential for there to be a way to change the directionality electrically (and if that is true then perhaps we could follow the circuit symbol for a cell to help us communicate such directionality i.e. thrust towards the big end is positive; small end is negative)
...
one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used
All:
Sorry I didn't make the time to participate in this ME-Drive forum for the last 6-to-8 months up, but I will try to catch up with everyone else in due course. That said lets try to answer the questions that popped up since my morning post.
1. I was not the lead author for the Eagleworks' 2014 AIAA/JPC paper and in fact I only supplied pictures and data for same during that period because Dr. White thought that my time was best spent in the lab gathering data instead of report writing. Thus some of the details that Dr. Rodal is looking for may have been lost or garbled in the report writing by the others on the author list.
2.0 The thrust vector for the four resonant modes examined in detail, (the cavity's fundamental TM010, TE012, TM211 & TM212 for our copper frustum is normally in the frustum's large OD to small OD direction for most, but not all the E&M resonant modes checked. However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map. Sorry, but a one size fits all solution to this EM-Drive thrust direction is not available in this venue because of the importance of the ExB phase relationship of the expressed Lorentz forces between the excited E&M fields and the possible dielectric and QV plasma flow phenomenon that may be at work in each resonant mode expressed. That is why this type of E&M thruster is so hard to get a handle on, for there are far too many degrees of freedom in the system to track let alone directly control.
3. The Eagleworks vacuum chamber's main body is made from 304L stainless steel while its swing out door is made from aluminum. Most of the nuts and bolts in the vacuum chamber are also made from 18-8, 304 or 316 stainless steel alloys.
Now to try to answer Dr. Rodal's specific questions:
"1) In the NASA experiments the truncated cone's center of mass moved towards the [ ? ] diameter end (where ? stands for big or small)"
For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum.
"2) In the NASA experiments, we at NASA Eagleworks define the thrust force direction to be in the [? ] direction as the movement of the truncated cone's center of mass (where ? stands for same or opposite)"
For just the TE012 & TM212 excited resonant modes, the thrust force direction AKA thrust vector was observed to be in the same direction as the movement of the frustum's center of mass when RF power was applied to the frustum's magnetic loop antenna.
If I missed a question along the way keep asking, but I'll be in and out of the house for the rest of the day, so I may not get to answer them until late this evening or tomorrow afternoon USA based CST.
Best, Paul M.
Quote from: Star-Driveone can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used
...
2.0 The thrust vector for the four resonant modes examined in detail, (the cavity's fundamental TM010, TE012, TM211 & TM212 for our copper frustum is normally in the frustum's large OD to small OD direction for most, but not all the E&M resonant modes checked. However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map. Sorry, but a one size fits all solution to this EM-Drive thrust direction is not available in this venue because of the importance of the ExB phase relationship of the expressed Lorentz forces between the excited E&M fields and the possible dielectric and QV plasma flow phenomenon that may be at work in each resonant mode expressed. That is why this type of E&M thruster is so hard to get a handle on, for there are far too many degrees of freedom in the system to track let alone directly control.
...
"1) In the NASA experiments the truncated cone's center of mass moved towards the [ ? ] diameter end (where ? stands for big or small)"
For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum.
...
I will calmly wait for the person that conducted the experiments (Paul March "Star-Drive") to confirm whether the EM Drive can indeed be run at will (by changing the exciting frequency) with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, and if so, to point out the relevant data demonstrating that fact.
Mr. Frobnicat, with all due respect, since you did not perform these experiments, you cannot write with pontificating authority to resolve this matter.
If Paul March answers that the EM Drive cannot be run with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, I will be very pleased to have learned this fact and to have corrected my misunderstanding.
On the other hand if Paul March answers that the EM Drive can indeed be run with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, by changing the exciting frequency, your conjecture (if it pretends to explain the total measurement) will be shown to have been already nullified by NASA Eagleworks. In that case, your conjecture might, at best, serve to explain a fraction of the measurement as a biasing artifact.
I understand that we need to wait for Paul March to explicitly "re-verify" the manner in which thrust reversal was achieved, but it does appear to me that he has already addressed this in the above quote from Feb 14. Quoting Mr. March: "one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end". To my admittedly untrained eye, this appears to be in agreement with Dr. Rodal's earlier statements, and in conflict with Mr. Frobnicat's contention that reversal was achieved by simply rotating the entire mechanism 180 degrees.
....Welcome to NASA SpaceFlight EM Drive Developments' thread :)
Paul's statement that "For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum." Would seem to explicitly contradict the calculated chart as to the direction for those modes.
Paul's statement that "For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum." Would seem to explicitly contradict the calculated chart as to the direction for those modes.
To me, it seems like 'frobnicat' came very close to 'reinventing the wheel' with these recent posts.
We really do need a glossary of the known points about this device.
To me, it seems like 'frobnicat' came very close to 'reinventing the wheel' with these recent posts.I started to try to do this the other day. We need everyone to pitch in and add what they can, and we really need a wiki format to update.
We really do need a glossary of the known points about this device.
Re. Hypotheses looked at - where does our lengthy discussions of dark matter fit?we had a lengthy discussion of dark matter and i didn't know about it?!
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946 (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946)
Quote from: Star-Driveone can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used
Thank you for bringing up this citation that allows to find the original mention of "true reverse" by mode switching....
2.0 The thrust vector for the four resonant modes examined in detail, (the cavity's fundamental TM010, TE012, TM211 & TM212 for our copper frustum is normally in the frustum's large OD to small OD direction for most, but not all the E&M resonant modes checked. However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map. Sorry, but a one size fits all solution to this EM-Drive thrust direction is not available in this venue because of the importance of the ExB phase relationship of the expressed Lorentz forces between the excited E&M fields and the possible dielectric and QV plasma flow phenomenon that may be at work in each resonant mode expressed. That is why this type of E&M thruster is so hard to get a handle on, for there are far too many degrees of freedom in the system to track let alone directly control.
...
...
If a clear signal toward big end was actually recorded, it seems rather strange that such experimental plot would not have been disclosed as it may confirm the theoretical blue plot, and even if wasn't confirming this formula that would still be a strong case against a lot of classical explanations for the signal.
In the above quoted post by Star-Drive it is a matter of interpretation to understand that it is explicitly stated that there was actual toward big end thrusts or not explicitly stated. My reading is that it is not explicitly stated, but the wording is ambiguous enough that the reverse reading could be argued. I hope Paul March can settle this matter in the clearest manner : yes or no was there at some point an experimentally recorded thrust toward the big end ?Quote from: RodalI will calmly wait for the person that conducted the experiments (Paul March "Star-Drive") to confirm whether the EM Drive can indeed be run at will (by changing the exciting frequency) with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, and if so, to point out the relevant data demonstrating that fact.
Mr. Frobnicat, with all due respect, since you did not perform these experiments, you cannot write with pontificating authority to resolve this matter.
I did brought to the subject a fresh and rational third party look, as you did, as many contributors here did, and I'm not the first of the thread to give the impression of thinking having decisive arguments. My style is what it is, but I'm making perfectly sensible, substantiated, articulated arguments from the available data and what Star-Drive had the courtesy to share with us. Any sceptical person with mechanical engineering background caring to dig the disclosed informations would arrive at similar questions and doubts. So while I said I a lot of time lately (regrettably, would rather hear we), this is not a matter of me.QuoteIf Paul March answers that the EM Drive cannot be run with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, I will be very pleased to have learned this fact and to have corrected my misunderstanding.
On the other hand if Paul March answers that the EM Drive can indeed be run with the thrust force directed towards the big base (instead of towards the small base) of the truncated cone, by changing the exciting frequency, your conjecture (if it pretends to explain the total measurement) will be shown to have been already nullified by NASA Eagleworks. In that case, your conjecture might, at best, serve to explain a fraction of the measurement as a biasing artifact.
Re. Hypotheses looked at - where does our lengthy discussions of dark matter fit?we had a lengthy discussion of dark matter and i didn't know about it?!
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946 (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946)
http://www.sciencedaily.com/releases/2015/03/150306091617.htm
http://phys.org/news/2015-03-mini-black-holes-lhc-parallel.html
Well, I just searched the complete advanced concepts forum and found no mention of dark matter on any EM drive developments thread, so I guess either my memory is faulty or there has been some heavy clean-up of what many consider to be "Uggy-Bogy" science. That means we won't be including it in "hypotheses discussed."
QuoteWell, I just searched the complete advanced concepts forum and found no mention of dark matter on any EM drive developments thread, so I guess either my memory is faulty or there has been some heavy clean-up of what many consider to be "Uggy-Bogy" science. That means we won't be including it in "hypotheses discussed."
That is strange. I remember bringing it up in the first thread. We had to max out the amount of 'local' dark matter to get even close to the results reported by this device. Somebody - I think it was you, Aero - proposed a sort of 'dark matter ramjet' in connection with all this, but ultimately we went in other directions. More recently, Doctor Rodal's colleague Marshal pretty much ruled out a Dark Matter Axiom solution for the EM Drive. Maybe the thread was edited? In any event, Dark Matter looks to be something we pretty much rejected months ago.
2. Classic unknown physics
i. Casimer related
ii. Evanescent wave related
iii. General Relativity
3. New Physics
i. Quantum Vacuum -Quantum plasma theory
ii. MiHsC theory
iii. Dark Matter - Nullified based on insufficient density of DM.
I would note that in order to generate thrust according to M-E theory, the dielectric really needs to act as a quarter wave mechanical/acoustic resonator. It's hard to imagine this happening by accident, but it could so act even if very imperfectly. Paul [March] is aware of all this, and has had a hand in designing the experiment, so there is a strong possibility what they're seeing is M-E thrust
......
As for the scalar-tensor theory of gravity, predictions (falsifiability) for the EmDrive have been calculated by Pr. Fernando Minotti in his peer-reviewed paper Scalar-tensor theories and asymmetric resonant cavities (http://arxiv.org/pdf/1302.5690v3.pdf).
NASA's spaceflight internal "search" capabilities for information posted in these threads is, unfortunately, practically worthless. It is not uncommon to search for terms and get no answers.Re. Hypotheses looked at - where does our lengthy discussions of dark matter fit?we had a lengthy discussion of dark matter and i didn't know about it?!
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946 (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946)
http://www.sciencedaily.com/releases/2015/03/150306091617.htm
http://phys.org/news/2015-03-mini-black-holes-lhc-parallel.html
Well, I just searched the complete advanced concepts forum and found no mention of dark matter on any EM drive developments thread, so I guess either my memory is faulty or there has been some heavy clean-up of what many consider to be "Uggy-Bogy" science. That means we won't be including it in "hypotheses discussed."
All:
Sorry I didn't make the time to participate in this ME-Drive forum for the last 6-to-8 months up, but I will try to catch up with everyone else in due course. That said lets try to answer the questions that popped up since my morning post.
1. I was not the lead author for the Eagleworks' 2014 AIAA/JPC paper and in fact I only supplied pictures and data for same during that period because Dr. White thought that my time was best spent in the lab gathering data instead of report writing. Thus some of the details that Dr. Rodal is looking for may have been lost or garbled in the report writing by the others on the author list.
2.0 The thrust vector for the four resonant modes examined in detail, (the cavity's fundamental TM010, TE012, TM211 & TM212 for our copper frustum is normally in the frustum's large OD to small OD direction for most, but not all the E&M resonant modes checked. However, one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end, see attached resonant mode map. Sorry, but a one size fits all solution to this EM-Drive thrust direction is not available in this venue because of the importance of the ExB phase relationship of the expressed Lorentz forces between the excited E&M fields and the possible dielectric and QV plasma flow phenomenon that may be at work in each resonant mode expressed. That is why this type of E&M thruster is so hard to get a handle on, for there are far too many degrees of freedom in the system to track let alone directly control.
3. The Eagleworks vacuum chamber's main body is made from 304L stainless steel while its swing out door is made from aluminum. Most of the nuts and bolts in the vacuum chamber are also made from 18-8, 304 or 316 stainless steel alloys.
Now to try to answer Dr. Rodal's specific questions:
"1) In the NASA experiments the truncated cone's center of mass moved towards the [ ? ] diameter end (where ? stands for big or small)"
For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum.
"2) In the NASA experiments, we at NASA Eagleworks define the thrust force direction to be in the [? ] direction as the movement of the truncated cone's center of mass (where ? stands for same or opposite)"
For just the TE012 & TM212 excited resonant modes, the thrust force direction AKA thrust vector was observed to be in the same direction as the movement of the frustum's center of mass when RF power was applied to the frustum's magnetic loop antenna.
If I missed a question along the way keep asking, but I'll be in and out of the house for the rest of the day, so I may not get to answer them until late this evening or tomorrow afternoon USA based CST.
Best, Paul M.
I understand that we need to wait for Paul March to explicitly "re-verify" the manner in which thrust reversal was achieved, but it does appear to me that he has already addressed this in the above quote from Feb 14. Quoting Mr. March: "one can also reverse this thrust vector for this copper frustum by just changing which excited resonant mode is used and/or mounting the dielectric discs at the large OD end of the cavity instead of the small OD end". To my admittedly untrained eye, this appears to be in agreement with Dr. Rodal's earlier statements, and in conflict with Mr. Frobnicat's contention that reversal was achieved by simply rotating the entire mechanism 180 degrees.
These 1" thick by 6.25" (actually 6 5/16" because I left them a little wide for milling) wide HDPE circles need a ride in a lathe. Trouble is, I don't have a lathe.Great idea to put the pictures in the google drive to be able to share them !
Cutting these with a jigsaw was not fun. Because the HDPE was so thick, the waste material would just bunch up around the cut in long ribbons and it was very tough to see the cut. Normally such thick material would be cut at low speed, but running the saw at full speed helped to clear out the pesky waste material so I could see better.
Rest of pics:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
Paul's statement that "For the TE012 and TM212 excited resonant modes, our copper frustum's center of mass moved toward the small OD end of the frustum when RF power was applied to the copper frustum." Would seem to explicitly contradict the calculated chart as to the direction for those modes.
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(*) @Frobnicat asked whether the direction of the electromagnetic vector should matter for heat production due to electromagnetic power dissipation. The answer is NO !, because of the 2nd Law of Thermodynamics: a reversal of the direction of the electromagnetic field cannot possibly lead to a cooling or a thermal contraction.
...Concerning the equation used in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image, the discussion should preferably be carried on the following basis:
What do you think of the formula used in the plot titled "S21 and surface integral of cavity with 1W input power" (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image) ?
....
Do you see what motivates this particular formula ?
...
There is electromagnetic pressure of course, but isn't it supposed to integrate to 0, at least in known frameworks ?
There appear to be no cross-product but a sum of e and b(h actually) fields' energy densities taken separately. Is it equivalent ?
....But this thread should really be focused on:
Anyway, factually, using Eagleworks mode nomenclature for convenience, the reported experiments of "anomalous thrust..." show both TE012 and TM211 modes in the same direction (the small end). And the blue plot says it should really reverse between TE012 and TM211. I won't go into battle as saying that it definitely - how you say that ? ah yes - imparts a death knell to this blue plot, but those initial results do weaken the theoretical statement, to put that in diplomatic terms.
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1) Experiments (like reversing at will the direction of the thrust from the small base to the big base directions) that would nullify yet another mechanism (like the one you proposed) pretending to show the EM Drive experiment as an artifact, are very important in that they advance our state of knowledge about "EM Drive Developments - related to space flight applications."
On the other hand, discrepancies in sign between a blue plot and other plots, do not rise to the same level of significance.
One explanation, for example, could be simply that one (or both) of the plots have the wrong sign. Such errors in presentation do not rise anywhere to the same level of significance.
Do you know how many plots and equations contain errata in Feynman's original QED and path integral publications?
Ultimately what matters is whether the EM Drive experiments show phenomena that can be used for spaceflight applications, and ultimately what will matter least is whether plots were mislabeled.
When finding a contradiction between plots, one should not rush to judgement to toll the bell that the experiment is an artifact: it may simply be an innocent error in labeling a plot.
2) That there may be labeling questions is shown by:
2a) What NASA Eagleworks labels as mode TM212 I have shown should be labeled TM222
2b) The mode labeled as TM211 in the "Anomalous ..." report was reported to occur at 1.9326 GHz and 1.9367
GHz, with COMSOL FEA frequency calculated at 1.947 GHz. Yet now they report mode labeled TM212 to be tested and to occur at about the same frequency range.
I calculate that the mode labeled "TM212" (which I think should be labeled TM222) -which does not appear in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image should occur at a significantly higher frequency than TM211, never at the same frequency ( "TM212" at 2.49 GHz without dielectric and "TM211" at 2.01 GHz without dielectric). These modes were analyzed and labeled (I understand) by different engineers. It is possible that they may be one and the same mode that has been mislabeled.
3)All the emphasis you place on the signs on the blue NASA Eagleworks plot and the other plots (which could be just an error in labeling the plots), yet you ignore the fact that Roger Shawyer published experimental information showing his EM Drive Demonstrator Engine showed practically the same magnitude thrust was experimentally observed to be reversed: Shawyer reports forces in opposite directions (towards the big end and towards the small end of practically the same magnitude: 214 mN/kW and 243 mN/kW) for his Demonstrator engine.
The data being ignored (showing forces in opposite directions, towards the big end and towards the small end of practically the same magnitude), what should I say :) , oh yes, defenestrates, mechanical explanations for the EM Drive measurements being a mechanical artifact.
So we have to wait for either Paul March or another report from NASA Eagleworks to clear up this issue of where is the experimental data (position vs. time) for the truncated cone exhibiting a force (and acceleration) directed towards the big end. Are some of the plots in this thread experiments exhibiting a force (and acceleration) directed towards the big end ? At what frequencies and mode shapes ? Which plots (if any) exhibited a force (and acceleration) directed towards the big end due to the placement of the dielectric in the opposite end?Quote
2) That there may be labeling questions is shown by:
2a) What NASA Eagleworks labels as mode TM212 I have shown should be labeled TM222
2b) The mode labeled as TM211 in the "Anomalous ..." report was reported to occur at 1.9326 GHz and 1.9367
GHz, with COMSOL FEA frequency calculated at 1.947 GHz. Yet now they report mode labeled TM212 to be tested and to occur at about the same frequency range.
I calculate that the mode labeled "TM212" (which I think should be labeled TM222) -which does not appear in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image should occur at a significantly higher frequency than TM211, never at the same frequency ( "TM212" at 2.49 GHz without dielectric and "TM211" at 2.01 GHz without dielectric). These modes were analyzed and labeled (I understand) by different engineers. It is possible that they may be one and the same mode that has been mislabeled.
Yes, all right, sounds possible. So ?...
Thank for later part of previous answer. It does answer clearly to some aspects of my innocent questions, for the other aspects I'll have to learn German....No need to learn German. I included the English translation links (by the way, these are excellent translations), which I copy again here:
Thank for later part of previous answer. It does answer clearly to some aspects of my innocent questions, for the other aspects I'll have to learn German. Thank for editing the beginning. Unfortunately the tone is becoming a bit harsh so it becomes difficult to talk casually about just, you know, "what you think of ... patati patata", without resorting to lawyers....Thanks for the (yes, strong, but very) illuminating exchange. I learned many aspects of the Eagleworks experiments that I had not realized before you brought them up to our attention, and I better understand your viewpoint. Thanks for your patience and for taking your time to explain this :)
Wikipedia has a pretty good article on Maxwell's stress tensor, see: http://en.wikipedia.org/wiki/Maxwell_stress_tensor.......
What do you think of the formula used in the plot titled "S21 and surface integral of cavity with 1W input power" (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image) ?
....
Do you see what motivates this particular formula ?
...
While waiting for Paul March (@Star-Drive) to explain the background, context and significance of the equation, the following is apparent:
The terms in the http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=778912;image equation coincide with the Kronecker's delta (the unit dyadic) negative terms of Maxwell's stress tensor ("times the normal component in the z direction"). The remaining dyadic terms of Maxwell's stress tensor component are missing from this expression.
....
Sounds to me kind of like:
"Surface integral (numeric) of this expression:.....This is the integral of the sum of the magnetic and electric field surface energy densities multiplied by the z component of the vector normal to the truncated cone surface at that point"
The vector normal to the truncated cone surface does not change for different modes.
That's what it sounds like anyway.................
Sounds to me kind of like:
"Surface integral (numeric) of this expression:.....This is the integral of the sum of the magnetic and electric field surface energy densities multiplied by the z component of the vector normal to the truncated cone surface at that point"
The vector normal to the truncated cone surface does not change for different modes.
That's what it sounds like anyway.................
I agree, you are correct that it has the units of a force.Sounds to me kind of like:
"Surface integral (numeric) of this expression:.....This is the integral of the sum of the magnetic and electric field surface energy densities multiplied by the z component of the vector normal to the truncated cone surface at that point"
The vector normal to the truncated cone surface does not change for different modes.
That's what it sounds like anyway.................
If "sum of the magnetic and electric field surface energy densities" (a scalar) is replaced by "pressure" (as scalar pressure in ideal gas at thermal equilibrium) then the formula would read as the surface integral of the pressure multiplied by the z component of the vector normal to the truncated cone surface at that point. Pressure is N/m² scalar, integrated over a surface yields N. The normal_z factor (dimensionless) leaves only the z component of the force at each point. Over a patch of surface the integral result would be the z component of the force exerted by such gas on that patch. For the inner surface of a closed cavity filled by a gas at thermal equilibrium and at rest (and without pressure gradient due to gravity or acceleration), that should integrate to 0.
If this analogy holds, the units of "the sum of the magnetic and electric field surface energy densities" should be like a pressure, or equivalently energy volumetric density, in N/m² or equivalently J/m^3 (passing by Nm/m^3 and Nm is J).
Maybe this is more clear to understand "volumetric energy densities (in J/m^3) taken at the surface" rather than "surface energy densities" as the later seems to imply surface densities (in J/m²).
1) Integrating J/m^3 over a surface gives N (m²*J/m^3 -> J/m -> Nm/m -> N)
2) Integrating J/m^2 over a surface gives J, equivalent to Nm, not to N
Only 1) makes the formula dimensionally consistent (to give N in the end)
My musings, can't go much further, why I asked dr Rodal his views on the matter. Latest posts are quite readable even when lacking any decent basis with electromagnetic stress-energy tensors.
Doctor McCulloch put forth another blog post on the EM Drive, using a 'one wave' version of his theory. By and large, his predictions with this new model seem much closer to the mark than before. There are a few tests he put in red because of uncertainty over the geometry.
http://physicsfromtheedge.blogspot.com/
At times, it seems almost like this device operates in the murky area between gravity and electromagnetic radiation.
Doctor McCulloch put forth another blog post on the EM Drive, using a 'one wave' version of his theory. By and large, his predictions with this new model seem much closer to the mark than before. There are a few tests he put in red because of uncertainty over the geometry.
http://physicsfromtheedge.blogspot.com/
At times, it seems almost like this device operates in the murky area between gravity and electromagnetic radiation.
The GRT coupling between EM and Gravity is miniscule; something like billionths of a trilionth or some ridiculously small amount like that. (source: popular articles on Martin Tajmar's retracted gravity effects paper.)
Are these present effects in that slender range or are they outliers to what GRT allows? If it is it's not necessarily invalidating because GRT does not describe dark sector interactions for example. But it's worth exploring how they vary from predictions.
Unless they assume some non-conventional time-dependence for the electromagnetic waves such that the time derivative equals the original function. Essentially that would imply a time-dependence going like e^t (the derivative with respect to time of e^t equals e^t) instead of harmonic dependence e^(i*omega*t).
e^t dependence would not be a standing harmonic wave, but it would be a disturbance growing exponentially with time !
Is it too much to hope for a strong divergence from predictions? ;D
http://home.web.cern.ch/about/updates/2015/03/lhcbs-new-analysis-confirms-old-puzzle
Folks:
While you think about possible explanations for the gathering body of data that surrounds the EM-Drive, I've been given permission by Dr. John Brandenburg to post his latest conjecture on how he thinks the EM-Drive AKA Q-Thruster can generate a thrust signal that does not violate the conservations laws. It's not too far off what Dr. White is proposing, but it's just different enough to be of interest especially to the GRT crowd.
Best, Paul M.
Moreover the Nexus graviton can also be considered as a globule of vacuum energy which can merge and de-merge with others in a process that resembles cytokineses in cell biology.
The Nexus graviton is Dark Matter and constitutes space-time. The emission of a graviton of least energy by a high energy graviton results in the expansion of the high energy graviton as it assumes a lower energy state. This process manifests as Dark Energy and takes place throughout space-time as the theory explains.
Ephraim Shahmoon, Gershon Kurizki (Weizmann Institute of Science) and Igor Mazets calculated what happens to vacuum forces between atoms when they are placed in the vicinity of an electrical transmission line such as a coaxial cable or a coplanar waveguide (a device used in cavity quantum electrodynamics experiments as an open transmission line), cooled to very low temperatures. "In that case, the fluctuations are effectively confined to one dimension," says Igor Mazets. The virtual particles will be forced to go into the direction of the other atom.
In that case, the fluctuation-mediated attraction between the atoms becomes orders of magnitude stronger than in free space. Usually, the force decreases rapidly with increasing distance between the atoms. Due to the transmission line, it falls off with one over the distance cubed, instead of one over the seventh power of the distance, as in the usual case.
Attached are VSWR plots for the unloaded frustum configuration currently in my possession between 2400-2500mhz. The cursors are at the MIN VSWR. The peaks of each plot is a VSWR of 99.Would like to perform some calculations of Poynting vector, etc.
...
Attached are VSWR plots for the unloaded frustum configuration currently in my possession between 2400-2500mhz. The cursors are at the MIN VSWR. The peaks of each plot is a VSWR of 99.Would like to perform some calculations of Poynting vector, etc.
...
What are the geometrical dimensions of your truncated cone?
Internal Diameter of Big Base = ?
Internal Diameter of Small Base = ?
Internal Axial Length (perpendicular to the bases) = ?
@Paul March, what do you recommend doing with the sample port on the frustum during actual force measurements?
It seems that leaving a 50ohm termination on there during the actual force testing will just ensure energy will get coupled back out of the cavity and into the load, which is what I don't want to happen.
Should I leave it terminated with a termination with a very low rating? Or should I remove the probe inside? Or should I just remove the connector and tape over it with copper tape? Connect it to some test equipment? Something else?
What do you do?
Thanks for all that you are doing.
@Paul March, what do you recommend doing with the sample port on the frustum during actual force measurements?
It seems that leaving a 50ohm termination on there during the actual force testing will just ensure energy will get coupled back out of the cavity and into the load, which is what I don't want to happen.
Should I leave it terminated with a termination with a very low rating? Or should I remove the probe inside? Or should I just remove the connector and tape over it with copper tape? Connect it to some test equipment? Something else?
What do you do?
Thanks for all that you are doing.
Not NASA here, of course, but I would just leave the connector "open", ie. high impedance. (what impedance are you looking into as a monitor ?)
My personal favorite would be to use it as feedback in an oscillator configuration. (I'm "biased" )
Folks:
While you think about possible explanations for the gathering body of data that surrounds the EM-Drive, I've been given permission by Dr. John Brandenburg to post his latest conjecture on how he thinks the EM-Drive AKA Q-Thruster can generate a thrust signal that does not violate the conservations laws. It's not too far off what Dr. White is proposing, but it's just different enough to be of interest especially to the GRT crowd.
Best, Paul M.
Can you use your analyser in a reflectometer configuration ?
Can you use your analyser in a reflectometer configuration ?
Um, no I don't think it can do that. I have an Agilent E4443A, and also an 8562A and 8562EC to use. I can't take test equipment home from work anyway. So all I can do is test at work to get data, then use the data at home.
I've had to work all weekend, so that's why I'm in test mode instead of building things and trying to find a lathe to use..... ;)
@ Star-Drive
"EDIT 4: @Star-Drive: up-thread the participants were trying to get your attention on the reverse thrust condition."
-from Stormbringer
Thanks
@ Star-Drive
"EDIT 4: @Star-Drive: up-thread the participants were trying to get your attention on the reverse thrust condition."
-from Stormbringer
Thanks
Notsosureofit:
The reverse thrust signals for the 1937.15MHz thrust signals are not the negative going mirror images of the forward or positive going thrust signatures as one would have liked. I'm still trying to understand why this is so, but I think it means that the force measurement system is not symmetric in its response to left and right going force inputs at the low thrust magnitudes we are currently having to put up with, since I've already shown that the frustum produces similar thrust values both inside and outside the stainless steel vacuum chamber. I've appended two slides to this post that show the forward and reverse signals in-air on one slide at 50W and then just the reverse thrust signal in-vacuum at 35W. I've also appended the frustum out of the vacuum chamber thrust run, noisy as it is for your inspection.
Bottom line to all this is we need more thrust to work with and from our current COMSOL/QV-Plasma Code runs now for the TM010 mode at 942 MHz, its becomes very apparent we really need to increase our power levels into the 1.0-to-10kW-rf range or even higher. And yes they may validate the magnitude of thrust data that Shawyer's and Chinese's reported even without dielectrics in the cavity. Of course one data point is only suggestive, but it sure points us to where we have to go to truly validate these conjectures. However that course of action requires resources that are at present not available to the Eagleworks lab...
BTW, these COMSOL/QV-Plasma Code thrust predictions may be reporting up to an order of magnitude low from what the real test article will generate at the noted power levels as shown in the last appended slide.
Best, Paul M.
@ Star-Drive
Have there been any experimental runs that show force towards the big end ??
@ Star-Drive
Have there been any experimental runs that show force towards the big end ??
All:
1. For my post of earlier today reversed thrust means physically reversing the frustum test article 180 degrees from its previous "forward" position.
2. I've also observed several test setups that generated reversed thrust signatures without physically turning the thruster around 180 degrees in its mount. One of these instances was with the current copper frustum and the others were with my two Mach Lorentz Thrusters (MLT) as reported in my STAIF-2006 paper. Thrust reversal was obtained in those test setups by reversing the E-field & B-field drive polarities via relay control.
Best, Paul M.
Mulletron:
In regards to your sense antenna port on the copper frustum, when not being used for taking VNA S21 frequency sweep plots I either leave our sense antenna as an open circuit, AKA in a high-Z state, or use it as a feedback control signal for our phase locked loop (PLL) circuit. If the latter, I still have to make the E-field sense antenna in the frustum very small, (like just the solder cup on an SMA bulkhead connector), so as to not overload the PLL's mixer input. Even with this small of an antenna, I still have to add at least 40 dB of 2W each 5-to-10 dB attenuator pads to the sense antenna's output to keep the PLL's mixer circuit from overloading. And the higher the Q-factor of the mode under study, the more sense antenna padding isolation that is required.
Best, Paul M.
@ Star-Drive
Have there been any experimental runs that show force towards the big end ??
All:
1. For my post of earlier today reversed thrust means physically reversing the frustum test article 180 degrees from its previous "forward" position.
2. I've also observed several test setups that generated reversed thrust signatures without physically turning the thruster around 180 degrees in its mount. One of these instances was with the current copper frustum and the others were with my two Mach Lorentz Thrusters (MLT) as reported in my STAIF-2006 paper. Thrust reversal was obtained in those test setups by reversing the E-field & B-field drive polarities via relay control.
Best, Paul M.
The bell just tolled: my understanding of what "reverse" meant in your plots was therebydefenestratedcorrected :)
Is there a position vs. time plot of the "One of these instances ... with the current copper frustum" with the force directed towards the big end? If so, can you make that plot available?
What was the frequency, mode shape, thrust force, Q, input power and testing environment corresponding to the case exhibiting a thrust force pointed towards the big base?
It is very important to report this case because itdefenestratesnullifies mechanistic theories proposed to explain the NASA Eagleworks measurements as an experimental mechanical artifact having no application whatsoever for spaceflight applications.
Dr. Rodal:
The copper frustum thrust reversal due to only its dielectric placement came when I was experimenting with the TM010 mode, when I cut back the HDPE disc count to one, while the copper frustum was mounted in its little OD pointed to the right or forward position.
I then removed the HDPE disc ...
... and replaced it with one 5.13" OD by 1.06" thick PTFE discs that was mounted at the large OD end of the copper frustum with the frustum still mounted in the same direction as the first TM010 test, i.e., with its small OD end pointed toward the right in the vacuum chamber.
The attached slides summarizes these two test series at 954MHz (1 HDPE Disc at which OD end ?) and 901 MHz (1 Teflon Discs at Large OD end).
http://www.dtic.mil/dtic/tr/fulltext/u2/a564120.pdf?
"Demonstration of a wingless electromagnetic air vehicle"
Pretty much proof-of-concept, goes into lots more detail than I have endurance to read.
This finding indicates that the photons all moved at the same speed, even though different photons had different energies. This is one of the best measurements ever of the independence of the speed of light from the energy of the light particles.
Beyond confirming the general theory of relativity, the observation rules out one of the interesting ideas concerning the unification of general relativity and quantum theory. While these two theories are the pillars of physics today, they are still inconsistent, and there is an intrinsic contradiction between the two that is partially based on Heisenberg's uncertainty principle that is at the heart of quantum theory.
One of the attempts to reconcile the two theories is the idea of "space-time foam." According to this concept, on a microscopic scale space is not continuous, and instead it has a foam-like structure. The size of these foam elements is so tiny that it is difficult to imagine and is at present impossible to measure directly. However light particles that are traveling within this foam will be affected by the foamy structure, and this will cause them to propagate at slightly different speeds depending on their energy.
Yet this experiment shows otherwise. The fact that all the photons with different energies arrived with no time delay relative to each other indicates that such a foamy structure, if it exists at all, has a much smaller size than previously expected.
Whatever, I second Dr Rodal: despite using advanced concepts, with only electricity and no fuel on board, and having an unusual odd shape, those conceptual flying saucers are not propellantless thrusters, since they have to accelerate ambient air for propulsion. This is leading-edge, but still classical physics.
....Paul,
The copper frustum thrust reversal due to only its dielectric placement came when I was experimenting with the TM010 mode,...
Hey @Rodal, would you mind telling us more about what sources and methods you are using or have developed that allowed you to generate these original and colorful simulations in these posts:Yes, it would be a good idea to summarize them (when I have a chance to do it :) )
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1348295#msg1348295
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340906#msg1340906
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340909#msg1340909
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1341244#msg1341244
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1344664#msg1344664
It is quite evident that over the course of this lengthy discussion, you have developed tools and methods which can be helpful to many others. Can you give us a summary of what you can do now?
If I'm understanding this right is there a kind of catch 22 at work here. To validate if this drive works or not you need a greater power input, but to obtain access to a greater power input it has to be proved that it works first?
Ok, here's a crazy idea;
Is it not possible that what is being seen with the EM drive is not so much actual thrust, although the effect detects as such, but possibly an alteration of space itself? Perhaps compactifycation on an almost infitismal scale?
Ok, here's a crazy idea;
Is it not possible that what is being seen with the EM drive is not so much actual thrust, although the effect detects as such, but possibly an alteration of space itself? Perhaps compactifycation on an almost infitismal scale?
If that's the case, then it could be a good idea to stick fully enclosed accelerometers close to the Emdrive, at several distances, for finding out if there is any residual effect in its vicinity...
Has anyone done such a thing?
I just made some minor improvements to the he Poynting vector plotting code and thereby updated the images shown on http://forum.nasaspaceflight.com/index.php?topic=36313.msg1348295#msg1348295Hey @Rodal, would you mind telling us more about what sources and methods you are using or have developed that allowed you to generate these original and colorful simulations in these posts:Yes, it would be a good idea to summarize them (when I have a chance to do it :) )
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1348295#msg1348295
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340906#msg1340906
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340909#msg1340909
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1341244#msg1341244
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1344664#msg1344664
It is quite evident that over the course of this lengthy discussion, you have developed tools and methods which can be helpful to many others. Can you give us a summary of what you can do now?
My analysis is all based on exact solutions based on classical Electromagnetism (*), which I have discussed earlier in the thread.
I think that @Notsosureofit may have followed some of my earlier discussions.
I wrote Mathematica code to numerically solve the eigenvalue problems in the exact solutions and to plot the solutions.
It is a work in progress: I started with contour plots for fields and later on I wrote the code for the vector plots.
Since the natural coordinates of the exact solution are in spherical coordinates attached to the cone, to plot these fields in Mathematica one has to transform the coordinates and the vectors to a Cartesian field x, y, z. This transformation actually took more time to get just right (because of nonlinearities involving SquareRoots and ArcTan functions that have multiple values) than the time it took to get the exact solutions.
In the course of one of our latest post discussions with @Frobnicat I started by showing the vector components of E and B to make a point about Poynting's vector (no pun intended) and I told myself: hey why don't I just calculate and plot Poynting's vector ? (NASA Eagleworks did not show us COMSOL plots of Poynting's vector: don't know whether COMSOL can do this easily ...)
My next step was going to be to calculate more exact solutions (including the dielectric) but I am spending more time on these plots. For example, depending on the discussion it may be interesting to plot Maxwell stress tensors components and/or the components of the 3+1 spacetime relativistic energy-stress tensor ...
And I'm immediately interested in examining Poynting's vector direction for a number of modes in NASA Eagleworks truncated cone to see whether there is any mode clearly pointing in the direction of the big base. So far all the modes I have examined have a Poyinting's vector very clearly directed towards the small base and other ones have a Poynting's vector that may be zero or very small in the opposite direction.
Which means that I should also write Mathematica code to integrate Poynting's vector for the cases in which it is not visually clear which way the overall integral over the volume is pointing.
______________
(*) As discussed previously, for example the electromagnetic force depends on the derivative of Poynting's vector with respect to time and on the divergence of Maxwell's stress tensor. Poynting's vector goes like (Cos[omega*t])^2 so its derivative with respect to time (2 Cos[omega*t]*Sin[omega*t]) should average zero over each half 2Pi/omega cycle. The divergence of Maxwell's stress tensor should be zero if there are no electromagnetic sources inside the cavity. (Notice that Brandenburg assumes sources inside the cavity to arrive at his explanation).
Ok, here's a crazy idea;
Is it not possible that what is being seen with the EM drive is not so much actual thrust, although the effect detects as such, but possibly an alteration of space itself? Perhaps compactifycation on an almost infitismal scale?
If that's the case, then it could be a good idea to stick fully enclosed accelerometers close to the Emdrive, at several distances, for finding out if there is any residual effect in its vicinity...
Has anyone done such a thing?
I think it might be worth doing but i see a few problems.
The current investigation at the device itself is attempting to detect micro-newton scale thrust signals. gravity effects fall of drastically at distance. so presumably any gravitic/spacetime distortion effect at distance would be all that much smaller and therefore that much harder to detect.
Dr White's other experiment is based on just such an effect and it has not risen according to publicly disclosed reports comfortably above sigma and that laser interferometry is extremely sensitive.
The current activity is under deadline pressure. I think they have until the end of the month to get a 100 micro-newton signal to justify independent replication efforts. This makes changing the protocol drastically perhaps a destructive course of action. Something does need to be done but probably on stuff like the power input or waveforms or the device itself rather than the detection protocol. Unless it can be done without delaying the work or invalidating the data.
Ok, here's a crazy idea;
Is it not possible that what is being seen with the EM drive is not so much actual thrust, although the effect detects as such, but possibly an alteration of space itself? Perhaps compactifycation on an almost infitismal scale?
From what I've been able to gather, it would detect as actual thrust due to movement of the test article, due to the tiny amount of actual distortion, it wouldn't even be visible optically, unless using an extremely sensitive spectrometer for light frequency shifting in the area of the device. I realize that the power calculated to create such a distortion are several orders of magnitude greater than what is being used here, but Einstien suggested that Gravity should be able to be manipulated in a fashion similar to electromagnetism.
Is it possible that someone has stumbled onto just such a method USING electromagnetism? Or, it could be some form of enhancing of the Nuclear Strong or Nuclear Weak forces. However, I suspect that manipulation of a local EM field of sufficent local intesity, could alter space within the same volume, assuming the concept of Inflation is correct.
If I'm understanding this right is there a kind of catch 22 at work here. To validate if this drive works or not you need a greater power input, but to obtain access to a greater power input it has to be proved that it works first?I fear it is worse then that, because when you resort to more power input the thermal effects on the frustrum will also increase, with a dramatic negative effect on the Q.
However, if the effect is not gravitic in nature but simply a distortion of space, gravity itself may not be involved but the electromagnetic forces themselves may be causing a localized distortion of space, either compression in front or expansion in back. again, this assumes the theory of Spacial Inflation is accurate.
I've taken my own advice, and taken a gamble on using low power and using what I've learned from Cavendish (http://en.wikipedia.org/wiki/Cavendish_experiment), hopefully I can build a sensitive (and simple enough) balance.
I've taken my own advice, and taken a gamble on using low power and using what I've learned from Cavendish (http://en.wikipedia.org/wiki/Cavendish_experiment), hopefully I can build a sensitive (and simple enough) balance.
I was thinking earlier if you all might have designed a flexible beam and have a mirror mounted on the engine. You could then use interferometry to get very accurate changes in position when the beam flexes if there is a force acting on it. There might need to be a lot of dampening to reduce noise from vibrations though.
Another thought hit me regarding why this drive would make a force. It strikes me as similar to the idea in the thread "E/M propellant-less propulsion using delayed information/dielectrics (patent)" in that there may be some time delay of information going on inside the cavity plates. It appears there are circulating currents in the device due the changing magnetic fields. However, that information doesn't travel instantaneously. Maybe what could be happening is that the circulating currents in the bottom plate observe the circulating current in the top plate as circulating in the same direction and so they are attracted to the top plate. However, the top plate may observe the bottom plate having current circulating in the opposite direction and so it is repelled from the bottom plate. The result is a unidirectional force. In other words the currents in the top and bottom plates are about 90 degrees out of phase?
I don't know if the delay in propulsion fits with that but maybe it takes a bit for the cavity to reach its final resonant state and then a while for the radiation to die away inside.
If not the top plate interacting with the bottom plate then maybe the top plate interacting some distance down the side walls such that the magnetic fields are 90 degrees out of phase in time.
And here's a sample of the spectrum analyzer test. All this test involves is injecting a calibrated 0dbm input signal to the frustum, then seeing what comes out the other side on the spectrum analyzer.
*HP 83752B Sweep generator @0dbm
*Agilent E4443A spectrum analyzer
*Gigatronics 8542C power meter w/*80301A sensor
(2) 6' high quality test cables
*=Calibrated by a lab
Combine this with the VSWR data and the behavior of the unloaded frustum between 2400-2500mhz becomes apparent. The points where the VWSR is really poor is evident in the amplitude response, seen in the spectrum analyzer shots, so these two tests validate each other.
Rest is here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoUEx5dzlVTG81a2c&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
Other frequencies here:
(disclaimer, my E field probe is not optimized for all these frequencies, still useful to see what other frequencies couple to the cavity with low VSWR using my 31mm probe/cavity combination)
The best peaks of other frequencies are labeled similar to the bottom screen shot.
https://drive.google.com/folderview?id=0B4PCfHCM1KYoVkRzUGNuMVBLbVk&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
@aeroI don't know. The physical dimensions of the thruster models range over several orders of magnitude from the smallest dimension of interest to the overall size of the cavity. That makes it almost a supercomputer problem. I could do better work with a faster computer but that computer runs $2500 USD and I'm sure there are a lot of members here who would like to have a new computer. And that faster computer would only allow me to set-up problems at low resolution which should be verified on a supercomputer.
Is there any way the community here can help by donating some computer time to run different simulation scenarios?
Can they be packaged up so that an inexperienced user can just run them and then email/post the results?
....We can readily calculate the electromagnetic fields (and associated electromagnetic quantities) for the EM Drive.
Maybe what could be happening is that the circulating currents in the bottom plate observe the circulating current in the top plate as circulating in the same direction and so they are attracted to the top plate. However, the top plate may observe the bottom plate having current circulating in the opposite direction and so it is repelled from the bottom plate. The result is a unidirectional force. In other words the currents in the top and bottom plates are about 90 degrees out of phase?
I don't know if the delay in propulsion fits with that but maybe it takes a bit for the cavity to reach its final resonant state and then a while for the radiation to die away inside.
If not the top plate interacting with the bottom plate then maybe the top plate interacting some distance down the side walls such that the magnetic fields are 90 degrees out of phase in time.
the circulating currents in the bottom plate observe the circulating current in the top plate as circulating in the same direction and so they are attracted to the top plate. However, the top plate may observe the bottom plate having current circulating in the opposite direction and so it is repelled from the bottom plate. The result is a unidirectional force.
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
(There are three ~1.00" 1/4-20 nylon bolts mounted on a ~2.00" radius spaced every 120 degrees that hold the first PE disc to the PCB end cap. There is then a layer of 3/4" wide office scotch tape at the interface between the first and second PE discs and the center 1/4"-20 nylon bolt that hold second PE disc to the first PE disc.)
it looks like there is a high E-field volume where this center nylon bolt hangs out while running in the TM212 resonant mode.
we tested the copper frustum in its TM010 mode and mounted a 5.0 inch OD by 1.0" thick PTFE disk at the center of the large OD end cap of the copper frustum with one 1/4-20 nylon bolt.
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
Congratulations on your build progress!
As for the HDPE mounting solution...
If the initial intention is to replicate the Eagleworks' configuration, I'd propose mimicking the Eagleworks' mounting technique. I've seen at least two different bolt hole patterns in posted images, and some of the verbiage suggesting that different bolt hole patterns are best for different excited modes. ...
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
QUESTION 1: Before mounting the discs, could you please run a couple of tests without the HDPE discs?
If, so I can send you a post showing the mode shapes at the two frequencies near 2.45 GHz and why .
There is a mode shape at 2.49 GHz (or at 2.46 GHz according to NASA's COMSOL calculations) that should produce no force without the dielectric disc (because the Poynting vector practically cancels out)
There is a mode shape at 2.46 GHz (or at 2.41 GHz according to NASA's COMSOL calculations) that may produce an electromagnetic force without the dielectric disc (because the Poynting vector does not cancel out)
QUESTION 2: Do you have access to a thermal IR camera (to identify the mode shapes, etc.) ?
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
Congratulations on your build progress!
As for the HDPE mounting solution...
If the initial intention is to replicate the Eagleworks' configuration, I'd propose mimicking the Eagleworks' mounting technique. I've seen at least two different bolt hole patterns in posted images, and some of the verbiage suggesting that different bolt hole patterns are best for different excited modes. (as an aside, since the bolt holes pierce both the dielectric and the copper frustum's plate, I've wondered what the RF field looks like outside of the cavity near those holes; I don't recall seeing any bolt holes in the previously posted/discussed meep sims)
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
Congratulations on your build progress!
As for the HDPE mounting solution...
If the initial intention is to replicate the Eagleworks' configuration, I'd propose mimicking the Eagleworks' mounting technique. I've seen at least two different bolt hole patterns in posted images, and some of the verbiage suggesting that different bolt hole patterns are best for different excited modes. (as an aside, since the bolt holes pierce both the dielectric and the copper frustum's plate, I've wondered what the RF field looks like outside of the cavity near those holes; I don't recall seeing any bolt holes in the previously posted/discussed meep sims)
My leading intention is to use the 3 Nylon bolt approach like Paul March, but it really pains me to drill holes into perfectly good dielectric resonators. All the Nylon bolts I have at the moment aren't long enough, and if the holes are too big, RF can escape.
I'm looking for a better way if there is one.
If your copper in the endplate is thick enough, surface roughening of the copper and of the HD PE results in mechanical interlocking sites and causes bond strength to increase dramatically.
My leading intention is to use the 3 Nylon bolt approach like Paul March, but it really pains me to drill holes into perfectly good dielectric resonators. All the Nylon bolts I have at the moment aren't long enough, and if the holes are too big, RF can escape.
I'm looking for a better way if there is one.
Quotetried epoxy and superglue bonding the PE and PTFE discs to the frustum end-caps, but these two plastics just happen to be the slickest and hardest plastics to bond to anything else. Drat!The marine adhesive made by 3M (5200 or 5220 fast cure) will stick to anything
I don't understand the (analogy ?) in the following statement:Quotethe circulating currents in the bottom plate observe the circulating current in the top plate as circulating in the same direction and so they are attracted to the top plate. However, the top plate may observe the bottom plate having current circulating in the opposite direction and so it is repelled from the bottom plate. The result is a unidirectional force.
How are the circulating currents in the bottom plate "observing" the circulating currents in the top plate?
The magnetic electromagnetic fields are out of phase (see the plots below). Why would the bottom circulating current "observe" the top one as circulating in the same direction: "in phase"?
(Dustinthewind - [bold with my name is me] in other words information only travels at the speed of light or , dx=c*dt. The key to the image attached is:
Reference Numeral - Diagram illustrations as shown in FIGS. 1-2:
1 - Electromagnetic force
2 - Current in upper wire
3 - Current in middle wire
4 - Current in lower wire
5 - Apparent current of the upper wire
6 - Apparent current of the middle wire
7 - Apparent current of the lower wire
8 - Frame one of six
9 - Frame two of six
10 - frame three of six
11 - frame four of six
12 - frame five of six
13 - frame six of six
The image only considers parallel wires but the idea could be extended to make the wires equivalent to the circulating currents in the top and bottom plates or maybe the top plate and some distance down the sidewalls.
P.S. the diagram considers three wires but the simplest to consider is only two wires. Ignore one color if you like as they are color coded depending on the wire and limit to two wires. In the three wire diagram the top and bottom wires are out of phase 180 degrees so there is no unidirectional force between them. The wires next to each other are only 90 degrees out of phase. In time what happens is the bottom wire observes the current above it as moving in the same direction = attraction. The top wire observes the current below it as moving in the opposite direction = repulsion
)
And most important, how does this get around the conservation of momentum problem (if one considers the EM Drive as a closed system with no internal sources) ?(Dustinthewind - here is a quote from the other thread, "A scientific paper that clarifies how newtons 3rd law does not apply to the time delay of information and how it can be used for electromagnetic propulsion. It provides a mathematical background for the time delayed magnetic fields but first illustrating how the static equations miss the effect. https://scholar.google.com/scholar?cluster=7136673109349846373&hl=en&as_sdt=0,48" it is titled, "Newton's Third Law in the Framework of Special Relativity" )- Dustinthewind - Please disregard this reference as I was in error in assuming this paper was dealing with two current loops changing in time 90 degrees out of phase.
Assuming no internal magnetic sources (no magnetic monopoles) and no internal electric sources, the divergence of Maxwell's stress tensor is zero (due to the lack of internal sources inside the cavity).
The derivative with respect to time of Poynting's vector is zero (if the electromagnetic fields are a harmonic function of time). These conditions lead to no electromagnetic force on the center of mass, even when considering a fully general-relativistic formulation of the principle of conservation of energy-momentum (http://en.wikipedia.org/wiki/Electromagnetic_stress%E2%80%93energy_tensor#Conservation_laws ), because the divergence (in 3D+1 spacetime) of the stress–energy tensor is zero under those previously-stated conditions.
In order to have a force and acceleration of the EM Drive one needs electromagnetic sources inside the EM Drive cavity (as assumed for example in Brandenburg's equations) and/or the electromagnetic fields to be a nonlinear non-harmonic function of time.
(Dustinthewind - It sounds like you have already considered the time dependent interactions from the sound of it so maybe I'm wrong in speculating on the propulsive effect.)
If your copper in the endplate is thick enough, surface roughening of the copper and of the HD PE results in mechanical interlocking sites and causes bond strength to increase dramatically.
I asked this before but my question wasn't answered (perhaps it is a stupid question):
Wouldn't roughening the copper internal surface of the end plates (to better bond the glue) dramatically reduce the surface reflectivity, hence the Q factor of the cavity?
If your copper in the endplate is thick enough, surface roughening of the copper and of the HD PE results in mechanical interlocking sites and causes bond strength to increase dramatically.
I asked this before but my question wasn't answered (perhaps it is a stupid question):
Wouldn't roughening the copper internal surface of the end plates (to better bond the glue) dramatically reduce the surface reflectivity, hence the Q factor of the cavity?
Good point, I presume that surface roughness features with height comparable to the penetration length would have a significant effect on the power loss ratio, so I deleted the mention of roughening to improve adhesion.
The effect of roughening on polyethylene does not seem to have universal acceptance: Loctite (see report below) states that they did not find a statistical difference when bonding LDPE (they don't say anything about roughening HD PE)
That leaves solvent-based primers as a good option to improve adhesion.
Look at page 51 of this report from Henkel North America (Loctite): http://www.henkelna.com/us/content_data/237471_LT2197_Plastic_Guide_v6_LR7911911.pdf
which are specifically recommended for polyethylene (a very hard to bond polymer)
(Ethyl Cyanoacrylate) Loctite 401 Prism from Amazon:
http://www.amazon.com/Loctite-Instant-Adhesive-Prism-Bottle/dp/B006GOKRSY/ref=pd_sim_sbs_indust_1?ie=UTF8&refRID=14RMFHYMSB2780RR33CY
Primer for Loctite 401 Prism from Amazon:
http://www.amazon.com/Loctite-LOC-18396-770-Cyanoacrylate-Adhesive/dp/B001OBQ8VO/ref=sr_1_fkmr0_1?s=hi&ie=UTF8&qid=1427237585&sr=1-1-fkmr0&keywords=Loctite%C2%AE+770%E2%84%A2+Prism%C2%AE+Primer
THIS GLUE IS STRONG AND FAST ACTING - MAKE SURE TO WEAR GLOVES AND PROTECT YOURSELF
https://scholar.google.com/scholar?cluster=7136673109349846373&hl=en&as_sdt=0,48....
....
Most locomotive systems of today are based on open systems. A rocket sheds exhaust gas to propel itself, a speeding bullet generates recoil. A car pushes the road with the same force that is used to accelerate it, the same is true regarding the interaction of a plane with air and of a ship with water. However, the above relativistic considerations suggest’s a new type of motor which is not based on a open system but rather on a closed one
....
As a final remark we will address the problem of achieving constant force which may be of interest for locomotive applications. A constant force may be achieved by having a direct current in one loop and a current of uniform second derivative on the other. For the choice of values given in table 2 we obtained FT z ∼= 2.74 Newton.
Obviously the switching time may represent some difficulty which one may overcome with advanced enough switching technology perhaps using low resistivity superconducting materials. Another possibility for constructing a relativistic motor is using numerous modular solid-state devices each with fast switching and small current such that an appreciable amount of cumulative forcing will result.
I have been examining higher modes for the truncated cone cavity and mode shapes for truncated cones with larger cone angle and for smaller base diameters at the same cone angle........ I think that this mode shape correct designation is TM011 instead of TM010 because:
The copper frustum thrust reversal due to only its dielectric placement came when I was experimenting with the TM010 mode,...
1) There can be no TMmn0 modes for a truncated cone. TMmn0 modes need to have a constant electromagnetic field in the longitudinal direction of the cavity. This is possible for a cylindrical cavity (containing no other dielectrics inside besides the cavity medium) because it has constant geometrical and material properties in the longitudinal direction. But a conical cavity has variable cross-section in the longitudinal direction, therefore the TMnn0 mode is not possible. The first possible mode (if it is not cut-off) is TMmn1. The exact solution for the truncated cone shows this. See for example: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html :The quantum mode number "p" for a truncated cone is related to k. k cannot be zero for a truncated cone, since k = ω/c for a truncated cone , therefore k = 0 implies zero frequency for a truncated cone.
2) As the attached plot shows, COMSOL's FEA plot shows an electromagnetic field that is not constant in the longitudinal direction, therefore this is not TM010, it looks instead as TM011 upon closer inspection.
(Therefore the analyst's designation for TM011 should be changed to TM012 and so forth for TM01p modes)
@frobnicat: please notice this paper, published in The European Physical Journal Plus
November 2014, 129:240; which was brought up by @dustinthewind:
https://scholar.google.com/scholar?cluster=7136673109349846373&hl=en&as_sdt=0,48
that states:Quote from: Miron Tuval and Asher Yahalom Newton’s Third Law in the Framework of Special
RelativityMost locomotive systems of today are based on open systems. A rocket sheds exhaust gas to propel itself, a speeding bullet generates recoil. A car pushes the road with the same force that is used to accelerate it, the same is true regarding the interaction of a plane with air and of a ship with water. However, the above relativistic considerations suggest’s a new type of motor which is not based on a open system but rather on a closed one
....
As a final remark we will address the problem of achieving constant force which may be of interest for locomotive applications. A constant force may be achieved by having a direct current in one loop and a current of uniform second derivative on the other. For the choice of values given in table 2 we obtained FT z ∼= 2.74 Newton.
Obviously the switching time may represent some difficulty which one may overcome with advanced enough switching technology perhaps using low resistivity superconducting materials. Another possibility for constructing a relativistic motor is using numerous modular solid-state devices each with fast switching and small current such that an appreciable amount of cumulative forcing will result.
The European Physical Journal arose in 1998 as a merger and continuation of the very prestigious journals Zeitschrift für Physik, Journal de Physique, Il Nuovo Cimento, and other journals.
The authors are associated with the renowned Isaac Newton Institute for Mathematical Sciences, an international research institute for mathematics and theoretical physics adjoining the Cambridge University Centre for Mathematical Sciences. In 1993 the British mathematician Andrew Wiles announced at the Institute his proof of Fermat's last theorem. Its director as of May 2012 was Cambridge University Professor John Toland (who is famous for formally proving in 1978, Stokes' conjecture on the existence of gravity waves of maximum height on deep water, a previously open problem in mathematical hydrodynamics which dated back to the 19th century).
The idea is correct, often used to demonstrate the twin paradox in General Relativity not Special Relativity. (My pet peeve) Special is only for Inertial frames. Forces and acceleration require General Relativity, so they wind up using the limit of an approximation instead.
Edit: I have to read this paper in more detail, but first glance, it looks like you might get an impulse during this rather select interval but I don't (yet) see any consideration of the recovery of initial conditions w/o reversing it.
FYI
http://www.technologyreview.com/view/536091/spacecraft-traveling-close-to-light-speed-should-be-visible-with-current-technology-say/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+arxivblog%2FGmoU+%28The+Physics+arXiv+Blog%29
The movement of a relativistic spacecraft will have another effect. It should scatter the cosmic microwave background in a way that produces a unique signature. “As a baryonic spacecraft travels at relativistic speeds it will interact with the CMB through scattering to cause a frequency shift that could be detectable on Earth with current technology,” say Yurtsever and Wilkinson.
After your demolishing review, I decided to look into more detail into the Jounal, and I noticed the "Plus" at the end (instead of A or B).The idea is correct, often used to demonstrate the twin paradox in General Relativity not Special Relativity. (My pet peeve) Special is only for Inertial frames. Forces and acceleration require General Relativity, so they wind up using the limit of an approximation instead.
Edit: I have to read this paper in more detail, but first glance, it looks like you might get an impulse during this rather select interval but I don't (yet) see any consideration of the recovery of initial conditions w/o reversing it.
I second you on the (also at first glance) apparent problem of having any kind of stationary net average force in a direction with this approach. From the article (at least what is on arxiv (http://arxiv.org/pdf/1302.2537v1.pdf)) : the meat is equation (66) F=cst*I1bar*I2bar/tau² (number of turns assumed constant).
I don't know the academic history and prestige of the journal in which this is published, but unless the published version is significantly edited, this is a case of notation abuse and almost deceit in conclusion drawing from correct equations, (I assume they are correct, would took me some weeks to understand and check in details). The bar notation usually denotes a time averaged value of a time varying stationary value, be it periodic, or quasiperiodic, or random, but it must be that ( integral(0 to T) V(t)dt )/T converges to some value when T->+infinity for Vbar to have a meaning. Unless there are other usages I'm unaware of ? Please educate me if so.
Anyway (bottom page 12) : A constant force may be achieved by having a direct current in one loop I1(t) =I1bar and a current of uniform second derivative on the other I2(t)=1/2 I2bar*t²/tau²
Green sensible use of bar notation
Red deceiving use of bar notation : I2(t) defined as having a uniform second derivative (wrt time) can't be stationary. I2bar is ill defined. For instance if a given I2(t) is defined by I2bar=1 and tau=1, the exact same I2(t) could also be defined by by I2bar=100 and tau=10. There are 2 "free parameters" introduced when in fact saying "uniform second derivative" requires only one : I2(t) = 1/2 CurAcc*t² where CurAcc (Current Acceleration) is the only needed parameter and has units of A/s². This might be ugly, maybe a "representative" current value in A (I2bar) + "representative" time value in s (tau) is more "expressive" and elegant. As absolute values, it's not clear what they are representative of though, since 1A 1s is equivalent to 100A 10s
But abuse of notation and introducing more parameters than necessary is not the problem by itself, and the equation (66) is still as valid written with I2bar/tau² term as it would be with CurAcc term. Equations all right. But then we forget that I2bar notation was just a commodity, that there is no real stationary I2(t) behind that, and that the force given by the expression can only be a transient, since 1/2 CurAcc*t² will soon exceed any reasonable current carrying capacity (superconducting or not). And assuming a clever possibility, like cutting the current abruptly (in the loop) to put it back to 0 periodically, is doomed to fail as much as any attempt to transform repetitive mechanical effects inside a capsule into net acceleration (Dean drive...). What was gained during an acceleration phase will be lost by a deceleration phase, if the driving parameter (Intensity, Position...) is to be made periodic.
This derives clearly from eq. (51) (from which eq. (66) itself derives) :
F(t) proportional to I1(t)*I2dotdot(t) - I1dotdot(t)*I2(t)
Is it conceivable to have 2 stationary I1(t) and I2(t) (in the sense defined above that I1bar and I2bar have a real meaning) that yield Fbar different from 0 ? I don't see a clever elegant mathematical proof to that but I'm rather sure it is impossible. If someone disagree please state a clear explicit counter example I1(t) I2(t) (for any t) with Fbar different from 0 and I1 and I2 stationary, that is ( integral(0 to T) I(t)dt )/T converges to some value (0 or whatever) when T->+infinity.
The example I1 constant and I2 "uniformly accelerated" given by the paper don't meet the requirement : I2 not stationary. This is a one shot effect. It's not really different from shooting a bullet at constant m/s² in a mass driver fixed to the hull of a spacecraft. As long as the bullet is accelerating in the mass driver, the mass driver gives a constant "thrust" to the spacecraft. But then what ? Either the bullet is free to leave the spacecraft : conventional reaction propulsion, spacecraft loses propellent mass. Or else it is "recycled", which implies some deceleration of it to 0 (wrt spacecraft), which will cancel exactly the gained momentum, be it hard or soft is irrelevant (damages or sparks aside).
BTW we also understand that playing with "delayed" forces in relativity it's not surprising to get non null instant forces on a system. If "a system" is an ensemble of elements separated by some distance, then there is not really such thing as an instant force on the system as a whole since there is no such thing as an instant for the system. SR is enough to show that the notion of intrinsic instant is ill defined wrt the system's parts : "instant sum of local forces seen by each part" depend on arbitrary inertial rest frame.
What is going on with hard science those days ? Do brilliant people make a living of writing correct complicated equations to hint at spectacular but delusional conclusions from them ?
What can we look forward to this year in regards to your journal’s content or development?
EPJ Plus is a newly born journal of the EPJ series, a continuation of Il Nuovo Cimento B formely published by the Italian Physical Society. It has been launched in 2011 as an electronic-only journal, with a new interdisciplinary approach in terms of topics and a wider portfolio of possible article formats. EPJ Plus is also meant as a "cascade" journal for the other EPJs. In the last two years, the number of articles published in EPJ Plus has significantly grown and its impact factor expectations are definitely promising. According to the recent editorial policy of the journal, invited contents, grouped in topical "Focus Points", will be boosted and contributions from new fields, such as accelerator physics or physics applied to cultural heritage or to energy, will be strongly encouraged.
(Dustinthewind - here is a quote from the other thread, "A scientific paper that clarifies how newtons 3rd law does not apply to the time delay of information and how it can be used for electromagnetic propulsion. It provides a mathematical background for the time delayed magnetic fields but first illustrating how the static equations miss the effect. https://scholar.google.com/scholar?cluster=7136673109349846373&hl=en&as_sdt=0,48" it is titled, "Newton's Third Law in the Framework of Special Relativity" )
(Dustinthewind - here is a quote from the other thread, "A scientific paper that clarifies how newtons 3rd law does not apply to the time delay of information and how it can be used for electromagnetic propulsion. It provides a mathematical background for the time delayed magnetic fields but first illustrating how the static equations miss the effect. https://scholar.google.com/scholar?cluster=7136673109349846373&hl=en&as_sdt=0,48" it is titled, "Newton's Third Law in the Framework of Special Relativity" )
I'll have to apologize if I wasted anyone's time. I realized the paper is not what I thought it was about after frobnicat's review. I expected two current loops changing in time out of phase but per the review I went back and sure enough it is about a current loop constantly on while one changes. :-[
Very interesting paper! Especially considering what Roger Shawyer says about conservation of momentum in "open systems"… To summarize his point of view, standard Newtonian mechanics and thus the law of conservation of momentum indicate that, no matter what shape the cavity is, the forces exerted upon it from within must balance to zero. Shawyer claims this statement ignores special relativity, in which separate frames of reference have to be applied when velocities approach the speed of light. He declares that in the EmDrive, the system of electromagnetic waves and the waveguide can be regarded as an open system, both having separate frames of reference. He also says this effect is similar to the principle of the laser gyroscope, which is also an apparently closed system device, but where the beams act as if having an external frame of reference (which they have, since the speed of light is constant).
However, Shawyer was severely criticized by the scientific community for this "not even wrong" idea. And frankly, I wonder if Tuval & Yahalom's initial assumption regarding the "transmission of any information limited by the speed of light" is really correct, since it is established the Abraham–Lorentz force and inertial reaction forces are instantaneous. Another counterexample involving instantaneousness is quantum entanglement.
[EDIT]I didn't saw at first that Roger Shawyer's idea is opposite (the "open system") than the "closed system" treatment in special relativity by Miron Tuval & Asher Yahalom. It's weird because both seem to claim the same idea: decoupling the EM effects between two interacting electric circuits.
The authors have a patent application in the US:
https://www.google.com/patents/US20140152227?dq=US20140152227&hl=en&sa=X&ei=D2ITVcTUJ8uigwSb34PoAQ&ved=0CB8Q6AEwAA
i think it would be somewhat similar. i always envisioned it as producing a burst of gamma rays and x rays at the start of a FTL movement and a burst when it comes out of FTL mode. but now you have to add a moving and rising emission spectra as it gets to its top speed prior to warp. and a reverse of this on the other end as it may deaccelerate at the destination.FYI
http://www.technologyreview.com/view/536091/spacecraft-traveling-close-to-light-speed-should-be-visible-with-current-technology-say/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+arxivblog%2FGmoU+%28The+Physics+arXiv+Blog%29QuoteThe movement of a relativistic spacecraft will have another effect. It should scatter the cosmic microwave background in a way that produces a unique signature. “As a baryonic spacecraft travels at relativistic speeds it will interact with the CMB through scattering to cause a frequency shift that could be detectable on Earth with current technology,” say Yurtsever and Wilkinson.
Please excuse the somewhat off topic question, but would this also apply to the interaction of an Alcubierre drive or similar manipulation of space-time with the CMB?
I have been examining higher modes for the truncated cone cavity and mode shapes for truncated cones with larger cone angle and for smaller base diameters at the same cone angle........ I think that this mode shape correct designation is TM011 instead of TM010 because:
The copper frustum thrust reversal due to only its dielectric placement came when I was experimenting with the TM010 mode,...
1) There can be no TMmn0 modes for a truncated cone. TMmn0 modes need to have a constant electromagnetic field in the longitudinal direction of the cavity. This is possible for a cylindrical cavity (containing no other dielectrics inside besides the cavity medium) because it has constant geometrical and material properties in the longitudinal direction. But a conical cavity has variable cross-section in the longitudinal direction, therefore the TMnn0 mode is not possible. The first possible mode (if it is not cut-off) is TMmn1. The exact solution for the truncated cone shows this. See for example: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html :The quantum mode number "p" for a truncated cone is related to k. k cannot be zero for a truncated cone, since k = ω/c for a truncated cone , therefore k = 0 implies zero frequency for a truncated cone.
2) As the attached plot shows, COMSOL's FEA plot shows an electromagnetic field that is not constant in the longitudinal direction, therefore this is not TM010, it looks instead as TM011 upon closer inspection.
(Therefore the analyst's designation for TM011 should be changed to TM012 and so forth for TM01p modes)
For these cases (mode shapes with higher "m" azimuthal quantum number, and those with smaller base diameters compared to the big base diameter) the difference between the truncated mode shapes and the cylindrical mode shape becomes more significant.
Ultimately this was unavoidable, because the only quantum number that the truncated cone and the cylindrical cavity have in common is "m" the azimuthal quantum mode number. The variation along the circumference is described by a harmonic function in both the truncated cone and the cylindrical cavity.
On the other hand, the variation along "n" is described by Associated Legendre P functions in terms of the cone's angle for the truncated cone while it is described in terms of zero Bessel functions of the radial polar coordinate for the cylindrical cavity. Different functions in terms of different variables.
And the variation along "p" is described by Spherical Bessel functions in terms of the spherical radial coordinate for the truncated cone, while it is described in terms of harmonic functions of the longitudinal polar coordinate for the cylindrical cavity. Different functions in terms of different variables.
I have not found in the literature a commonly accepted nomenclature to designate mode shapes for the truncated cone.
Furthermore, for this thread's audience, the cylindrical mode shapes are something that the audience can more immediately relate to, since the cylindrical mode shape nomenclature is found in the literature, and @Notsosureofit's formula is based on an analogy to the cylindrical cavity mode shapes (using the Bessel zero functions to characterize the mode shapes).
Therefore, to better communicate these mode shapes, and to avoid confusion I have decided to identify the truncated mode shapes in future communications as follows:
1. Always specifying the frequency at which they take place.
2. Whenever possible to provide plots to illustrate the actual mode shape.
3. Whenever possible to provide the designation for the closest cylindrical mode shape. I will identify these as "Cyl. TMmnp"
Of course, for high mode numbers and/or large cone angles we will find mode shapes that cannot be described in terms of a cylindrical cavity analogy. In those cases those modes are best described by their frequency and a plot showing the actual mode shape.
Therefore, I will describe what NASA Eagleworks describes as mode TM212 as "Cyl. TM212" from now on.
There is still a discrepancy regarding what NASA Eagleworks describes as mode TM010, which I think should be described "Cyl. TM011" because this mode shape for the truncated cone is not constant along the longitudinal axis of the truncated cone (as NASA Eagleworks's own plot shows).
Mr March; I assume you are far far far more familiar with Dr Woodward's nailing down spurious signals than I but I just got through that portion of his book. He basically nuked every potential source of spurious signal in his apparatus and because he is using a nearly identical set up until you get to the frustrum itself his analysis is germain to this project. He appears to have authoritatively disproved every thing we have considered here WRT spurious signals; leaving the problem of what the thrust signal really results from.
That does not give us the answer to what is going on but it does tell us what it is not.
I guess in replication everyone has to redo that work but I cannot help but feel that it is sort of a waste of time to do that all over again. likewise; since I am pretty sure Dr White and yourself know all about Dr Woodward's spurious signal source crushing that the Eagleworks team has also done the same.
I would therefore assume you guys are very confident you have something real and that it is not explained by mundane errors.
...What a fantastic response !
Dr. Rodal:
I asked our first COMSOL analyst his opinion on this resonant mode naming issue and attached is Frank's comments on same.
Best, Paul M.
....
....
What happens is very neat:
a) strictly speaking, the transverse magnetic field in a conical cavity cannot be constant, hence there cannot be a TM010 mode in a cone. However, for cones that have a cone angle sufficiently small (that is: truncated cones that are close enough to a cylindrical cavity) there are two TM011 modes, the lowest TM011 mode is closest to a constant field, closest to TM010, and the higher TM011 mode is closest to a true TM011 mode. Exactly the same designation chosen by Frank: TM010 for TM011a and TM011 for TM011b.
b) For a cone angle approaching zero degrees (a cone approaching a cylindrical cavity) the magnetic field becomes constant in the longitudinal direction, and TM011a becomes TM010. The same designation chosen by Frank.
c) For higher cone angles (for example for the example considered by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html) and certainly for a cone angle > 30 degrees, the lower TM011 mode ("TM011a") disappears completely, as it is cut-off.
I still think we can violate newtons 3rd law in a way but in another way it is not violated because the propulsion device projects radiation out one end. This looks like radiation propulsion but by sticking a dielectric between the two current loops we can change the speed of light making the two current loops closer or lowering the frequency needed while also getting near field effects? What this does for the radiation projected I'm not exactly sure but I would assume it should intensify. This is assuming none of the current loops have constant current but are both changing in time and out of phase pi/2 (see figure EM Propulsion 2.png).There are many things to discuss here.
I guess the idea was if there was something similar going on inside the radiation cavity though I can't quite say that there is. There is also the issue of the idea that radiation projected is conserving momentum but this is inside a cavity. (see figure EM Propulsion 3.png)
Edit: sorry, changed pi/4 to pi/2
Struck out on finding a lathe to use. My belt sander did a fantastic job too. So now I have 2, 1" thick x 6.25" wide HDPE discs. Now I have to figure out how to mount them....
Where there's a will, there's a way.
QUESTION 1: Before mounting the discs, could you please run a couple of tests without the HDPE discs?
If, so I can send you a post showing the mode shapes at the two frequencies near 2.45 GHz and why .
There is a mode shape at 2.49 GHz (or at 2.46 GHz according to NASA's COMSOL calculations) that should produce no force without the dielectric disc (because the Poynting vector practically cancels out)
There is a mode shape at 2.46 GHz (or at 2.41 GHz according to NASA's COMSOL calculations) that may produce an electromagnetic force without the dielectric disc (because the Poynting vector does not cancel out)
...
I still think we can violate newtons 3rd law in a way but in another way it is not violated because the propulsion device projects radiation out one end. This looks like radiation propulsion but by sticking a dielectric between the two current loops we can change the speed of light making the two current loops closer or lowering the frequency needed while also getting near field effects? What this does for the radiation projected I'm not exactly sure but I would assume it should intensify. This is assuming none of the current loops have constant current but are both changing in time and out of phase pi/2 (see figure EM Propulsion 2.png).There are many things to discuss here.
I guess the idea was if there was something similar going on inside the radiation cavity though I can't quite say that there is. There is also the issue of the idea that radiation projected is conserving momentum but this is inside a cavity. (see figure EM Propulsion 3.png)
Edit: sorry, changed pi/4 to pi/2
Of course the electric field and magnetic fields are two interrelated aspects of a single object: the electromagnetic field tensor in 3D+1=4 spacetime.
But if your loops and images are to be interpreted literally only in terms of electric current loops, please notice that your image then could be interpreted as saying that only TE (transverse electric) modes would produce the effect you are seeking, because only TE modes have the electric field in the azimuthal (circumferential) direction. But notice that NASA Eagleworks is currently successfully testing in a vacuum TM modes (and actually I understand they have a preference for TM modes), for which the magnetic field B has a component only in the azimuthal (circumferential) direction while the electric field E has components perpendicular to the magnetic B field. The electric field has zero component in the circumferential direction for TM modes.
Hopefully the Galinstan doesn't corrode the electrical contacts.
Is there any news about the independent verification and validation? It's very hard to find anything reliable on the web :(If you are referring to the paragraph:
The current plan is to support an IV&V test campaign at the Glenn Research Center (GRC) using their low thrust torsion pendulum followed by a repeat campaign at the Jet Propulsion Laboratory (JPL) using their low thrust torsion pendulum. The Johns Hopkins University Applied Physics Laboratory has also expressed an interest in performing a Cavendish Balance style test with the IV&V shipset.
Hopefully the Galinstan doesn't corrode the electrical contacts.
"http://www5vip.inl.gov/technicalpublications/documents/3314568.pdf" says Galinstan pits copper. The Wikipedia page on Galinstan says it corrodes aluminum.
"http://www.rgmd.com/msds/msds.pdf" says it weakens aluminum, and lists a number of other metals that it tends to alloy with, including gold and silver.
On the way is a thicker sheet of 0.043" copper which will be cut to a 6.75" diameter disc. 3 holes will be drilled at 120 degrees, equally spaced. The difference is that, over these holes, I will permanently solder 3, steel nuts and washers to the outside face. Then any dielectric disc will be bolted through from the inside into these nuts. The mounting bolts will be countersunk into the dielectric, in order to provide a smooth interface. The ends of the nuts (on the outside) will be trimmed and covered with conducting copper tape.
Time to build.
Just an attempt to see it from another angle or perspective...
So far, the focus of the discussion has been concentrated on the small and big plate of the frustum for receiving the presumed forces generated by the electromagnetic fields, but what is that wasn't the case?
What if the internally generated magnetic field forces interact with the sidewalls instead of the front/back ends?
Because of the angled sides, the internal forces on the sides would be diverted towards the front plate.
Compare it to squeezing a soap cone: if a circular force is applied from the outside it will move toward the large plate, however if a force is applied from the inside, it will move towards the smaller plate....(just like Shawyer's rotating test rig)
It would also possibly explain to why there is no force detected in a cylindrical cavity.
I have not yet seen any reasoning (maybe i missed it) to why we're all assuming that forces are generated on the front/back end plates - as currently been discussed - and not on the sides walls?
There appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF
resonator in the thrust chamber. The geometry, location, and material properties of this resonator must be evaluated using numerous COMSOL® iterations to arrive at a viable thruster solution. We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.
...
@frobnicat: does this experiment (NASA reporting no experimental thrust for TE012 without a dielectric, but reporting thrust force with a dielectric) nullify mechanistic theories such as the one you recently proposed? (or did I miss something that salvages your mechanistic conjecture for this case?)
Of course, electromagnetic artifact explanations that rely on Poynting's vector are still viable, if somebody can come up with such an artifact explanation.
....
The position of LDS reading seems "permanently" changed by a "thrust" pulse. This hints at a remanence. Magnetic ? Maybe. From purely thermal mechanistic hypothesis this looks like permanent plastic deformation or hysteresis remanence. The only other place I see indication for a thrust "in the wrong direction" is in this post (http://this post) where there is question of partial melting of nylon bolts... Again, if some experiment go up to melting, then quite a lot could actually be operating around glass transition and some of them near melting. From this site (http://www.ptonline.com/columns/the-effects-of-temperature) : we see here that between around 50°C and 100°C the drop in rigidity is huge, this is much lower than the actual melting (220°C). Glass transition is reversible (I think) but may show hysteresis (no ?). How would a nylon bolt under stress (ie. tensioned) behave in length when cycling around the glass transition, would it loosen the fixed dielectric then hold it tight again (against springy slightly warped end PCB plate, we are talking µm...) ?
(http://d2n4wb9orp1vta.cloudfront.net/resources/images/cdn/cms/0811ptMaterials1a.jpg)
Don't throw thermal mechanistic through the window. Experimental data can put it to the ground, but through the stairway, one downstep at a time. This post will inevitably raise more questions and objections, this is just ongoing speculations, I won't have time to really support all that in the coming days.
http://www.dtic.mil/dtic/tr/fulltext/u2/a564120.pdf?
"Demonstration of a wingless electromagnetic air vehicle"
Pretty much proof-of-concept, goes into lots more detail than I have endurance to read.
Damon:
Good grief man, this is a great find!! And an R&D activity I didn't even know was going on. Now to figure out what is conventional plasma physics and what might be extended EM-Drive physics hiding in this University of Florida paper.
Thanks again,
Best, Paul M.
...
...
What kind of hysteresis do you have in mind ? Due to the extremely high frequency (GHz) of the time-dependence of the applied electromagnetic field responsible for heating? Or due to the extremely slow (in comparison) cycling of heating and cooling due to every experiment?
....
Few surprising facts and data points for this set of hypothesis :
- That was known from beginning (and always was a difficulty for purely thermal mechanistic) : for some modes there is "no significant net thrust" without dielectric while same mode with dielectric exhibits thrust. This is known for TE012. The absence of thrust without dielectric was for "some very early evaluations", the experimental plot is not published. A TE012 mode with dielectric and thrust is reported in Brady's report.....
Consideration of the dynamic fields in the ¼ wave resonance tube shows that there is always a net Poynting vector meaning that the RF launcher tube assembly with dielectric cylinder common to both the slotted and smooth test articles is potentially a Q-thruster where the pillbox is simply a matching network.
Since the components of the electric field E parallel to a copper surface (either the wall or the bases) must be zero at the surface, the Poynting vector component perpendicular to a copper surface (either the wall or the bases) must be zero at the copper surface (either the wall or the bases) .
Let me repeat that: the Poynting vector component perpendicular to the small and the big bases of the truncated cone must be zero at those surfaces (must be zero at the small base and must be zero at the big base).
For a Transverse Magnetic (TM) mode the Poynting vector parallel to the surface doesn't have to be zero. Actually, as the images show, in some cases the maximum Poynting vector occurs at the wall for a TM mode, and for a TM mode the Poynting vector at the wall must be parallel to the wall.
On the other hand, for Transverse Electric (TE) modes both components of the Poynting vector (parallel to the wall and perpendicular to the wall) must be zero at the copper surfaces (either the wall or the bases) . For TE modes the Poynting vector is zero at all copper surfaces: zero at the walls and zero at both of the truncated cone bases.
Examination of the Poynting vector radial component shows that for this particular mode (TE012) without a dielectric, the Poynting's vector is self-cancelling and hence it is not a surprise that NASA measured no thrust force for this TE012 mode without a dielectric, since according to NASA Eagleworks' own theory (relying on Poynting's vector as per Dr. White's papers) there should not be a thrust force without a dielectric for mode TE012 because Poynting's vector self-cancels for this mode.
....
However, for other modes (TM311 for example), Poynting's vector is not self-cancelling, but it is pointed towards the small base. This justifies the fact that Shawyer communicates that he is presently not using a dielectric, since a dielectric does not appear necessary for certain modes.
Using finite element numerical method to numerical analyse the classical Maxwell equation of electric field of the idealised conical resonator, to obtain the model and practical of the distribution of the electric field of the cavity under 1000W. By analyse the properties under different modes and the different properties. Calculation show that under the four modes, TE011, TE012, TE111 and TM011, the quality factor of TE012 is highest and with highest thrust, followed by TE011. With the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End
Mulletron: I'm not too aware of the electrical properties of Galinstan and I might just be misinterpreting your wording, but if the bottom of the channel that the Galinstan is contained in is rough enough to have 'significant' height variance couldn't this cause possible issues for the cleanliness of your signal through it? A bit like using a potentiometer as a wire as the changing depth of the Galinstan would thus result in changing resistance over its length. So as your contact in the Galinstan moved across the channel, the changing resistance would add noise to it. I don't know how rough the surface is or if the noise in question is outside the realm of your tolerances, but I figured I should mention it.
Edit: It also occurs to me, that if you do want that roughness on the bottom as you mentioned, you should be able to use some filters on the rig to clean up the noise if you need to.
The Galinstan channel side walls and bottom are smooth.
A bit like using a potentiometer as a wire as the changing depth of the Galinstan would thus result in changing resistance over its length. So as your contact in the Galinstan moved across the channel, the changing resistance would add noise to it.
....
Few surprising facts and data points for this set of hypothesis :
- That was known from beginning (and always was a difficulty for purely thermal mechanistic) : for some modes there is "no significant net thrust" without dielectric while same mode with dielectric exhibits thrust. This is known for TE012. The absence of thrust without dielectric was for "some very early evaluations", the experimental plot is not published. A TE012 mode with dielectric and thrust is reported in Brady's report.....
What is new is the reporting of Poynting vector plots, to show the Poynting vector field for different modes and their significance.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352243#msg1352243
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352368#msg1352368
Although Dr. White published several papers predicting that the force on the EM Drive would depend on the Poynting vector, for example,Quote from: p.10 of Brady et.al.'s "Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum"Consideration of the dynamic fields in the ¼ wave resonance tube shows that there is always a net Poynting vector meaning that the RF launcher tube assembly with dielectric cylinder common to both the slotted and smooth test articles is potentially a Q-thruster where the pillbox is simply a matching network.
I have not seen any published calculations by Dr. White and his group of the Poynting vector field for the EM Drive. There are no Poynting vector plots shown in the paper "Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum" by Brady et.al. and there have been no Poynting vector plots shown by Paul March in our threads either.
The Poynting vector (its divergence and its vorticity) plays a prominent role in Dr. John Brandenburg's paper (see attachment to http://forum.nasaspaceflight.com/index.php?topic=36313.msg1349142#msg1349142 ) but again, there is no computation and plots of the Poynting vector field for the truncated cone for different electromagnetic modes.
Shawyer has not published any Poynting vector calculations either.
Prof. Juan Yang and her colleagues mention the Poynting vector in their calculations, but I have not seen any plots of the Poynting vector field reported in Prof. Juan Yang's papers either.
Greg Egan did not publish any plots of the Poynting vector field either, in his article: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html
Consideration of the boundary conditions for the Poynting vector seem to also have not been mentioned in the published literature of the EM Drive.
I have not seen the following previously mentioned in any EM Drive report:QuoteSince the components of the electric field E parallel to a copper surface (either the wall or the bases) must be zero at the surface, the Poynting vector component perpendicular to a copper surface (either the wall or the bases) must be zero at the copper surface (either the wall or the bases) .
Let me repeat that: the Poynting vector component perpendicular to the small and the big bases of the truncated cone must be zero at those surfaces (must be zero at the small base and must be zero at the big base).
For a Transverse Magnetic (TM) mode the Poynting vector parallel to the surface doesn't have to be zero. Actually, as the images show, in some cases the maximum Poynting vector occurs at the wall for a TM mode, and for a TM mode the Poynting vector at the wall must be parallel to the wall.
On the other hand, for Transverse Electric (TE) modes both components of the Poynting vector (parallel to the wall and perpendicular to the wall) must be zero at the copper surfaces (either the wall or the bases) . For TE modes the Poynting vector is zero at all copper surfaces: zero at the walls and zero at both of the truncated cone bases.
The following points do not appear to have been previously made either:Quote from: RodalExamination of the Poynting vector radial component shows that for this particular mode (TE012) without a dielectric, the Poynting's vector is self-cancelling and hence it is not a surprise that NASA measured no thrust force for this TE012 mode without a dielectric, since according to NASA Eagleworks' own theory (relying on Poynting's vector as per Dr. White's papers) there should not be a thrust force without a dielectric for mode TE012 because Poynting's vector self-cancels for this mode.
....
However, for other modes (TM311 for example), Poynting's vector is not self-cancelling, but it is pointed towards the small base. This justifies the fact that Shawyer communicates that he is presently not using a dielectric, since a dielectric does not appear necessary for certain modes.
Actually, Prof. Yang writes the complete opposite conclusion (http://www.emdrive.com/NWPU2010translation.pdf ):Quote from: Yang Juan,Yang Le,Zhu Yu,Ma NanUsing finite element numerical method to numerical analyse the classical Maxwell equation of electric field of the idealised conical resonator, to obtain the model and practical of the distribution of the electric field of the cavity under 1000W. By analyse the properties under different modes and the different properties. Calculation show that under the four modes, TE011, TE012, TE111 and TM011, the quality factor of TE012 is highest and with highest thrust, followed by TE011. With the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End
Prof. Juan Yang writes that her Finite Element calculations show mode TE012 as having the highest thrust (without dielectric). My exact solution calculations show that the Poynting vector fields are self cancelling for TE012 without dielectric.
Furthermore NASA Eagleworks experiments confirm the self-cancellation of the Poynting vector field for mode TE012: NASA, using the truncated cone without dielectric, and excited at the TE012 frequency, "measured NO significant net thrust": the complete opposite of Prof. Juan Yang's conclusion, but in full accordance with my calculations of the Poynting vector distribution for mode TE012.
....BTW what would be the heating profile for TE012, with and without dielectric ?.....
... it seems like you're saying is that we should discard the Poynting vector? ...
.....One should not seek a correlation between the magnetic field vector by itself and the thrust force, even in MagnetoHydroDynamics, or for the EM Drive, because the magnetic field vector oscillates like a harmonic function, hence it spends as much time going in the negative direction as the amount of time that it spends going in the positive direction. Ditto for the electric field vector by itself.
In your opinion, do you see any correlation between magnetic field strength at the large/small end as seen in the Comsol plots and the measured thrust levels?
.....
....I have not contemplated ponderomotive forces yet.
A separate question, do you think ponderomotive forces are important here?
Doctor Rodal -I don't think that this particular, specific pointed discrepancy (that mode TE012 without a dielectric resulted in no significant force in the NASA experiment and that it also has a self-cancelling Poynting vector field according to my calculations, while Prof. Juan Yang wrote in her 2010 paper that TE012 was the mode shape giving the highest thrust force without a dielectric) is due to a translation error. I also doubt that it is a typo because that statement is made in the body of the article as well as in the conclusions and it can also be ascertained from the plots shown in her 2010 paper.
Could the discrepancy between your calculations and the Chinese results be due to a typo or translation error? Given that both happen, and keeping in mind the now resolved dispute between your numbers and those of Eagleworks.
I don't think that the specific pointed discrepancy (that mode TE012 without a dielectric resulted in no significant force in the NASA experiment and that it also has a self-cancelling Poynting vector field, while Prof. Juan Yang wrote in her 2010 paper that TE012 was the mode shape giving the highest thrust force) is due to a translation error. I also doubt that it is a typo because that statement is made in the body of the article as well as in the conclusions and it can also be ascertained from the plots shown in the paper.
QuoteI don't think that the specific pointed discrepancy (that mode TE012 without a dielectric resulted in no significant force in the NASA experiment and that it also has a self-cancelling Poynting vector field, while Prof. Juan Yang wrote in her 2010 paper that TE012 was the mode shape giving the highest thrust force) is due to a translation error. I also doubt that it is a typo because that statement is made in the body of the article as well as in the conclusions and it can also be ascertained from the plots shown in the paper.
Wild speculation, then:
The Chinese, if I recollect correctly, are pumping a lot more energy into their device than Eagleworks.
I have seen repeated mention here before this results in a lot more heat, and the frequency changes with heat. So maybe this morphs TE012 into something else?
QuoteI don't think that the specific pointed discrepancy (that mode TE012 without a dielectric resulted in no significant force in the NASA experiment and that it also has a self-cancelling Poynting vector field, while Prof. Juan Yang wrote in her 2010 paper that TE012 was the mode shape giving the highest thrust force) is due to a translation error. I also doubt that it is a typo because that statement is made in the body of the article as well as in the conclusions and it can also be ascertained from the plots shown in the paper.
Wild speculation, then:
The Chinese, if I recollect correctly, are pumping a lot more energy into their device than Eagleworks.
I have seen repeated mention here before this results in a lot more heat, and the frequency changes with heat. So maybe this morphs TE012 into something else?
That's the first thing that jumps to mind, if one has to speculate. Also she uses different equations to calculate the force. Her equations also lead to another contrarian statement she makes in her 2010 paper (and in the conclusions of that paper) that keeping the small base at constant diameter and keeping the same axial length, increasing the diameter of the big base decreases the thrust. (I wonder whether she still believes those calculations as her later experiments involve truncated cones with increased -rather than decreased- cone angle of the EM Drive).
Based on what you're saying, I'm going to make another (hobbled) sense antenna, for now it will be just a solder cup. Then I will repeat the same VSWR test to see how things change.
....
So my most likely candidate for unloaded testing is 2413.5mhz. I have no clue what mode is being excited here.
....
Do Hall thrusters use Xenon or can they use a more common fuel since Xenon is rare. Massive tonnage to Mars or the Moon over time will deplete a lot of Xenon. I was thinking something like hydrogen, oxygen, or some other more common element for mass use in space.See the Electric Thruster thread. There are other options. the ELF thruster in particular can use anything. But that is where you will find them :) The answer though is yes. Ion thrusters can use stuff other than xenon.
...Have you attempted to cast the dimensions in terms of the wavelength of the drive frequency, in closed form? ...Something for me to add to "things to do when I have a chance" :)
...There are many boundary conditions. I presume you are referring here to the electric permittivity of copper, effectively assuming copper's permittivity to be Infinite so that the Electric Field E tangent to the copper surface is zero (to satisfy continuity of that vector component of E ). It looks to me the effect of impurities should be extremely small, much smaller than 0.001%, see:
In discussing the Poynting vector you rely on the ideal boundary conditions being zero at the cavity walls. To what extent do the shear forces resulting from copper being "not ideal" modify these assumptions? 0%, .001%, 1%, 10%? And how large might those left over shear forces be?
....
So my most likely candidate for unloaded testing is 2413.5mhz. I have no clue what mode is being excited here.
....
Yes you have been given a strong clue in this thread :) ( http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878 ) as to what mode is being excited here:
Mode Frequency (GHz) [Exact sltn.] Frequency (GHz) [COMSOL FEA] Poynting Vector
Cyl. TE012 2.20244 2.1794 0
Cyl.TM311 2.45835 2.4068 Towards Small Base
Cyl. TM212 2.49342 2.4575 ~ 0
Clearly this frequency ( 2.4135 GHz) falls right in the range of the calculated frequency for mode Cyl. TM311, if the dimensions of your truncated cone are within 1% of the assumed dimensions (Big Diameter=11 inches, Small Diameter=6.25 inches and Axial Length=9 inches).
It is the best mode to excite (in that frequency range) with a cavity lacking a polymer dielectric, because this mode shape (TM311) has a clear Poynting vector. The other modes have zero Poynting vectors in the longitudinal direction of the truncated cone.
As to why the measured frequency (if correct) is closer to the Finite Element Analysis (FEA) solution, here are possible reasons:
1) Internal dimensions of truncated cone may be 1% larger than the assumed internal dimensions in the exact solution analysis (Big Diameter=11 inches, Small Diameter=6.25 inches and Axial Length=9 inches).
2) Flatness of the big base and the small base. The exact solution assumes spherical section surfaces for the bases while the Finite Element solution assumes them to be perfectly flat. This can be shown to make a small difference, and its sign (increasing or decreasing the frequency) depends on the electromagnetic mode shape.
3) Internal Damping: damping decreases the frequency of the damped solution as compared to the undamped solution. The exact solution assumes infinite Q (undamped conditions).
I attach again the predicted heating profile (at the big base) for this mode (TM311) from the exact solution
....
For example, when messing around with the frustum hooked up to the SNA, it was refreshing to see how I could change the resonant frequencies at will just my applying pressure to the large end (raising the resonant freq) and then it would return to steady state when the large end rebounded. I knew I could do that, but it was neat to see it in action.
The VSWR of TM212 was all around bad, around 5.3 or so. I think I can improve it by shortening the probe. It isn't on my list of things to do unless a reason comes up later for it.
The VSWR of TM311 isn't great, but it'll do. I was able to get it down to 1.4 by really torquing down on the cable but it would go back to ~2.
There's lots of quirks I've discovered, such as just the weight of the test cable applying pressure to the frustum walls slightly changes the measured results.
....
....
For example, when messing around with the frustum hooked up to the SNA, it was refreshing to see how I could change the resonant frequencies at will just my applying pressure to the large end (raising the resonant freq) and then it would return to steady state when the large end rebounded. I knew I could do that, but it was neat to see it in action.
The VSWR of TM212 was all around bad, around 5.3 or so. I think I can improve it by shortening the probe. It isn't on my list of things to do unless a reason comes up later for it.
The VSWR of TM311 isn't great, but it'll do. I was able to get it down to 1.4 by really torquing down on the cable but it would go back to ~2.
There's lots of quirks I've discovered, such as just the weight of the test cable applying pressure to the frustum walls slightly changes the measured results.
....
@Mulletron, thanks for disclosing that information: as far as I know you are the first one reporting it, as I have not seen Shawer, Juan Yang or NASA Eagleworks disclose the above information.
Could you please provide more information on the movement of the natural frequency: when applying pressure to the large end, roughly how much did the natural frequency change? roughly from what natural frequency (without outside pressure on the big end) to what natural frequency (by pushing the big end towards the inside)?
Did you push the big end at its center? Roughly speaking how much was the displacement? would you say that it was very small, of the order of the thickness or less than the thickness of the big base plate?
Thanks :)
If I'm understanding all of these efforts correctly (please correct me if I don't!), in layman's terms, an EM drive is a conductive cavity in which most radio frequencies (RF) can propagate freely, and come out of the other end with a minimal loss of energy. But, at certain frequencies, the cavity will resonate, containing and amplifying the energy of the RF signal. For certain cavity geometries at specific frequencies, the shape (or energy?) of the resonating photons will be pointed in one direction. This directionality seems to be important for making an EM drive work. Conventional wisdom says that the energy should dissipate as heat, but instead, the energy seems to be taking the form of net thrust.
I very specifically remember being spanned on the spec anny from 700 to 2700, and when the sweeper would start over, at around 800mhz sweeper frequency, I'd see harmonics at the other end of the sweep being chased.
During this, you can even see a spike at the end:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoZWphS29nSDZkZVE&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
I was sweeping from 800-2600, and spanned from 700-2700, and there are spikes outside my sweep that max hold picked up.
So I guess that means that there are n higher order modes inside these cavities happening too.
If I'm understanding all of these efforts correctly (please correct me if I don't!), in layman's terms, an EM drive is a conductive cavity in which most radio frequencies (RF) can propagate freely, and come out of the other end with a minimal loss of energy. But, at certain frequencies, the cavity will resonate, containing and amplifying the energy of the RF signal. For certain cavity geometries at specific frequencies, the shape (or energy?) of the resonating photons will be pointed in one direction. This directionality seems to be important for making an EM drive work. Conventional wisdom says that the energy should dissipate as heat, but instead, the energy seems to be taking the form of net thrust.
If that is an accurate summary of the graphs, simulations and related discussion then I will have to disagree. A long time ago an RF engineer friend explained to me that cavities, filters and LC circuits are never dissipative. The power either goes through them or is reflected. If an RF signal with 20 MHz of bandwidth at 2085 MHz is sent through a 5 pole cavity filter with 5 MHz passband a large fraction of the RF power is simply reflected back to the amplifier. It is for this reason that isolators (circulators with a 50 Ohm load on one port) are used between the amplifier and a filter. The green on black graphs shown above, unless I am mistaken are S12 plots. Most of the power is transmitted through the cavity. More power is reflected at frequencies where there are dips in the S12 plot. This is where the reflection coefficient (SWR) is higher. Inside the cavity the Poynting vector is directed from the input port to the output port. Outside the cavity the Poynting vector is inside the dielectric of the coax; pointing away from the PA. An interesting experiment would be to decrease the length of the coax from the PA to the cavity by 2-3 cm. This will change the position of the dips in the S12 plot. Any reflected power, or return wave as it's sometimes called, will be dissipated as heat inside the amplifier.
If I'm understanding all of these efforts correctly (please correct me if I don't!), in layman's terms, an EM drive is a conductive cavity in which most radio frequencies (RF) can propagate freely, and come out of the other end with a minimal loss of energy. But, at certain frequencies, the cavity will resonate, containing and amplifying the energy of the RF signal. For certain cavity geometries at specific frequencies, the shape (or energy?) of the resonating photons will be pointed in one direction. This directionality seems to be important for making an EM drive work. Conventional wisdom says that the energy should dissipate as heat, but instead, the energy seems to be taking the form of net thrust.
If that is an accurate summary of the graphs, simulations and related discussion then I will have to disagree. A long time ago an RF engineer friend explained to me that cavities, filters and LC circuits are never dissipative. The power either goes through them or is reflected. ....
Real (as opposed to theoretical) tuned circuits always have resistive losses and some times nonlinear effects.
Real (as opposed to theoretical) tuned circuits always have resistive losses and some times nonlinear effects.
know this one has a big giggle factor but Dave Pares has updated his website again with more experimental results. It is a species of EM drive if real.
http://www.paresspacewarpresearch.org/Projet_Space_Warp/Experiment_5.htm
i know this one has a big giggle factor but Dave Pares has updated his website again with more experimental results. It is a species of EM drive if real.
http://www.paresspacewarpresearch.org/Projet_Space_Warp/Experiment_5.htm
That's all good, (I think) but how does the big end vs. small end affect the strength of the Poynting vector and hence magnitude of the force? Likely not at all on average? But the strength varies continuously so for small dx in positive direction it increases in strength but for same small dx in negative direction it decreases in strength. (Not sure I have the signs right.) But momentum is not the same even for the same electron/positron pair.If there are classical harmonic standing waves (resulting in classical resonance due to Maxwell's equations leading to a high Q) then the Poynting vector varies like Sin[ 2 ω t] /2 at twice the frequency ω of the electromagnetic fields and will average zero over a complete period of time (or multiple periods of time).
I am postulating that the strength of the fields in the axial direction is related to the geometry of the cavity in the axial direction. Or perhaps even the mode of the resonance. It seems unlikely that the strength is constant from one end to the other.
First, we may obtain some information from the simultaneous Poynting vectors as shown in Figures 5 and 6. If we consider a transverse wave causing field line oscillations, the Poynting vectors behave very differently depending on whether the wave is traveling or standing. Figure 9 is a diagram of the Poynting vectors for the two different schemes. Even though the wave amplitudes for both conditions are set to be the same and the magnitude of Poynting vector oscillations is consequently the same, the traveling wave propagates energy, while the standing wave produces no net energy flux. The Poynting vectors in Figures 5 and 6 more resemble the traveling wave pattern. Thus for the Pc3-4 wave activities in our observations the traveling wave component is stronger. We may also estimate the resonant condition by examining the phase difference between dE and dB [e.g., Singer et al., 1982]. If the phase difference is 90, the wave is standing and a resonant condition is reached.
....All the above refers to the truncated cone without the HDPE polymer dielectric segment inside it, correct?
I hooked up all the electronics and the amp to the frustum and let it run overnight and nothing failed or burst into flames, so that's good. Sadly it didn't hover or even wiggle.
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTl90eDBuMklOeTg&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
....All the above refers to the truncated cone without the HDPE polymer dielectric segment inside it, correct?
I hooked up all the electronics and the amp to the frustum and let it run overnight and nothing failed or burst into flames, so that's good. Sadly it didn't hover or even wiggle.
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTl90eDBuMklOeTg&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
....All the above refers to the truncated cone without the HDPE polymer dielectric segment inside it, correct?
I hooked up all the electronics and the amp to the frustum and let it run overnight and nothing failed or burst into flames, so that's good. Sadly it didn't hover or even wiggle.
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTl90eDBuMklOeTg&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
Yep. Empty. It wasn't on the balance. Just sitting on the floor.
....All the above refers to the truncated cone without the HDPE polymer dielectric segment inside it, correct?
I hooked up all the electronics and the amp to the frustum and let it run overnight and nothing failed or burst into flames, so that's good. Sadly it didn't hover or even wiggle.
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTl90eDBuMklOeTg&usp=sharing&tid=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM
Yep. Empty. It wasn't on the balance. Just sitting on the floor.
The entire frustum was on the floor, or just the HDPE disk? Sorry, I'm a little confused about what test you conducted. :-[
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
Have any proper scientists tested this contraption so that they can show that it doesn't work?
I found the following paper http://www-ssc.igpp.ucla.edu/personnel/russell/papers/skip_ed/node4.html, ( http://onlinelibrary.wiley.com/doi/10.1029/98JA02101/pdf ) for example, that confirms the simple result I discussed above, for standing waves:QuoteFirst, we may obtain some information from the simultaneous Poynting vectors as shown in Figures 5 and 6. If we consider a transverse wave causing field line oscillations, the Poynting vectors behave very differently depending on whether the wave is traveling or standing. Figure 9 is a diagram of the Poynting vectors for the two different schemes. Even though the wave amplitudes for both conditions are set to be the same and the magnitude of Poynting vector oscillations is consequently the same, the traveling wave propagates energy, while the standing wave produces no net energy flux. The Poynting vectors in Figures 5 and 6 more resemble the traveling wave pattern. Thus for the Pc3-4 wave activities in our observations the traveling wave component is stronger. We may also estimate the resonant condition by examining the phase difference between dE and dB [e.g., Singer et al., 1982]. If the phase difference is 90, the wave is standing and a resonant condition is reached.
TRAVELLING WAVE STANDING WAVE (EM Drive)
Poynting Vector time average is (+1/2) Poynting Vector time average is zero
(Cos[ ω t])^2 =( 1+Cos[ 2 ω t]) /2 Sin[ ω t] Cos[ ω t] = Sin[ 2 ω t] /2
(http://www-ssc.igpp.ucla.edu/personnel/russell/papers/skip_ed/fig9.gif)
So it is as simply as this: to transfer energy or momentum from virtual particles in the Quantum Vacuum, as proposed by Dr. White, a traveling wave would be needed, but then one would have no resonance, and no Q.
If one has a cavity EM Drive then resonance can take place, and hence a high Q, but that precludes the possibility of transferring energy or momentum, according to Maxwell's equations.
When the proper frequency is used, the interference of the incident wave and the reflected wave occur in such a manner that there are specific points along the medium that appear to be standing still. Because the observed wave pattern is characterized by points that appear to be standing still, the pattern is often called a standing wave pattern... These points vibrate back and forth from a positive displacement to a negative displacement; the vibrations occur at regular time intervals such that the motion of the medium is regular and repeating.
I found the following paper http://www-ssc.igpp.ucla.edu/personnel/russell/papers/skip_ed/node4.html, ( http://onlinelibrary.wiley.com/doi/10.1029/98JA02101/pdf ) for example, that confirms the simple result I discussed above, for standing waves:QuoteFirst, we may obtain some information from the simultaneous Poynting vectors as shown in Figures 5 and 6. If we consider a transverse wave causing field line oscillations, the Poynting vectors behave very differently depending on whether the wave is traveling or standing. Figure 9 is a diagram of the Poynting vectors for the two different schemes. Even though the wave amplitudes for both conditions are set to be the same and the magnitude of Poynting vector oscillations is consequently the same, the traveling wave propagates energy, while the standing wave produces no net energy flux. The Poynting vectors in Figures 5 and 6 more resemble the traveling wave pattern. Thus for the Pc3-4 wave activities in our observations the traveling wave component is stronger. We may also estimate the resonant condition by examining the phase difference between dE and dB [e.g., Singer et al., 1982]. If the phase difference is 90, the wave is standing and a resonant condition is reached.
TRAVELLING WAVE STANDING WAVE (EM Drive)
Poynting Vector time average is (+1/2) Poynting Vector time average is zero
(Cos[ ω t])^2 =( 1+Cos[ 2 ω t]) /2 Sin[ ω t] Cos[ ω t] = Sin[ 2 ω t] /2
(http://www-ssc.igpp.ucla.edu/personnel/russell/papers/skip_ed/fig9.gif)
So it is as simply as this: to transfer energy or momentum from virtual particles in the Quantum Vacuum, as proposed by Dr. White, a traveling wave would be needed, but then one would have no resonance, and no Q.
If one has a cavity EM Drive then resonance can take place, and hence a high Q, but that precludes the possibility of transferring energy or momentum, according to Maxwell's equations.
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
...so that they can show that it doesn't work
...Hi James,
Dr. Rodal, I am not an RF engineer and haven't performed math with Maxwell's equations many years. My following thoughts may have completely overlooked a fundamental issue, so please take them with the appropriate degree of skeptism. :)
Doesn't the above description (regarding the mathematical basis for the standing wave, and resulting zero time-average Poynting vector) require an ideal resonator with no losses?
...
...Hi James,
Dr. Rodal, I am not an RF engineer and haven't performed math with Maxwell's equations many years. My following thoughts may have completely overlooked a fundamental issue, so please take them with the appropriate degree of skeptism. :)
Doesn't the above description (regarding the mathematical basis for the standing wave, and resulting zero time-average Poynting vector) require an ideal resonator with no losses?
...
No, there is no requirement to have an ideal resonator with no losses, meaning an infinite Q.
The Finite Element Analysis (FEA) using COMSOL performed by NASA took into account tan delta losses to compute a finite Q. Still, COMSOL FEA solves the standard Maxwell equations, and it contains no esoteric physics whatsoever.
One can also consider a non-ideal resonator using an exact solution. One must use complex variables. The losses responsible for a finite Q are due to the imaginary part, which is responsible for the material property "loss tangent" or "tan delta".
See for example: http://web.mit.edu/22.09/ClassHandouts/Charged%20Particle%20Accel/CHAP12.PDF
Maxwell's equation mandating that the Curl of the electric field E must equal the negative of the time derivative of the magnetic field B still must be satisfied. See Equation 12.34 in the above link.
The electric permittivity describes the interaction of a material with an electric field E and is a complex quantity.
The real part of permittivity is a measure of how much energy from an external electric field is stored in a material. The imaginary part of permittivity is called the loss factor and is a measure of how dissipative or lossy a material is to an external electric field. The imaginary part of permittivity is always greater than zero and is usually much smaller than the real part. The loss factor includes the effects of both dielectric loss and conductivity.
Similarly, real materials have a magnetic susceptibility which is a complex quantity.
An analysis taking into account the complex (real and imaginary parts) of these physical properties does not change Maxwell's equations.
In order to solve differential equations one must provide boundary conditions. The thermal losses due to the induced eddy-currects in the copper are a result of the imaginary part of the material properties appearing in the solution of the boundary conditions to solve Maxwell's differential equations....Hi James,
Dr. Rodal, I am not an RF engineer and haven't performed math with Maxwell's equations many years. My following thoughts may have completely overlooked a fundamental issue, so please take them with the appropriate degree of skeptism. :)
Doesn't the above description (regarding the mathematical basis for the standing wave, and resulting zero time-average Poynting vector) require an ideal resonator with no losses?
...
No, there is no requirement to have an ideal resonator with no losses, meaning an infinite Q.
The Finite Element Analysis (FEA) using COMSOL performed by NASA took into account tan delta losses to compute a finite Q. Still, COMSOL FEA solves the standard Maxwell equations, and it contains no esoteric physics whatsoever.
One can also consider a non-ideal resonator using an exact solution. One must use complex variables. The losses responsible for a finite Q are due to the imaginary part, which is responsible for the material property "loss tangent" or "tan delta".
See for example: http://web.mit.edu/22.09/ClassHandouts/Charged%20Particle%20Accel/CHAP12.PDF
Maxwell's equation mandating that the Curl of the electric field E must equal the negative of the time derivative of the magnetic field B still must be satisfied. See Equation 12.34 in the above link.
The electric permittivity describes the interaction of a material with an electric field E and is a complex quantity.
The real part of permittivity is a measure of how much energy from an external electric field is stored in a material. The imaginary part of permittivity is called the loss factor and is a measure of how dissipative or lossy a material is to an external electric field. The imaginary part of permittivity is always greater than zero and is usually much smaller than the real part. The loss factor includes the effects of both dielectric loss and conductivity.
Similarly, real materials have a magnetic susceptibility which is a complex quantity.
An analysis taking into account the complex (real and imaginary parts) of these physical properties does not change Maxwell's equations.
Which part of Maxwell's equations account for the observed thermal losses due to the induced currents in the frustum's large base?
BIG CORRECTION
It has bothered me that, if the Poynting vector (http://en.wikipedia.org/wiki/Poynting_vector)(ExB) would be a quadratic function of the harmonic function so that it never changes sign and therefore does not change orientation with time, even for an AC field, as for example discussed in http://en.wikipedia.org/wiki/Poynting_vector#Time-averaged_Poynting_vector, then the operation of the EM Drive would not be a subject of so much controversy.
For the Poynting vector to vary like (Cos[ ω t + phaseAngle])^2 one needs that the E and B fields to be in phase with each other, as shown in the following image for example:
(http://www.blazelabs.com/pics/empropagation2.gif)
But then it dawned on me, that the E and B fields cannot be in-phase with each other (therefore the above image is only true for a travelling wave and it is inappropriate for an EM Drive cavity which instead has standing waves), because Maxwell's equation states that they must 90 degrees out of phase with each other:
One of Maxwell's equations (http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction#Maxwell.E2.80.93Faraday_equation) states that:
Curl E = - d B / dt
so, for example if the magnetic field B varies as Cos[ ω t], then the electric field must vary as its time derivative:
- d(Cos[ ω t])/dt = ω Sin[ ω t] , and therefore the Poynting vector ExB should vary as
Sin[ ω t] Cos[ ω t] = Sin[ 2 ω t] /2, which oscillates at twice the frequency of the electromagnetic fields and has a time average value of zero.
Since the Poynting vector has a time average of zero, there cannot be any net energy flow out of the EM Drive.
This is due to the fact that the waves inside the EM Drive are standing waves. Therefore the Poynting vector is just describing how energy is transferred between the electric and magnetic fields.
Also this means that there cannot be momentum outflow either, due to the Poynting vector, if the electromagnetic fields are harmonic functions of time.
Imagine, for discussion's sake, that it could indeed be possible that virtual electron-positron pairs would materialize out of the Quantum Vacuum, and that when such a pair materializes the Poynting vector is pointing towards the big base of the truncated cone EM Drive. Then the electron-positron pair would be transported by the Poynting vector field towards the big base of the truncated cone, and shortly during that transport the electron-positron would cease to exist, returning back to the vacuum. Then (as shown by Einstein himself in a though-model he proposed a long time ago concerning light particles being transported within a friction-less railroad car) the truncated cone would experience a recoil -simultaneous with the transport of the electron-positron pair-, which would result in a net force towards the small base of the truncated cone. If the Poynting vector would always be pointing towards the big base, this would function as proposed by Dr. White.
Unfortunately, the standing waves within an EM Drive cavity are such that the E and B fields must be 90 degrees out of phase with each other (due to Maxwell's equations), and this dictates that the Poynting vector is changing direction at a frequency twice as high as the frequency of the electromagnetic fields. Therefore, if electron-positron pairs would materialize such as in the thought-model discussed above resulting in a recoil of the EM Drive towards the small base, it would occur just as often that electron-positron pairs would be transported in the completely opposite direction and the EM Drive would experience a force in the opposite direction. Therefore what would be expected (out of the Quantum Vacuum model) is to have forces in the EM Drive pointing towards the small base just as often as having forces pointed in the opposite direction towards the big base, and this would result in no net transport of the EM Drive over a period of such oscillations.
I will need to correct some of my previous postings concerning the Poynting vector for the EM Drive: for a cavity like the EM Drive, the Poynting vector oscillates with time as Sin[ 2 ω t] /2: therefore the time average of the Poynting vector must be zero.
This article in Wikipedia does not apply to a resonating cavity like the EM Drive:
http://en.wikipedia.org/wiki/Poynting_vector#Time-averaged_Poynting_vector
because it does not obey Maxwell's equation Curl E = - d B / dt which must be obeyed for a resonating cavity.
...
My current thoughts still hinge on the evanescent waves through the gaps in the structure as being key to the operation of this device. That is, evanescent waves are unidirectional, they do not average to zero but do collapse to zero at some distance from the cavity. This distance is considerably greater than one third or even one full wavelength.
My current thought is that perhaps, as the evanescent waves pass through the gaps, they apply force to the virtual particles in one direction only and then collapse as we know they do. However, the virtual particles have already dissipated back into the QV so only the momentum of the cavity remains.
I hope to run some cases testing this in the near future but a Mathematica model would be much more desirable, and telling, than a Meep test result. Fortunately, Meep does provide a QV model in 2-D - it was prepared in order to measure Casimir forces but should be useful for our situation, too. Unfortunately, only 1-D and 2-D models were implemented. Once I figure out how to run the model, and what it means, I will be ready to attempt some results.
In order to solve differential equations one must provide boundary conditions. The thermal losses due to the induced eddy-currects in the copper are a result of the imaginary part of the material properties appearing in the solution of the boundary conditions to solve Maxwell's differential equations....Hi James,
Dr. Rodal, I am not an RF engineer and haven't performed math with Maxwell's equations many years. My following thoughts may have completely overlooked a fundamental issue, so please take them with the appropriate degree of skeptism. :)
Doesn't the above description (regarding the mathematical basis for the standing wave, and resulting zero time-average Poynting vector) require an ideal resonator with no losses?
...
No, there is no requirement to have an ideal resonator with no losses, meaning an infinite Q.
The Finite Element Analysis (FEA) using COMSOL performed by NASA took into account tan delta losses to compute a finite Q. Still, COMSOL FEA solves the standard Maxwell equations, and it contains no esoteric physics whatsoever.
One can also consider a non-ideal resonator using an exact solution. One must use complex variables. The losses responsible for a finite Q are due to the imaginary part, which is responsible for the material property "loss tangent" or "tan delta".
See for example: http://web.mit.edu/22.09/ClassHandouts/Charged%20Particle%20Accel/CHAP12.PDF
Maxwell's equation mandating that the Curl of the electric field E must equal the negative of the time derivative of the magnetic field B still must be satisfied. See Equation 12.34 in the above link.
The electric permittivity describes the interaction of a material with an electric field E and is a complex quantity.
The real part of permittivity is a measure of how much energy from an external electric field is stored in a material. The imaginary part of permittivity is called the loss factor and is a measure of how dissipative or lossy a material is to an external electric field. The imaginary part of permittivity is always greater than zero and is usually much smaller than the real part. The loss factor includes the effects of both dielectric loss and conductivity.
Similarly, real materials have a magnetic susceptibility which is a complex quantity.
An analysis taking into account the complex (real and imaginary parts) of these physical properties does not change Maxwell's equations.
Which part of Maxwell's equations account for the observed thermal losses due to the induced currents in the frustum's large base?
That is how COMSOL's Finite Element Analysis provided the solution for the thermal losses and the predicted temperature for NASA's EM Drive truncated cone.
The frequencies obtained by COMSOL's FEA were obtained by solving an eigenvalue problem.
Damping is responsible for the finite amplitude of the response, but the presence of damping does not preclude standing waves, waves which have fixed nodes and anti-nodes. The boundary conditions due to the end plates do not disappear due to heat production. For example, one of the boundary conditions is that the tangent electric field must be continuous at the material interface. This boundary condition (and therefore the node produced in that component of the electric field) does not cease to exist due to heat generation. That only affects the amplitude. The only way to remove that boundary condition would be to remove the end plate, and if you would do that, the EM Drive would no longer be a completely enclosed cavity.
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:
http://amasci.com/weird/vindac.html
http://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.html
http://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.html
Quote...so that they can show that it doesn't work
Just curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.
There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:
http://amasci.com/weird/vindac.html
http://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.html
http://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.html
Every previous world changing idea didn't try to violate a founding principal of all physics, namely CoE and CoM.QuoteQuote...so that they can show that it doesn't work
Just curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.
There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.
I'm still waiting for an actual test of the operation of this craft. There haven't been any non-faulty experiments done yet that actually show it producing any thrust. Namely it must be tested in a vacuum. I don't try to merge philosophy and science and currently this "EM Drive" is purely in the realm of philosophy with no actual data yet. Thus I dismiss it just like the people claiming they made an anti-gravity drive in their garage.
It's rather insulting that this forum topic even exists here.
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:
http://amasci.com/weird/vindac.html
http://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.html
http://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.html
Every previous world changing idea didn't try to violate a founding principal of all physics, namely CoE and CoM.QuoteQuote...so that they can show that it doesn't work
Just curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.
There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.
I'm still waiting for an actual test of the operation of this craft. There haven't been any non-faulty experiments done yet that actually show it producing any thrust. Namely it must be tested in a vacuum. I don't try to merge philosophy and science and currently this "EM Drive" is purely in the realm of philosophy with no actual data yet. Thus I dismiss it just like the people claiming they made an anti-gravity drive in their garage.
It's rather insulting that this forum topic even exists here.
Problem is no one is going to give that kind of money unless they are proved to work at the level they are now.
James, thank you for the interesting, thought-provoking discussion. :)
You accurately and completely answered the questions I asked. Unfortunately, I didn't ask my questions very well. :)
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1354235#msg1354235
A constant-amplitude standing wave does indeed result in a zero time-average Poynting vector. However, I am questioning your conclusion that a constant-amplitude standing wave accurately represents a real resonator cavity such as the as-tested EM drive frustum. Instead, I would expect a decaying amplitude standing wave to be a more accurate model/plot (as would be derived from a full solution to Maxwell's equations with proper boundary conditions such as non-zero resistance, etc).
Once a time-decaying standing wave is used for computation of a time-average Poynting vector, I'm having trouble seeing how the incident and reflected energy can perfectly cancel and become zero. I'll readily admit I may be oversimplifying and/or missing a fundamental concept; it's been a long time since I actually computed time constants for resonant cavities using Maxwell's equations and non-zero resistances.
Phrased a bit differently, I believe only excited modes with current/thermal losses in the base plates will significantly weight the direction of the time-average Poynting vector. Each pair of incident/reflected waves would have a larger energy loss at the base plate with the excited E field (and therefore excited currents) than the energy loss at the opposing base plate. For modes with near-zero E fields at the base plate boundaries, each incident/reflected wave pair would have a near equal energy delta regardless of which base plate they came in contact with; the resulting time-averaged direction would be random and magnitude limited by the energy lost in the very first reflection (randomly either the large or small base, with a magnitude very close to zero).
I view this Poynting vector discussion to be completely independent of whether Dr. White's QV interactions, or some other classical physics can explain the EM drive anomalous thrust. Just wanted to chime in on a what appeared to be the use of a constant-amplitude standing wave to describe a real-world system. Your earlier observation of a non-zero time averaged Poynting vector seemed like a reasonable statement given that only excited modes with current/thermal losses in the base plates would quickly diverge from the simplified constant-amplitude standing wave model.
Regards,
James
I agree with Mulletron that the answer to Paul March's question is that it is much more effective to have a distributed power spectral density than the power concentrated at a single frequency spike. When the natural frequency changes in an unpredictable manner, it is much more effective to have a distributed power spectral density of excitation (it is the power spectral density ( http://en.wikipedia.org/wiki/Spectral_density#Power_spectral_density ) over the spectrum of changing natural frequencies that matters).Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
...
...
This is evident from the very low Q's reported by NASA (7K to 22K) compared with the Chinese, who report a Q=117K :Quote from: Juan Yangthe resonant frequency and quality factor of the independent microwave resonator system are 2.44895 GHz and 117495.08 respectively...
NASA's reported Q for the vacuum experiment is a meager Q = 6726, which is 17 times smaller than the Chinese reported Q = 117495.
...
A long time ago an RF engineer friend explained to me that cavities, filters and LC circuits are never dissipative. The power either goes through them or is reflected. If an RF signal with 20 MHz of bandwidth at 2085 MHz is sent through a 5 pole cavity filter with 5 MHz passband a large fraction of the RF power is simply reflected back to the amplifier.
Note here that we are choosing to work with the
momentum density associated with the canonical energy
momentum tensor rather than the Poynting vector; the
latter is expected to integrate to zero [9]
Further,
they should be arranged so that the resulting tetrahe-
dron (with the four particles placed at the vertices) has
no parity symmetry so that the vacuum photons get to
see a chiral structure. If these conditions are fulfilled
then a non-zero momentum develops which scales as the
fourteenth inverse power of the length scale of the tetra-
hedron.
Structure of polyethylene consists of directed tetrahedral configuration of sp3 hybridized carbon bonds along repeat structure with no free valence electrons.http://plastics.tamu.edu/class-resources/semi-conducting_polymers
From the letter linked to below:QuoteNote here that we are choosing to work with the
momentum density associated with the canonical energy
momentum tensor rather than the Poynting vector; the
latter is expected to integrate to zero [9]QuoteFurther,
they should be arranged so that the resulting tetrahe-
dron (with the four particles placed at the vertices) has
no parity symmetry so that the vacuum photons get to
see a chiral structure. If these conditions are fulfilled
then a non-zero momentum develops which scales as the
fourteenth inverse power of the length scale of the tetra-
hedron.
http://arxiv.org/pdf/1011.4376.pdf
http://iopscience.iop.org/0295-5075/93/4/41002/fulltext/epl_93_4_41002.html
Don't think I've linked to this one before.QuoteStructure of polyethylene consists of directed tetrahedral configuration of sp3 hybridized carbon bonds along repeat structure with no free valence electrons.http://plastics.tamu.edu/class-resources/semi-conducting_polymers
It is shown that the first non-trivial contribution of the momentum transfer to the object from the radiation field occurs at fourth order in the Born series.The fourth order terms are usually neglected in most treatises ! Actually, sometimes the second order Born terms are taken into account (for example in http://en.wikipedia.org/wiki/Grazing-incidence_small-angle_scattering ), but I don't know of applications that have used the 3rd order term and much less the 4th order term.
One should also note that for purely dielectric scatterers, the momentum is expected to vanish as the electromagnetic momentum density coincides with the Poynting vector.
So perhaps the only experimenters that have found something along these lines is NASA Eagleworks due to Paul March trying the PTFE and HDPE dielectric polymer inserts, and without them there is really no thrust (one of the very interesting things disclosed by Paul March is that Neoprene Rubber gave negligible thrust force). This would mean that the experimental forces measured by Shawyer and Juan Yang in China for EM Drives (using much higher power input) without thermoplastic inserts maybe just thermal effect artifacts.
EDIT 2: It the authors are correct and one needs to take into account nonlinearity + anisotropy to get momentum from the quantum vacuum, this is much more complicated stuff than what Dr. White or Dr. Woodward have been considering. It will be much more difficult to prove or disprove ....There are non-uniqueness issues associated with an inverse nonlinear problem, and many other complications...There is no unique canonical correction to the energy-stress tensor, there are several and it is not clear which one is right for the problem....
Lastly, like any busy lab, Eagleworks could always use extra funding to deal with its daily heart burns and required salaries to keep it going. However we are currently a NASA sponsored facility, which sadly precludes being able to accept crowd sourcing or any other outside source of funding, unless it's through a commercial NASA Space Act Agreement that has to be approved up through NASA headquarters in Washington DC.
They can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.So would it be possible to give you some contribution in kind? If so, what do you need?
Carl White, asked this interesting question (http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=2949&p=120754#p120743):QuoteThey can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.So would it be possible to give you some contribution in kind? If so, what do you need?
Carl White, asked this interesting question (http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=2949&p=120754#p120743):QuoteThey can't accept dollars, but can they still accept donations of equipment? What about equipment "sold" to them for $1? Could provide some RF amplifiers for example.So would it be possible to give you some contribution in kind? If so, what do you need?
In general, government regs forbidding accepting gifts include "or value" precisely to avoid that loophole.¹ So equipment, whether donated or "sold" for $1, is still a donation of value. IIRC, even volunteering your own labour is forbidden unless specifically authorised.
It's the same with NASA's unused facilities. NASA can't donate time to a private company, even if the facility (or staff!) would otherwise go unused, because they are required to charge "full equivalent commercial rates" or similar wording. The only exemption is if NASA and the private user "exchange services of equivalent value" via an SAA. NASA has been interpreting "equivalent value" as the private user letting NASA researchers play with their toys, which Congress has cracked down on recently.
That said, an exemption for crowd-sourced donations makes sense. Similarly, a Patreon type system where amazing people sponsor their favourite research project via a small monthly amount. It may be something worth lobbying for. Even if it is just a pro-forma authorisation for agency officials to be able to use SAA's for specific crowd-sourcing efforts. Unfortunately, SAA's have been tightened even further by Congress.
¹ For example, if I pay the tuition fees for the children of a government official to go to a private-school/top-university, or give them a free car/house/cheap-loan, etc, it's still bribery even though there was no cash-in-hand.
LENRProbably beyond the speculation tolerance of NSF :( Does no proven power source (e.g. SEP, but even nuclear) make for a propulsion system that's competitive enough with existing and more conventional propulsion schemes, for short term applications?
we have to continually tell management the value proposition for why they should fund our research, [...] once we get our hands around the physics they are using.Utter revolution is accessory as a very short term goal; but probably inevitable anyway, if EM propulsion took off.
IMHO, only a very high power experiment producing a very high thrust (above a newton and more), and if possible even lift-off, where air flow circulation around the cavity could not account for the enormous thrust measured by equipment and observed with our own eyes, will settle the case. And will open the colonization of our solar system.
Dr. Rodal:
I think that the reason why the Neoprean rubber didn't generate any detectable thrust with the ~30W of available power was that it's carbon loaded which increases its RF loss tangent from that of HDPE or PTFE (~0.0004) up to 0.02 which really loads down the net E-field generated in the cavity for a given input power. And since we think that the thrust effect we are observing is proportional to E-field squared (E^2) that could make a huge difference in performance.
Now please note that I concur with your analysis on the E&M Poynting vector time averaging to zero in the frustums. For example when the Cannae pillbox cavity's input RF power feed is well Z-matched with a VSWR= ~1.00, the RF Poynting power flow into the cavity is always towards the large OD pancake section of the cavity. If one envisions the quantum vacuum (Q-V) as a semi-virtual electrical plasma as Dr. White does, that would imply that the Poynting power flow vector would entrain the Q-V plasma and send it on its way toward the pillbox end of the cavity and then out of the cavity, the back-reaction on the cavity should be in the opposite direction towards the RF feed end of the Cannae test article, but the observed thrust vector is opposite to that surmise, i.e. toward the shorter RF sense antenna end of the cavity per the attached slide.
Now Per the newly authored Q-V plasma simulation code that Dr. White just finished, the equal bidirectional Q-V plasma flow for the Cannae cavity comes from the high-Q pancake section with a Q of ~9,000 for the un-slotted version of the cavity. However due to the high E-field region created n the throat of the RF feed, this cylindrically shaped high E-field volume acts as an obstruction to the Q-V plasma flow. This E-field obstruction created in the PTFE cylinder then accelerates the Q-V plasma around it in a Bernoulli like effect that accelerates the Q-V plasma flow coming from the main pillbox cavity. This unbalanced and accelerated Q-V plasma flow that goes away from the large pill box cavity in the direction of the RF input section is what generates the NET thrust in our model.
Next, using this new Q-V plasma simulation tool that utilizes the instantaneous E&M fields from COMSOL for one complete RF cycle in 5 degree increments as its input file, we are now seeing why we need the PTFE or HDPE dielectrics in the frustum while using near pure sine wave power levels below ~100W in the ~2.0 GHz frequency range to generate detectable thrust, and why Shawyer and the Chinese didn't while pumping 80W to 2,500W using magnetron RF sources. We think the reasons are two fold.
The first is that Shawyer and the Chinese both used magnetron RF sources for their experiments. An RF source that generates large AM, FM and PM modulation of the carrier wave with typical FM modulation bandwidth on the order of at least +/-20 MHz. (These time rate to change of energy modulations increase the Q-V density in our model.)
The second reason we found running these 3D Q-V plasma simulations for the EMPTY copper frustum, was that increasing the input power tends to focus the Q-V plasma flow from near omnidirectional from the frustum at low powers, to a much more jet like beam at higher powers measured in kW to tens of kW-rf. In fact the simulation for the 100W run predicted only ~50uN for our pure RF system with dielectric, while the 10kW run predicted a thrust level of ~6.0 Newton without a dielectric in the cavity. And at 100kW-rf it was now up to ~1300 Newton, but the input power to thrust production nonlinearity was starting to taper off around 50kW. Of course these Q-V plasma thrust predictions are based on the Q-V not being immutable and non-degradable, a feature we admit is not widely accepted by the mainstream physics community, at least at the moment. :)
Lastly, due to the above non-linear thrust scaling with input power predictions, we have started the build up of a 100W-to-1,200W waveguide magnetron RF power system that will drive one of our aluminum RF frustum cavities. Initially the test rig will follow Shawyer's first generation test rig that used a tetter-totter balance system in air only to see if we can generate similar thrust levels that Shawyer reported using a hermetic sealed box, which were in the ~16 to 300 milli-Newton range dependent on the Q-Factor of the frustum.
BTW, the reason we included the "what-if" Eagleworks can make this thing work solar system trajectory section on our 2014 JPC paper was that we have to continually tell management the value proposition for why they should fund our research, much in the same way we have to convince Chris Bergin here at NSF we really will be talking about space applications for these Q-Thruster like devices, once we get our hands around the physics they are using. However when we do, the solar system and beyond will be ours for the picking...
Best, Paul M.
If a cubesat experiment in space cannot be done (due to insufficient funding for now), very high power experiments (10-100 kW) in ambient air are the only way to go, to prove the EmDrive does work as expected:
- Shawyer experiments in ambient air (as well as newer superconducting designs) are now kept under a shroud of secrecy.
- Chinese mid-to-high power experimental results (~ 2000 W) in ambient air are on the contrary regularly published in academic journals, but are still uncertain because Pr. Juan Yang is not able to share additional data, and spurious causes like air currents are not ruled-out.
- Eagleworks ruled-out the possibility of ambient air currents, running the experiments in a hard vacuum. But because the setup needs to be compact and light enough to sit into the vacuum chamber and hang on the sensitive torsion pendulum (power source included), the amp had to be very weak (10 to 30 watts only) and moreover leaked/sparked in that lower pressure environment. Hence, sadly, less than a hundred micronewtons of thrust. Because of the tiny thrust signatures just above the seismic noise, the results published so far created more questions about other possible spurious causes (EM interaction with the torsion pendulum, the walls of the chamber…).
IMHO, only a very high power experiment producing a very high thrust (above a newton and more), and if possible even lift-off, where air flow circulation around the cavity could not account for the enormous thrust measured by equipment and observed with our own eyes, will settle the case. And will open the colonization of our solar system.
Just as an aside why have Shawyer's experiments dropped off the radar?
To have confidence on numerical results one should start by comparing the results with known solutions for (at least) simpler cases. (Particularly for a numerical method, like the Finite Difference Method used in MEEP, that as we have discussed before one can not be assured to converge to a solution? )
For example, I compared my exact solutions, and they were within 1% or so of COMSOL FEA results for NASA's truncated cone and their experimental results.
Thanks for that informative response. I do wonder if we will hear anything from him at all then for the foreseeable future.:(Just as an aside why have Shawyer's experiments dropped off the radar?
I don't know. I could think of two different possibilities:
- Either the latest superconducting tests are not positive at all, and contrary to Shawyer's expectation, the thrust does not dramatically improve with the Q factor of the cavity. The EmDrive, at least here on earth, would then be a dead-end.
- Or the exact opposite and Shawyer, who runs a private company (SPR Ltd) and filed various patents on the EmDrive, has now signed a contract with one or several big private aerospace companies for the development of new advanced propulsion systems based on the EmDrive technology, and does not want/is forbidden to disclose any information, maybe (more exactly surely if it's the case) because this information is protected under NDA.
All he accepted to answer me when I asked him about the precise dimensions of the Chinese frustum, is that for a number of years, SPR Ltd policy has been to provide worldwide support to universities and national research agencies (including NASA), for who they checked out their EmDrive cavity geometry using the design software SPR Ltd has developed in-house, because he claims commercial finite element software does not give accurate enough results for engineering purposes. But now we must understand the information that has been disclosed to him by the Chinese cannot be passed on to a third party.
Quoting Dr. RodalQuoteTo have confidence on numerical results one should start by comparing the results with known solutions for (at least) simpler cases. (Particularly for a numerical method, like the Finite Difference Method used in MEEP, that as we have discussed before one can not be assured to converge to a solution? )
For example, I compared my exact solutions, and they were within 1% or so of COMSOL FEA results for NASA's truncated cone and their experimental results.
Since we are interested in forces, Meep's ability to accurately calculate resonance frequency doesn't enter into the question. (I am provided with the cavity dimensions and drive frequencies, thereby avoiding that question.)
I have calculated a simple case to verify forces and achieved results within 1% of the known values. That is, Meep calculates the radiant force of a plane wave striking an absorbing surface in vacuum as -1.0006645812/c which is well within 1% of 1/c, the exact answer. Further, Meep calculates the radiant force of a plane wave striking a perfectly reflecting surface in vacuum as -2.0295743306/c which is within 1.5% of 2/c, the exact answer.
In these cases, the positive direction is from the detector to the source, so the minus sign is correct.
Oh Paul... propellantless thrusters have already so many detractors and skeptics... and you mentioned a LERN power source for them?
aside the LERN part, your posts are awesome as always.
Dr. Rodal:
I think that the reason why the Neoprean rubber didn't generate any detectable thrust with the ~30W of available power was that it's carbon loaded which increases its RF loss tangent from that of HDPE or PTFE (~0.0004) up to 0.02 which really loads down the net E-field generated in the cavity for a given input power. And since we think that the thrust effect we are observing is proportional to E-field squared (E^2) that could make a huge difference in performance.
Now please note that I concur with your analysis on the E&M Poynting vector time averaging to zero in the frustums. For example when the Cannae pillbox cavity's input RF power feed is well Z-matched with a VSWR= ~1.00, the RF Poynting power flow into the cavity is always towards the large OD pancake section of the cavity. If one envisions the quantum vacuum (Q-V) as a semi-virtual electrical plasma as Dr. White does, that would imply that the Poynting power flow vector would entrain the Q-V plasma and send it on its way toward the pillbox end of the cavity and then out of the cavity, the back-reaction on the cavity should be in the opposite direction towards the RF feed end of the Cannae test article, but the observed thrust vector is opposite to that surmise, i.e. toward the shorter RF sense antenna end of the cavity per the attached slide.
Now Per the newly authored Q-V plasma simulation code that Dr. White just finished, the equal bidirectional Q-V plasma flow for the Cannae cavity comes from the high-Q pancake section with a Q of ~9,000 for the un-slotted version of the cavity. However due to the high E-field region created n the throat of the RF feed, this cylindrically shaped high E-field volume acts as an obstruction to the Q-V plasma flow. This E-field obstruction created in the PTFE cylinder then accelerates the Q-V plasma around it in a Bernoulli like effect that accelerates the Q-V plasma flow coming from the main pillbox cavity. This unbalanced and accelerated Q-V plasma flow that goes away from the large pill box cavity in the direction of the RF input section is what generates the NET thrust in our model.
Next, using this new Q-V plasma simulation tool that utilizes the instantaneous E&M fields from COMSOL for one complete RF cycle in 5 degree increments as its input file, we are now seeing why we need the PTFE or HDPE dielectrics in the frustum while using near pure sine wave power levels below ~100W in the ~2.0 GHz frequency range to generate detectable thrust, and why Shawyer and the Chinese didn't while pumping 80W to 2,500W using magnetron RF sources. We think the reasons are two fold.
The first is that Shawyer and the Chinese both used magnetron RF sources for their experiments. An RF source that generates large AM, FM and PM modulation of the carrier wave with typical FM modulation bandwidth on the order of at least +/-20 MHz. (These time rate to change of energy modulations increase the Q-V density in our model.)
The second reason we found running these 3D Q-V plasma simulations for the EMPTY copper frustum, was that increasing the input power tends to focus the Q-V plasma flow from near omnidirectional from the frustum at low powers, to a much more jet like beam at higher powers measured in kW to tens of kW-rf. In fact the simulation for the 100W run predicted only ~50uN for our pure RF system with dielectric, while the 10kW run predicted a thrust level of ~6.0 Newton without a dielectric in the cavity. And at 100kW-rf it was now up to ~1300 Newton, but the input power to thrust production nonlinearity was starting to taper off around 50kW. Of course these Q-V plasma thrust predictions are based on the Q-V not being immutable and non-degradable, a feature we admit is not widely accepted by the mainstream physics community, at least at the moment. :)
Lastly, due to the above non-linear thrust scaling with input power predictions, we have started the build up of a 100W-to-1,200W waveguide magnetron RF power system that will drive one of our aluminum RF frustum cavities. Initially the test rig will follow Shawyer's first generation test rig that used a tetter-totter balance system in air only to see if we can generate similar thrust levels that Shawyer reported using a hermetic sealed box, which were in the ~16 to 300 milli-Newton range dependent on the Q-Factor of the frustum.
BTW, the reason we included the "what-if" Eagleworks can make this thing work solar system trajectory section on our 2014 JPC paper was that we have to continually tell management the value proposition for why they should fund our research, much in the same way we have to convince Chris Bergin here at NSF we really will be talking about space applications for these Q-Thruster like devices, once we get our hands around the physics they are using. However when we do, the solar system and beyond will be ours for the picking...
Best, Paul M.
Fantastic post, Paul. We are so lucky that you are still working on this project and that you are reporting this information. We hope that this project, as you outlined it, gets full funding.
I also love your scientific objectivity, for example, concerning that Dr. White's simulations do not appear to abide by the assumption that the Quantum Vacuum should be indestructible and immutable. One reason that the mainstream physics community assumes the Quantum Vacuum is indestructible and immutable is because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.
Godspeed ahead :)
Oh Paul... propellantless thrusters have already so many detractors and skeptics... and you mentioned a LERN power source for them?
aside the LERN part, your posts are awesome as always.
Aces-High:
I don't work directly with LENR R&D, so my sources are all second hand on this topic by nature, but from what've I've been told by very mainstream sources in the field that cold fusion, AKA LENR, can not be and should not be discounted in the mid to long term. Past that I won't mention it again in this venue.
In the meantime if we discount closed cycle nuclear fission for a space power source due to political issues, all that is left is H2 & CH4 fuel cells and/or solar photovoltaic arrays up to about 300kWe for sure, and maybe pushed up to 500kWe at Earth orbit, but no more for some time to come. Lets hope that power range is sufficient for the needs of the first generation of exotic thrusters like the EM-Drive and its other brethren.
Best, Paul M.
In the meantime if we discount closed cycle nuclear fission for a space power source due to political issues, all that is left is H2 & CH4 fuel cells and/or solar photovoltaic arrays up to about 300kWe for sure, and maybe pushed up to 500kWe at Earth orbit, but no more for some time to come. Lets hope that power range is sufficient for the needs of the first generation of exotic thrusters like the EM-Drive and its other brethren.
Best, Paul M.
LENRProbably beyond the speculation tolerance of NSF :( ...
LENRProbably beyond the speculation tolerance of NSF :( ...
I think Paul's observation is apropos and quite relevant to space flight applications, and should be within the speculation tolerance of NSF. NASA has a long history of researching LENR even to the point of experimentation and prototypes. Multiple well-known universities in the U.S. currently have fully-funded LENR research programs. A well-known Japanese university just funded a LENR research program along with some industry giants from that country. Airbus has a keen interest and research program in LENR. Boeing--same. Rest assured, many if not most governmental and private entities with an interest in space flight have active LENR research programs. All of which ironically makes LENR seem less speculative in a sense than the EM Drive itself.
Midterm is 5 to ten years? (LM says they're going to knock it out in that timeframe.) That's not my definition of medium to long term. :) That's short term to me. Short term as in: "OMG! We're late designing a hull to put it in already."
if you are counting on LERN mid and long term... why not count on hot fusion at the mid and long term as a power source for EM-Drive? Polywell, General Fusion, Skunkworks, etc.
All are mid to long term, should be light and compact enough to be used on spacecraft, are more engineering problems than physics problems (I mean, we KNOW fusion happens, we know how to make it happen, we just are trying to win over problems like how to get more output power than input power and similar hurdles).
LERN on the other hand has not even be proved to be real yet nor there are valid and accepted theories for why it should happen.
Therefore, it would be much more elegant to include in any EM Thruster paper, hot compact fusion as a power source... more like a "make your bet on WHICH fusion proposal will work and have the specs we need"...
Aces High:
The hot fusion candidates you mentioned all have one major problem. That being that except for D-T fusion, no hot fusion scheme to date has ever demonstrated breakeven let alone enough energy gain over its input to make it a viable aerospace fusion reactor candidate. (I believe that the UK D-T fusion reactor may have reached breakeven for a few minute run, but Lord, look at the neutron flux it generates, which is ~70% of a pure fission reactor for a given output power, a pure fission reactor that can be much smaller and lighter than any tokomak reactor can ever be.) And after seeing what happened during the poly-well fusion reactor saga, I have great doubts as to the claims by any of the current crop of alternate fusion reactor concepts, L-M's optimistic claims about their fusion reactor design concept not withstanding.
Best, Paul M.
Crazy, possibly stupid question;It has been tried and it was successful. Even aneutronic fusion reactions have been achieved with lasers in 2005 (http://fire.pppl.gov/fusion_lasers_nature_082605.pdf). But how do you extract energy, and how much if you can? As Paul said, the problem is not producing fusion reactions, because we already do know how. It's extracting more power than what has been injected into the reactor to produce those fusion reactions. This is the concept of break-even applied to nuclear fusion. Wikipedia (http://en.wikipedia.org/wiki/Break-even) has a good explanation of the concept.
Has anyone ever considered a more direct approace to fusion? Instead of trying to heat a Deuterium / Tritium mix, why not do a set directed streams of high velocity Tritium into a target point, using the equivelent of a particle accelerator? There has been success at single atom streams at cryogenic tempertures for directing streams of atoms, but I've never read anywhere that anyone has tried this approach.
Start a new thread.. try to make it space relevant.What QuantumG said. I'm sorry for being part of the digression. Let's focus on the EmDrive and its space-related flight applications.
If a numerical model cannot get the electromagnetic fields correctly for the EM Drive in that simpler case, one cannot derive from such a model valid conclusions on the importance of "the openings are to the overall operation of the drive" or to the validity of forces that are based on derivatives of the fields.Modeling a plane wave striking an absorbing surface is a different problem than modeling the standing waves in a resonating cavity like the EM Drive.
I was referring to images like these ones, that you posted some time ago:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=705861;image)
The electromagnetic fields in that image don't look like the electromagnetic fields in the EM Drive, indicating that there was something wrong with your model of the EM Drive. Since electromagnetic forces are due to the electromagnetic fields, if one doesn't get the electromagnetic fields correctly, then it stands to reason that the calculations of electromagnetic forces in the EM Drive cannot be correct either.
Wasn't that particular simulation modeling the EM Drive without openings, which in turn showed us how important the openings are to the overall operation of the drive (at least in the simulation)?
I had asked (at a time that I didn't know that this was a 2D instead of a 3D model) whether the figure represented a component of (or the norm of) the electric or the magnetic field.If a numerical model cannot get the electromagnetic fields correctly for the EM Drive in that simpler case, one cannot derive from such a model valid conclusions on the importance of "the openings are to the overall operation of the drive" or to the validity of forces that are based on derivatives of the fields.Modeling a plane wave striking an absorbing surface is a different problem than modeling the standing waves in a resonating cavity like the EM Drive.
I was referring to images like these ones, that you posted some time ago:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=705861;image)
The electromagnetic fields in that image don't look like the electromagnetic fields in the EM Drive, indicating that there was something wrong with your model of the EM Drive. Since electromagnetic forces are due to the electromagnetic fields, if one doesn't get the electromagnetic fields correctly, then it stands to reason that the calculations of electromagnetic forces in the EM Drive cannot be correct either.
Wasn't that particular simulation modeling the EM Drive without openings, which in turn showed us how important the openings are to the overall operation of the drive (at least in the simulation)?
One should not extrapolate that a two-dimensional (2D) model of the EM Drive that ignores its circular cross-section and three-dimensional field effects can be used to show valid conclusions on the importance of "the openings are to the overall operation of the drive" of the physical three-dimensional (3D) EM Drive.
A flat 2D model like this one, completely ignores for example the main electromagnetic field in the TM (transverse magnetic) 212 mode presently being tested by NASA Eagleworks. The transverse magnetic field occurs out of the plane shown in the figure, in the azimuthal direction and it has 2 full wave patterns in that circumferential direction. None of this is being modeled by this 2D Finite Difference simulation.
What QuantumG said. I'm sorry for being part of the digression. Let's focus on the EmDrive and its space-related flight applications.
Wouldn't argon be a better fuel for large EM drives, like for transfers to Mars with a lot of tonnage of equipment? Say an in space only craft that would transfer cargo to Mars flyby, let the cargo have a chemical powered craft that would land equipment and the EM craft flys back to Earth say to L1 OR L2 to pick up more cargo? Xenon is rare in comparison to argon. If the craft were large enough, it could refuel at L1 with argon plus pick up or return a Mars cargo lander. If the transfer time was fast enough, humans could also be transferred.
All that being said, with todays technology, how large would the solar panels be to say transfer 100 tons of cargo to and from Mars? Would it be better to go chemical all the way?
I would prefer to have solutions in 3D myself, but I'm not going to get them with this computer system, the meep EM thruster cavity model is to large. Its not only long run times, but also memory requirements and even hard disk storage. I had one run bomb out because I ran out of disk space while writing the output files at the end of the run
Aces High:
The hot fusion candidates you mentioned all have one major problem. That being that except for D-T fusion, no hot fusion scheme to date has ever demonstrated breakeven let alone enough energy gain over its input to make it a viable aerospace fusion reactor candidate. (I believe that the UK D-T fusion reactor may have reached breakeven for a few minute run, but Lord, look at the neutron flux it generates, which is ~70% of a pure fission reactor for a given output power, a pure fission reactor that can be much smaller and lighter than any tokomak reactor can ever be.) And after seeing what happened during the poly-well fusion reactor saga, I have great doubts as to the claims by any of the current crop of alternate fusion reactor concepts, L-M's optimistic claims about their fusion reactor design concept not withstanding.
Best, Paul M.
You're mentioning the Joint European Torus (JET) tokamak. But there are other possible paths for controlled fusion other than tokamaks. Besides Polywell and Lockheed-Martin reactors you've just cited, maybe another scheme could reach breakeven "soon" among the aneutronic p-B11 Dense Plasma Focus fusion from LPP, the (also aneutronic) Colliding Beam Fusion Reactor from Tri Alpha Energy, the colliding FRC Fusion Engine from Helion Energy, the MTF compressor from General Fusion, the MagLIF z-pinch from Sandia National Labs… None of them are based on tokamaks. Whatever, finding an appropriate energy source for the spaceship before proving the EmDrive does work is an interesting thought experiment (and perhaps mandatory for management) but it is a bit putting the cart before the horse in my opinion.
@Rodal -The general answer to the first question is: "both".
Are you telling me that an effect that shows in 2D may not show in 3D, or that an effect that exists in 3D may not show in 2D? Or both?
I would prefer to have solutions in 3D myself, but I'm not going to get them with this computer system, the meep EM thruster cavity model is to large. Its not only long run times, but also memory requirements and even hard disk storage. I had one run bomb out because I ran out of disk space while writing the output files at the end of the run.
I am forced to operate on the hope and expectation that I will be able to confirm an effect that shows in 2D by making a 3D run targeted to that effect. If I can't do that, then I can't, but I certainly can not explore the parameter space by making 3D runs.
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
I fully agree. Fretting about the energy source is a bit too much at this stage, when conclusively proving the existence of the phenomenon has yet to happen.
If this becomes a proven scientific fact, with a few more conclusive replications, finding a power source for it is just an engineering problem. That is, one based on the application of already known scientific and technical principles. We know nukes work and we have them, we know fuel cells work and we have them, the same as solar photovoltaics, etc.
Gee, if Emdrives are proven to work as H. White and Paul M. expect, we would be soon putting gasoil engines/generators to power them, and this for replacing turbofans/propellers for flying in the low atmosphere!
Even in the 2D flat model the finite difference mesh is coarse enough that one can see a fractal nature of the solution in these images:I would prefer to have solutions in 3D myself, but I'm not going to get them with this computer system, the meep EM thruster cavity model is to large. Its not only long run times, but also memory requirements and even hard disk storage. I had one run bomb out because I ran out of disk space while writing the output files at the end of the run
I'm familiar with these 2D vs 3D issues and I agree 3D is necessary.
I or others here with access to more substantial hardware can probably run said simulations for you, provided you can package up the software for us.
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
I fully agree. Fretting about the energy source is a bit too much at this stage, when conclusively proving the existence of the phenomenon has yet to happen.
If this becomes a proven scientific fact, with a few more conclusive replications, finding a power source for it is just an engineering problem. That is, one based on the application of already known scientific and technical principles. We know nukes work and we have them, we know fuel cells work and we have them, the same as solar photovoltaics, etc.
Gee, if Emdrives are proven to work as H. White and Paul M. expect, we would be soon putting gasoil engines/generators to power them, and this for replacing turbofans/propellers for flying in the low atmosphere!
I believe because of their extremely contentious nature & reputation to the majority in the scientific community it's not just a case of showing EM drives work but producing a rock solid case for why they work. Unfortunately there has been so many other claims of a similar nature that have been made over the years that have proved to be nonsense that it has severely muddied the waters leaving things such as the EM drive with incredibly high hurdles to clear before anyone gives them the time of day.
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
I fully agree. Fretting about the energy source is a bit too much at this stage, when conclusively proving the existence of the phenomenon has yet to happen.
If this becomes a proven scientific fact, with a few more conclusive replications, finding a power source for it is just an engineering problem. That is, one based on the application of already known scientific and technical principles. We know nukes work and we have them, we know fuel cells work and we have them, the same as solar photovoltaics, etc.
Gee, if Emdrives are proven to work as H. White and Paul M. expect, we would be soon putting gasoil engines/generators to power them, and this for replacing turbofans/propellers for flying in the low atmosphere!
One thing that has mystified me about this whole business is it not the fact that this effect has been known about for a number of years so why is it only in recent years that people have started looking into it?
When doing EM simulations you can model the transient propagation of radiation as it interacts with your model, which can be valuable to see exactly how it reflects and interacts with various features (like a groove, slit, etc). In this case you model an incoming pulse, composed of many frequencies.Welcome to the forum :)
Another common simulation is to do a frequency domain simulation in which you compute the steady state solution of inputting a single frequency into the model. But you have to be careful in how you interpret these results, because they are non intuitive, e.g. they don't show the propagation of radiation.
I know you can perform both types of simulation using COMSOL and CST.
I have a few questions that perhaps the emdrive experts here can answer. Why don't we use much smaller cavities? I believe they would be easier to machine, and experimentally work with. This would require scaling the wavelength, but what is the problem with that?
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
I fully agree. Fretting about the energy source is a bit too much at this stage, when conclusively proving the existence of the phenomenon has yet to happen.
If this becomes a proven scientific fact, with a few more conclusive replications, finding a power source for it is just an engineering problem. That is, one based on the application of already known scientific and technical principles. We know nukes work and we have them, we know fuel cells work and we have them, the same as solar photovoltaics, etc.
Gee, if Emdrives are proven to work as H. White and Paul M. expect, we would be soon putting gasoil engines/generators to power them, and this for replacing turbofans/propellers for flying in the low atmosphere!
I believe because of their extremely contentious nature & reputation to the majority in the scientific community it's not just a case of showing EM drives work but producing a rock solid case for why they work. Unfortunately there has been so many other claims of a similar nature that have been made over the years that have proved to be nonsense that it has severely muddied the waters leaving things such as the EM drive with incredibly high hurdles to clear before anyone gives them the time of day.
Given the figures the predicted thrust that paul march provided us. Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.
which is why I replied to Paul on the issue of power source when he mentioned LERN.
the issue didn´t really started as a discussing about what´s the best power source... I don´t really care what will the power source, nor am I interested in discussing here which power producing method has the most potential, whatever.
the issue I had here was how the scientific community looks at the EM Drive and the Eagleworks Lab experiments,which ARE fringe, and how will they look at what is already considered fringe physics if powerpoint presentations include LERN stuff...
Am I that wrong in those fears?
Microwave communications on satellites wasn't it first noted.One thing that has mystified me about this whole business is it not the fact that this effect has been known about for a number of years so why is it only in recent years that people have started looking into it?
It's not clear, what effect are you referring to?
Microwave communications on satellites wasn't it first noted.
Microwave communications on satellites wasn't it first noted.One thing that has mystified me about this whole business is it not the fact that this effect has been known about for a number of years so why is it only in recent years that people have started looking into it?
It's not clear, what effect are you referring to?
QuoteMicrowave communications on satellites wasn't it first noted.
From what I've read, yes.
Shawyer was investigating why certain satellites were burning through their fuel far faster than expected. He concluded that microwave emissions from devices on board these satellites was responsible, and from there began looking into this as a means of thrust.
which is why I replied to Paul on the issue of power source when he mentioned LERN.
the issue didn´t really started as a discussing about what´s the best power source... I don´t really care what will the power source, nor am I interested in discussing here which power producing method has the most potential, whatever.
the issue I had here was how the scientific community looks at the EM Drive and the Eagleworks Lab experiments,which ARE fringe, and how will they look at what is already considered fringe physics if powerpoint presentations include LERN stuff...
Am I that wrong in those fears?
IMHO, no, you are right. When trying to defend yourself and your ideas from strong criticism, don't become an even bigger target. Not even by making the innocent mistake of passingly referencing another controversial topic in your slides.
Focus on the pill you want your public to swallow. And not on any other.
I reject the idea that we should stay silent and not mention certain words or areas of research to avoid offending the sensibilities of certain individuals.All best discussed in its own thread, I reckon. The problem is not the sensibilities of people. It's keeping this forum in maximum shipshape; it's a functional matter, not fashion.
...
The safer and more astute approach is to maintain a skeptical but open mind until the evidence bears it out or proves it wrong. And in the meanwhile, fear, uncertainty, and doubt of discussing LENR and its possible implications for the EM Drive should be replaced with skepticism, open-mindedness, and a willingness to role up the sleeves and try things.
The microwave communications are possible because microwaves are transmitted from (and to) the satellite. The microwaves obviously are leaving (or entering) the satellite. If there is any propulsion resulting from communications from the satellite, it may not violate the laws of conservation of momentum and conservation of energy, because the microwave photons are leaving the sateliite. It would work like a photon rocket for microwaves leaving the satellite (or like a solar sail for microwave photons hitting the satellite). Scientists have no problems with the concept of a photon rocket (except that it is one the least useful forms of space propulsion: one can also use a military searchlight as a photon rocket).
Shawyer's EM Drive is completely different: it is a completely enclosed cavity. The microwaves inside it are standing waves. No microwaves leave the EM Drive. No photons leave the EM Drive (certainly not on purpose). That's why scientists think that the EM Drive should not be able to have any propulsion: because it appears to violate conservation of momentum.
The standing microwaves inside an EM Drive cannot be used for communication purposes because they stay inside the EM Drive: the metal acts like a Faraday cage.
So what is mystifying, if indeed Shaywer was inspired by this issue, is whether Shawyer did not understand the difference between a completely enclosed microwave cavity and a communications satellite transmitting microwaves or whether the story that he was inspired by this is not really accurate.
It would be like somebody saying that they invented a new form of space propulsion based on a flashlight inside a a completely sealed box with mirrors on every inside surface, and claiming that they were inspired by noticing that a satellite in space flashing a light for communications purposes, also acts like a photon rocket.
Yes, a flashlight in space will act like a photon rocket, but if you put the flaslight inside a sealed box so that no light leaves the box, it is just a box sitting in space: it is no longer good for communications and it is no longer good for propulsion
Does anyone actually believe that if we had a working EmDrive with the predicted thrust capabilities that we would have a problem finding power for it?
....
So from where I am standing, power will not be an issue if the EmDrive is proven to deliver usable thrust. We as a species will find a way.
I fully agree. Fretting about the energy source is a bit too much at this stage, when conclusively proving the existence of the phenomenon has yet to happen.
If this becomes a proven scientific fact, with a few more conclusive replications, finding a power source for it is just an engineering problem. That is, one based on the application of already known scientific and technical principles. We know nukes work and we have them, we know fuel cells work and we have them, the same as solar photovoltaics, etc.
Gee, if Emdrives are proven to work as H. White and Paul M. expect, we would be soon putting gasoil engines/generators to power them, and this for replacing turbofans/propellers for flying in the low atmosphere!
I believe because of their extremely contentious nature & reputation to the majority in the scientific community it's not just a case of showing EM drives work but producing a rock solid case for why they work. Unfortunately there has been so many other claims of a similar nature that have been made over the years that have proved to be nonsense that it has severely muddied the waters leaving things such as the EM drive with incredibly high hurdles to clear before anyone gives them the time of day.
which is why I replied to Paul on the issue of power source when he mentioned LERN.
the issue didn´t really started as a discussing about what´s the best power source... I don´t really care what will the power source, nor am I interested in discussing here which power producing method has the most potential, whatever.
the issue I had here was how the scientific community looks at the EM Drive and the Eagleworks Lab experiments,which ARE fringe, and how will they look at what is already considered fringe physics if powerpoint presentations include LERN stuff...
Am I that wrong in those fears?Given the figures the predicted thrust that paul march provided us. Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.
well, it´s about 1250 kN is about two times the thrust of a Merlin 1D engine from the Falcon 9...
he also mentioned 1 million of ISP... I guess that´s like having the power of a Merlin 1D engine consuming the same fuel per second as an electric bycicle??
I GUESS a single one would be enough to counter gravity and take a Falcon 9 rocket to space. However, because of the Falcon 9 weight and the thrust equivalent of only 2 merlin engines, it would probably take longer to get to orbit (which as you know is a matter of speed, not height).
But considering the ISP of 1 million (so little fuel being consumed per second) it HAS THE TIME to accelerate to orbital speed in the vacuum, while a normal rocket doesn´t have it (fuel ends fast, if it hasnt reached orbital speed, it falls).
I guess you could use it at like 45 degrees angle... half of thrust to keep it in space vacuum while the other half is horizontal speed to gather orbital speed?
Once in orbit... a single motor with 1250 N of thrust and 1 million of ISP can do wonders. Anyone wants to calculate the acceleration possible with such motor and a ship the weight of a fully loaded Falcon 9? (after all, he asked how it compared to current rockets)
Let's not get carried away here! Our COMSOL/Q-V plasma code simulation indicated ~1,250 Newton for 100kW RF input using a water cooled version of our current copper cavity, NOT 1,250 kN, which is three orders of magnitude larger than stated in my previous post. I'm still trying to wrap my head around this 1,250 to 2,000 Newton figure...
Aces-high:
"well, it´s about 1250 kN is about two times the thrust of a Merlin 1D engine from the Falcon 9..."
Let's not get carried away here! Our COMSOL/Q-V plasma code simulation indicated ~1,250 Newton for 100kW RF input using a water cooled version of our current copper cavity, NOT 1,250 kN, which is three orders of magnitude larger than stated in my previous post. I'm still trying to wrap my head around this 1,250 to 2,000 Newton figure...
Best, Paul M.
Given the figures the predicted thrust that paul march provided us. Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.
The problem is not the sensibilities of people.
It appears my previous post got deleted.
So I'll ask again. Has this psudoscience nonsense been found to be false yet? Have any proper scientists tested this contraption so that they can show that it doesn't work?
I'm sure some "proper scientists" will come round for a look eventually. In the meantime, history has a lot to teach us about these sorts of things:
http://amasci.com/weird/vindac.html
http://www.lifehack.org/articles/lifestyle/6-world-changing-ideas-that-were-originally-rejected.html
http://www.cracked.com/article_18822_5-famous-scientists-dismissed-as-morons-in-their-time.html
Every previous world changing idea didn't try to violate a founding principal of all physics, namely CoE and CoM.QuoteQuote...so that they can show that it doesn't work
Just curious, what makes you so certain that it doesn't work? I mean, I have no idea if it works or not. The only certain thing I know here is that I don't know for certain if it works or doesn't.
There is a growing body of evidence which suggest that it does work. It hasn't been proven by anybody that it doesn't work.
I'm still waiting for an actual test of the operation of this craft. There haven't been any non-faulty experiments done yet that actually show it producing any thrust. Namely it must be tested in a vacuum. I don't try to merge philosophy and science and currently this "EM Drive" is purely in the realm of philosophy with no actual data yet. Thus I dismiss it just like the people claiming they made an anti-gravity drive in their garage.
It's rather insulting that this forum topic even exists here.
Well I can't fault you for being skeptical, but I do urge you to review the pages of this thread. Things start getting rather interesting around page 20 or so. Many of your concerns have been addressed here, such as the vacuum testing, which has been completed with data provided, and reported here by an engineer at Eagleworks.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608
Also interesting:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333835#msg1333835
And, in my humble opinion, there has been plenty of existing, published in reputable journals...science uncovered, which can shed light on how the EMdrive can thrust, without violating any conservation laws.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1330846#msg1330846
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333392#msg1333392
Also @Notsosureofit has developed his own very plausible ideas about how EMdrive can thrust, using good old established science. @Rodal, @Aero, and @Frobnicat have all provided exhaustive data and calculations both for and against the reports of measured thrust at Eagleworks and NWPU China.
We're openly hostile to pseudoscience here, but at the same time, we must be mindful that in order to get to the bottom of this mystery, we have to be willing to step outside of our comfort zones.
From a practical standpoint, I find it extremely unlikely that the only means mankind will ever have to propel spacecraft through the vacuum, is to carry along stores of fuel and shoot propellant out the back side.
If EMdrives aren't the answer, the lessons learned from this may lead to the answer. Once field propulsion is a reality, we can consider the solar system to be unlocked.
Now that is worth a look.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
"We don't know how, why, or if it works and known physics do not readily suffice, therefore it doesn't work and its proponents are perpetuating fraud" is jumping the gun a bit, don't you think?
Tornados don't produces magical instruments. They produce junk. Luck doesn't make engineering.
The chances of someone stumbling upon some contraption by throwing electronics parts out of his garage together is nil.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
"We don't know how, why, or if it works and known physics do not readily suffice, therefore it doesn't work and its proponents are perpetuating fraud" is jumping the gun a bit, don't you think?
Think of the analogy: somebody is inspired by noticing that a flashlight used for communications from space also acts as a photon rocket. Or, as you propose, it actually has even more thrust than a photon rocket.QuoteThe microwave communications are possible because microwaves are transmitted from (and to) the satellite. The microwaves obviously are leaving (or entering) the satellite. If there is any propulsion resulting from communications from the satellite, it may not violate the laws of conservation of momentum and conservation of energy, because the microwave photons are leaving the sateliite. It would work like a photon rocket for microwaves leaving the satellite (or like a solar sail for microwave photons hitting the satellite). Scientists have no problems with the concept of a photon rocket (except that it is one the least useful forms of space propulsion: one can also use a military searchlight as a photon rocket).
Shawyer's EM Drive is completely different: it is a completely enclosed cavity. The microwaves inside it are standing waves. No microwaves leave the EM Drive. No photons leave the EM Drive (certainly not on purpose). That's why scientists think that the EM Drive should not be able to have any propulsion: because it appears to violate conservation of momentum.
The standing microwaves inside an EM Drive cannot be used for communication purposes because they stay inside the EM Drive: the metal acts like a Faraday cage.
So what is mystifying, if indeed Shaywer was inspired by this issue, is whether Shawyer did not understand the difference between a completely enclosed microwave cavity and a communications satellite transmitting microwaves or whether the story that he was inspired by this is not really accurate.
It would be like somebody saying that they invented a new form of space propulsion based on a flashlight inside a a completely sealed box with mirrors on every inside surface, and claiming that they were inspired by noticing that a satellite in space flashing a light for communications purposes, also acts like a photon rocket.
Yes, a flashlight in space will act like a photon rocket, but if you put the flaslight inside a sealed box so that no light leaves the box, it is just a box sitting in space: it is no longer good for communications and it is no longer good for propulsion
My guess - and its no more than that - is that Shawyer concluded the 'thrust' produced by these microwave emitters was significantly greater than that of a photon rocket effect.
Despite a fair number of internet searches, I have yet to encounter any details on Shawyer's research into this.
....
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
"We don't know how, why, or if it works and known physics do not readily suffice, therefore it doesn't work and its proponents are perpetuating fraud" is jumping the gun a bit, don't you think?
It would be pretty counterproductive if we took the OP's stance to a lot of quantum physics. The world of the quantum often seems to do its own thing and whether it and classical physics will ever be able to coexist happily seems from a layman's viewpoint very much up for debate. But unfortunately saying anything further would be thread drift.
@CW you mean something like a quantum wake?
Aces-high:
"well, it´s about 1250 kN is about two times the thrust of a Merlin 1D engine from the Falcon 9..."
Let's not get carried away here! Our COMSOL/Q-V plasma code simulation indicated ~1,250 Newton for 100kW RF input using a water cooled version of our current copper cavity, NOT 1,250 kN, which is three orders of magnitude larger than stated in my previous post. I'm still trying to wrap my head around this 1,250 to 2,000 Newton figure...
Best, Paul M.
bah, just a 3 orders of magnitude difference!
oops :-[ :-[
well Paul, you might want to answer Birchoff's question directly?Quote from: BirchoffGiven the figures the predicted thrust that paul march provided us. Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.
Aces-high:
Well what's a few zeros between friends?! :)
In regards to Birchoff's question, (Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.), well, lets say the Eagleworks COMSOL / Q-V plasma code is really providing accurate thrust predictions in its current V1.1 status, remembering that even Microsoft took to V3.1 to get the first really working version of Windows to a point of use-ability, i.e. we only just started to experimentally verify this code, what does ~1,300 Newton bring to the table as far as rocket applications are concerned?
The EM-Drive applications all depends on the thrust to mass ratio of the Q-Thruster AND its supporting power supply, structure and payload, and for how long the power supply & its energy source in question can operate. If its thrust to weight (T/W) ratio is less than 1-to-1, then this is a in space based propulsion system that first has to be placed into orbit by chemical rockets. If its greater than 1-to-1 and it can operate for long enough, then this EM-Drive rocket could place itself into LEO and perhaps beyond for that all depends on how long its batteries/reactor can keep supply power.
Best, Paul M.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
"We don't know how, why, or if it works and known physics do not readily suffice, therefore it doesn't work and its proponents are perpetuating fraud" is jumping the gun a bit, don't you think?
Tornados don't produces magical instruments. They produce junk. Luck doesn't make engineering.
The chances of someone stumbling upon some contraption that violates physics principles by throwing electronics parts out of his garage together is nil.
Aces-high:
Well what's a few zeros between friends?! :)
In regards to Birchoff's question, (Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.), well, lets say the Eagleworks COMSOL / Q-V plasma code is really providing accurate thrust predictions in its current V1.1 status, remembering that even Microsoft took to V3.1 to get the first really working version of Windows to a point of use-ability, i.e. we only just started to experimentally verify this code, what does ~1,300 Newton bring to the table as far as rocket applications are concerned?
The EM-Drive applications all depends on the thrust to mass ratio of the Q-Thruster AND its supporting power supply, structure and payload, and for how long the power supply & its energy source in question can operate. If its thrust to weight (T/W) ratio is less than 1-to-1, then this is a in space based propulsion system that first has to be placed into orbit by chemical rockets. If its greater than 1-to-1 and it can operate for long enough, then this EM-Drive rocket could place itself into LEO and perhaps beyond for that all depends on how long its batteries/reactor can keep supply power.
Best, Paul M.
I think that you could get away with a ratio of less than 1-to-1, if you use the propulsive force to accelerate like an airplane. Difference being, an airplane needs a dense enough atmosphere to further accelerate and gain altitude (which becomes a problem as of certain altitudes), while an EM-drive on a plane-shaped body could still accelerate further and further in a thinning atmosphere to gain tangential momentum and eventually reach orbit.
Aces-high:
Well what's a few zeros between friends?! :)
In regards to Birchoff's question, (Anyone mind educating this lay person on how a single EmDrive thruster would perform vs our current rockets.), well, lets say the Eagleworks COMSOL / Q-V plasma code is really providing accurate thrust predictions in its current V1.1 status, remembering that even Microsoft took to V3.1 to get the first really working version of Windows to a point of use-ability, i.e. we only just started to experimentally verify this code, what does ~1,300 Newton bring to the table as far as rocket applications are concerned?
The EM-Drive applications all depends on the thrust to mass ratio of the Q-Thruster AND its supporting power supply, structure and payload, and for how long the power supply & its energy source in question can operate. If its thrust to weight (T/W) ratio is less than 1-to-1, then this is a in space based propulsion system that first has to be placed into orbit by chemical rockets. If its greater than 1-to-1 and it can operate for long enough, then this EM-Drive rocket could place itself into LEO and perhaps beyond for that all depends on how long its batteries/reactor can keep supply power.
Best, Paul M.
I think that you could get away with a ratio of less than 1-to-1, if you use the propulsive force to accelerate like an airplane. Difference being, an airplane needs a dense enough atmosphere to further accelerate and gain altitude (which becomes a problem as of certain altitudes), while an EM-drive on a plane-shaped body could still accelerate further and further in a thinning atmosphere to gain tangential momentum and eventually reach orbit.
However if we apply a spatially crossed E-field and B-field across this volume, then we have a Lorentz force produced on the plasma ions that is at right angles to the applied E-field and B-field. Then BOTH the positive and negative ions will be accelerated in the SAME direction,Hello,
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
How do rockets work? They push out hot gas - the rocket goes direction x, the gas direction -x .
How does the hypothesized Q-thruster work? It pushes out QV particle 'plasma' - the Q-thruster goes direction x, the QV particle 'plasma' direciton -x .
What's the difference? In case of a rocket, we can still 'see' the hot gas. In case of the Q-thruster, we cannot. Philosophically speaking, it does not matter if you use QV particle 'plasma' or 'real' particles. Both types can be considered a subset of what 'quantum vacuum' is - namely the superset of all that can possibly exist.
It's just interesting to think about CoM. I think that the most likely reaction would be that in direction of acceleration, the Q-thruster should produce a sort of 'suction effect', and a repelling effect on the opposite side. Reason being that when the virtual plasma particle pairs vanish again, the impeded momentum must be conserved still in some form. I can only imagine this as a unidirectional 'gravity'-like effect, or maybe an effect similar to a water jet engine's behaviour. Just that in this case the fabric of spacetime itself is being used instead of water. It seems clear to me that not only should a working Q-thruster propel itself, but also create clearly measurable local side-effects.
What do you guys think?
Think of the analogy: somebody is inspired by noticing that a flashlight used for communications from space also acts as a photon rocket. Or, as you propose, it actually has even more thrust than a photon rocket.QuoteThe microwave communications are possible because microwaves are transmitted from (and to) the satellite. The microwaves obviously are leaving (or entering) the satellite. If there is any propulsion resulting from communications from the satellite, it may not violate the laws of conservation of momentum and conservation of energy, because the microwave photons are leaving the sateliite. It would work like a photon rocket for microwaves leaving the satellite (or like a solar sail for microwave photons hitting the satellite). Scientists have no problems with the concept of a photon rocket (except that it is one the least useful forms of space propulsion: one can also use a military searchlight as a photon rocket).
Shawyer's EM Drive is completely different: it is a completely enclosed cavity. The microwaves inside it are standing waves. No microwaves leave the EM Drive. No photons leave the EM Drive (certainly not on purpose). That's why scientists think that the EM Drive should not be able to have any propulsion: because it appears to violate conservation of momentum.
The standing microwaves inside an EM Drive cannot be used for communication purposes because they stay inside the EM Drive: the metal acts like a Faraday cage.
So what is mystifying, if indeed Shaywer was inspired by this issue, is whether Shawyer did not understand the difference between a completely enclosed microwave cavity and a communications satellite transmitting microwaves or whether the story that he was inspired by this is not really accurate.
It would be like somebody saying that they invented a new form of space propulsion based on a flashlight inside a a completely sealed box with mirrors on every inside surface, and claiming that they were inspired by noticing that a satellite in space flashing a light for communications purposes, also acts like a photon rocket.
Yes, a flashlight in space will act like a photon rocket, but if you put the flaslight inside a sealed box so that no light leaves the box, it is just a box sitting in space: it is no longer good for communications and it is no longer good for propulsion
My guess - and its no more than that - is that Shawyer concluded the 'thrust' produced by these microwave emitters was significantly greater than that of a photon rocket effect.
Despite a fair number of internet searches, I have yet to encounter any details on Shawyer's research into this.
....
Does it make sense then that the person being "inspired" by this would put the flashlight inside a sealed box, such that the flashlight cannot longer work as a communication device or as a super photon rocket?
Being inspired by microwave communications satellites and reacting by enclosing it inside a Faraday cage where the microwaves cannot escape doesn't make any sense to me.
If he was inspired by the microwave communications satellites his first design should have looked like a satellite's microwave antenna:
(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2009/04/artemis/9519912-4-eng-GB/ARTEMIS_medium.jpg)
(http://media-1.web.britannica.com/eb-media/24/4624-004-0ED4DA55.jpg)
instead of a sealed box: a truncated cone without any openings:
(http://emdrive.com/images/feasibility3.jpg)
No wonder then that you couldn't find anything supporting this story. It is a contradictory story that hangs from a thread: that Roger Shawyer was a consultant to the Galileo project (Europe’s satnav system), but this "inspiration story" conceals the fact that Shawyer's EM Drive is not at all like a microwave communications antenna, since it is designed such that the microwaves canNOT escape the EM Drive, which is the opposite of the design of a microwave communications antenna.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
I'm not really certain that you can call this snake oil.
Physics wise, energy is being generated, which consumes a form of fuel, be it nuclear, fossile or solar energy, energy is being generated.
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.
So, in theory, it should be possible to convert generated electrical energy into kinetic energy, which, in normal circumstances, is typically done via the use of either motors or mass being expelled at a high velocity, typically using heat to produce a high amount of directionalized kinetic energy in said mass. Thus, it is not beyond the realms of physics that it may be possible to convert electrical energy directly into kinetic energy. There would, of course, be some loss or energy as heat, but, in theory, it should be possible.
Whether or not this is what is happening here is unknown, but SOMETHING appears to be happening, (namely the imparting of thrust through non-normal means,) beyond the realm of "noise" in the experiment, thay as yet, cannot be fully explained.
I think thay trying to figure out what is happening, and whether or not it is some artifact of the experiment or an actual force that can be utilized, goes well beyond "snake oil" directly into science.
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.Conservation of momentum is as fundamental a property as conservation of energy, and it is the former which many critics believe is violated by the EM drive.
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.Conservation of momentum is as fundamental a property as conservation of energy, and it is the former which many critics believe is violated by the EM drive.
~Kirk
....
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.
So, in theory, it should be possible to convert generated electrical energy into kinetic energy, which, in normal circumstances, is typically done via the use of either motors or mass being expelled at a high velocity, typically using heat to produce a high amount of directionalized kinetic energy in said mass. Thus, it is not beyond the realms of physics that it may be possible to convert electrical energy directly into kinetic energy. There would, of course, be some loss or energy as heat, but, in theory, it should be possible.
...
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.Conservation of momentum is as fundamental a property as conservation of energy, and it is the former which many critics believe is violated by the EM drive.
~Kirk
Conservation of momentum is satisfied in Maxwell's equations, Newtonian mechanics, special relativity, general relativity, quantum mechanics and quantum electrodynamics.
In relativity, momentum and energy are both tied up together in the energy-momentum tensor.
....
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.
So, in theory, it should be possible to convert generated electrical energy into kinetic energy, which, in normal circumstances, is typically done via the use of either motors or mass being expelled at a high velocity, typically using heat to produce a high amount of directionalized kinetic energy in said mass. Thus, it is not beyond the realms of physics that it may be possible to convert electrical energy directly into kinetic energy. There would, of course, be some loss or energy as heat, but, in theory, it should be possible.
...
If electrical energy can be converted directly into spacecraft's momentum, without any matter or energy leaving the spacecraft then many problems appear.
One interesting problem has been repeatedly pointed out by @frobnicat in this thread. Since the kinetic energy is:
K = (1/2) m v^2
The power needed to accelerate (a question appearing in this thread over the last few pages concerning a comparison with chemical rockets) is dK/dt,and since in this EM Drive spacecraft, the mass doesn't change, the only thing that changes is the velocity, therefore:
dK/dt = (1/2) m [2 v dv/dt] = m v a
So the power needed to accelerate is a function of not only the acceleration wanted, but also the speed at which you're currently traveling. But, according to relativity, there is no absolute measurement of spacecraft speed, it depends on the observer. So, the needed power (to escape the surface of the Earth, etc.) depends on your frame of reference.
For a conventional rocket, the delta V is related to the mass of the spacecraft decreasing, see http://en.wikipedia.org/wiki/Delta-v for example. For the EM Drive there is no decrease of mass of the spacecraft (and if one adheres to the assumption that the Quantum Vacuum (QV) is immutable and indestructible, the QV being the zero point energy, the energy=mass*c^2 of the QV shouldn't change either). So one has a conundrum.
So, no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces).
There are several paradoxes with the EM Drive related to this.
(http://figures.boundless.com/12999/full/figure-09-07-01a.jpe)
....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://www.projectrho.com/public_html/rocket/images/reactionlessdrive/sub03.jpg)
If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://www.projectrho.com/public_html/rocket/images/reactionlessdrive/sub03.jpg)
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://www.projectrho.com/public_html/rocket/images/reactionlessdrive/sub03.jpg)
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
If the Quantum Vacuum is instead like a fluid (experiencing vortices and streamlines for example) as Paul March hinted (perhaps because our universe is part of a higher multidimensional multiverse as described by string theory and the QV was there before the Big Bang) and if it can be used for space propulsion, it may also be used for energy (as a loose analogy one can use the wind to sail the ocean as well as to produce energy with windmills) for peaceful as well as for destructive purposes... Of course, this is just science fiction at the moment, certainly as to the destructive purposes (as we cannot yet even control the weather for destructive purposes, although we have been able to use the wind for sailing and energy production for centuries).
The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
If the Quantum Vacuum is instead like a fluid (experiencing vortices and streamlines for example) as Paul March hinted (perhaps because our universe is part of a higher multidimensional multiverse as described by string theory and the QV was there before the Big Bang) and if it can be used for space propulsion, it may also be used for energy (as a loose analogy one can use the wind to sail the ocean as well as to produce energy with windmills) for peaceful as well as for destructive purposes... Of course, this is just science fiction at the moment, certainly as to the destructive purposes (as we cannot yet even control the weather for destructive purposes, although we have been able to use the wind for sailing and energy production for centuries).
The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
If the Quantum Vacuum is instead like a fluid (experiencing vortices and streamlines for example) as Paul March hinted (perhaps because our universe is part of a higher multidimensional multiverse as described by string theory and the QV was there before the Big Bang) and if it can be used for space propulsion, it may also be used for energy (as a loose analogy one can use the wind to sail the ocean as well as to produce energy with windmills) for peaceful as well as for destructive purposes... Of course, this is just science fiction at the moment, certainly as to the destructive purposes (as we cannot yet even control the weather for destructive purposes, although we have been able to use the wind for sailing and energy production for centuries).
The movie Interstellar counted with a team of leading, well respected, academic Physicists, led by Kip Thorne from CalTech as consultants. Look at the end of Interstellar for what some leading physicists think that the future may bring (the part after the leading actor comes back from the black hole)...The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
If the Quantum Vacuum is instead like a fluid (experiencing vortices and streamlines for example) as Paul March hinted (perhaps because our universe is part of a higher multidimensional multiverse as described by string theory and the QV was there before the Big Bang) and if it can be used for space propulsion, it may also be used for energy (as a loose analogy one can use the wind to sail the ocean as well as to produce energy with windmills) for peaceful as well as for destructive purposes... Of course, this is just science fiction at the moment, certainly as to the destructive purposes (as we cannot yet even control the weather for destructive purposes, although we have been able to use the wind for sailing and energy production for centuries).
Thank you for that clear explanation, is it something that could ever be proved either way experimentally? It sounds a little like the assumption that Gravity is the same everywhere in the universe which some are now disputing. But that's thread drift again.
we use the fact that, when real photons are emitted (and propagate at the speed of light), the photons leave a small afterglow of virtual photons that propagate slower than light. This afterglow does not carry energy (in contrast to real photons), but it does carry information about the event that generated the light. Receivers can 'tap' into that afterglow, spending energy to recover information about light that passed by a long time ago
We show that it is possible to use a massless field in the vacuum to communicate in such a way that the signal travels arbitrarily slower than the speed of light and such that no energy is transmitted from the sender to the receiver. Instead, the receiver has to supply a signal-dependent amount of work to switch his detector on and off. This type of communication is related to Casimir-like interactions, and it is made possible by dimension—and curvature—dependent subtleties of Huygens’ principle.
....
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.
...
If electrical energy can be converted directly into spacecraft's momentum, without any matter or energy leaving the spacecraft then many problems appear.
One interesting problem has been repeatedly pointed out by @frobnicat in this thread. Since the kinetic energy is:
K = (1/2) m v^2
The power needed to accelerate (a question appearing in this thread over the last few pages concerning a comparison with chemical rockets) is dK/dt,and since in this EM Drive spacecraft, the mass doesn't change, the only thing that changes is the velocity, therefore:
dK/dt = (1/2) m [2 v dv/dt] = m v a
So the power needed to accelerate is a function of not only the acceleration wanted, but also the speed at which you're currently traveling. But, according to relativity, there is no absolute measurement of spacecraft speed, it depends on the observer. So, the needed power (to escape the surface of the Earth, etc.) depends on your frame of reference.
So, no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces).
There are several paradoxes with the EM Drive related to this.
If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://www.projectrho.com/public_html/rocket/images/reactionlessdrive/sub03.jpg)
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created, whether now or in the early universe, through astrophysical processes or in a laboratory. Another reason is that the Quantum Vacuum has what Albert Einstein in 1913 called "Nullpunktsenergie" (zero point energy): the lowest possible (time-averaged) energy that a quantum mechanical physical system may have.Could you expand on that to help out a poor layperson to these matters, I hadn't realised that the QV being described in this way was such a fundamental cornerstone of physics as it stands?....If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
If the Quantum Vacuum is instead like a fluid (experiencing vortices and streamlines for example) as Paul March hinted (perhaps because our universe is part of a higher multidimensional multiverse as described by string theory and the QV was there before the Big Bang) and if it can be used for space propulsion, it may also be used for energy (as a loose analogy one can use the wind to sail the ocean as well as to produce energy with windmills) for peaceful as well as for destructive purposes... Of course, this is just science fiction at the moment, certainly as to the destructive purposes (as we cannot yet even control the weather for destructive purposes, although we have been able to use the wind for sailing and energy production for centuries).
@Star-Drive
This is all very exciting. I cannot wait to read it and then pretend I understand.
The very best of luck to you Paul and your colleagues, and no pressure, but:
@Star-Drive
This is all very exciting. I cannot wait to read it and then pretend I understand.
The very best of luck to you Paul and your colleagues, and no pressure, but:
It's already past the point when the Eagleworks team should have found results or their funding gets pulled, and there has been no response to a contributor on this thread who asked a direct question about this point. I wouldn't get your hopes up.
....
In theory, according to basic physics, it should be possible to convert one form of energy into another, such as kinetic energy being converted to heat energy as a vehicle is decellerated via air during reentry.
...
If electrical energy can be converted directly into spacecraft's momentum, without any matter or energy leaving the spacecraft then many problems appear.
One interesting problem has been repeatedly pointed out by @frobnicat in this thread. Since the kinetic energy is:
K = (1/2) m v^2
The power needed to accelerate (a question appearing in this thread over the last few pages concerning a comparison with chemical rockets) is dK/dt,and since in this EM Drive spacecraft, the mass doesn't change, the only thing that changes is the velocity, therefore:
dK/dt = (1/2) m [2 v dv/dt] = m v a
So the power needed to accelerate is a function of not only the acceleration wanted, but also the speed at which you're currently traveling. But, according to relativity, there is no absolute measurement of spacecraft speed, it depends on the observer. So, the needed power (to escape the surface of the Earth, etc.) depends on your frame of reference.
So, no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces).
There are several paradoxes with the EM Drive related to this.
A possible exception to this restriction is the lorentz force. Satellites use torque coils to dump angular momentum. Space tethers, if they ever are shown to work, transfer momentum to the Earth when current flowing along the tether is normal to the Earth's magnetic field. The return path is provided by ions. In fact any current-carrying wire experiences a lorentz force with a direction that is the cross product of the current direction and the magnetic field direction. The force is the same if the wire is stationary or is moving. So, in the case of an electrodynamic tether the restriction:
dK/dt = (1/2) m [2 v dv/dt] = m v a
Doesn't apply. How this applies to the EM-drive I can't even guess.
"according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces).
How this applies to the EM-drive I can't even guess.
@Star-Drive
This is all very exciting. I cannot wait to read it and then pretend I understand.
The very best of luck to you Paul and your colleagues, and no pressure, but:
It's already past the point when the Eagleworks team should have found results or their funding gets pulled, and there has been no response to a contributor on this thread who asked a direct question about this point. I wouldn't get your hopes up.
@Star-Drive
This is all very exciting. I cannot wait to read it and then pretend I understand.
The very best of luck to you Paul and your colleagues, and no pressure, but:
It's already past the point when the Eagleworks team should have found results or their funding gets pulled, and there has been no response to a contributor on this thread who asked a direct question about this point. I wouldn't get your hopes up.
Whoops, let that one slip by. Just for the record I think due to team's other work on the theoretical side the Q-V, I was given a reprieve on my contract termination date until the end of September 2015. Management still wants us to perform and IV&V at Glenn Research Center (GRC), but appears to be willing to wait a few months more until we can get our arms around increasing the current test setup's thrust up to a repeatable 100+uN force every time we apply power. Right now its about every third time that I can find the "Just-So" conditions needed to evoke the thrust signature in the reversed thrust mode.
Best, Paul M.
@Star-Drive
This is all very exciting. I cannot wait to read it and then pretend I understand.
The very best of luck to you Paul and your colleagues, and no pressure, but:
It's already past the point when the Eagleworks team should have found results or their funding gets pulled, and there has been no response to a contributor on this thread who asked a direct question about this point. I wouldn't get your hopes up.
Whoops, let that one slip by. Just for the record I think due to team's other work on the theoretical side the Q-V, I was given a reprieve on my contract termination date until the end of September 2015. Management still wants us to perform and IV&V at Glenn Research Center (GRC), but appears to be willing to wait a few months more until we can get our arms around increasing the current test setup's thrust up to a repeatable 100+uN force every time we apply power. Right now its about every third time that I can find the "Just-So" conditions needed to evoke the thrust signature in the reversed thrust mode.
Best, Paul M.
Is the inability to hit the "Just-So" conditions a side effect of some sort of degredation of either the cavity (as a result of thermal expansion or something similar) or the RF amplifier (failing while in vacuum)? If not can you share any ideas on what you think is impeding repeatability at the 100un level and above?
....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://ecx.images-amazon.com/images/I/51dQFZfQT2L._SY344_BO1,204,203,200_.jpg)
If the QV is not immutable and indestructible, the theoretical and practical consequences would be so groundbreaking that they would make the 20th century's discoveries of atomic and nuclear energy pale in comparison.....Even if (for discussion's sake) mass would be converted into energy with a nuclear reaction E=mc^2 inside the spacecraft to provide the electricity for the EM Drive, that does not solve the conundrum: the issue is not "to expend energy", the issue is to satisfy conservation of momentum. If no mass leaves the spacecraft, while kinetic energy is converted into a change in momentum of the spacecraft's center of mass, you still have the same conundrum and the same paradoxes I previously noted:
Be it nuclear, fuel cell or even solar, as the source of electricity, mass is being expended in the form of electrons. (Solar is taking advantage of the Sun's own expendature of mass in the form of photons). Whiloe the quantity of mass being expended is minute, it IS being expended.
...
The needed power for the EM Drive (to escape the surface of the Earth, or anything else you want the spacecraft to do) depends on your frame of reference.
As Paul March himself admitted, for their Quantum Vacuum explanation for the EM Drive to hold, they need to disrespect the mainstream physics assumption that the Quantum Vacuum is indestructible and immutable.
Bottom line: no, "according to basic physics, it should" not be possible to directly convert electrical energy into a spacecraft's momentum change without any change in mass of the spacecraft (or the action of external forces). If the EM Drive were to work for space propulsion, it certainly would not be explainable in terms of mainstream physics where conservation of momentum is paramount, and the Quantum Vacuum is both indestructible and immutable.
(http://www.projectrho.com/public_html/rocket/images/reactionlessdrive/sub03.jpg)
Just being curious: What, in your book, would be the most important theoretical consequences of the discovery of a different QV nature?
Dr. Rodal:
"If the QV is not immutable and indestructible,''')
We've not tired to make that a secret and in fact that is at the core of our Q-V conjecture and Q-V plasma code that Dr. White and Dr. Vera have written that produced the Q-Thruster thrust predictions that I posted earlier on this forum. And this new paper is an expansion of Dr. White's STAIF-2007 conjecture and a partial rebuttal to the criticisms raised by the NASA Blue Ribbon panel's critique from last summer, an independent body of eight PhDs knowledge in the field that was created by NASA/JSC/EP management to vet Dr. White's QVF/MHD conjecture. And yes, if the accumulated chemical and nuclear data keeps pointing us in the same direction as it and our own experimental data has so far, we will be able to transmit and receive momentum through the Q-V via Q-Thruster like device. AND ultimately, be able harvest energy from the Q-V based cosmological gravitational field via various thermodynamic processes, at least in the far term. So find attached the Abstract and Introduction of our "Dynamics of the Vacuum" paper that will be out on the NASA servers hopefully by the end of April.
Best, Paul M.
"One should not take this vacuum energy too literally, however, because the free-field theory is just a mathematical tool to help us understand what we are really interested in: the interacting theory. Only the interacting theory is supposed to correspond directly to reality. Because the vacuum state of the interacting theory is the state of least energy in reality, there is no way to extract the vacuum energy and use it for anything.
"It is a bit like this: say a bank found it more convenient (for some strange reason) to start counting at 1,000, so that even when you had no money in the bank, your account read $1,000. You might get excited and try to spend this $1,000, but the bank would say, 'Sorry, that $1,000 is just an artifact of how we do our bookkeeping: you're actually flat broke.'
"Similarly, one should not get one's hope up when people talk about vacuum energy. It is just how we do our bookkeeping in quantum field theory. There is much more to say about why we do our bookkeeping this funny way, but I will stop here.
The one who follows the crowd will usually get no further than the crowd. The one who walks alone, is likely to find himself/herself in places no one has ever been
this might be topical here: http://phys.org/news/2015-04-electromagnetism-enable-antennas-chip.html
Since it couples electromagnetic radiation in dielectrics with quantum phenomenon.
We report our observation that radiation from a system of accelerating charges is possible only when there is explicit breaking of symmetry in the electric field in space within the spatial configuration of the radiating system. Under symmetry breaking, current within an enclosed area around the radiating structure is not conserved at a certain instant of time resulting in radiation in free space. Electromagnetic radiation from dielectric and piezoelectric material based resonators are discussed in this context. Finally, it is argued that symmetry of a resonator of any form can be explicitly broken to create a radiating antenna.
BTW, we have also started the build of our 1.2kW magnetron powered EM-Drive prototype in a tetter-totter balance system that is being built to replicate the thrust magnitudes of the Shawyer tests and the Chinese replication of same. Estimated build time should in the 2 month time period with the limited manpower available. A picture of the chaotic magnetron spectra that will be used on this system is attached along with the TE011 mode that will be driven.
Best, Paul M.
this might be topical here: http://phys.org/news/2015-04-electromagnetism-enable-antennas-chip.html
Since it couples electromagnetic radiation in dielectrics with quantum phenomenon.
I don't want to put a tangent on this discussion here but I have a question about something that could pertain to exotic drives of this nature. I posted my question in the "ansible" thread at http://forum.nasaspaceflight.com/index.php?topic=37002.msg1355745#msg1355745
The post is reply 38 in that thread. It's about the implicit negative mass that should have to be involved in turning positive mass particles into zero mass meta-particles called unparticles in the literature. I would appreciate your thoughts (because there are some heavy hitters in this thread) but over there so as not to further disturb this thread.
We know the missing mass is zero if there is a single invisible massless particle. what missing mass do we expect for two? In any given event, we don’t know, but if we repeat the process many times, the angle between the two invisible particle momenta will be distributed at random. If there are three invisible massless particles, all three momenta have to line up exactly to get zero missing mass, even less likely to happen at random! So small missing mass is even more unlikely, and the number of events as a function of missing mass would increase even faster
In a particle detector, unparticles would look like particles with random masses. One unparticle decay might have many times the apparent mass of the next — the distribution would be broad.
While that's all very interesting. You can immediately rule out the drive's functionality because of the lack of reaction mass. CoM is clearly broken.
I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force.
I have yet to year a simple explanation of how this drive works that doesn't dive into theoretical physics to explain its operation. It is true of everything in physics that simple laws lead to complex behavior. If the operation of the EmDrive or other various families of the drive cannot be explained in an abstract way within a couple sentences then it doesn't work.
People are being sold snake oil and I don't like it.
"We don't know how, why, or if it works and known physics do not readily suffice, therefore it doesn't work and its proponents are perpetuating fraud" is jumping the gun a bit, don't you think?
Tornados don't produces magical instruments. They produce junk. Luck doesn't make engineering.
The chances of someone stumbling upon some contraption that violates physics principles by throwing electronics parts out of his garage together is nil.
"I only have a minor in physics so I honestly can't understand most of what's talked about here, but I know at the least you can't go about thrusting around the universe with no particles/energy leaving the engine without something like an Alcubierre drive. Even if you're pushing against quantum virtual particle pairs, virtual particle pairs have opposite signs so will be propelled in opposite directions thus canceling out any net force."
In a neutral plasma there is an equal number of plus and minus electrical charges or ions that can react to applied E-fields and B-fields in various ways. If there is only an electric field applied to the plasma volume then yes the positive charges will go one way and the negative charges will go in the opposite direction. However if we apply a spatially crossed E-field and B-field across this volume, then we have a Lorentz force produced on the plasma ions that is at right angles to the applied E-field and B-field. Then BOTH the positive and negative ions will be accelerated in the SAME direction, but with counter rotating twists AKA Gyro radius modifying their accelerated trajectories. All of these EM-Drive like thruster utilize some form of this Lorentz force acceleration on some type of propellant, be it real as in a Hall thruster or semi-virtual.
Best, Paul M.
Sonny White formulated a compressible quantum vacuum conjecture that requires us to live in a portion of the universe that is immersed in a false vacuum that apparently has a ground or zero-energy level much smaller than science first assumed. However what will drive this debate is experimental data first and foremost. Experimental data like what just came out of the Eagleworks Lab's latest warp-field interferometer tests based on 27,000, 1.5 second long on/off data samples that indicates we have finally observed the first spacetime contraction effects that we are fairly confident are the real deal. We again are looking for more possible false positives as well as ways of increasing the signal to noise ratio above its current ~2-to-3 sigma level, which I've already suggested several ways to do so to Dr. White. However what is really interesting about these new test results is that the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate. A similar RF resonant system used to implement the EM-Drive and Q-thruster designs, for these spacetime contraction effects are paramount to the operation of both.
Dr. Rodal:
As promised, find attached a few related papers from work. As to the rest of your and Mulletron's concerns over the Eagleworks evolving theoretical musings on the EM-Drive propulsion topic, I leave you with Boyd Bushman's, (was senior scientist at LM/FW, now retired and passed-on), admonition to me when I first met him back in 2000 when discussing Jim Woodward's Mach-Effect work with Boyd's boss, "Follow the data, theory be dammed!" We intend to do just that, no matter where it might take us.
Best, Paul M.
Based on our data, we can exclude the possibility that the gravitiational mass of antihydrogen is more than 110 times its inertial mass, or that it falls upwards with a gravitational mass more than 65 times its inertial mass.
Our results far from settle the question of antimatter gravity. But they open the way towards higher-precision measurements in the future, using the same technique, but more, and colder trapped antihydrogen atoms, and a better understanding of the systematic effects in our apparatus.
Talking of CERN will the LHC be able to help with any of this? I know they are using it to see if they can prove if super-symmetry exists.
Virtual particles are indeed real particles...But while the virtual particles are briefly part of our world they can interact with other particles, and that leads to a number of tests of the quantum-mechanical predictions about virtual particles. The first test was understood in the late 1940s. In a hydrogen atom an electron and a proton are bound together by photons (the quanta of the electromagnetic field). Every photon will spend some time as a virtual electron plus its antiparticle, the virtual positron, since this is allowed by quantum mechanics as described above. The hydrogen atom has two energy levels that coincidentally seem to have the same energy. But when the atom is in one of those levels it interacts differently with the virtual electron and positron than when it is in the other, so their energies are shifted a tiny bit because of those interactions. That shift was measured by Willis Lamb and the Lamb shift was born, for which a Nobel Prize was eventually awarded....
Another very good test some readers may want to look up, which we do not have space to describe here, is the Casimir effect, where forces between metal plates in empty space are modified by the presence of virtual particles.
Thus virtual particles are indeed real and have observable effects that physicists have devised ways of measuring.
excuse me but isn't the laser thing is an accomplished fact now? A few years ago there was a couple of related articles on a desktop accelerator that generated electrons and positrons then separated them with magnets.Good to hear that, if making real positrons out of "virtual" positrons has already been accomplished, so much the better for my point that virtual particles are indistinguishable from real particles. They don't have tags or any other features identifying them as "virtual", they are exactly the same as any other real particle except for their ephemeral life if (as they must do unless one intervenes) annihilate each other :)
http://phys.org/news/2013-06-physicists-tabletop-antimatter-gun.html
http://phys.org/news/2013-06-particle-tabletop-chapter-science.html
here is one of them and then there were two more. the third talks about (the rapidly approaching future ability) using colliding laser beams to create matter out of photons.
http://phys.org/news/2014-05-scientists-year-quest.html
http://www.newscientist.com/article/dn19327-lasers-could-make-virtual-particles-real.html
excuse me but isn't the laser thing is an accomplished fact now? A few years ago there was a couple of related articles on a desktop accelerator that generated electrons and positrons then separated them with magnets.
http://phys.org/news/2013-06-physicists-tabletop-antimatter-gun.html
http://phys.org/news/2013-06-particle-tabletop-chapter-science.html
here is one of them and then there were two more. the third talks about (the rapidly approaching future ability) using colliding laser beams to create matter out of photons.
http://phys.org/news/2014-05-scientists-year-quest.html
http://www.newscientist.com/article/dn19327-lasers-could-make-virtual-particles-real.html
Dr. Rodal:
As promised, find attached a few related papers from work. As to the rest of your and Mulletron's concerns over the Eagleworks evolving theoretical musings on the EM-Drive propulsion topic, I leave you with Boyd Bushman's, (was senior scientist at LM/FW, now retired and passed-on), admonition to me when I first met him back in 2000 when discussing Jim Woodward's Mach-Effect work with Boyd's boss, "Follow the data, theory be dammed!" We intend to do just that, no matter where it might take us.
Best, Paul M.
Paul,
Thanks so much for taking the time to dig and post these papers. The new paper by Bush (2015) from MIT, showing that one can model quantum statistics hydrodynamically, is outstanding, very clearly written. :)
...
Tried to search for answer, could not find...my apologies if already discussed:Welcome to the forum.
Has there been an accurate mass comparison on the dielectric (PTFE et al) prior to and after RF excitation?
Dr. Rodal:
As promised, find attached a few related papers from work. As to the rest of your and Mulletron's concerns over the Eagleworks evolving theoretical musings on the EM-Drive propulsion topic, I leave you with Boyd Bushman's, (was senior scientist at LM/FW, now retired and passed-on), admonition to me when I first met him back in 2000 when discussing Jim Woodward's Mach-Effect work with Boyd's boss, "Follow the data, theory be dammed!" We intend to do just that, no matter where it might take us.
Best, Paul M.
Paul,
Thanks so much for taking the time to dig and post these papers. The new paper by Bush (2015) from MIT, showing that one can model quantum statistics hydrodynamically, is outstanding, very clearly written. :)
...
Great YouTube video by Harris and Bush at MIT.
Watch that droplet ride its own guiding pilot wave, "magically" hovering over the fluid (can you describe what's responsible for its motion ? : instability due to nonlinear standing waves):
https://www.youtube.com/watch?v=nmC0ygr08tE
The great (7th duc) de Broglie, Noble Prize in Physics, recognized 90 years after his Solvay presentation: a triumph of creative imagination
(http://www.nobelprize.org/nobel_prizes/physics/laureates/1929/broglie.jpg)
Thanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.Agreed, outgassing (due to microwave heating of water vapor previously trapped in the HDPE or PTFE polymer dielectric) would be something to watch out for in a vacuum environment at significantly lower temperatures (near 200 deg F) than pyrolysis (>700 deg F).
Thanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.Agreed, outgassing (due to microwave heating of water vapor previously trapped in the HDPE or PTFE polymer dielectric) would be something to watch out for in a vacuum environment at significantly lower temperatures (near 200 deg F) than pyrolysis (>700 deg F).
Note that @Notsosureofit mentioned that nonlinearity in the dielectric could be important and that some of the papers posted by @Mulletron rely on both nonlinearity and anisotropy of the dielectric to explain thrust force as an interaction with the quantum vacuum.Dr. Rodal:
As promised, find attached a few related papers from work. As to the rest of your and Mulletron's concerns over the Eagleworks evolving theoretical musings on the EM-Drive propulsion topic, I leave you with Boyd Bushman's, (was senior scientist at LM/FW, now retired and passed-on), admonition to me when I first met him back in 2000 when discussing Jim Woodward's Mach-Effect work with Boyd's boss, "Follow the data, theory be dammed!" We intend to do just that, no matter where it might take us.
Best, Paul M.
Paul,
Thanks so much for taking the time to dig and post these papers. The new paper by Bush (2015) from MIT, showing that one can model quantum statistics hydrodynamically, is outstanding, very clearly written. :)
...
Great YouTube video by Harris and Bush at MIT.
Watch that droplet ride its own guiding pilot wave, "magically" hovering over the fluid (can you describe what's responsible for its motion ? : instability due to nonlinear standing waves):
https://www.youtube.com/watch?v=nmC0ygr08tE
...
There's one thing that has bothered me about virtual particle pairs popping in and out of existence:
When besaid pairs, for instance, pop into existence in a gravitational field like the Earth's, they do exist for a minute time span. During that time span, they are 'real' due to borrowed energy from the quantum vacuum. But real particles with mass experience an acceleration in a gravitational field and thus gain momentum. There are two cases to consider, of which only one should be correct:
1) The pair's particles react to gravity the same way and experience a momentum gain in the same direction. When they pop out of existence again, the gained momentum 'magically' disappears with the pair and CoM is broken. Momentum must not simply 'disappear' (in lack for a better word). I read somewhere that CoM is not applicable to virtual particles (can't find the link), but still this doesn't seem right.Quote from: DustinTheWind
Interesting line of thought. What if when imaginary particles become real we measure them in gravity having downward momentum, they accelerate, then go back to imaginary. Later we do the same experiment lower in the gravity field and they become real but this time they have greater momentum, accelerate, then go imaginary again. We might then suspect the quantum vacuum was already in motion and accelerating before they came into existence. Maybe the rate they pop in and out of existence determines the drag they have on normal matter?
In relation to the cavity then what if the particles become real, we give them a shove, then they become non-real and are allowed to exit the cavity by way of the quantum vacuum. Could that momentum then be imparted to the vacuum? Would we measure time space waves from it?
2) The anti-particle gains a momentum opposite to the particle's momentum due to repulsive forces on an anti-particle within a gravitational field, and so the force and momentum vectors add up to Zero at any instance in time. CoM is maintained.
What do you think?Quote from: DustinTheWindMatter that was repelled from gravity would remind me of negative energy density. I think that would be the stuff like the Alcubierre warp bubble where it shows negative energy density on one side and positive on the other to make the ship go forward by warp. Maybe gravity propulsion? Might be related to this, link: http://en.wikipedia.org/wiki/Negative_mass, "Runaway motion" top paragraph, "Although no particles are known to have negative mass..." towards the bottom, "Hence Bondi pointed out ..."<-- is he talking about the warp bubble effect?
Under this link: http://en.wikipedia.org/wiki/Negative_mass under "Gravitational interaction of antimatter" it states, "The overwhelming consensus among physicists is that antimatter has positive mass and should be affected by gravity just like normal matter. Direct experiments on neutral antihydrogen have not detected any difference between the gravitational interaction of antimatter, compared to normal matter.[19]"
As far as I knew I thought imaginary particles were matter and anti-matter. One big mystery is where did all the anti-mater in the universe go. I guess I can't say that they have measured the gravitational attraction of anti-matter yet that I know of though wiki suggests in section, "Gravitational interaction of antimatter" the "Bubble chamber experiments" as an arrow that suggests they have positive mass though don't ask me how conclusive that is.
@dustinthewind:
About creating an ExB = S Poynting vector.. wouldn't it be much easier to do this if one takes a circular electromagnet with iron core that has a relatively big air gap, and puts a highly charged plate capacitor on opposite sides of the air gap? The resulting space should be 'filled' with Poynting vectors ExB that can interact with the theorized QV plasma, which is supposed to accelerate the QV plasma and in turn accelerate the contraption.
Does that make sense, or am I missing something relevant concerning how a QV thruster should work?
EDIT: I made a drawing of a contraption I call 'Poynting vector field generator' and attached it to this message. If there's something wrong with the drawing, please tell.
EDIT: Sorry for the mix of wire frame and solid view. I was a bit lazy to tinker with the drawing program for dotted lines to indicate hidden edges ;-) .
@dustinthewind:
About creating an ExB = S Poynting vector.. wouldn't it be much easier to do this if one takes a circular electromagnet with iron core that has a relatively big air gap, and puts a highly charged plate capacitor on opposite sides of the air gap? The resulting space should be 'filled' with Poynting vectors ExB that can interact with the theorized QV plasma, which is supposed to accelerate the QV plasma and in turn accelerate the contraption.
Does that make sense, or am I missing something relevant concerning how a QV thruster should work?
EDIT: I made a drawing of a contraption I call 'Poynting vector field generator' and attached it to this message. If there's something wrong with the drawing, please tell.
EDIT: Sorry for the mix of wire frame and solid view. I was a bit lazy to tinker with the drawing program for dotted lines to indicate hidden edges ;-) .
A Poynting vector is not a field. In your drawing the Poynting vector is dispersed in all directions because the energy flow is entirely due to thermal loss. (DC case) If there are AC drives to the capacitor and gap magnet then some energy is transferred to near field RF radiation. Nothing exotic happens here. The em fields just combine.
@dustinthewind:
Hmm.. so if we go by http://en.wikipedia.org/wiki/Negative_mass (http://en.wikipedia.org/wiki/Negative_mass) as referred by you and if we assume that the 'overwhelming consensus' is that antimatter shows the same gravitational behavior as does matter, then my case 1) should be correct and CoM be broken for matter-antimatter pairs popping in and out of existence within gravitational fields. Either this is true, or CoM does not apply for those pairs. Hmm..
A Poynting vector is not a field. In your drawing the Poynting vector is dispersed in all directions because the energy flow is entirely due to thermal loss. (DC case) If there are AC drives to the capacitor and gap magnet then some energy is transferred to near field RF radiation. Nothing exotic happens here. The em fields just combine.
A Poynting vector is not a field. In your drawing the Poynting vector is dispersed in all directions because the energy flow is entirely due to thermal loss. (DC case) If there are AC drives to the capacitor and gap magnet then some energy is transferred to near field RF radiation. Nothing exotic happens here. The em fields just combine.
I don't get your point.
1. CW's drawing does not show a Poynting vector dispersed in all directions, but a very directional vector going from the left to the right in the picture.
2. That Poynting vector S = ExB actually gives a Lorentz force F = q(E + vxB) when electric charges are able to flow within the electric field. If the sum of those electric charges in movement are able to create an electric current in a continuous charge distribution, i.e. with a current density J due to the charge density ρ, the Lorentz Force is then a "3D volumetric force", accelerating all electric charges in the same direction whatever their sign, and also the neutral atoms in the plasma with them, through collisions. This is the basis of magnetohydrodynamics applied to propulsion (MHD accelerators), sometimes called magnetoplasmadynamic (MPD) thrusters when the accelerating fluid is a ionized gas.
Really I'm not sure if Harold White's idea of pushing upon virtual particles from the quantum vacuum with MHD (Lorentz forces) as if it was a real plasma is the answer. But I second CW's question about a setup like an MPD thruster, with crossed E and B fields. Applying an orthogonal magnetic field with an electromagnet would considerably enhance the propulsive Lorentz force. If I remember correctly, White's first Q-thruster (The DC version of Woodward's first Mach-Lorentz Thruster or MLT, that ran on AC) was based on that concept but was a failure -except while being powered on and off (so the DC current would transiently become AC, as per Woodward). White's Quantum Vacuum Fluctuation (QVF) conjecture does not need AC currents, only DC, contrary to Woodward's Mach Effect (ME) conjecture. Maybe Paul could clarify all this.
Feynmans's species of antiparticle might be alice matter AKA Mirror matter? If so it is theoretically possible to get some. :)
http://phys.org/news/2012-06-neutrons-parallel-world.html
http://www.technologyreview.com/view/426676/how-neutrons-might-escape-into-another-universe/
all these theories of the virtual particles having mass or not (I guess they have, otherwise wouldn´t be used for propulsion)... wouldn´t the total mass of virtual particles be much greater than the mass of even dark energy + dark matter together, and thus cause a collapse of the universe?
A Poynting vector is not a field. In your drawing the Poynting vector is dispersed in all directions because the energy flow is entirely due to thermal loss. (DC case) If there are AC drives to the capacitor and gap magnet then some energy is transferred to near field RF radiation. Nothing exotic happens here. The em fields just combine.
I don't get your point.
1. CW's drawing does not show a Poynting vector dispersed in all directions, but a very directional vector going from the left to the right in the picture.
2. That Poynting vector S = ExB actually gives a Lorentz force F = q(E + vxB) when electric charges are able to flow within the electric field. If the sum of those electric charges in movement are able to create an electric current in a continuous charge distribution, i.e. with a current density J due to the charge density ρ, the Lorentz Force is then a "3D volumetric force", accelerating all electric charges in the same direction whatever their sign, and also the neutral atoms in the plasma with them, through collisions. This is the basis of magnetohydrodynamics applied to propulsion (MHD accelerators), sometimes called magnetoplasmadynamic (MPD) thrusters when the accelerating fluid is a ionized gas.
A Poynting vector is not a field. In your drawing the Poynting vector is dispersed in all directions because the energy flow is entirely due to thermal loss. (DC case) If there are AC drives to the capacitor and gap magnet then some energy is transferred to near field RF radiation. Nothing exotic happens here. The em fields just combine.
I don't get your point.
1. CW's drawing does not show a Poynting vector dispersed in all directions, but a very directional vector going from the left to the right in the picture.
2. That Poynting vector S = ExB actually gives a Lorentz force F = q(E + vxB) when electric charges are able to flow within the electric field. If the sum of those electric charges in movement are able to create an electric current in a continuous charge distribution, i.e. with a current density J due to the charge density ρ, the Lorentz Force is then a "3D volumetric force", accelerating all electric charges in the same direction whatever their sign, and also the neutral atoms in the plasma with them, through collisions. This is the basis of magnetohydrodynamics applied to propulsion (MHD accelerators), sometimes called magnetoplasmadynamic (MPD) thrusters when the accelerating fluid is a ionized gas.
I think you might be mixing a lot of things together here and jumping to conclusions. If you believe this gap magnet and capacitor can generate reactionless thrust you should build it and test it out for yourself. I could give you 20-30 more interesting ideas I have played with in the last 15 years when you get done with that one. Just because something looks "cool" doesn't mean it has any significance.
...I'm re-appending a Rice University paper on the hydrodynamics of the vacuum for your reference and study. You will find that a Q-V plasma acts quite a bit like a water based fluid, but with some startling differences as well, since it does salute MHD rules as well AND the still curious rules of the Quantum world.Hi Paul, looking at equation (4.22) in the attachment it appears that Stevenson's hydrodynamic model for the vacuum ignores electromagnetism and shear stresses: it has all components of Poynting's vector equal to zero and all shear stress components equal to zero. The only non-zero component of Maxwell's stress tensor in Stevenson's formulation is pressure. Thus, Stevenson models the vacuum as a fluid without any viscosity, incapable of supporting any shear stress, a superfluid. He only considers the energy-density and the pressure as variables.
Best, Paul M.
...
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10.1027&rep=rep1&type=pdf
I still think we can violate newtons 3rd law in a way but in another way it is not violated because the propulsion device projects radiation out one end. This looks like radiation propulsion but by sticking a dielectric between the two current loops we can change the speed of light making the two current loops closer or lowering the frequency needed while also getting near field effects? What this does for the radiation projected I'm not exactly sure but I would assume it should intensify. This is assuming none of the current loops have constant current but are both changing in time and out of phase pi/2 (see figure EM Propulsion 2.png).
I guess the idea was if there was something similar going on inside the radiation cavity...
Just wanted to share the good news! Put a check in the box for diametric drives.
http://www.nature.com/nphys/journal/v9/n12/full/nphys2777.html?WT.ec_id=NPHYS-201312
http://phys.org/news/2013-10-optical-diametric.html
http://www.creol.ucf.edu/Research/Publications/7155.pdf
The ESA had a study called Ariadna 04/1201 and a contract called PHOTONIMPULS ANR-09-BLAN-0088-01 to investigate Feigel's claims, derive a Lorentz invariant (and correct) description of the Feigel process, and figure out if the QV can be used for propulsion:
http://www.esa.int/gsp/ACT/ariadna/projects/ari_study_04-1201.html
http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Koln_Feigel.pdf
http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Grenoble_Feigel.pdf
On the basis of our study, we come to the following conclusions: The derivation of the generally covariant relativistic constitutive relations for a moving magnetoelectric medium, together with the subsequent analysis of the vacuum waves travelling through the sample of a finite size shows that the magnetoelectric body will not move, despite the presence of a certain asummetry between the left- and right-moving waves in the matter. However, this only refers to the case of waves due to vacuum fluctuation.
For the real waves falling symmetrically from the two sides on a magnetoelectric body, we expect a nontrivial effect of the Feigel type. Thus, we cannot confirm the possibility of "extracting momentum from nothing".
"It is a prediction, but experimental results are needed. VASIMR drive finally got those funds at NASA, I would like to see something similar on EM-Drive"
So would we, but don't hold your breath. In the meantime we have enough funding for the rest of the NASA fiscal year to keep building up our 0.12-to-1.2kW, WR-340 waveguide based EM-Drive magnetron system on a teeter-totter balance system using a earlier aluminum frustum as our test article. The build of that experiment should be completed by the end of June using just civil servant labor and the existing hardware on hand. Then we get to see if Shawyer's and the Chinese's reported EM-Drive results are the real deal, or not.
Paul March has nicely summarized funding and future of the EM Drive project at NASA, a few hours ago in the Advanced Propulsion thread of LinkedIn, as follows:Quote"It is a prediction, but experimental results are needed. VASIMR drive finally got those funds at NASA, I would like to see something similar on EM-Drive"
So would we, but don't hold your breath. In the meantime we have enough funding for the rest of the NASA fiscal year to keep building up our 0.12-to-1.2kW, WR-340 waveguide based EM-Drive magnetron system on a teeter-totter balance system using a earlier aluminum frustum as our test article. The build of that experiment should be completed by the end of June using just civil servant labor and the existing hardware on hand. Then we get to see if Shawyer's and the Chinese's reported EM-Drive results are the real deal, or not.
@ Mulletron
Great find!
Separating the two photon directions allows them to control their interaction (equivalent of the cavity taper and/or dielectric). In the EMdrive the two directions are intimately coupled within the cavity. If you fold figure 1 in half (vertical fold line) you have something like a tapered microwave cavity. I don't see the need to invoke negative mass (they did say effectively) as the same description looks like the "self accelerating" particle papers.
The question is "is the nonlinearity a required condition ?".
Thanks for that. But you know what they say extraordinary claims require extraordinary evidence. I'm sure if this is ever proven too a sufficient degree they'll have no problem obtaining funding.
@ Mulletron
Great find!
Separating the two photon directions allows them to control their interaction (equivalent of the cavity taper and/or dielectric). In the EMdrive the two directions are intimately coupled within the cavity. If you fold figure 1 in half (vertical fold line) you have something like a tapered microwave cavity. I don't see the need to invoke negative mass (they did say effectively) as the same description looks like the "self accelerating" particle papers.
The question is "is the nonlinearity a required condition ?".
....
Added: If nothing else, it looks like the force (acceleration) is in the right direction (toward the small end).
If I'm reading correctly, they did not (?) observe defocusing, and they would still get an effect if the negative mass was zero. (?)
quasiparticles such as electrons and holes in solid-state
crystals, massspring systems or collective excitations such as
BoseEinstein condensates in lattices may exhibit a dispersion
relation with regions of inverted curvature where the effective mass
is negative. Similarly, in photonic guiding structures, the effective
photon mass can be positive or negative depending on the sign of
the associated group velocity dispersion
This is directly analogous to a relativistic particle whose mass seems to increase during the course
of acceleration and therefore cannot exceed the velocity of light. The
hyperbolic trajectory of a constantly accelerated relativistic particle
viewed from an inertial reference frame coincides well with the
motion of our optical diametric drive (dashed white line overlaid to
Fig. 4a,b; see Supplementary Methods), thus proving the ongoing
action of the propulsion mechanism.
In contrast, when the same Gaussian
excitation excites the lower band (where the effective mass is
negative), the nonlinearity reverses its action and induces strong
nonlinear defocusing effects (Fig. 3b).
In our set-up, optical diametric drive acceleration is realized
by allowing the self-trapped wave packet of Fig. 3a to nonlinearly
interact with the defocusing beam shown in Fig. 3b. While the
positive-mass soliton is attracted by the negative-mass beam, the
latter is constantly repelled. As a result, the positive-mass beam will
permanently pursue its negative-mass counterpart while the latter
one tries to escape.
Thanks for that. But you know what they say extraordinary claims require extraordinary evidence. I'm sure if this is ever proven too a sufficient degree they'll have no problem obtaining funding.
Sometimes something extraordinary is also pretty subtle. :) Why can't even modest results that show something new be extraordinary? Perhaps extraordinary is in the intellectual flexibility of the beholder. :)
When does a skeptic's evaluation turn to "that's extraordinary?" And is that a sound benchmark to evaluate the merit?
The ESA had a study called Ariadna 04/1201 and a contract called PHOTONIMPULS ANR-09-BLAN-0088-01 to investigate Feigel's claims, derive a Lorentz invariant (and correct) description of the Feigel process, and figure out if the QV can be used for propulsion:
http://www.esa.int/gsp/ACT/ariadna/projects/ari_study_04-1201.html
http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Koln_Feigel.pdf
http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Grenoble_Feigel.pdf
About the ARIADNA study #04/1201 from the ESA, evaluating the anomalous Feigel Process for the extraction of momentum from a vacuum, I quote the conclusions of the final report (http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Koln_Feigel.pdf) (emphasis by me):QuoteOn the basis of our study, we come to the following conclusions: The derivation of the generally covariant relativistic constitutive relations for a moving magnetoelectric medium, together with the subsequent analysis of the vacuum waves travelling through the sample of a finite size shows that the magnetoelectric body will not move, despite the presence of a certain asummetry between the left- and right-moving waves in the matter. However, this only refers to the case of waves due to vacuum fluctuation.
For the real waves falling symmetrically from the two sides on a magnetoelectric body, we expect a nontrivial effect of the Feigel type. Thus, we cannot confirm the possibility of "extracting momentum from nothing".
So this study pretty much invalidated the anomalous Feigel effect when considering the QFV conjecture, aka "extraction of momentum from the virtual photons of the quantum vacuum fluctuations". It showed however that an anomalous Feigel effect could be obtained with real photons. So for a thruster, does the photons (microwaves ?) generator (magnetron ?) has to be decoupled (exterior) from the thruster or could it be part of it as in an EmDrive?
A recent publication [Phys. Rev. Lett. 92, 020404 (2004)] raises the possibility of momentum transfer from zero-point quantum fluctuations to matter, controlled by applied electric and magnetic fields. We present a Lorentz-invariant description using field-theoretical regularization techniques. We find no momentum transfer for homogeneous media, but predict a very small transfer for a Casimir-type geometry.
@ Mulletron
Great find!
Separating the two photon directions allows them to control their interaction (equivalent of the cavity taper and/or dielectric). In the EMdrive the two directions are intimately coupled within the cavity. If you fold figure 1 in half (vertical fold line) you have something like a tapered microwave cavity. I don't see the need to invoke negative mass (they did say effectively) as the same description looks like the "self accelerating" particle papers.
The question is "is the nonlinearity a required condition ?".
“PT-symmetry breaking alone is not sufficient to have nonreciprocal response; operation in the nonlinear regime is also necessary. In the linear regime, light transmission is always reciprocal regardless of whether PT-symmetry is broken or not,”
Does it have to be nonlinearity of the dielectric? Why not nonlinearity of the cavity itself?....Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?
While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.
That could be a Rosetta Stone...
Well the cavity walls may have thin films of nonlinear material on them, but I'm not entirely convinced that nonlinear behavior is absolutely necessary. The asymmetric behavior of the photon timelines may well be the fundamental factor.I can understand the asymmetry arising from nonlinearity. This paper (a really outstanding contribution by @Mulletron, who really deserves the strongest thank you for posting it)
A structure can be non-reciprocal when biased with a vector that is odd under time reversal, i.e. the magnetic field, the current, the linear momentum and the angular momentum [J. D. Jackson, Classical Electrodynamics, John Wiley & Sons, Inc., 1999].
The Onsager–Casimir principle states that any odd vector under time reversal, such as electric current and linear momentum, can also produce a non-reciprocal response.
[snip]
So from the research above on magnetoelectrics, you need a Casimir geometry:
From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.
1) For the unloaded cavity (no dielectric) the gaps where the end plates meet the frustum. Two Casimir plates in a ring, one large, one small.
2) For the loaded cavity, the above, but add in the gap between the copper and HDPE as well as the gap between the two HDPE discs.
3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.
So it seems like a good idea to sandwich some Cr2O3 in between the two HDPE discs and/or between the HDPE and the copper end plate. That's why I got a baggie of the stuff to eventually try out. I have some .5 micron in powder form and .3 micron in paste form.
http://www.creol.ucf.edu/Research/Publications/7155.pdf
[snip]
[snip]
So from the research above on magnetoelectrics, you need a Casimir geometry:
From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.
[snip]
3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.
Regarding 3): Is it thinkable that the EM-drive is a kind of large 'inverse' Casimir cavity? In the 'normal' Casimir cavity, there is a reduced virtual photon spectrum, compared to outside the cavity. However, one might argue that inside the comparably giant EM-drive cavity, there is an increased real photon spectrum for that specific spatial volume, compared to the outside of the cavity and hence a similar effect arises as would be the case for a 'normal' Casimir cavity. Does that make sense?
What do you think?
[snip]
[snip]
So from the research above on magnetoelectrics, you need a Casimir geometry:
From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.
[snip]
3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.
Regarding 3): Is it thinkable that the EM-drive is a kind of large 'inverse' Casimir cavity? In the 'normal' Casimir cavity, there is a reduced virtual photon spectrum, compared to outside the cavity. However, one might argue that inside the comparably giant EM-drive cavity, there is an increased real photon spectrum for that specific spatial volume, compared to the outside of the cavity and hence a similar effect arises as would be the case for a 'normal' Casimir cavity. Does that make sense?
What do you think?
It makes sense but the frustum cavity is so huge compared to a Casimir cavity. The Casimir force doesn't dominate in such a spacious regime.
Something that makes me think that time delay phase modulation EM propulsion is going on inside the cavity, [diametric propulsion if you want to call it that] is I remember the big plate being fairly hot like positive work was going on there and the narrow end of the cavity looked fairly cool in comparison (negative work?). If so then propulsion being toward the side doing negative work [the narrow end].The small base of NASA's Eagleworks EM Drive truncated cone is insulated by the (2.13 inches) thick polymer HDPE while the large base of the truncated cone is not insulated and it is directly exposed to induction heating.
Thanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.Agreed, outgassing (due to microwave heating of water vapor previously trapped in the HDPE or PTFE polymer dielectric) would be something to watch out for in a vacuum environment at significantly lower temperatures (near 200 deg F) than pyrolysis (>700 deg F).
This Lawrence Livermore Lab report on outgassing of water vapor from HDPE is pertinent:
Vacuum Outgassing of High Density Polyethylene
L. N. Dinh*, J. Sze, M. A. Schildbach, S. C. Chinn, R. S. Maxwell, P. Raboin, W. McLean II
Lawrence Livermore National Laboratory, Livermore, Ca, USA
https://e-reports-ext.llnl.gov/pdf/364291.pdf
It concludes that outgassing of H2O from HDPE can be significantly reduced by vacuum baking at 368 degres K
(203 deg F) for a few hours prior to device assembly.
Something that makes me think that time delay phase modulation EM propulsion is going on inside the cavity, [diametric propulsion if you want to call it that] is I remember the big plate being fairly hot like positive work was going on there and the narrow end of the cavity looked fairly cool in comparison (negative work?). If so then propulsion being toward the side doing negative work [the narrow end].The small base of NASA's Eagleworks EM Drive truncated cone is insulated by the (2.13 inches) thick polymer HDPE while the large base of the truncated cone is not insulated and it is directly exposed to induction heating.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=636341;image)
On the other hand, Prof. Juan Yang in China did not use dielectric inserts, and hence neither end of their truncated cone EM Drive was insulated. The temperature at the center of the small end (thermocouple #1) in the Chinese experiment rose much more than the temperature at the center of the big end (thermocouple #6), actually the small end experienced the highest overall temperature in the Chinese EM Drive experiments.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=622853)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=655010)
finally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
Just how significant is that to physics in general and is it something that has been theorised to happen?
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have measured spacetime contractions (after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other drives that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
Discussions about laser interferometer readigns with other types of drives (other than the EM Drive) belong in other, separate threads.
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have measured spacetime contractions (after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other drives that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
Discussions about laser interferometer readigns with other types of drives (other than the EM Drive) belong in other, separate threads.
The poster asking for a change of thread may have innocently assumed that the laser interferometer tests were performed with a similar set-up as several years ago (that resulted in null measurements): the poster may not have understood that the recent experiments that for the first time are being reported as giving confidence in these laser interferometer measurements were performed with an EM Drive.
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have measured spacetime contractions (after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other drives that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
Discussions about laser interferometer readigns with other types of drives (other than the EM Drive) belong in other, separate threads.
This is a point that really stood out for me, among the latest salvo of updates by Paul M.
It could represent a way to falsify the assertions about something really weird and novel going on inside these drives. And probably, becoming even an explanation of the observed results (e.g. by making the measured forces gravitic or space-warp related).
As a totally not-expert in this subjects, I can't say if the topic is pertinent or not to this topic. So, what's the usual approach in the forum? Do our kind hosts prefer to take such tangential -yet relevant- topics outside their parent thread? I'm also assuming the topic is still relevant to space flight, of course.
Birchoff:
"Is it possible to run the Frustum in a null configuration? If so, is that in the plans before the next report is published?"
Yes and yes. In fact it was one of the requests made by the blue ribbon panel of PhDs that NASA/EP hired to review the Eagleworks Lab's theoretical and experimental work last summer. Even if will take a new mounting arrangement to get it accomplished.
Overall though the blue ribbon panel's experimentalists appeared to be pleased with our previous and upcoming lab work. However they ripped into Sonny's QVF/MHD conjecture because it relies on the quantum vacuum being mutable and engineer-able whereas the current physics mainstream thinks that the quantum vacuum is an immutable ground energy state of the universe that can-NOT be used to convey energy or momentum as proposed by Dr. White. However they brushed aside Sonny's QVF based derivation of the Bohr hydrogen atom electron radius as a "mathematical coincidence" and didn't have a word to say what the Casimir effect and other quantum vacuum phenomenon were caused by, that can only occur only if the QV is mutable and can convey energy and momentum. So Sonny and Jerry Vera took it upon themselves last fall to increase this mathematical coincidence from one to more than 47 times as they explored the QV created atomic electron shell radii for atoms up to atomic number 7 all based on the QV being the root cause for all of it including the origins of the electron and all other subatomic particles.
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
How do I infer that the EM Drive that was used in the first experiments reported to give laser interferometer readings of spacetime contractions must have been a pillbox-shaped, short cylinder ?
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have laser interferometer readings (which they attribute to spacetime contractions after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other electromagnetic devices, including capacitors, that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
And concerning your statement that <<both drives would work very differently... so the warp drive needs it´s own thread>> that's incorrect: the EM Drive in the laser interferometer experiment didn't work "very differently", it worked in a transverse magnetic resonant mode at 1.4 GHz frequency, so you should clarify what you mean by working very differently from the EM Drives that have been discussed in this thread.
Discussions about laser interferometer experiments with other types of devices (other than the EM Drive) belong elsewhere.
TM010 RF resonant cavity ...at a 1.48 GHz rate.
How do I infer that the EM Drive that was used in the first experiments reported to give laser interferometer readings of spacetime contractions must have been a pillbox-shaped, short cylinder ?
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have laser interferometer readings (which they attribute to spacetime contractions after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other electromagnetic devices, including capacitors, that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
And concerning your statement that <<both drives would work very differently... so the warp drive needs it´s own thread>> that's incorrect: the EM Drive in the laser interferometer experiment didn't work "very differently", it worked in a transverse magnetic resonant mode at 1.4 GHz frequency, so you should clarify what you mean by working very differently from the EM Drives that have been discussed in this thread.
Discussions about laser interferometer experiments with other types of devices (other than the EM Drive) belong elsewhere.
Based on the information given by Paul March:QuoteTM010 RF resonant cavity ...at a 1.48 GHz rate.
As I posted previously in this thread, a truncated cone cannot have a TM010 mode because the electromagnetic fields in a truncated cone cannot be constant in the longitudinal direction of the cone (due to the geometry of the cone producing a focusing, attenuating effect in the longitudinal direction). Therefore when somebody describes a resonant cavity having a TM010 mode it must be a cylindrical cavity. (Or, if the analyst is describing the mode of a truncated cone analogous to a cylindrical cavity, the truncated cone must be such that the big and small bases have approximately the same diameter, because otherwise this approximate mode would be cut-off in a truncated cone).
Using the well-known equation for the frequency of a cylindrical cavity (see for example http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) , the frequency for a TM mode is:
fmnp =( c/(2 Pi Sqrt[μr εr]) ) Sqrt[(Xmn/R)^2+(p Pi / L)^2]
for TM010 we have m=0, n=1, p=0 and therefore:
D = 2 R = ( c/(Pi Sqrt[μr εr]) ) X01/f010
and since the speed of light in air is:
c/(Sqrt[μr εr]) = 299705000 m/s
and the Bessel Zero 01 is:
X01 = 2.40482555769577
and the frequency, according to Paul March was:
f010 = 1.48*10^9 Hz
We conclude that the diameter of the cylindrical resonant cavity used in these experiments was:
D = (299705000 m/s)*2.40482555769577 / (Pi * 1.48*10^9 1/s) = 0.1550 m = 6.103 inches
Hence we conclude that the RF resonant cavity used for the first successful experiments reported to give laser interferometer readings of spacetime contractions must have been a cylinder having 6.103 inches diameter.
How do I infer that the cylinder must have been short, "pillbox shaped" with a length equal or smaller than its diameter ? Because the geometry of the experimental setup previously disclosed by NASA Eagleworks does not appear to be big enough to accommodate a significantly longer cylinder:
http://upload.wikimedia.org/wikipedia/commons/9/9b/White-Juday_Warp_Field_Interferometer_Experiment.png
Perhaps Paul March could confirm what were the geometrical dimensions of the EM Drive used in these experiments, and whether or not it had a dielectric insert and if so what type of dielectric was used.
How do I infer that the EM Drive that was used in the first experiments reported to give laser interferometer readings of spacetime contractions must have been a pillbox-shaped, short cylinder ?
We should discuss these news, that NASA Eagleworksfinally observed the first spacetime contraction effects that we are fairly confident are the real deal...the laser interferometer observed spacetime contractions are being developed in a TM010 RF resonant cavity that is driving ac E-field levels over 900kV/m at a 1.48 GHz rate.
would that be a subject to ME Drive thread?
even if the underlying principle is related (quantum vaccum, etc), still, both drives would work very differently... so the warp drive needs it´s own thread, imho.
Yes, definitely a subject for this thread: "EM Drive Developments", insofar as NASA Eagleworks reports to have laser interferometer readings (which they attribute to spacetime contractions after several years of trying) by using an EM Drive (pillbox shape, short cylinder, I think, given the reported frequency and mode shape) in TM010 resonance mode to produce the measurements.
The reason why it belongs in this thread has nothing to do with the reason you state <<the underlying principle is related (quantum vaccum, etc),>>, but instead it has everything to do with the fact that to obtain the measurements they had to use an EM Drive !
It is very significant that it is only an EM Drive (rather than the other electromagnetic devices, including capacitors, that were previously tried) that finally produced a laser interferometer signal that they are confident to report as such.
And concerning your statement that <<both drives would work very differently... so the warp drive needs it´s own thread>> that's incorrect: the EM Drive in the laser interferometer experiment didn't work "very differently", it worked in a transverse magnetic resonant mode at 1.4 GHz frequency, so you should clarify what you mean by working very differently from the EM Drives that have been discussed in this thread.
Discussions about laser interferometer experiments with other types of devices (other than the EM Drive) belong elsewhere.
Based on the information given by Paul March:QuoteTM010 RF resonant cavity ...at a 1.48 GHz rate.
As I posted previously in this thread, a truncated cone cannot have a TM010 mode because the electromagnetic fields in a truncated cone cannot be constant in the longitudinal direction of the cone (due to the geometry of the cone producing a focusing, attenuating effect in the longitudinal direction). Therefore when somebody describes a resonant cavity having a TM010 mode it must be a cylindrical cavity. (Or, if the analyst is describing the mode of a truncated cone analogous to a cylindrical cavity, the truncated cone must be such that the big and small bases have approximately the same diameter, because otherwise this approximate mode would be cut-off in a truncated cone).
Using the well-known equation for the frequency of a cylindrical cavity (see for example http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) , the frequency for a TM mode is:
fmnp =( c/(2 Pi Sqrt[μr εr]) ) Sqrt[(Xmn/R)^2+(p Pi / L)^2]
for TM010 we have m=0, n=1, p=0 and therefore:
D = 2 R = ( c/(Pi Sqrt[μr εr]) ) X01/f010
and since the speed of light in air is ( http://en.wikipedia.org/wiki/Speed_of_light ):
c/(Sqrt[μr εr]) = 299700000 m/s
and the Bessel Zero for m=0, n=1 is (see http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx ):
X01 = 2.40482555769577
and the frequency, according to Paul March (see http://forum.nasaspaceflight.com/index.php?topic=36313.msg1355764#msg1355764 ) was:
f010 = 1.48*10^9 Hz
We conclude that the diameter of the cylindrical resonant cavity used in these experiments was:
D = (299700000 m/s)*2.40482555769577 / (Pi * 1.48*10^9 1/s) = 0.1550 m = 6.103 inches
Hence we conclude that the RF resonant cavity used for the first successful experiments reported to give laser interferometer readings of spacetime contractions must have been a cylinder having 6.103 inches diameter.
How do I infer that the cylinder must have been short, "pillbox shaped" with a length equal or smaller than its diameter ? Because the geometry of the experimental setup previously disclosed by NASA Eagleworks does not appear to be big enough to accommodate a significantly longer cylinder:
http://upload.wikimedia.org/wikipedia/commons/9/9b/White-Juday_Warp_Field_Interferometer_Experiment.png
Perhaps Paul March could confirm what were the geometrical dimensions of the EM Drive used in these experiments, and whether or not it had a dielectric insert and if so what type of dielectric was used.
[..]
Lastly, the Eagleworks Lab's next paper on the Q-V entitled "Dynamics of the Vacuum" will be out on the NASA NTRS internet servers just any day now. I've already provided this forum a one page abstract and introduction for this paper, but I need to agree with those that are saying that in the end analysis, the seat of all mater and space is nothing more than waves and various vortices AKA elementary particles in the Q-V. And we also think from our ongoing work that gravity is an emergent phenomenon that is nothing more than a Q-V flow field between other Q-V entities. So when the EM-Drive creates a thrust like phenomenon, what is really happening is that the EM-drive configuration is just setting up these Q-V flows via magneto-Hydro-Dynamics (MHD) like rules that translate into our 4D universe as space-time distortions or differential gravity gradients surrounding the drive.
And my parting comment tonight is from the Star Trek NTG Universe: "Engage"
Best, Paul M.
Paul, if the warp effect was only detected inside the cone topology, why is that ...
Paul, if the warp effect was only detected inside ....
you mean the little thrust being detected on the ME Drive
.. inside an ME Drive is subject to this thread. I agree.....
if we try to understand ME Drive ..
...
would that be a subject to ME Drive thread?..
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
....
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
....
Best, Paul M.
the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
Yah, the EM and ME thing is important. ME generally refers to mach effect (Woodward) mass fluctuation thrusters.
FYI: one of many...about nonlinear surface, etc.
http://www.lajpe.org/sep12/14_LAJPE_687_Gouri_Sankar_preprint_corr_f.pdf
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
...
http://arxiv.org/abs/1101.0712
http://arxiv.org/abs/1101.1174
http://www2.cnrs.fr/en/1859.htm
http://phys.org/news/2011-05-when-the-speed-of-light.html
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
Paul,
Thanks once again for posting this great information !
QUESTION 1: Is it correct to assume that the assessment of the interferometer path-length-change measurements was accomplished by looking at the Power Spectral Density at an anomalous frequency high enough away from the pink noise area (system 1/f noise, quantum 1/f noise etc.), and so clearly distinguishable from system noise occurring at frequencies close to zero?
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
QUESTION 3: Did you plot three dimensional plots to look for power peak distribution distributions looking like ring-shaped circular-waves, corresponding to path length changes associated with such frequency (in question2) ?
(http://i.stack.imgur.com/fWFL6.jpg)
QUESTION 4: Did you conduct additional tests to confirm repeatibility of the measurements?
QUESTION 5: One would expect such ring-waves to display some statistical distribution, therefore using measures of central tendency like different truncated mean measures ( http://en.wikipedia.org/wiki/Truncated_mean ) of the multidimensional power spectral density data may be particularly helpful in assessing the data (at least I have found so in assessing massive data for different problems that also involve 1/f noise)
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
Paul,
Thanks once again for posting this great information !
QUESTION 1: Is it correct to assume that the assessment of the interferometer path-length-change measurements was accomplished by looking at the Power Spectral Density at an anomalous frequency high enough away from the pink noise area (system 1/f noise, quantum 1/f noise etc.), and so clearly distinguishable from system noise occurring at frequencies close to zero?
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
QUESTION 3: Did you plot three dimensional plots to look for power peak distribution distributions looking like ring-shaped circular-waves, corresponding to path length changes associated with such frequency (in question2) ?
(http://i.stack.imgur.com/fWFL6.jpg)
QUESTION 4: Did you conduct additional tests to confirm repeatibility of the measurements?
QUESTION 5: One would expect such ring-waves to display some statistical distribution, therefore using measures of central tendency like different truncated mean measures ( http://en.wikipedia.org/wiki/Truncated_mean ) of the multidimensional power spectral density data may be particularly helpful in assessing the data (at least I have found so in assessing massive data for different problems that also involve 1/f noise)
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
Dr. Rodal:
QUESTION 1: Is it correct to assume that the assessment of the interferometer path-length-change measurements was accomplished by looking at the Power Spectral Density at an anomalous frequency high enough away from the pink noise area (system 1/f noise, quantum 1/f noise etc.), and so clearly distinguishable from system noise occurring at frequencies close to zero?
Yes it is for its around 0.660 seconds
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
Yes, the on/off cycle time was around 1.5 seconds with some uncertainty due to Windows 7.0 time outs. Need a real time operating system (RTOto clear that problem, a RTOS system we don't have.
QUESTION 3: Did you plot three dimensional plots to look for power peak distribution distributions looking like ring-shaped circular-waves, corresponding to path length changes associated with such frequency (in question2) ?
(http://i.stack.imgur.com/fWFL6.jpg)
Yes, see attached picture.
QUESTION 4: Did you conduct additional tests to confirm repeatibility of the measurements?
Yes Michael Rollins performed four additional 27,000 on/off data sets under the same 30W RF drive condition and obtained similar test results for all five cases. Mind you at 20W RF input there was only a hint of the space-time compression effect visible above the noise platform.
QUESTION 5: One would expect such ring-waves to display some statistical distribution, therefore using measures of central tendency like different truncated mean measures ( http://en.wikipedia.org/wiki/Truncated_mean ) of the multidimensional power spectral density data may be particularly helpful in assessing the data (at least I have found so in assessing massive data for different problems that also involve 1/f noise)
I will point that out to Dr. White tomorrow.
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
See Dr. White's preliminary assessment of that issue in the attached slide. Ultimately though we will be running the warp-field resonant cavity with a vacuum contained in its active volume to get rid of all possibilities of air heating problems.
Best, Paul M.
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
Paul March, have you seen this?
http://arxiv.org/abs/1101.0712
http://arxiv.org/abs/1101.1174
http://www2.cnrs.fr/en/1859.htm
http://phys.org/news/2011-05-when-the-speed-of-light.html
Mulletron:
No I hadn't but thanks for the pointers. So what to you think an asymmetric difference of ~1x10^-18 m/s in velocity of light bring to the table? That the vacuum can be differentially polarized by applied E and B-fields in a volume, in this case dc E&M fields??
Best, Paul M.
@Paul March: since the warp drive is to be considered then as ontopic in this thread, how exactly does Dr. White theories deal with time-travel to the past in superluminal speeds? I guess that would be a major point of any space travel related applications of a warp drive.
I know Mulletron. What I want to know is exactly how Dr White theory deals with superluminal speeds, which most physicists say leads to time-travel to the past and all the paradoxes that surface from that.
According to the video I showed from Dr Davis, superluminal speeds WITHOUT time-travel to the past are possible, if the light cone is tilted from 0 to 90 degrees only...
I think this question is related to spaceflight applications exactly because time travel IS an issue at relativistic velocities (to the future) and superluminal velocities (to the past, but not according to Dr Davis)
This question is probably more related to the spaceflight applications of a warp drive than the pure theoretical issues of how EM and Warp Drives work on quantum level, since the first is a result of spaceflight application while the second (which is being discussed in this thread) is not.
I know Mulletron. What I want to know is exactly how Dr White theory deals with superluminal speeds, which most physicists say leads to time-travel to the past and all the paradoxes that surface from that.
According to the video I showed from Dr Davis, superluminal speeds WITHOUT time-travel to the past are possible, if the light cone is tilted from 0 to 90 degrees only...
I think this question is related to spaceflight applications exactly because time travel IS an issue at relativistic velocities (to the future) and superluminal velocities (to the past, but not according to Dr Davis)
This question is probably more related to the spaceflight applications of a warp drive than the pure theoretical issues of how EM and Warp Drives work on quantum level, since the first is a result of spaceflight application while the second (which is being discussed in this thread) is not.
well, my guess is that CTCs are impossible and any superluminal travel (including warp drives) are impossible unless they somehow avoid travelling to the past. (I really hate the notion of timetravel to the past, although science is not based on one's preferences)
In other words, I guess the universe is probably consistent in a way that the bending of space-time geometry is impossible if it involves time travel to the past, unless you someway engineer this bending of space-time geometry in someway similar to what I understand Dr Eric Davis talked in the video above...
@LeftField: as far as I understand, having already questioned physicists I know about it, travelling to the past if you go FTL is independent of the ship not moving inside it´s own space-time (warp drive or wormholes) does not means you WILL travel back in time, but also means nothing stops you from doing so, causing all sort of causality violations.
...Excellent conclusion, @Birchoff. Concerning your question "other than re running the test under vacuum. What other tests can we run to further enhance our understanding of what is going on" in reference to the interferometer path length measurements, in addition to what they are doing and planning to do, they could also consider:
Seems a bit premature to be worried about these issues, when we don't even have a proven and accepted theory of how the devices EagleWorks are researching will work. So from my perspective I would have to say these concerns do not matter, because at this point in the research we "don't know what we don't know". Nature could have really simple solutions for all these concerns, but in the best case we have a device that seems to show that we can manipulate the vacuum into changing the length of the path light travels. We have no clue if the effect we are seeing is actually what we think it is, until further experiments are done. So the real question for me is, other than re running the test under vacuum. What other tests can we run to further enhance our understanding of what is going on.
...
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
See Dr. White's preliminary assessment of that issue in the attached slide. Ultimately though we will be running the warp-field resonant cavity with a vacuum contained in its active volume to get rid of all possibilities of air heating problems.
Best, Paul M.
I know Mulletron. What I want to know is exactly how Dr White theory deals with superluminal speeds, which most physicists say leads to time-travel to the past and all the paradoxes that surface from that.
According to the video I showed from Dr Davis, superluminal speeds WITHOUT time-travel to the past are possible, if the light cone is tilted from 0 to 90 degrees only...
I think this question is related to spaceflight applications exactly because time travel IS an issue at relativistic velocities (to the future) and superluminal velocities (to the past, but not according to Dr Davis)
This question is probably more related to the spaceflight applications of a warp drive than the pure theoretical issues of how EM and Warp Drives work on quantum level, since the first is a result of spaceflight application while the second (which is being discussed in this thread) is not.
Don't forget that the ship is not really moving at relativistic speeds: space is. Consequently, you could take a trip to Alpha Centauri in 2 days (or less with more power... who knows?), turn your ship around and observe the Earth as it was four years ago (as light has taken four years to get there - slow coach!). You could then observe Alpha Centauri as it is "now", and how people on the Earth will see it in four years.
With this type of technology, it would be possible to predict when locally past events are going to be observable from the point of view of the Earth (or any other point that the light from such events had not yet reached). For example, a ship 1 light-day out from the Earth in the right place could witness a supernova before the Earth does and then be able to return to the Earth almost instantly and tell astronomers about the incoming light wave so that they could prepare to observe it.
Proviso: I am not an expert in time travel and I also have doubts about Dr Who.
...
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
See Dr. White's preliminary assessment of that issue in the attached slide. Ultimately though we will be running the warp-field resonant cavity with a vacuum contained in its active volume to get rid of all possibilities of air heating problems.
Best, Paul M.
Thanks Paul for your excellent answers.
Concerning the likelihood of the path-length-change measurements being the result of transient air heating, were you able to monitor the transient temperature inside the cavity with embedded thermocouples (or otherwise its external temperature with an infrared thermal camera)?
If you did monitor the transient temperature, could you make that data/plots available to the public in this forum?
Thanks
I thought I would post a graphic I made of a light cone. If I am correct for normal warp the cone just flattens suggesting that the observed mote/traveler could move some maximum distance from their original location at some later time.
I would imagine a tilted warp cone might happen where space is swirling around a rotating black hole and drags objects around it. If that space reaches light speed or above then the space moving away looks like an event horizon while the space moving towards us is blue-shifted in spectrum. If the space is moving away at less than c then it should be red-shifted. In that case if one sits still in moving space then they are moving so the axis is tilted. (I guess if our space is expanding this suggest we might have tilted light cones?) I don't know that if the central axis is tilted beyond 45 degrees that the light cone would necessarily cross the plane. I would think light would appear to move at 2*c, 2=m, from an outside observer in one direction and not move at all the other direction m=0 (space is moving against it and it gets nowhere). That would suggest some distortion of our light cone but that it's not crossing the plane where the slope m = infinity.
I would think it would require infinite energy to get to warp infinity. Hopefully I'm not too far off here.
....
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
....
Best, Paul M.
....
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
....
Best, Paul M.
Issues like this (and several other practical difficulties) associated with doing this experiment in a partial vacuum, lead me to suggest to do different experiments of path length measurement, in the interim, in different inert gas environments, each having different refraction properties.
Doing the same path length measurements, but this time in different inert gas environments may serve to put to bed the issue of the interferomenter measurements being due to refraction.
http://en.wikipedia.org/wiki/Kerr_effect
http://www.sciencedirect.com/science/article/pii/S0030401814003794
attachment:
Measurement of pressure dependent nonlinear refractive index of inert gases
Á. Börzsönyi,1 Z. Heiner,1,2 A.P. Kovács,1 M. P. Kalashnikov3 and K. Osvay1,*
In the late 70's I worked for a company that made FTIR spectrometers. They use small aperture interferometers for a laser and white light source to locate the position of the moving mirror and to trigger the A/D sampling. ... The best long term stability I was able to achieve with a Digilab interferometer was +/- 40 nM shift in the laser peak wrt to the white light peak over a 24 Hr. period. That interferometer was used on the KAO. However during the test it was mounted in a covered and temperature controlled optical table. The mirror mounts were specially designed to dampen vibrations. With an air bearing Michelson interferometer (one mirror moving) the precision can be monitored. The very small phase shifts ( a few nM) measured by the Eagleworks team as the magnitude of the space-time contractions are more than an order of magnitude below the best positional accuracy a well designed interferometer is capable of. ...
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
Yes, the on/off cycle time was around 1.5 seconds with some uncertainty due to Windows 7.0 time outs. Need a real time operating system (RTOto clear that problem, a RTOS system we don't have.
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
Yes, the on/off cycle time was around 1.5 seconds with some uncertainty due to Windows 7.0 time outs. Need a real time operating system (RTOto clear that problem, a RTOS system we don't have.
We use Red Hat Enterprise MRG Realtime for our application, and the CentOS project provides a free rebuild version of the Red Hat "kernel-rt" package set which you can install. This site http://dev.centos.org/~z00dax/mrg/ has RPMs for it, but seems a little out of date - the latest RHEL kernel-rt is 3.10.58 - but the free one would probably suit your purposes. It can be a little finicky about hardware sometimes, so you'd want to take that into consideration.
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
Yes, the on/off cycle time was around 1.5 seconds with some uncertainty due to Windows 7.0 time outs. Need a real time operating system (RTOto clear that problem, a RTOS system we don't have.
We use Red Hat Enterprise MRG Realtime for our application, and the CentOS project provides a free rebuild version of the Red Hat "kernel-rt" package set which you can install. This site http://dev.centos.org/~z00dax/mrg/ has RPMs for it, but seems a little out of date - the latest RHEL kernel-rt is 3.10.58 - but the free one would probably suit your purposes. It can be a little finicky about hardware sometimes, so you'd want to take that into consideration.
An actual laboratory demonstration of a metamaterial warp drive space time would require a non-reciprocal bi-anisotropic metamaterial, in which both spatial and time reversal symmetries are broken.http://arxiv.org/abs/1009.5663
Our long term goal is to search for
the magneto-electric non-reciprocity of quantum vacuum
[21, 28], which is approximately 7 × 108 times smaller
than what we have measured. Its detection would require
fields as high as B = 15 T and E = 20 MV/m, a better
cavity with a finesse of 200 000 and a noise level corre-
sponding to the shot-noise level with an injected laser
power near 50 mW. All these performances have already
been achieved separately, but bringing them together is
obviously a very ambitious challenge.
@Paul March: since the warp drive is to be considered then as ontopic in this thread, how exactly does Dr. White theories deal with time-travel to the past in superluminal speeds? I guess that would be a major point of any space travel related applications of a warp drive.
I remember that in Starship Congress 2013 (at which Dr. White made the first talk on Day 3 – Interstellar Future (50 years +) | Saturday August 17th, 2013 - Sonny White, “Warp Field Physics: an Update” ), the talk just after Dr. White's, was by Dr Eric Davis, that was quite mind bending, where he talks about tipping the light cone in Warp Drives (I guess that would be space-time engineering just like the Warp Drive itself?) so inside it's light cone the ship is not travelling to the past and thus there is no worry of causality violations.
Is that a view that Dr White (or yourself) agree with? Or are you sure a Warp Drive will certainly result in travel to the past?
To anyone wanting to see Dr Eric Davis talk, here is the video of the full Day 3... Dr Eric Davis talk starts at 58:00.
https://www.youtube.com/watch?v=ucyBMB_PWr8
I guess it´s on-topic because it´s intimally related to the Warp Drive by Dr White.
the topic is "light cone gymnastics" (really) ;D
I thought I would post a graphic I made of a light cone. If I am correct for normal warp the cone just flattens suggesting that the observed mote/traveler could move some maximum distance from their original location at some later time.
I would imagine a tilted warp cone might happen where space is swirling around a rotating black hole and drags objects around it. If that space reaches light speed or above then the space moving away looks like an event horizon while the space moving towards us is blue-shifted in spectrum. If the space is moving away at less than c then it should be red-shifted. In that case if one sits still in moving space then they are moving so the axis is tilted. (I guess if our space is expanding this suggest we might have tilted light cones?) I don't know that if the central axis is tilted beyond 45 degrees that the light cone would necessarily cross the plane. I would think light would appear to move at 2*c, 2=m, from an outside observer in one direction and not move at all the other direction m=0 (space is moving against it and it gets nowhere). That would suggest some distortion of our light cone but that it's not crossing the plane where the slope m = infinity.
I would think it would require infinite energy to get to warp infinity. Hopefully I'm not too far off here.
When considering the use of EM-drives in the making of warp-drives the attached two papers might be of interest.
In the meantime, back to figuring out how to reliably drive an EM-drive...
Edit: You might also like to read Sonny's Warp-field Mechanics 101 and 102 articles.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf
Best, Paul M.
... If I were going to test them for what I am talking about I would take two cylindrical cavities with the radiation input of one cavity able to be phase shifted and amplified. Put the two cavities flat plates next to each other so that the imaginary magnetic field (non radiating [decaying]) overlaps. The separation would be about 1/4 lambda separation in air for the frequency chosen. My guess is the signal of one would bleed into the other cavity which would seem to push them to be matched up in phase and not perfectly out of phase %pi/2. They are supposed to be out of phase %pi/2 so you increase the phase and amplitude of the cavity that is working against the other till it seems they are properly out of phase 1/4 lambda with matching amplitude. You might install a current sensor on each cavity to make sure you know the exact current phase and amplitude. Maybe then its possible to stack the cavities on top of each other one after the other all being off in phase 0, %pi/2, %pi, 3%pi/2 ect...
Our results show that quantum vacuum in a constant magnetic field
may exert pressures, either positive or negative, which means a transfer of momentum
from vacuum to real particles or macroscopic bodies
I never really got interested in Warp drive because I considered that to be a whole other can of worms (aka not even close to being the same thing as Emdrive), not to mention the whole idea just seemed way way out there.
So I asked myself, why is Eagleworks treating their Q-thruster like it is a warp experiment? This question cropped up before when the video below surfaced a few months ago. Specifically the question and answer at 56:40.
https://www.youtube.com/watch?v=Wokn7crjBbA
So I filed that one away for later. I didn't really get it. Boy was I in for a surprise. Check out this quote:QuoteAn actual laboratory demonstration of a metamaterial warp drive space time would require a non-reciprocal bi-anisotropic metamaterial, in which both spatial and time reversal symmetries are broken.http://arxiv.org/abs/1009.5663
http://beforeitsnews.com/science-and-technology/2011/08/updated-paper-httparxiv-orgftparxivpapers10091009-5663-pdf-984797.html
There's the old PT symmetry thing all over again! The same old themes (magnetoelectrics, broken PT symmetries) which were uncovered while trying to figure out Emdrives... are there for warp drive too. As far as I can tell, the only difference between the two is whether the spacetime distortion is small and inside the ship or large and around the ship.
It is becoming clear that we need to think of the QV as a polarizable dielectric medium. Just like others have said. Even the mainstream says the QV is a dielectric. So while it is undeniable that GR and SR are correct as always, there is ample evidence which supports the notion that the classical spacetime we all know and love (flat and curved spacetime) is emergent from a more fundamental quantum chaos underneath, and that chaos can be engineered.
@Aceshigh posted a video a few days ago of the 2013 Icarus Interstellar conference day 3.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1362005#msg1362005
At the 1:31:00 mark there is a presentation by Dr. Hal Puthoff. I've always been a bit skeptical of his claims. I've read his work and took note of what he was saying but I had no evidence to suggest he might be onto something. A quick Google search reveals that he gets a bad rap from many, so that turned me away in search of my own ideas on how things work. Whether he is fully correct or not, I'm going to pay closer attention to what he has to say from now on.
Some papers we've discussed before on here, some of which were referenced in the Starship Conference presentation mentioned above:
http://arxiv.org/abs/1302.6165
http://arxiv.org/abs/1005.0131
http://arxiv.org/abs/1204.2184
This is all going to fall on experiment. The team I mentioned before who observed non-reciprocity of the velocity of light, http://arxiv.org/abs/1101.0712 predict the same for the vacuum. So if a team finds the same effect in vacuum, we might be in business.QuoteOur long term goal is to search for
the magneto-electric non-reciprocity of quantum vacuum
[21, 28], which is approximately 7 × 10^8 times smaller
than what we have measured. Its detection would require
fields as high as B = 15 T and E = 20 MV/m, a better
cavity with a finesse of 200,000 and a noise level corre-
sponding to the shot-noise level with an injected laser
power near 50 mW. All these performances have already
been achieved separately, but bringing them together is
obviously a very ambitious challenge.
They report using permanent magnets for B and a sinusoidally driven HVPS for E.
Recent discussion wrt connecting EM to warp reminded me of this. His youtube channel is amazing. I wish we had him here in this thread.
http://youtu.be/8HazOEqeae8
They report using permanent magnets for B and a sinusoidally driven HVPS for E.
Recent discussion wrt connecting EM to warp reminded me of this. His youtube channel is amazing. I wish we had him here in this thread.
http://youtu.be/8HazOEqeae8
Has this been posted here yet?
http://www.emdrive.com/
There are links and such. Some of them might be new.
The EmDrive
A New Concept in Spacecraft Propulsion
Satellite Propulsion Research Ltd (SPR Ltd) a small UK based company, has demonstrated a remarkable new space propulsion technology. The company has successfully tested both an experimental thruster and a demonstrator engine which use patented microwave technology to convert electrical energy directly into thrust. No propellant is used in the conversion process. Thrust is produced by the amplification of the radiation pressure of an electromagnetic wave propagated through a resonant waveguide assembly.
Has this been posted here yet?Not in that Wikipedia article, instead poster "Quantanew" posted the interferometer information from the NSF EM Drive thread (including the images from Paul March) in this Wikipedia article:
http://www.emdrive.com/
There are links and such. Some of them might be new.
Just the page and the links in general; nothing specific. I was just wondering if it had been posted here yet.
Just the page and the links in general; nothing specific. I was just wondering if it had been posted here yet.
I've known of the website but are those particular contents new then?
Just the page and the links in general; nothing specific. I was just wondering if it had been posted here yet.
I've known of the website but are those particular contents new then?
AFAIK, no. The links on the front page are ordered chronologically from newer at the top to older at the bottom, and the last update was on January of this year.
Is Warp Drive Real?
Ever since the sound barrier was broken, people have turned their attention to how we can break the light speed barrier. But “Warp Drive” or any other term for faster-than-light travel still remains at the level of speculation.
The bulk of scientific knowledge concludes that it’s impossible, especially when considering Einstein’s Theory of Relativity. There are certainly some credible concepts in scientific literature, however it’s too soon to know if they are viable.
Science fiction writers have given us many images of interstellar travel, but traveling at the speed of light is simply imaginary at present.
In the meantime, science moves forward. And while NASA is not pursuing interstellar flight, scientists here continue to advance ion propulsion for missions to deep space and beyond using solar electric power. This form of propulsion is the fastest and most efficient to date.
There are many “absurd” theories that have become reality over the years of scientific research. But for the near future, warp drive remains a dream.
If you would like to know more about the theories of interstellar flight, you should visit the Tau Zero Foundation. Marc Millis, a former NASA Glenn physicist, founded the organization to consider revolutionary advancements in propulsion.
Past articles of warp drive found at this location have been archived.
Nancy Smith Kilkenny, SGT Inc.
NASA's Glenn Research Center
Last Updated: April 23, 2015
Editor: NASA Administrator
Concerning "warp-drive", please notice that the following was placed today on NASA Glenn's website ( http://www.nasa.gov/centers/glenn/technology/warp/warp.html ):
Bold added for emphasis:QuoteIs Warp Drive Real?
Ever since the sound barrier was broken, people have turned their attention to how we can break the light speed barrier. But “Warp Drive” or any other term for faster-than-light travel still remains at the level of speculation.
The bulk of scientific knowledge concludes that it’s impossible, especially when considering Einstein’s Theory of Relativity. There are certainly some credible concepts in scientific literature, however it’s too soon to know if they are viable.
Science fiction writers have given us many images of interstellar travel, but traveling at the speed of light is simply imaginary at present.
In the meantime, science moves forward. And while NASA is not pursuing interstellar flight, scientists here continue to advance ion propulsion for missions to deep space and beyond using solar electric power. This form of propulsion is the fastest and most efficient to date.
There are many “absurd” theories that have become reality over the years of scientific research. But for the near future, warp drive remains a dream.
If you would like to know more about the theories of interstellar flight, you should visit the Tau Zero Foundation. Marc Millis, a former NASA Glenn physicist, founded the organization to consider revolutionary advancements in propulsion.
Past articles of warp drive found at this location have been archived.
Nancy Smith Kilkenny, SGT Inc.
NASA's Glenn Research Center
Last Updated: April 23, 2015
Editor: NASA Administrator
So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
I regard Glenn's statement as a necessary sanitary statement to answer science-fiction fans that may be unaware of the difference between R&D and actual aerospace-engineering, and therefore may have completely unrealistic short-term expectations.
So it looks like my conjecture that the device is creating some sort of spacial warp field is likely?
Whether it is creating a distortion of the space fabric of spacetime remains to be proven (hopefully they carry on their proposed experiments in vacuum to put to bed the issue of air refraction). But just to entertain your speculative question, a back-of-the-envelope analysis quickly shows that the initial distortion of spacetime would be local and insignificant compared to the distortion of spatime produced by the Earth (which is immense in comparison). There is no issues of safety related to "black holes". No. (And there are no issues of black-hole safety at CERN either).So it looks like my conjecture that the device is creating some sort of spacial warp field is likely?
IF it´s creating a sort of warp of space-time... would it be safe to use on Earth when we increase it´s thrust by several orders of magnitude? Unless the warp distortion can be kept small but strong (think of a black hole) inside the engines...
They report using permanent magnets for B and a sinusoidally driven HVPS for E.
Recent discussion wrt connecting EM to warp reminded me of this. His youtube channel is amazing. I wish we had him here in this thread.
Is the following just "defined"
β f = - h /(1 - h )
without addressing what are the conditions for this "definition" to hold, and what is the validity of this "definition" ?
and then predictive conclusions are extracted from plugging in this "definition" into the exact solution?
They report using permanent magnets for B and a sinusoidally driven HVPS for E.
Recent discussion wrt connecting EM to warp reminded me of this. His youtube channel is amazing. I wish we had him here in this thread.
Is the following just "defined"
β f = - h /(1 - h )
without addressing what are the conditions for this "definition" to hold, and what is the validity of this "definition" ?
and then predictive conclusions are extracted from plugging in this "definition" into the exact solution?
I hopped on his youtube channel and asked him. At the 40 second mark he explains what is going on but not to the detail you're looking for.
Whether it is creating a distortion of the space fabric of spacetime remains to be proven (hopefully they carry on their proposed experiments in vacuum to put to bed the issue of air refraction). But just to entertain your speculative question, a back-of-the-envelope analysis quickly shows that the initial distortion of spacetime would be local and insignificant compared to the distortion of spatime produced by the Earth (which is immense in comparison).So it looks like my conjecture that the device is creating some sort of spacial warp field is likely?
IF it´s creating a sort of warp of space-time... would it be safe to use on Earth when we increase it´s thrust by several orders of magnitude? Unless the warp distortion can be kept small but strong (think of a black hole) inside the engines...
There is no issues of safety related to "black holes". No. (And there are no issues of black-hole safety at CERN either).
...
even if the EM Drive thrust was increased to big levels?
Is it possible to calculate at which level of EM Drive thrust the local distortion of space time would be dangerous?
...
I mentioned black holes only in the sense of strong space-time warping in a small volume...
In that same sense, I would guess that despite Earth having a much stronger effect warping space time due to it´s mass, it´s spread over a large volume.
In other words... what I am thinking here is the difference between the distortion caused by a spoon of neutron star matter, weighing the same as the Everest, and Earth itself.
Earth itself has much more gravity, but it´s spread over a really big volume... while a spoon of neutron star matter equivalent to Mount Everest would condense all that space-time distortion over such a small volume...
....
Now, Paul March talked about increasing thrust to 600 N. Let´s imagine a future EM Drive with a thrust equivalent to a chemical rocket... 600 thousand N. Would that create a significant space-time distortion?
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
So it looks like my conjecture that the device is creating some sort of spacial warp field is likely?
IF it´s creating a sort of warp of space-time... would it be safe to use on Earth when we increase it´s thrust by several orders of magnitude? Unless the warp distortion can be kept small but strong (think of a black hole) inside the engines...
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
Easy solution: Divide your travel way into hops with very short warp deactivation phases to get rid of unwanted particle collection.
That's incorrect :) . The effect has been modeled at the University of Sidney. See this:
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
Easy solution: Divide your travel way into hops with very short warp deactivation phases to get rid of unwanted particle collection.
I somehow suspect thatthey issue would be self resolving as I suspect teh particles and built up debris would flow around the warp in much the same way as the wake of a ship is formed. It would tend to wrap around the craft and be left behind, much the same way that water wraps around and is left behind a submarine.
It would tend to wrap around the craft and be left behind, much the same way that water wraps around and is left behind a submarine.
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
Easy solution: Divide your travel way into hops with very short warp deactivation phases to get rid of unwanted particle collection.
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
Easy solution: Divide your travel way into hops with very short warp deactivation phases to get rid of unwanted particle collection.
I wonder if this "broom" effect is actually a blessing in disguise, the kind that would make warp drive travel actually feasible (if it exists).
One of the biggest concerns of relativistic ships is the effect of dust and particles upon the traveling ship. The faster you go, the nastier the effect of these particles upon your ship. At some speeds blue shifting converts mere radio wave photons into gamma rays hitting you all the time. Up to the point of probably limiting the speed reachable by any ship, given the fact that even the weak CMB radiation would start heating up and melting the ship after certain fraction of c is reached.
If the warp drive "focuses" the dirt and particles in the front of the ship, releasing them upon the field's deactivation, then that's maybe a solution to the problem of high energy impacts. And probably of dust up to certain grain size.
If the warp drive "focuses" the dirt and particles in the front of the ship, releasing them upon the field's deactivation, then that's maybe a solution to the problem of high energy impacts. And probably of dust up to certain grain size.
So other than what is described in the links below, is there any proof that plane waves can travel slower or faster than c in vacuum?
http://www.sciencemag.org/content/347/6224/857
http://arxiv.org/abs/1411.3987
Our work highlights that, even in free space, the invariance of the speed of light only applies to plane waves
we show a reduction in the group velocity of photons in both a Bessel beam and photons in a focused Gaussian beam. In both cases, the delay is several micrometers over a propagation distance of ~1 meter
....The speed of light in free space propagation is a fundamental quantity. It holds a pivotal role in the foundations of relativity and field theory, as well as in technological applications such as time-of-flight measurements, and radio and satellite communication. It has previously been experimentally established that single photons travel at the group velocity
We have now shown that transverse structuring of the photon results in a decrease in the group velocity along the axis of propagation. The effect can be derived from a simple geometric argument, which is also supported by a rigorous calculation of the harmonic average of the group velocity. Beyond light, the effect observed will have applications to any wave theory, including sound waves and, potentially, gravitational waves
[snip]
Look at my answer above, on what I wrote after "EDIT".
I would worry much more about particles in space being “swept up” into the warp bubble and focused into regions before and behind the ship. When your warp-driven spaceship decelerates, these particles will be released in outbursts. The forward-facing particles can be very energetic — enough to destroy anyone at the destination directly in front of you. So, if you are planning to go on a warp-drive beware that gamma ray and high energy particles may destroy any beings on the location you are trying to reach :)
Wormholes are more benign (if you can traverse them :)
Easy solution: Divide your travel way into hops with very short warp deactivation phases to get rid of unwanted particle collection.
On another topic you can title lab safety: the energy Dr white is liable to have available to curve space is less than the energy in a big fire cracker. So lets say milligrams to a gram of TNT equivalents. In short any destructive effects from warping space at the level he is capable of in the near to medium term is comparable to an office prank. :) In other words; the minor curvature distortions he can provoke are not world threatening. They aren't even building threatening. They are on the level of slightly annoying the internal OSHA and fire safety additional duty guys.
...
there should be no accumulation of massive particles or photons. also there should be no real space carry over of extra velocity. So even if there were an accumulation of matter or energy it would not be ammo for a relativistic rail gun effect. ... It seems to me that at stuff could not find the front end of the bubble let alone collect there; let alone fry stuff at the departure point or destination.
These results suggest that any ship using an Alcubierre warp drive carrying people would need shielding
to protect them from potential dangerously blueshifted particles during the journey
and any people at the destination would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for P+ region particles.
The assumptions I posted are not mine but those of Dr White when he answered critics that brought forward the particle acceleration and accumulation objections to his theory. So I am Not qualified to defend them. But Mr March certainly is. I just brought them up because it appeared the thread participants were unaware of them. :)
I am sure he will address this and this should be very interesting for all involved. :)
Yes. I saw it in a video of one of his presentations, -I think it was a couple of years ago. If I can find it I will certainly provide a link :)The assumptions I posted are not mine but those of Dr White when he answered critics that brought forward the particle acceleration and accumulation objections to his theory. So I am Not qualified to defend them. But Mr March certainly is. I just brought them up because it appeared the thread participants were unaware of them. :)
I am sure he will address this and this should be very interesting for all involved. :)
Is there a paper where Dr. White made those statements, or are they in a video you can link to?
I would like to see what he actually wrote or said on that matter.
Thanks
Yes. I saw it in a video of one of his presentations, -I think it was a couple of years ago. If I can find it I will certainly provide a link :)The assumptions I posted are not mine but those of Dr White when he answered critics that brought forward the particle acceleration and accumulation objections to his theory. So I am Not qualified to defend them. But Mr March certainly is. I just brought them up because it appeared the thread participants were unaware of them. :)
I am sure he will address this and this should be very interesting for all involved. :)
Is there a paper where Dr. White made those statements, or are they in a video you can link to?
I would like to see what he actually wrote or said on that matter.
Thanks
EDIT: Going through the videos now. I'm half way through the first video.
what videos? The one I posted or ot
her ones?
Plenty of stuff to do in the Solar System before we have the need to venture forth.
the 4 newton version of the QVPT according to calculations using the copernicus software can send a probe to alpha proxima in 29 years of flight time; including acceleration and deacceleration time.
When considering the use of EM-drives in the making of warp-drives the attached two papers might be of interest.
In the meantime, back to figuring out how to reliably drive an EM-drive...
Edit: You might also like to read Sonny's Warp-field Mechanics 101 and 102 articles.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf
Best, Paul M.
Partial success. I found a unfortunately trimmed edit of a presentation where he started to explain it. But the answer was truncated by the end of the clip.
https://www.youtube.com/watch?v=vKTgNCGhq9Y
starts at 53:46 seconds and ends before Dr White has finished his answer. However it is probable that better clips of this presentation exist. I'll look for one tomorrow.
That's a good point to make: As the hypothesized warp region is dynamically created by the dPhi/dt dynamics, there is no constant warp. Hence, the 'boost factor' is only the time averaged or integrated value of the warp. Larger amounts of particles should hence not be able to accumulate. The real operation of the drive would be much more akin to many small 'boost' periods per second, like small warp jumps. Is that correct?The paper by the University of Sidney researchers carefully examined (with numerical computations) the paths of null and massive particles with a range of initial velocities from -c to c interacting with the warp bubble travelling at a range of globally subluminal and superluminal velocities on both constant and variable velocity paths.
Even for very short journeys the energy released is so large that you would completely obliterate anything in front of you,
Dr Rodal:
It was my impression that Dr White made his defense after the critics which probably included the Sidney critques came out; But that is just my memory of it which could be faulty. I am not sure this video i found is even the one my memory is from because i remember him going into not mathematical but verbal detail as to why particle acceleration and photon blue shift were not issues with his warp drive. but it doe give a partial defense.
So here is my question to the forum: Does anyone recognize the venue that video was taken from so I can refine my search terms for google? We need a better clip than what i found.
Dr Rodal:
It was my impression that Dr White made his defense after the critics which probably included the Sidney critques came out; But that is just my memory of it which could be faulty. I am not sure this video i found is even the one my memory is from because i remember him going into not mathematical but verbal detail as to why particle acceleration and photon blue shift were not issues with his warp drive. but it doe give a partial defense.
So here is my question to the forum: Does anyone recognize the venue that video was taken from so I can refine my search terms for google? We need a better clip than what i found.
here, it´s about 4 minutes longer. You can jump to 54:00
https://www.youtube.com/watch?v=9M8yht_ofHc
As far as the issue with the warp drive gamma burst, from my understanding of the topic, the amount of build up has to do with both the average amount of particulate matter in your way (random gasses, dust motes, even possibly small rocks) and the length of time in warp. (Speed might also factor into this, but I cannot remember to be honest.) So a boost through 10,000 miles of space past lunar orbit might not have a whole lot of gamma burst to it despite the density provided from solar winds. But a boost of the full 4.2-ish light years from Alpha Centauri COULD be quite the lethal light show.
As such, it seems like one of ways we'd handle this in the early days is just a matter of protocol. Any approaches to a star system end with the arriving ship coming out of the main leg of their warp fairly off in the distance to harmlessly shove off the burst. The advised distance for this would be an 'outer warp limit'. Until more information is known about the new star system, and the nature of the gamma burst itself, it might also be advisable to attempt to come in pointed to some degree off the target systems ecliptic. Following a short period of observation (verifying your position mostly), one could make a few shorter hops as they come in, to try and keep the burst minimized. Finally, it would seem that unless the 'inner warp limit' around the destination planet was quite large, the advisable thing to do is for the arriving ship to actually come out of warp having driven PAST the planet it is attempting to reach. This ensures that regardless of gamma burst, Earth and its satellites are not in any sort of peril. Speaking of the satellites, my own recommendation for the inner warp limit would be a distance a bit beyond the current useful orbits for satellites, just to ensure we don't bombard our infrastructure with gamma bursts unnecessarily.
In the early days of warp travel, this is probably quite sufficient to deal with any issues. Though as more and more warp craft are built, some amount of effort would need to be expended to deal with orbital traffic control to ensure that an arriving ship doesn't accidentally blast a recently arrived ship.
Chances are decent we'd set up some sort of scheduled window per the ships flight plan such that once you arrive at the outer warp limit, there is a radio ready to chat with you to let you know what flight path to take in and at what time intervals.
Just my thoughts.
So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
I regard Glenn's statement as a necessary sanitary statement to answer science-fiction fans that may be unaware of the difference between R&D and actual aerospace-engineering, and therefore may have completely unrealistic short-term expectations.
The Chicago pile (the world's first artificial nuclear reactor) had no radiation shielding and no cooling system of any kind. Enrico Fermi described the apparatus as "a crude pile of black bricks and wooden timbers." It was made of a large amount of graphite and uranium, with "control rods" of cadmium, indium, and silver. The Atomic Energy Commission later noted, that the real "gamble" was conducting "a possibly catastrophic experiment in one of the most densely populated areas of the nation!"So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
I regard Glenn's statement as a necessary sanitary statement to answer science-fiction fans that may be unaware of the difference between R&D and actual aerospace-engineering, and therefore may have completely unrealistic short-term expectations.
Personally, I'm awaiting an unequivocal "Chicago Pile" moment, instead of near misses and uncertain results.
So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
I regard Glenn's statement as a necessary sanitary statement to answer science-fiction fans that may be unaware of the difference between R&D and actual aerospace-engineering, and therefore may have completely unrealistic short-term expectations.
Personally, I'm awaiting an unequivocal "Chicago Pile" moment, instead of near misses and uncertain results.
The Chicago pile (the world's first artificial nuclear reactor) had no radiation shielding and no cooling system of any kind. Enrico Fermi described the apparatus as "a crude pile of black bricks and wooden timbers." It was made of a large amount of graphite and uranium, with "control rods" of cadmium, indium, and silver. The Atomic Energy Commission later noted, that the real "gamble" was conducting "a possibly catastrophic experiment in one of the most densely populated areas of the nation!"So it looks like any interest in warp drive has been for now shelved. But then warp drive isn't the EM drive & I imagine it's possible that people were getting the two mixed up and this is an act of clarification.Your statements are of course your personal view. I regard the first statement as unwarranted speculation, as the announcement from NASA Glenn just pertains their own center's work on space propulsion, and also because NASA Eagleworks is not conducting engineering of an actual warp-drive vehicle but is instead conducting R&D interferometer tests for the purposes discussed in previous posts.
I regard Glenn's statement as a necessary sanitary statement to answer science-fiction fans that may be unaware of the difference between R&D and actual aerospace-engineering, and therefore may have completely unrealistic short-term expectations.
Personally, I'm awaiting an unequivocal "Chicago Pile" moment, instead of near misses and uncertain results.
Thus, Eagleworks probably should adopt a better analogy than the "Chicago Pile moment" :)
Perhaps we should help them find a more politically acceptable analogy :)
...What ring laser thing possessing " always transient negative energy regions in the waveform" are you referring to?
I'm thinking about that ring laser thing (from the optical diametric drive research) again where the wave form is formed in such a way that there are always transient negative energy regions in the waveform.
...
...What ring laser thing possessing " always transient negative energy regions in the waveform" are you referring to?
I'm thinking about that ring laser thing (from the optical diametric drive research) again where the wave form is formed in such a way that there are always transient negative energy regions in the waveform.
...
Link please :)
When considering the use of EM-drives in the making of warp-drives the attached two papers might be of interest.
In the meantime, back to figuring out how to reliably drive an EM-drive...
Edit: You might also like to read Sonny's Warp-field Mechanics 101 and 102 articles.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf
Best, Paul M.
Paul M,
Thanks a lot. This papers very interesting, but little old. And what about latest papers/presentations which dated 04/04/2015, 04/09/2015 and 04/15/2015. I've seen only few pages from them and it would be very interesting to read full version. Can you share full document, please. In attachment are this pages I've seen.
Best regards,
Nikita Unkovsky
When considering the use of EM-drives in the making of warp-drives the attached two papers might be of interest.
In the meantime, back to figuring out how to reliably drive an EM-drive...
Edit: You might also like to read Sonny's Warp-field Mechanics 101 and 102 articles.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf
Best, Paul M.
Paul M,
Thanks a lot. This papers very interesting, but little old. And what about latest papers/presentations which dated 04/04/2015, 04/09/2015 and 04/15/2015. I've seen only few pages from them and it would be very interesting to read full version. Can you share full document, please. In attachment are this pages I've seen.
Best regards,
Nikita Unkovsky
Nikita:
Dr. White's latest Warp Field Interferometer (WFI) results are just in PowerPoint file format at the moment, for they are just used for keeping the Eagleworks' technical and management teams aware of the latest developments. So if you want a copy of same you need to send a note to Dr. White asking for it. In the meantime Dr. White cautioned me yesterday that I need to be more careful in declaring we've observed the first lab based space-time warp signal and rather say we have observed another non-negative results in regards to the current still in-air WFI tests, even though they are the best signals we've seen to date. It appears that whenever we talk about warp-drives in our work in a positive way, the general populace and the press reads way too much into our technical disclosures and progress.
Next find attached Sonny's latest WFI data set number-1 analysis that utilizes all 28.5k period samples instead of just a very few arbitrarily selected pixel addresses we used before so as to minimize the compute times. And I'm glad that Dr. White was an ex-game programmer in his youth because his programming expertise was really needed for this problem to be able to analysis this large set in less than the 100 years his initial cut at is indicated. In fact it is now running in less than 4-to-6 hours on a Windows 7.0 PC with an Intel i5 in it. Be that as it may, you will note that the assumed in-air space-time compression signal is still there with now a much improved signal to noise ratio than the previous example I provided.
Best, Paul M.
Thank you for providing the links and refreshing my mind....What ring laser thing possessing " always transient negative energy regions in the waveform" are you referring to?
I'm thinking about that ring laser thing (from the optical diametric drive research) again where the wave form is formed in such a way that there are always transient negative energy regions in the waveform.
...
Link please :)
http://phys.org/news/2013-10-optical-diametric.html
http://www.creol.ucf.edu/Research/Publications/7155.pdf
http://www.nature.com/nphys/journal/v9/n12/full/nphys2777.html?WT.ec_id=NPHYS-201312
"Always transient" refers to the way squeezed light makes negative energy. It's always for a tiny fraction of the over all cycle and the positive side always dwarfs it. But in a circular track... there should be a tiny bit present at all times and in all parts of the track. Or maybe not as tiny as it would be in a finite length course and there are two circular stacked circular tracks in those articles. Maybe the two fields can constructively reinforce the negative components or destructively interfere with the positive portion selectively. i don't know much about the physics. I'm just "using the force."
EDIT: So here is a question I have about squeezed light. what would happen if a portion of the circular track was made to slow light down? I have read about certain research slowing light down under the SOL in a vacuum. You have two rings... one of the trackways could have unimpeded squeezed light and the other had at least a portion with a go slow zone. Could the tracks be juxtaposed in such a way that the negative regions of the waveform were close enough to sum together? And could there be a tidal pile up of negative energy caused by the go slow zone?
Speaking of establishing phenomena - does anyone have a good reference on how using an oscillating EM field is supposed to induce spacetime contractions?
I've been doing a little background reading, specifically:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936.pdf)
http://www.earthtech.org/publications/davis_STAIF_conference_2.pdf (http://www.earthtech.org/publications/davis_STAIF_conference_2.pdf)
http://members.shaw.ca/mike.anderton/WarpDrive.pdf (http://members.shaw.ca/mike.anderton/WarpDrive.pdf)
http://link.springer.com/article/10.1023%2FA%3A1026299010288 (http://link.springer.com/article/10.1023%2FA%3A1026299010288)
http://www.gravityresearchfoundation.org/pdf/awarded/2004/loup_santos.pdf (http://www.gravityresearchfoundation.org/pdf/awarded/2004/loup_santos.pdf)
I saw this plot :
Is it just to push the peak past the 1/f noise?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=825749;image[/url)
What is the latest news on the EM drive. I have looked on Google. I have just read on another website that NASA may have accidentally created a warp field? Is this true.
....
Personally, I'm awaiting an unequivocal "Chicago Pile" moment, instead of near misses and uncertain results.
....
, in the unlikely scenario that it is we will have to wait at least 6 months for any supporting evidence, and this is gaining traction with SciFi hopefuls because it is being discussed by authoritative figures (NASA employees on this forum).
....
Personally, I'm awaiting an unequivocal "Chicago Pile" moment, instead of near misses and uncertain results.....
, in the unlikely scenario that it is we will have to wait at least 6 months for any supporting evidence, and this is gaining traction with SciFi hopefuls because it is being discussed by authoritative figures (NASA employees on this forum).
long-term R&D work is like an out-of-the-money call option: the probability of success is small and conversely, the payoff is huge.
Regarding timing, it also works like an out-of-the-money call option: by the time you'll hear "an unequivocal yes, it is a success" you will be among the last to know. This applies to R&D on biotech drugs, R&D on Defense projects, R&D on high-tech, etc.
So resign yourself to the truth: nobody will-ring a bell letting you know about the "pile moment" (certainly this was not done in WWII for the Chicago pile, we didn't announce to the enemy that we had launched onto the first steps leading to the A-Bomb).
The likelihood of any particular long-term R&D project having a practical payoff is small, if there is a payoff it will be huge, and you will be the last to know :)
...
long-term R&D work is like an out-of-the-money call option: the probability of success is small and conversely, the payoff is huge.
Regarding timing, it also works like an out-of-the-money call option: by the time you'll hear "an unequivocal yes, it is a success" you will be among the last to know. This applies to R&D on biotech drugs, R&D on Defense projects, R&D on high-tech, etc.
So resign yourself to the truth: nobody will-ring a bell letting you know about the "pile moment" (certainly this was not done in WWII for the Chicago pile, we didn't announce to the enemy that we had launched onto the first steps leading to the A-Bomb).
The likelihood of any particular long-term R&D project having a practical payoff is small, if there is a payoff it will be huge, and you will be the last to know :)
Bit late in the day for people to be putting forward the line that there is nothing to see here please move along now.
?
Who put "forward the line that there is nothing to see here please move along " ?
?
Read again. Who said "unfounded in reality " ????...
long-term R&D work is like an out-of-the-money call option: the probability of success is small and conversely, the payoff is huge.
Regarding timing, it also works like an out-of-the-money call option: by the time you'll hear "an unequivocal yes, it is a success" you will be among the last to know. This applies to R&D on biotech drugs, R&D on Defense projects, R&D on high-tech, etc.
So resign yourself to the truth: nobody will-ring a bell letting you know about the "pile moment" (certainly this was not done in WWII for the Chicago pile, we didn't announce to the enemy that we had launched onto the first steps leading to the A-Bomb).
The likelihood of any particular long-term R&D project having a practical payoff is small, if there is a payoff it will be huge, and you will be the last to know :)
Bit late in the day for people to be putting forward the line that there is nothing to see here please move along now.
?
Who put "forward the line that there is nothing to see here please move along " ?
?
I meant it's a bit late in the day to be attempting to cool expectations as regards warp drives even if unfounded in reality as mention of such has already attracted the attention of the wider realm.
There is nothing wrong with regular people getting excited by this.
NASA developed a war-drive accidentally ???? ::)
NASA developed a war-drive accidentally ???? ::)
was that an intended pun because of the possibility of destroying a small civilization just by turning off the warp field while pointing the ship at the planet? :D
The article states:QuoteAnother surprise is that the discovery was accidental, as this comment attests.
"Seems to have been an accidental connection. They were wondering where this “thrust” might be coming from. One scientists proposed that maybe it’s a warp of the spacetime foam, which is causing the thrust."
There is nothing wrong with regular people getting excited by this.
as opposed to what? Are we all NASA engineers or PHDs? In fact, non PhDs, get off! ;D
Please be assured that @Stormbringer didn't mean anything of the kind. I have seen most of @Stormbringer's posts: a most considerate, polite, respectful, helpful and professional poster. The written word, particularly when typing fast, some times can convey extra meanings completely unintended by the person who wrote them in good faith.There is nothing wrong with regular people getting excited by this.
as opposed to what? Are we all NASA engineers or PHDs? In fact, non PhDs, get off! ;D
As an uneducated nitwit who studies math and physics for sport, I am deeply frustrated by the idea that people without specialized training should be excited by anything which isn't in a textbook.
There is nothing wrong with regular people getting excited by this. Just as there is nothing wrong with non jurors and so forth forming an opinion on a court case.
research that stirs the public imagination is good for science itself and the budgets thereof. ;D
it ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things. Because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new. This coolness arises partly from fear of the opponents, who have the laws on their side, and partly from the incredulity of men, who do not readily believe in new things until they have had a long experience of them. Thus it happens that whenever those who are hostile have the opportunity to attack they do it like partisans, whilst the others defend lukewarmly
So, guys.. please continue to share the R&D process so openly as you have done.
8)
So, guys.. please continue to share the R&D process so openly as you have done.
8)
On this subject, please also report, as much as possible, negative results, especially since it's still probable that there is a mundane explanation for all the strange results obtained so far.
Reporting negative results is something scientists agree is not done enough, but it's easier on this forum since we have the advantage that there is no editorial board or reviewers.
Paul M,
Are there any prepared graphics of null runs with the warp interferometry experiment?
Just as an aside; I'm sure it hasn't escaped the attention of most here that I am an uncredentialed layperson that usually goes cross eyed just looking at the math part of this. I handle most of this at a purely verbal level. And I am more willing than most here (at least temporarily) to dip into the speculative, the fringe and the Ko0ky side for bits that might have something to them. So it's not as if i am telling such people to get out. I'd be hoisting myself by my own belt loops and escorting my own self out if that were the case.
...
Sense shines with a double luster when it is set in humility. An able yet humble man is a jewel worth a kingdom.
...The induction heating through the cavity occurs at the speed of light, therefore it is practically instantaneous. The induction heating decays exponentially in the copper thickness. The skin depth of induction heating is minute: for copper at 2 GHz it is 1.46 micrometers. So the only practical issue involving time is due to thermal conduction through the copper, which is governed by the thermal diffusivity of copper and the thickness of copper. It is best discussed in terms of the dimensionless Fourier number. I have conducted a number of calculations based on this earlier on the thread and wrote a paper on thermal buckling for the cavity that has some representative numbers (less than a second to move the copper a fraction of its thickness). The bending due to the thermal gradient through the thickness is signifcantly slower, on the order of the test duration. @frobnicat and me had a number of discussions and calculations on this also earlier on the thread.
BTW, when the RF is first turned on we literally have an RF induction heating system that immediately starts warming the copper cavity walls, especially at the large OD end of the frustum. How long does that RF induced thermal heating take to start moving the copper frustum and to what degree? ..
...Forget it. You are doing enough reporting interesting results to this thread, for which we are thankful.
How does one report "negative" results when at times the acquired data just doesn't make sense? ...
...Forget it. You are doing enough reporting interesting results to this thread, for which we are thankful.
How does one report "negative" results when at times the acquired data just doesn't make sense? ...
Asking you to report all your negative results to a forum is unrealistic.
Ask those who ask you to report negative results whether they know what is the proportion of papers reporting negative results in the most respected peer-reviewed scientific journals.
...Forget it. You are doing enough reporting interesting results to this thread, for which we are thankful.
How does one report "negative" results when at times the acquired data just doesn't make sense? ...
Asking you to report all your negative results to a forum is unrealistic.
...Forget it. You are doing enough reporting interesting results to this thread, for which we are thankful.
How does one report "negative" results when at times the acquired data just doesn't make sense? ...
Asking you to report all your negative results to a forum is unrealistic.
I agree with this. Negative results don't need to be reported if a protocol has been developed that produces consistent reproducible results. No one cares about Edisons' many failed experiments while developing an electric light. In patent language this is called "reduction to practice".
Yes we all agree that documenting every detail is always better. But we have to be realistic and not insist with undue requests from the only person conducting this research that is openly discussing it (certainly Shawyer's team and Prof. Yang's team members have never directly disclosed any data or answered any questions whatsoever in this forum).
For the EM Drive we have a resonant electromagnetic cavity which according to classical physics (encompassing the theory of General Relativity as well as linear Quantum Mechanics), should not accelerate in outer space (under the action of no external forces or no external fields, assuming that the Quantum Vacuum is indestructible and immutable, involving no CP parity violation) because of the universal law of conservation of momentum. (*)
A billion tests that resulted in the EM Drive producing no acceleration will hold no attention from the scientific community, since such results are fully expected.
A reproducible, incontrovertible test showing self-acceleration (and certainly one showing levitation of the test article for anybody to see) will hold much more attention from the scientific community than a billion tests showing no acceleration.
Once you get that reproducible, consistent, incontrovertible result, one can proceed to discuss the kind of engineering development that Edison engaged in, and where negative results of variations from the reproducible, consistent, incontrovertible result are valuable in optimizing the device.
At the moment we are still seeking that reproducible, consistent, incontrovertible result.
__________________________
(*) we are not dealing here with an inexact science. This is not like Medicine, where a drug can be effective with 70% of the population, ineffective with 29% of the population and produce severe negative effects with 1% of the population. Conservation of momentum applies in physics for 100% of all cases bar none. Ditto for conservation of energy. These are universal laws, just like everybody here is subject to gravitation and we don't have a certain percentage of the population that is unaffected by gravity.
It's possible my eyes glassed over at some point, so I apologize if this has already been answered. I thought the preferred next step for Eagleworks testing was a high power, broad frequency test series, but it sounds like this plan has been shelved. What's changed, and/or has been learned?The next step remains the same: higher power and modulation. What is being discussed is what is the optimal way to achieve the desired modulation in a controlled , optimal manner, for example:
inject harmonic signals in a controlled manner into the frustum cavity that will modulate the fundamental resonant frequency established by the VCO. A setup that is able to explore this harmonic content venue with additional on-purpose modulator and monitoring equipment that will of course require more time and money.
Harmonic content will excite higher modes. X's will be (much?) larger ...
Picture shows only modulation
(No keyboard here)
Maybe stupid question... but why didn't NASA send small scale demonstrator to space? It doesn't have to be heavy (resonance chamber doesn't have to be rated for outside pressure), it doesn't have to have even energy source (it could be plugged into ISS energy grid).
Many stupid toys made it to ISS so I think something small, maybe of 1 kg weight could be sent. It would function, or not. But it would be the PROOF of usefulness.
It's about reputation. Even 0.1% risk of becoming an international laughing stock in case of experimental failure of this kind of revolutionary claim is too high. It's a prudent stance. Better crank up the (milli)Newtons beforehand ;) .
It's about reputation. Even 0.1% risk of becoming an international laughing stock in case of experimental failure of this kind of revolutionary claim is too high. It's a prudent stance. Better crank up the (milli)Newtons beforehand ;) .
They may do it secretly. All they need is to send the experiment aboard launch vehicle of some probe as sub satellite... Alternatively they may use US air force x37 spaceplane. I think it is much better and more decisive to have real space test than anything possible here in gravity well. If it doesn't function even if it functioned in vacuum chamber, then earthside test were improperly set... Or your experiment needs to be adjusted to zero gravity.
China could have thought of something similar with their EM Drive experiment. Secrecy is easy :) If it functions then you tell the tale and take gratulations, if it doesn't then you tell no one.
I remember quite imposant tests of mechanic inertial engines ... mounted on boat, on pendulum etc but everything functioned through vibrations... It wouldn't function in zero gravity.
It's about reputation. Even 0.1% risk of becoming an international laughing stock in case of experimental failure of this kind of revolutionary claim is too high. It's a prudent stance. Better crank up the (milli)Newtons beforehand ;) .
They may do it secretly. All they need is to send the experiment aboard launch vehicle of some probe as sub satellite... Alternatively they may use US air force x37 spaceplane. I think it is much better and more decisive to have real space test than anything possible here in gravity well. If it doesn't function even if it functioned in vacuum chamber, then earthside test were improperly set... Or your experiment needs to be adjusted to zero gravity.
China could have thought of something similar with their EM Drive experiment. Secrecy is easy :) If it functions then you tell the tale and take gratulations, if it doesn't then you tell no one.
I remember quite imposant tests of mechanic inertial engines ... mounted on boat, on pendulum etc but everything functioned through vibrations... It wouldn't function in zero gravity.
Can't you just test it in 2D by floating an apparatus in a pool of water or something? (suitably protecting it from the water to avoid any electrical hazards, of course)
Okay, points taken on 2,3,4 - but for point 1, why wouldn't the pendulum approach work?To do that you need a repeatable test with enough precision. As you can see from the previous messages they are trying to address repeatability by increasing the power and modulation.
Just keep cycling the power on and off until you gradually build up some large oscillation, and the thing is visibly moving from side-to-side in a significant way.
Harmonic content will excite higher modes. X's will be (much?) larger ...
Picture shows only modulation
(No keyboard here)
"X's will be (much?) larger ..."
In Dr. White's (edit) mutable Quantum-Vacuum (Q-V) conjecture, since the Q-V compression effects scale with at least the time rate of change of the E&M energy-density phi (dPhi/dt) and dphi^2/dt^2 in the resonant cavity, the input power to thrust generation scaling should be VERY non-linear until the frustum design in question is at least generating a fully collimated Q-V beam, see previous 1kW to 100kW Q-V jet simulation work. However this non-linear thrust scaling with input power may not stop at just the fully collimated Q-V beam stage, provided there are higher than 4D dimensional interactions going on that could be extracting energy from the universe's cosmological gravitational field via several proposed thermodynamic based energy harvesting cycles that this Q-V technology could open up to us.
"Picture shows only modulation"
Good point, but at the moment MHz modulations of the RF carrier is all that we can perform since it would take another set of Phased Locked Loop (PLL) controlled VCOs and 100W microwave RF amplifiers to drive AND phase control the upper harmonics of the 1,937.2 MHz carrier signal with those being 3,874.4 MHz and 5,811.6 MHz at a minimum. And at ~$6,500 each for vacuum compatible RF amps, that's not going to happen until we've already proven this concept to NASA management. Once again the Chicken and egg problem.
So at the moment we have to rely on larger amplitude MHz modulations of the 1,937.2 MHz carrier needed to generate reliable ~100uN signals, (the current sideband levels are approx. -50 dB down from the carrier). And/or we fall back on the Eagleworks' in-development 1.2 kW magnetron & waveguide teeter-totter experiment that had better replicate Roger Shawyer's first generation EM-Drive's thrust generation capabilities of at least ~16 milli-Newton. We are still looking for experimental first light date for this magnetron experiment as occurring by the end of June. Hmmm, that should also be about the same time window that we can pull a vacuum in the Warp-field Interferometer test article as well.
Best, Paul M.
To do that you need a repeatable test with enough precision. As you can see from the previous messages they are trying to address repeatability by increasing the power and modulation.
Although any sum below $100-400k could be readily obtained through something simple like a kickstarter for means of R&D (due to prior popularization of the concepts amongst sci-fi faithfuls), I'm assuming that there is a strong aversion to such methods because contributions made from the general public are likely to come with pressure to produce a tangible end-product and not simply confirm or disprove a scientific hypothesis? Judging by how lightly speculation and confirmation is being handled by Dr. White and colleagues I'm assuming the development of expectation and the pressures of it are the primary reason such avenues are unfavorable even if they could fast-track development... Basically, the last thing they want is to become the latest cold fusion incarnation. Is this an accurate assessment?
Although any sum below $100-400k could be readily obtained through something simple like a kickstarter for means of R&D (due to prior popularization of the concepts amongst sci-fi faithfuls), I'm assuming that there is a strong aversion to such methods because contributions made from the general public are likely to come with pressure to produce a tangible end-product and not simply confirm or disprove a scientific hypothesis? Judging by how lightly speculation and confirmation is being handled by Dr. White and colleagues I'm assuming the development of expectation and the pressures of it are the primary reason such avenues are unfavorable even if they could fast-track development... Basically, the last thing they want is to become the latest cold fusion incarnation. Is this an accurate assessment?
Can't you just test it in 2D by floating an apparatus in a pool of water or something? (suitably protecting it from the water to avoid any electrical hazards, of course)
Or what about hanging it like a pendulum, and then turning the power on and off to gradually make the pendulum swing from side to side?
Or what about using some sensitive torsion balance thing like Dr Stephen Lamoreaux did for his Casimir measurement experiment?
Elon Musk is aware that his first two initials are identical with the first two initials of "EM Drive" ;) , and has been aware for several years about the EM Drive work in the UK, China and the US, as well as being aware of Dr. White's research on warping spacetime. In an older interview, Musk laughed and basically said that there have been breakthroughs in the field, presumably referring to NASA’s recent work, but such technology "isn’t on SpaceX’s immediate roadmap".
Elon Musk is aware that his first two initials are identical with the first two initials of "EM Drive" ;) , and has been aware for several years about the EM Drive work in the UK, China and the US, as well as being aware of Dr. White's research on warping spacetime. In an older interview, Musk laughed and basically said that there have been breakthroughs in the field, presumably referring to NASA’s recent work, but such technology "isn’t on SpaceX’s immediate roadmap".
I noticed Space X were the conference sponsors on one of those videos featuring Dr White.
Okay, points taken on 2,3,4 - but for point 1, why wouldn't the pendulum approach work?To do that you need a repeatable test with enough precision. As you can see from the previous messages they are trying to address repeatability by increasing the power and modulation.
Just keep cycling the power on and off until you gradually build up some large oscillation, and the thing is visibly moving from side-to-side in a significant way.
Some questions and ideas.
Eagleworks can't accept donations, I think I read. Is that universally true, or just true from random people? If we were to establish "Space Flight Research Foundation", a NPO, which would buy and lend Eagleworks equipment like these vacuum-capable RF amplifiers, would that somehow fit in the rules?
Regarding amplifers: Magnetrons are cheap and dirty, microwave-oven equipment. But am I correct in saying that someone, Perhaps Paul March, said that the reason why the Chinese and Shawyer designs work, in spite of having no dielectric, is that their messy RF eliminated the need for one? Can someone explain how this might be?
My understanding is that there is increased efficiency by the use of a dielectric and a cleaner, more stable sine wave, such as that produced by a PLL, and amplified by the use of a linear amplifier using a device such as a TWT (Travelling Wave Tube), but the problem is that the capacitors used are not vacuum-proof, as they leak electrolyte at vacuum/low pressure. I don't understand why the amplifier itself, or at least the section containing the capacitors, can't be kept in a pressurized compartment.
Please don't think these are leading questions, I don't claim to be a professional. But am an interested hobbyist. I have it in my mind to produce a Shawyer-like first-gen EmDrive (i.e. without the piezoelectric compensator) constructed out of Magnesium diboride and cooled with liquid helium (yes, higher-temp superconductors would allow me to use liquid nitrogen, but coating the inside of the frustum with such a material seems to be more difficult), and drive it with a 20KW Magnetron. Yes, I know, a crude attempt, which is why I am learning more before I go about this project. My thought is that by using such a high power, I would not need very accurate or precise thrust measurement, as it should be pretty obvious if it's working, and of course I wouldn't be doing it in a vacuum.
I think Eagleworks is doing a great job, and I eagerly await the results of further tests.
Some questions and ideas.
Eagleworks can't accept donations, I think I read. Is that universally true, or just true from random people? If we were to establish "Space Flight Research Foundation", a NPO, which would buy and lend Eagleworks equipment like these vacuum-capable RF amplifiers, would that somehow fit in the rules?
Regarding amplifers: Magnetrons are cheap and dirty, microwave-oven equipment. But am I correct in saying that someone, Perhaps Paul March, said that the reason why the Chinese and Shawyer designs work, in spite of having no dielectric, is that their messy RF eliminated the need for one? Can someone explain how this might be?
My understanding is that there is increased efficiency by the use of a dielectric and a cleaner, more stable sine wave, such as that produced by a PLL, and amplified by the use of a linear amplifier using a device such as a TWT (Travelling Wave Tube), but the problem is that the capacitors used are not vacuum-proof, as they leak electrolyte at vacuum/low pressure. I don't understand why the amplifier itself, or at least the section containing the capacitors, can't be kept in a pressurized compartment.
Please don't think these are leading questions, I don't claim to be a professional. But am an interested hobbyist. I have it in my mind to produce a Shawyer-like first-gen EmDrive (i.e. without the piezoelectric compensator) constructed out of Magnesium diboride and cooled with liquid helium (yes, higher-temp superconductors would allow me to use liquid nitrogen, but coating the inside of the frustum with such a material seems to be more difficult), and drive it with a 20KW Magnetron. Yes, I know, a crude attempt, which is why I am learning more before I go about this project. My thought is that by using such a high power, I would not need very accurate or precise thrust measurement, as it should be pretty obvious if it's working, and of course I wouldn't be doing it in a vacuum.
I think Eagleworks is doing a great job, and I eagerly await the results of further tests.
Meanwhile, I became President and a Trustee of the Space Studies Institute (www.ssi.org) and we established a fund to support "Exotic Propulsion" which is named (appropriately but uninspiringly*) the "Exotic Propulsion Initiative. It is possible to donate to the fund at our website. SSI is a 501(c)3 non-profit
From this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364270#msg1364270), how do we interpret the "RF Dissipated Power" in the central caption of this slide ?
...
...
How does one report "negative" results when at times the acquired data just doesn't make sense? I've been plowing through literally hundreds of copper frustum tests over the last year with various RF tuning configurations and finding that some appear to generate nothing but spurious thermal like results as demonstrated by their positive and then negative going gradual exponential rise and fall times, others that show a very prompt signal at RF turn-on and turn-off comparable to the electrostatic force calibrator on/off slopes, overlaid with the above thermal signatures and some that fall in between. The only real way I can make sure the "thrust" plots I've been generating are real thrust signatures is to first check for a prompt signal during the first ~5 seconds before thermal effects take hold and then going into reverse thrust mode where the thrust signature opposes the thermal signature to the point it goes negative like the one I've already appended but repeat it here. Any other testing approaches to cull out these blasted thermal signatures would be appreciated.
BTW, when the RF is first turned on we literally have an RF induction heating system that immediately starts warming the copper cavity walls, especially at the large OD end of the frustum. How long does that RF induced thermal heating take to start moving the copper frustum and to what degree? Looks like another COMSOL problem that will take into account the specific heat of all the frustum components, then profiles the resulting differential temp rise of cone that then generates a frustum expansion rate that will then have to feed into a model of the torque pendulum's deflection sensitivity to off axis loading. Yuck!
Best, Paul M.
From this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364270#msg1364270), how do we interpret the "RF Dissipated Power" in the central caption of this slide ?
...
WELCOME BACK @frobnicat !!!
We missed you ! :)
A bit of history might also be enlightening. Paul will have to remind me on the dates, but before he and Sonny established Eagleworks at NASA JSC, the two of us and myself actually set it up as a small R&D company, which I funded for about a year. Unfortunately, I couldn't keep up the support required, and after Sonny was awarded his PhD, thankfully JSC found funding and facilities for them to use to keep the dream alive. Meanwhile, I became President and a Trustee of the Space Studies Institute (www.ssi.org) and we established a fund to support "Exotic Propulsion" which is named (appropriately but uninspiringly*) the "Exotic Propulsion Initiative. It is possible to donate to the fund at our website. SSI is a 501(c)3 non-profit and thus contributions are tax-deductiable. Targeted contributions go almost 100% to the named projects since we have very modest overhead costs (we don't pay salaries to our volunteer staff, for example).
SSI is currently supporting the work of Prof. Woodward, but it has always been our intent to expand the base of researchers as resources permit. At the moment about the best we can do is to buy equipment and fund the occasional student intern, rather than pay for principal investigator labor, but that could be enough to help out more than one lab, JSC Eagleworks included. So no need to set up another organization to help – we are here and willing to be involved if the need can be articulated.
Now back to your regularly scheduled programming...er, discussion...which has been very enjoyable to follow!
(*I think I made that word up.)
Thank you so much for this! I asked this Question almost a year ago, and have been wondering about it ever since the microwave version of the EM drive came out years ago.The answers in http://physics.stackexchange.com/questions/129799/wavelength-and-frustum-shaped-resonant-cavity are incorrect regarding your question of a closed truncated cone resonating with standing electromagnetic waves. (Obviously electromagnetic resonance must obey Maxwell's equations, and it does not correspond to acoustic resonance).
http://physics.stackexchange.com/questions/129799/wavelength-and-frustum-shaped-resonant-cavity
A bit of history might also be enlightening. Paul will have to remind me on the dates, but before he and Sonny established Eagleworks at NASA JSC, the two of us and myself actually set it up as a small R&D company, which I funded for about a year. Unfortunately, I couldn't keep up the support required, and after Sonny was awarded his PhD, thankfully JSC found funding and facilities for them to use to keep the dream alive. Meanwhile, I became President and a Trustee of the Space Studies Institute (www.ssi.org) and we established a fund to support "Exotic Propulsion" which is named (appropriately but uninspiringly*) the "Exotic Propulsion Initiative. It is possible to donate to the fund at our website. SSI is a 501(c)3 non-profit and thus contributions are tax-deductiable. Targeted contributions go almost 100% to the named projects since we have very modest overhead costs (we don't pay salaries to our volunteer staff, for example).
SSI is currently supporting the work of Prof. Woodward, but it has always been our intent to expand the base of researchers as resources permit. At the moment about the best we can do is to buy equipment and fund the occasional student intern, rather than pay for principal investigator labor, but that could be enough to help out more than one lab, JSC Eagleworks included. So no need to set up another organization to help – we are here and willing to be involved if the need can be articulated.
Now back to your regularly scheduled programming...er, discussion...which has been very enjoyable to follow!
(*I think I made that word up.)
I am sorry I don´t know by name more people there, but I was surprised and happy to see Prof. Freeman Dyson on the board of trustees of an organization funding ME research and possibly if everything goes right, also EM research.
(Paul March says both are possibly two sides of the same coin, so it cracks me up ME and EM are mirrored acronyms! ;D)
....I became President and a Trustee of the Space Studies Institute (www.ssi.org) and we established a fund to support "Exotic Propulsion" which is named ....SSI is currently supporting the work of Prof. Woodward, but it has always been our intent to expand the base of researchers as resources permit. ...
....I became President and a Trustee of the Space Studies Institute (www.ssi.org) and we established a fund to support "Exotic Propulsion" which is named ....SSI is currently supporting the work of Prof. Woodward, but it has always been our intent to expand the base of researchers as resources permit. ...
Mr. Hudson,
Thanks so much for that great post. It would be interesting to know whether Prof. Freeman Dyson knows about Prof. Woodward's work (*) on the Mach Effect and/or about Dr. White's work on a mutable and degradable Quantum Vacuum, and if he does, what does Prof. Dyson think about those conjectures. I have tried to find out in the literature and I don't see anything that Dyson has published in this regard.
I did see that Dyson wrote that he believed that NASA's big and visible projects, the Shuttle and the Space Station, will in the future "appear as quaint and misguided gargantuan ventures in the wrong direction, the von Hindenbergs and Titanics of the late 20th century" and that manned spaceflight will use new launch technologies that will make chemical rockets seem absurdly inefficient.
_______________
(*) I cannot assume necessary agreement, since for example, Prof. Freeman Dyson wrote in his paper "Pilgrims, Saints, and Spacemen" that he disagreed with G.K. O'Neill on the economic viability of some of O'Neill's concepts. This although they were great partners, as proven by the fact that O'Neill asked Freeman Dyson to carry on the responsibilities of the Space Studies Institute.
SSI is currently supporting the work of Prof. Woodward, but it has always been our intent to expand the base of researchers as resources permit. At the moment about the best we can do is to buy equipment and fund the occasional student intern, rather than pay for principal investigator labor, but that could be enough to help out more than one lab, JSC Eagleworks included. So no need to set up another organization to help – we are here and willing to be involved if the need can be articulated.
Now back to your regularly scheduled programming...er, discussion...which has been very enjoyable to follow!
(*I think I made that word up.)
I am sorry I don´t know by name more people there, but I was surprised and happy to see Prof. Freeman Dyson on the board of trustees of an organization funding ME research and possibly if everything goes right, also EM research.
(Paul March says both are possibly two sides of the same coin, so it cracks me up ME and EM are mirrored acronyms! ;D)
Hello all, as one of the commenters earlier in this thread suggested, I am one of the many Reddit users that has found amazing fascination in this thread. While I have no scientific opinions to add to this conversation, and while 85% of the conversations I've read through here have done well to send me into a swath of migraines and feelings of utter intellectual inferiority, I have one things to say. Thank you. Though I may not understand much of what is being tossed back and forth here, what I do understand, has done so much to increase my excitement and astonishment of the science that is happening. Please, keep this conversation going. I look forward to reading (what I can) and keeping up with what you are doing, hypothesizing, and proofing with all subjects related to this EM drive.
And, sorry if I sound insistent, but the vertical scale variability + apparent inconsistency of stiffness (wrt known parameters) needs really to be addressed and settled one day or another, especially since we see contradictory data when the balance is used in reverse (180° turn of test article that should yield same deflection magnitudes to the left or to the right, assuming same thrusts magnitudes). A central aspect of the pendulum appears to be not properly characterised. Having to rely only on calibration pulses and proportionality is not satisfactory, given the unusual physics involved and the general scepticism, everything must fit. If one were told that a scale had 10cm long arms, but dynamics (oscillation periods) showed it was rather 1m long arms, the fact that this wont change the end result (equal weight on the plates...) is not satisfactory, there would still be a 1 order of magnitude unexplained aspect at the heart the experiment.
(http://upload.wikimedia.org/wikipedia/commons/2/24/Eo-scale_of_justice.gif)
Thanks for the regular feedbacks and open stance.
....All of the examples shown in the YouTube video attached above involve:
Lets this be warning how could be earthside test deceiving. https://www.youtube.com/watch?v=QJcbe8P5900 (https://www.youtube.com/watch?v=QJcbe8P5900) balance test is at the end of video. Of course none of this would function in zeroG.
(*) And of course, the International Space Station and near-Earth satellites are also under near the same gravitational force as the gravitational force present at the surface of the Earth, the main difference is that the ISS and satellites are in free-falling orbits. Performing an experiment inside the ISS is identical to performing an experiment inside a free falling elevator, near the surface of the Earth, the difference is the practical duration of the experiment.
(*) And of course, the International Space Station and near-Earth satellites are also under near the same gravitational force as the gravitational force present at the surface of the Earth, the main difference is that the ISS and satellites are in free-falling orbits. Performing an experiment inside the ISS is identical to performing an experiment inside a free falling elevator, near the surface of the Earth, the difference is the practical duration of the experiment.
An alternative would be to perform the experiment on one of NASA's Reduced Gravity Program aircraft (aka the vomit comet, one of the best nicknames I've come across.) The difficult remains, however, that getting space aboard for an experiment would likely require more confirmation from their existing experiments.
Hi clever people :)
So, we'll have our article on the EM Drive - expertly and patiently built by Dr. Rodal and subedited by my assistant editor Chris Gebhardt - published on Wednesday.
==snip==
From this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364270#msg1364270), how do we interpret the "RF Dissipated Power" in the central caption of this slide ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826537;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826536;image)
Is it the (DC) power input to RF amplifier ? Or the difference of RF power input to frustum minus reflected power back to amplifier ? What is measured exactly ? What is horizontal scale, is the != 0 part 16.5s long like the power-on period of the thrust chart ? Why this particular profile with initial spike and 2 plateaus ? Why don't we see a corresponding 3x magnitude "step" on the thrust chart at half the excitation time ?
I'm not sure how to interpret the next one either :
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826539;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826538;image)
Is it to say that when the spectrum is broader the initial slope on thrust chart is steeper ? On most other charts ~10s of power-on is enough to reach a plateau (kind of), why isn't it the case here ? Seems to me this is magnitude of plateau vs spectrum width that would be relevant, not slope, too much noise on top of those transients. For instance, the decay after power-off looks like having a significantly longer time constant with the richer spectrum, is it relevant ?
I have a probably rather naive question:Using MASER technology is an interesting idea.
As far as I understand, we are trying to get the microwaves resonate within the copper device, similar to blowing a pipe by more or less accurately finding the resonance frequency with our emitters, which are generating scattered waves. Would we get more refined or different results, if we could MASER's instead?
Please remember that our copper frustum has a baked on silicone PCB anti-oxidation ~0.001" thick coating on its interior surfaces to keep the copper surfaces from oxidizing and thus lowering its Q-factor over time.
What kind of earth-side experiment can be done to very tangibly and visibly demonstrate that the effect exists?One where the test apparatus is timer operated, battery powered and entirely enclosed in a permalloy-shielded, hermetically sealed container, and where there are no on-going (and changing) zero drifts of greater magnitude than the claimed forces, would demonstrate it far more tangibly than what has been done so far.
...Why is all research so focussed on the powered thrust, rather than on the increasing opposite-direction acceleration ...We need to clarify this point. My understanding is that NASA Eagleworks calls "thrust" the force occurring in the same direction as the acceleration.
From this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364270#msg1364270), how do we interpret the "RF Dissipated Power" in the central caption of this slide ?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826537;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=826536;image)
...
"How do we interpret the "RF Dissipated Power" in the central caption of this slide ? Is it the (DC) power input to RF amplifier ? Or the difference of RF power input to frustum minus reflected power back to amplifier ? "
Simple, it's the forward RF power being dissipated in the RF load AKA resonant cavity, minus the reflected power being dissipated back in the RF amplifier's 50 ohm isolator load. We measure it with two Mini-Circuit -50dBm to +20dBm RF power modules attached to the forward and reflected ports on a -40dB down bidirectional coupler.
"What is horizontal scale, is the != 0 part 16.5s long like the power-on period of the thrust chart ?
The LabView RF power meter graphics has a scrolling data logging output with time on the horizontal x-axis and RF power level on the y-axis. Since a full frame of the time axis takes about 3.5 minutes to scroll from right to left, there are no time units appended.
"Why this particular profile with initial spike and 2 plateaus ?"
Because I was manually controlling the VCO frequency to maintain the minimum VSWR, which at times is a bit jerky, being that my control servo loops are not as good as they used to be. :)
"Why don't we see a corresponding 3x magnitude "step" on the thrust chart at half the excitation time ?"
Overcoming the Inertia of the torque pendulum load which is close to 10 kg.
Hi clever people :)
So, we'll have our article on the EM Drive - expertly and patiently built by Dr. Rodal and subedited by my assistant editor Chris Gebhardt - published on Wednesday. We'll link in this thread and also have a standalone thread (the latter allowing people to get up to speed - an entry level thread as such, before braving this 104 page, 470,000 viewed thread).
I've been following this thread the best I can and I have to say that while I'm proud I know my way around a RS-25 engine, this thread has proven I probably didn't pay as much attention in class as I should have! The encouraging thing is, while NASA has become somewhat "social media fluffy" and has lost a lot some of its focus of late, there's obviously less publicized areas, such as Eagleworks, that are the true essence of Bruce Willis' line in Armageddon, where he claims "You're NASA, you're geniuses. I bet you've got a room of people just thinking *stuff* up, and people backing them up!" :)
What I was referring to is how in most of your graphs, after you turn your test article off, the graph shows a rising force acting in the opposite direction to the force you got when the device was turned on....Why is all research so focussed on the powered thrust, rather than on the increasing opposite-direction acceleration ...We need to clarify this point. My understanding is that NASA Eagleworks calls "thrust" the force occurring in the same direction as the acceleration.
Now, what does "thrust force" mean in this context? For NASA Eagleworks it means the measured displacement, that can be converted to a rotational angle of the torsional balance, and hence to a torque (knowing the torsional stiffness of the torsional balance). Or simply, force=displacement*stiffness . Like in a spring, for example. Now, this is a tautology, as the "thrust force" is entirely based on the displacement, and hence it is not surprising that the displacement should be in the same direction as the acceleration (the second order derivative of the displacement with respect to time). (And yes, forces are never directly measured, they are an intuitive and theoretical concept, what we do is measure displacements and obtain forces if we know the stiffness, or we measure accelerations and we obtain forces using F=m*a)
I am aware that Roger Shawyer has written that the thrust force and the displacement in his measurements occur in different directions, and that the EM Drive must be already in motion (or something to that effect), but frankly what he wrote in this regard is not comprehensible to me (and from what I recall was not comprehensible to @frobnicat either). Apparently it was not comprehensible to other people either, as his latest report http://www.emdrive.com/EmDriveForceMeasurement.pdf addresses this (I find his latest report just as difficult to reconcile).
In the chart below, he even refers to a "force direction" which can be in the same direction as what he calls "thust" or what he calls "reaction" occurring in the opposite direction to what he calls "thrust".
For his Demonstrator engine, he claims (in the chart below) that he measured "forces" in opposite directions for this same device. (It this was due to placing a dielectric at opposite ends or due to running the device in different mode shapes at different frequencies, I don't know.)
Thing is, the pendulum arm with its 10kg is usually not that shy of steep responses (on µm scale) from steep excitations, typically below 3s time constant. So this is strange that we don't see a corresponding step in thrust to the step from plateau to plateau of power (each during almost 8s). Why change of excitation power would deserve more "inertial smoothing" than on/off power steps ?
Also this thrust chart happens to be very clean, with low noise. There is a slight inflection at ~2/3 of excitation time but it's quite clear there's nothing as dramatic as the usual responses to excitation steps. Such a weak response when going from 1W to 3W compared to when going to or from 0W would indicate strong non linearities...
Or that what counts is not the net dissipated power in frustum (forward minus bounced back) but only forward power (regardless of what is bounced back). How could that be ?
You are referring to a drifting baseline for the measured displacement.
What I was referring to is how in most of your graphs, after you turn your test article off, the graph shows a rising force acting in the opposite direction to the force you got when the device was turned on.
edit: to clarify, this:
(http://i.imgur.com/e365fIc.jpg)
When a mirror reflects light, it experiences a slight push. This radiation pressure can be increased considerably with the help of a small superconducting island. This was revealed by the joint research done in the Aalto University and the Universities of Jyväskylä and Oulu. The finding paves a way for the studies of mechanical oscillations at the level of a single photon, the quantum of light. The results of the research were published in Nature Communications in April.
Coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of photons is a promising platform for investigations of quantum–mechanical properties of motion. A drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength. A novel scenario is to introduce into the setup a quantum two-level system (qubit), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities. Here we present a design of cavity optomechanics in the microwave frequency regime involving a Josephson junction qubit. We demonstrate boosting of the radiation–pressure interaction by six orders of magnitude, allowing to approach the strong coupling regime. We observe nonlinear phenomena at single-photon energies, such as an enhanced damping attributed to the qubit. This work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion.
...
What I was referring to is how in most of your graphs, after you turn your test article off, the graph shows a rising force acting in the opposite direction to the force you got when the device was turned on.
edit: to clarify, this:
(http://i.imgur.com/e365fIc.jpg)
We found that this slope change after the test article and RF amplifer were turned on for 10-to-20 seconds was apprently due to IR radiation from the amplifier's heatsink that is mounted on the back side of the torque penlulum on an 8" square platform was affecting the top C-flex bearing more than the lower one. We tried aluminum shielding the top bearing assembly from the heatsink IR source and managed to reverse the metioned thermal slope in the thrust plots, but after shielding the bottom one we could reduce it but still coundn't completely get rid of this thremal drift artifact. Currently we are just living with it.
Well, I have to admit I was being rather cheeky. To me, this "drift" (which did still exist in the vacuum) is a definite indication that there are experimental errors that are larger than the measured force.You are referring to a drifting baseline for the measured displacement.
What I was referring to is how in most of your graphs, after you turn your test article off, the graph shows a rising force acting in the opposite direction to the force you got when the device was turned on.
edit: to clarify, this:
(http://i.imgur.com/e365fIc.jpg)
It is addressed (succintly) in the "Anomalous..." report text in reference to thermal effects, and in multiple posts of @Star-Drive, @frobnicat and @zen-in in the EM Drive threads 1 and 2.
Nice find, I think this one is utterly damning for any hope that the experimental set up is working correctly.
More problematic than those long lasting slow drifts in rest position after power on/off, is the fact that there seem to exist a continuum of situations in between slowly evolving charts (in response to excitation steps) and steep responses that serve as proof of real thrusts on the argument of their steepness (sorry for the poor wording). For instance, the rise and decay of the chart below (obtained in vacuum) show a very different time constant to reach and leave the "thrust" plateau than with the electrostatic calibration pulses with their clean square force(t) profile. The smoothed rise could be explained by change of tuning (effective received power) of the cavity, needing a "warm-up". But the smoothed decay is really a showdown. Off is off, there is no "warm-down" time to speak of for EM radiation to disappear (on the order of µs, given size and Q factor), and no electromagnetic/quantum theory could explain such a delay unless the vacuum is as heavy and viscous as oil or water. This lag in the decay, most visible in this particular chart, was already noticed by other contributors (sorry, can't remember).
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=636345;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634625;image)
from this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326997#msg1326997)
Well, I have to admit I was being rather cheeky.
...
What bothers me the most about this research is that there is a perfectly simple and rather cheap way to screen out most of such effects. The test article needs to be powered off a battery, run from a timer, and be enclosed in a conductive box with permalloy shielding; hanging off a very very Cavendish style torsion pendulum (which is fairly insensitive to shifts in CoM as well, by the way).
...
Well, one shouldn't even see a drift the size of the measured force, when it's not even sub-micronewton range.Heat transfer, thermal expansion, thermal stress analysis for uncoupled and for coupled problems, in static and dynamic problems of complicated geometry and materials can be analyzed and modeled with Finite Element analysis (NASTRAN, ANSYS, ABAQUS, ADINA, COMSOL, etc.), just like rockets, spacecrafts and military and commercial aircraft have been analyzed for decades.
If one is heating metal, one is probably heating it unevenly, and it bends as long as heat is applied (the hotter material expands more), with a fairly short time constant (because the temperatures will equalize quickly once the heat source is off). Then the heat gets slowly conducted to another structural element, and that structural element happens to bend in a way that influences the experiment in the other direction.
How much each structural element will bend will depend to how tight the screws are tightened, what stresses are already in the metal, and so on and so forth; it's essentially impossible to account for.
The issue for analyzing thermal structural effects (and other effects) for the EM Drive project at NASA Eagleworks is not a matter of present ability to be analyzed but is, instead, a matter of scarcity of project resources (money, time, and personnel) to analyze them. For example, NASA's EM Drive truncated cone was made by Paul March himself in Paul March's wife dining room. NO TAXPAYER's tax $$$ involved in its construction.
....
This may seem dumb, but why not set up a Kickstarter for this? ..
....
This may seem dumb, but why not set up a Kickstarter for this? ..
See this great post: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364627#msg1364627
by the present President (as well as a Trustee) of the renowned Space Studies Institute (www.ssi.org) which was originally founded by G.K. O'Neill
....
This may seem dumb, but why not set up a Kickstarter for this? ..
See this great post: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364627#msg1364627
by the present President (as well as a Trustee) of the renowned Space Studies Institute (www.ssi.org) which was originally founded by G.K. O'Neill
So if I'm reading this correctly, what we need to do is set up a Kickstarter to donate money to ISS's exotic propulsion funds, which can then in turn be given to Eagleworks ;D
Speaking of NASA, I wonder why they have just archived all previous articles about hypothetical advanced propulsion systems on their official site ...
....
This may seem dumb, but why not set up a Kickstarter for this? ..
See this great post: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364627#msg1364627
by the present President (as well as a Trustee) of the renowned Space Studies Institute (www.ssi.org) which was originally founded by G.K. O'Neill
So if I'm reading this correctly, what we need to do is set up a Kickstarter to donate money to ISS's exotic propulsion funds, which can then in turn be given to Eagleworks ;D
I am not sure, but I guess that they would not be able to accept donations/kickstarters to a particular project. I guess they can accept money but the distribution of the total sum is decided by them?
which would maybe somehow prevent the exact thing that makes NASA not accept donations/kickstarters.
we established a fund to support "Exotic Propulsion" which is named (appropriately but uninspiringly*) the "Exotic Propulsion Initiative. It is possible to donate to the fund at our website. SSI is a 501(c)3 non-profit and thus contributions are tax-deductiable. Targeted contributions go almost 100% to the named projects since we have very modest overhead costs (we don't pay salaries to our volunteer staff, for example).
Speaking of NASA, I wonder why they have just archived all previous articles about hypothetical advanced propulsion systems on their official site ...
I believe that's just the warp drive related articles.
Dr. Rodal,
The 0.65Hz frequency shift of light with the new experiment is very interesting, but it was pointed out to me that air has a refraction index of 1. I take it the refraction ndex of the air involved was taken into account for this interferometer test, or that it was conducted in a vacume?
Over 27,000 cycles of data (each 1.5 sec cycle energizing the system for 0.75 sec and de-energizing it for 0.75 sec) were averaged to obtain a power spectrum that revealed a signal frequency of 0.65 Hz with amplitude clearly above system noise. Four additional tests were successfully conducted that demonstrated repeatability.
One possible explanation for the optical path length change is that it is due to refraction of the air. The NASA team examined this possibility and concluded that it is not likely that the measured change is due to transient air heating because the experiment’s visibility threshold is forty times larger than the calculated effect from air considering atmospheric heating.
Encouraged by these results, NASA Eagleworks plans to next conduct these interferometer tests in a vacuum.
Dr. Rodal,
The 0.65Hz frequency shift of light with the new experiment is very interesting, but it was pointed out to me that air has a refraction index of 1. I take it the refraction ndex of the air involved was taken into account for this interferometer test, or that it was conducted in a vacume?
1) Air does not have a refractive index of 1. The refractive index of air is approximately 1.000293. As you know air is composed of several gases:
Pure Gas Name Symbol Mole fraction
Nitrogen N2 0.78084
Oxygen O2 0.209476
Argon Ar 0.00934
Carbon Dioxide CO2 0.000314
Neon Ne 0.00001818
Methane CH4 0.000002
Helium He 0.00000524
Krypton Kr 0.00000114
Hydrogen H2 0.0000005
Xenon Xe 0.000000087
The issue involving air refraction is dealt was raised in this paper by Lee and Cleaver from Baylor University:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
See the above paper for background.
2) The 0.65 Hz frequency you are referring to is not a "frequency shift of light".
Period of energizing/de-energizing: T=0.75s+0.75s=1.5s, f=1/T=0.66 Hz ~ 0.65Hz
3) Quoting from the article:QuoteOver 27,000 cycles of data (each 1.5 sec cycle energizing the system for 0.75 sec and de-energizing it for 0.75 sec) were averaged to obtain a power spectrum that revealed a signal frequency of 0.65 Hz with amplitude clearly above system noise. Four additional tests were successfully conducted that demonstrated repeatability.
One possible explanation for the optical path length change is that it is due to refraction of the air. The NASA team examined this possibility and concluded that it is not likely that the measured change is due to transient air heating because the experiment’s visibility threshold is forty times larger than the calculated effect from air considering atmospheric heating.
4) Concerning this experiment please refer to previous posts by Star-Drive, myself, @zen-in and others
...No insult was taken 8) .
No insult was intended or directed, as I said, this waas a point made by someone else to me, and I pretty much figured that this had been taken into account, otherwise it would not have been above backgroound "noise".
Again, congratulations on what appears to be a most auspicious achievement!
All life is an experiment. The more experiments you make the better.
I am somewhat curious as to why AM modulation would increase the drives output. Is it possible that the modulation scheme is increasing the average power output, or is something else in play.
I'm wondering what it would do with pulsed RF at a high rep rate?
...No insult was taken 8) .
No insult was intended or directed, as I said, this waas a point made by someone else to me, and I pretty much figured that this had been taken into account, otherwise it would not have been above backgroound "noise".
Again, congratulations on what appears to be a most auspicious achievement!
If it appears that way, due to my cold, abrupt, way to answer the question, with references and quotations, it is due to the fact that I feel compelled to address this technically, carefully, and factually, because several other people are reading this as well, and it is important to avoid misinterpretations.
Particularly in view of the shocking "news" that have been posted in fringe sites referring to this thread, talking about NASA finding by accident how to warp space and secretly working on a Star-Trek Enterprise. :)
Actually, I thank you for your question, as it gives me the opportunity to clarify these matters.
Concerning whether a signal is or is not above "noise", that is not a trivial assessment, as randomness is ultimately undefinable. What appears random to one observer may not appear random to another. An encrypted message is a good example of this fact.
More, finer, experiments are needed.Quote from: Ralph Waldo EmersonAll life is an experiment. The more experiments you make the better.
...No insult was taken 8) .
No insult was intended or directed, as I said, this waas a point made by someone else to me, and I pretty much figured that this had been taken into account, otherwise it would not have been above backgroound "noise".
Again, congratulations on what appears to be a most auspicious achievement!
If it appears that way, due to my cold, abrupt, way to answer the question, with references and quotations, it is due to the fact that I feel compelled to address this technically, carefully, and factually, because several other people are reading this as well, and it is important to avoid misinterpretations.
Particularly in view of the shocking "news" that have been posted in fringe sites referring to this thread, talking about NASA finding by accident how to warp space and secretly working on a Star-Trek Enterprise. :)
Actually, I thank you for your question, as it gives me the opportunity to clarify these matters.
Concerning whether a signal is or is not above "noise", that is not a trivial assessment, as randomness is ultimately undefinable. What appears random to one observer may not appear random to another. An encrypted message is a good example of this fact.
More, finer, experiments are needed.Quote from: Ralph Waldo EmersonAll life is an experiment. The more experiments you make the better.
Thanks, I was hoping I hadn't stepped beyond the bounds of propriety.
Out of curiosity, what is the approximate ratio of watts to newtons, or millinewtons as the case may be, that you've been able to produce on the average?
Sad this site is indulging in quackery. Oh well.
....
This may seem dumb, but why not set up a Kickstarter for this? ..
See this great post: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364627#msg1364627
by the present President (as well as a Trustee) of the renowned Space Studies Institute (www.ssi.org) which was originally founded by G.K. O'Neill
So if I'm reading this correctly, what we need to do is set up a Kickstarter to donate money to ISS's exotic propulsion funds, which can then in turn be given to Eagleworks ;D
I am not sure, but I guess that they would not be able to accept donations/kickstarters to a particular project. I guess they can accept money but the distribution of the total sum is decided by them?
which would maybe somehow prevent the exact thing that makes NASA not accept donations/kickstarters.Quote from: HMXHMX http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364627#msg1364627we established a fund to support "Exotic Propulsion" which is named (appropriately but uninspiringly*) the "Exotic Propulsion Initiative. It is possible to donate to the fund at our website. SSI is a 501(c)3 non-profit and thus contributions are tax-deductiable. Targeted contributions go almost 100% to the named projects since we have very modest overhead costs (we don't pay salaries to our volunteer staff, for example).
unless HMXHMX cares to post further answers, it is advisable that anybody having further questions on SSI donations directly addresses them to the Contact listed at www.ssi.org
Space Studies Institute
16922 Airport Blvd.
#24
Mojave, CA 93501
PHONE (661) 750-2774
EMAIL [email protected]
and further inquires about destination of funds for targeted tax-deductible contributions, particularly if they have an interest in targeting a specific effort with their funds.
I am somewhat curious as to why AM modulation would increase the drives output. Is it possible that the modulation scheme is increasing the average power output, or is something else in play.
I'm wondering what it would do with pulsed RF at a high rep rate?
That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact. What we know in this regard is that the experimenters in the UK and China claim to have measured greater thrust force using a magnetron (for whatever reason) and that a magnetron performs amplitude, frequency and phase modulation of the carrier wave. We should exercise caution as neither the UK, nor the Chinese teams have been as forthcoming with data as NASA Eagleworks. Those experiments (using a magnetron) remain to be replicated at NASA Eagleworks.
Concerning what a pulsed RF at a high rep rate would do, I expect that is something that Dr. White should be able to input in his code and give you an answer, but again whether such an answer from his computer code would be correct remains to be confirmed.
My understanding is that NASA Eagleworks is planning to replicate this June the experiments in the UK and China using a magnetron.
So other than what is described in the links below, is there any proof that plane waves can travel slower or faster than c in vacuum?
http://www.sciencemag.org/content/347/6224/857
http://arxiv.org/abs/1411.3987
http://en.m.wikipedia.org/wiki/Scharnhorst_effect
Still very much not proven.
I've been following this since New Scientist got in hot water for publishing an article on Shawyer's work back in 2006. It's exciting to see it has not been yet falsified. The debate and contributions in this thread remind me of the SpaceX video fixing effort; NSF is transcending the traditional role of forums and becoming some kind of collaborative knowledge creation nexus.
Preamble over, I have a suggestion (and hopefully this makes it clear why this comment is here rather than in the article thread): There are lots of new posters who are bringing up problems which have already been addressed up thread. One of the problems of the linear thread style discussion is that it makes it difficult for people to see what has been done. The new article is a wonderful overview of the work, but I wonder if there's room for a page/article/site which lists possible sources of error/standard criticisms of the physical impossibility (maybe each as a linkable heading), and describes clearly what has been done to eliminate them from the system or accurately measure errors, and to theoretically address apparent contradictions to physical laws. I have in mind something like Grist's 'how to talk to a climate sceptic' (http://grist.org/series/skeptics/) where many common talking point issues with AGW are listed, and debunked.
It could be useful if this list were editable like a wiki, so that when someone comes with a complaint already addressed, they can be directed to read that page in general, or linked to the explanation of their issue in particular, but also, if the suggestion is new, it can be easily added as an 'as yet un-eliminated issue' and can await further data.
can anyone explain this point better?
from http://emdrive.com/faq.html
Q. Why does the thrust decrease as the spacecraft velocity along the thrust vector increases?
A. As the spacecraft accelerates along the thrust vector, energy is lost by the engine and gained as additional kinetic energy by the spacecraft. This energy can be defined as the thrust multiplied by the distance through which the thrust acts. For a given acceleration period, the higher the mean velocity, the longer the distance travelled, hence the higher the energy lost by the engine.
This loss of stored energy from the resonant cavity leads to a reduction in Q and hence a reduction of thrust.
The key question is why can't you just turn the machine off and start again from a new reference frame, giving you a traditional interpretation of a propellentless drive and free energy.
can anyone explain this point better?
from http://emdrive.com/faq.html
Q. Why does the thrust decrease as the spacecraft velocity along the thrust vector increases?
A. As the spacecraft accelerates along the thrust vector, energy is lost by the engine and gained as additional kinetic energy by the spacecraft. This energy can be defined as the thrust multiplied by the distance through which the thrust acts. For a given acceleration period, the higher the mean velocity, the longer the distance travelled, hence the higher the energy lost by the engine.
This loss of stored energy from the resonant cavity leads to a reduction in Q and hence a reduction of thrust.
The key question is why can't you just turn the machine off and start again from a new reference frame, giving you a traditional interpretation of a propellentless drive and free energy.
Reading that Q/A, ascribing a 'book-keeping' ability to such a device in regards to reference frames sounds unphysical to me. I can't do anything with that. I tend to believe that Mr. Shawyer might have accidentally found something mind-blowing.. but his explanations just don't add up. It might work for, uh, different reasons than he assumes.
;)
can anyone explain this point better?
from http://emdrive.com/faq.html
Q. Why does the thrust decrease as the spacecraft velocity along the thrust vector increases?
A. As the spacecraft accelerates along the thrust vector, energy is lost by the engine and gained as additional kinetic energy by the spacecraft. This energy can be defined as the thrust multiplied by the distance through which the thrust acts. For a given acceleration period, the higher the mean velocity, the longer the distance travelled, hence the higher the energy lost by the engine.
This loss of stored energy from the resonant cavity leads to a reduction in Q and hence a reduction of thrust.
The key question is why can't you just turn the machine off and start again from a new reference frame, giving you a traditional interpretation of a propellentless drive and free energy.
Contra the usual popularisations, Special Relativity doesn't remove the possibility of a preferred reference frame for the Universe, it just makes it very hard to observe. An alternative, being explored, is Lorentzian relativity, which experimentally gives much the same results as SR, but an absolute frame is preserved. This makes 'accounting' for one object's energy relative to another quite straightforward. These thrusters might provide one means of experimentally determining which version of Relativity is correct.That is one branch of that tree I mentioned: it works wrt to some specific frame of reference. In this case it is probably not at rest when turned on and would have a tendency to rush off in one direction, and generate power rather than expend it. For example apparently there is something called the comoving cosmic rest frame that earth is moving at about 400km/s relative to. http://en.wikipedia.org/wiki/Cosmic_microwave_background#Features
I'm aware that my technical skills are most likely inferior to most of the ppl working at Eagleworks, so I've been pondering if it would be wise to bring up the following issue, but ah, why not...
About the high powered Shawyer-like rotating demonstrator that Eagleworks is building to be ready by june:
One of the main criticism about the non-vacuum demonstrator that Shawyer build, to showoff one of his early EMdrive workings, was that - according to critics - some kind of hot air jet was leaking from non-welded micro openings at the large base of the frustum.
I understand that Eagleworks will also not operate their version in vacuum, as its purpose is to illustrate an effective motion generated by the EM drive. Consequently they will most likely encounter the same remarks...
Countering that "hot air jet" criticism is fairly easy : just build an open enclosure that, in case of a leakage jet , would generate an opposing reaction force to the direction the frustum is supposed to go.
IF the setup turns clockwise, then some sort of hot jet is indeed in play,
however...
if it rotates counterclockwise then clearly, the EMdrive is for real...
In all honesty, a simple well taped cardboard enclosure would be enough, just to redirect the supposedly reactionary "exhaust" forces... Of course , testing with and without enclosure is a must, for reference.
This upcoming test in June will be a real "make or brake" event. No more endless discussions about measurement procedures and potential measurement errors.
I'm sooo in anticipation modus now.. All it needs to do is...TURN in the right direction. :-X
I am somewhat curious as to why AM modulation would increase the drives output. Is it possible that the modulation scheme is increasing the average power output, or is something else in play.
I'm wondering what it would do with pulsed RF at a high rep rate?
That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact. What we know in this regard is that the experimenters in the UK and China claim to have measured greater thrust force using a magnetron (for whatever reason) and that a magnetron performs amplitude, frequency and phase modulation of the carrier wave. We should exercise caution as neither the UK, nor the Chinese teams have been as forthcoming with data as NASA Eagleworks. Those experiments (using a magnetron) remain to be replicated at NASA Eagleworks.
Concerning what a pulsed RF at a high rep rate would do, I expect that is something that Dr. White should be able to input in his code and give you an answer, but again whether such an answer from his computer code would be correct remains to be confirmed.
My understanding is that NASA Eagleworks is planning to replicate this June the experiments in the UK and China using a magnetron.
Dr. Rodal:
"That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact."
I think I may have verified today the need for large time rate of change of the resonant circuit phase changes as the RF amplifier driven 1,937.088 MHz, +/- ~25kHz sine wave oscillates back and forth through the resonance frequency of the frustum cavity. Through a methodical tuning campaign using our triple stub Z-matching tuner and 2 feet of RG-8 coax as the main transmission line to the frustum, I marched the Smith Chart solution circle around its impedance space while checking the thrust output for each over a dozen stub tuner configurations. Only those tuning solutions that maximized the phase change through resonance over the smallest frequency span generated the largest thrust signatures and in fact it overcame its lower Q-factors that those solutions provided. In fact a running solution that yielded Q-factor solutions as high as 7,500 were out performed by two or even three to one in thrust output by tuning solutions that had half these peak Q-factors, but maximized the resonant phase change per kHz. And yes, the input power was maintained at around 50W for all tests. More data later this week as I continue this investigation.
BTW, our Eagleworks Dynamics of the Quantum Vacuum paper has finally been published on the NASA/NTRS server. You can find it here:
http://tinyurl.com/mw64rsn
Best, Paul M.
Folks:
In the meantime, lets ask why 60 watts of relatively harmonic free sine-wave RF power at the 1,937.118 MHz AKA the TM212 resonant frequency in this copper frustum cavity, can only generate a paltry ~60uN, whereas the Chinese claimed to have produce 160,000uN using just ~150 watts of 2,450 MHz RF signals from a magnetron? The magnetron RF signal source that is anything but a pure sine-wave generator, that instead has a modulated FM bandwidth of at least +/-30 MHz that is also concurrently amplitude modulated (AM) with thermal electron noise.
Taking a critical look at this question, and knowing that the spectral shape of a magnetron looks like (see below) compared to a CW spike. It seems evident that a CW spike isn't the best waveform to use if you want to maximize thrust. Dollars to donuts says the Chinese are making full use of the available bandwidth of their resonant cavity by using that noisy magnetron. Magnetrons have lots of phase noise too. You can't easily use them on phased array radars because of that for example.
Now to put this idea to test, Q: What is the bandwidth of the resonant cavity and what is the 90 percent power bandwidth of the signal you are driving it with? What kind of sig gen are you using? Can it do FM? Can you do any advanced waveforms like a PSK waveform? Do you have a way to produce wideband noise or a spread spectrum carrier for your testing? Can you do any waveforms like at the bottom?
Also during researching other possible theories which could explain Emdrive we found ample literature stating that molecules acquire a kinetic momentum during the switching of the magnetic field as a result of its interaction with the vacuum field. If correct, that may well be a very significant lead. So that raises the question, how does one increase the switching rate? What about phase shifting? http://en.wikipedia.org/wiki/Phase-shift_keying
Phase shifting seems important.
https://www.viasat.com/files/assets/web/datasheets/EBEM_MD-1366_043_web.pdf
One of these driving your amp would be helpful. They go up to 2ghz.
http://en.m.wikipedia.org/wiki/Scharnhorst_effect
Still very much not proven.
I don't think this proves it but it looks experimental.
http://cds.cern.ch/record/370620 from (https://scholar.google.com/scholar?cluster=1710259071594791986&hl=en&as_sdt=0,48)
Making the vacuum devoid of energy, (wavelengths restricted from existing between the 2 plates) I would assume might change the vacuum dielectric constant to lower than one. Having an abundance of energy, giving a dielectric greater than one. Maybe similar to how light might slow down near large gravitational objects, though when measured inside the field it still appears, because of shrunken rulers, that light velocity is still the same.
Another paper starting on page 14 that suggest super-luminal tunneling (http://arxiv.org/pdf/1008.1640v2.pdf).
This one seems to deal with it specifically (http://arxiv.org/abs/0901.0508).
one dealing with single photons (http://arxiv.org/abs/0708.3889)
appears connected (http://www.emis.ams.org/journals/SIGMA/2014/005/sigma14-005.pdf) (discusses moving faster than light)
Thanks for pointing out where the idea came from for the super luminal propagation between plates. Hmm, I suppose from the link you gave it suggests the effect is not measurable (change in velocity) which contrasts with the experimental claim of having measured super-luminal velocity. Interesting.
Not to this level of precision and not without knowing material properties.Well, one shouldn't even see a drift the size of the measured force, when it's not even sub-micronewton range.Heat transfer, thermal expansion, thermal stress analysis for uncoupled and for coupled problems, in static and dynamic problems of complicated geometry and materials can be analyzed and modeled with Finite Element analysis (NASTRAN, ANSYS, ABAQUS, ADINA, COMSOL, etc.), just like rockets, spacecrafts and military and commercial aircraft have been analyzed for decades.
If one is heating metal, one is probably heating it unevenly, and it bends as long as heat is applied (the hotter material expands more), with a fairly short time constant (because the temperatures will equalize quickly once the heat source is off). Then the heat gets slowly conducted to another structural element, and that structural element happens to bend in a way that influences the experiment in the other direction.
How much each structural element will bend will depend to how tight the screws are tightened, what stresses are already in the metal, and so on and so forth; it's essentially impossible to account for.
Here is an exact solution of the thermal buckling problem for the EM Drive's truncated cone base:Now if he also made the vacuum chamber in his wife's dining room, and took apart his microwave oven for the RF source, and been testing everything in his basement, there wouldn't be a problem here.
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
The issue for analyzing thermal structural effects (and other effects) for the EM Drive project at NASA Eagleworks is not a matter of present ability to be analyzed but is, instead, a matter of scarcity of project resources (money, time, and personnel) to analyze them. For example, NASA's EM Drive truncated cone was made by Paul March himself in Paul March's wife dining room. NO TAXPAYER's tax $$$ involved in its construction.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327937#msg1327937Sorry, I would trust a shielding box much more than I would trust your calculations (when you are apparently unable to even get rid of the "thermal drift"). The pendulum arms are mechanically complex and made of materials that were never characterized with a necessary degree of precision. The cavity is made in a dining room, as you say. edit: and the springs that the pendulum is suspended on are getting heated up, no? Possibly by an electric current? Seriously?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635221;image)
Engineers and scientists interested in this project, (like @frobnicat, @notsosureofit, @aero, myself, etc.) have contributed their time as well to model different aspects of this experiment to try to distinguish any artifacts from real effects. Earlier on I contributed results of a fully-coupled nonlinear analysis of the torque pendulum used in the experiment, as well as Autocorrelation, and Power Spectral Density analysis of the data.
Concerning the issue of shielding, @aero has contributed a MEEP analysis of evanescent waves leaking from the EM Drive, and possibly interacting with the stainless steeel vacuum chamber. Subsequently, Paul March conducted an experiment with the EM Drive outside the stainless steel chamber that may have nullified that explanation.
@Mulletron has contributed his own resources and time to run his own EM Drive experiment from a hanging torsional pendulum.
Paul March has contributed detailed information about the experimental set-up, and if you are interested, you can also contribute any engineering, preferably quantitative, theoretical, numerical or experimental analysis you may be able to contribute.
Lastly, the Eagleworks Lab's next paper on the Q-V entitled "Dynamics of the Vacuum" will be out on the NASA NTRS internet servers just any day now....
you are apparently unable to even get rid of the "thermal drift"
Lastly, the Eagleworks Lab's next paper on the Q-V entitled "Dynamics of the Vacuum" will be out on the NASA NTRS internet servers just any day now....
Sorry if I missed it, but did this paper get released? If so, where?
Lastly, the Eagleworks Lab's next paper on the Q-V entitled "Dynamics of the Vacuum" will be out on the NASA NTRS internet servers just any day now....
Sorry if I missed it, but did this paper get released? If so, where?
I am somewhat curious as to why AM modulation would increase the drives output. Is it possible that the modulation scheme is increasing the average power output, or is something else in play.
I'm wondering what it would do with pulsed RF at a high rep rate?
That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact. What we know in this regard is that the experimenters in the UK and China claim to have measured greater thrust force using a magnetron (for whatever reason) and that a magnetron performs amplitude, frequency and phase modulation of the carrier wave. We should exercise caution as neither the UK, nor the Chinese teams have been as forthcoming with data as NASA Eagleworks. Those experiments (using a magnetron) remain to be replicated at NASA Eagleworks.
Concerning what a pulsed RF at a high rep rate would do, I expect that is something that Dr. White should be able to input in his code and give you an answer, but again whether such an answer from his computer code would be correct remains to be confirmed.
My understanding is that NASA Eagleworks is planning to replicate this June the experiments in the UK and China using a magnetron.
Dr. Rodal:
"That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact."
I think I may have verified today the need for large time rate of change of the resonant circuit phase changes as the RF amplifier driven 1,937.088 MHz, +/- ~25kHz sine wave oscillates back and forth through the resonance frequency of the frustum cavity. Through a methodical tuning campaign using our triple stub Z-matching tuner and 2 feet of RG-8 coax as the main transmission line to the frustum, I marched the Smith Chart solution circle around its impedance space while checking the thrust output for each over a dozen stub tuner configurations. Only those tuning solutions that maximized the phase change through resonance over the smallest frequency span generated the largest thrust signatures and in fact it overcame its lower Q-factors that those solutions provided. In fact a running solution that yielded Q-factor solutions as high as 7,500 were out performed by two or even three to one in thrust output by tuning solutions that had half these peak Q-factors, but maximized the resonant phase change per kHz. And yes, the input power was maintained at around 50W for all tests. More data later this week as I continue this investigation.
BTW, our Eagleworks Dynamics of the Quantum Vacuum paper has finally been published on the NASA/NTRS server. You can find it here:
http://tinyurl.com/mw64rsn
Best, Paul M.
I know Mulletron. What I want to know is exactly how Dr White theory deals with superluminal speeds, which most physicists say leads to time-travel to the past and all the paradoxes that surface from that.
According to the video I showed from Dr Davis, superluminal speeds WITHOUT time-travel to the past are possible, if the light cone is tilted from 0 to 90 degrees only...
I think this question is related to spaceflight applications exactly because time travel IS an issue at relativistic velocities (to the future) and superluminal velocities (to the past, but not according to Dr Davis)
This question is probably more related to the spaceflight applications of a warp drive than the pure theoretical issues of how EM and Warp Drives work on quantum level, since the first is a result of spaceflight application while the second (which is being discussed in this thread) is not.
Don't forget that the ship is not really moving at relativistic speeds: space is. Consequently, you could take a trip to Alpha Centauri in 2 days (or less with more power... who knows?), turn your ship around and observe the Earth as it was four years ago (as light has taken four years to get there - slow coach!). You could then observe Alpha Centauri as it is "now", and how people on the Earth will see it in four years.
With this type of technology, it would be possible to predict when locally past events are going to be observable from the point of view of the Earth (or any other point that the light from such events had not yet reached). For example, a ship 1 light-day out from the Earth in the right place could witness a supernova before the Earth does and then be able to return to the Earth almost instantly and tell astronomers about the incoming light wave so that they could prepare to observe it.
Proviso: I am not an expert in time travel and I also have doubts about Dr Who.
And what about the experimental observation of non-reciprocity in room temperature and pressure nitrogen (largest portion of air) that was reported? That is also unbalanced momentum.From my recollection of reading your prior links, those involved nonlinear polarization, hence not addressed by linear, isotropic Maxwell's equations. One of the papers addressed a 2nd order term and another addressed a 4th order term in a nonlinear perturbation analysis.
And what about the experimental observation of non-reciprocity in room temperature and pressure nitrogen (largest portion of air) that was reported? That is also unbalanced momentum.From my recollection of reading your prior links, those involved nonlinear polarization, hence not addressed by linear, isotropic Maxwell's equations. One of the papers addressed a 2nd order term and another addressed a 4th order term in a nonlinear perturbation analysis.
Clearly, a nonlinear differential equation does not have a simple harmonic solution.
And what about the experimental observation of non-reciprocity in room temperature and pressure nitrogen (largest portion of air) that was reported? That is also unbalanced momentum.From my recollection of reading your prior links, those involved nonlinear polarization, hence not addressed by linear, isotropic Maxwell's equations. One of the papers addressed a 2nd order term and another addressed a 4th order term in a nonlinear perturbation analysis.
Clearly, a nonlinear differential equation does not have a simple harmonic solution.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1361903#msg1361903
bilinear magneto-electric effects correspond to a coupling beyond the electric dipole approximation.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
It'd be great also if there was a list of graphs organized by resonance mode (rather than an entirely data-free article). What I see so far is that in vacuum all responses are slower...It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
What are you talking about? Maxwell's equations apply to EM radiation unequivocally. Especially in these low power regimes there is no chance of observing any perturbations due to higher order effects from field theory.
Look, I want to believe in a "reactionless" drive as much as the next SF junkie, but this does not pass the smell test. Consider:
e
0. The proposed explanations violate: conservation of energy, conservation of momentum, and the Lorentz transformations. These are some of the best-tested physical arguments we have today, and yet this "drive" violates them by huge orders of magnitude. Is it really plausible that 100+ years of experiments have failed to notice a comparatively huge effect? RF cavities are not a poorly understood system. I used to work with superconducting RF cavities for particle accelerators with Q > 1 million supporting fields of > 10 MV/m. I can guarantee you we would have noticed if power was disappearing into "thrust", or if the damn things were starting to levitate.
1. Even if we are pushing against the "quantum vacuum" this does not make sense, as any such vacuumo must be charge neutral and so we would be pushing in opposite directions on electrons and positrons. Not to mention the accelerated positrons would smash into the surrounding cavity, producing copious, easily-observable gamma rays.
1a. Even ignoring this objection, to promote particles from "virtual" to real (as in Hawking radiation...) you have to provide the particles with their mass-energy. 511 keV per electron/positron. Does this make sense?
Assume 100% of the energy delivered to the cavity goes into making virtual particles real: 100 W / (mass of electron * c^2) = 1e15 electrons / s. Assume the particles are instantaneously acclerated to the speed of light (a pretty generous assumption). Then F = (1e15 electron/s)*(mass of electron)*(speed of light) = 2e-7 newtons. Much smaller than what we observe. The explanation does not hold up to scrutiny.
2. The "quantum vacuum"/Casimir effect should not be given more emphasis than is appropriate. It is a calculational tool. For example, one can explain the casimir effect solely through the van der Waals forces between two neighboring conductors, without handwaving explanations about virtual particles: http://physics.stackexchange.com/questions/11544/vander-waals-and-casimir-forces
3. The quantum vacuum publication referenced earlier is really, really bad. It starts with the Bohr formula for hydrogen (thus neglecting any fine structure, etc... effects), and takes a "radius" (which as we know from QM should not be interpreted literally...) to get a volume and from that some kind of density. This has no physical meaning. Then a function 1/r^4 is fitted to the values -- with no justification! This is then compared to the casimir force for cavities separated by this radius... and the values are pretty far off. But it looks like a factor of 1/3! So some further handwaving about general relativity which also has a factor of 1/3 in one equation! Then there's a whole word salad about solving hydrogen atom wavefunctions with COMSOL [???], which is ridiculous since any undergraduate physics students can solve them with pen and paper...
This papers seems explicitly designed to use lots of fancy terminology and equations to look impressive to anyone with no background in physics, while saying nothing at all of substance. It does not even rise to the level of coherence.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
What are you talking about? Maxwell's equations apply to EM radiation unequivocally. Especially in these low power regimes there is no chance of observing any perturbations due to higher order effects from field theory.
Look, I want to believe in a "reactionless" drive as much as the next SF junkie, but this does not pass the smell test. Consider:
e
0. The proposed explanations violate: conservation of energy, conservation of momentum, and the Lorentz transformations. These are some of the best-tested physical arguments we have today, and yet this "drive" violates them by huge orders of magnitude. Is it really plausible that 100+ years of experiments have failed to notice a comparatively huge effect? RF cavities are not a poorly understood system. I used to work with superconducting RF cavities for particle accelerators with Q > 1 million supporting fields of > 10 MV/m. I can guarantee you we would have noticed if power was disappearing into "thrust", or if the damn things were starting to levitate.
1. Even if we are pushing against the "quantum vacuum" this does not make sense, as any such vacuumo must be charge neutral and so we would be pushing in opposite directions on electrons and positrons. Not to mention the accelerated positrons would smash into the surrounding cavity, producing copious, easily-observable gamma rays.
1a. Even ignoring this objection, to promote particles from "virtual" to real (as in Hawking radiation...) you have to provide the particles with their mass-energy. 511 keV per electron/positron. Does this make sense?
Assume 100% of the energy delivered to the cavity goes into making virtual particles real: 100 W / (mass of electron * c^2) = 1e15 electrons / s. Assume the particles are instantaneously acclerated to the speed of light (a pretty generous assumption). Then F = (1e15 electron/s)*(mass of electron)*(speed of light) = 2e-7 newtons. Much smaller than what we observe. The explanation does not hold up to scrutiny.
2. The "quantum vacuum"/Casimir effect should not be given more emphasis than is appropriate. It is a calculational tool. For example, one can explain the casimir effect solely through the van der Waals forces between two neighboring conductors, without handwaving explanations about virtual particles: http://physics.stackexchange.com/questions/11544/vander-waals-and-casimir-forces
3. The quantum vacuum publication referenced earlier is really, really bad. It starts with the Bohr formula for hydrogen (thus neglecting any fine structure, etc... effects), and takes a "radius" (which as we know from QM should not be interpreted literally...) to get a volume and from that some kind of density. This has no physical meaning. Then a function 1/r^4 is fitted to the values -- with no justification! This is then compared to the casimir force for cavities separated by this radius... and the values are pretty far off. But it looks like a factor of 1/3! So some further handwaving about general relativity which also has a factor of 1/3 in one equation! Then there's a whole word salad about solving hydrogen atom wavefunctions with COMSOL [???], which is ridiculous since any undergraduate physics students can solve them with pen and paper...
This papers seems explicitly designed to use lots of fancy terminology and equations to look impressive to anyone with no background in physics, while saying nothing at all of substance. It does not even rise to the level of coherence.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
I'm going to wallop you in the morning. :D Hope you know what you're attacking me for (what I've been advocating which isn't QVPT BTW) You might want to make sure you have your facts straight. This is your head start.
This is not science, it is cargo cult science.
I still don't understand why major laboratories can't be enlisted to verify or disprove the phenomenon.Because it is obvious pseudoscience and is treated as such (unlike e.g. early cold fusion, which didn't look anywhere near as silly and resulted in many replication attempts worldwide).
I still don't understand why major laboratories can't be enlisted to verify or disprove the phenomenon.Because it is obvious pseudoscience and is treated as such (unlike e.g. early cold fusion, which didn't look anywhere near as silly and resulted in many replication attempts worldwide).
I still don't understand why major laboratories can't be enlisted to verify or disprove the phenomenon.Because it is obvious pseudoscience and is treated as such (unlike e.g. early cold fusion, which didn't look anywhere near as silly and resulted in many replication attempts worldwide).
I still don't understand why major laboratories can't be enlisted to verify or disprove the phenomenon.Because it is obvious pseudoscience and is treated as such (unlike e.g. early cold fusion, which didn't look anywhere near as silly and resulted in many replication attempts worldwide).
Naked disdain on the grounds of established theory, without citation of related experiments or numerical analysis, is unhelpful and unproductive.
I still don't understand why major laboratories can't be enlisted to verify or disprove the phenomenon.Because it is obvious pseudoscience and is treated as such (unlike e.g. early cold fusion, which didn't look anywhere near as silly and resulted in many replication attempts worldwide).
Pseudoscience in what sense?
Is it based on falsifiable assertions or not? As far as I know, yes. Either it provides thrust or it doesn't. "Eppur si muove" at its best.
Can it be replicated? Sure, there's nothing magical with the setup. Any willing and able engineer could make one (and several around here are).
Does it work? We don't know for certain yet. There are hints of the answer being yes, but more replications are in order.
Should we ban and discourage any experiments on this obviously silly idea, only because it goes against our models and theories? Definitely not.
So, an opinion here - I think this thread should be kept as the place where all the theorycrafting and experimental work is specifically discussed by (by and large) the people involved. The strong skepticism and debate over the practicality/realism of the technology and etc ought to be taken perhaps to the article thread, to keep this one cleaner and more usable/readable.It would be a very good idea for the moderators to set up some sort of rules like that.
If you have a new physical theory which predicts some phenomenon, it should reduce to previously known physical theories, and be able to explain existing experiments and observations. If I believe that the EM drive is actually providing some nonclassical, unexplained thrust, I must throw out 100+ years of physics experiment and theory. I choose not to do that, which is why I do not believe further experimentation is warranted. Others may choose differently, but then they should ask themselves why they are so eager to disregard such a large body of established science.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
If you have a new physical theory which predicts some phenomenon, it should reduce to previously known physical theories, and be able to explain existing experiments and observations. If I believe that the EM drive is actually providing some nonclassical, unexplained thrust, I must throw out 100+ years of physics experiment and theory. I choose not to do that, which is why I do not believe further experimentation is warranted. Others may choose differently, but then they should ask themselves why they are so eager to disregard such a large body of established science.
Forget all these new theories for the moment. Concentrate on the experiment.
If all there is to these experiments is experimental error, then we can forget the whole thing.
If there is anomalous thrust from these experiments, then theorists can try to figure out how it works.
Some very intelligent and highly trained people here have been trying to show these results are experimental error. They are still talking about it because they can't explain away the results yet.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
Calling it cargo cult science is a bit too harsh. I reserve that description for individuals who have Bizarro World concepts of science, physics, etc. This is not the case here. What is missing are controlled experiments that would validate any conventional explanations for the anomalous thrust. These researchers are over-reaching. They are too eager to show just positive results. I am 99% certain there is nothing here. To explain the 1%: There remains a possibility that Shawyer has discovered something and the Eagleworks team are just not able to replicate what he has done. To their credit the Eagleworks team have provided a lot of experimental results in the last year. Shawyer has not done this. What I have seen in both the Eaglework's thrust graphs and the few of Shawyer's that I have seen is a lack of consistency in the step response of these devices. The calibration force (a capacitor on the Eagleworks setup) produces a driving function that can be considered to be two step functions. Anything else that drives this torque pendulum with a step function should cause the same system response. That is fundamental physics any mechanical or electrical engineer would agree with. But we don't see this happening when the RF is switched on. We also see an effect that looks like there is stored momentum. How is this happening? There is something else causing the "anomalous thrust". Until the effects of that other cause are nulled out any actual warp-drive or em-drive thrust has not been observed because a priori it must have the same system response as the calibration drive.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
Calling it cargo cult science is a bit too harsh. I reserve that description for individuals who have Bizarro World concepts of science, physics, etc. This is not the case here. What is missing are controlled experiments that would validate any conventional explanations for the anomalous thrust. These researchers are over-reaching. They are too eager to show just positive results. I am 99% certain there is nothing here. To explain the 1%: There remains a possibility that Shawyer has discovered something and the Eagleworks team are just not able to replicate what he has done. To their credit the Eagleworks team have provided a lot of experimental results in the last year. Shawyer has not done this. What I have seen in both the Eaglework's thrust graphs and the few of Shawyer's that I have seen is a lack of consistency in the step response of these devices. The calibration force (a capacitor on the Eagleworks setup) produces a driving function that can be considered to be two step functions. Anything else that drives this torque pendulum with a step function should cause the same system response. That is fundamental physics any mechanical or electrical engineer would agree with. But we don't see this happening when the RF is switched on. We also see an effect that looks like there is stored momentum. How is this happening? There is something else causing the "anomalous thrust". Until the effects of that other cause are nulled out any actual warp-drive or em-drive thrust has not been observed because a priori it must have the same system response as the calibration drive.
Well then let's hear your suggestions for how these concerns can be dealt with then? After all that's what this thread is all about.:)
Why don't we see any interaction in these vastly larger fields, or any "spacetime bending"?. Assuming that the EM Drive thrust is eventually confirmed could it be that this same effect is responsible for Dark Energy and the expanding universe?
Well then let's hear your suggestions for how these concerns can be dealt with then? After all that's what this thread is all about.:)
Well then let's hear your suggestions for how these concerns can be dealt with then? After all that's what this thread is all about.:)
A lot of the skepticism of the results thus far has been centered around the support setups of the drive. Seems like a lot of time and energy could be saved if someone could convince Mr. Musk to tote one up into orbit and turn it on.
A lot of the skepticism of the results thus far has been centered around the support setups of the drive. Seems like a lot of time and energy could be saved if someone could convince Mr. Musk to tote one up into orbit and turn it on.
I suspect that that all be one of the next experiments. I also suspect that performance may be far better than expected the further it is from Earth.
The "Edison Effect" predates the discovery of the electron by 15 years. Manipulating something that you didn't know existed or wasn't fully understood would appear to be doable.
Does Eagleworks have a motto? If not may I suggest something Robert Heinlein once wrote:
"Always listen to experts. They'll tell you what can't be done, and why. Then do it."
It doesn't have anything to do with quantum mechanics, it has to do with relativity. So refutations based on quantum mechanics are irrelevant.
Read the paper. The paper shows that there will be a force. Yes, the content of the paper is hard to keep in your head, but it's in there.
http://www.emdrive.com/theorypaper9-4.pdf
As I understand it, the speed of light, being constant no matter what, essentially creates a separate reference frame from what is going on inside the cavity. The propulsive force is generated because of differences between the two reference frames. Going out on a metaphoric limb, it's like the EM waves in the cavity get squeezed against the speed of light, and it doesn't budge, so the cavity has to.
But it doesn't matter how it is put into words. The reality is not in the narrative metaphors. The reality is in the physics equations, the math. The paper uses well-established equations from physics, and provides sources.
Furthermore, I think there has been some confusion from where I am coming from. I am merely trying to point out that new experiments must be consistent with past experiments when they overlap. No one has addressed my main concern:
Why have we not seen this effect before?
Please try to understand:
IF the EM drive is working
THEN the EM drive must be coupling electromagnetic energy to something
Then why has this coupling never been observed before? This is not a small effect. There are many many test cavities that operate in particle accelerators, as antenna feedhorns, as resonators in oscillators... if this effect were real, it would affect all of these. Why has this not been the case?
We are not working in a realm of physics that is out there... not subatomic particles, not astronomical observations of dark matter/dark energy, not trying to build a fusion device or a quantum computer. This is the kind of physics we need to know 100% to be able to design microwave antennas for cell phone towers.
If you have a new physical theory which predicts some phenomenon, it should reduce to previously known physical theories, and be able to explain existing experiments and observations. If I believe that the EM drive is actually providing some nonclassical, unexplained thrust, I must throw out 100+ years of physics experiment and theory. I choose not to do that, which is why I do not believe further experimentation is warranted. Others may choose differently, but then they should ask themselves why they are so eager to disregard such a large body of established science.
I'm going to preface this by admitting straight off the bat that I don't actually know why it wouldn't have been noticed before. However, the functionality of these EM drives is dependent on resonance, which requires the broadcast energy to be absorbed, or at the very least contained, by the cavity. For the purposes of transmission, resonating cavities are a characteristic of inefficiency and loss to design against, no?
So what are the leading contenders among established physical phenomena which could account for some of the observations/results from the experimental apparatus?
Could these results be due to a mere photon rocket - ie. due to mere photon emissions?
Could they be due to the EM fields interacting with the rest of the apparatus in ways that would throw off the measurements?
Could the results be due to some mechanical effect of electric current passing through wires, etc?
List the possible legitimate effects that could be contributing to these anomalous results, and then figure out ways to modify the rig to eliminate or otherwise correct for them.
The mere fact that this saga has continued for 15 years without a definitive experiment such as suggested by squid leads one to smell a rat! Could it all just be due to poor experimental method?
How to eliminate almost all of these (and for the life of me I can't understand why this hasn't been done, as it's pretty obvious) -- and I should credit Dymytry for the suggestion upthread:
1. Place the ENTIRE apparatus in a thermally shielded, electrically shielded hermetic enclosure. Doesn't need to be a vacuum, doesn't need to be anything fancy. A few hours in a machine shop with some aluminum plate is all you need for this. Mu-metal (to screen magnetic fields) would be best, though, with perhaps some polystyrene insulation on the outside. This would include a battery powered RF amplifier. Doesn't need to be anything fancy -- switch it on with a timer after you seal up, for example.
2. Hang the entire apparatus on a Cavendish-style torsion balance.
IF it moves:
3. Replicate the experiment with a 50 ohm load instead of a cavity.
IF it moves:
4. Replicate the experiment with cavities made of different metal, or filled with dielectric... this should reduce the e-field (lower the Q) and show less thrust.
Then I will be much more convinced that something interesting is going on.
Go back and read the entire thread, you'll find they already did most of what you suggested. Their Rig has been tested and has not been falsified.
There is another explanation that has been around for many decades, it is that variations in the gravitational field are indistinguishable from variations in the refractive index of the vacuum. When you refer to the Lorentz invariance of Maxwell's equations, this does not hold in a vacuum where epsilon0 and mu0 are variables. In General Relativity we refer to the metric components, g^uv. These can and are interpreted as components of a variable refractive index, in the Polarizable Vacuum Model. Primarily refined by Hal Puthoff, a few papers of my own and many others have contributed to it. There are many, many papers on this available.
In this case, the interior energy density is not symmetrical, so the refractive index has a gradient. It was said in a previous post that the speed of light inside is different than it is outside. This is the correct interpretation, however it must include a gradient in the refractive index, as it passes through the structure itself, to cause motion. The gradient in the refractive index "is" a gravitational field. That is what the warp drive requires.
In a separate experiment, they may have shown that the speed of light inside the chamber varies. The amount is varies would only be noticed "IF" you were looking for it. Most resonant systems are "tuned" to eliminate such affects in manufacturing. In such a small cavity, I'm not confident it can be measured.
ote]The mere fact that this saga has continued for 15 years without a definitive experiment such as suggested by squid leads one to smell a rat! Could it all just be due to poor experimental method?
Granted. But perhaps maybe its been dragged on for 15 years because no one would take it seriously. Consider how sad it would be if that were the case. This is certainly the first I've heard of it.
Eagleworks isn't full of crackpots. If they discover it was experimental error then that will be the end of it. Hand waving this away because you do not agree with their observations wont kill it, but the science they're doing now will.
ote]The mere fact that this saga has continued for 15 years without a definitive experiment such as suggested by squid leads one to smell a rat! Could it all just be due to poor experimental method?
Granted. But perhaps maybe its been dragged on for 15 years because no one would take it seriously. Consider how sad it would be if that were the case. This is certainly the first I've heard of it.
Eagleworks isn't full of crackpots. If they discover it was experimental error then that will be the end of it. Hand waving this away because you do not agree with their observations wont kill it, but the science they're doing now will.
Hopefully Eagleworks will resolve it, but they haven't yet resolved to everyone's satisfaction whether or not there IS any thrust, and yet they are forging ahead hypothesizing warp effects related to zero point energy!
Even their test setup is only intended to produce micro-Newton thrust levels, extremely difficult to measure requiring complex test equipment all a potential source of measurement error.
The UK and Chinese tests apparently produced thrusts you almost could feel! So with accurate, well thought out measurements, an unambiguous result could be produced. Then would be the time to determine what is causing it.
It is clear that we are operating under other than usual symmetry conditions and that Maxwell's equations as we were trained to use them do not apply.
What are you talking about? Maxwell's equations apply to EM radiation unequivocally. Especially in these low power regimes there is no chance of observing any perturbations due to higher order effects from field theory.
Look, I want to believe in a "reactionless" drive as much as the next SF junkie, but this does not pass the smell test. Consider:
e
0. The proposed explanations violate: conservation of energy, conservation of momentum, and the Lorentz transformations. These are some of the best-tested physical arguments we have today, and yet this "drive" violates them by huge orders of magnitude. Is it really plausible that 100+ years of experiments have failed to notice a comparatively huge effect? RF cavities are not a poorly understood system. I used to work with superconducting RF cavities for particle accelerators with Q > 1 million supporting fields of > 10 MV/m. I can guarantee you we would have noticed if power was disappearing into "thrust", or if the damn things were starting to levitate.
1. Even if we are pushing against the "quantum vacuum" this does not make sense, as any such vacuumo must be charge neutral and so we would be pushing in opposite directions on electrons and positrons. Not to mention the accelerated positrons would smash into the surrounding cavity, producing copious, easily-observable gamma rays.
1a. Even ignoring this objection, to promote particles from "virtual" to real (as in Hawking radiation...) you have to provide the particles with their mass-energy. 511 keV per electron/positron. Does this make sense?
Assume 100% of the energy delivered to the cavity goes into making virtual particles real: 100 W / (mass of electron * c^2) = 1e15 electrons / s. Assume the particles are instantaneously acclerated to the speed of light (a pretty generous assumption). Then F = (1e15 electron/s)*(mass of electron)*(speed of light) = 2e-7 newtons. Much smaller than what we observe. The explanation does not hold up to scrutiny.
2. The "quantum vacuum"/Casimir effect should not be given more emphasis than is appropriate. It is a calculational tool. For example, one can explain the casimir effect solely through the van der Waals forces between two neighboring conductors, without handwaving explanations about virtual particles: http://physics.stackexchange.com/questions/11544/vander-waals-and-casimir-forces
3. The quantum vacuum publication referenced earlier is really, really bad. It starts with the Bohr formula for hydrogen (thus neglecting any fine structure, etc... effects), and takes a "radius" (which as we know from QM should not be interpreted literally...) to get a volume and from that some kind of density. This has no physical meaning. Then a function 1/r^4 is fitted to the values -- with no justification! This is then compared to the casimir force for cavities separated by this radius... and the values are pretty far off. But it looks like a factor of 1/3! So some further handwaving about general relativity which also has a factor of 1/3 in one equation! Then there's a whole word salad about solving hydrogen atom wavefunctions with COMSOL [???], which is ridiculous since any undergraduate physics students can solve them with pen and paper...
This papers seems explicitly designed to use lots of fancy terminology and equations to look impressive to anyone with no background in physics, while saying nothing at all of substance. It does not even rise to the level of coherence.
In conclusion, this whole affair appears to be the work of someone who has convinced himself his theory is right and is on a fishing expedition for evidence that supports it. The experimental design is poor (camera pictures of LabView windows? unable to find an RF amplifier to deliver more than 100W of power? inability to measure forces that would be measurable in the 1800's?), the past 100+ years of physical experiments contradict the experiments, and there is no coherent underlying theory.
This is not science, it is cargo cult science.
Go back and read the entire thread, you'll find they already did most of what you suggested. Their Rig has been tested and has not been falsified.
There is another explanation that has been around for many decades, it is that variations in the gravitational field are indistinguishable from variations in the refractive index of the vacuum. When you refer to the Lorentz invariance of Maxwell's equations, this does not hold in a vacuum where epsilon0 and mu0 are variables. In General Relativity we refer to the metric components, g^uv. These can and are interpreted as components of a variable refractive index, in the Polarizable Vacuum Model. Primarily refined by Hal Puthoff, a few papers of my own and many others have contributed to it. There are many, many papers on this available.
In this case, the interior energy density is not symmetrical, so the refractive index has a gradient. It was said in a previous post that the speed of light inside is different than it is outside. This is the correct interpretation, however it must include a gradient in the refractive index, as it passes through the structure itself, to cause motion. The gradient in the refractive index "is" a gravitational field. That is what the warp drive requires.
In a separate experiment, they may have shown that the speed of light inside the chamber varies. The amount is varies would only be noticed "IF" you were looking for it. Most resonant systems are "tuned" to eliminate such affects in manufacturing. In such a small cavity, I'm not confident it can be measured.
Most microwave sources include a resonant cavity. Waveguides are resonant structures. Most concerning for the present work are superconducting RF cavities in particle accelerators (see the attached picture). I have personally worked with cavities similar to those in the picture. They are superconducting at 4K being made out of niobium, and typically support >10 MV/m of electric field, with quality factors of several 10's of million. Any loss of energy to an external medium would have been readily apparent, and we would not be able to run the LHC if there was some unknown effect affecting these sorts of cavities. Not to mention... those walls are actually fairly thin! If we believe the EM drive thrust claims... they would have buckled under the strain and torn from their mountings.
I tried asking some of these questions before but they were quickly drowned out by senseless bickering, so I'm going to try asking again.
(0) Supposing that you were able to engineer the required negative energy density around the craft in such a way as to produce an Alcubierre style warp bubble. The spacetime curvature in the CENTER but the edges of the bubble itself would be highly warped, and yet you need to have engineered some structure to hold the negative energy density ring in place. Thus it seems that the warping of spacetime would necessarily destroy any toroidal structure used to hold the negative energy in place, making it impossible to maintain such a bubble. Am I missing something here?
(1) The Eagleworks team reportedly made a simulation to predict thrust levels based on the assumption that the vacuum energy of empty space behaves like a plasma which is mutable as suggested by Dr. White. Then, virtual particles would be able to store and propagate momentum as a wave from one virtual particle to the next until it reached a non-virtual particle to finally absorb the momentum. Thus the EmDrive would leave a "wake" and this is exactly how White described it. However there seems to be a problem with this explanation, because with the EmDrive being a resonant cavity, any such QVP wave would need to be initially generated INSIDE the closed cavity, which means the first matter this virtual particle wave would interact with would be the walls of the cavity itself, which would absorb the opposite momentum and thus cancel out any net thrust. What additional assumptions were made in the simulation to make this not cancel out?
(http://www.nasaspaceflight.com/wp-content/uploads/2015/04/2015-04-19-010503-350x259.jpg)
(2) In "The Alcubierre Warp Drive in Higher Dimensional Spacetime", White and Davis (2006) theorized that, under the Chung-Freese model they predicted any torus of positive energy density would give rise to slight negative energy density in its core due to classical energy in 3+1 dimensions being shifted "off brain" into the unobservable higher dimensions. They proposed an experiment to test this by constructing a charged capacitor ring. However, under the mass-energy equivalence, a rapidly spinning torus made of lead would have orders of magnitude greater positive energy density -- so why were they using capacitors in their experiment?
(3) If it were true that any torus of positive energy density contributes to a "boost" factor inside the torus, then it must be to an incredibly small amount, or else people would have noticed by pure chance that objects inside torus tend to move faster, and nobody has noticed this. However, we have noticed that large heavy toruses require more fuel to propel. Thus it seems that this theory of a positive energy density torus giving rise to a net boost in thrust must be impossible.
(4) In "Experimental Concepts for Generating Negative Energy in the Laboratory" Davis and Puthoff (2006) showed that negative energy density was producible in the lab using high energy lasers and other methods, and this would not require the more radical assumptions of extra dimensions in the Chung-Freese model. Why weren't these methods explored?
(5) On Rodal's writeup he mentioned that skeptics were hesitant to accept the idea of a mutable QVP because "The mainstream physics community assumes the Quantum Vacuum is indestructible and immutable because of the experimental observation that a fundamental particle like an electron (or a positron) has the same properties (e.g. mass, charge or spin), regardless of when or where the particle was created". However, if the QVP was storing momentum then any non-virtual particles exposed to it would merely absorb this momentum, which would restore the QVP to its usual ground state without changing any more fundamental properties. Thus this criticism seems to be moot.
Regarding 1):
Virtual particle pairs only exist for an extremely short time and then vanish again. One question I already asked elsewhere is: If virtual particle pairs gained momentum and they afterwards 'disappeared' again, where would the momentum go?
I haven't been following these threads closely until recently, but I'm really curious if anyone here has examined whether or not Modified inertia from Hubble scale Casimir effects (MiHsC), which is a theory I just came across today, makes any sense at all. I never got far enough in math to really evaluate this level of physics on my own, but the "crackpot" alarms in my head didn't sound as I was reading about it.
The basics of it are, any object moving to the right will create an event horizon somewhere to left beyond which information cannot be observed. Like other event horizons, this will result in radiation (similar to Hawking radiation) called Unruh radiation. The wavelengths for this radiation are at normal accelerations on the order of light years.
But if you have something like a tube with light inside and reflective surfaces, the photons (because of their speed) will generate Unruh wavelength that are the exact resonant frequency of the tube.
In a uniform tube, this does nothing, but in a cone shaped tube, it would bias the direction of force toward the narrow end.
Again, this isn't my theory, it is proposed by a physicist at Plymouth U in the UK, but it seemed... reasonable.
The theory evidently also has the nice benefit of explaining the effects of dark matter and dark energy without any special tuning, and it explains how inertia works in general from what I was reading.
Does any of that make sense or sound plausible?
EDIT: I ask mainly because a device like the EmDrive is one of the only testable predictions that you could make with this theory given the technology we have now.
Adding to @Mulletron's guidelines:
Excellent examples of constructive, skeptical criticism on the test set-up are the numerous posts of @frobnicat and @zen-in. They are objective, logical, analytical, systematic, methodical, and they follow the scientific and engineering method without resorting to abusive language...
Adding to @Mulletron's guidelines:
Excellent examples of constructive, skeptical criticism on the test set-up are the numerous posts of @frobnicat and @zen-in. They are objective, logical, analytical, systematic, methodical, and they follow the scientific and engineering method without resorting to abusive language...
Rodal,
Back on the subject of logical and constructive discussion...would you mind responding to the points and questions I just raised above?
Speaking of virtual particles, have there been any attempts to quantify the radiation spewing out of the apparatus? Something like harmonics of 0.511MeV would be a dead giveaway to solving how this thing works (though I highly doubt it is this simple)...
I am assuming the microwaves path is something like this?
(http://i.imgur.com/nA1U9X6.png)
Where forces F0 through F16 represent the force of a single microwave at different time intervals.
If the directional force happens at F2, and the opposing force happens from F3 to F16, this still obeys Newtons third law. Isn't the opposing force just being damped like a spring over time?
If M1, M2, ... Mn represent different microwaves, and each Mi is following a similar course, wouldn't this suggest that the directional force will remain positive at a constant rate until the device is shut off causing all forces to cancel?
Next, using this new Q-V plasma simulation tool that utilizes the instantaneous E&M fields from COMSOL for one complete RF cycle in 5 degree increments as its input file, we are now seeing why we need the PTFE or HDPE dielectrics in the frustum while using near pure sine wave power levels below ~100W in the ~2.0 GHz frequency range to generate detectable thrust, and why Shawyer and the Chinese didn't while pumping 80W to 2,500W using magnetron RF sources. We think the reasons are two fold.
The first is that Shawyer and the Chinese both used magnetron RF sources for their experiments. An RF source that generates large AM, FM and PM modulation of the carrier wave with typical FM modulation bandwidth on the order of at least +/-20 MHz. (These time rate to change of energy modulations increase the Q-V density in our model.)
The second reason we found running these 3D Q-V plasma simulations for the EMPTY copper frustum, was that increasing the input power tends to focus the Q-V plasma flow from near omnidirectional from the frustum at low powers, to a much more jet like beam at higher powers measured in kW to tens of kW-rf. In fact the simulation for the 100W run predicted only ~50uN for our pure RF system with dielectric, while the 10kW run predicted a thrust level of ~6.0 Newton without a dielectric in the cavity. And at 100kW-rf it was now up to ~1300 Newton, but the input power to thrust production nonlinearity was starting to taper off around 50kW. Of course these Q-V plasma thrust predictions are based on the Q-V not being immutable and non-degradable, a feature we admit is not widely accepted by the mainstream physics community, at least at the moment. :)
Next, using this new Q-V plasma simulation tool that utilizes the instantaneous E&M fields from COMSOL for one complete RF cycle in 5 degree increments as its input file, we are now seeing why we need the PTFE or HDPE dielectrics in the frustum while using near pure sine wave power levels below ~100W in the ~2.0 GHz frequency range to generate detectable thrust, and why Shawyer and the Chinese didn't while pumping 80W to 2,500W using magnetron RF sources. We think the reasons are two fold.
The first is that Shawyer and the Chinese both used magnetron RF sources for their experiments. An RF source that generates large AM, FM and PM modulation of the carrier wave with typical FM modulation bandwidth on the order of at least +/-20 MHz. (These time rate to change of energy modulations increase the Q-V density in our model.)
The second reason we found running these 3D Q-V plasma simulations for the EMPTY copper frustum, was that increasing the input power tends to focus the Q-V plasma flow from near omnidirectional from the frustum at low powers, to a much more jet like beam at higher powers measured in kW to tens of kW-rf. In fact the simulation for the 100W run predicted only ~50uN for our pure RF system with dielectric, while the 10kW run predicted a thrust level of ~6.0 Newton without a dielectric in the cavity. And at 100kW-rf it was now up to ~1300 Newton, but the input power to thrust production nonlinearity was starting to taper off around 50kW. Of course these Q-V plasma thrust predictions are based on the Q-V not being immutable and non-degradable, a feature we admit is not widely accepted by the mainstream physics community, at least at the moment. :)
@Paul (and Dr. Rodal who knows that matter for having written the breaking news on NSF homepage):
Can you please clarify two things about that recent predictive simulation:
1- How (i.e. what is the physical cause) does the dielectric enhance and control (hence is mandatory) that almost omnidirectional flow of virtual particles at low power, into a detectable thrust, as per Dr. White's QVF conjecture?
2- Why the model transforms that omnidirectional cloud of QV particles at low powers, into a "jet like beam" at higher powers? (progressively or in a non-linear way BTW?)
Maybe I missed some important messages in the thread, but since there is more and more reactions to your posts and to the NSF news article in the media and twitter, and since Eagleworks hasn't published anything yet about the EmDrive vacuum tests, the RF resonant warp experiment, and the newest simulations, I think those claims (let's start with the low power dielectric and high power spike modeling of QV flow) deserve more explanation.
(2) In "The Alcubierre Warp Drive in Higher Dimensional Spacetime", White and Davis (2006) theorized that, under the Chung-Freese model they predicted any torus of positive energy density would give rise to slight negative energy density in its core due to classical energy in 3+1 dimensions being shifted "off brain" into the unobservable higher dimensions. They proposed an experiment to test this by constructing a charged capacitor ring. However, under the mass-energy equivalence, a rapidly spinning torus made of lead would have orders of magnitude greater positive energy density -- so why were they using capacitors in their experiment?
Go back and read the entire thread, you'll find they already did most of what you suggested. Their Rig has been tested and has not been falsified.
There is another explanation that has been around for many decades, it is that variations in the gravitational field are indistinguishable from variations in the refractive index of the vacuum. When you refer to the Lorentz invariance of Maxwell's equations, this does not hold in a vacuum where epsilon0 and mu0 are variables. In General Relativity we refer to the metric components, g^uv. These can and are interpreted as components of a variable refractive index, in the Polarizable Vacuum Model. Primarily refined by Hal Puthoff, a few papers of my own and many others have contributed to it. There are many, many papers on this available.
In this case, the interior energy density is not symmetrical, so the refractive index has a gradient. It was said in a previous post that the speed of light inside is different than it is outside. This is the correct interpretation, however it must include a gradient in the refractive index, as it passes through the structure itself, to cause motion. The gradient in the refractive index "is" a gravitational field. That is what the warp drive requires.
In a separate experiment, they may have shown that the speed of light inside the chamber varies. The amount is varies would only be noticed "IF" you were looking for it. Most resonant systems are "tuned" to eliminate such affects in manufacturing. In such a small cavity, I'm not confident it can be measured.
Yes, the simple formula I put up is based on a similar type of assumption. Could you reference your papers ? (publicly or privately)
Thanks
Edit: Many decades is correct, I'm 40 years out of date trying to catch up on any changes.
Speaking of virtual particles, have there been any attempts to quantify the radiation spewing out of the apparatus? Something like harmonics of 0.511MeV would be a dead giveaway to solving how this thing works (though I highly doubt it is this simple)...
Regarding 1):
Virtual particle pairs only exist for an extremely short time and then vanish again. One question I already asked elsewhere is: If virtual particle pairs gained momentum and they afterwards 'disappeared' again, where would the momentum go?
I just answered your question in the post you replied to...let me try explaining it again...under White's theory, if a virtual particle absorbs the momentum, then it must transfer the momentum to a different particle before it disappears. In the vacuum of empty space, that means it propagates from one virtual particle to the next creating a wave, until the wave reaches a non-virtual particle to absorb the momentum.
Also, if you use the wrong solution method or too large of a timestep (or too small, sometimes!) but the equations are right, you can easily have a simulation which does not conserve energy.
Heck, if you've ever written an orbital mechanics simulation using the simple Euler's method, you often end up with your planets flung out to the stars or changing in orbits unless you use a really, really small step size (but then you get into problems with rounding!).
tl;dr: Computer simulations are no way to prove this thing works. It's easy to glitch them (by accident) into screwing up the physics. And, of course, they are no better than their underlying assumptions (and often are worse...).
That's also a problem. If virtual particles do appear, gain momentum then disappear, momentum conservation seems to be violated. If the virtual particles are promoted as real particles as you suggest and don't disappear, they gain momentum and conservation is preserved, but since they don't escape the cavity (which is hermetically closed) all the momentum sums to zero and there is no thrust, i.e. no EmDrive. [EDIT: it's even worse than that since in a pair production, one particle is an antiparticle, see SH answer just below]Regarding 1):
Virtual particle pairs only exist for an extremely short time and then vanish again. One question I already asked elsewhere is: If virtual particle pairs gained momentum and they afterwards 'disappeared' again, where would the momentum go?
I just answered your question in the post you replied to...let me try explaining it again...under White's theory, if a virtual particle absorbs the momentum, then it must transfer the momentum to a different particle before it disappears. In the vacuum of empty space, that means it propagates from one virtual particle to the next creating a wave, until the wave reaches a non-virtual particle to absorb the momentum.
Or maybe they don't disappear again at all? Hawking radiation is one known example where the addition of energy to a virtual particle pair can promote them into real particles; and that concept's been pretty rigorously analyzed. Maybe that's what's happening here: the energy is promoting virtual particles into real particles and the drive is exchanging momentum between the spacecraft and real particle pairs.
Or maybe they don't disappear again at all? Hawking radiation is one known example where the addition of energy to a virtual particle pair can promote them into real particles; and that concept's been pretty rigorously analyzed. Maybe that's what's happening here: the energy is promoting virtual particles into real particles and the drive is exchanging momentum between the spacecraft and real particle pairs.
That's also a problem. If virtual particles do appear, gain momentum then disappear, momentum conservation seems to be violated. If the virtual particles are promoted as real particles as you suggest and don't disappear, they gain momentum and conservation is preserved, but since they don't escape the cavity (which is hermetically closed) all the momentum sums to zero and there is no thrust, i.e. no EmDrive. [EDIT: it's even worse than that since in a pair production, one particle is an antiparticle, see SH answer just below]Regarding 1):
Virtual particle pairs only exist for an extremely short time and then vanish again. One question I already asked elsewhere is: If virtual particle pairs gained momentum and they afterwards 'disappeared' again, where would the momentum go?
I just answered your question in the post you replied to...let me try explaining it again...under White's theory, if a virtual particle absorbs the momentum, then it must transfer the momentum to a different particle before it disappears. In the vacuum of empty space, that means it propagates from one virtual particle to the next creating a wave, until the wave reaches a non-virtual particle to absorb the momentum.
Or maybe they don't disappear again at all? Hawking radiation is one known example where the addition of energy to a virtual particle pair can promote them into real particles; and that concept's been pretty rigorously analyzed. Maybe that's what's happening here: the energy is promoting virtual particles into real particles and the drive is exchanging momentum between the spacecraft and real particle pairs.
Hawking radiation is only present at the event horizon of a black hole because, in order for it to occur, one of the virtual particles in the pair must be sucked into the black hole while the other managed to escape. This essentially prevents the one that escaped from disappearing back into the vacuum, and energy is conserved because the positive energy of the escaped particle is cancelled out by the negative energy of the particle that got sucked into the black hole, which effectively reduces the black hole's externally measurable mass.
Let us not forget:
Kepler’s laws gave us a beautiful and powerfully predictive description of the Solar System: planets orbiting in ellipses with the Sun at its center. Newton’s Universal Theory of Gravity gave us the physics that explained Kepler’s laws but also showed that they weren’t perfect. Centuries later, Einstein’s General Relativity gave us our modern picture of gravity, showing that Newton’s gravity isn’t quite right. Science progresses by overthrowing old theories and showing that they are wrong… only, very often, the term “wrong” is over-simplistic, hiding subtleties in how science really progresses.
First presented in Second Life on June 6, 2008.
There is infinitely more that we do not know, than we know.
DJ
Hawking radiation is only present at the event horizon of a black hole because, in order for it to occur, one of the virtual particles in the pair must be sucked into the black hole while the other managed to escape. This essentially prevents the one that escaped from disappearing back into the vacuum, and energy is conserved because the positive energy of the escaped particle is cancelled out by the negative energy of the particle that got sucked into the black hole, which effectively reduces the black hole's externally measurable mass.
What you've just said assumes that antiparticles have a negative energy, which has not been proven, and it would rather be the opposite as the various papers and experiments on that subject seems to tell us that antimatter has a positive mass. Thus positive energy.
Antimatter (as per Dirac) is C-symmetry. But charge conjugation does not reverse energy. T-symmetry does. Feynman imagined another type of antiparticles, with PT-Symmetry. Those beasts would have a negative energy, and negative mass (if they have one). But they have never been observed.
if momentum is being anomalously generated by a particular configuration of electric and magnetic fields, all fields must create some momentum as Maxwell's equations are linear[/b]
Hello, I have been following Dr. White's publications with interest since he revived the Alcubierre concept in 2003. I have a few comments and questions below.
...
(3) Evidence in support of the QVP being mutable. a) the force measurements of the EM-drive, b) the Casimir effect, c) as explained here (http://nextbigfuture.com/2015/02/more-emdrive-experiment-information.html), apparently Dr. White was able to show that the electron shell radii of all atoms up to atomic number 7 can be predicted based on the asumption that QVP is mutable. I haven't read the details of that and would be curious to read where this is published if anyone knows. d) A generic property of inflationary cosmology (as written about by Hawking, Alan Guth, Hartle, Turok, Pasachoff, Filippenko, Stenger, Vilenkin and others) is that the universe began from a small quantum fluctuation from the ground state, as stated by Vilenkin "small amount of energy was contained in that [initial] curvature, somewhat like the energy stored in a strung bow. This ostensible violation of energy conservation is allowed by the Heisenberg uncertainty principle for sufficiently small time intervals. The bubble then inflated exponentially and the universe grew by many orders of magnitude in a tiny fraction of a second". Thus, it seems that inflationary cosmology is founded on a principle of mutable QVP as well.
...
That's also a problem. If virtual particles do appear, gain momentum then disappear, momentum conservation seems to be violated. If the virtual particles are promoted as real particles as you suggest and don't disappear, they gain momentum and conservation is preserved, but since they don't escape the cavity (which is hermetically closed) all the momentum sums to zero and there is no thrust, i.e. no EmDrive.Regarding 1):
Virtual particle pairs only exist for an extremely short time and then vanish again. One question I already asked elsewhere is: If virtual particle pairs gained momentum and they afterwards 'disappeared' again, where would the momentum go?
I just answered your question in the post you replied to...let me try explaining it again...under White's theory, if a virtual particle absorbs the momentum, then it must transfer the momentum to a different particle before it disappears. In the vacuum of empty space, that means it propagates from one virtual particle to the next creating a wave, until the wave reaches a non-virtual particle to absorb the momentum.
Or maybe they don't disappear again at all? Hawking radiation is one known example where the addition of energy to a virtual particle pair can promote them into real particles; and that concept's been pretty rigorously analyzed. Maybe that's what's happening here: the energy is promoting virtual particles into real particles and the drive is exchanging momentum between the spacecraft and real particle pairs.
Hi Everyone,
I am an RF engineer in the Microwave Instrument Technology Branch at NASA Goddard Space Flight Center. I had seen a few articles here and there about the EM drive and today it caught my eye on IO9.com. While I have only spent the last hour or so reviewing what has been done to eliminated external factors to explain the phenomenon I would like to offer my two-cents. If what I'm suggesting as an explanation has already been eliminated, I apologize.
Have you considered the effects of breakdown, and in particular multipaction and corona generation? Multipaction breakdown events are known phenomenon on the RF radar and communication systems community. Essentially, at high RF powers you see an effect similar to arcing within your components. This arcing can occur between conductors and dielectrics or even between conductors in vacuum. Sharp edges such as welds and fasteners - particularly in a cavity resonator such as this - can cause these events. This result is damage to the interior conductor and particle generation (even in metal-only situations) as material is "burned." In this case, the metal walls and / or contaminants of your cavity would serve as the propellant. Corona / plasma can then develop from this particle release and exacerbate the situation.
Better descriptions can be found here :
http://en.wikipedia.org/wiki/Multipactor_effect
http://www.microwaves101.com/encyclopedias/multipaction
As a real world example, I am the lead engineer for the Radiometer Front End on the recently launched Soil Moisture Active Passive (SMAP) Mission. (http://smap.jpl.nasa.gov/) We had a terrible problem with multipaction in our RF diplexer which was a cavity resonator - similar to your setup. These devices are essentially three-port band-pass filters whose resonant frequencies are set by the physical dimensions of the (mostly) empty cavity. Picture an empty aluminum box about 10'' x 5'' x 5''. We saw damaging breakdown events beginning around 350W at 1.2GHz which is the nominal operating point of our radar. It took several design iterations and many months to totally eliminate various sources of breakdown including sharp edges, gas trapped by resonator pucks, tuning screws, etc. While your cavity and ours arn't exactly the same one could say the situations are quite similar. The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).
In a nutshell, at these power levels I would be surprised if your systems were not multipacting to some degree as designing a cavity that does not have breakdown at these levels takes a good deal of expertise on the nuances of the issue. So as multipaction events are particle generators these could produce the force you are seeing. What order of magnitude force we would see I havn't the foggiest. But if I were an independent reviewer of your technology I would first ask that you prove this cannot be explained by multipaction. Or show that even if multipaction were occuring the magnitude of the forces involved cannot be explained. These events can be observed by monitoring the RF power level passing through, or in your case reflecting, from a system. An ideal setup would be to add an RF coupler between your magnetron and the cavity and observe the return loss into the system as power is slowly ramped up. You will see a reflected power loss as the energy is converted into the events described. A further test would be to have your resonator opened and carefully inspected by an expert as burn marks and other evidence can be detected optically.
Good luck, I can pass you some names off-line if that is of interest. If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys! :) ). As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.
-Joseph Knuble
(Also, I hope I'm wrong!)
The existence of multipaction is dependent on the following four conditions being met:
The mean free path of the electrons should be (much) greater then the spacing between the opposing surfaces, which is normally only the case in good vacuum and without any further obstruction in the way (no other di-electricum).
The average number of electrons released is greater than one which is dependent on the secondary electron yield of the surface, which in turn is dependent on the field strength (RF power) between the surfaces.
The time taken by the electron to travel from the surface from which it was released to the surface it impacts with, is to be an integer multiple of one half of the RF period (resonance).
The availability of free electrons to start of the release of secondary electrons.
(In space, free electrons are released from the surfaces by high energy particles, while during on-ground testing they are provided by a radioactive source (strontium 90) or an electron gun)
Is this right? This looks to me likebad science. How could thrust fall as speed increases? I also looked to "scientific" paper on emdrive page and there is stated that at about 0.7c thrust reverses?
http://emdrive.com/sciencemissions.html (http://emdrive.com/sciencemissions.html)
...
Hi Everyone,My understanding is the current setup is a little over 1.9 GHz @ 50 watts.
I am an RF engineer in the Microwave Instrument Technology Branch at NASA Goddard Space Flight Center. I had seen a few articles here and there about the EM drive and today it caught my eye on IO9.com. While I have only spent the last hour or so reviewing what has been done to eliminated external factors to explain the phenomenon I would like to offer my two-cents. If what I'm suggesting as an explanation has already been eliminated, I apologize.
Have you considered the effects of breakdown, and in particular multipaction and corona generation? Multipaction breakdown events are known phenomenon on the RF radar and communication systems community. Essentially, at high RF powers you see an effect similar to arcing within your components. This arcing can occur between conductors and dielectrics or even between conductors in vacuum. Sharp edges such as welds and fasteners - particularly in a cavity resonator such as this - can cause these events. This result is damage to the interior conductor and particle generation (even in metal-only situations) as material is "burned." In this case, the metal walls and / or contaminants of your cavity would serve as the propellant. Corona / plasma can then develop from this particle release and exacerbate the situation.
Better descriptions can be found here :
http://en.wikipedia.org/wiki/Multipactor_effect
http://www.microwaves101.com/encyclopedias/multipaction
As a real world example, I am the lead engineer for the Radiometer Front End on the recently launched Soil Moisture Active Passive (SMAP) Mission. (http://smap.jpl.nasa.gov/) We had a terrible problem with multipaction in our RF diplexer which was a cavity resonator - similar to your setup. These devices are essentially three-port band-pass filters whose resonant frequencies are set by the physical dimensions of the (mostly) empty cavity. Picture an empty aluminum box about 10'' x 5'' x 5''. We saw damaging breakdown events beginning around 350W at 1.2GHz which is the nominal operating point of our radar. It took several design iterations and many months to totally eliminate various sources of breakdown including sharp edges, gas trapped by resonator pucks, tuning screws, etc. While your cavity and ours arn't exactly the same one could say the situations are quite similar. The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).
In a nutshell, at these power levels I would be surprised if your systems were not multipacting to some degree as designing a cavity that does not have breakdown at these levels takes a good deal of expertise on the nuances of the issue. So as multipaction events are particle generators these could produce the force you are seeing. What order of magnitude force we would see I havn't the foggiest. But if I were an independent reviewer of your technology I would first ask that you prove this cannot be explained by multipaction. Or show that even if multipaction were occuring the magnitude of the forces involved cannot be explained. These events can be observed by monitoring the RF power level passing through, or in your case reflecting, from a system. An ideal setup would be to add an RF coupler between your magnetron and the cavity and observe the return loss into the system as power is slowly ramped up. You will see a reflected power loss as the energy is converted into the events described. A further test would be to have your resonator opened and carefully inspected by an expert as burn marks and other evidence can be detected optically.
Good luck, I can pass you some names off-line if that is of interest. If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys! :) ). As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.
-Joseph Knuble
(Also, I hope I'm wrong!)
Good luck, I can pass you some names off-line if that is of interest. If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys! :) ). As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.
-Joseph Knuble
(Also, I hope I'm wrong!)
Welcome to the thread :) We hope you are here to stay ;)
Please correct me if I'm wrong, but my understanding of this effect is that the multipactor effect occurs "when electrons accelerated by radio-frequency (RF) fields are self-sustained in a vacuum (or near vacuum)"
The counter-argument to this is that most of the EM Drive experiments have been conducted in ambient conditions (not in a vacuum).
Ok guys, so a lot of new people into this thread, but this thread is mainly for the development of the EM Drive. We knew this would happen, so we have a new "Entry Level" thread for opening questions and general questions.
I've moved the last few pages of new members asking questions into that thread, so if you posted here and can't see it, don't worry, it's in this thread.
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Posting this notice as some sites are linking to this thread and not the section or the article, so people are thinking this is the only thread on this.
Remember to use the above link and allow this thread to continue with the Eaglework folk and others updating progress.
Ok guys, so a lot of new people into this thread, but this thread is mainly for the development of the EM Drive. We knew this would happen, so we have a new "Entry Level" thread for opening questions and general questions.
I've moved the last few pages of new members asking questions into that thread, so if you posted here and can't see it, don't worry, it's in this thread.
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Posting this notice as some sites are linking to this thread and not the section or the article, so people are thinking this is the only thread on this.
Remember to use the above link and allow this thread to continue with the Eaglework folk and others updating progress.
I think we need a F.A.Q.
Ok guys, so a lot of new people into this thread, but this thread is mainly for the development of the EM Drive. We knew this would happen, so we have a new "Entry Level" thread for opening questions and general questions.
I've moved the last few pages of new members asking questions into that thread, so if you posted here and can't see it, don't worry, it's in this thread.
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Posting this notice as some sites are linking to this thread and not the section or the article, so people are thinking this is the only thread on this.
Remember to use the above link and allow this thread to continue with the Eaglework folk and others updating progress.
I think we need a F.A.Q.
Yes, if the EM Drive thread would be about well-understood science and/or engineering, an FAQ section would be great.
We all want answers, that's why we are here.
Unfortunately there is substantial amount of disagreement as to the measurements and even more disagreement about the theories.
Who is going to be in charge of answering the questions? Are (maybe innocently incorrect or innocently misleading) answers provided by forum volunteers for an unsettled, controversial, Research project like the EM Drive more useful than not having an FAQ section?
How can a FAQ section for unsettled Research in a forum be objectively handled for scientific/engineering accuracy?
Who will give an authoritative answer in a forum?
How is misinformation going to be prevented?
How is agreement on what is the correct answer to a question going to be reached?
Even assuming that an FAQ with opposing answers (*) to the questions would be helpful, having somebody choose who is " the most hardcore and knowledgeable" would result in a certain amount of arbitrariness, and the main problem is keeping such FAQ updated with correct information, because it often turns out to be the case that " the most knowledgeable" doesn't have the time to update the FAQ section and often doesn't volunteer, and those who readily volunteer are not " the most knowledgeable" :(Ok guys, so a lot of new people into this thread, but this thread is mainly for the development of the EM Drive. We knew this would happen, so we have a new "Entry Level" thread for opening questions and general questions.
I've moved the last few pages of new members asking questions into that thread, so if you posted here and can't see it, don't worry, it's in this thread.
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Posting this notice as some sites are linking to this thread and not the section or the article, so people are thinking this is the only thread on this.
Remember to use the above link and allow this thread to continue with the Eaglework folk and others updating progress.
I think we need a F.A.Q.
Yes, if the EM Drive thread would be about well-understood science and/or engineering, an FAQ section would be great.
We all want answers, that's why we are here.
Unfortunately there is substantial amount of disagreement as to the measurements and even more disagreement about the theories.
Who is going to be in charge of answering the questions? Are (maybe innocently incorrect or innocently misleading) answers provided by forum volunteers for an unsettled, controversial, Research project like the EM Drive more useful than not having an FAQ section?
How can a FAQ section for unsettled Research in a forum be objectively handled for scientific/engineering accuracy?
Who will give an authoritative answer in a forum?
How is misinformation going to be prevented?
How is agreement on what is the correct answer to a question going to be reached?
Maybe you should elect the most hardcore and knowledgeable proponent and the most hardcore and knowledgeable critic and produce two answers to each question.
additional, federal money.
If Eagleworks thinks this is a bad approach to obtaining additional resources, please let me know why.
This is a question for Eagleworks people:
It seems as though you are short of resources of various types. I propose an online petition, utilizing the "we the people" facility of whitehouse.gov, to ask for more resources to be given to NASA, earmarked for Eagleworks, for the projects of the EM-drive/ME-drive/Q-thruster, and its application to the Alcubierre drive. If you could come up with a proposal, perhaps more focused than I've indicated, this would be the meat of the petition.
I don't mean to over the heads of the NASA Administration, and force them to take money away from other programs for this one. This would be additional, federal money. In my experience, being given more resources than you can use raises expectations beyond what is achievable. Most often, you can't get a project done twice as fast by spending twice as much money on it.
If Eagleworks thinks this is a bad approach to obtaining additional resources, please let me know why.
With great respect,
Robert W. Keyes
I am assuming the microwaves path is something like this?
(http://i.imgur.com/nA1U9X6.png)
Where forces F0 through F16 represent the force of a single microwave at different time intervals.
If the directional force happens at F2, and the opposing force happens from F3 to F16, this still obeys Newtons third law. Isn't the opposing force just being damped like a spring over time?
If M1, M2, ... Mn represent different microwaves, and each Mi is following a similar course, wouldn't this suggest that the directional force will remain positive at a constant rate until the device is shut off causing all forces to cancel?
Not according to Maxwell's linear, isotropic equations.
The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_wave
The energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.
No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.
If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.
Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.
I am assuming the microwaves path is something like this?
(http://i.imgur.com/nA1U9X6.png)
Where forces F0 through F16 represent the force of a single microwave at different time intervals.
If the directional force happens at F2, and the opposing force happens from F3 to F16, this still obeys Newtons third law. Isn't the opposing force just being damped like a spring over time?
If M1, M2, ... Mn represent different microwaves, and each Mi is following a similar course, wouldn't this suggest that the directional force will remain positive at a constant rate until the device is shut off causing all forces to cancel?
Not according to Maxwell's linear, isotropic equations.
The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_wave
The energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.
No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.
If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.
Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.
With all respect, and I am not sure this is much of an issue to point out but I think the model of the waves in the cavity as standing waves may be a bit over-simplified.
1. I think one can look at standing waves as super-imposed traveling waves of opposite direction but this part is likely less significant.
2. Maybe of more significance is the ac power in power lines can be modeled as standing waves but if no one is using power. When power starts being consumed the standing waves begin to travel towards the object consuming the power. The moving bulges of magnetic/electric field can be thought of as transporting power from the power station to the consumer. There should be some traveling of the standing waves bulges from the power supply towards areas of heat loss in the cavity I would assume. I can't say the power dissipated into heat loss is significant but it does seem to buck the perfect standing wave view for me a bit. I do understand on the other hand that it may be a good approximation.
Dr. Rodal:
I missed your question last night on whether the warp-field interferometer cylindrical cavity had any dielectric inside of it. The answer is no it does not, except for the nanometers thick aluminum oxide coating that bare aluminum develops as soon as it is exposed to the oxygen in the air.
Next you asked about whether there where optical windows cut into the center of the cylindrical resonant cavity end caps or not. Well, yes there has to be optical window holes for the 633nm laser light to pass through the 7.23cm gap between the endplates of the aluminum cylindrical cavity. We also added two, three inch long, 0.50" OD by 0.25" (6.35mm) ID threaded aluminum tubes to the resonant cavity endplates, see attached picture, that function as two RF chokes that keep the 1.48 GHz RF from leaking into the lab area. So the laser light passes through these RF choke tubes and the cylindrical cavity where the peak ac E-field of 900kV/m is present along the entire 7.23 cm long laser path while in the resonant cavity and an exponentially reducing E-field in the RF chokes since these are cylindrical waveguides well into their cutoff mode since the RF wavelength at 1.48 GHz is 202.7mm.
BTW, we are going to add optical borosilicate telescope grade flat windows to the ends of the RF chokes when we get around to pulling a vacuum in this 1.48 GHz resonant cavity.
Next a clarification. We used a cylindrical cavity for the warp-field interferometer instead of a frustum shape because we didn't want to create a force with this unit, but instead we needed just a large densification of the Q-V along the active path length of the laser beam while it was traversing the resonant cavity's centerline volume. And this is the main difference between the Q-thruster and a warp-drive. In Dr. White's warp-field conjecture you first have to have an Q-Thruster derived acceleration vector to work on and then you engage the a toroidal warp-field around your accelerating vehicle that then multiples the initial Q-Thruster provided velocity vector by the selected warp-factor. Thus if you have an initial velocity of say 0.01c towards Alpha Centauri with a warp factor of 1,000, your effective velocity becomes 10c while the warp-drive is engaged.
Best, Paul M.
Paul March, have you seen this?
http://arxiv.org/abs/1101.0712
http://arxiv.org/abs/1101.1174
http://www2.cnrs.fr/en/1859.htm
http://phys.org/news/2011-05-when-the-speed-of-light.html
Mulletron:
No I hadn't but thanks for the pointers. So what to you think an asymmetric difference of ~1x10^-18 m/s in velocity of light bring to the table? That the vacuum can be differentially polarized by applied E and B-fields in a volume, in this case dc E&M fields??
Best, Paul M.
Their results seem to support what you guys are reporting from your open air experiments, which is a win, but I don't think we can call this length contraction (even though it might look like it) for sure until the same results are in repeated in vacuum.
These seem to be depressive, defeatist, Kafkaesque responses. I am going to wait to see what people who actually work at Eagleworks say. $25M (just picking a reasonable but arbitrary amount here) might to a lot of money Eagleworks, but for the federal government, that's pin money. Even in a word where governments are overrun by corruption, pettiness, and mismanagement, that doesn't mean that all parts are, all the time.
"Dean Drive" mechanics can offer an insight to EM Drive function.
-snip-
Later more detailed studies showed that the Dean Drive developed no net time- averaged force and that Newton's 3rd Law remained intact.
This is a question for Eagleworks people:
It seems as though you are short of resources of various types. I propose an online petition, utilizing the "we the people" facility of whitehouse.gov, to ask for more resources to be given to NASA, earmarked for Eagleworks, for the projects of the EM-drive/ME-drive/Q-thruster, and its application to the Alcubierre drive. If you could come up with a proposal, perhaps more focused than I've indicated, this would be the meat of the petition.
I don't mean to over the heads of the NASA Administration, and force them to take money away from other programs for this one. This would be additional, federal money. In my experience, being given more resources than you can use raises expectations beyond what is achievable. Most often, you can't get a project done twice as fast by spending twice as much money on it.
Let's say this all works as claimed by Shawyer, and there is indeed scability and improved performance in high Qs.
Theoretically, what would be the smallest size possible for a Q-thrust device?
Rick
Star-Drive, is your current test setup the same as shown in figure 17 of the AIAA paper from July last year, but with the RG-8 cable? If so, you might have issues with the cable. Most high quality RG-8 has a manufacturers minimum bend radius of 4" and can develop some "entertaining" behavior in short order if bent beyond that. You might want to check the cable in its current shape on a network analyzer to verify performance.A very high frequency microwave resonant cavity is commonly known as a "laser".
If the cable is degrading, you might want to look at something like Gore phaseflex cable in that spot. It would give you the flexibility of the RG-142 with the RF performance of the RG-8, and better repeatablity to boot.
Following on what jknuble said about the multipactor-like effect as a possible cause of thrust. http://en.wikipedia.org/wiki/Multipactor_effect I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust.4: enclose the device (complete with the microwave source and, preferably, batteries, provided the pendulum is not too sensitive to shifts in CoM) in a sealed box. Then you can even run your microwave cavity in pressurized SF4 if that helps.
For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.
I can think of 3 ways to debunk this. 1) perhaps that amount of particles going that fast would be noticeable with the naked eye, so this isn't really a valid explanation. 2) stick a detector behind the thruster (are they ionized?). 3) SEM of the surface compared to scraps from the same batch of copper not used in the thrustum.
Just want to run this by the group.
I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either.
The balanced gain and loss stuff came up here. 4th-6th links from top.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on :) ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie.
What's the point of having all that accumulated energy sitting in there static, doing nothing?
We need this thing to ride the razor's edge between gain and loss.
Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
So if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.
There's a lot we can learn from that whispering-gallery research cited.
http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/
http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavities
http://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdf
I'm openly brainstorming here. Would like some feedback.
Just want to run this by the group.
I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either.
The balanced gain and loss stuff came up here. 4th-6th links from top.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on :) ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie.
What's the point of having all that accumulated energy sitting in there static, doing nothing?
We need this thing to ride the razor's edge between gain and loss.
Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
So if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.
There's a lot we can learn from that whispering-gallery research cited.
http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/
http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavities
http://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdf
I'm openly brainstorming here. Would like some feedback.
Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.
The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.
It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.
To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).
If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:
If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?
Just want to run this by the group.
I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either.
The balanced gain and loss stuff came up here. 4th-6th links from top.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on :) ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie.
What's the point of having all that accumulated energy sitting in there static, doing nothing?
We need this thing to ride the razor's edge between gain and loss.
Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
So if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.
There's a lot we can learn from that whispering-gallery research cited.
http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/
http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavities
http://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdf
I'm openly brainstorming here. Would like some feedback.
Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.
The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.
It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.
To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).
If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:
If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?
What I mean is that any attempt to formulate a theory of where the anomalous thrust is coming from which is based on classical electrodynamics will fail. A fully quantum approach is required. What I mean by "other than usual symmetry conditions" is that based off what I've been reading (aka not my own original research), simultaneous breaking of P & T symmetries is required.
Following on what jknuble said about the multipactor-like effect as a possible cause of thrust. http://en.wikipedia.org/wiki/Multipactor_effect I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust.
For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.
I can think of 3 ways to debunk this. 1) perhaps that amount of particles going that fast would be noticeable with the naked eye, so this isn't really a valid explanation. 2) stick a detector behind the thruster (are they ionized?). 3) SEM of the surface compared to scraps from the same batch of copper not used in the thrustum.
Not according to Maxwell's linear, isotropic equations.
The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_wave
The energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.
No net directional thrust for a microwave closed cavity can be explained just using Maxwell's linear, isotropic equations. If the measurements are not an experimental artifact, another explanation is needed.
If the small base would be open, then it would be an inefficient photon rocket, with the microwave photons escaping at the small base end. Less efficient for space propulsion than using a flashlight or a military searchlight as a means of propulsion.
Even for a perfectly collimated photon rocket, the thrust/powerInput of such a photon rocket is orders of magnitude less than what is claimed for these experiments.
With all respect, and I am not sure this is much of an issue to point out but I think the model of the waves in the cavity as standing waves may be a bit over-simplified.
1. I think one can look at standing waves as super-imposed traveling waves of opposite direction but this part is likely less significant.
2. Maybe of more significance is the ac power in power lines can be modeled as standing waves but if no one is using power. When power starts being consumed the standing waves begin to travel towards the object consuming the power. The moving bulges of magnetic/electric field can be thought of as transporting power from the power station to the consumer. There should be some traveling of the standing waves bulges from the power supply towards areas of heat loss in the cavity I would assume. I can't say the power dissipated into heat loss is significant but it does seem to buck the perfect standing wave view for me a bit. I do understand on the other hand that it may be a good approximation.
In ref to the image above, there is wealth of information buried within the earlier pages of this thread. A more accurate representation of what it looks like inside the cavity is available here:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246
Paul March was kind enough to attach the Frustrum modes overview 2A.pdf which has all the mode shapes and characteristics of their test article.
So things are a bit more complicated than photons bouncing around like marbles in a can. For example, I know that I can only excite TM212 and TM311 (thanks @Rodal for modeling this) with my little setup at home.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878
Paul March has shown clearly in his many posts that there is a clear correlation between mode shape and magnitude and direction of thrust. This is where input from RF Engineers would be extremely valuable.
Just food for thought, it is worth going back to page 1 and commenting on the stuff starting there. That way the conversation can keep building on ideas.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=820102;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=820104;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=796989;image)
...
In response to the bold and underlined statements above I was just pointing out that I think we may be losing information by the idea of the standing wave model with out considering the power losses (due heating of the cavity and any propulsion) and the transport of energy by [E^2+B^2] http://hyperphysics.phy-astr.gsu.edu/hbase/electric/engfie.html where the stading wave bulges tend to move towards the areas of consumed energy (heating + sparks + propulsion +ect). I was paralleling it to energy consumption in power lines. There might be some hidden phase relation in here lurking that could suggest em-phase propulsion but that's just speculation.
I agree in the line of thinking of what is going on in the cavity as more of a wave model than thinking of them as marbles bouncing inside the cavity. I admit there might be some parallel to the marbles but I don't see it.
It is interesting to think that as the wave peaks travel towards the small end of the cavity they are being squeezed but if the wave peaks are traveling towards the larger end they are experiencing expansion. It looks like as a result we see the increased B field near the tight end of the cavity and small B field near the big end. I almost want to think of this squeezing as a form of propulsion in the form of resistance of the traveling of the semi-standing waves as they transport energy to areas of heat loss.
Just want to run this by the group.
I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either.
The balanced gain and loss stuff came up here. 4th-6th links from top.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on :) ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie.
What's the point of having all that accumulated energy sitting in there static, doing nothing?
We need this thing to ride the razor's edge between gain and loss.
Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
So if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.
There's a lot we can learn from that whispering-gallery research cited.
http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/
http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavities
http://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdf
I'm openly brainstorming here. Would like some feedback.
Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.
The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.
It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.
To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).
If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:
If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?
Hey everyone!
My name is Kurt Zeller, my colleague Bran Kraft and I are undergraduate Aerospace Engineering students at California Polytechnic State University, San Luis Obispo. (authors of this review: http://www.slideshare.net/KurtZeller/investigation-and-analysis-of-anomalous-electromagnetic-propulsion-devices-41315-46946953 )
We are currently designing an experiment to test a resonant cavity. We have made considerable progress on our own and would like to share our methodology with the forum to gain insight and suggestions before we start purchasing materials. Our primary objective is to demonstrate thrust using a counterbalanced lever. Our secondary objective is to quantify the thrust and make changes to the geometry of the dielectric.
We have recently received funding for a copper cavity, PTFE plate, and aluminum beam. This aluminum beam will have a sharp fulcrum welded to the bottom and the ends will be recessed lower than the fulcrum to put the center of mass closer to the balance point. We anticipate the thrust will be larger than the fulcrum's friction but this is still a concern in our experiment. An additional concern is the tension force from the cables that supply power. We plan to fix these cables above the fulcrum with enough slack to negate this issue. We acknowledge the difficulties in accurately obtaining thrust measurements but are mainly attempting to demonstrate thrust before quantifying it.
The cavity will be made of C10100 Copper alloy tube with two C11000 copper end plates. A symmetric shape was chosen to minimize complications and cost as well as provide a different cavity geometry for comparison. A PTFE plate will machined into discs of varying thickness that fit adequately at the end of the cylinder. We have access to a VNA from our EE department and will use it to determine the resonant frequencies.
We are still awaiting approval for our latest proposal to the Cal Poly committee where we requested $3,500 to rent a 2-3 GHz signal generator, a 50W amplifier, and a spectrum analyzer. We are also planning to implement a matched load to absorb reflected power but are still working with professors to design it.
Because these devices are incredibly expensive, we have been researching how to engineer a microwave oven magnetron into the power source. Unfortunately, the relatively constant frequency will limit the number of resonant modes that can be excited unless our cavity length is adjustable. Furthermore, thermal expansion may be a much greater issue at higher power and resonance may be more difficult to maintain.
In the event that we are approved funding for the rental equipment we will most likely attempt both setups.
We are happy to address questions or concerns and we look forward to any suggestions you may have. We understand Eagleworks is planning a similar experiment and we are hoping to gain more insight into their power delivery system.
We would like to thank all the contributors to this forum who have been a great help and inspiration for us throughout this project.
One of the very few (only ?) reported null result (down to sensitivity) with experiment on propellantless device (not em drive type...) was obtained with a fully self contained test article :Now that was a great experimental setup. Appropriate $ spending for how credible the claims were, yet potentially very sensitive, repeatable, and accurate.
Null Findings on Electromagnetic Inertia Thruster
Experiments using a Torsion Pendulum by Brito, Marini, Galian 2009 (http://enu.kz/repository/2009/AIAA-2009-5070.pdf)
Knowing how to create and see an EM thrust signature, if there is such a thing, is nice. Designing and conducting the experiment to see no thrust signature if there is none is more scientifically valuable IMHO. And at this stage there appear to be more risks in false positives than in false negatives.
But if there's no thrust when the drive is enclosed and if the thrust is diminished, though still present, in a vacuum (when there is no air to push against), doesn't that suggest that the cavity is spewing particles somehow?Right, put kilowatts of power into something, it will heat up and start outgassing something fierce. But also do a lot of other things.
Just want to run this by the group.
I am a believer that thrust doesn't scale ONLY with Q. We even can see that in the data. See the original Nasa paper.
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think I have a good idea for once. I think the "Where is the balanced gain and loss?" thing from the other day is addressed by creating an unstable cavity, aka not high Q, not low Q either.
The balanced gain and loss stuff came up here. 4th-6th links from top.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
I think the trick is to get energy in, put it to work a few thousand times (doing all that quantum wizardry I posted papers on :) ), then let it go as heat, which will inevitably happen as photons are red shifted and fall out of resonance. High Q is a baddie. Low Q is a baddie.
What's the point of having all that accumulated energy sitting in there static, doing nothing?
We need this thing to ride the razor's edge between gain and loss.
Also, what made this kinda click with me is what Mr. Shawyer said below. The Cullen paper he mentioned is shared here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
So if this passes the smell test, how is the next question. Seems like not having the dielectric covering the entire small end (vs just a small patch) might be a good thing to try. I'm sure there's a ton of ways to do this.
There's a lot we can learn from that whispering-gallery research cited.
http://revolution-green.com/optics-breakthrough-demonstrates-new-behaviors-physics/
http://www.researchgate.net/publication/262451086_Paritytime-symmetric_whispering-gallery_microcavities
http://arxiv.org/ftp/arxiv/papers/1308/1308.4564.pdf
I'm openly brainstorming here. Would like some feedback.
Shawyer's explanation does not pass the smell test, and is not adressed by the Cullen paper you linked. Look for example at figure 5. There is a movable piston at the end of the waveguide T-junction, which is subject to radiation pressure. The piston will exert a (Newton's 3rd law) reaction force, and so momentum is conserved.
The EM drive is a fully enclosed cavity. The radiation inside will reflect off the walls and create some strain in the copper, but the net force integrated by the surface (given by the integral of the Poynting vector) has a time average of 0, as has been demonstrated mathematically many many times.
It is absolutely true that one can view standing waves as linear superpositions of traveling waves. This is just a different way of saying that Maxwell's equations are linear. Rodal's analysis is true whether one thinks of the fields as standing or superpositions of traveling waves. There is nothing besides the stress-energy tensor in the classical theory of electromagnetism.
To be clear: there is NO explanation for any increase in momentum of the drive to be found in classical theory (including Special Relativity through Maxwell's equations).
If there is an actual effect, then it must be caused by the coupling of electromagnetic fields to some other heretofore unobserved field. Even if such a coupling could be made in a way that is Lorentz invariant, it should have been detectable very easily at particle colliders. So again I ask:
If there is some effect here, why has it not been observed in far more precise experiments that probe the exact same physics?
Hmmm... See: http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
Edit: The self acceleration of photons, on the other hand, is old news.
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
But if there's no thrust when the drive is enclosed and if the thrust is diminished, though still present, in a vacuum (when there is no air to push against), doesn't that suggest that the cavity is spewing particles somehow?Right, put kilowatts of power into something, it will heat up and start outgassing something fierce. But also do a lot of other things.
2.5kW is a LOT of power. If it's all essentially absorbed by the cone, then it gets converted into heat. 2.5kW is like the power output of an oven or like 40 incandescent light bulbs. Especially in a vacuum, you're going to heat up your device to hundreds of degrees. If this gets transferred to the thrust-measuring arm at all (which it likely would), you're going to change the resistance of your strain gauge, thus giving you a false thrust reading.
Remember that strain gauges are just copper wire, and so acts just as well as a kind of thermometer. A temperature change (unless super, super carefully canceled out--almost impossible to do if there's a large temperature gradient on the gauge itself) will show up as a change in resistance, just like force will.
However, in 2010, Prof. Juan Yang in China began publishing about her research into EM Drive technology, culminating in her 2012 paper reporting higher input power (2.5kW)
My take:
There is a potential gradient formed within the cavity causing one end of the device to fall toward the other. The energy density at each end would differ due to the geometry leaving one side with a slightly higher mass-energy density than the other, creating the gradient.
Nathan Rogers
James, thank you for the interesting, thought-provoking discussion. :)
You accurately and completely answered the questions I asked. Unfortunately, I didn't ask my questions very well. :)
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1354235#msg1354235
A constant-amplitude standing wave does indeed result in a zero time-average Poynting vector. However, I am questioning your conclusion that a constant-amplitude standing wave accurately represents a real resonator cavity such as the as-tested EM drive frustum. Instead, I would expect a decaying amplitude standing wave to be a more accurate model/plot (as would be derived from a full solution to Maxwell's equations with proper boundary conditions such as non-zero resistance, etc).
Once a time-decaying standing wave is used for computation of a time-average Poynting vector, I'm having trouble seeing how the incident and reflected energy can perfectly cancel and become zero. I'll readily admit I may be oversimplifying and/or missing a fundamental concept; it's been a long time since I actually computed time constants for resonant cavities using Maxwell's equations and non-zero resistances.
Phrased a bit differently, I believe only excited modes with current/thermal losses in the base plates will significantly weight the direction of the time-average Poynting vector. Each pair of incident/reflected waves would have a larger energy loss at the base plate with the excited E field (and therefore excited currents) than the energy loss at the opposing base plate. For modes with near-zero E fields at the base plate boundaries, each incident/reflected wave pair would have a near equal energy delta regardless of which base plate they came in contact with; the resulting time-averaged direction would be random and magnitude limited by the energy lost in the very first reflection (randomly either the large or small base, with a magnitude very close to zero).
I view this Poynting vector discussion to be completely independent of whether Dr. White's QV interactions, or some other classical physics can explain the EM drive anomalous thrust. Just wanted to chime in on a what appeared to be the use of a constant-amplitude standing wave to describe a real-world system. Your earlier observation of a non-zero time averaged Poynting vector seemed like a reasonable statement given that only excited modes with current/thermal losses in the base plates would quickly diverge from the simplified constant-amplitude standing wave model.
Regards,
James
Let's calculate some numbers to estimate what we are discussing.
The electromagnetic fields transition from the air or vacuum medium (where they are out of phase by 90 degrees) to the copper over an extremely small distance: a boundary layer. The skin depth for copper at 2 GHz is 1.48 micrometers = 58.2 microinches . When showing the Poynting vector field distribution this distance is infinitesimal compared to the rest of the cavity. In this very small distance inside the copper (1.48 micrometers ) the electromagnetic fields in the copper are out of phase by approximately 45 degrees (due to the high conductivity of copper). For a transverse magnetic (TM) mode, the only electromagnetic field component that is continuous across the vacuum/copper interface is the electric field component tangent to the copper surface.
More interestingly (for this thread's discussion due to the significance that the NASA experimenters have placed on the dielectric being responsible for providing the measured thrust) is what happens in the High Density PolyEthylene (HDPE) dielectric polymer insert. Because the dimensions of the dielectric are not negligible compared to the EM Drive's dimension, and the dielectric is not modeled as just a boundary condition.
The loss tangent of HDPE is reported to be
tan delta = 0.0004
Therefore the intrinsic impedance angle is
intrinsic impedance angle =(ArcTan[0.0004])/2
Therefore, inside the HDPE dielectric the electric and magnetic fields, instead of being out of phase by 90 degrees (as they are in the air or vacuum medium), will be out of phase by:
90 - (ArcTan[0.0004])/2 = 89.9998 degrees
This phase angle (89.9998 degrees) will show practically no visual difference with 90 degrees at the resolution of the following image :
(http://www-ssc.igpp.ucla.edu/personnel/russell/papers/skip_ed/fig9.gif)
The Poynting vector inside the HDPE dielectric, instead of having a zero time average, will have the following factor multiplying ExB/mu :
Cos[90 - (ArcTan[0.0004])/2]/2 = 0.0000999999940000637
So, inside the HDPE polymer dielectric the Poynting vector has this small magnitude over a period (or multiples thereof).
So, the extent of this approximation, for the HDPE dielectric is about 0.01 % (which is negligible in comparison to several other approximations).
Now, let's examine what this (very small intensity Poynting vector time average) means, concerning the discussion in this EM Drive.
If one were to posit that the EM Drive's thrust is due to the very small magnitude of the time average of the Poynting vector due to these thermal losses (in the HDPE dielectric or in the copper):
1) It would mean that there should be more thrust with lower Q. This is the complete opposite of what the experimenters like Shawyer claims (Shawyer claims that the higher the Q, the greater the thrust). Notice that
Tan [loss angle] = Tan[ 2 impedance angle ]= 1/Q
2) All the equations proposed so far (by Shawyer, McCulloch and @Notsosureofit) have predicted thrust proportional to Q. This is the complete opposite of what such a Poynting vector would predict (it would predict thrust proportional to 1/Q instead), because
Tan delta= 1/Q
measured Q effective tan delta
7320 1.366* 10 ^(-4)
22000 4.545* 10 ^(-5)
10^6 10^(-7)
3) It would mean that experimenters like Shawyer and Fetta are in the completely wrong track pursuing superconducting EM Drives, as superconducting EM Drives would lead to practically no thrust (the opposite of what they claim) because superconducting EM Drives would display practically no heat losses and hence zero time average Poynting vector.
4) Considering the HDPE dielectric acting as a sink (energy flowing from the EM Drive towards the HDPE where the energy is dissipated internally in the dielectric polymer due to its tandelta and hence irretrievably lost instead of being reflected), the Poynting vector would be directed towards the HDPE dielectric, that is towards the small base, and hence the EM Drive should experience a recoil force and acceleration towards the big base. This is the opposite direction force found in NASA's experiments with the dielectric. (Recall that NASA Eagleworks found no thrust force with mode TE012 without a HDPE dielectric and that with the HDPE dielectric inserted at the small base they found a force and acceleration directed towards the small base.)
I showed the fact that boundary conditions for the transverse electric (TE) electromagnetic mode shapes all Poynting vector components vanish at the walls of the EM Drive and the fact that for mode shape TE012 without the dielectric the Poynting vector is self-cancelling. This is consistent with NASA Eagleworks results and supports NASA Eagleworks preference for the transverse magnetic (TM) modes over the transverse electric (TE) modes.
Excellent work posting the Shawyer emails.
Question on your test rig. You are aware, according to Shawyer, a non moving EMDrive will not generate any thrust and that it must move to enable thrust to be indirectly measured? Are you planning to use a rotary test?
http://www.emdrive.com/EmDriveForceMeasurement.pdf
Additionally his test with a dielectric, resulted in reduced thrust generation.
http://www.emdrive.com/iac2014presentation.pdf - page 2
Wish you all the best of luck. Would be interested to replicate your device.
Because the thruster is at rest, no force will be measured on the load cell.
i.e. F = T-R = 0
It therefore appears that a force measurement can only be made in a dynamic environment, ideally by allowing the thruster to accelerate, measuring that acceleration, and then calculating the thrust from T = -Ma.
Please review page 2TheTraveler keeps sending me PMs which are good stuff. He needs to post in open forum. He's essentially saying the dielectric section also serves to "bootstrap" this initial acceleration requirement.
http://www.emdrive.com/iac2014presentation.pdf
Note the use of a dielectric resulted in weaker thrust and in the opposite direction, line 3, to a non dielectric EMDrive, line 4, 5 & 6.
This suggest EW may have found a new way to gen thrust, via a dielectric, that appears to work when the test device is fixed/stationary and in the opposite direction to a classic EMDrive.
Interesting.
One question, regarding Mr. Shawyer's understanding of what's going on in his EM-drive:OK, I am going to take a (partial)shot at this. I am a complete idiot as far as maths go, but I did remember some of it from school. I hope this can give you a handle at least, so please be gentle...
Let's pretend we are a photon. We are traveling at c. Due to Lorentz-contraction of space in our traveling direction, how does the universe look like for us, a photon? I think that the universe actually appears as a sort of surface in our traveling direction, due to the maximum Lorentz contraction of space in front of us.
The question is: For a photon, moving at c, how does the inner geometry of an EM-drive frustum really look like? Could there be an apparent nonlinearity, from the viewpoint of a photon, within an EM-drive device, that we in our everyday, non-Lorentz contracted world don't perceive? Is there someone on the forum who can do the math that projects how the maximum-Lorentz contracted universe looks like for a photon, and apply this to an EM-drive environment?
Best,
CW
Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.
so in effect 0.
To be completely honest, I don't know. But that's how I would theorize it. Please realize I am in no way a scientist or physicist. I am a simple IT technician that loves to gobble up threads like this :)Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.Quoteso in effect 0.
So nonzero? Say outside the bandwidth of a very narrow bandwidth cavity?
Here Shawyer compares 7 devices, some classic EMDrives, some with just a dielectic & the superconducting LN cooled Cannae drive.
It is important to note the direction of generated thrust as dielectics apparently generate thrust in the opposite direction to that of EMDrives.
I do note the EW test of a Cannae like device was not tested at cryo temp nor had superconducting interior lining and had an added dielectic. So was not a test of a true Cannae device.
From Shawyer, EW should not expect to see any thrust from an EMDrive like test device when tested fixed, not allowed to accelerate, without added dielectic. Which is what was observed. Static thrust was not measured, with the EW EMDrive like device until a dielectic was added.
Appears EW have discovered a new way to gen thrust in a fixed device. Use a dielectric. From Shawyer device summary, line 1, it appears all that may be needed is a short section of resonate pipe with a dielectic stuck in one end. IE EW Cannae test device minus the cavity.
However as the dielectric thrust is weaker than the EMDrive thrust and in the opposite thrust direction to the classic EMDrive thrust direction, putting a dielectric into an accelerating EMDrive may reduce the overall delivered thrust and effective cavity Q as would be seen by the classic EMDrive operational mode.
Is Shawyer giving away spoilers?
https://twitter.com/elonmusk/status/594756342641922048I don't use twitter, but perhaps you (or somebody else in the forum) does. If such is the case, can you (or somebody else) twitter him back a message informing him that this article contains much newer information ? :
But why in the world did @ElonMusk link to an article from August 2014? That is soooo last year.
https://twitter.com/elonmusk/status/594756342641922048I don't use twitter, but perhaps you (or somebody else in the forum) does. If such is the case, can you (or somebody else) twitter him back a message informing him that this article contains much newer information ? :
But why in the world did @ElonMusk link to an article from August 2014? That is soooo last year.
http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/
...I would not bet on that. The uncivil level of attack displayed by several new posters in this thread during the last few days has been such that I would not be surprised if Star-Drive decides not to post any further Eagleworks test information here. These uncivil attacks are launched by anonymous posters that hide behind monickers without ever revealing their real names. I very much doubt that these uncivil posters would dare to express themselves this way, face-to-face in a public presentation, as in an AIAA meeting, for example. I very much doubt that they would express themselves that way in writing if they would do it under their real name. It is certainly conduct never seen at professional meetings or in academia.
I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
The device you pictured is the 1st Dynamic Test unit (data apparently not in the summary):Here Shawyer compares 7 devices, some classic EMDrives, some with just a dielectic & the superconducting LN cooled Cannae drive.
It is important to note the direction of generated thrust as dielectrics apparently generate thrust in the opposite direction to that of EMDrives.
I do note the EW test of a Cannae like device was not tested at cryo temp nor had superconducting interior lining and had an added dielectic. So was not a test of a true Cannae device.
From Shawyer, EW should not expect to see any thrust from an EMDrive like test device when tested fixed, not allowed to accelerate, without added dielectic. Which is what was observed. Static thrust was not measured, with the EW EMDrive like device until a dielectic was added.
Appears EW have discovered a new way to gen thrust in a fixed device. Use a dielectric. From Shawyer device summary, line 1, it appears all that may be needed is a short section of resonate pipe with a dielectic stuck in one end. IE EW Cannae test device minus the cavity.
However as the dielectric thrust is weaker than the EMDrive thrust and in the opposite thrust direction to the classic EMDrive thrust direction, putting a dielectric into an accelerating EMDrive may reduce the overall delivered thrust and effective cavity Q as would be seen by the classic EMDrive operational mode.
Is Shawyer giving away spoilers?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828231;image)
Thank you for your post, as it gives me the opportunity to ask again a couple of questions that are unanswered so far. Perhaps you can answer them:
1) Shawyer reported in the above graph, that his Demonstrator engine is the only EM Drive so far that has shown forces in BOTH directions, towards the small end as well as towards the large end.
1a) What does Shawyer mean by this? Does he mean that the Demonstrator engine displayed, and he measured, forces simultaneously in both directions? But as the forces in both directions are almost equal, that would mean practically no net force. That doesn't seem to make sense as the Demonstrator engine is the only one that had a force large enough that it could move the whole assembly as shown in a video:
https://www.youtube.com/watch?v=57q3_aRiUXs
1b) Did Shawyer measure a force towards the big end in some tests and a force towards the small end in other tests? If so, what made the difference between the tests? Is the change random, unpredictable and unexplained? (Hopefully not). If the change in force direction can be deliberately controlled, how was Shawyer able to change the force direction for the Demonstrator engine? Did he have to move something? (like the location of the dielectric)? Was there a dielectric in the Demonstrator engine? Or did he just accomplish this change of force direction by changing the exciting frequency (and thereby changing the mode shape)?
2) Shawyer defines the measured "thrust force" in the opposite direction to the direction of motion of the EM Drive. This is completely the opposite of NASA Eagleworks that defines the thrust force in the same direction as the motion of the EM Drive. Can you reconcile and make sense of these two opposite, contradictory definitions and measurements?
Thanks
Might be useful to listen to what Shawyer has to say:I listened to those some time ago, and my recollection is that he does not answer this question in that inverview, that still remains unanswered:
http://www.emdrive.com/interview.html
We need to ask Shawyer as maybe a typo.Might be useful to listen to what Shawyer has to say:I listened to those some time ago, and my recollection is that he does not answer this question in that inverview, that still remains unanswered:
http://www.emdrive.com/interview.html
How did Shawyer achieve thrust in opposite directions for the same Demonstrator engine?
We can safely bet that the excellent moderators here will take good care of Mr. Shawyer so that he can explain how this thing works in his own words.Please make that happen.
We need to ask Shawyer as maybe a typo.Might be useful to listen to what Shawyer has to say:I listened to those some time ago, and my recollection is that he does not answer this question in that inverview, that still remains unanswered:
http://www.emdrive.com/interview.html
How did Shawyer achieve thrust in opposite directions for the same Demonstrator engine?
Maybe Mulletron can ask him as he has email contact and the data is in the public domain?
We know from the 2014 summary that there was no dielectric in the Demonstrator. From the SPR site data on the Demonstrator Engine we know it can alter it's cavity length to assist tuning but that should not alter thrust direction.We need to ask Shawyer as maybe a typo.Might be useful to listen to what Shawyer has to say:I listened to those some time ago, and my recollection is that he does not answer this question in that inverview, that still remains unanswered:
http://www.emdrive.com/interview.html
How did Shawyer achieve thrust in opposite directions for the same Demonstrator engine?
Maybe Mulletron can ask him as he has email contact and the data is in the public domain?
I don't think that we can dismiss this as a typo (and therefore I agree with you that it should be pursued with a question to Shawyer) because in a previous discussion in this thread I had addressed this question to Star-Drive, who answered that as far as he knew there were two ways to change the direction of thrust of EM Drives: a) to change the location of the dielectric polymer insert and b) to change the mode shape. Star-Drive posted his experimental evidence for a) and wrote that he had no experimental evidence for b) which (to my mind) means that this is information he may know from other experiments.
90 seconds of thrust at 326mN/kW over a power input range of 150w to 450W is not something that is hard to test for.
SPR say they built & qualified this Flight Thruster for Boeing.
http://www.emdrive.com/flightprogramme.html
So where is it? Why don't EW have it to test?
...Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Yes I know of the Boeing reports. As Shawyer said in his vid, "It Went Dark".90 seconds of thrust at 326mN/kW over a power input range of 150w to 450W is not something that is hard to test for.
SPR say they built & qualified this Flight Thruster for Boeing.
http://www.emdrive.com/flightprogramme.html
So where is it? Why don't EW have it to test?
My recollection is that it was earlier reported in these threads that Boeing decided to discontinue any further work on it. Do you have any further (or different) information ?
Concerning Eagleworks working with Shawyer, Eagleworks is already under severe budget constraints, for NASA to enter into an R&D agreement with a foreign company pursuing intellectual property rights is not a trivial endeavor as it would require IP negotiations and agreement from NASA's IP department, so that is fully understandable.
... Seems fairly easy for Boeing to send a SPR Flight Thruster to EW to test?No, NASA cannot just "accept" a SPR Flight Thruster to test just like that, when SPR is a foreign company pursuing intellectual property rights. Even Ford Motor Company will not accept any letter from any inventor disclosing an invention and much less accept to test in their R&D department a rig from a company pursuing IP rights. It would need to involve an IP agreement.
Hi,For item one i can help. It is not a pendulum. It is a torsion balance. Great pains have been taken to eliminate all sources of error including electromagnetic related effects or at least quantify them and deduct them from the data as much as possible. You cannot be sure though that there isn't some factor you have not thought of at work. But with all the scrutiny this is getting and has got you can be sure that the probability of some unknown but mundane source of error is pretty low.
I have two questions:
1. if the pendulum that measures the force is made of metal, is it properly shielded from electro magnetism?
2. why, in the second run there was much less thrust? (this was an experiment where more measures were taken against confounding variables, so does the drop in thrust indicate any confounding variable to have played a major role in the thrust measured in the first experment?
91.2 µN at 17 W of input power
50 µN with 50 W of input power
thanks,
Siem
Except all the SPR tech was acquired by Boeing. So you are saying that if Boeing wanted to ask EW to test a Flight Thruster they had in their possession and was their paid for property, they could not do it? Surely Boeing can use other test labs to verify claimed performance? I mean Boeing did acquire all the SPR tech. Doubt they would do that without being sure it worked. Which implies it was tested and probably by several labs.... Seems fairly easy for Boeing to send a SPR Flight Thruster to EW to test?No, NASA cannot just "accept" a SPR Flight Thruster to test just like that, when SPR is a foreign company pursuing intellectual property rights. Even Ford Motor Company will not accept any letter from any inventor disclosing an invention and much less accept to test in their R&D department a rig from a company pursuing IP rights. It would involve an IP agreement.
Yes, based on my experience being in charge of R&D departments in private companies and managing Intellectual Property negotiations and litigation, I would expect that for NASA to test devices from companies pursuing intellectual property rights it would involve a negotiation of an IP agreement........ Seems fairly easy for Boeing to send a SPR Flight Thruster to EW to test?No, NASA cannot just "accept" a SPR Flight Thruster to test just like that, when SPR is a foreign company pursuing intellectual property rights. Even Ford Motor Company will not accept any letter from any inventor disclosing an invention and much less accept to test in their R&D department a rig from a company pursuing IP rights. It would involve an IP agreement.
The SPR/Boeing deal was done and dusted in 2010.Yes, based on my experience being in charge of R&D departments in private companies and managing Intellectual Property negotiations and litigation, I would expect that for NASA to test devices from companies pursuing intellectual property rights it would involve a negotiation of an IP agreement........ Seems fairly easy for Boeing to send a SPR Flight Thruster to EW to test?No, NASA cannot just "accept" a SPR Flight Thruster to test just like that, when SPR is a foreign company pursuing intellectual property rights. Even Ford Motor Company will not accept any letter from any inventor disclosing an invention and much less accept to test in their R&D department a rig from a company pursuing IP rights. It would involve an IP agreement.
Are you saying SPR is currently pursuing Boeing for intellectual property rights? My info says the deal was done and dusted many years ago and Shawyer has moved on.
Yes, based on my experience being in charge of R&D departments in private companies and managing Intellectual Property negotiations and litigation, I would expect that for NASA to test devices from companies pursuing intellectual property rights it would involve a negotiation of an IP agreement.
...Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
...Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
You cannot address the theory without addressing the frame problem.
And no I can't address the frame problem of the self accelerating particle. At least not from a verbal description. But I bet dollars to donuts that they can. If they can't their work is nonsense.
Actually I doubt there is a frame problem involved.
...Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
You cannot address the theory without addressing the frame problem.
And no I can't address the frame problem of the self accelerating particle. At least not from a verbal description. But I bet dollars to donuts that they can. If they can't their work is nonsense.
Actually I doubt there is a frame problem involved.
The center of gravity for self-accelerating particles cannot be defined, because the Airy function is not square integrable: it corresponds to an infinite number of particles, just like the plane wave and other wave functions in scattering theory.
...Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
You cannot address the theory without addressing the frame problem.
And no I can't address the frame problem of the self accelerating particle. At least not from a verbal description. But I bet dollars to donuts that they can. If they can't their work is nonsense.
Actually I doubt there is a frame problem involved.
OK we fully agree on that. But why is it necessary that if the EM Drive were to "work" as space propulsion in some restricted sense, that it necessarily would involve a frame problem? For example, the EM Drive could be given experimental force measurements just due to outgassing (which also would work in space -for a reduced amount of time :) ), which is a perfectly classical explanation. There are many other theories besides Dr. White's and Shawyer's....Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
You cannot address the theory without addressing the frame problem.
And no I can't address the frame problem of the self accelerating particle. At least not from a verbal description. But I bet dollars to donuts that they can. If they can't their work is nonsense.
Actually I doubt there is a frame problem involved.
The center of gravity for self-accelerating particles cannot be defined, because the Airy function is not square integrable: it corresponds to an infinite number of particles, just like the plane wave and other wave functions in scattering theory.
Great, but unless it behaves differently depending on what frame of reference it is in it isn't a frame problem. For example if it works differently on Mars than on Earth because of the different orbital velocity.
OK we fully agree on that. But why is it necessary that if the EM Drive were to "work" as space propulsion in some restricted sense, that it necessarily would involve a frame problem? For example, the EM Drive could be given experimental force measurements just due to outgassing (which also would work in space -for a reduced amount of time :) ), which is a perfectly classical explanation. There are many other theories besides Dr. White's and Shawyer's....Nobody here is addressing the frame problem either.I am not addressing the frame problem at this point in time because I think it is very premature to deal with future applications (for which the frame problem I agree is indeed important to address) when we are still discussing the experiments and the working theory.
Can you address the frame problem for self-accelerating particles (shown to be a valid solution of Schrodinger's equation, for at least 36 years) ?
http://newsoffice.mit.edu/2015/self-accelerating-particles-0120
http://www.nature.com/ncomms/2014/141030/ncomms6189/abs/ncomms6189.html
You cannot address the theory without addressing the frame problem.
And no I can't address the frame problem of the self accelerating particle. At least not from a verbal description. But I bet dollars to donuts that they can. If they can't their work is nonsense.
Actually I doubt there is a frame problem involved.
The center of gravity for self-accelerating particles cannot be defined, because the Airy function is not square integrable: it corresponds to an infinite number of particles, just like the plane wave and other wave functions in scattering theory.
Great, but unless it behaves differently depending on what frame of reference it is in it isn't a frame problem. For example if it works differently on Mars than on Earth because of the different orbital velocity.
Shawyer developed a theory and built a device to test it. If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. If he cannot see and address the violation of Galilean relativity then I wouldn't trust him to test a light bulb.This is wrong in so many different ways I don't know where to start...
...If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. ..Science is full of experimental results that were found by accident, without meeting the theoretical expectations of the experimenter. Do I need to name them? Probably not, I'm sure you know about them too.
Shawyer shows how the EM Drive can act as a Motor or Generator depending on the direction of movement relative to the EM Drive: http://www.emdrive.com/IAC13paper17254.v2.pdfWe need to ask Shawyer as maybe a typo.Might be useful to listen to what Shawyer has to say:I listened to those some time ago, and my recollection is that he does not answer this question in that inverview, that still remains unanswered:
http://www.emdrive.com/interview.html
How did Shawyer achieve thrust in opposite directions for the same Demonstrator engine?
Maybe Mulletron can ask him as he has email contact and the data is in the public domain?
I'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?These?
If it works by reacting against something like the quantum vacuum you have to either violate relativity or COE.
In order for White's proposed explanation to make any sense at all, you need to assume 3 things: ...
Is there a quantitative agreement between reports in respect of certain variables?...If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. ..Science is full of experimental results that were found by accident, without meeting the theoretical expectations of the experimenter. Do I need to name them? Probably not, I'm sure you know about them too.
You can state that it is "unlikely" in some sense, but I haven't seen a Bayesian analysis of what is the probability (do you know of any such Bayesian analysis ?).
In any case, whatever the probability has to be based on at least three independent testing centers: the reason why this is being discussed in this forum, and I'm still here is not just because of Shawyer's experimental claims, but it is mainly due to NASA's Dr. White's report and also due to Prof. Yang's experiments in China.
...I would not bet on that. The uncivil level of attack displayed by several new posters in this thread during the last few days has been such that I would not be surprised if Star-Drive decides not to post any further Eagleworks test information here. These uncivil attacks are launched by anonymous posters that hide behind monickers without ever revealing their real names. I very much doubt that these uncivil posters would dare to express themselves this way, face-to-face in a public presentation, as in an AIAA meeting, for example. I very much doubt that they would express themselves that way in writing if they would do it under their real name. It is certainly conduct never seen at professional meetings or in academia.
I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
I'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?
...
If it works by reacting against something like the quantum vacuum you have to either violate relativity or COE.
Interacting with the quantum vacuum doesn't require violating COE or COM, but it still wouldn't generate any thrust without making additional assumptions that are even harder to swallow, as I discuss here:In order for White's proposed explanation to make any sense at all, you need to assume 3 things: ...
...I would not bet on that. The uncivil level of attack displayed by several new posters in this thread during the last few days has been such that I would not be surprised if Star-Drive decides not to post any further Eagleworks test information here. These uncivil attacks are launched by anonymous posters that hide behind monickers without ever revealing their real names. I very much doubt that these uncivil posters would dare to express themselves this way, face-to-face in a public presentation, as in an AIAA meeting, for example. I very much doubt that they would express themselves that way in writing if they would do it under their real name. It is certainly conduct never seen at professional meetings or in academia.
I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
I must say I'm rather perplexed and puzzled by the sudden hostility that some of the newer participants demonstrate...
There is absolutely nothing wrong with being skeptic but i thought that curiosity was one of the key characteristics of being a scientist/researcher/engineer.
There is no better way to make progress then to have a thesis and antithesis collide in a civil manner.
I really do not understand what can be obtained or achieved by aggressively attacking people or their ideas. If you aim to disprove a theory then all you need to do is mass enough evidence that their theory is flawed.
Personally I find it still too early trying to come up with theories until the effect has been validated or not.
For me the most compelling evidence so far is still the 2007 rotating Demonstrator video by R Shawyer.
All we can do now is wait for Eagleworks to duplicate that test (and improve on some of the possible setup flaws, like hot jet exhaust nullification).
If the test fails, then the credibility of the device will get a serious hit...
If the test succeeds, it will most likely be a turning point in the research (and funding) of the EM drive.
So, instead of shooting lead at each other, why don't we just all relax and be supportive to the Eagleworks team so they can finalize that crucial test by July?
Pro or contra, you'll have your answer by July...
That said, it was to foresee that giving more publicity to the research through the NASA publication article, would attract some of the most aggressive opinionated people inhere.
On the positive side however, it also attracted some very much needed new participants that have clearly high level qualifications... (be them pro or contra, it doesn't matter)
I suppose it is up to the mods to weed out the offensive ones...
As for mr Shawyer, i think it is already obvious that he will not engage into the discussion here, partially because of the engagements he already has with other parties, as he explained in that private conversation, partially because he had his share of abusive language in the past....
....eagerly anticipating the next , high power test from Eagleworks... 8)
Shawyer has been doing this for longer than anybody. My eng gut says follow Shaywer's lead as he has already gone down many dead ends. Why try to reinvent the wheel and repeat his failures?
...I would not bet on that. The uncivil level of attack displayed by several new posters in this thread during the last few days has been such that I would not be surprised if Star-Drive decides not to post any further Eagleworks test information here. These uncivil attacks are launched by anonymous posters that hide behind monickers without ever revealing their real names. I very much doubt that these uncivil posters would dare to express themselves this way, face-to-face in a public presentation, as in an AIAA meeting, for example. I very much doubt that they would express themselves that way in writing if they would do it under their real name. It is certainly conduct never seen at professional meetings or in academia.
I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
I must say I'm rather perplexed and puzzled by the sudden hostility that some of the newer participants demonstrate...
There is absolutely nothing wrong with being skeptic but i thought that curiosity was one of the key characteristics of being a scientist/researcher/engineer.
There is no better way to make progress then to have a thesis and antithesis collide in a civil manner.
I really do not understand what can be obtained or achieved by aggressively attacking people or their ideas. If you aim to disprove a theory then all you need to do is mass enough evidence that their theory is flawed.
Personally I find it still too early trying to come up with theories until the effect has been validated or not.
For me the most compelling evidence so far is still the 2007 rotating Demonstrator video by R Shawyer.
All we can do now is wait for Eagleworks to duplicate that test (and improve on some of the possible setup flaws, like hot jet exhaust nullification).
If the test fails, then the credibility of the device will get a serious hit...
If the test succeeds, it will most likely be a turning point in the research (and funding) of the EM drive.
So, instead of shooting lead at each other, why don't we just all relax and be supportive to the Eagleworks team so they can finalize that crucial test by July?
Pro or contra, you'll have your answer by July...
That said, it was to foresee that giving more publicity to the research through the NASA publication article, would attract some of the most aggressive opinionated people inhere.
On the positive side however, it also attracted some very much needed new participants that have clearly high level qualifications... (be them pro or contra, it doesn't matter)
I suppose it is up to the mods to weed out the offensive ones...
As for mr Shawyer, i think it is already obvious that he will not engage into the discussion here, partially because of the engagements he already has with other parties, as he explained in that private conversation, partially because he had his share of abusive language in the past....
....eagerly anticipating the next , high power test from Eagleworks... 8)
Not according to Maxwell's linear, isotropic equations.
The small base of the EM Drive is not open. It is a closed cavity. As such, the waves inside it are not travelling waves, but standing waves. See this: http://en.wikipedia.org/wiki/Standing_wave
The energy flux is pointed towards one end during half a (Poynting vector) period and it is pointed towards the opposite end during the next half-period. Hence the net energy flux over a whole period is completely self-cancelling.
...
...the ac power in power lines can be modeled as standing waves but if no one is using power. When power starts being consumed the standing waves begin to travel towards the object consuming the power. The moving bulges of magnetic/electric field can be thought of as transporting power from the power station to the consumer. There should be some traveling of the standing waves bulges from the power supply towards areas of heat loss in the cavity I would assume. I can't say the power dissipated into heat loss is significant but it does seem to buck the perfect standing wave view for me a bit...
In ref to the image above, there is wealth of information buried within the earlier pages of this thread. A more accurate representation of what it looks like inside the cavity is available here:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246
Paul March was kind enough to attach the Frustrum modes overview 2A.pdf which has all the mode shapes and characteristics of their test article.
So things are a bit more complicated than photons bouncing around like marbles in a can. For example, I know that I can only excite TM212 and TM311 (thanks @Rodal for modeling this) with my little setup at home.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878
Paul March has shown clearly in his many posts that there is a clear correlation between mode shape and magnitude and direction of thrust. This is where input from RF Engineers would be extremely valuable.
Just food for thought, it is worth going back to page 1 and commenting on the stuff starting there. That way the conversation can keep building on ideas.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=820102;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=820104;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=796989;image)
...I think we may be losing information by the idea of the standing wave model with out considering the power losses (due heating of the cavity and any propulsion) and the transport of energy by [E^2+B^2] http://hyperphysics.phy-astr.gsu.edu/hbase/electric/engfie.html where the stading wave bulges tend to move towards the areas of consumed energy (heating + sparks + propulsion +ect). I was paralleling it to energy consumption in power lines...
I agree in the line of thinking of what is going on in the cavity as more of a wave model than thinking of them as marbles bouncing inside the cavity...
It is interesting to note that as the wave modes travel towards the small end of the cavity they are being squeezed but if the wave peaks are traveling towards the larger end they are experiencing expansion. It looks like as a result we see the increased B field near the tight end of the cavity and small B field near the big end. I almost want to think of this squeezing as a form of propulsion in the form of resistance of the traveling of the semi-standing waves as they transport energy to areas of heat loss.
Can you please answer, according to your conjecture,when the thrust force is measured towards the small end of the truncated cone:
1) Are there any particles being emitted, according to your conjecture, out of the cavity in the axial direction towards the big base ?
[If nothing is being emitted, then there cannot be any propulsion, because it would violate conservation of momentum. If nothing is being emitted, please skip the next question]
2) what particle is being emitted, out of the cavity, in the axial direction towards the big base ?
[for example, if you conjecture that photons are being emitted, even if that conjecture would be true, it would be contradicted by what is claimed, because what is claimed is a thrust thousands of times better than the thrust of a perfectly collimated photon rocket]
So, if you are attempting to explain the claimed thrust just based on Maxwell's equations, I still don't understand your conjecture. If I misunderstood something, please correct me. Thanks.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828276;image)1) In your image, you have a T-Junction from a waveguide into the EM Drive truncated cone.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828276;image)In your image, you have a T-Junction from a waveguide into the EM Drive truncated cone.
Although Prof. Yang used such construction (for at least part of her tests), to my knowledge, NASA Eagleworks does not have any such T-Junction between the NASA truncated cone and a waveguide.
If I am incorrect, I would appreciate being corrected.
If I am correct, I don't understand the rationale that would support travelling waves in a completely enclosed truncated cone, as a travelling wave will not satisfy the boundary conditions necessary to solve Maxwell's equations for the tests performed by NASA Eagleworks.
The issue of power dissipation due to the skin effect is fully addressed in the COMSOL Fnite Element analyses, which predicted the measured Q's. The COMSOL Finite Element analysis fully respects conservation of momentum and conservation of energy.(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828276;image)In your image, you have a T-Junction from a waveguide into the EM Drive truncated cone.
Although Prof. Yang used such construction (for at least part of her tests), to my knowledge, NASA Eagleworks does not have any such T-Junction between the NASA truncated cone and a waveguide.
If I am incorrect, I would appreciate being corrected.
If I am correct, I don't understand the rationale that would support travelling waves in a completely enclosed truncated cone, as a travelling wave will not satisfy the boundary conditions necessary to solve Maxwell's equations for the tests performed by NASA Eagleworks.
Dosn't a standing wave assume 100% power reflection? Such as a powerline with no one consuming power. I thought the moving magnetic field modes were a symbol or illustration of power transport to a location (thermal loss). Maybe I am mistaken?
...I would not bet on that. The uncivil level of attack displayed by several new posters in this thread during the last few days has been such that I would not be surprised if Star-Drive decides not to post any further Eagleworks test information here. These uncivil attacks are launched by anonymous posters that hide behind monickers without ever revealing their real names. I very much doubt that these uncivil posters would dare to express themselves this way, face-to-face in a public presentation, as in an AIAA meeting, for example. I very much doubt that they would express themselves that way in writing if they would do it under their real name. It is certainly conduct never seen at professional meetings or in academia.
I'm hopeful we can get Mr. Shawyer to participate here IF folks are civil.
I must say I'm rather perplexed and puzzled by the sudden hostility that some of the newer participants demonstrate...
There is absolutely nothing wrong with being skeptic but i thought that curiosity was one of the key characteristics of being a scientist/researcher/engineer.
There is no better way to make progress then to have a thesis and antithesis collide in a civil manner.
I really do not understand what can be obtained or achieved by aggressively attacking people or their ideas. If you aim to disprove a theory then all you need to do is mass enough evidence that their theory is flawed.
Personally I find it still too early trying to come up with theories until the effect has been validated or not.
For me the most compelling evidence so far is still the 2007 rotating Demonstrator video by R Shawyer.
All we can do now is wait for Eagleworks to duplicate that test (and improve on some of the possible setup flaws, like hot jet exhaust nullification).
If the test fails, then the credibility of the device will get a serious hit...
If the test succeeds, it will most likely be a turning point in the research (and funding) of the EM drive.
So, instead of shooting lead at each other, why don't we just all relax and be supportive to the Eagleworks team so they can finalize that crucial test by July?
Pro or contra, you'll have your answer by July...
That said, it was to foresee that giving more publicity to the research through the NASA publication article, would attract some of the most aggressive opinionated people inhere.
On the positive side however, it also attracted some very much needed new participants that have clearly high level qualifications... (be them pro or contra, it doesn't matter)
I suppose it is up to the mods to weed out the offensive ones...
As for mr Shawyer, i think it is already obvious that he will not engage into the discussion here, partially because of the engagements he already has with other parties, as he explained in that private conversation, partially because he had his share of abusive language in the past....
....eagerly anticipating the next , high power test from Eagleworks... 8)
The problem is I predict that Eagleworks will succeed and still nobody will be impressed. Remember cold fusion? Excess heat beyond chemistry... replicated... 10x energy input... 100x energy input... the thing produced so much heat that it melted down in the middle of the night.. heat in palladium... nickle... thin films... neutrons... maybe it isn't fusion but something else... zero point energy...
Yet year after year nobody was producing a commercial product, viable theory or convincing demo. For some the only explanation was a conspiracy. Anyone remember the "hot fusion (sorry, need to stop here for a second and just say that I have to use stupid words to get my point across. I know that means I must have a weak argument, but that's why I use bad words)." preventing research into cold fusion in order to protect their programs? I bet Jed Rothwell is still chasing cold fusion. I do know that ICCF-19 was held last month.
Emdrive has all the same properties. An extraordinary claim much more so than cold fusion in fact. A theory that makes no sense. People making up new theories to fit bad experiments. Other people day dreaming about how we can build a real spaceship now. Arguments over how to obtain funding. Free bubble up and rainbow stew.
I'm sorry. I don't mean to be rude, unpleasant or confrontational but sometimes reality is unpleasant. In time most will give up on the EMdrive. Some will stay and probably drift into conspiracy theories. A trickle of new results will continue to excite a younger crowd. As a result the EM drive will never succeed and never ever ever go away.
Talk to me in ten years and see if I'm not right. I hope I'm wrong.
QuoteShawyer developed a theory and built a device to test it. If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. If he cannot see and address the violation of Galilean relativity then I wouldn't trust him to test a light bulb.This is wrong in so many different ways I don't know where to start...
I was surprised to see that the experiment results have not confirmed a null result yet. While I hope they do turn up a useful propulsion system, my money is still on a null result.
While this thread seems to have produced useful discussion, it seems that it is still being cluttered with references to Shawyer's theory. I have a physics background up through intermediate quantum mechanics, with just a touch of particle physics. I would like to answer some of the questions regarding Shawyer's theory so the discussion can move on to theories that are at least plausible such as the White's QV model.QuoteShawyer developed a theory and built a device to test it. If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. If he cannot see and address the violation of Galilean relativity then I wouldn't trust him to test a light bulb.This is wrong in so many different ways I don't know where to start...
By "this is wrong" are you referring to the emdrive theory paper by Shawyer? A partial list of things he demonstrates he does not understand in that paper include:
-the principle of relativity (the foundation of special relativity)
-how to apply velocity transforms in special relativity
-how to do a force balance (he ignores the slanted walls)
-the definition of an open vs closed system
I don't see how a person who fails at basic physics in this way could actually design an accurate experiment or correctly calculate the resulting forces.
Note that ppnl's post used the word "nonsense" not "wrong". Plenty of respectable physicists come up with wrong theories. In this case the theory is complete nonsense and demonstrates a lack of understanding*. In this case the experiment results cannot be trusted, hence the other labs attempting to replicate the results.
If anyone needs clarification on what exactly is wrong with Shawyer's paper, let me know, so we can get this out of the way.
*A less charitable assumption would be that this is deliberate, but "Never ascribe to malice that which is adequately explained by incompetence."
By "this is wrong" are you referring to the emdrive theory paper by Shawyer?No. I am referring to the complete lack of understanding of the scientific principle by ppnl.
Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.Quoteso in effect 0.
So nonzero? Say outside the bandwidth of a very narrow bandwidth cavity?
Ok guys, so a lot of new people into this thread, but this thread is mainly for the development of the EM Drive. We knew this would happen, so we have a new "Entry Level" thread for opening questions and general questions.
I've moved the last few pages of new members asking questions into that thread, so if you posted here and can't see it, don't worry, it's in this thread.
http://forum.nasaspaceflight.com/index.php?topic=37438.0
Posting this notice as some sites are linking to this thread and not the section or the article, so people are thinking this is the only thread on this.
Remember to use the above link and allow this thread to continue with the Eaglework folk and others updating progress.
I was surprised to see that the experiment results have not confirmed a null result yet. While I hope they do turn up a useful propulsion system, my money is still on a null result.It would seem Yang Juan uses a very similar explanation in her recent EM Drive paper. In case you have not had an opportunity to read it, here is the link: http://www.emdrive.com/yang-juan-paper-2012.pdf
While this thread seems to have produced useful discussion, it seems that it is still being cluttered with references to Shawyer's theory. I have a physics background up through intermediate quantum mechanics, with just a touch of particle physics. I would like to answer some of the questions regarding Shawyer's theory so the discussion can move on to theories that are at least plausible such as the White's QV model.QuoteShawyer developed a theory and built a device to test it. If his theory is nonsense then the first conclusion we should reach is that his test results are nonsense. Either that or he is the luckiest person in the world. If he cannot see and address the violation of Galilean relativity then I wouldn't trust him to test a light bulb.This is wrong in so many different ways I don't know where to start...
By "this is wrong" are you referring to the emdrive theory paper by Shawyer? A partial list of things he demonstrates he does not understand in that paper include:
-the principle of relativity (the foundation of special relativity)
-how to apply velocity transforms in special relativity
-how to do a force balance (he ignores the slanted walls)
-the definition of an open vs closed system
I don't see how a person who fails at basic physics in this way could actually design an accurate experiment or correctly calculate the resulting forces.
Note that ppnl's post used the word "nonsense" not "wrong". Plenty of respectable physicists come up with wrong theories. In this case the theory is complete nonsense and demonstrates a lack of understanding*. In this case the experiment results cannot be trusted, hence the other labs attempting to replicate the results.
If anyone needs clarification on what exactly is wrong with Shawyer's paper, let me know, so we can get this out of the way.
*A less charitable assumption would be that this is deliberate, but "Never ascribe to malice that which is adequately explained by incompetence."
I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
There's other perfectly sane ways of interacting with the QV which have been posted literally a thousand times in THIS forum over and over again since October.
I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
I also proposed EW to test either the SPR Demonstrator device or the SPR Flight Thruster (which Boeing should have sitting on a shelf) which it seems is considered a "High Fidelity Test Article"I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
I also proposed EW to test either the SPF Demonstrator device or the SPF Flight Thruster (which Boeing should have sitting on a shelf) which it seems is considered a "High Fidelity Test Article"I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
This belongs to Boeing: http://www.emdrive.com/flightprogramme.htmlI really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
Is that device someone up thread said belongs to Boeing now?
Would seem to me that if the thrust produced is horizontally, gravity can't have effect on it, besides bending it a teeny weeny bit. Time dilation at beginning and endpoint are same (same distance from gravity well), so in effect 0.Never really thought about this before, but is light in a cavity resonator gravitationally redshifted?Do you mean natural (i.e. earth) or artificial gravity that could be generated by space-time warping or other quantum voodoo?
http://en.wikipedia.org/wiki/Gravitational_redshift
I mean, if you had an Emdrive sitting the table (large diameter down) here on Earth, and it was energized by feeding RF into a slot/probe located at the large diameter. Would an observer at the small end notice a red shift?
Vertically you could measure it, but the redshift from earth's gravity is already extremely difficult to measure, but if you could you could then detract that from the redshift value measured in the cavity.Quoteso in effect 0.
So nonzero? Say outside the bandwidth of a very narrow bandwidth cavity?
For weak gravitational field the frequency ratio between top and bottom is ft/fb = (1 + Rs/2rt - Rs/2rb) where Rs is Schwarzschild radius, rt and rb distance from centre of body (earth centre). From there (http://fr.wikipedia.org/wiki/D%C3%A9calage_d%27Einstein#Fr.C3.A9quence_propre_et_fr.C3.A9quence_observ.C3.A9e), sorry this is French wikipedia, I don't find a convenient English resource for the same formula.
For Earth Rs is about 9mm (http://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters), so lets say we have 0.3m altitude difference at earth surface (6.371e6m) => ft/fb = 1 - 3.3e-17
This is one part in 3e16 redshift in frequency.
Likewise any Doppler effect affecting the relative wavelengths (momentums) of photons between forward and backward plates of an accelerating frustum would indeed induce a non 0 net force : this force would always be opposite to the acceleration (ie. never a thrust) and in fact could be interpreted as the inertia of the mass equivalent of energy bouncing back and forth in the cavity (whatever its shape). The time constant of a photon in a Q=10000 about 0.3m across frustum would be like 10µs, at 100W pumped into the frustum there is then on the order of 1e-3 J EM energy content at any given time, that is equivalent to 1.1e-20 kg of mass, or an apparent added "force of inertia" of 1.1e-19N for a spacecraft accelerating at 1g, or equivalently an added weight of 1.1e-19N vertically for a resting frustum on earth.
In summary, within classical frameworks, yes there can be non 0 net force of EM radiation in an accelerating cavity, but this will be vanishingly small forces, and always opposite to acceleration (aka "inertia").
Is it correct ?
Well was not that dark as EW displayed the attached.I also proposed EW to test either the SPF Demonstrator device or the SPF Flight Thruster (which Boeing should have sitting on a shelf) which it seems is considered a "High Fidelity Test Article"I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
Good luck with that being as from what was posted up thread it has been implied that's gone dark as they say.
I also proposed EW to test either the SPF Demonstrator device or the SPF Flight Thruster (which Boeing should have sitting on a shelf) which it seems is considered a "High Fidelity Test Article"I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
This belongs to Boeing: http://www.emdrive.com/flightprogramme.html
And maybe this as Boeign bought all the SPR EM Drive IP in 2010: http://emdrive.com/demonstratorengine.html
Agree building your own device is good. So is validation of Shawyer EM Drive thrust. Established a base line. Establishes once and forever that it works as claimed. Then start to work out why.I also proposed EW to test either the SPF Demonstrator device or the SPF Flight Thruster (which Boeing should have sitting on a shelf) which it seems is considered a "High Fidelity Test Article"I really like the Shawyer Demonstrator device (attached). As an engineer I can appreciate designing, building and testing it plus the hours and money involved. It is a serious and professionally built device. It is not a toy but a real working thruster that can be taken anywhere to have additional tests done.
Maybe if EW asked Shawyer nicely, they could test it? At least then they have an established test data base and working device to work from.
Why doesn't Sawyer just bring it to Glenn Research Center to test there? They already offered to test the device if it can produce more than 100 micro-newton, and Shawyer's device is purportedly well above that.
There are merits to rebuilding a device instead of simply retesting the same device.
By building a new device, according similar specs and testing it, you can actually validate the principle behind the 2 devices (Shawyer's and EW's) if they produce similar results.
If they contradict each other, you'll need additional testing, of course..
By simply retesting the Shawyer's device you could potentially duplicate the same flaw. Just the measurement setup would be different....
Great. So Boeing should have no issues sending the Demonstrator and Flight Thruster EM Drives over to EW to test?This belongs to Boeing: http://www.emdrive.com/flightprogramme.html
And maybe this as Boeign bought all the SPR EM Drive IP in 2010: http://emdrive.com/demonstratorengine.html
Boeing's Phantom Works, which has previously explored exotic forms of space propulsion, was said to be looking into it some years ago. Such work has evidently ceased. “Phantom Works is not working with Mr. Shawyer,” a Boeing representative says, adding that the company is no longer pursuing this avenue [as of Nov 5, 2012].
http://aviationweek.com/awin/propellentless-space-propulsion-research-continues
Well was not that dark as EW displayed the attached.
Lower right is the Flight Thruster Boeing acquired from SPF (Shawyers company). Note it is rated as a "High Fidelity Test Article". Guess that means it works well and is highly reliable in the test results generated.
By simply retesting the Shawyer's device you could potentially duplicate the same flaw. Just the measurement setup would be different....
The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
The issue of power dissipation due to the skin effect is fully addressed in the COMSOL Fnite Element analyses, which predicted the measured Q's. The COMSOL Finite Element analysis fully respects conservation of momentum and conservation of energy.(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828276;image)In your image, you have a T-Junction from a waveguide into the EM Drive truncated cone.
Although Prof. Yang used such construction (for at least part of her tests), to my knowledge, NASA Eagleworks does not have any such T-Junction between the NASA truncated cone and a waveguide.
If I am incorrect, I would appreciate being corrected.
If I am correct, I don't understand the rationale that would support travelling waves in a completely enclosed truncated cone, as a travelling wave will not satisfy the boundary conditions necessary to solve Maxwell's equations for the tests performed by NASA Eagleworks.
Dosn't a standing wave assume 100% power reflection? Such as a powerline with no one consuming power. I thought the moving magnetic field modes were a symbol or illustration of power transport to a location (thermal loss). Maybe I am mistaken?
There can only be travelling waves if there is a net momentum flux. But such momentum is prevented by the previous arguments based on conservation of momentum (unless suitable emission of particles can support the measured thrust).
Thermal losses in a vacuum (unless there is outgassing, etc.) cannot support the claimed thrust forces, due to the previously addressed issue (what particles are being emitted, and what is their momentum).
All the above is true under linear Maxwell's equations and special relativity. Otherwise one would have to argue for breaking of P T parity, nonlinear anisotropic effects, coupling interaction with outside fields, etc.
In his recent interview video Shawyer discusses the Boeing deal at 3:30, 1st video. http://www.emdrive.com/interview.htmlThe fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
Phantom Works often works on classified projects so that last conspiracy theory might not actually be too far fetched, especially considering how little they had to say about why they are no longer working with Shawyer. If anyone has contact with Shawyer, it might be interesting "experiment" to ask Shawyer how things are going with Phantom Works, to see if his response sounds suspiciously like someone who's been silenced under contract to not talk about it.
By simply retesting the Shawyer's device you could potentially duplicate the same flaw. Just the measurement setup would be different....
It's easier to reverse engineer a working alien technology if you have an example that you can perform experiments on, than it is to re-engineer that technology when it violates what you think you know about physics!
The eagleworks drive is orders of magnitude lower thrust and cannot even be independently validated due to the low thrust levels. We don't even know if eagleworks will be capable of producing a higher thrust version, because their plans are based on a hypothetical understanding of how it works which has been highly criticized.
We don't know if Shawyer's device actually produces the thrust levels that he claims. The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
{snip}
We don't know if Shawyer's device actually produces the thrust levels that he claims. The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
Even without conspiracy theories, that last line sounds very plausible to me. We all know Boeing is in bed with the U.S. government (OK one then :P)By simply retesting the Shawyer's device you could potentially duplicate the same flaw. Just the measurement setup would be different....
It's easier to reverse engineer a working alien technology if you have an example that you can perform experiments on, than it is to re-engineer that technology when it violates what you think you know about physics!
The eagleworks drive is orders of magnitude lower thrust and cannot even be independently validated due to the low thrust levels. We don't even know if eagleworks will be capable of producing a higher thrust version, because their plans are based on a hypothetical understanding of how it works which has been highly criticized.
We don't know if Shawyer's device actually produces the thrust levels that he claims. The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
If Boeing found the tech to be viable I don't think the rejection of federal budget would stop them pumping their own money into it. This may be tracable through bookkeeping records that are made public.{snip}
We don't know if Shawyer's device actually produces the thrust levels that he claims. The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
Or Boeing did not get a government grant to develop the thruster so they cancelled the project.
Shawyer made a public statement. Specifically about the EM Drive tech Boeing licensed. There is no speculation about what he said.By simply retesting the Shawyer's device you could potentially duplicate the same flaw. Just the measurement setup would be different....
It's easier to reverse engineer a working alien technology if you have an example that you can perform experiments on, than it is to re-engineer that technology when it violates what you think you know about physics!
The eagleworks drive is orders of magnitude lower thrust and cannot even be independently validated due to the low thrust levels. We don't even know if eagleworks will be capable of producing a higher thrust version, because their plans are based on a hypothetical understanding of how it works which has been highly criticized.
We don't know if Shawyer's device actually produces the thrust levels that he claims. The fact that Boeing purchased the technology, then decided not to pursue it, is evidence that after their independent testing of his device, they must have concluded it to be useless (although I suppose it is possible that they are lying, and that it was a strategic statement designed to make everyone think it was pseudo-science so that they could have more time to develop it in secret).
The moderators may have to start up a new thread devoted to em-drive conspiracy theories; or better yet just delete all such posts. :)
transcript from the video (timeframe 4:10):And yet EW or some other body labels the SPR Flight Thruster that Boeing licensed (lower right in attachment) a "High Fidelity Test Article". Don't think that label, on a NASA publication, came from SPR or Shawyer or would be put on a non functional device that did not produce reliable thrust.
"...in fact... we actually transfered all our design and test data to Boeing.
It is noticable that any subsequent programs have not been acknowledged in the public domain..."
It doesn't really say it has been terminated by Boeing, just that no info is being released from their side.
It could either mean it has gone "dark" (militarized), or that it is shelved (cancelled) or put on ice (on hold)... yours to pick..
The problem is I predict that Eagleworks will succeed and still nobody will be impressed. Remember cold fusion? Excess heat beyond chemistry... replicated... 10x energy input... 100x energy input... the thing produced so much heat that it melted down in the middle of the night.. heat in palladium... nickle... thin films... neutrons... maybe it isn't fusion but something else... zero point energy...
Yet year after year nobody was producing a commercial product, viable theory or convincing demo. For some the only explanation was a conspiracy. Anyone remember the "hot fusion (sorry, need to stop here for a second and just say that I have to use stupid words to get my point across. I know that means I must have a weak argument, but that's why I use bad words)." preventing research into cold fusion in order to protect their programs? I bet Jed Rothwell is still chasing cold fusion. I do know that ICCF-19 was held last month.
Emdrive has all the same properties. An extraordinary claim much more so than cold fusion in fact. A theory that makes no sense. People making up new theories to fit bad experiments. Other people day dreaming about how we can build a real spaceship now. Arguments over how to obtain funding. Free bubble up and rainbow stew.
I'm sorry. I don't mean to be rude, unpleasant or confrontational but sometimes reality is unpleasant. In time most will give up on the EMdrive. Some will stay and probably drift into conspiracy theories. A trickle of new results will continue to excite a younger crowd. As a result the EM drive will never succeed and never ever ever go away.
Talk to me in ten years and see if I'm not right. I hope I'm wrong.
@ppnl we're here to solve problems, not handwave and accept the world will never find a better way. If you don't have any solutions, you're in the wrong place.
I like the 'turntable test.' Seems like something the Eagleworks team should shoot for. But...does this system of measuring thrust have any flaws that might skew the results?
This belongs to Boeing: http://www.emdrive.com/flightprogramme.html
And maybe this as Boeign bought all the SPR EM Drive IP in 2010: http://emdrive.com/demonstratorengine.html
Boeing's Phantom Works, which has previously explored exotic forms of space propulsion, was said to be looking into it some years ago. Such work has evidently ceased. “Phantom Works is not working with Mr. Shawyer,” a Boeing representative says, adding that the company is no longer pursuing this avenue [as of Nov 5, 2012].
http://aviationweek.com/awin/propellentless-space-propulsion-research-continues
I like the 'turntable test.' Seems like something the Eagleworks team should shoot for. But...does this system of measuring thrust have any flaws that might skew the results?
Correct me if I'm wrong, but It appears to me that this apparatus is merely a measure of total displacement, not force, and it is only your assumption that the displacement is due to a consistent net force. Any unconstrained vibrating object restricted to planar motion is likely to form a random walk across the plane, but when you restrict the motion to 1 dimension (clockwise or counterclockwise), as was done in this turntable, then the displacement will monotonically go either clockwise or counterclockwise, because a complete reversal of direction would require overcoming the existing momentum. In other words, I think the motion in this video could be explained by mere vibrations that have no net force, with a direction of motion that is restricted by the conditions at initialization.
I apologize in advance my understanding is likely no where near where it should be but, there are no stupid questions only stupid people so prove me stupid.
Is it possible this device is condensing spacetime at one side and expanding it at the other creating a gravitational flow to one side?
This could explain some things like why when more power is put in the force becomes more directional or why the force changes depending on its orientation to the Earth's gravitational field.
Maybe somebody should place an atomic clock in the force it is producing.
Very interesting suggestion. But I would have expected random vibrations to produce random walk motion in one direction with a ratchet form of stick-slip friction or a bearing acting with a ratchet-like action, as found in molecular motors...
The ratchet-like action would explain why it wants to move in only one direction (a factor TheTraveller has pointed out). (Without the ratchet-like action, just with stick slip friction it would initially move in either direction, depending on initial conditions)
I didn't mean that an actual ratchet was used to conceal the motion of course, instead I meant that something in the system is naturally acting as a ratchet, that's why I gave the example with references about molecular motors whose motion work as a ratchet random walk.Very interesting suggestion. But I would have expected random vibrations to produce random walk motion in one direction with a ratchet form of stick-slip friction or a bearing acting with a ratchet-like action, as found in molecular motors...
The ratchet-like action would explain why it wants to move in only one direction (a factor TheTraveller has pointed out). (Without the ratchet-like action, just with stick slip friction it would initially move in either direction, depending on initial conditions)
The direction of motion could be controlled with a ratchet, but that would be pretty difficult to conceal and so would be an unlikely way to cheat.
More likely would be to have a very slight inclination, or to set it up so there is slightly more friction on one side than the other, thus controlling the initial otherwise random direction of movement.
One would have to examine the system, for anything that unintentionally acts like a ratchet.
One would have to examine the system, for anything that unintentionally acts like a ratchet.
Interesting. However, this would only be necessary in order to figure out exactly what was going on, if other methods of measuring the force were negative.
The real test that should be done is measuring the force using different methods, because if the experiment is somehow interacting with one type of measurement apparatus, it is unlikely to be interacting with others. If the force is real, then any method of measuring the force should produce the same result.
Perhaps we have been thinking about this problem the wrong way, trying to think of ways that a force would be generated, rather than trying to think of ways that the measurement apparatus used by EW might possibly be biased by the experiment.
The real test that should be done is measuring the force using different methods, because if the experiment is somehow interacting with one type of measurement apparatus, it is unlikely to be interacting with others. If the force is real, then any method of measuring the force should produce the same result.
I posted yesterday in this thread http://forum.nasaspaceflight.com/index.php?topic=37438.300 (http://forum.nasaspaceflight.com/index.php?topic=37438.300) hoping to get a reply to a question on if this device producing gravity I realize now the question I posted was vague and the way I comprised the post might look childish so I'll try to expand on it.
The original post was as follows.QuoteI apologize in advance my understanding is likely no where near where it should be but, there are no stupid questions only stupid people so prove me stupid.
Is it possible this device is condensing spacetime at one side and expanding it at the other creating a gravitational flow to one side?
This could explain some things like why when more power is put in the force becomes more directional or why the force changes depending on its orientation to the Earth's gravitational field.
Maybe somebody should place an atomic clock in the force it is producing.
I would like to correct a mistake in my original question before I start. When I said expanding spacetime at one side that is wrong it would simply be less compressed than the other side.
As I said in my original post my understanding of physics is not where it should be so it should be easy to prove this wrong for most of you and if you take 5 minutes to do so I will be extremely grateful.
I'll explain how I think this might be happening. If there is a denser concentration of microwaves in one side of the chamber compared to the other and these groups of microwaves are manipulating spacetime it would create a gravitational flow.
Basically I'm asking if it's possible this device is producing force by passing gravitons between groups of microwaves?
Yes I realize this probably sounds like crazy pseudo-science so I apologize in advance if you think this wasted your time.
It is very sad when people come to a forum hiding under monickers behaving in an abusive way which they would never dare do face to face or using their real names, and prevent communication with researchers, oh well
I posted yesterday in this thread http://forum.nasaspaceflight.com/index.php?topic=37438.300 (http://forum.nasaspaceflight.com/index.php?topic=37438.300) hoping to get a reply to a question on if this device producing gravity I realize now the question I posted was vague and the way I comprised the post might look childish so I'll try to expand on it.
The original post was as follows.QuoteI apologize in advance my understanding is likely no where near where it should be but, there are no stupid questions only stupid people so prove me stupid.
Is it possible this device is condensing spacetime at one side and expanding it at the other creating a gravitational flow to one side?
This could explain some things like why when more power is put in the force becomes more directional or why the force changes depending on its orientation to the Earth's gravitational field.
Maybe somebody should place an atomic clock in the force it is producing.
I would like to correct a mistake in my original question before I start. When I said expanding spacetime at one side that is wrong it would simply be less compressed than the other side.
As I said in my original post my understanding of physics is not where it should be so it should be easy to prove this wrong for most of you and if you take 5 minutes to do so I will be extremely grateful.
I'll explain how I think this might be happening. If there is a denser concentration of microwaves in one side of the chamber compared to the other and these groups of microwaves are manipulating spacetime it would create a gravitational flow.
Basically I'm asking if it's possible this device is producing force by passing gravitons between groups of microwaves?
Yes I realize this probably sounds like crazy pseudo-science so I apologize in advance if you think this wasted your time.
Simply put, photons carry the electromagnetic force of which microwaves are a part of. Photons have no mass therefor do not manipulate spacetime, only travel through it. The term "denser" can not apply to a massless particle.
The theoretical graviton is similar to the photon in that it is massless and it carries the gravitational force. Any mechanism for the absorption or emission of gravitons hasn't made much sense.
If this interests you, may i suggest "The Theory of Almost Everything" by Robert Derter. It will introduce you to some basic principles you will need to know.
Everyone knew nothing before they knew something!
I think it is simply important to have a space that is separated, where those who choose to entertain the idea can do so without continuous distraction from those who want to vent their frustration.Yes and the moderators have made some attempts.
I just wish we could remain on topic and talk about Emdrive experimental results, instead of the umpteenth attempt of refutation from new comers, that add nothing to the same umpteenth+1 reasons already brought and discussed here.
I'm not hostile to criticism, but the arguments of violation of conservation momentum, conservation of energy and relativity are well known. Just read the thread history people.
"High Fidelity Test Article" is just a name/label... Copied from Shawyer's literature.Interesting.
It could have been named "1000N/kW Test Article"
Would that have made any difference without independent testing?
It's useful to point out things that might create the appearance of thrust and to suggest a way to control for those things. It's not helpful to say that it can't work so stop experimenting.
I posted yesterday in this thread http://forum.nasaspaceflight.com/index.php?topic=37438.300 (http://forum.nasaspaceflight.com/index.php?topic=37438.300) hoping to get a reply to a question on if this device producing gravity I realize now the question I posted was vague and the way I comprised the post might look childish so I'll try to expand on it.
The original post was as follows.QuoteI apologize in advance my understanding is likely no where near where it should be but, there are no stupid questions only stupid people so prove me stupid.
Is it possible this device is condensing spacetime at one side and expanding it at the other creating a gravitational flow to one side?
This could explain some things like why when more power is put in the force becomes more directional or why the force changes depending on its orientation to the Earth's gravitational field.
Maybe somebody should place an atomic clock in the force it is producing.
I would like to correct a mistake in my original question before I start. When I said expanding spacetime at one side that is wrong it would simply be less compressed than the other side.
As I said in my original post my understanding of physics is not where it should be so it should be easy to prove this wrong for most of you and if you take 5 minutes to do so I will be extremely grateful.
I'll explain how I think this might be happening. If there is a denser concentration of microwaves in one side of the chamber compared to the other and these groups of microwaves are manipulating spacetime it would create a gravitational flow.
Basically I'm asking if it's possible this device is producing force by passing gravitons between groups of microwaves?
Yes I realize this probably sounds like crazy pseudo-science so I apologize in advance if you think this wasted your time.
Simply put, photons carry the electromagnetic force of which microwaves are a part of. Photons have no mass therefor do not manipulate spacetime, only travel through it. The term "denser" can not apply to a massless particle.
The theoretical graviton is similar to the photon in that it is massless and it carries the gravitational force. Any mechanism for the absorption or emission of gravitons hasn't made much sense.
If this interests you, may i suggest "The Theory of Almost Everything" by Robert Derter. It will introduce you to some basic principles you will need to know.
Everyone knew nothing before they knew something!
Confined photons in particular do have an energy density and affect spacetime as does any other (ie the cavity when filled w/ photons is heavier than when empty)
I just wish we could remain on topic and talk about Emdrive experimental results, instead of the umpteenth attempt of refutation from new comers, that add nothing to the same umpteenth+1 reasons already brought and discussed here.Sounds good to me.
I'm not hostile to criticism, but the arguments of violation of conservation momentum, conservation of energy and relativity are well known. Just read the thread history people.
Shawyer has also made it clear there is no need to put a dielectric inside the cavity & stated that doing so will reduce cavity Q (which will reduce thrust) and increase losses.
Seems to me that if anyone wishes to test an EM Drive, they should follow what Shawyer has said in what to avoid inside the cavity and how to put the drive into either Motor mode or Generator mode.
{snipped to keep the focus on my target}
His testing instructions are very clear.
http://www.emdrive.com/EmDriveForceMeasurement.pdf
{snipped to keep focus on my target}
This seems clear from my reading of the data & emails Shawyer has provided.
I just wish we could remain on topic and talk about Emdrive experimental results, instead of the umpteenth attempt of refutation from new comers, that add nothing to the same umpteenth+1 reasons already brought and discussed here.
I'm not hostile to criticism, but the arguments of violation of conservation momentum, conservation of energy and relativity are well known. Just read the thread history people.
Yes there is a Rachet mode but internal to the EM Drive. As Shawyer has explained, a EM Drive will not of itself move. It needs an unbalancing of the cavity forces. Push it one way and it resists as if it had infinite mass. Push it the other way and it moves as if it had no mass. This action forms a natural ratchet.I didn't mean that an actual ratchet was used to conceal the motion of course, instead I meant that something in the system is naturally acting as a ratchet, that's why I gave the example with references about molecular motors whose motion work as a ratchet random walk.Very interesting suggestion. But I would have expected random vibrations to produce random walk motion in one direction with a ratchet form of stick-slip friction or a bearing acting with a ratchet-like action, as found in molecular motors...
The ratchet-like action would explain why it wants to move in only one direction (a factor TheTraveller has pointed out). (Without the ratchet-like action, just with stick slip friction it would initially move in either direction, depending on initial conditions)
The direction of motion could be controlled with a ratchet, but that would be pretty difficult to conceal and so would be an unlikely way to cheat.
More likely would be to have a very slight inclination, or to set it up so there is slightly more friction on one side than the other, thus controlling the initial otherwise random direction of movement.
https://www.youtube.com/watch?v=FsJJrP7hBoA
https://www.youtube.com/watch?v=-7AQVbrmzFw
The references I gave in my prior post actually deal with random walks that have a preferred direction, called in academia ratchet motion.
A biased random walk is another type of possible random walk. But due to biased stick-slip it would be a ratchet random walk.
One would have to examine the system, for anything that unintentionally acts like a ratchet.
just a few examples of a ratchet mechanism due to stick slip friction:
https://www.youtube.com/watch?v=JWLXmY0QzP8
https://www.youtube.com/watch?v=aCN-HEBsdYM
https://www.youtube.com/watch?v=78l17ntJeqo
It would seem Yang Juan uses a very similar explanation in her recent EM Drive paper. In case you have not had an opportunity to read it, here is the link: http://www.emdrive.com/yang-juan-paper-2012.pdf
Based on the installation orientation of Figure 2, when the thruster is working normally, if the electromagnetic coil 3 is working, the net thrust is from the microwave resonator large end to the small end; if the electromagnetic coil 4 is working, the net thrust is from the microwave resonator small end to the large end.
if what you say is true there is no way Boeing or anyone else involved with any form of propulsion but especially aviation or space flight would lose interest. any reduced mass is astoundingly useful. Even if the thing only reduced mass by 1 percent it would revolutionize everything. Nothing would ever be the same again. Automobiles, trains, planes, rockets; everything.Is not what I say. Is what Shawyer explains in his how to measure the forces pdf and in his explanation of how his space plane would do a 0.05g vertical lift.
Simply put, photons carry the electromagnetic force of which microwaves are a part of. Photons have no mass therefor do not manipulate spacetime, only travel through it. The term "denser" can not apply to a massless particle.
The theoretical graviton is similar to the photon in that it is massless and it carries the gravitational force. Any mechanism for the absorption or emission of gravitons hasn't made much sense.
If this interests you, may i suggest "The Theory of Almost Everything" by Robert Derter. It will introduce you to some basic principles you will need to know.
Everyone knew nothing before they knew something!
if what you say is true there is no way Boeing or anyone else involved with any form of propulsion but especially aviation or space flight would lose interest. any reduced mass is astoundingly useful. Even if the thing only reduced mass by 1 percent it would revolutionize everything. Nothing would ever be the same again. Automobiles, trains, planes, rockets; everything.Is not what I say. Is what Shawyer explains in his how to measure the forces pdf and in his explanation of how his space plane would do a 0.05g vertical lift.
As another example of EM Drive ratchet mode operation, assume we had a EM Drive with a motor & generator mode maximum force generation of 9.8 Newtons and the device had a mass of 0.5kg.
Now support it 1 mtr off the ground via say a small pedestal table, oriented such that the force of gravity would put the EM Drive into Generator / force resistance mode.
Next switch it on.
Now remove the pedestal support table.
Observe it is hovering as the downward 0.5kg weight is opposed by generator mode, which has a max ability to resist 9.8 Newtons of force or 1kg of mass at the Earth's surface.
...
I trust this shows how the EM Drive is unlike anything humanity has experienced before. So please do not move forward thinking it is like a propellantless Hall thruster or rocket motor that generates thrust when the cavity is filled with microwave energy.
Your example is interesting.if what you say is true there is no way Boeing or anyone else involved with any form of propulsion but especially aviation or space flight would lose interest. any reduced mass is astoundingly useful. Even if the thing only reduced mass by 1 percent it would revolutionize everything. Nothing would ever be the same again. Automobiles, trains, planes, rockets; everything.Is not what I say. Is what Shawyer explains in his how to measure the forces pdf and in his explanation of how his space plane would do a 0.05g vertical lift.
As another example of EM Drive ratchet mode operation, assume we had a EM Drive with a motor & generator mode maximum force generation of 9.8 Newtons and the device had a mass of 0.5kg.
Now support it 1 mtr off the ground via say a small pedestal table, oriented such that the force of gravity would put the EM Drive into Generator / force resistance mode.
Next switch it on.
Now remove the pedestal support table.
Observe it is hovering as the downward 0.5kg weight is opposed by generator mode, which has a max ability to resist 9.8 Newtons of force or 1kg of mass at the Earth's surface.
So if I read you well and equivalence principle holds, having a rocket in deep space accelerating, by conventional mean, at 1g, a floor that is orthogonal to this acceleration, a pedestal resting on this floor, a powered EM drive resting on this pedestal in same configuration, remove the pedestal and one will observe the EM drive hovering above that floor (that is still accelerating at 1g). Meaning we now have a powered EM drive not needing to be "pushed" to accelerate at 1g (there is no longer any interaction between rocket and device).
Stop the conventional thrust of the rocket : the rocket will stop accelerating and proceed as an inertial mass at constant velocity (relative to whatever inertial frame). Let the device escape from an open front bay : it will continue to accelerate at 1g since it was no longer interacting with the rocket when the change in acceleration of the rocket occurred (no interaction => whatever change in rocket trajectory ignored). We now have a "conventionally" accelerating (thrusting) EM drive needing no added force.
So why bother with a Hall thruster ? Just put behind a big dumb powder booster that makes your EM drive accelerate at 1g for a fraction of a second the time it takes for the EM drive to "record" that acceleration as a "starting point". BTW, same argument above could be made if acceleration was 0.5g instead of 1g : this means we now have to add a new intrinsic variable to a moving object. What physical mechanism explains this memory effect of "initial acceleration" into an ongoing acceleration of given magnitude ?Quote...
I trust this shows how the EM Drive is unlike anything humanity has experienced before. So please do not move forward thinking it is like a propellantless Hall thruster or rocket motor that generates thrust when the cavity is filled with microwave energy.
Don't underestimate the aptitude of intelligent people to integrate counter intuitive formal systems when they show internal consistency.
There's other perfectly sane ways of interacting with the QV which have been posted literally a thousand times in THIS forum over and over again since October.
I have been reading these threads quite diligently lately but I am not sure what you are referring to. A link would be appreciated!
Mr. Shawyer passed this along to share. See attachment. I didn't see it on his website. Maybe I missed it.Please thank Roger Shawyer for this information and thank you for sharing.
Looks like it goes along with the IAC-14 presentation here:
http://www.emdrive.com/iac2014presentation.pdf
The conference, page 133:
http://www.iafastro.org/wp-content/uploads/2014/09/IAC-2014-Final-Programme.pdf
He didn't give permission to share the email text this time. If he ever emails back, I'll ask for permission.
We're all very fortunate to have the inventor of EmDrive contributing to the discussion.
Mr. Shawyer passed this along to share. See attachment. I didn't see it on his website. Maybe I missed it.Please thank Roger Shawyer for this information and thank you for sharing.
Looks like it goes along with the IAC-14 presentation here:
http://www.emdrive.com/iac2014presentation.pdf
The conference, page 133:
http://www.iafastro.org/wp-content/uploads/2014/09/IAC-2014-Final-Programme.pdf
He didn't give permission to share the email text this time. If he ever emails back, I'll ask for permission.
We're all very fortunate to have the inventor of EmDrive contributing to the discussion.
Seems Shawyer has thrown down a gauntlet.
Let the games begin.
Concerning the phrase “Shawyer has thrown down a gauntlet” , my understanding is that it means to challenge or confront someone. Please explain further:
Who is being challenged by Shawyer?
What is the challenge?
I'm talking about signs of atomization on the *outside* surface of the frustum. Although it would probably be happening in the inside as well. The copper atoms would be the propellent. I'm not sure what the mechanism would be, but it's obviously more than a thermal effect, and the whole reversal in phase/thrust would be difficult to explain. It seems more simple than QV or relativity models, but it's still probably interesting physics.Following on what jknuble said about the multipactor-like effect as a possible cause of thrust. http://en.wikipedia.org/wiki/Multipactor_effect I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust.
For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.
I can think of 3 ways to debunk this. 1) perhaps that amount of particles going that fast would be noticeable with the naked eye, so this isn't really a valid explanation. 2) stick a detector behind the thruster (are they ionized?). 3) SEM of the surface compared to scraps from the same batch of copper not used in the thrustum.
Just how would we get a net-thrust from a closed cavity with atomization. Even if atoms are being ioniozed inside the cavity I don't see how that could result in a net thrust. Atomization results in immediate thrust but then that creates impact on the other side of the cavity canceling out the propulsion.
Last year's R. Shawyer's conference presentation slides had been already posted in this thread. I had not seen the final version of the presentation paper (the attachment in @Mulletron's post) but, although it is nice to have for reference, I did not see something there that we had not discussed or reviewed before (including the latest superconducting design by Shawyer which we have discussed multiple times), as well as his project studies for aerospace.Roger that.
That conference was 6 months ago.
There are several things that are NOT new, and that have been discussed for several months in these threads, for example:
* that R. Shawyer no longer uses any dielectric inserts in his EM Drive
* that the latest design of R. Shawyer is superconducting with Doppler compensation, and large cone angle and spherical ends
As an example of what can happen in 6 months of R&D, during the last 6 months, NASA Eagleworks reported:
1) The first time that any organization has conducted EM Drive tests in a vacuum
2) A positive signal in their interferometer tests, using an EM Drive pillbox shape as the test item.
QUESTIONS:
Is there any update on what is the progress with Shawyer's superconducting EM Drive?
Does he report an experimental Q?
Does he report any experimental measurements during the last 6 months?
Does anybody have an explanation why Shawyer reports measurements of force in opposing directions for the Demonstrator engine and ONLY for this engine (it cannot be a typo, since it is repeated in the final version of the conference paper).
If I have missed something new, that had not been reviewed previously, I would appreciate if somebody could point it out.
If there nothing new that can be pointed out, there is no need to reply.
Thanks.
Roger that.
Good to know all the data that can be mined from past presentations and postings has been mined, discussed, sorted and filed away. Guess we wait for new data from EW's test of their new build, which hopefully follows Shawyers test protocol and elimination of dielectrics recommendations, at least initially.
Wonderful breakthrough in many ways.Yes, it has been discussed earlier in these threads, and it would enable testing at NASA Glenn for example. NASA Eagleworks does not have the budget to do it.
I was wondering has anyone given the thought to putting several of the EM drives in series?
I know I'm new here but I've been in engineering for almost 50 years. The EM drive seems to parallel so many things I've seen in electronics and embrace harmonics and it got me thinking how it would compare to things like a YAGI antenna for gain buy linking them in series. Would you get a Q gain in thrust?
What I read is, the Chinese test rig has 2 coils, electromagnets, one of which is activated, once the test article moves from plum, to force the test article back to plum. Coils are calibrated as to the restorative force they generate per current input. Depending on which way the test article moves, either coil 3 or coil 4 is activated to restore the test article to plum and the current drawn determines the force generated by the test article.
Roger that.
Good to know all the data that can be mined from past presentations and postings has been mined, discussed, sorted and filed away. Guess we wait for new data from EW's test of their new build, which hopefully follows Shawyers test protocol and elimination of dielectrics recommendations, at least initially.
No, you have already shown that we need to revisit what Mr. Shawyer has been reporting. This forum has not given the necessary attention to most of it. Also look back up in the thread where @meberbs was talking about the Chinese using coils. I don't ever remember talking about that.
I about fainted when I read that because I'm convinced this thing works primarily off the magnetic field component inside the cavity.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1368813#msg1368813
I know from experiment that a magnetic field goes right though the thin copper from one side to the other. So that is trivial to pull off. Hopefully Eagleworks accounted for the magnetic field going the other way..inside to out.
@TheTraveller, keep bring in fresh insight. You're rocking this thread.
Hopefully Eagleworks accounted for the magnetic field going the other way..inside to out.
Lastly find attach a slide with the results of this week's test that demonstrate that the copper frustum still generates a thrust signature when it is not in the stainless steel vacuum chamber walls. And as you will note the forward thrust signature is similar in magnitude for the same 50W case in-air in the vacuum chamber, so I think we can start to put to bed the idea that standard E&M evanescent waves interactions with the vacuum chamber walls are the cause of these thrust signatures.
Further thoughts that I think correlate to the TheTraveller's statements.
I was thinking about my post from last night and was pondering why, if pushed in the "forward" direction the drive begins and continues to accelerate. If you imagine the drive creating two gravity wells, small/deep at rear and large/shallow at front. Once the drive is pushed, the gravity wells would follow the drive HOWEVER the reaction is subject to the speed of light. That momentary delay might allow for the drive to slip into the forward gravity well's wake and begin accelerating (essentially falling).
Just food for thought...
What I read is, the Chinese test rig has 2 coils, electromagnets, one of which is activated, once the test article moves from plum, to force the test article back to plum. Coils are calibrated as to the restorative force they generate per current input. Depending on which way the test article moves, either coil 3 or coil 4 is activated to restore the test article to plum and the current drawn determines the force generated by the test article.
Roger that.
Good to know all the data that can be mined from past presentations and postings has been mined, discussed, sorted and filed away. Guess we wait for new data from EW's test of their new build, which hopefully follows Shawyers test protocol and elimination of dielectrics recommendations, at least initially.
No, you have already shown that we need to revisit what Mr. Shawyer has been reporting. This forum has not given the necessary attention to most of it. Also look back up in the thread where @meberbs was talking about the Chinese using coils. I don't ever remember talking about that.
I about fainted when I read that because I'm convinced this thing works primarily off the magnetic field component inside the cavity.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1368813#msg1368813
I know from experiment that a magnetic field goes right though the thin copper from one side to the other. So that is trivial to pull off. Hopefully Eagleworks accounted for the magnetic field going the other way..inside to out.
@TheTraveller, keep bring in fresh insight. You're rocking this thread.
Chinese thrust measurement system attached.
But this is NOT what was measured at NASA Eagleworks. Nothing needed to be pushed and nothing was pushed at NASA Eagleworks.Further thoughts that I think correlate to the TheTraveller's statements.
I was thinking about my post from last night and was pondering why, if pushed in the "forward" direction the drive begins and continues to accelerate. If you imagine the drive creating two gravity wells, small/deep at rear and large/shallow at front. Once the drive is pushed, the gravity wells would follow the drive HOWEVER the reaction is subject to the speed of light. That momentary delay might allow for the drive to slip into the forward gravity well's wake and begin accelerating (essentially falling).
Just food for thought...
Or something much more mundane:
http://usersguidetotheuniverse.com/?p=2865
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
That sounds exactly like ME too. Same freaking thing. Two sides of the same coin.
ME=Classical description
EM=Quantum description
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
(http://usersguidetotheuniverse.com/wp-content/uploads/2013/03/box_photons_moving.png)
Or something much more mundane:
http://usersguidetotheuniverse.com/?p=2865
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
That sounds exactly like ME too. Same freaking thing. Two sides of the same coin.
ME=Classical description
EM=Quantum description
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
(http://usersguidetotheuniverse.com/wp-content/uploads/2013/03/box_photons_moving.png)
But this is NOT what was measured at NASA Eagleworks. Nothing needed to be pushed and nothing was pushed at NASA Eagleworks.
Now, two different experiments and mechanisms are being discussed (#2 as treated by Mulletron and TheTraveller):
1) NASA Eagleworks. Stationary test item. Thrust force in same direction as movement.
2) SHAWYER. Need moving item to measure force ?. Thrust force in opposite direction to movement. (All kind of experimental issues here, and a lack of experimental force-vs.-time data to analyze).
Since they are different, I wonder whether we should split threads into NASA Eagleworks and a separate thead for the others. This would prevent confusion.
We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
But this is NOT what was measured at NASA Eagleworks. Nothing needed to be pushed and nothing was pushed at NASA Eagleworks.
That (rotation of the Earth) does not make any difference regarding a change from initial conditions for an unrestrained drive. What Mulletron and TheTraveller are proposing is:QuoteBut this is NOT what was measured at NASA Eagleworks. Nothing needed to be pushed and nothing was pushed at NASA Eagleworks.
We are on a rotating sphere, could that be the push?
I think just recently (maybe within 15 to 20 pages ago someone said that Dr White considers the EM drive to be a case of warp drive because he thinks the underlying principles of operation are dipping into the same source. My memory is really vague but if I remember right you are not too far off the mark. at least on one branch of consideration here.
Or something much more mundane:
http://usersguidetotheuniverse.com/?p=2865
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
That sounds exactly like ME too. Same freaking thing. Two sides of the same coin.
ME=Classical description
EM=Quantum description
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
(http://usersguidetotheuniverse.com/wp-content/uploads/2013/03/box_photons_moving.png)
Going into the speculation side and maybe a silly error: this observation could also match with EW's potential observation of a warpdrive signature.
If I remember well, they have mentioned something called 'boost' that seems to be a speed multiplier.
What if we are actually seeing that, a initial speed from an imparted momentum, just slightly 'boosted'?
I think just recently (maybe within 15 05 20 pages ago Someone Said that Dr White considers the EM drive to be a case of warp drive because he thinks the underlying principles of operation are dipping into the same source. My memory is really vague but if I remember right you are not too far off the mark. at least on one branch of consideration here.
In order for an organization to be Operationally Disciplined (doing the right thing, the right way, every time to achieve Operational Excellence), it takes a commitment from all employees not only to themselves, but also to one another. The concept of Forceful Watch Team Backup is rooted in everyone’s understanding that they are part of something larger than themselves, everyone relies on one another and there is a level of seriousness to the jobs they do. With that as a foundation, employees are driven to back up one another to ensure that everyone is doing the right thing, the right way, every time. And if a fellow employee has overlooked something or is not behaving in an Operationally Disciplined manner, other employees have the courage to step in and help resolve the issue. Employees are actively looking for what might be wrong in each other’s areas and expect others to do the same in return. It is everyone’s responsibility to ensure the company succeeds-if one person fails, everyone fails.
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
...
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
If a cavity needs an impulse, how small would that impulse need to be to get things going? is there a threshold value beyond which a push will make a difference, or not? Maybe that could explain why it needs an impulse to start up, and that current theories pertaining random particle movement imply impulses that fall below the threshold value? Maybe someone can answer that question.My understanding, based on Shawyer data, is the EM Drive has 2 modes that will cause a external force, in opposite directions, to be generated. One he calls Motor mode and the other Generator mode.
Furthermore, If it needs a push to put things in motion, wouldn't that action create the needed reference frame to explain this the classical way? And that before the push(with the EM drive activated) a new explanation is needed? (saying it this way because i cannot describe it).
I am truly sorry if this has all been discussed/dismissed before. delete this post if necessary.
If a drive needs an impulse to get thrust production, how small would that impulse need to be to get things going? is there a threshold value beyond which a push will make a difference, or not? Maybe that could explain why it needs an impulse to start up, and that current theories pertaining random particle movement imply impulses that fall below the threshold value? Maybe someone can answer that question.
Furthermore, If it needs a push to put things in motion, wouldn't that action create the needed reference frame to explain this the classical way? And that before the push(with the EM drive activated) a new explanation is needed? (saying it this way because i cannot describe it).
Physical interaction may be a better term if that threshold value turns out to be 0.
I am truly sorry if this has all been discussed/dismissed before. delete this post if necessary.
How small a movement will it take for the resonate cavity energy waves to become unbalanced? 1um? Larger? Smaller? Function of wavelength versus phase distortion?If a drive needs an impulse to get thrust production, how small would that impulse need to be to get things going? is there a threshold value beyond which a push will make a difference, or not? Maybe that could explain why it needs an impulse to start up, and that current theories pertaining random particle movement imply impulses that fall below the threshold value? Maybe someone can answer that question.
Furthermore, If it needs a push to put things in motion, wouldn't that action create the needed reference frame to explain this the classical way? And that before the push(with the EM drive activated) a new explanation is needed? (saying it this way because i cannot describe it).
Physical interaction may be a better term if that threshold value turns out to be 0.
I am truly sorry if this has all been discussed/dismissed before. delete this post if necessary.
I fully agree with you. Neither the threshold impulse is defined, nor is it supported by anything. :)
If a cavity needs an impulse, how small would that impulse need to be to get things going? is there a threshold value beyond which a push will make a difference, or not? Maybe that could explain why it needs an impulse to start up, and that current theories pertaining random particle movement imply impulses that fall below the threshold value? Maybe someone can answer that question.My understanding, based on Shawyer data, is the EM Drive has 2 modes that will cause a external force, in opposite directions, to be generated. One he calls Motor mode and the other Generator mode.
Furthermore, If it needs a push to put things in motion, wouldn't that action create the needed reference frame to explain this the classical way? And that before the push(with the EM drive activated) a new explanation is needed? (saying it this way because i cannot describe it).
I am truly sorry if this has all been discussed/dismissed before. delete this post if necessary.
If you push against the EM Drive such that Generator mode is activated, it will resist your push and not move. If you push it in the other direction, Motor mode is activated and it will move away from your push.
I then see any random event causing Generator to be activated resulting in no backward movement, while random events which activate Motor mode will move the EM Drive forward with no applied external force. This may be a small effect and use of an long term external force may cause higher acceleration rates.
In Generator mode, the backward push kinetic energy is converted into higher cavity energy and finally heat and in Motor mode the forward push drains cavity energy and converts it into forward kinetic energy, while drawing replacement from the microwave generator, which draws energy from the primary energy supply. Thus vehicle gained kinetic energy is that drawn from the primary energy supply minus losses. COE conserved.
Shawyer proposed Generator could be used to decelerate the vehicle at no energy cost to the primary energy source. Could be used to stop additional acceleration as the vehicle enters a gravity well.
This is my opinion based on what I read from what Shawyer has stated. Time will tell if both, one or the other or neither are correct.
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
...
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
Trying to understand the implication here. If your frustum were mounted on a shaker table can you speculate the most interesting excitation frequencies? Keeping in mind your test setup would a sub-woofer be adequate?
A FAQ page would be super helpful and is sorely needed. But it won't make much difference if it isn't easily accessible. Ideally there'd be a link to it at the top of every page on this forum- or better yet, appended to every post that anybody makes.Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
Seriously thank you bro. That is some serious gettin' stuff done.
Chinese did report their cavity bandwidth data:
A resonant cavity can ONLY support certain frequencies. If those frequencies change, say due to red or blue shift, they won't/can't resonate, and are lost. That resonant cavity that was once saturated, now has a "hole" which can be filled by more incoming radiation, said another way energy flowing back in. The transient Poynting vector. In layman's terms.
The missing Poynting vector is due to us never considering an accelerating cavity. Shawyer says it has to move first before you observe a force. He isn't just saying that. He probably observed that.
...
See that bottom pic. Those "dips" are the only frequencies that will exist within that range of my cavity. If they get shifted up or down (like by if I pick up the cavity and shake the crap out of it), they're history.
Trying to understand the implication here. If your frustum were mounted on a shaker table can you speculate the most interesting excitation frequencies? Keeping in mind your test setup would a sub-woofer be adequate?
If it were on a shaker table, I wouldn't know what to expect. Guess that depends on how narrow the bandwidth of the cavity is. That is @Rodal quality math.
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
Would @Chris Bergin be willing to set up a private thread just for talking with Mr. Shawyer, undisturbed by outside agitators?
http://emdrive.com/
Contact [email protected]
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
Welcome to the site's forum. That is a very good idea (as we can't really do a wiki style page here).
Top work, good new member :)
Would @Chris Bergin be willing to set up a private thread just for talking with Mr. Shawyer, undisturbed by outside agitators?
http://emdrive.com/
Contact [email protected]
We could create a standalone Q&A thread, like this one?
http://forum.nasaspaceflight.com/index.php?topic=37295.0
(Notice the format is different to a normal thread).
A FAQ page would be super helpful and is sorely needed. But it won't make much difference if it isn't easily accessible. Ideally there'd be a link to it at the top of every page on this forum- or better yet, appended to every post that anybody makes.Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
Seriously thank you bro. That is some serious gettin' stuff done.
Would seem from Shawyers latest presentation, recently shared by Mulletron, that flat end plates are out and convex / concave end plates are the new standard to reduce cavity losses and boost cavity Q / thrust generation per kW of cavity stored microwave energy.
While Shawyer did share this cavity variation applied to a superconducting cavity, why it was used and what the curves are based on is new information. Would seem to make very good sense to incorporate it into non superconducting cavities.
Is it not new information from Shawyer?Would seem from Shawyers latest presentation, recently shared by Mulletron, that flat end plates are out and convex / concave end plates are the new standard to reduce cavity losses and boost cavity Q / thrust generation per kW of cavity stored microwave energy.
While Shawyer did share this cavity variation applied to a superconducting cavity, why it was used and what the curves are based on is new information. Would seem to make very good sense to incorporate it into non superconducting cavities.
NOT NEW information at all.
Discussed already much earlier in the thread. I pointed out the reason. Please take a look at the ends of the truncated cone in my exact solutions and also in Greg Egan's.
The reason for the spherical ends is because the standing waves in a truncated cone cavity are spherical waves (this is known since the 1930's as per Shelkunoff's analysis)
We are talking about the same presentation that Mullerton just received from Shawyer and posted a day ago? The attached information was known 6 months ago?Is it not new information from Shawyer?Would seem from Shawyers latest presentation, recently shared by Mulletron, that flat end plates are out and convex / concave end plates are the new standard to reduce cavity losses and boost cavity Q / thrust generation per kW of cavity stored microwave energy.
While Shawyer did share this cavity variation applied to a superconducting cavity, why it was used and what the curves are based on is new information. Would seem to make very good sense to incorporate it into non superconducting cavities.
NOT NEW information at all.
Discussed already much earlier in the thread. I pointed out the reason. Please take a look at the ends of the truncated cone in my exact solutions and also in Greg Egan's.
The reason for the spherical ends is because the standing waves in a truncated cone cavity are spherical waves (this is known since the 1930's as per Shelkunoff's analysis)
I plan to build and test a Shawyer EM Drive with his new convex / concave end plates. Will take my design lead 100% from Shawyer at 1st as he is the only source that has built multiple EM Drives, measured generated significant force / thrust and shared enough real / practical data to allow replication of his many years of blood, sweat and tears.
The theory talk here is good background but not focused enough to be something an engineer can use to built a successful working EM Drive, at least not in the 1st instance. I believe in not reinventing the wheel, until I have several working wheels to do further development from.
I also plan to duplicate Shawyers vertical force measurement system as used in his Flight Thruster qualification. To me that is a very KISS solution.
Would welcome any suggestions as I have read others here have started down this pathway.
No, the information you posted from Shawyer was not new information on this thread.
The information you posted on Shawyer's including Shawyer's presentation (which dates 6 months ago) has been discussed multiple times in this thread.
One of the discussions was with an European Architect/Designer. We also discussed paraboloid cavities, for example.
Link?...yes.
We are talking about the same presentation that Mullerton just received from Shawyer and posted a day ago? The attached information was known 6 months ago?
We are talking about the same presentation that Mullerton just received from Shawyer and posted a day ago? The attached information was known 6 months ago?Is it not new information from Shawyer?Would seem from Shawyers latest presentation, recently shared by Mulletron, that flat end plates are out and convex / concave end plates are the new standard to reduce cavity losses and boost cavity Q / thrust generation per kW of cavity stored microwave energy.
While Shawyer did share this cavity variation applied to a superconducting cavity, why it was used and what the curves are based on is new information. Would seem to make very good sense to incorporate it into non superconducting cavities.
NOT NEW information at all.
Discussed already much earlier in the thread. I pointed out the reason. Please take a look at the ends of the truncated cone in my exact solutions and also in Greg Egan's.
The reason for the spherical ends is because the standing waves in a truncated cone cavity are spherical waves (this is known since the 1930's as per Shelkunoff's analysis)
I plan to build and test a Shawyer EM Drive with his new convex / concave end plates. Will take my design lead 100% from Shawyer at 1st as he is the only source that has built multiple EM Drives, measured generated significant force / thrust and shared enough real / practical data to allow replication of his many years of blood, sweat and tears.
The theory talk here is good background but not focused enough to be something an engineer can use to built a successful working EM Drive, at least not in the 1st instance. I believe in not reinventing the wheel, until I have several working wheels to do further development from.
I also plan to duplicate Shawyers vertical force measurement system as used in his Flight Thruster qualification. To me that is a very KISS solution.
Would welcome any suggestions as I have read others here have started down this pathway.
No, the information you posted from Shawyer was not new information on this thread.
The information you posted on Shawyer's including Shawyer's presentation (which dates 6 months ago) has been discussed multiple times in this thread.
One of the discussions was with an European Architect/Designer. We also discussed paraboloid cavities, for example.
The cavity comprises a small convex end plate, a
truncated conical side wall section, and a large
convex end plate. The end plate Radii R1 and R2
are selected such that R2-R1 = L1 where L1 is the
length of the side wall. This geometry ensures that
the EM wavefront propagates between the end plates
with every point on the wavefront travelling along a
radius line of length L1, centred at point O. This
constant path length over the wavefront ensures that
phase distortion over the very large number of
reflections within a high Q cavity, is minimised, and
the value of Q that is achieved in practice
approaches the theoretical maximum. Note that this
configuration ensures that there is no orthogonal
component of the guide velocity reflected from the
side wall, thus ensuring a zero side wall force
component in the axial plane.
We are talking about the same presentation that Mullerton just received from Shawyer and posted a day ago? The attached information was known 6 months ago?Is it not new information from Shawyer?Would seem from Shawyers latest presentation, recently shared by Mulletron, that flat end plates are out and convex / concave end plates are the new standard to reduce cavity losses and boost cavity Q / thrust generation per kW of cavity stored microwave energy.
While Shawyer did share this cavity variation applied to a superconducting cavity, why it was used and what the curves are based on is new information. Would seem to make very good sense to incorporate it into non superconducting cavities.
NOT NEW information at all.
Discussed already much earlier in the thread. I pointed out the reason. Please take a look at the ends of the truncated cone in my exact solutions and also in Greg Egan's.
The reason for the spherical ends is because the standing waves in a truncated cone cavity are spherical waves (this is known since the 1930's as per Shelkunoff's analysis)
I plan to build and test a Shawyer EM Drive with his new convex / concave end plates. Will take my design lead 100% from Shawyer at 1st as he is the only source that has built multiple EM Drives, measured generated significant force / thrust and shared enough real / practical data to allow replication of his many years of blood, sweat and tears.
The theory talk here is good background but not focused enough to be something an engineer can use to built a successful working EM Drive, at least not in the 1st instance. I believe in not reinventing the wheel, until I have several working wheels to do further development from.
I also plan to duplicate Shawyers vertical force measurement system as used in his Flight Thruster qualification. To me that is a very KISS solution.
Would welcome any suggestions as I have read others here have started down this pathway.
No, the information you posted from Shawyer was not new information on this thread.
The information you posted on Shawyer's including Shawyer's presentation (which dates 6 months ago) has been discussed multiple times in this thread.
One of the discussions was with an European Architect/Designer. We also discussed paraboloid cavities, for example.
Never discussed before:QuoteThe cavity comprises a small convex end plate, a
truncated conical side wall section, and a large
convex end plate. The end plate Radii R1 and R2
are selected such that R2-R1 = L1 where L1 is the
length of the side wall. This geometry ensures that
the EM wavefront propagates between the end plates
with every point on the wavefront travelling along a
radius line of length L1, centred at point O. This
constant path length over the wavefront ensures that
phase distortion over the very large number of
reflections within a high Q cavity, is minimised, and
the value of Q that is achieved in practice
approaches the theoretical maximum. Note that this
configuration ensures that there is no orthogonal
component of the guide velocity reflected from the
side wall, thus ensuring a zero side wall force
component in the axial plane.
Source IAC-14 paper:
http://tinyurl.com/ofl4527
Chinese did report their cavity bandwidth data:
http://www.emdrive.com/yang-juan-paper-2012.pdf
Chinese did report their cavity bandwidth data:
http://www.emdrive.com/yang-juan-paper-2012.pdf
Interesting. Earlier in the first thread the discussion centered around cavity Q and the need for a high Q. This cavity only has a Q = 1531.
The Q's reported in the tables 1 and 2 of http://www.emdrive.com/NWPU2010paper.pdf and in the above quote are much higher than the calculated Q based on the bandwidth.
Chinese did report their cavity bandwidth data:
http://www.emdrive.com/yang-juan-paper-2012.pdf
Interesting. Earlier in the first thread the discussion centered around cavity Q and the need for a high Q. This cavity only has a Q = 1531.
The 2013 paper from NWPU: "It was found that the thruster
cavity made by copper and resonating on the equivalent TE011
mode has a quality factor 320400 and generates total net EM
thrust 411 mN for 1000 W 2.45 GHz incident microwave."
http://iopscience.iop.org/1674-1056/22/5/050301
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2, you loose 99% of the power.
Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.
If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.
I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;
As a waveguide, the group velocity is something like;
v_g = c x sqrt(1 - (c/2d*f)^2)
Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.
c/2d = fc, is the Low cut-off frequency of the waveguide.
The refractive index depends on the Low cut-off frequency as a function of the diameter,
K = 1/sqrt( 1 - (fc/f)^2)
For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.
There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.
Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.
Here is how it conserves momentum;
In the PV Model, momentum transforms as,
p => p*sqrt(K)
In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity.
However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.
The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.
That’s IMHO as an engineer of course. Any comments?
See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering
Todd D.
In what sense does this conserve momentum?
Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.
When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.
(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,
p => p*sqrt(K)
THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.
Regards,
Todd D.
What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?
Regards,
JR
Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;
p = h/lambda
wavelength depends on velocity, and v_g is a variable inside the frustum.
That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.
I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.
Todd D.
Would @Chris Bergin be willing to set up a private thread just for talking with Mr. Shawyer, undisturbed by outside agitators?
We could create a standalone Q&A thread, like this one?
http://forum.nasaspaceflight.com/index.php?topic=37295.0
(Notice the format is different to a normal thread).
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
I repost here this post which may be of interest to people here as well:So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2, you loose 99% of the power.
Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.
If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.
I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;
As a waveguide, the group velocity is something like;
v_g = c x sqrt(1 - (c/2d*f)^2)
Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.
c/2d = fc, is the Low cut-off frequency of the waveguide.
The refractive index depends on the Low cut-off frequency as a function of the diameter,
K = 1/sqrt( 1 - (fc/f)^2)
For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.
There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.
Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.
Here is how it conserves momentum;
In the PV Model, momentum transforms as,
p => p*sqrt(K)
In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity.
However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.
The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.
That’s IMHO as an engineer of course. Any comments?
See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering
Todd D.
In what sense does this conserve momentum?
Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.
When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.
(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,
p => p*sqrt(K)
THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.
Regards,
Todd D.
What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?
Regards,
JR
Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;
p = h/lambda
wavelength depends on velocity, and v_g is a variable inside the frustum.
That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.
I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.
Todd D.
....But a cylindrical cavity displays no attenuation and no focusing in the axial direction (unlike the truncated cone). The experimenters in the US, UK and China are using truncated cones.
We have designed a cylindrical cavity to simplify the problem. Solutions to resonant freq are much easier and more intuitive in a cylinder, and hitting resonance (when we adjust the dielectric) with a constant frequency (from a microwave oven magnetron) will be possible by adjusting the height of the cylinder. ....
....But a cylindrical cavity displays no attenuation and no focusing in the axial direction (unlike the truncated cone). The experimenters in the US, UK and China are using truncated cones.
We have designed a cylindrical cavity to simplify the problem. Solutions to resonant freq are much easier and more intuitive in a cylinder, and hitting resonance (when we adjust the dielectric) with a constant frequency (from a microwave oven magnetron) will be possible by adjusting the height of the cylinder. ....
If you obtain no net thrust for the cylindrical cavity, will that have been worth the effort you went through (instead of testing a truncated cone, preferably with the same geometry dimensions as NASA's or one of Shaywer's ? )
Concerning obtaining the frequency and mode shape, does your University give you access to a Finite Element analysis package like COMSOL, or ANSYS Multiphysics, etc. so that you could then obtain a numerical solution for any arbitrary geometry and inserted dielectric ?
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again. My previous attempt at KM (just a simple Google Doc, which was pretty bad didn't catch on so I deleted it:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
@Mulletron et al., I am happy to assist in this. I agree, this forum is excellent for reviewing the latest contributions by all the excellent minds here, but newer folks are finding it difficult to get a handle on how we got here over the past hundred pages. As a result some of the same questions are being re-asked repeatedly. Ideally it might become the FAQ section that was discussed previously (which @Rodal noted some valid concerns regarding). Worth a try, at least.
To this end, I have set up a MediaWiki server at http://emdrive.echothis.com and will start by the adding the relevant links in today. However, I'm just a (non-practicing) mechanical engineer, not a physicist so my role in this would be limited to setting up the organization and linking to the relevant content already posted by people far more knowledgeable than I. Anyone who has been tracking the forum and would like to join in this endeavor, welcome!
I would be most happy to join this effort!
Quite amusingly, I only ever look at updates on this thread during the week (worktime simulations are...boring) and this weekend I had decided that what seemed like the best thing I could do to help out the efforts here (since I'm not particularly knowledgeable with this sort of physics) would be to set up the wiki. When I showed up this morning I saw that I had a rather astounding 13+ pages of forum thread to catch up on! (Usually it seems to be about 4-5).
So when I read Mulletron's suggestion my thoughts were "Ah ha! I'm on the case! But I should finish catching up first." and then I saw you had started one up.
My provisional plan had been to slowly work through from page 1 again creating topics for things as they came up and beginning to organize them as the groupings became obvious.
A few groupings I had identified earlier:
Possible Error Sources of Thrust: Things like thermal buckling, atmospheric effects, etc would get pages of their own and this grouping would just allow for easy perusing of these topics. It might be wise to organize them into some sort of 'Busted', 'Under Investigation', 'Other' groupings. Of course new information can elevate one of the topics out of the busted area or descend it as necessary.
Current Theories: Relatively simple, listing out Shawyer's, White's, the Chinese Teams, Mulletron's, etc theories on what is going on.
Thrust Modes and Results: This one probably just ends up being a table of its own, but is probably particularly specific to the Eaglework's team.
Status of DIY Efforts: Lets Mulletron, Notsosureofit, DIYFan, and others that are replicating this provide easy to reference status updates and other things (future plans, etc).
What I was envisioning was to attempt to use the wiki-source system to provide pointers from information to the forum posts concerning them.
Thoughts?
....But a cylindrical cavity displays no attenuation and no focusing in the axial direction (unlike the truncated cone). The experimenters in the US, UK and China are using truncated cones.
We have designed a cylindrical cavity to simplify the problem. Solutions to resonant freq are much easier and more intuitive in a cylinder, and hitting resonance (when we adjust the dielectric) with a constant frequency (from a microwave oven magnetron) will be possible by adjusting the height of the cylinder. ....
If you obtain no net thrust for the cylindrical cavity, will that have been worth the effort you went through (instead of testing a truncated cone, preferably with the same geometry dimensions as NASA's or one of Shaywer's ? )
Concerning obtaining the frequency and mode shape, does your University give you access to a Finite Element analysis package like COMSOL, or ANSYS Multiphysics, etc. so that you could then obtain a numerical solution for any arbitrary geometry and inserted dielectric ?
Dr. Rodal:
I was under the impression that a symmetric shape should produce a net thrust, based on the null Cannae test article at EW. The only asymmetry there was the dielectric slug in the end, correct?
I don't believe we have access to COMSOL, but I will look into another method.
We have yet to purchase materials and may be able to test a truncated shape as well as a symmetric shape with the same copper tube and end plates.
Instead, I am focusing on the difference in parameters of each experiment--what does the thrust depend on? EW saw a clear dependence on a dielectric, but Shawyer, NWPU and Fetta observed high efficiencies without one. But why does Shawyer mention the "dielectric-filled section" in one of his papers and not reference it in later experiments? http://www.emdrive.com/theorypaper9-4.pdfEarly on Shawyer did use a dielectric but gave it up saying he found it reduced Q and increased losses. Mullerton shared this email he recently received from Shawyer where the non use of a dielectric is stated.
Has NWPU tried their magnetron cavity using a dielectric? I believe I read a comment referencing a 2014 paper by Yang but I have not been able to find it.
Did EW test without a dielectric in a vacuum?
Zellerium, I am uncertain about if your University allows for this sort of thing or not, but for the purposes of the nascent Wiki under development, would you be willing to provide (later once you have them) some Bills of Materials as well as instructions documenting how you assembled and set up your rig?
Anyway after some sleep and morning coffee, I can now answer your question.if what you say is true there is no way Boeing or anyone else involved with any form of propulsion but especially aviation or space flight would lose interest. any reduced mass is astoundingly useful. Even if the thing only reduced mass by 1 percent it would revolutionize everything. Nothing would ever be the same again. Automobiles, trains, planes, rockets; everything.Is not what I say. Is what Shawyer explains in his how to measure the forces pdf and in his explanation of how his space plane would do a 0.05g vertical lift.
As another example of EM Drive ratchet mode operation, assume we had a EM Drive with a motor & generator mode maximum force generation of 9.8 Newtons and the device had a mass of 0.5kg.
Now support it 1 mtr off the ground via say a small pedestal table, oriented such that the force of gravity would put the EM Drive into Generator / force resistance mode.
Next switch it on.
Now remove the pedestal support table.
Observe it is hovering as the downward 0.5kg weight is opposed by generator mode, which has a max ability to resist 9.8 Newtons of force or 1kg of mass at the Earth's surface.
So if I read you well and equivalence principle holds, having a rocket in deep space accelerating, by conventional mean, at 1g, a floor that is orthogonal to this acceleration, a pedestal resting on this floor, a powered EM drive resting on this pedestal in same configuration, remove the pedestal and one will observe the EM drive hovering above that floor (that is still accelerating at 1g). Meaning we now have a powered EM drive not needing to be "pushed" to accelerate at 1g (there is no longer any interaction between rocket and device).
Stop the conventional thrust of the rocket : the rocket will stop accelerating and proceed as an inertial mass at constant velocity (relative to whatever inertial frame). Let the device escape from an open front bay : it will continue to accelerate at 1g since it was no longer interacting with the rocket when the change in acceleration of the rocket occurred (no interaction => whatever change in rocket trajectory ignored). We now have a "conventionally" accelerating (thrusting) EM drive needing no added force.
So why bother with a Hall thruster ? Just put behind a big dumb powder booster that makes your EM drive accelerate at 1g for a fraction of a second the time it takes for the EM drive to "record" that acceleration as a "starting point". BTW, same argument above could be made if acceleration was 0.5g instead of 1g : this means we now have to add a new intrinsic variable to a moving object. What physical mechanism explains this memory effect of "initial acceleration" into an ongoing acceleration of given magnitude ?Quote...
I trust this shows how the EM Drive is unlike anything humanity has experienced before. So please do not move forward thinking it is like a propellantless Hall thruster or rocket motor that generates thrust when the cavity is filled with microwave energy.
Don't underestimate the aptitude of intelligent people to integrate counter intuitive formal systems when they show internal consistency.
.../...
For weak gravitational field the frequency ratio between top and bottom is ft/fb = (1 + Rs/2rt - Rs/2rb) where Rs is Schwarzschild radius, rt and rb distance from centre of body (earth centre). From there (http://fr.wikipedia.org/wiki/D%C3%A9calage_d%27Einstein#Fr.C3.A9quence_propre_et_fr.C3.A9quence_observ.C3.A9e), sorry this is French wikipedia, I don't find a convenient English resource for the same formula.
For Earth Rs is about 9mm (http://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters), so lets say we have 0.3m altitude difference at earth surface (6.371e6m) => ft/fb = 1 - 3.3e-17
This is one part in 3e16 redshift in frequency.
Likewise any Doppler effect affecting the relative wavelengths (momentums) of photons between forward and backward plates of an accelerating frustum would indeed induce a non 0 net force : this force would always be opposite to the acceleration (ie. never a thrust) and in fact could be interpreted as the inertia of the mass equivalent of energy bouncing back and forth in the cavity (whatever its shape). The time constant of a photon in a Q=10000 about 0.3m across frustum would be like 10µs, at 100W pumped into the frustum there is then on the order of 1e-3 J EM energy content at any given time, that is equivalent to 1.1e-20 kg of mass, or an apparent added "force of inertia" of 1.1e-19N for a spacecraft accelerating at 1g, or equivalently an added weight of 1.1e-19N vertically for a resting frustum on earth.
In summary, within classical frameworks, yes there can be non 0 net force of EM radiation in an accelerating cavity, but this will be vanishingly small forces, and always opposite to acceleration (aka "inertia").
Is it correct ?
Close, those forces are similar to the observed forces. Perhaps @Rodal has the page reference back to my calculation which is what I beleive you are stating.
Edit: I think this was it (have to check)
"
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))"
Zellerium, I am uncertain about if your University allows for this sort of thing or not, but for the purposes of the nascent Wiki under development, would you be willing to provide (later once you have them) some Bills of Materials as well as instructions documenting how you assembled and set up your rig?
...
Dr. Rodal:
Do you think the thrust signiture observed from the null Cannae drive could be due to air currents?
I assume the frustum yielded similar thrusts while in a vacuum and in air, which shows how much the air is effecting thrust. Unless the shape of the Cannae drive led to a significant air current, it seems a symmetric cavity should produce thrust.
Although we may be able to find the resonant frequencies for the frustum using software, changing parameters like the dielectric thickness will change the frequency required. And if we have to use a microwave magnetron then we have to change the frustum's size which is more challenging, but still possible.
However, if we recieve enough money for the variable frequency test a tapered cavity would be a much better option.
I just downloaded EM Pro recently, but I only have experience with 3-D design software (Creo) and Matlab. We may have licenses available for Multiphysics, I'll look into it.
...
I thought this might be an alternative way of measuring small forces. Maybe it could be exploited to make a working model if some one thought it was easier to make.
Speaking of KM, is there anyone out there that has what it takes and is willing to volunteer and set up a wiki or something?
http://en.wikipedia.org/wiki/MediaWiki
I've set up a MediaWiki server before and it wasn't too bad. That is a good platform. I'm simply stretched too thin right now to try it again.
.../...
For weak gravitational field the frequency ratio between top and bottom is ft/fb = (1 + Rs/2rt - Rs/2rb) where Rs is Schwarzschild radius, rt and rb distance from centre of body (earth centre). From there (http://fr.wikipedia.org/wiki/D%C3%A9calage_d%27Einstein#Fr.C3.A9quence_propre_et_fr.C3.A9quence_observ.C3.A9e), sorry this is French wikipedia, I don't find a convenient English resource for the same formula.
For Earth Rs is about 9mm (http://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters), so lets say we have 0.3m altitude difference at earth surface (6.371e6m) => ft/fb = 1 - 3.3e-17
This is one part in 3e16 redshift in frequency.
Likewise any Doppler effect affecting the relative wavelengths (momentums) of photons between forward and backward plates of an accelerating frustum would indeed induce a non 0 net force : this force would always be opposite to the acceleration (ie. never a thrust) and in fact could be interpreted as the inertia of the mass equivalent of energy bouncing back and forth in the cavity (whatever its shape). The time constant of a photon in a Q=10000 about 0.3m across frustum would be like 10µs, at 100W pumped into the frustum there is then on the order of 1e-3 J EM energy content at any given time, that is equivalent to 1.1e-20 kg of mass, or an apparent added "force of inertia" of 1.1e-19N for a spacecraft accelerating at 1g, or equivalently an added weight of 1.1e-19N vertically for a resting frustum on earth.
In summary, within classical frameworks, yes there can be non 0 net force of EM radiation in an accelerating cavity, but this will be vanishingly small forces, and always opposite to acceleration (aka "inertia").
Is it correct ?
Close, those forces are similar to the observed forces. Perhaps @Rodal has the page reference back to my calculation which is what I beleive you are stating.
What do you mean by "similar to the observed forces" ? Quantitatively what my very crude estimations of effect of acceleration on EM net force imbalance are 14 orders of magnitude below observed forces at EW, and that is for 1g acceleration, which is far from acceleration of the frustum (horizontal wise), even taking into account recorded noise.
I should really not put my feet in that but : if Doppler effects are to be given importance ( to the point of wanting to compensate for them ) and related influence of acceleration of device on resonance, then this should be quantitatively assessed. A 30cm journey from one end to the other takes a photon 1ns. In such a short time a 1g accelerating frustum would have added or subtracted only v=1e-8 m/s to the velocity seen by the photon on the "last bounce" (this is very crude !). What is the Doppler effect of such a tiny velocity difference ?
f1/f0 = 1 +or- v/c that would amount to a ratio of 1 +or- 3.3e-17, in agreement with above value for gravitational redshift (equivalently, for the same 1g and 30cm distance). I fail to understand how even a superconducting cavity with a Q of a billion and a super narrow bandwidth would care about such a tiny Doppler shift...
And the net force imbalance induced by this Doppler shift, for 100W pumped into frustum at Q=10000 would be 1.1e-19N, at Q=1e9 would be 1.1e-14N ... (and opposite to acceleration). Basically this is just the "inertial force" of the equivalent EM mass multiplied by acceleration...
Beyond this crude photon model I must admit I don't get the more sophisticated equations, I know this was explained quite a bit. Notsosureofit would you care plugging the same parameters in your formulas and derive values, what a ~30cm frustum would experience as net EM force imbalance due to acceleration at 1g, given a feed of 100W at Q=10000 ? What is wrong with a crude photon model that don't show dependency on frequency that would be correct with your model where I see some f^3 but no acceleration ?
I have : F = - acc * P*Q*L/c^3
F net EM radiation imbalance due to acceleration of frustum
acc acceleration in m/s²
P input power in W
L length of cavity in m
c speed of light
This is not the levels of "thrust" (well, this is not a thrust at all !) experimentally recorded, but is it physically sound ?QuoteEdit: I think this was it (have to check)
"
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))"
I thought this might be an alternative way of measuring small forces. Maybe it could be exploited to make a working model if some one thought it was easier to make.what is the advantage of this method over a hanging torsional pendulum or over a horizontal torsional balance ?
The easiest way to measure small forces is to make them bigger.Much smaller forces have been measured much more accurately for centuries.
The "g" in the formulas is the amount of acceleration needed to make the tapered cavity "look like" a cylindrical one, ie. compensated
Thermal convection forces have plagued radiation pressure measurements since the time of Maxwell, for about 139 years and counting. There is a rich history showing this.
The shape of the Cannae device maximizes the effect of thermal convection effects.
Please notice that the thrust/PowerInput obtained by NASA Eagleworks in a vacuum is only a fraction of the one that they measured in air, which shows quantitatively the huge problem with conducting tests under ambient conditions like Shawyer in the UK and Yang in China have done. But, again, if you don't have a vacuum chamber, there are proven ways to minimize this effect that neither Shawyer nor Yang appear to have utilized.
I strongly advise against performing any Finite Element Analysis calculations unless you have an analyst available that has taken University courses in Finite Element Analysis and has practical experience with such Finite Element packages. If you want to perform FEA you must add to your team such an analyst.
EDIT: If you use the same geometrical dimensions and materials used by NASA, couldn't you use NASA's COMSOL calculations (available in this thread) to assess the frequencies and mode shapes ? (and thus avoid the need to perform any numerical calculations on your own)
Best regards,
Thermal convection forces have plagued radiation pressure measurements since the time of Maxwell, for about 139 years and counting. There is a rich history showing this.
The shape of the Cannae device maximizes the effect of thermal convection effects.
Please notice that the thrust/PowerInput obtained by NASA Eagleworks in a vacuum is only a fraction of the one that they measured in air, which shows quantitatively the huge problem with conducting tests under ambient conditions like Shawyer in the UK and Yang in China have done. But, again, if you don't have a vacuum chamber, there are proven ways to minimize this effect that neither Shawyer nor Yang appear to have utilized.
I strongly advise against performing any Finite Element Analysis calculations unless you have an analyst available that has taken University courses in Finite Element Analysis and has practical experience with such Finite Element packages. If you want to perform FEA you must add to your team such an analyst.
EDIT: If you use the same geometrical dimensions and materials used by NASA, couldn't you use NASA's COMSOL calculations (available in this thread) to assess the frequencies and mode shapes ? (and thus avoid the need to perform any numerical calculations on your own)
Best regards,
Oh! I hadn't found the data from the vacuum test, I assume it is buried in the forum somewhere?
If there isn't strong evidence that a symmetric cavity will work, we will build a frustum.
We could use EW's dimensions if we recieve funding for the variable frequency equipment. However, if we have to use a microwave magnetron we will have to do the FEA. I might be able find someone willing to help.
We don't have a vacuum chamber large enough so we will look into minimizing the affects of convection.
Thank you for the response!
....As the initial photons travel towards one of the ends, and it hits the end-plate, yes it functions as a travelling wave in a waveguide. However, once the wave hits the end it gets reflected (almost perfectly since the skin depth is extremely small compared to the wavelength and hence the losses are negligible). At that point we have standing waves. The high Q of the cavity is a result of these standing waves producing resonance. So instead of a
The frustum is a waveguide that has a strong gradient in the group velocity, near the cut-off modes, relative to the microwave photons moving inside it....
....As the initial photons travel towards one of the ends, and it hits the end-plate, yes it functions as a travelling wave in a waveguide. However, once the wave hits the end it gets reflected (almost perfectly since the skin depth is extremely small compared to the wavelength and hence the losses are negligible). At that point we have standing waves. The high Q of the cavity is a result of these standing waves producing resonance. So instead of a
The frustum is a waveguide that has a strong gradient in the group velocity, near the cut-off modes, relative to the microwave photons moving inside it....
waveguide with travelling waves having a non-zero Poynting vector transmitting energy from one end to the other,
what we have upon reflection is a
closed cavity with standing waves having a self-cancelling zero mean value (over a period) Poynting vector and there is no transmission of energy
(http://www.acs.psu.edu/drussell/Demos/superposition/standing.gif)
So, the question is, do you see your mechanism as resulting into an acceleration vs. time that gives constant acceleration at constant power input, for ever and ever (which involves an energy paradox)
or
do you see your mechanism as just resulting into a one-time short-impulse or Dirac delta-function spike in acceleration only (due to the initial photons hitting the end) upon energizing the cavity ?
Regards,
JR
...
I do not think it will have constant acceleration for constant power input over time, because the matter of the frustum and it's source will experience relativistic effects, on mass, time and length. It takes more than a frustum to make an actual warp drive.
...
...
I do not think it will have constant acceleration for constant power input over time, because the matter of the frustum and it's source will experience relativistic effects, on mass, time and length. It takes more than a frustum to make an actual warp drive.
...
Question: under your interpretation, the Emdrive would have a maximum speed always less than c, because acceleration would eventually decrease until maybe becoming zero due to relativistic effects on the frustum at some speed. Is that correct?
If so, what speed are we talking about? something close to c or much lower?
This topic of the Emdrive's maximum speed and the potentially diminishing acceleration is something that has appeared repeatedly in the discussions, without a clear answer yet because there is no experimental data backing it or disproving it yet.
This notion has also been rebuffed by some people, because assuming a "maximum speed" also assumes a privileged reference frame, which is a big no no in current theories.
I feel there could be a GR explanation, related to the fact that we do have an absolute speed limit: the speed of light, which is the same on all reference frames, including that of the microwaves inside the frustum.
Want to make sure it isn't forgotten that:
Shawyer said to use narrow band source for cavity with shaped ends.
Wideband is for cavity with flat ends.
Thus, Eagleworks is using the wrong type of signal source.
Can't say we didn't tell them.
Concerning obtaining the frequency and mode shape, does your University give you access to a Finite Element analysis package like COMSOL, or ANSYS Multiphysics, etc. so that you could then obtain a numerical solution for any arbitrary geometry and inserted dielectric ?
I thought this might be an alternative way of measuring small forces. Maybe it could be exploited to make a working model if some one thought it was easier to make.what is the advantage of this method over a hanging torsional pendulum or over a horizontal torsional balance ?
Thanks
We used to use a differential ac capacitor to measure displacement.
The reason some people mentioned reduced acceleration at higher velocities, is with classic newtonian thrust, kinetic energy is squared to the speed. EM Drive tech is by some assumed to convert electrical energy directly to kinetic energy (or at least using a different mechanism than action/reaction), which is a linear process. By that statement alone, you can deduce that with constant power input, and not taking into account relativistic effects, the acceleration will reduce, but it will not do so asymptotically. It's a square root. Of course it will force itself into an asymptote because of eventual relativistic effects (For the distant observer). From traveller's PoV, you can still accellerate indefinitely and the traveller's perceived speed can still go to infinity. Relativity is still in tact as a whole.Question: under your interpretation, the Emdrive would have a maximum speed always less than c, because acceleration would eventually decrease until maybe becoming zero due to relativistic effects on the frustum at some speed. Is that correct?
...
I do not think it will have constant acceleration for constant power input over time, because the matter of the frustum and it's source will experience relativistic effects, on mass, time and length. It takes more than a frustum to make an actual warp drive.
...
If so, what speed are we talking about? something close to c or much lower?
This topic of the Emdrive's maximum speed and the potentially diminishing acceleration is something that has appeared repeatedly in the discussions, without a clear answer yet because there is no experimental data backing it or disproving it yet.
This notion has also been rebuffed by some people, because assuming a "maximum speed" also assumes a privileged reference frame, which is a big no no in current theories.
I feel there could be a GR explanation, related to the fact that we do have an absolute speed limit: the speed of light, which is the same on all reference frames, including that of the microwaves inside the frustum.
I thought this might be an alternative way of measuring small forces. Maybe it could be exploited to make a working model if some one thought it was easier to make.what is the advantage of this method over a hanging torsional pendulum or over a horizontal torsional balance ?
Thanks
Notsureofit seems to know from the quote.We used to use a differential ac capacitor to measure displacement.
He might have more experience with it than I. I would guess you can increase the surface of the capacitor to increase your sensitivity. A lock-in amplifier can eliminate noise and amplifiers can further amplify the signal from the capacitor. It is an alternative to other ways of measuring. I'm wondering if there might be a way to tune the rate of natural osculation of the system by applying a small offset DC voltage (of the AC wave to used to measure capacitance) as a way of tuning. There might be some give and take compared to other methods. I haven't ever personally used one.
About the possible interpretation of this effect, if confirmed, I would like to point out that a plane wave implies a modified metric in general relativity. This has been presented in Misner, Thorne, Wheeler, Gravitation at section 35.11 page 961. You can also find a Wikipedia entry (https://en.wikipedia.org/wiki/Monochromatic_electromagnetic_plane_wave) describing it. For the article used in the measurements the situation is more involved as the frustum has not just a single mode but, in principle, each one of these can be seen as propagating in a modified metric. The smaller the input power the smaller the effect. It is my conviction that a full understanding could be achieved with a proper treatment using general relativity. What I have found in literature is overlooking any analysis of the interaction between microwaves and space-time. The effect is miniscule in any case but the interferometer devised at Eagleworks seems well equipped to unveil it.
TheTraveler, the RF generator/amplifier/etc could be placed on the scale as part of the counter weight, no floating RF cables this way. Power supply could come up from the center.RF gen & wide band RF amp need pwr and USB connections. Probably better to feed a single & thin RF cable up through a hole in the teeter totter centre and then to left side EM Drive but leave the electronics on the bench.
There is also need for a down pointing arm from center with a weight for stability.
This setup should not be affected by buckling.
The limit is on acceleration not speed.Yes but only when observed from a reference frame. Traveller's accelleration (from travellers PoV) reduces as a square root and that is not asymptotically (the limit you stated). If it were, speed from the traveller's frame of reference could never grow toward infinity, which it can occording to GR.
Potential USB narrow band RF signal generator / spectrum analyser with frequency adjustable in 1kHz steps and adjustable power output.TheTraveler, the RF generator/amplifier/etc could be placed on the scale as part of the counter weight, no floating RF cables this way. Power supply could come up from the center.RF gen & wide band RF amp need pwr and USB connections. Probably better to feed a single & thin RF cable up through a hole in the teeter totter centre and then to left side EM Drive but leave the electronics on the bench.
There is also need for a down pointing arm from center with a weight for stability.
This setup should not be affected by buckling.
The balance beam will be at least 200mm wide (bit wider than EM Drive external support rods), with through axle & 2 side bearings, so should be no stability issues. Design like kids teeter totter. Simple. KISS.
Roger no thermal buckling or CG movement issues.
The 4 EM Drive external rod supports will sit on one end on the Teeter Totter. Sorry girls I need your Teeter Totter.
....
Thank you for the interesting questions, Dr. Rodal.
I do not think it will have constant acceleration for constant power input over time, because the matter of the frustum and it's source will experience relativistic effects, on mass, time and length. It takes more than a frustum to make an actual warp drive.
For now, I'm not certain that having the resonance occur inside the frustum is necessary. Resonance could occur in an exterior chamber, like pumping a "laser", something to pump the input power. Then inject a tuned coherent pulse of limited bandwidth into the frustum near it's cut-off modes. The objective being, to use the variable refractive index to amplify the momentum toward the small end. By this I mean, the momentum transforms due to the refractive index,
p => p*sqrt(c/vg)
The group velocity depends on location in the frustum and is lowest at the small end. So momentum is amplified toward the small end. The energy is not lost through resistive copper losses, it is absorbed through momentum transfer of the exponentially decaying waves that have been squeezed beyond their cut-off diameter in the waveguide. For these waves, the speed of light has come to a halt and they cannot propagate, so their momentum must be absorbed by the frustum. Where else can it go? They have crossed the event horizon, where c -> 0, the momentum can't escape.
The resonant modes are probably not so close to the cut-off and contribute very little, if anything. There is still a gradient in v group, but a much, much smaller one. I would consider this a different design, one that optimizes Q and very high energy storage over thrust, but the result will work for the same reason.
You also asked me for some equations, graphs and such. I've just started researching here and found an enormous body of information I did not know about. So... it may be a while. :) Any questions you may have on the PV Model and my quantum electrodynamic interpretation of it, I'm happy to assist.
Best Regards,
Todd D.
The limit is on acceleration not speed.Yes but only when observed from a reference frame. Traveller's accelleration (from travellers PoV) reduces as a square root and that is not asymptotically (the limit you stated). If it were, speed from the traveller's frame of reference could never grow toward infinity, which it can occording to GR.
while realizing my knowledge of electromagnetism falls short compared to level that is discussed here, i do have a question about that interesting idea on momentum transfer of the waves :Concerning Todd's formulation, I attach below his reply that was posted in another thread, that may also be of help concerning the above question:
-with the law on conservation of energy in the back of my head -
How can the momentum transfer of a wave be bigger then the energy contained in a photon, as seen in a pure photon rocket ? I believe calculations showed the forces observed in the frustum are many times (100? 1000?) greater then what a photon rocket would be able to produce...
Due to the duality of microwave being a photon particle and a wave at the same time, shouldn't the energy contained in a wave/particle be the same?
Is it because for a photon rocket only a small portion of that energy is used for kinetic motion, while in the momentum transfer a greater part of the energy is transferred? ???
<snip>
Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;
p = h/lambda
wavelength depends on velocity, and v_g is a variable inside the frustum.
That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.
I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.
Todd D.
Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.
And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.
If you insist on using Newtonian mechanics, then you will never understand COM in terms of General Relativity. I have not formulated a "new" theory, I'm using GR correctly. If you learn how to do COM in GR, then you would have no trouble seeing that this does indeed conserve momentum. The fact that you "don't care what is inside" is what is preventing you from learning. The "gravitational" field effect of a variable speed of light, acting on the photons inside the Frustum is what makes it move. If you neglect that it has a gravitational field inside it, then you neglect the very essence of how it works and why momentum is conserved. If you want to neglect GR and "believe" COM is violated, then that is your prerogative.
As for why it was not discovered already, I'm kicking myself in the a** for not thinking of this setup 10 years ago when I realized we can mimic gravity over a limited bandwidth with much less energy than over the full bandwidth of all light and matter waves. When my colleague and I wrote our EGM III paper, we had a resonant cavity like this in mind, but we didn't consider the taper.
Best Regards,
Todd D.
Here is my KISS EMDrive test system rough draught.
The EM Drive will sit on top of but not connected to one end of a balance beam. On the other will be an adjustable counter balance mass. Very low stiction bearings will be used.
The EM Drive end of the balance beam will sit on top of but not connected to a digital load cell with a 0.01g resolution / 0.5kg max and be connected via USB to a laptop running data logger software. Would like more resolution, will see how the budget goes.
The counter balance will be adjusted to produce a down force on the load cell of 0.25kg when the EM Drive is unpowered so to bias the load cell into the middle of it's range.
The frequency and power adjustable RF source will be connected to the EM Drive by a free floating length of coax with SWR matching capability and to the laptop via USB connector. Control of frequency and power will be via software on the laptop.
Fairly long power pulses of of upto 2 minutes will be applied to the EM Drive as per Shawyer's 1st test protocol. http://emdrive.com/feasibilitystudy.html
The idea is to keep this KISS and stay as close to the 1st Shawyer test setup that also used vertical orientation of the EM Drive.
Based on achieving 10mN/kW (~1gf/kW) performance, the desired 0.1gf (10x load cell resolution) will need the application of 100W of RF power.
Desire is to use common 2.4GHz narrow band WiFi based signal generators which can be smoothly varied in frequency and power output to find optimal cavity frequency and energy loading.
As this is a narrow band RF signal, ideally the end caps should be spherical to eliminate end plate variable phase change and to get a much better cavity Q. But being a realist and KISS engineer, who hates to reinvent the wheel, will start with simpler flat plates and will follow the excellent work of Mullerton.
Comments most welcome
Apologies to all. I thought I had read all the older forum pages. Seems I missed quite a few. Just about finished.
What I did find and confirmed via a search is that Shawyer's latest revelation, in an email to Mullerton, was that the Flight Thruster end plates WERE SHAPED seems to have missed making the headlines.
I did read there was quite a bit of speculation during the time the Flight Thruster dimensions were being worked out as to whether the end plates were flat or shaped.
So how we have it from Shawyer himself, the Flight Thruster was designed to have a high Q (narrow bandwidth), use a narrow band RF generator and have shaped end plates. Seems we finally know for sure why the end plates were so thick.
Apologies to all. I thought I had read all the older forum pages. Seems I missed quite a few. Just about finished.
What I did find and confirmed via a search is that Shawyer's latest revelation, in an email to Mullerton, was that the Flight Thruster end plates WERE SHAPED seems to have missed making the headlines.
I did read there was quite a bit of speculation during the time the Flight Thruster dimensions were being worked out as to whether the end plates were flat or shaped.
So how we have it from Shawyer himself, the Flight Thruster was designed to have a high Q (narrow bandwidth), use a narrow band RF generator and have shaped end plates. Seems we finally know for sure why the end plates were so thick.
euhmm... came to the same conclusion...just didn't add the pretty pictures... ;D
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369324#msg1369324
Thanks for the feedback.Here is my KISS EMDrive test system rough draught.
The EM Drive will sit on top of but not connected to one end of a balance beam. On the other will be an adjustable counter balance mass. Very low stiction bearings will be used.
The EM Drive end of the balance beam will sit on top of but not connected to a digital load cell with a 0.01g resolution / 0.5kg max and be connected via USB to a laptop running data logger software. Would like more resolution, will see how the budget goes.
The counter balance will be adjusted to produce a down force on the load cell of 0.25kg when the EM Drive is unpowered so to bias the load cell into the middle of it's range.
The frequency and power adjustable RF source will be connected to the EM Drive by a free floating length of coax with SWR matching capability and to the laptop via USB connector. Control of frequency and power will be via software on the laptop.
Fairly long power pulses of of upto 2 minutes will be applied to the EM Drive as per Shawyer's 1st test protocol. http://emdrive.com/feasibilitystudy.html
The idea is to keep this KISS and stay as close to the 1st Shawyer test setup that also used vertical orientation of the EM Drive.
Based on achieving 10mN/kW (~1gf/kW) performance, the desired 0.1gf (10x load cell resolution) will need the application of 100W of RF power.
Desire is to use common 2.4GHz narrow band WiFi based signal generators which can be smoothly varied in frequency and power output to find optimal cavity frequency and energy loading.
As this is a narrow band RF signal, ideally the end caps should be spherical to eliminate end plate variable phase change and to get a much better cavity Q. But being a realist and KISS engineer, who hates to reinvent the wheel, will start with simpler flat plates and will follow the excellent work of Mullerton.
Comments most welcome
One possible problem I see with your proposed experiment is the coiled coax. There will always be a significant error force from that and there is no simple way of cancelling it out. Maybe a telescoping waveguide feed would solve that problem. The load cell will also be in jeopordy. Too much imbalance will crush it.
Good news is the shaped end plates are no longer speculation nor conjecture. The guy who made the Flight Thruster has told us they are shaped.Apologies to all. I thought I had read all the older forum pages. Seems I missed quite a few. Just about finished.
What I did find and confirmed via a search is that Shawyer's latest revelation, in an email to Mullerton, was that the Flight Thruster end plates WERE SHAPED seems to have missed making the headlines.
I did read there was quite a bit of speculation during the time the Flight Thruster dimensions were being worked out as to whether the end plates were flat or shaped.
So how we have it from Shawyer himself, the Flight Thruster was designed to have a high Q (narrow bandwidth), use a narrow band RF generator and have shaped end plates. Seems we finally know for sure why the end plates were so thick.
euhmm... came to the same conclusion...just didn't add the pretty pictures... ;D
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369324#msg1369324
You certainly did! You also ended up with a bottom-of-the-page post, which are fairly easy to miss; that never helps. :)
The Q's reported in the tables 1 and 2 of http://www.emdrive.com/NWPU2010paper.pdf and in the above quote are much higher than the calculated Q based on the bandwidth.
Chinese did report their cavity bandwidth data:
http://www.emdrive.com/yang-juan-paper-2012.pdf
Interesting. Earlier in the first thread the discussion centered around cavity Q and the need for a high Q. This cavity only has a Q = 1531.
The 2013 paper from NWPU: "It was found that the thruster
cavity made by copper and resonating on the equivalent TE011
mode has a quality factor 320400 and generates total net EM
thrust 411 mN for 1000 W 2.45 GHz incident microwave."
http://iopscience.iop.org/1674-1056/22/5/050301
Zen-In's calculated Q from the bandwidth is correct: Q = f/bandwidthf (by definition)
Can anybody make sense of the discrepancy?
I am afraid that Star-Drive...aka Paul March isn't coming back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
I am afraid that Star-Drive...aka Paul March may not come back. We had such a productive collaboration. That was open source science happening right before the World's eyes.Maybe someone can tell him we've settled down here. Did the tumult from a few of the new thread participants because of the new publicity discourage him?
We'll reach the stars someday, and you're getting us there...one data point at a time.
I am afraid that Star-Drive...aka Paul March may not come back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
I am afraid that Star-Drive...aka Paul March isn't coming back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
I am afraid that Star-Drive...aka Paul March may not come back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
BTW, I think Mr. Shawyer claimed that there was no dielectric inserted into his cavity at all because it was not needed for its functioning. Technically though, that's not possible with materials like copper and aluminum. They instantly oxidize during manufacture of the cavity. So, the standing EM waves will encounter a dielectric on any metallic surface.
I am afraid that Star-Drive...aka Paul March isn't coming back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
Have you heard something to that effect ? I have heard it said that NASA has asked them to not discuss NASA work in any public forum, because of what was written in the media (NASA warping space by accident, NASA working on a Star-Trek spaceship, etc.) .
I'm trying to wrap my head around this, so let's see if i got this right...(in simple wording)while realizing my knowledge of electromagnetism falls short compared to level that is discussed here, i do have a question about that interesting idea on momentum transfer of the waves :Concerning Todd's formulation, I attach below his reply that was posted in another thread, that may also be of help concerning the above question:
-with the law on conservation of energy in the back of my head -
How can the momentum transfer of a wave be bigger then the energy contained in a photon, as seen in a pure photon rocket ? I believe calculations showed the forces observed in the frustum are many times (100? 1000?) greater then what a photon rocket would be able to produce...
Due to the duality of microwave being a photon particle and a wave at the same time, shouldn't the energy contained in a wave/particle be the same?
Is it because for a photon rocket only a small portion of that energy is used for kinetic motion, while in the momentum transfer a greater part of the energy is transferred? ???
COM=conservation of momentum
GR=General Relativity
His answer has to do with the "gravitational field" inside the cavity, which can have different levels of energy :
(in one post he suggested that the experimenters should post a label on the frustum reading "Gravitational Field Inside")
I was wondering about the following:
The tapered frustum's sole purpose is to create a standing EM wave of specific frequency. As far as I remember, a standing wave could also be interpreted as a confined particle in quantum mechanics. Is there any possibilty that the standing waves within the cavity resemble dynamically created exotic matter that shows weird behavior when interacting with the 'normal' matter that the EM-drive is made of?
This is at least similar to some claims made by Dr white. However I am not sure I have properly understood what he meant when he said these things are doing essentially the same thing the QVPT does and (I think?) maybe he said the QVPT and the Warp Interferometry test article got it's negative energy from the vacuum. Anyhow it may be that your supposition aligns with Dr White but i am not completely sure I understand it.
From what I remember, originally there was the Alcubierre "Warp Drive" concept proposed by Mexican physicist Miguel Alcubierre, which required a jupiter-sized mass of dark matter. Then Dr White came up with a refinement of the geometry, so that the amount of dark matter was much less (someone compared it to the mass of the Voyager space probe.) Then Dr White announced his intention to test whether a "space warp" was possible, by using a Michelson interferometer to try to detect a path-length difference when a voltage was applied to a capacitor ring.Maybe there is some of that going on out there. But what i am recalling is from this thread. and I think it may have been Mr March or someone directly in a conversation with Mr March in this thread. Again my memory may be faulty on who but not where. It happened here. :) ...or maybe i am insane. :)
So that stuff was all purely related to Alcubierre "Warp Drive". And of course news media were widely reporting that NASA was researching how to develop a Warp Drive, and the news stories were of course showing pictures of the starship Enterprise from Star Trek. But Shawyer's EMdrive was nowhere in that picture, and was an altogether separate and much less reported story on its own.
Then when the Eagleworks lab got involved in experimental testing to verify the Shawyer EMdrive concept (or Cannae drive, whatever) that's when suddenly the 2 stories began to merge, and speculation was put forth that the EMdrive was somehow a "Q-thruster" and then further that it was a "Warp Drive". Since the actual mechanism - if any - is unknown, what it is seems to depend on who's doing the speculating.
How much power are you planning on putting through that coax? The thicker it gets, the stiffer it gets, which would mess up any delicate movements of the balance beam. My experience is with amateur radio, and there 50 watts is the most you would try to put through something like RG-59 (looks like cable-TV cable). RG-8, which can handle a kilowatt, is about 1 cm in diameter and not very flexible at all.Thanks for the feedback.
Power losses in the cable of course turn into heat...
I am afraid that Star-Drive...aka Paul March isn't coming back. We had such a productive collaboration. That was open source science happening right before the World's eyes.
We'll reach the stars someday, and you're getting us there...one data point at a time.
.....
Amazing how times have changed that now discussing future space applications (even if they are impractical like the flotilla of spaceships to Mars was) is met with such backlash at the one organization that should be inspiring young people to go into mathematics, physics and engineering (instead of being condemned to short trips to near-Earth orbit gazing at our own planet).
:(
......
EDIT: Actually.. the movie implies that, because only very smart people made it into space and procreate there, their descendants should also be quite a bit smarter in general than the old generations on Earth. An evolutionary jump, if you will, caused by extinction pressure.
;)
I'm trying to wrap my head around this, so let's see if i got this right...(in simple wording)while realizing my knowledge of electromagnetism falls short compared to level that is discussed here, i do have a question about that interesting idea on momentum transfer of the waves :Concerning Todd's formulation, I attach below his reply that was posted in another thread, that may also be of help concerning the above question:
-with the law on conservation of energy in the back of my head -
How can the momentum transfer of a wave be bigger then the energy contained in a photon, as seen in a pure photon rocket ? I believe calculations showed the forces observed in the frustum are many times (100? 1000?) greater then what a photon rocket would be able to produce...
Due to the duality of microwave being a photon particle and a wave at the same time, shouldn't the energy contained in a wave/particle be the same?
Is it because for a photon rocket only a small portion of that energy is used for kinetic motion, while in the momentum transfer a greater part of the energy is transferred? ???
COM=conservation of momentum
GR=General Relativity
His answer has to do with the "gravitational field" inside the cavity, which can have different levels of energy :
(in one post he suggested that the experimenters should post a label on the frustum reading "Gravitational Field Inside")
Due to the shape of the frustum, energy is gradually compressed going from the large base to the small base. (energy density differs along the longitudinal axis).
This energy increase also causes a denser gravitational field, effectively slowing down electromagnetic waves, who transfer part of their momentum energy to the frustum...
I can more or less see how "gravitational drag" can cause a forward motion for wave moving towards the small end... but what about the returning waves?
Do they accelerate again when the gravitational field inside the frustum decreases (going from small to large base) , hence nullifying the forward momentum..
or
do they keep their lower energy state on the way back, hence slowly dying out to zero after X bounces?
or.. did i completely miss the point? :'(
How much power are you planning on putting through that coax? The thicker it gets, the stiffer it gets, which would mess up any delicate movements of the balance beam. My experience is with amateur radio, and there 50 watts is the most you would try to put through something like RG-59 (looks like cable-TV cable). RG-8, which can handle a kilowatt, is about 1 cm in diameter and not very flexible at all.Thanks for the feedback.
Power losses in the cable of course turn into heat...
Did a few years as a ham. You are right. Cable heat losses need to be considered. Will be very small. Max power will be 100W.
What I plan to do is not a lot different to how Shawyer tests is cryo EM Drive variant as attached. Note the scale under the cryo EM Drive and the other above left?
He has been doing this since 2003 or before. Why reinvent the wheel? Follow the path he has made.
BTW, I think Mr. Shawyer claimed that there was no dielectric inserted into his cavity at all because it was not needed for its functioning. Technically though, that's not possible with materials like copper and aluminum. They instantly oxidize during manufacture of the cavity. So, the standing EM waves will encounter a dielectric on any metallic surface.Would a copper or aluminium (british :) ) alloy, one that does not oxidize easily, do the trick or would that never provide enough reflectivity for the microwaves?
EDIT: Actually.. the movie implies that, because only very smart people made it into space and procreate there, their descendants should also be quite a bit smarter in general than the old generations on Earth. An evolutionary jump, if you will, caused by extinction pressure.
;)
which goes against current fact: the 10% smarter people on Earth seems to procreate much more slowly than the other 90%.
maybe this trend is older than we think and is the reason why we are still stuck to Earth.
Eagleworks mounted their PA on the balance beam. The frequency source could also be custom made and mounted on the balance beam. That would eliminate the coax problem.Here is what is inside the shiny metal cylinder. An EM Drive with a superconducting inner surface.
Interesting photograph; I have not seen it before. The experiment is nicely setup with very good shielding for air currents. But I don't see how it can be called cryogenic. It looks like the Nitrogen dewar is just supplying dry Nitrogen. The apparatus inside the clear boxes and sitting on a postage scale is not a dewar. Unless he has found a supplier of room temperature superconductors it is not a superconductor test. Superconducting cavities have to be cooled with liquid Helium and to keep the lHe from boiling off in a flash the lHe dewar has to be surrounded by a liquid Nitrogen dewar. A high vacuum has to separate the dewars from everything and high IR reflective surfaces and other exotic contrivances are needed. Otherwise the cryogens boil off and the whole thing turns into a missile. High temperature superconductors are easier to work with because they only require liquid Nitrogen. The second picture shows my crufty rotating magnetic field setup. The white thing is a styrofoam container filled with liquid Nitrogen and the dut (device under test).
Maybe someone can tell him we've settled down here. Did the tumult from a few of the new thread participants because of the new publicity discourage him?
As far as I can tell, I am not the only one to have thought to a general relativity effect here. This paper (http://arxiv.org/abs/1302.5690) uses a modified version of Einstein equations to explain what is going on in a conical resonant cavity without violating momentum conservation. The point is that the author uses a weak perturbation approximation and I do not know if this is fully justified.
The weakest part of the theory seems to be that there is no clear way of preventing large gravitational effects due to the magnetic field of the Earth, as predicted by Eq. (17)
From what I remember, originally there was the Alcubierre "Warp Drive" concept proposed by Mexican physicist Miguel Alcubierre, which required a jupiter-sized mass of dark matter. Then Dr White came up with a refinement of the geometry, so that the amount of dark matter was much less (someone compared it to the mass of the Voyager space probe.) Then Dr White announced his intention to test whether a "space warp" was possible, by using a Michelson interferometer to try to detect a path-length difference when a voltage was applied to a capacitor ring.Maybe there is some of that going on out there. But what i am recalling is from this thread. and I think it may have been Mr March or someone directly in a conversation with Mr March in this thread. Again my memory may be faulty on who but not where. It happened here. :) ...or maybe i am insane. :)
So that stuff was all purely related to Alcubierre "Warp Drive". And of course news media were widely reporting that NASA was researching how to develop a Warp Drive, and the news stories were of course showing pictures of the starship Enterprise from Star Trek. But Shawyer's EMdrive was nowhere in that picture, and was an altogether separate and much less reported story on its own.
Then when the Eagleworks lab got involved in experimental testing to verify the Shawyer EMdrive concept (or Cannae drive, whatever) that's when suddenly the 2 stories began to merge, and speculation was put forth that the EMdrive was somehow a "Q-thruster" and then further that it was a "Warp Drive". Since the actual mechanism - if any - is unknown, what it is seems to depend on who's doing the speculating.
Or perhaps they are connected as there are countless examples I can give in physics where what was supposed to be earlier theories (thought to be very different at the time) they turned out to be incomplete parts of a bigger theory encompassing them. Many examples: Schrodinger wave equation and Heissenberg's matrix formulation, Five consistent versions of string theory were developed until it was realized in the mid-1990s that they were different limits of a conjectured single 11-dimensional theory now known as M-theory. etc etc I can go on and on...From what I remember, originally there was the Alcubierre "Warp Drive" concept proposed by Mexican physicist Miguel Alcubierre, which required a jupiter-sized mass of dark matter. Then Dr White came up with a refinement of the geometry, so that the amount of dark matter was much less (someone compared it to the mass of the Voyager space probe.) Then Dr White announced his intention to test whether a "space warp" was possible, by using a Michelson interferometer to try to detect a path-length difference when a voltage was applied to a capacitor ring.Maybe there is some of that going on out there. But what i am recalling is from this thread. and I think it may have been Mr March or someone directly in a conversation with Mr March in this thread. Again my memory may be faulty on who but not where. It happened here. :) ...or maybe i am insane. :)
So that stuff was all purely related to Alcubierre "Warp Drive". And of course news media were widely reporting that NASA was researching how to develop a Warp Drive, and the news stories were of course showing pictures of the starship Enterprise from Star Trek. But Shawyer's EMdrive was nowhere in that picture, and was an altogether separate and much less reported story on its own.
Then when the Eagleworks lab got involved in experimental testing to verify the Shawyer EMdrive concept (or Cannae drive, whatever) that's when suddenly the 2 stories began to merge, and speculation was put forth that the EMdrive was somehow a "Q-thruster" and then further that it was a "Warp Drive". Since the actual mechanism - if any - is unknown, what it is seems to depend on who's doing the speculating.
And besides that, Paul March was initially involved with research on Prof Woodward's "Mach Effect" theory, which is again something altogether different from Alcubierre warp drive and EMdrive. Mach Effect as of yet cannot be claimed to violate the established laws of physics, and is supposedly a prerequisite or necessary consequence of Einstein's Relativity.
But so the Woodward Mach Effect experiments were about oscillating masses, weren't they? They were not the same type of apparatus as the EMdrive.
So when I see people mentioning warp drive, Woodward's theory, and EMdrive all in the same thread, it kind of looks like the lines are being blurred here. These things originally started out as completely distinct from each other - they were 3 separate things - and now it looks like they're all being mashed together in the thread discussions. Perhaps it's because the same researchers at Eagleworks have been involved in investigating all 3 things.
Eagleworks mounted their PA on the balance beam. The frequency source could also be custom made and mounted on the balance beam. That would eliminate the coax problem.Here is what is inside the shiny metal cylinder. An EM Drive with a superconducting inner surface.
Interesting photograph; I have not seen it before. The experiment is nicely setup with very good shielding for air currents. But I don't see how it can be called cryogenic. It looks like the Nitrogen dewar is just supplying dry Nitrogen. The apparatus inside the clear boxes and sitting on a postage scale is not a dewar. Unless he has found a supplier of room temperature superconductors it is not a superconductor test. Superconducting cavities have to be cooled with liquid Helium and to keep the lHe from boiling off in a flash the lHe dewar has to be surrounded by a liquid Nitrogen dewar. A high vacuum has to separate the dewars from everything and high IR reflective surfaces and other exotic contrivances are needed. Otherwise the cryogens boil off and the whole thing turns into a missile. High temperature superconductors are easier to work with because they only require liquid Nitrogen. The second picture shows my crufty rotating magnetic field setup. The white thing is a styrofoam container filled with liquid Nitrogen and the dut (device under test).
According to Shawyer it is designed to be cooled by liquid Nitrogen and it's super-conducting surfaces are formed from YBCO thin films on sapphire substrates.
Having had time to think about it. the person said one is just an "introverted warp" drive. compared to the WI article which is an extroverted warp drive. so maybe it's searchable...From what I remember, originally there was the Alcubierre "Warp Drive" concept proposed by Mexican physicist Miguel Alcubierre, which required a jupiter-sized mass of dark matter. Then Dr White came up with a refinement of the geometry, so that the amount of dark matter was much less (someone compared it to the mass of the Voyager space probe.) Then Dr White announced his intention to test whether a "space warp" was possible, by using a Michelson interferometer to try to detect a path-length difference when a voltage was applied to a capacitor ring.Maybe there is some of that going on out there. But what i am recalling is from this thread. and I think it may have been Mr March or someone directly in a conversation with Mr March in this thread. Again my memory may be faulty on who but not where. It happened here. :) ...or maybe i am insane. :)
So that stuff was all purely related to Alcubierre "Warp Drive". And of course news media were widely reporting that NASA was researching how to develop a Warp Drive, and the news stories were of course showing pictures of the starship Enterprise from Star Trek. But Shawyer's EMdrive was nowhere in that picture, and was an altogether separate and much less reported story on its own.
Then when the Eagleworks lab got involved in experimental testing to verify the Shawyer EMdrive concept (or Cannae drive, whatever) that's when suddenly the 2 stories began to merge, and speculation was put forth that the EMdrive was somehow a "Q-thruster" and then further that it was a "Warp Drive". Since the actual mechanism - if any - is unknown, what it is seems to depend on who's doing the speculating.
And besides that, Paul March was initially involved with research on Prof Woodward's "Mach Effect" theory, which is again something altogether different from Alcubierre warp drive and EMdrive. Mach Effect as of yet cannot be claimed to violate the established laws of physics, and is supposedly a prerequisite or necessary consequence of Einstein's Relativity.
But so the Woodward Mach Effect experiments were about oscillating masses, weren't they? They were not the same type of apparatus as the EMdrive.
So when I see people mentioning warp drive, Woodward's theory, and EMdrive all in the same thread, it kind of looks like the lines are being blurred here. These things originally started out as completely distinct from each other - they were 3 separate things - and now it looks like they're all being mashed together in the thread discussions. Perhaps it's because the same researchers at Eagleworks have been involved in investigating all 3 things.
Shawyer reports on that unit:Eagleworks mounted their PA on the balance beam. The frequency source could also be custom made and mounted on the balance beam. That would eliminate the coax problem.Here is what is inside the shiny metal cylinder. An EM Drive with a superconducting inner surface.
Interesting photograph; I have not seen it before. The experiment is nicely setup with very good shielding for air currents. But I don't see how it can be called cryogenic. It looks like the Nitrogen dewar is just supplying dry Nitrogen. The apparatus inside the clear boxes and sitting on a postage scale is not a dewar. Unless he has found a supplier of room temperature superconductors it is not a superconductor test. Superconducting cavities have to be cooled with liquid Helium and to keep the lHe from boiling off in a flash the lHe dewar has to be surrounded by a liquid Nitrogen dewar. A high vacuum has to separate the dewars from everything and high IR reflective surfaces and other exotic contrivances are needed. Otherwise the cryogens boil off and the whole thing turns into a missile. High temperature superconductors are easier to work with because they only require liquid Nitrogen. The second picture shows my crufty rotating magnetic field setup. The white thing is a styrofoam container filled with liquid Nitrogen and the dut (device under test).
According to Shawyer it is designed to be cooled by liquid Nitrogen and it's super-conducting surfaces are formed from YBCO thin films on sapphire substrates.
OK I see how that works now; just a liquid Nitrogen dewar with the dut suspended in it. Very similar to my setup. Nitrogen boil-off will affect the lower scale but not the one that supports the dut so much. I would imagine there is a lot of boil-off during a test. YBCO thin films have high AC losses; typically above 60 Hz. No doubt these are specially designed to minimize those lossses.
Small signal testing at 77 deg K confirmed the design, with a Q of 6.8x106 being measured
Shawyer reports on that unit:Eagleworks mounted their PA on the balance beam. The frequency source could also be custom made and mounted on the balance beam. That would eliminate the coax problem.Here is what is inside the shiny metal cylinder. An EM Drive with a superconducting inner surface.
Interesting photograph; I have not seen it before. The experiment is nicely setup with very good shielding for air currents. But I don't see how it can be called cryogenic. It looks like the Nitrogen dewar is just supplying dry Nitrogen. The apparatus inside the clear boxes and sitting on a postage scale is not a dewar. Unless he has found a supplier of room temperature superconductors it is not a superconductor test. Superconducting cavities have to be cooled with liquid Helium and to keep the lHe from boiling off in a flash the lHe dewar has to be surrounded by a liquid Nitrogen dewar. A high vacuum has to separate the dewars from everything and high IR reflective surfaces and other exotic contrivances are needed. Otherwise the cryogens boil off and the whole thing turns into a missile. High temperature superconductors are easier to work with because they only require liquid Nitrogen. The second picture shows my crufty rotating magnetic field setup. The white thing is a styrofoam container filled with liquid Nitrogen and the dut (device under test).
According to Shawyer it is designed to be cooled by liquid Nitrogen and it's super-conducting surfaces are formed from YBCO thin films on sapphire substrates.
OK I see how that works now; just a liquid Nitrogen dewar with the dut suspended in it. Very similar to my setup. Nitrogen boil-off will affect the lower scale but not the one that supports the dut so much. I would imagine there is a lot of boil-off during a test. YBCO thin films have high AC losses; typically above 60 Hz. No doubt these are specially designed to minimize those lossses.QuoteSmall signal testing at 77 deg K confirmed the design, with a Q of 6.8x106 being measured
An EM Drive with a Q of 6,800,000! Massive!
Shawyer reports on that unit:QuoteSmall signal testing at 77 deg K confirmed the design, with a Q of 6.8x106 being measured
An EM Drive with a Q of 6,800,000! Massive!
Me as well. I am still licensed but not very active.How much power are you planning on putting through that coax? The thicker it gets, the stiffer it gets, which would mess up any delicate movements of the balance beam. My experience is with amateur radio, and there 50 watts is the most you would try to put through something like RG-59 (looks like cable-TV cable). RG-8, which can handle a kilowatt, is about 1 cm in diameter and not very flexible at all.Thanks for the feedback.
Power losses in the cable of course turn into heat...
Did a few years as a ham. You are right. Cable heat losses need to be considered. Will be very small. Max power will be 100W.
TravellerInteresting suggestions for your 1st post. Most appreciated. Welcome to the forum.
I strongly suggest you do not place your "mass displacement measurement device" underneath the drive unit. If you invert your thinking and make the opposite end of the fulcrum lever "heavier" such that it places a small but measurable force on the scale, you can data log the hopefully rising-value differences on activation. The reasoning behind this is that your scales "might" be impacted by a grav-wave event originating from the em-drive, creating a chaotic temporal event stream.
You may also need to consider the geometric shape of the end caps.
I suggest you have a browse though data on Schmidt-Cassegrain telescopes for the optical path folding models employed and their direct relevance to the end cap shapes. Consider the possibility for the existence of a focal-point inside the actual tube assembly "that has not been mentioned in the literature", and where this point may occur relative to the end caps. Also consider the ability to extend the tubes physical length with simple mechanical sliding action end cap(s). These factors could impact the deliberate creation of a specific point-of-intersection and as such an area of modified intensity relative to the internal space of the unit. The energy imbalances.. could be interesting.
Or
Consider end cap shapes as a geometric means of creating a parallel-path guide for simple reflection/refraction in a laser-like mode
I have another question, is there any official statement that NASA is working on warp field experiments? Just for the Wikipedia article on the topic.
Mr March told us recently back in the thread that they had a small positive signal on the warp interferometry front.
I have another question, is there any official statement that NASA is working on warp field experiments? Just for the Wikipedia article on the topic.Mr March told us recently back in the thread that they had a small positive signal on the warp interferometry front.
Here is my KISS EMDrive test system rough draught.
Although most of what's being discussed here concerns the static force produced by an EmDrive, I would like to look ahead to the dynamics in free space. In this regard, and needing no recourse to relativity for low velocities, all types of propellantless propulsion device are created equal; i.e. we model them with constant input power which results in a constant thrust, which in turn produces a constant acceleration. A little high school physics and a dash of algebra (see below) should suffice to convince you that, for any and all such devices, there exists a break-even velocity, above which more energy has been produced than has been consumed. As the device continues to further accelerate, a continuous source of free power is available. Thus we have not only perpetual motion, but free energy to boot.This is an adjunct to my overunity analysis for all propellantless propulsion craft when allowed to move subrelativistically in free space. This time we'll use the mundane expressions for cars on roads, rockets and all the familiar things that do not employ floobie dust in their operation. Let's look at an ideal car on a flat road using ideal tyres. The constants of the motion this time are only P (engine power) and m (all up mass). Now we have a velocity-dependent thrust F and variable velocity and acceleration. Now our Newtons/Watt coefficient 'k' also varies with velocity. We only need two equations to sort this all out and to demonstrate its mundanity.
It is worthwhile to quantify the value of this break-even velocity, which turns out to be a very simple expression. The relevant equations we use (symbols having their usual meaning) are:
k := F/P in Newton/Watt
v = a t = (F/m) t
Ein = P t
Eout = 0.5 m v2
From the first 2 equations we get
t = (m v) / (k P)
At breakeven, Ein= Eout and v := v0
or
2 P m v0 / (k P) = mv02
so
v0 = 2/k
Armed with this expression, the performance of any propellantless propulsion device may be examined, if its 'k' value is known.
Or perhaps they are connected as there are countless examples I can give in physics where what was supposed to be earlier theories (thought to be very different at the time) they turned out to be incomplete parts of a bigger theory encompassing them. Many examples: Schrodinger wave equation and Heissenberg's matrix formulation, etc etc
Quote from: sanmanSo if it's the standing wave inside the resonant cavity which is losing energy, then how is that energy being converted into momentum? If the standing wave is pushing on the cavity in a net direction, then how is that standing wave creating an asymmetric radiation pressure inside the cavity? How does the asymmetric shape of the cavity result in asymmetric radiation pressure? Shouldn't radiation pressure inside a cavity always be symmetric?
GoatGuy in reply to sanman:
…then how is the energy being converted to momentum… is one of the fundamental questions which physicists are arguing over. The notion is that the asymmetry of the cone as a waveguide for RF energy realizes a net force away from the small end as the RF wave stream propagates outward and out the end.
This is my gross simplification, but it has a large analogy to help visualize the principle(s) involved: the classic chemical rocket engine.
If one thinks of a chemical rocket engine combustion chamber as NOT a combustion chamber, but merely a round sphere full of high pressure gas, if the sphere is unperforated, obviously there is no gas escape, and no net thrust. No matter how much pressure is in the theoretical sphere. Now, poke a hole in it. The entrained gas will escape. The speed with which it escapes depends on its viscosity, the size of the hole, its density and the speed of sound in the gas, and the interior pressure. The thrust can be either measured or calculated with relative ease. Yet, this is not the highest thrust that the pierced sphere can produce.
Higher thrust can be produced by having an expansion nozzle on the other side of the hole. How's this? Simple enough: the exhaust stream is still pressurized, and will expand in 3 dimensions, so its cross sectional area is also increasing. This too is an outward radial pressure. If not captured (from a simple hole), then it is lost thrust/force. If the expanding gas though impinges on the exhaust cone as it expands outward, the outward expansion is vectored “downward”. Change of momentum vector results in more thrust.
Same gas, more thrust.
(This is one of the chief reasons there are shock diamonds in jet and transparent rocket thrust.)
_______
Now, take the analogy back to the EM-thruster regime. And a very brief review of electromagnetic principles. The first is, that when one reflects an electromagnetic wave, there will be momentum transfer orthogonal to the net moment vector change. Fancy wording, but what it means is this. IF you reflect an electromagnetic wave 180°, or exactly backwards at 100% efficiency (no loss), the reflection will produce a force F which equal to 2E/c. (E = energy, c is speed of light). 1 joule of reflected energy will produce a force of 6.67×10⁻⁹ newton-seconds.
(Note that this applies to light itself. Hence why giant reflectors of sunlight in space might make useful force generators someday. The light is “free”)
Now, imagine instead that we are reflecting the EMR (electromagnetic radiation) only 90°, at a right angle. The moment change will be the same, but the vector isn't ½(180°) but ½(90°) = 45°. The force will depend on the grazing angle, but just suffice to say that we'd realize something closer to E/c instead of 2E/c.
(Again in the solar-sail idea, if one were to fold the solar sail at right angles, and present the corner to the Sun, obviously one side would reflect sunlight away at right angle, and the other side would reflect the other way. The outward force would cancel. But there'd still be a net push. Only ½ that of the reflected backward geometry.)
OK, enough EMF theory. The point is clear: reflected EMR generates a force which depends on the angle of reflectance and the power of the EMR being reflected.
You might want to re-read that!
The principle of the EM-Thruster is that it is a cone of (at this point) constant angle. Looks like about 30° to me or so. Like the rocket-engine, the "high pressure gas" or intense EMR is injected at the small end. Being standing waves in a resonant structure, it bounces around a lot, making its way outward after many reflections. Every time it reflects, it imparts a bit of force against the angled surface of the cone.
This results (as the theory goes) in an amplification of imparted momentum-vector change force. The purveyors of the idea go on to theorize that the amplification should depend on the number of times the EMR wave reflects before exit (or diminishment from lossy-ohmic resistance by the copper metal each reflection). This is actually a rather reasonable idea. The trick though is to keep the RF energy entrained in that cone for as many reflections as is possible while also maximizing the cone's 'exhaust angle'. (i.e. make it a loooooong pencil of a cone, and the angle is so small that there would be very little net propulsive force. But you'd get zillions of reflections. Make it quite wide, and you get good force from each reflected wavelet, but they won't hang out in the cone very long. So, not much net force.)
ANYTHING that I've heard so far seems to rest upon the above idea. Which is fine, because its solid physics. It even explains why someone got the thought of putting a dielectric back there at the concentrated end, to try to keep the EMR in-tube longer. More reflections. Keeping the energy in-tube.
But where the principle goes “crazy” is in supposing that the Q of a EMR reflective cone -and-dielectric-system- can be engineered up to the giga Q level or higher (through superconduction). Obviously, not for an open-ended system. So far (and the images are surprisingly hard to find), I believe that the cone is not open ended, but is capped with a flat reflector. Again, to entrain the EMR in the cone for as many reflections as possible. (and the only way to get Q above about 100 or so for 30° angle cones).
So, we must wait and see. Tho' my electromagnetic theory is pretty solid, I really haven't spent significant time analyzing the train-of-physics that is concocted to support the idea that thrust is dependent on power² (which it should not be!), or of EMR frequency² (which it should not be!).
Lastly, there is a kind of “esthetic solution” to the problem of the high-output devices violating conservation of energy above W/F (watts of power per newtons of force) m/s (meters per second velocity)… sort of. The first is, when the device accelerates, the reflecting EMR inside the cone is bouncing off surfaces which are also accelerating; though infinitesimal, each reflected wave will lose energy, lowering (widening) its wavelength. Since by its nature, resonant systems have a sharper-and-sharper frequency of resonance as Q increases, the wave-system will no longer be in resonance, and won't optimally reflect endlessly. This is helpful in solving the free-energy-device problem, though not complete.
The actual conservation of energy solution comes from noting that in any reflected momentum system, one cannot derive more momentum energy from the energy reflected, than the reflected energy itself.
Sounds circular? It is. But it also works. Bounce a fast-moving glass ball bearing back and forth between large glass reflective surfaces, and it will bound perhaps thousands of times (losing near-all of its kinetic energy to sound (tick-tick-tick…) and to heat). Put the reflectors though on perfect bearings (so that they might accelerate). The ball bearing will only now bounce a few dozen times. If one calcultes how much kinetic energy is imparted to the moving reflector wall, its easy to show that no more kinetic energy than what was within the bearing's frame of reference is imparted to the accelerating reflector. In a perfectly coupled system, the energy transfer would be 100%. The ball would come to rest, and the moving reflector would have all its original kinetic energy added to whatever Ek it had to begin with.
This then looks (to me) like the same system. The EM-Drive concept is bouncing the EMR around, transforming its electromagnetic energy into kinetic thrust energy, with some limit, which is very probably asymptotic to the input energy.
Which would be just fine. Exactly what electric motors do all the time. Transforming electromagnetic energy to kinetic energy. The trick is to find a way to "do this" and also limit the transfer of kinetic energy to that imposed by the basic rocket equation. (Which limits imparted kinetic energy in the vehicle to 1/2 the kinetic energy of the exhaust, integrated over the flight of the vessel.)
GoatGuy
Now, take the analogy back to the EM-thruster regime. And a very brief review of electromagnetic principles. The first is, that when one reflects an electromagnetic wave, there will be momentum transfer orthogonal to the net moment vector change. Fancy wording, but what it means is this. IF you reflect an electromagnetic wave 180°, or exactly backwards at 100% efficiency (no loss), the reflection will produce a force F which equal to 2E/c. (E = energy, c is speed of light). 1 joule of reflected energy will produce a force of 6.67×10⁻⁹ newton-seconds.If you want to quote people who explain physics to you, I'd caution you to first check that they understand some physics. Because what is written there is nonsense. It's not even dimensionally correct.
As far as I can tell, I am not the only one to have thought to a general relativity effect here. This paper (http://arxiv.org/abs/1302.5690) uses a modified version of Einstein equations to explain what is going on in a conical resonant cavity without violating momentum conservation. The point is that the author uses a weak perturbation approximation and I do not know if this is fully justified.
The blasted thing goes faster and that is an increase in momentum. Unless you show where the opposite momentum is then it violates conservation of momentum. It can't get any simpler than that.
Satellite Propulsion Research Ltd (SPR Ltd) a small UK based company, has demonstrated a remarkable new space propulsion technology. The company has successfully tested both an experimental thruster and a demonstrator engine which use patented microwave technology to convert electrical energy directly into thrust. No propellant is used in the conversion process. Thrust is produced by the amplification of the radiation pressure of an electromagnetic wave propagated through a resonant waveguide assembly.
Warp Drive is a purely FTL thing and doesn't claim to have anything to do with conventional displacement or momentum as we know it. And neither Mach Effect nor EMdrive claim to be able to go FTL, even though they are claiming a novel mechanism for displacement.
I hear you, but the main salient thing for me is that the EMdrive is supposed to be a photon rocket - the resonant cavity is not a closed chamber but is actually a chamber with a hole in it (the waveguide end), just as the combustion chamber of a conventional rocket has a hole in it.
So photons are shooting out one end of the EMdrive, just as photons would shoot out one end of a photon rocket, just as propellant shoots out the end of a conventional chemical rocket. What differentiates EMdrive from a traditional photon rocket, is that the photons have been drained of a lot more momentum due to bouncing around in the waveguide first before exiting. This is analogous to the way an expansion nozzle and bell allow the propellant exhaust particles to bounce around more and transfer more of their momentum to the rocket before exiting.
So maybe it's best to start with the picture of a photon rocket in your head, since a photon rocket doesn't violate Conservation of Momentum.
Warp Drive is a purely FTL thing and doesn't claim to have anything to do with conventional displacement or momentum as we know it. And neither Mach Effect nor EMdrive claim to be able to go FTL, even though they are claiming a novel mechanism for displacement.
Regarding FTL - can I beg to differ?
Everything in the universe warps space-time. A rocket at rest warps space-time. An accelerating rocket warps it more.
IMHO - warping space-time to infinity still brings us to the speed of light because the speed of gravity (the warp) is limited to c. The EM Drive has nothing to do with FTL and I personally don't think FTL exists; in my mind the speed of light is the speed of reality.
http://en.wikipedia.org/wiki/Speed_of_gravity (http://en.wikipedia.org/wiki/Speed_of_gravity)
So the crux of the issue for me, is that photons and matter particles behave differently, and are Apples & Oranges which cannot be judged by the same standards:
When you fully drain the momentum of a particle of propellant/matter (wrt your reference frame), then its velocity drops all the way down to stationary - but when you fully drain a photon of its momentum (wrt your reference frame), then it drops out of existence (ie. fades to nothing), because it loses energy rather than losing velocity.
So:
Photon Propellant != Matter Propellant
Matter is persistent, and you can see that exhaust hanging around after it's left the rocket.
Photons are not persistent, so they can disappear and leave you scratching your head about who/what was pushing your rocket to begin with.
....
Todd,
It is exciting to read your explanation about exponentially decaying waves that have been squeezed beyond their cut-off diameter in the waveguide. You write very clearly.
It's great that you found your way into this thread :)
Please see the following reference (https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583, click "Get PDF" to download the paper for free):
It is shown that all modes run continuously from travelling waves through a transition to an evanescent (exponentially decaying) wave region and the value of the attenuation increases as they approach the cone vertex.
A strict distinction between pure travelling waves and pure evanescent (exponentially decaying) waves cannot be achieved for conical waveguide.
One mode after the other reaches cutoff in the tapered hollow metallic waveguide as they approach the cone vertex.
Unfortunately, this analysis is for an open waveguide, not for a closed cavity, but the fact that a strict distinction between pure travelling waves and pure evanescent waves cannot be achieved for a conical waveguide, also has implications for modes approaching cutoff in the truncated cone cavity.
ADDENDUM:
One thing that has not been explored is whether these truncated cones are being prematurely ended towards the cone vertex. The tested designs are almost cylindrical.
Roger Shawyer has progressively (but very slowly with time) increased the cone angle of his truncated cones, culminating in the superconducting design he unveiled last October 2014. NASA Eagleworks and Yang in China have truncated cone designs that look like earlier Shawyer designs, with smaller cone angles.
For reference. the tangent of the cone's half angle thetaw and the cone's half angle thetaw, in ascending order, for the following cases are:
(Notice how Shawyer progressively increased the cone's half-angle, with time, in his experimental designs, by a factor of 7 in the tangent of the half-angle)
Example (and geometry) { Tan[thetaw],thetaw (degrees) }
Shawyer Experimental {0.104019, 5.93851}
Shawyer Fligth Thruster {0.19086, 10.8055}
Shawyer Demo {0.219054, 12.3557}
NASA Eagleworks frustum {0.263889, 14.7827}
Egan's example {0.36397 , 20}
Prof. Juan Yang (2014) {0.4538, 24.4 }
Shawyer Superconducting 2014 {0.7002, 35}
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
The people looking at running experiments here are (understandably) also looking at earlier designs with small cone angles and prematurely terminated before reaching the vertex. The group from a university was looking at running experiments with perfectly cylindrical geometry.
Given the latest write-up by Shawyer (concerning his choice of R1 being too large) it appears that what you are bringing up concerning modes near cutoff has not yet been appreciated or explored, as the researchers are not focusing on general wave solutions in the complex plane containing simultaneously both real and imaginary components.
Best regards, :)
PS: @aero has valiantly attempted to run a full analysis, of general waves, containing simultaneously both real and imaginary components, using MEEP. Unfortunately MEEP is finite difference code and hence he has only been able to run 2-D simulations (due to computer time limitations). It is known that this problem (truncated cone) is 3-D, as a 2-D analysis cannot simulate very important features of the geometry. The MEEP solutions have also been very difficult to interpret, because of the lack of suitable post-processing software to explore the solutions.
@Mulletron envisioned a completely conical EM Drive, terminating at the vertex (at the beginning of the thread when we were all trying to explore all possibilities with an open mind). A perfect cone may not be the best solution because in a perfect cone ALL modes are cut-off and hence there will not be any resonance, but in reality it is impossible to have a perfect cone, since the vertex will always terminate with a finite dimension (not a point). I explored some time ago some geometries, and it looks like there is plenty of room to explore truncated cones that terminate at different distances from the cone vertex.
So the crux of the issue for me, is that photons and matter particles behave differently, and are Apples & Oranges which cannot be judged by the same standards:
When you fully drain the momentum of a particle of propellant/matter (wrt your reference frame), then its velocity drops all the way down to stationary - but when you fully drain a photon of its momentum (wrt your reference frame), then it drops out of existence (ie. fades to nothing), because it loses energy rather than losing velocity.
So:
Photon Propellant != Matter Propellant
Matter is persistent, and you can see that exhaust hanging around after it's left the rocket.
Photons are not persistent, so they can disappear and leave you scratching your head about who/what was pushing your rocket to begin with.
Maybe the experimenters need to vary the angles of that waveguide, so that you have a series of cases where you tap greater and greater amounts of energy from the photons. The steeper and longer the waveguide, the more energy you're draining (transferring to your rocket/apparatus as momentum). The shallower the waveguide, the less energy you're draining (transferring to your rocket/apparatus as momentum).
Shouldn't the experimenters be trying to measure the energy of the photons that leave the resonant cavity via the waveguide exit? Wouldn't establishing some sort of correlation there be useful for proof of principle??
What you are describing is just red shift. I think. It is very confused.
In an ordinary rocket the propellent has no momentum with respect to the rockets reference frame. You burn it and give it a huge momentum with respect to the rockets reference frame. In reaction the rocket gets a huge momentum in the other direction. In the original reference frame they both have huge momentum gain in opposit directions. That is how conservation of momentum works.
A photon rocket is not much different. A photon has some amount of momentum despite being massless. As the photon rocket accelerated away you would see the photons slowly red shifting. But you could not be "scratching your head about who/what was pushing your rocket" until it reached the speed of light which would be never. Instead you would be scratching your head wondering what vaporized the asteroid behind you. Hint: the photons didn't just disappear. A photon rocket has an exhaust that is hotter and more destructive than any other kind of rocket giving the same thrust.
If I pretend that the EmDrive is a photon rocket, for which the thrust F = P/c, then the value of k in N/W = 1/c = 3.3 10-9 N/W. That is at least 3 orders smaller than the experimentally determined values of k that we've seen. And yet you wish to model the EmDrive as a diluted form (in some sense I do not understand) of a photon rocket? That would seem to imply a k value lower than 1/c, but in fact we see a higher one.
I can't bring myself to agree.
And about this "exhaust hole" of yours: this implies that the placement of the hole (or the waveguide power feed, you assert) must align with the resultant thrust vector. But experiment shows that this is not the case.
Again, I cannot agree with you.
What you are describing is just red shift. I think. It is very confused.
In an ordinary rocket the propellent has no momentum with respect to the rockets reference frame. You burn it and give it a huge momentum with respect to the rockets reference frame. In reaction the rocket gets a huge momentum in the other direction. In the original reference frame they both have huge momentum gain in opposit directions. That is how conservation of momentum works.
A photon rocket is not much different. A photon has some amount of momentum despite being massless. As the photon rocket accelerated away you would see the photons slowly red shifting. But you could not be "scratching your head about who/what was pushing your rocket" until it reached the speed of light which would be never. Instead you would be scratching your head wondering what vaporized the asteroid behind you. Hint: the photons didn't just disappear. A photon rocket has an exhaust that is hotter and more destructive than any other kind of rocket giving the same thrust.
But I'm not talking about light that the rocket-rider would see, I'm talking about light that the guy back on the launchpad would see. The launchpad guy would see the photon exhaust as red-shifted for a different reason, which is that the photons would have transferred some of their energy (momentum) to the rocket - ie. those photons are coming out of the rocket with lower energy than what they had when they were originally created inside the cavity. That's not really a red-shift.
Hmm, so let me maybe replace the photon rocket idea with a solar sail.
So you've got a solar sail that is moving because photons are hitting it. But what if your photon source isn't some external sun/star, but is actually sitting onboard the ship attached to the solar sail? Then it sounds like you can't generate any net thrust, since whatever momentum your photons transfer to the sail is offset by the momentum that was lost when the photons popped out of your onboard emitter.
But suppose your sail could experience multiple collisions with each photon that came out of the emitter? So that's the waveguide that's allowing this to happen. And each of those collisions is transferring some momentum. So the sum total of all momentum that a photon can transfer to the waveguide can't exceed the original momentum of the photon when you first produced/emitted it. So net thrust is zero because of the anti-thrust from producing the original photon.
Hmm, so now it doesn't work again...
I better go ask GoatGuy. :P
As far as I can tell, I am not the only one to have thought to a general relativity effect here. This paper (http://arxiv.org/abs/1302.5690) uses a modified version of Einstein equations to explain what is going on in a conical resonant cavity without violating momentum conservation. The point is that the author uses a weak perturbation approximation and I do not know if this is fully justified.
I had read that paper. Unfortunately, as the author of the paper states:QuoteThe weakest part of the theory seems to be that there is no clear way of preventing large gravitational effects due to the magnetic field of the Earth, as predicted by Eq. (17)
Therefore the author himself admits that his model is contradicted by predicting large gravitational effects due to the Earth's magnetic field that are contrary to all experimental evidence.
Multiple reflections of a photon help nothing.Yeah. Because most of us are completely sure that newtons law are correct, the only way that EMDrive and similar devices could work is transferring momentum. What, where and how are the questions.
The most important point to be made, is that to measure force, the cavity must
experience acceleration. In a fully restrained cavity, thrust and reaction force
cancel out.
This situation is unique to a propellantless thruster such as EmDrive and analogies
with conventional devices are pointless.
It therefore appears that a force measurement can only be made in a dynamic
environment, ideally by allowing the thruster to accelerate, measuring that
acceleration, and then calculating the thrust from T = -Ma
Multiple reflections of a photon help nothing.Yeah. Because most of us are completely sure that newtons law are correct, the only way that EMDrive and similar devices could work is transferring momentum. What, where and how are the questions.
It must be something different to photons and it must exists before, because push photons will mean less pushing for this energy.
White talk about virtual particles. I thing that the form could be more exotic. Something like a partially stable perturbation of quantum vacuum. Something like a vortex in a fluid but in quantum form, like a field not locally binded to a particle.
Whatever it was, it must carry energy by itself so push it carries more momentum that pure photons.
If a photon is like a fish in water, these unknown "momentum carriers" must be like walls in water. It must push vacuum energy, so it carries more momentum in the same way as you push more mass for the same energy.
Could we perhaps view a resonating EM wave cavity as a means to dynamically 'synthesize' or evoke 'exotic matter' ?I think that the term "momentum carrier" is a good name for something that we really don't know.
Multiple reflections of a photon help nothing.Yeah. Because most of us are completely sure that newtons law are correct, the only way that EMDrive and similar devices could work is transferring momentum. What, where and how are the questions.
It must be something different to photons and it must exists before, because push photons will mean less pushing for this energy.
Hmm, so let me maybe replace the photon rocket idea with a solar sail.
So you've got a solar sail that is moving because photons are hitting it. But what if your photon source isn't some external sun/star, but is actually sitting onboard the ship attached to the solar sail? Then it sounds like you can't generate any net thrust, since whatever momentum your photons transfer to the sail is offset by the momentum that was lost when the photons popped out of your onboard emitter.
But suppose your sail could experience multiple collisions with each photon that came out of the emitter? So that's the waveguide that's allowing this to happen. And each of those collisions is transferring some momentum. So the sum total of all momentum that a photon can transfer to the waveguide can't exceed the original momentum of the photon when you first produced/emitted it. So net thrust is zero because of the anti-thrust from producing the original photon.
Hmm, so now it doesn't work again...
I better go ask GoatGuy. :P
Pulse phasing discussed here:A interesting idea. That the EMDrive could be something like a "momentum capacitator", in form of photons inside the cavity. That must be accounted accurately, because is a good source of errors.
Pulse phasing discussed here:A interesting idea. That the EMDrive could be something like a "momentum capacitator", in form of photons inside the cavity. That must be accounted accurately, because is a good source of errors.
http://s000.tinyupload.com/index.php?file_id=05426775513544255924
Momentum could be "transfered" in time. A lot of photons are accumulated inside and when the walls of EMDrive change the temperature, the light reflect more than before, making do absorbed at different rates on different walls of the EMDrive making the net momentum accumulated in the photons.
But if the photons are accumulated on some time and released on less time and measured in this smaller time window, the force could be accounted greater than really are.
This hypotesis would require a "charging time" on the EMDrive before the measurement.
So you've got a solar sail that is moving because photons are hitting it. But what if your photon source isn't some external sun/star, but is actually sitting onboard the ship attached to the solar sail? Then it sounds like you can't generate any net thrust, since whatever momentum your photons transfer to the sail is offset by the momentum that was lost when the photons popped out of your onboard emitter.If the sail is reflective then it delivers twice the momentum of when the photon was initially released. Think of it like a baseball. When someone throws it and another catches it, the actions cancel. This is like absorbing the photon. If the catcher throws it back again as well (reflection) this is like a whole new throw. Luckily due to conservation of momentum we need not worry about the details, we can just look at before and after.
The ball is not caught and thrown back. Instead it bounces off the catcher's glove, transferring to it the momentum gained from the 1st thrower. So no overall momentum gain.So you've got a solar sail that is moving because photons are hitting it. But what if your photon source isn't some external sun/star, but is actually sitting onboard the ship attached to the solar sail? Then it sounds like you can't generate any net thrust, since whatever momentum your photons transfer to the sail is offset by the momentum that was lost when the photons popped out of your onboard emitter.If the sail is reflective then it delivers twice the momentum of when the photon was initially released. Think of it like a baseball. When someone throws it and another catches it, the actions cancel. This is like absorbing the photon. If the catcher throws it back again as well (reflection) this is like a whole new throw. Luckily due to conservation of momentum we need not worry about the details, we can just look at before and after.
So here's a theory, such as it is. The EM waves are 'cut' and 'squeezed' by the shape of the vessel.It does look a bit like a juicer ;)
Regarding the main controller parameter for the EM DriveThought Paul's latest pathway was to duplicate the 1st Shawyer teeter-totter test rig and blast away with a wide band magnetron and waveguide to feed the cavity. Hope they add the ability to manually adjust / tune the cavity length as Shawyer did before he went to an active feedback loop to lock the narrow band RF to the cavity resonance in the curved end plates Flight Thruster.
It is my understanding, from what Paul March wrote, that the main controlling parameter in determining the thrust generation performance of the EM-Drive is the rate of phase modulation of the RF signal that is injected into the resonant cavity.
This requires an FM modulated signal of around 100 kHz deviation that dithers back and forth around the resonant cavity's resonant frequency as fast as possible.
One has to feed the cavity through a 2 foot long RG-8 cable with Type-N connectors with the other end of this coax connected to a 3-Stub tuner that is used to set the 50 ohm Smith Chart Z-matching circle to an impedance solution that matches the 50 ohm load AND generates the narrowest +/-90 degree capacitive to inductive reactive phase change bandwidth in the cavity. This phase change bandwidth needs to be 10 kHz or less and preferable less than 4 kHz.
This information is useful to correctly and consistently tune an EM-drive prototype for maximum thrust.
If anybody has a different understanding of what he wrote, it would be useful to know.
My understanding was that he could set the match to obtain the maximum phase change across the resonance line. This would give him the maximum effective Q. The FM dither would be a means of following the resonance. Back when, I used a double balanced modulator to find the 2 half-power points as the most accurate way to identify the center frequency. (but I didn't need a carrier there, I was measuring linewidth) AM or FM can be used the same way and in these cases you have power at the center of the resonance.Was this with or without a dielectric inside the cavity?
Like most here I'm fascinated and intrigued. However, I'm terrible at this type of math and better at making things. The device seems kind of simple on the surface, but I must assume I'm missing something (many things).How about some open source design? openscad (http://www.openscad.org/) has been mentioned before. We could put the STL files on the wiki (http://emdrive.echothis.com/index.php/Main_Page).
Have any science hobbyists built their own machine yet? I can't imagine that only three people have done this so far, and I'm working with a peer to design our own and build it this summer.
I'm still reading and re-reading this thread, and I'm not too many pages into it. So if someone has posted their experiments I'm sure I'll run across them sooner or later, but if anyone knows of any build logs or hobbyists making a drive I'd love to see what they did and how it worked.
I do have a question for those who may know, what do you think is the biggest hurdle to building a functioning EM Drive?
Like most here I'm fascinated and intrigued. However, I'm terrible at this type of math and better at making things. The device seems kind of simple on the surface, but I must assume I'm missing something (many things).DO NOT reinvent the wheel.
Have any science hobbyists built their own machine yet? I can't imagine that only three people have done this so far, and I'm working with a peer to design our own and build it this summer.
I'm still reading and re-reading this thread, and I'm not too many pages into it. So if someone has posted their experiments I'm sure I'll run across them sooner or later, but if anyone knows of any build logs or hobbyists making a drive I'd love to see what they did and how it worked.
I do have a question for those who may know, what do you think is the biggest hurdle to building a functioning EM Drive?
...Funding. :(
I do have a question for those who may know, what do you think is the biggest hurdle to building a functioning EM Drive?
Could add Mulletron's GDrive:Like most here I'm fascinated and intrigued. However, I'm terrible at this type of math and better at making things. The device seems kind of simple on the surface, but I must assume I'm missing something (many things).How about some open source design? openscad (http://www.openscad.org/) has been mentioned before. We could put the STL files on the wiki (http://emdrive.echothis.com/index.php/Main_Page).
Have any science hobbyists built their own machine yet? I can't imagine that only three people have done this so far, and I'm working with a peer to design our own and build it this summer.
I'm still reading and re-reading this thread, and I'm not too many pages into it. So if someone has posted their experiments I'm sure I'll run across them sooner or later, but if anyone knows of any build logs or hobbyists making a drive I'd love to see what they did and how it worked.
I do have a question for those who may know, what do you think is the biggest hurdle to building a functioning EM Drive?
My budget is $500. Should be enough but I have a good workshop & cabinet load of electronics. Plus a lot of self build & many hours of blood, sweat and tears....Funding. :(
I do have a question for those who may know, what do you think is the biggest hurdle to building a functioning EM Drive?
...
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
I'm an engineer that designs, builds, commissions & teaches others how to maintain what I designed and built, while being very willing to pick up a tool bag and get grease up to my arm pits to get things back working and into service....
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
Did Shawyer send the paper by Cullen by mistake, and he meant to send another paper instead to support his theory?
Do you know of any paper supporting Shawyer's theoretical model ?
I'm an engineer that designs, builds, commissions & teaches others how to maintain what I designed and built, while being very willing to pick up a tool bag and get grease up to my arm pits to get things back working and into service....
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
I look at tests of stuff that are claimed to work. If they pass my gut test, I may used them to guide my replication and test process. I try to limit reinventing the wheel.
Everything I read from Shawyer about how the devices interact with / work in the physical world, supports his many & various claims & statements & builds a strong model that they do indeed work.
To settle the matter if the EM Drive works or not, for me, demands that I do a replication, as close to the work Shawyer has done as possible. Which is what I'm planning to do.
OK, here is one practical thing that researchers can adopt, based on Cullen's paper (and 140 years since Maxwell, with people trying to perform experimental measurements of radiation pressure, which are plagued by air convection currents), to avoid getting false data:Thanks for the feedback.
It was impossible to obtain a stable baseline, even on a relatively short-term basis of a minute's duration. This continual drifting of the baseline was found to be due to air convection currents set up by small and changing temperature gradients within the microwave waveguides. The remedy was to reduce the air resistance of the reflecting end plate so that the convection currents would have no appreciable effect. The reflecting end plate was replaced by a system of concentric wire rings (shown on Fig. 12 of Cullen's paper). The rings acted as an almost perfect reflector of the electromagnetic waves but at the same time had a small effective cross-section to air currents. NASA, Shawyer, Yang, and other EM Drive researchers would be well advised to experiment with replacing the end plates of the EM Drive with this system of concentric rings, in order to address the problem of air convection currents that has plagued radiation pressure experiments in ambient conditions ever since Maxwell 140 years ago.
.....
Please see the following reference (https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583, click "Get PDF" to download the paper for free):
It is shown that all modes run continuously from travelling waves through a transition to an evanescent (exponentially decaying) wave region and the value of the attenuation increases as they approach the cone vertex.
A strict distinction between pure travelling waves and pure evanescent (exponentially decaying) waves cannot be achieved for conical waveguide.
One mode after the other reaches cutoff in the tapered hollow metallic waveguide as they approach the cone vertex.
.....
Thank you Dr. Rodal for a very informative post!
I've been studying the reference you provided, to Zeng and Fan. You cannot imagine how coincidental it is, but sometimes the universe works that way. Their equations 8 thru 11, are simple enough to understand without too much difficulty. These are "effectively" the same equations that govern gravity in the Engineering model of GR I work with, which is based on the PV Model. Gravity, as a refractive index, appears as the Damping function that governs the attenuation of the wave functions, and the ZPF acts as the Driving function that keeps it all afloat at "our" relative vacuum energy level. The two are in equilibrium, in what QED calls the fluctuation-dissipation relationship, and gravity is the asymmetry between the two that occurs wherever you have matter that filters the modes. It's pretty simple and intuitive to understand, but nobody seems to get it.
You asked about the truncated cones. From an engineering perspective, if it is not truncated it will have a difficult time resonating at any mode. The convex-concave end plates would seem to be necessary to maximize energy storage as spherical harmonics. So then, what modes do we want to attenuate? That would depend on what modes we can inject that will sustain resonance. It won't resonate when the angle is increased too much, but if we have attenuation factor equations from this paper, then I believe it can be modeled.
Getting back to the paper, based on their graphs for attenuation, it would seem a small angle is preferred. A large angle approximates a flat plate. Anything greater than pi/6 is not much better than bouncing photons off of a flat plate. However, for theta = pi/24, the attenuation is very high at much shorter wavelengths, and very high at longer wavelengths. It needs to strike a balance between energy storage and thrust at the modes available to us.
Again, gravity acts on the wave functions through the metric, transforming the (E,p) 4-vector. The metric is a refractive index. The effect on the wave function is equivalent to a Damping factor, in the damped harmonic oscillator equation. I see the attenuation factor in their plots as "similar" to that effect, acting on the microwaves in the cavity near the cut-offs. As the waves are attenuated, their momentum is absorbed as wave velocity goes to zero, just like light falling into a black hole. The result is propulsion. The bonus is that in such a space-time where the speed of light is variable, momentum conservation is dependent on the group velocity. It's not Newtonian anymore, because velocity is not a constant.
The light is being squeezed by the slowing of the group velocity, and since Energy is conserved, momentum must increase to compensate for reduced wave velocity. Another way to look at it is, photons in the waveguide "gain" an "effective mass".
I see a lot of people arguing over photon rockets, despite the evidence that the thrust is orders of magnitude larger. No rocket nozzle is going to change that as long as the speed of light is considered to be constant, even if it captured all the energy from all the reflections produced. In order to get the thrust values they are seeing you must consider the reduction in wave velocity inside the waveguide, and that attenuation is asymmetrical, just like it is in a gravitational field.
Thanks again, for some very interesting new information.
Best Regards,
Todd D.
Getting back to the paper, based on their graphs for attenuation, it would seem a small angle is preferred. A large angle approximates a flat plate. Anything greater than pi/6 is not much better than bouncing photons off of a flat plate. However, for theta = pi/24, the attenuation is very high at much shorter wavelengths, and very high at longer wavelengths. It needs to strike a balance between energy storage and thrust at the modes available to us.
I see the attenuation factor in their plots as "similar" to that effect, acting on the microwaves in the cavity near the cut-offs. As the waves are attenuated, their momentum is absorbed as wave velocity goes to zero, just like light falling into a black hole. The result is propulsion.
...
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
...
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
The conclusions of Egan are correct when only considering radiation pressure at wavelength's that are short compared to the cut-off modes. They are incorrect because he did not take into consideration the variable speed of light inside the waveguide for wavelengths close to the cut-off modes. He used eps0 and mu0 as the permittivity and permeability of free vacuum in all his calculations of energy density and force. That is an error!
The space inside the waveguide is not free vacuum, it is constrained by the waveguide. Near the cut-ff modes, his calculations are invalidated because the speed of light is not the same throughout the cavity.
Best Regards,
Todd D.
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
I did read your review that there should be no thrust. But there seems to be thrust, of a level and direction which agrees with Shawyer's theory. Which is why the Shawyer and Chinese thrust claims need to be experimentally verified or not....
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
I did read your review that there should be no thrust. But there seems to be thrust, of a level and direction which agrees with Shawyer's theory. Which is why the Shawyer and Chinese thrust claims need to be experimentally verified or not....
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
I believe there is enough data in the public domain to experimentally replicate their test setups, cavity designs and RF generation / feed methods, starting with the RF narrow band, spherical end plate Flight Thruster, feed via coax, which I plan to replicate in copper and if necessary in Alumininum.
...
Out of interest have any of Eagleworks results appeared on arXiv?I saw that in the article. I didn't bother to check because anyone can publish anything on arXiv:
I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
<snip>
The conclusions of Egan are correct when only considering radiation pressure at wavelength's that are short compared to the cut-off modes. They are incorrect because he did not take into consideration the variable speed of light inside the waveguide for wavelengths close to the cut-off modes. He used eps0 and mu0 as the permittivity and permeability of free vacuum in all his calculations of energy density and force. That is an error!
The space inside the waveguide is not free vacuum, it is constrained by the waveguide. Near the cut-ff modes, his calculations are invalidated because the speed of light is not the same throughout the cavity.
Best Regards,
Todd D.
...The correct statement is that any solution solely based on Maxwell's equations (like Greg Egan's analysis) predicts no thrust, and that therefore the measurements at NASA Eagleworks are due to something else not addressed by Maxwell's equations.
Todd, your explanation uses General Relativity and the Quantum Vacuum, which are explicitly not addresed by Greg Egan. His solution is still mathematically exact (solution of Maxwell's equations), it may just not be representing the actual physical tests. Either because the tests are an artifact or because they represent some form of propulsion that may be explained by your model or other alternative models.
On the other hand what is mathematically incorrect would be to state that a solution solely based on Maxwell's equation and special relativity (without invoking GR, or the QV, or something else) can predict a thrust in a closed cavity: that is plainly mathematically incorrect. Something else is needed besides Maxwell's equations and special relativity.
I hope yours (or another theory) succeeds in explaining the measurements as something that can be used for space propulsion, or that it is an artifact. But the experimental measurements cannot be explained solely based on Maxwell's equations and special relativity.
:)
...
With respect, your theory.I did read your review that there should be no thrust. But there seems to be thrust, of a level and direction which agrees with Shawyer's theory. Which is why the Shawyer and Chinese thrust claims need to be experimentally verified or not....
DO NOT reinvent the wheel.
Follow Shawyer as close as you can.
Plenty of clues but you need to do a lot of reading.
....
You are writing that in reference to Shaywer's experiments, I presume, but a number of Shawyer's prescriptions are tied to his theoretical model. I read the paper that Shawyer sent to Mulletron, to support Shawyer's theoretical model.
I wrote a review of this paper here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
Showing that there is nothing in that paper (by Cullen) supporting Shawyer's theoretical model. On the contrary, it follows the same Maxwell's equations and laws followed by Greg Egan http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html who concludes that the EM Drive should have no thrust force.
I believe there is enough data in the public domain to experimentally replicate their test setups, cavity designs and RF generation / feed methods, starting with the RF narrow band, spherical end plate Flight Thruster, feed via coax, which I plan to replicate in copper and if necessary in Alumininum.
...
No, my review never states that there should be no thrust in the experimental results.
My review instead states (and shows, carefully, point by point) that the reference given by Shawyer to support his theoretical model, does NOT support his model at all.
Therefore I do not understand why Shawyer references Cullen's paper.
As a reductio ad absurdum, it would be almost like Shawyer referencing Greg Egan, and sending Greg Egan's analysis as support for Shawyer's theoretical explanation.
...
Let F1 and F2 be the Maxwell field tensor for each.
The force density;
f = J1*F2 - J2*F1 = 0 in flat space-time
It does not equal zero in curved space-time because there is a metric in each product, that has a different value in each location. Shawyer is right in this regard, but I'm no better at the covariant equations than he is.
Thank you!
Best Regards,
Todd
I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Ditto on the engineering years and seeing strange things. Been there, seen that.
Enjoyed reading the comments from Davis and Millis. More replication attempts to come. The race has begun. :)If we hang together and openly share info, we can make this happen.
...I think we (people reading this) can write the covariant equations. The equations would be nonlinear, and therefore an exact solution would prove impossible to obtain for the truncated cone. How would you proceed ? via a perturbation analysis (if so in terms of what dimensionless parameter?) or via a numerical solution?
It does not equal zero in curved space-time because there is a metric in each product, that has a different value in each location. Shawyer is right in this regard, but I'm no better at the covariant equations than he is.
...
...I think we (people reading this) can write the covariant equations. The equations would be nonlinear, and therefore an exact solution would prove impossible to obtain for the truncated cone. How would you proceed ? via a perturbation analysis (if so in terms of what dimensionless parameter?) or via a numerical solution?
It does not equal zero in curved space-time because there is a metric in each product, that has a different value in each location. Shawyer is right in this regard, but I'm no better at the covariant equations than he is.
...
EDT : I think the motivation would increase if there would be an answer to the energy paradox (what restricts the energy paradox for constant acceleration at constant power ?)
OK, I agree with what you state above....I think we (people reading this) can write the covariant equations. The equations would be nonlinear, and therefore an exact solution would prove impossible to obtain for the truncated cone. How would you proceed ? via a perturbation analysis (if so in terms of what dimensionless parameter?) or via a numerical solution?
It does not equal zero in curved space-time because there is a metric in each product, that has a different value in each location. Shawyer is right in this regard, but I'm no better at the covariant equations than he is.
...
EDT : I think the motivation would increase if there would be an answer to the energy paradox (what restricts the energy paradox for constant acceleration at constant power ?)
The non-linear set of Einstein-Maxwell equations has exact solutions for plane waves. You can apply it to a schematic of a laser beam transiting in a cavity having the form of a cube without difficulty. A plane wave always deforms space-time and a cavity has the advantage that the energy of the field depends also on the Q factor that can increase it by orders of magnitude. This means that an explanation for the question of the behaviour of the laser beam inside the cavity can be easily at hand. For the other question, the thrust, as a physicist I keep on being rather sceptical because I tried to move my car by hitting the windscreen with punches and nothing happened.
I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
StrongGR may be talking about a closed-form solution for that case (without the dielectric insert), therefore a mathematical formula. Not necessarily including plots, as they are necessary for numerical solutions.I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
May I respectfully ask that you also include a visualization of the solution if possible? I'd very much like to see this.
Enjoyed reading the comments from Davis and Millis. More replication attempts to come. The race has begun. :)
...I think we (people reading this) can write the covariant equations. The equations would be nonlinear, and therefore an exact solution would prove impossible to obtain for the truncated cone. How would you proceed ? via a perturbation analysis (if so in terms of what dimensionless parameter?) or via a numerical solution?
It does not equal zero in curved space-time because there is a metric in each product, that has a different value in each location. Shawyer is right in this regard, but I'm no better at the covariant equations than he is.
...
EDIT :1) I think the motivation would increase if there would be an answer to the energy paradox (what restricts the energy paradox for constant acceleration at constant power ?)
and this also needs to be addressed:
2) Regarding the force summation by Shawyer, what happened to the force vector components on the lateral, conical surfaces? Why is it that only the forces on the end plates (the bases of the truncated cone) are being addressed? If one includes the forces on the lateral conical surfaces everything sums to zero (solely using Maxwell's equations)
That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
Regarding the energy paradox.
Power = Force * Velocity
Acceleration = Force / Mass = Power / Momentum
Therefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something.
Best Regards,
Todd D.
That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.
Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
Rodal: " Their results could be due to outgassing from FRP4"
This is some sort of fibreglass?
Rodal: " Their results could be due to outgassing from FRP4"
This is some sort of fibreglass?
Would be interested in testing that idea. AFTER either no thrust or thrust is found.That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.
Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
Thermal buckling is extremely dependent on initial imperfections, thus it is highly unlikely that it can be the only explanation for multiple tests at multiple locations with multiple specimens.
Therefore something else is at play here.
Pressure measurements due to radiation have been plagued with air convection currents for 140 years.
None of the experimenters have used the proper test set-up in ambient conditions: nobody has used concentric rings (see this http://forum.nasaspaceflight.com/index.php?topic=36313.msg1370479#msg1370479 )
Only NASA Eagleworks is the only one that has conducted tests in a vacuum. Their results could be due to outgassing from the fiberglass-reinforced-epoxy end-plate.
Therefore I highly advise that they should replace the end plates with concentric rings to rule out false positives, as done by Cullen in 1951, the first person to accurately measure microwave radiation pressure from microwaves.
But what if... lets assume the theory of the thrusting of virtual particles. What if they also were able to tunnel and end up outside the cavity before they do whatever they normally do?Question to all:Yes, we considered it. It would become an inefficient photon rocket, as only a few of the photons would tunnel and the beam would not be perfectly collimated. Hence it would not explain a claimed thrust/PoweInput thousands of times greater than a perfectly collimated photon rocket.
Has quantum tunneling been incorporated in any calculations? I read once that at least some photons will tunnel through the medium of the cavity walls. Hope this sparks something in someone's mind.
That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.
Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.
Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
I'm slowly digging through the nice thermal expansion write-up, nice work. I was wondering if you have an IR camera and pics to back your calculations, as I'd like to see the thermal increases not only on the endcap but on the sides of the EM chamber. Thanks Guys!
Regarding the energy paradox.
Power = Force * Velocity
Acceleration = Force / Mass = Power / Momentum
Therefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something.
Best Regards,
Todd D.
No. You are conflating input power and output power here. Please see my analysis.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875
The EmDrive is not a tyre and spacetime is not the road upon which it rides.
If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.
Regarding the energy paradox.
Power = Force * Velocity
Acceleration = Force / Mass = Power / Momentum
Therefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something.
Best Regards,
Todd D.
No. You are conflating input power and output power here. Please see my analysis.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875
The EmDrive is not a tyre and spacetime is not the road upon which it rides.
If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.
Special Relativity does not apply to accelerating reference frames, which is what is being described here. Accelerated reference frames "are" preferred frames because they can be distinguished from one another, unlike inertial frames.
If F = P*k
Then the work done is the integral;
W = integral[Pin*k*v]*dt from t=0 to t2.
Pout = dW/dt = Pin*k*v
Since Pin = Pout, k = 1/v
The Power in will equal the Power out, the Work done will be the integration of Force * distance. Acceleration is not constant with constant Power input.
I have a hunch that there is a hidden assumption in your derivation that acceleration is constant, so you get over-unity results.
This needs to be considered like a Power Transformer. Power in = Power out.
That's my 2 cents worth.
Todd D.
Regarding the energy paradox.
Power = Force * Velocity
Acceleration = Force / Mass = Power / Momentum
Therefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something.
Best Regards,
Todd D.
No. You are conflating input power and output power here. Please see my analysis.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875
The EmDrive is not a tyre and spacetime is not the road upon which it rides.
If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.
Special Relativity does not apply to accelerating reference frames, which is what is being described here. Accelerated reference frames "are" preferred frames because they can be distinguished from one another, unlike inertial frames.
If F = P*k
Then the work done is the integral;
W = integral[Pin*k*v]*dt from t=0 to t2.
Pout = dW/dt = Pin*k*v, Since Pin = Pout, k = 1/v.
The Power in will equal the Power out, the Work done will be the integration of Force * distance. Acceleration is not constant with constant Power input. I have a hunch that there is a hidden assumption in your derivation that acceleration is constant, so you get over-unity results. This needs to be considered like a Power Transformer. Power in = Power out.
That's my 2 cents worth.
Todd D.
That's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Yes, see this analysis by one of the people in this forum:
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.
Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
I'm slowly digging through the nice thermal expansion write-up, nice work. I was wondering if you have an IR camera and pics to back your calculations, as I'd like to see the thermal increases not only on the endcap but on the sides of the EM chamber. Thanks Guys!
These are the thermal measurements vs. thermal and electromagnetic field analysis (COMSOL FEA) for NASA Eagleworks for the experiments in a partial vacuum ;) :
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634723
The thermal distribution is clearly due to induction heating from the magnetic field, as expected.
My exact solution (elsewhere in other posts) for the magnetic field, for the electric field, confirms that the numerical solution using COMSOL FEA is within 1% of the exact solution, they used a good finite element mesh discretization and the numerical solution is practically converged to the exact result.
Also Prof. Juan Yang's reported temperature vs. time measurements with embedded thermocouples throughout their EM Drive cavity (without a polymer dielectric insert) under atmospheric conditions, that, curiously, show the highest temperature at the center of the small base (trace #1), followed, at a significantly lower temperature by the temperature at the periphery of the big base (trace #5).
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=622845;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=655009;image)
Notice how much higher temperature is present in the Chinese (Yang) experiments.
Shawyer has not reported graphical information on thermal measurements for his experiments, to my knowledge.
I suspect same problem for Shawyer's experiments: huge thermal effects for Yang and Shawyer.
Also, tan delta out-of-phase losses in these cavities are not zero,particularly in NASA's dielectric polymer insert: the reported experiments show that the tan delta values of the materials used in these cavities is consistent with real materials experiencing out-of-phase dissipation (therefore one must use the complex form of the physical properties and not neglect the imaginary part if one is interested in assessing the finite value of Q, for example).
....
Thank You for taking your time to answer me! I've got a little to digest here, but there is more than enough.
Is there any reason no one has used a simple copper mesh for the EM chamber?
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
This condition occurs at a change in time of which equates to a. When this
situation occurs, in order to ensure that the input energy is
equal to the change in kinetic energy, the thrust to power
performance will have to decrease over time. This scenario
has an analog in the terrestrial realm when considering
a turbine aircraft flight profile. At takeoff, the turbine
aircraft has a very high thrust to power (hundreds of
N/kW), but at cruise altitude, the thrust to power performance
is much lower (1-10 N/kW). The following graph
shows the curve with some highlighted data points for
consideration.
I must reject the analysis by J & W in Appendix A, but thanks for the link.
I have already mentioned in my preamble that not only is any propellantless propulsion craft capable of perpetuum mobile operation, but that free energy is available on top of that to boot.
This causes many people to break out in hives, or to resort to chewing their towels. ::)
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
deltaMass, can you explain this further?
With my limited SR understanding - the statement "x knows what speed it's going and adjusts the thrust" seems perfectly acceptable to me (minus the word "thrust") but I realize I'm likely missing some key points. If you have two star systems and a rocket sets out for the other at the speed of light (99.999 etc) from each star system toward each other. Is the speed of the two rockets approaching each other 2c? No. Does that mean the two dropped down to .5c? No. Are they "aware" of each other? Kinda. If they decide to burn their thrusters a max does their approach speed increase? No.
I realize you probably already understand this or maybe my understanding is wrong - so what am I missing?
Thank you for your help!
I must reject the analysis by J & W in Appendix A, but thanks for the link.
I have already mentioned in my preamble that not only is any propellantless propulsion craft capable of perpetuum mobile operation, but that free energy is available on top of that to boot.
This causes many people to break out in hives, or to resort to chewing their towels. ::)
We can of course test to see this at work. We use a rotary configuration and when the tangential velocity exceeds 2/k, we switch from external power to a coaxially mounted generator. And then begin charging people for the juice. Outrageous! 8)
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
I think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
To your first sentence:I must reject the analysis by J & W in Appendix A, but thanks for the link.
I have already mentioned in my preamble that not only is any propellantless propulsion craft capable of perpetuum mobile operation, but that free energy is available on top of that to boot.
This causes many people to break out in hives, or to resort to chewing their towels. ::)
We can of course test to see this at work. We use a rotary configuration and when the tangential velocity exceeds 2/k, we switch from external power to a coaxially mounted generator. And then begin charging people for the juice. Outrageous! 8)
I would think the free energy speculation is a bit premature. The "frame of reference problem" could inhibit any constrained mechanism, not that such can be calculated until the momentum question is resolved.
Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
To your first sentence:I must reject the analysis by J & W in Appendix A, but thanks for the link.
I have already mentioned in my preamble that not only is any propellantless propulsion craft capable of perpetuum mobile operation, but that free energy is available on top of that to boot.
This causes many people to break out in hives, or to resort to chewing their towels. ::)
We can of course test to see this at work. We use a rotary configuration and when the tangential velocity exceeds 2/k, we switch from external power to a coaxially mounted generator. And then begin charging people for the juice. Outrageous! 8)
I would think the free energy speculation is a bit premature. The "frame of reference problem" could inhibit any constrained mechanism, not that such can be calculated until the momentum question is resolved.
If by that you mean the engineering issues, then I couldn't agree more, and have already estimated here the performance gap which exists. Feel free to run your own numbers; I reckon currently we're about a factor of 50 down on breakeven.
But if by that you mean the physics, I must needs take issue. Have you looked at string theory lately? 8)
I'm sorry, but I don't really understand your second sentence. Perhaps you could say it another way?
My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Once the cavity is constrained into some fixture that ties it to a fixed frame of reference we become dependent on the type of mechanism (and it's GR behavior) which is responsible for the change in momentum of the cavity.Indeed. I was limiting my discussion to a device freely moving under its own power in free space. Clearly, bolting it down to a lab vac chamber does not satisfy that criterion.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Are you really saying that you reject this?
Quote from: NotsosureofitOnce the cavity is constrained into some fixture that ties it to a fixed frame of reference we become dependent on the type of mechanism (and it's GR behavior) which is responsible for the change in momentum of the cavity.Indeed. I was limiting my discussion to a device freely moving under its own power in free space. Clearly, bolting it down to a lab vac chamber does not satisfy that criterion.
I trust you appreciate how I've "black boxed" propellantless propulsion devices - any and all of them. What I've said doesn't depend on what kind of device it is, nor upon any particular pet theory used to explain its "propellantlessness".
My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Are you really saying that you reject this?
I'm sorry, but I can only entertain a further discussion if we restrict ourselves to severely subrelativistic (i.e. slow) scenarios - since that is a constraint I've imposed upon myself for the purposes of the most elementary possible discussion of the dynamics.
In that framework then, and assuming (to first order, of course) a flat spacetime, do you now agree with Einstein's assertion about physics in inertial frames?
When matter is accelerated, length contracts and time dilates, this is a scale transformation. When the thrust is turned off and the coasting rocket finds itself is at rest relative to some distant planet. It's length does not spring back to "normal" and the clock does not speed up. They remain in this relative state until thrust is reversed and they return to the same vacuum energy state they started from.
My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Are you really saying that you reject this?
What about with respect to the "Cosmic Microwave Background Radiation" CMBR? Couldn't we say the universe has this as an absolute frame?
https://scholar.google.com/scholar?cluster=16121186223305818545&hl=en&as_sdt=0,48
Lets say there is a God view looking above far from all gravitational fields observing the universe and stationary with respect to its boundaries. (It should have a finite size if it had a beginning and an expansion.) Light falling into gravity fields I would think should slow down, (considering the limit when light reaches an event horizon). From inside a gravity field I should think light should still appear to be going c due the shrinking of the ruller. This could give the appearance of the index of refraction (gravitational lensing). Two objects traveling towards each other @ .6c still appear from the God view to be approaching at 1.2c though I suppose the two observers both have their (space/time) warped so it appears to them they are not approaching each other at 1.2c but rather v<c. I mean sure time/space screws our perceptions all up but why not have an absolute frame of the universe or CMB where either we are moving with respect to it or we arent? Or am I missing something.
When matter is accelerated, length contracts and time dilates, this is a scale transformation. When the thrust is turned off and the coasting rocket finds itself is at rest relative to some distant planet. It's length does not spring back to "normal" and the clock does not speed up. They remain in this relative state until thrust is reversed and they return to the same vacuum energy state they started from.
WarpTech,
From my understanding the length contraction and time dialation (warping of space-time) is based on velocity. From the perspective of point A, if a rocket zooms past it at constant velocity it will display the warped effect. Lets say Planet B already matches the direction and velocity of the rocket and the rocket slows down relative to planet A. Planet B would see the time dilation and length contraction start to change and that change would stop when deceleration of the rocket stops relative to planet A (at the same time - it is also accelerating away from planet B).
It is my personal feeling, and not something I've read nor can quantify - that acceleration has a sort of friction against space-time because it needs to bend it. The EM Drive (if it works) bypasses this by spending it's energy on bending space-time rather than accelerating matter. It is in essence falling. I believe you are proving this but I may be wrong.
The only way I can explain this away is that the EM Drive creates two gravity wells with the same energy level on both sides. The rear one is tightly focused and deep and the front one is broad and weak. Both are centered within the frustum near the ends. The reason there is motion is due to the larger/weaker gravity well extending beyond the bounds of the frustum more prominently in the front than the rear. The rear well would be spending most of it's energy tugging at the walls of the frustum. I cannot prove any of this so please consider it food for thought.
I love reading your posts, please keep up the great work!
Excellent. Then we are in complete agreement. Phew. Let's let this sink in for everyone else.I'm sorry, but I can only entertain a further discussion if we restrict ourselves to severely subrelativistic (i.e. slow) scenarios - since that is a constraint I've imposed upon myself for the purposes of the most elementary possible discussion of the dynamics.
In that framework then, and assuming (to first order, of course) a flat spacetime, do you now agree with Einstein's assertion about physics in inertial frames?
Okay then. If we are restricting ourselves to Newtonian mechanics, then we have a paradox that cannot be resolved. It leads to either an over-unity device or a preferred reference frame, and momentum is not conserved.
However, if we honestly want to resolve the paradox and conserve momentum, then we must use General Relativity to solve the problem, regardless of how fast it is going.
I'm sorry, that's just the way it is. There is no Newtonian resolution for this argument.
Thank you.
Todd
I brought this up in the other thread. In my mind the CMBR is our zero point for energy. Anything below it would look like negative energy from our frame of reference. Oddly enough, only the tests that had an odd harmonic close to 160200 MHz worked. I just believe that there is a "bingo frequency" that will make this thing go.My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Are you really saying that you reject this?
What about with respect to the "Cosmic Microwave Background Radiation" CMBR? Couldn't we say the universe has this as an absolute frame?
https://scholar.google.com/scholar?cluster=16121186223305818545&hl=en&as_sdt=0,48
Lets say there is a God view looking above far from all gravitational fields observing the universe and stationary with respect to its boundaries. (It should have a finite size if it had a beginning and an expansion.) Light falling into gravity fields I would think should slow down, (considering the limit when light reaches an event horizon). From inside a gravity field I should think light should still appear to be going c due the shrinking of the ruller. This could give the appearance of the index of refraction (gravitational lensing). Two objects traveling towards each other @ .6c still appear from the God view to be approaching at 1.2c though I suppose the two observers both have their (space/time) warped so it appears to them they are not approaching each other at 1.2c but rather v<c. I mean sure time/space screws our perceptions all up but why not have an absolute frame of the universe or CMB where either we are moving with respect to it or we arent? Or am I missing something.
http://arxiv.org/abs/physics/0306196
Inside the frustum, toward the large end is a reflector. Toward the small end, the taper is a high-pass filter. As waves are attenuated, they shift toward longer wavelengths and are cut-off by the dimensions of the waveguide. The cut-off is analogous to a black hole. The wave velocity goes to zero and that end of the frustum absorbs the momentum because it can't escape. There is only 1 gravity well inside it. That is in the direction of the lowest group velocity.
Inside the frustum, toward the large end is a reflector. Toward the small end, the taper is a high-pass filter. As waves are attenuated, they shift toward longer wavelengths and are cut-off by the dimensions of the waveguide. The cut-off is analogous to a black hole. The wave velocity goes to zero and that end of the frustum absorbs the momentum because it can't escape. There is only 1 gravity well inside it. That is in the direction of the lowest group velocity.
What perplexes me is that the latest improvements to Shawyer's design have been to optimize reflectivity. Which to me seems that the goal is to accumulate the energy within the frustum rather than trying to absorb the energy by capturing momentum. In your opinion - does one exclude the other?
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
Or you could also give the example of EM Drive ship 1 (which started from a different place) being overtaken by EM Drive ship 2 ...
EDIT:
See White and Joosten, Appendix :
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf
Hypothetically, if there were a black box with a gravitational field "inside", i.e., it has a NET acceleration vector along the X axis, pointing toward the blue side of the box..., (which is opposite the red side of the box) but has no discernible gravitational field "outside" of the box other than what a normal box of that mass would have. Let's say that inside the box there is all the equipment and energy storage, necessary to generate this field. Nothing comes in or goes out, but the energy stored inside it (battery) is being dissipated without being expelled.I must confess that I don't understand this system. It seems to suggest that a gravitational field can be generated at will de novo and also shielded. I wouldn't know where to start with something like that.
What sort of motion would YOU expect to see?
1. Will it move forward with the blue side leading?
2. Will it move forward with the red side leading?
3. Will it not move at all because nothing is coming out?
Keep in mind, by definition, it has a NET acceleration vector inside along the X axis.
Todd
Hi guys, on the theoretical side, has someone looked into this:
http://arxiv.org/abs/hep-th/0508246
Using strong external fields to modify locally a space-time
If my EM Drive experiment generates significant thrust, it will be time to move onto the next experiment which will answer the COE question.It is going to be a mechanical challenge! I wish you all the best though.
Plan is to build a rotary test device that drives a DC generator and it a variable load. Then can vary the load on the DC generator and observe changes in the energy delivered by the power supply to the RF amp versus energy consumed by the load. All data logged. Will draw a line in the sand about if an EM Drive obeys COE while it delivers energy to it's load.
Rotary test rig is not that hard or complex to build. Will be self powered with recharge Lithium batts as the counter balance and 2 way WiFi data links. No wires to worry about. So many really nice & inexpensive tools today.If my EM Drive experiment generates significant thrust, it will be time to move onto the next experiment which will answer the COE question.It is going to be a mechanical challenge! I wish you all the best though.
Plan is to build a rotary test device that drives a DC generator and it a variable load. Then can vary the load on the DC generator and observe changes in the energy delivered by the power supply to the RF amp versus energy consumed by the load. All data logged. Will draw a line in the sand about if an EM Drive obeys COE while it delivers energy to it's load.
And you are quite correct that such a rotary device can answer the CofE question without going all the way up to breakeven. It is a rotary version of the thought experiment I wrote about above. The principle of operation can be tested at quite low speeds. For some stupid brainfarty reason I had imagined that one had to go right up to breakeven speed.
If you believe Appendix A (and I hope you don't) then you do have to get up to breakeven and beyond, because of the strange knee function that is proposed there. It can't be like that.
The main attraction would be to get an EmDrive to accelerate a wheel from rest, period.Already been done.
That would be a Red Letter Day indeed - irrespective of the CofE issue.
That would be headline news.
Because of the coax RF feed I assume you'll mount the RF amp and any associated electronics next to the cavity?
The main attraction would be to get an EmDrive to accelerate a wheel from rest, period.Already been done.
That would be a Red Letter Day indeed - irrespective of the CofE issue.
That would be headline news.
Because of the coax RF feed I assume you'll mount the RF amp and any associated electronics next to the cavity?
http://emdrive.com/dynamictests.html
Watch the videos.
RF amp will be mounted next to the cavity but outside the Faraday Cage. If it leaks too much RF, will put it in it's own Faraday Cage.
Already been done.Not really. Large air bearings will give you their own thrust with the slightest imperfection or obstruction. A wheel is much cleaner and more believable.
http://emdrive.com/dynamictests.html
Watch the videos.
Point is Shawyer did a rotary test, did measurements & they confirmed COE observed.Already been done.Not really. Large air bearings will give you their own thrust with the slightest imperfection or obstruction. A wheel is much cleaner and believable.
http://emdrive.com/dynamictests.html
Watch the videos.
My tests will be streamed live via YouTube & recorded for all to watch over and over.The main attraction would be to get an EmDrive to accelerate a wheel from rest, period.Already been done.
That would be a Red Letter Day indeed - irrespective of the CofE issue.
That would be headline news.
Because of the coax RF feed I assume you'll mount the RF amp and any associated electronics next to the cavity?
http://emdrive.com/dynamictests.html
Watch the videos.
RF amp will be mounted next to the cavity but outside the Faraday Cage. If it leaks too much RF, will put it in it's own Faraday Cage.
The videos are nice, but until the mechanisms are replicated by an independent third party, it doesn't count for beans. Third party replication and verification is what makes the scientific method such a powerful tool. If the replication experiments are successful, then it'll be time to shout it from the rooftops. ;D
I disagree that they confirmed CofE observed. What was demonstrated was constant angular velocity at constant thrust. That represents zero acceleration. That does not correspond to either a constant acceleration model (non-CofE) nor to a decreasing acceleration model (CofE). What it shows is that an equilibrium was reached between the thrust and the friction at a particular angular velocity.Which is why I designed in an ability to be able to vary the mechanical load on the rotary test rig and observe changes in the amount of energy needed (increased RF power) to maintain a constant rate of angular motion. I plan to use magnetic bearings.
Friction is not our friend because it muddies the waters. It needs to be modelled and it dissipates power to boot. Basically, it complicates the analysis. Nevertheless, one is going to have to deal with it in the data analysis.
If it works, the Twitter verse will do the shouting.
Good comment.QuoteIf it works, the Twitter verse will do the shouting.
Really? As far as I can see, all you'll have proven is that a hot metal cone mounted on a turntable can create enough convection currents to move it around a bit :-\
Ensuring that the device is encased and no heat is getting out sounds very sensible, yes. :)Well heat always gets out. Insulation only slows down the rate of heat transfer.
I am not a math magician either, but when I read this, I picture "God" viewing it all from a higher spatial dimension, because that is the only way to properly overview 3D spacetime and be completele free of relativistic effects (example: we can oversee everything drawn on a sheet of paper which is one dimension lower than us, while a "flatlander" who lives in the paper cannot). That way "God" could create preferred frames at will. Or am I now talking BS?My mention of SR is simply in order to highlight a core principle of Einstein's thinking about space and time; to whit, there is no preferred inertial frame, such that physics there is different to physics in another one.Quote from: WarpTechI think I found the error in your analysis. You said,It is constant if and only if F is a constant of the motion. Which, as I have argued with recourse to SR, it indeed is.
v = a*t = (F/m)*t
This statement "assumes" acceleration is a constant. It is not a constant, so...
Did you find any other mistakes?
No, and I hear you. I believe energy is Force x Distance and Power in = Power out, and energy is conserved. I also believe SR is an "approximation" to a more accurate theory that includes the relative energy of the local quantum vacuum. That is how my model works, because that is how the Math in GR and QED tells us it should work.
Todd D.
Are you really saying that you reject this?
What about with respect to the "Cosmic Microwave Background Radiation" CMBR? Couldn't we say the universe has this as an absolute frame?
https://scholar.google.com/scholar?cluster=16121186223305818545&hl=en&as_sdt=0,48
Lets say there is a God view looking above far from all gravitational fields observing the universe and stationary with respect to its boundaries. (It should have a finite size if it had a beginning and an expansion.) Light falling into gravity fields I would think should slow down, (considering the limit when light reaches an event horizon). From inside a gravity field I should think light should still appear to be going c due the shrinking of the ruller. This could give the appearance of the index of refraction (gravitational lensing). Two objects traveling towards each other @ .6c still appear from the God view to be approaching at 1.2c though I suppose the two observers both have their (space/time) warped so it appears to them they are not approaching each other at 1.2c but rather v<c. I mean sure time/space screws our perceptions all up but why not have an absolute frame of the universe or CMB where either we are moving with respect to it or we arent? Or am I missing something.
Congratulations! You have just "correctly" described the Polarizable Vacuum Model of General Relativity. However, we do not need the CMBR. We simply define an observer "at infinity" to have a refractive index, K=1. From that perspective, he can observe the relative value of K, for all gravitational fields, where K > 1. If he sees something moving FTL, he will assign that space with a relative value of, K < 1.
It is still not a preferred frame, because K can be "defined" as 1 anywhere, and all observations are relative to that definition. Mark Millis has said that the CMBR is a preferred frame. IMO, it doesn't make the Math any easier, it just confuses people. As an engineer, I see all things as relative and take everything with a grain of salt. :)
Todd
Good comment.QuoteIf it works, the Twitter verse will do the shouting.
Really? As far as I can see, all you'll have proven is that a hot metal cone mounted on a turntable can create enough convection currents to move it around a bit :-\
Will add an IR camera video feed so we can see what the heat is doing. Could also put the EM Drive inside a 25mm thick foam box.
Are you OK with those changes eliminating any heat anomaly?
This dynamic test will only be done once the static tests show significant thrust and there is a input power to thrust curve available. This rotary test is not designed to measure thrust but to show how the power consumed by the EM Drive varies as rotary load varies, which to the EM Drive would be like a performance curve of power versus accelerative load mass.
Heh. Even when it's inside a sealed box?
That's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
That's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
Yes, my infrequent attempts at humour generally end up that wayThat's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
1.2 KW.
Yes, my infrequent attempts at humour generally end up that wayThat's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
1.2 KW.
I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
Ensuring that the device is encased and no heat is getting out sounds very sensible, yes. :)Plan is to replicate the Flight Thruster using 100Ws of RF during the static tests. At 150W, Shawyer got around 40mN or 4gf of thrust, which would give me around 25mN or 2.5gf. As my setup will be much lighter than Shawyers rotary system and will be using magnetic bearings, 2.5gf should be more than enough thrust to run load versus power consumed tests and generate a descent curve to show COE is obeyed or not.
My tests will be streamed, in real time, via YouTube & recorded. Will setup a web site with the stream links, run by run measurement results, plans, BOM, sources etc.Yes, my infrequent attempts at humour generally end up that wayThat's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
1.2 KW.
As long as we hear the results that's all that matters.
Although i have a slight inclination towards believe there is indeed an effect, simply because of shawyer's video of his dynamic test, because of the test performed in china and because the Eagleworks results, I still feel very uncomfortable about the silence Shawyer has on his first generation super cooled device.NDA, money, under contract, testing issues?
If I would have irrefutable and impressive results with a supercooled EMdrive, I would not hesitate to make it known to the world. I'm sure a lot of scientific and financial interest would come my way... but I'm not Shawyer... :)
still.. the question remains.. why the silence?
I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.As a one time ham, I'm not keen to crank up 1kW or more of power as there will be other issues to deal with at those power levels. Even at my max target of 100W, I suspect there may be issues to deal with.
For the other question, the thrust, as a physicist I keep on being rather sceptical because I tried to move my car by hitting the windscreen with punches and nothing happened.
It's good that at least one person understands what I'm on about. :-\
Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?
I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
Or you could also give the example of EM Drive ship 1 (which started from a different place) being overtaken by EM Drive ship 2 ...
EDIT:
See White and Joosten, Appendix :
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf
I just read this... Oh my!
deltaMass, I owe you an apology. I thought this was your derivation. I did not realize they published it that way. It was an assumption right from the start that acceleration is constant for constant input power. A "what if?" scenario. Fine, that's how the game is played if you want to get funded.
Thank you.
Todd
Plan is to replicate the Flight Thruster using 100Ws of RF during the static tests. At 150W, Shawyer got around 40mN or 4gf of thrust, which would give me around 25mN or 2.5gf. As my setup will be much lighter than Shawyers rotary system and will be using magnetic bearings, 2.5gf should be more than enough thrust to run load versus power consumed tests and generate a descent curve to show COE is obeyed or not.I imagine the chief source of friction will be the generator bearings. Or can these also be magnetic?
StrongGR may be talking about a closed-form solution for that case (without the dielectric insert), therefore a mathematical formula. Not necessarily including plots, as they are necessary for numerical solutions.I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
May I respectfully ask that you also include a visualization of the solution if possible? I'd very much like to see this.
Given the closed-form solution (for which we would be most thankful :) ) then all of us could make plots using our own software, for any numerical values we are interested in.
That's why closed-form solutions rock :)
Quote from: WarpTechHypothetically, if there were a black box with a gravitational field "inside", i.e., it has a NET acceleration vector along the X axis, pointing toward the blue side of the box..., (which is opposite the red side of the box) but has no discernible gravitational field "outside" of the box other than what a normal box of that mass would have. Let's say that inside the box there is all the equipment and energy storage, necessary to generate this field. Nothing comes in or goes out, but the energy stored inside it (battery) is being dissipated without being expelled.I must confess that I don't understand this system. It seems to suggest that a gravitational field can be generated at will de novo and also shielded. I wouldn't know where to start with something like that.
What sort of motion would YOU expect to see?
1. Will it move forward with the blue side leading?
2. Will it move forward with the red side leading?
3. Will it not move at all because nothing is coming out?
Keep in mind, by definition, it has a NET acceleration vector inside along the X axis.
Todd
Given the explosive number of posts in this thread, since the NSF article, how about if we divide the thread as follows
1) One thread for people that believe "EM Drive, Follow the Data, Ignore the Theory" (some posters have adhered to this principle of investigation, as of late)
and
2) another thread for those that rather continue with "EM Drive, Analyze data and Analyze theory" which was the original focus of threads EMDrive 1 and 2.
It will result in easier searching and less clutter.
The forum moderator may have to close this thread and start another one pretty soon, as this 2nd EM Drive thread is already approaching 140 pages, as threads cannot have an unlimited number of pages.
This is an excellent time to make this decision.
It will also be more in the spirit of this forum which is to keep threads focused on topic, as approach #1 above (which disregards any theory) is in conflict with approach #2 :)
Yes, my infrequent attempts at humour generally end up that wayThat's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
1.2 KW.
It's bad form to explain a joke, but I was implying that I hoped it wasn't -1 kW!Yes, my infrequent attempts at humour generally end up that wayThat's why they're building a high power test of ±1Kw or so, hopefully by July...I'm fairly sure it's +1 KW :P
1.2 KW.
As long as it's not "1.21 Jiggawatts!"
Given the explosive number of posts in this thread, since the NSF article, how about if we divide the thread as follows
1) One thread for people that believe "EM Drive, Follow the Data, Ignore the Theory" (some posters have adhered to this principle of investigation, as of late)
and
2) another thread for those that rather continue with "EM Drive, Analyze experiments and Analyze theory" which was the original focus of threads EMDrive 1 and 2.
It will result in easier searching and less clutter.
The forum moderator may have to close this thread and start another one pretty soon, as this 2nd EM Drive thread is already approaching 140 pages, as threads cannot have an unlimited number of pages.
This is an excellent time to make this decision.
It will also be more in the spirit of this forum which is to keep threads focused on topic, as approach #1 above (which disregards any theory) is in conflict with approach #2 :)
Dr. Rodal:
As promised, find attached a few related papers from work. As to the rest of your and Mulletron's concerns over the Eagleworks evolving theoretical musings on the EM-Drive propulsion topic, I leave you with Boyd Bushman's, (was senior scientist at LM/FW, now retired and passed-on), admonition to me when I first met him back in 2000 when discussing Jim Woodward's Mach-Effect work with Boyd's boss, "Follow the data, theory be dammed!" We intend to do just that, no matter where it might take us.
Best, Paul M.
I'm new here and I just thought I would post this video for you all. Its a very VERY sloppy experimental setup of something like the what people on this forum are talking about. The interesting thing here is the man in the video doesn't use end-plates and its quite a bit slimmer than the EM Drive. Here is the video:
youtube.com/watch?v=vcaOKX7Ko7w
What are some thoughts about the video posted?
Created Shawyer (EM Drive) engine is very easy and simple in its design . It provides the necessary thrust " by the oscillation of the microwaves inside the vacuum container ."
http: //hi-news.ru/technology/v-nasa-i ...
I decided that the system should not be closed
Feeling incapable of contributing much to the theoretical analysis I feel competent in building a device and providing accurate data. I have learned to think carefully before experiment/measurement so that I understand what is being measured, what the data is expected to reveal and why it is relevant. My point is both disciplined theoretical analysis and experimental data are useful.Glad to get another builder on board.
I'm talking about signs of atomization on the *outside* surface of the frustum. Although it would probably be happening in the inside as well. The copper atoms would be the propellent. I'm not sure what the mechanism would be, but it's obviously more than a thermal effect, and the whole reversal in phase/thrust would be difficult to explain. It seems more simple than QV or relativity models, but it's still probably interesting physics.Following on what jknuble said about the multipactor-like effect as a possible cause of thrust. http://en.wikipedia.org/wiki/Multipactor_effect I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust.
For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.
I can think of 3 ways to debunk this. 1) perhaps that amount of particles going that fast would be noticeable with the naked eye, so this isn't really a valid explanation. 2) stick a detector behind the thruster (are they ionized?). 3) SEM of the surface compared to scraps from the same batch of copper not used in the thrustum.
Just how would we get a net-thrust from a closed cavity with atomization. Even if atoms are being ioniozed inside the cavity I don't see how that could result in a net thrust. Atomization results in immediate thrust but then that creates impact on the other side of the cavity canceling out the propulsion.
It might also explain the interferometer results.
I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
Now, that's something we can all agree with :)
StrongGR may be talking about a closed-form solution for that case (without the dielectric insert), therefore a mathematical formula. Not necessarily including plots, as they are necessary for numerical solutions.I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
May I respectfully ask that you also include a visualization of the solution if possible? I'd very much like to see this.
Given the closed-form solution (for which we would be most thankful :) ) then all of us could make plots using our own software, for any numerical values we are interested in.
That's why closed-form solutions rock :)
Correct, I am providing some closed form equations for a simplified case that should describe correctly what observed recently at Eagleworks. As said before, I cannot find an explanation for thrust in the framework of general relativity. In the aforementioned Minotti's paper it is shown that one needs to modify the theory to account for it. Minotti's paper can be helpful to discuss the full problem and this will be work for the (very) near future. The point that I would like to understand is if the linearized Einstein theory could be enough. Probably so but my analysis for the simplified problem makes me think that a cavity can yield more for a laser propagating inside.
Eagleworks' results about the laser and the cavity are exciting because could pave the way both to table-top experiments in general relativity and space-time engineering as the technology to manage electromagnetic fields is well acquired.
Feel free to comment on this first draft.
One sees that there is an additional component to thelaserfield exiting the cavity that interacts with the mode inside. This can have terms with the frequency shifted and is a purely gravitational effect.
I have shown how a plane wave could produce a gravitational effect inside a cavity that could be observed using a propagating laser beam inside it. The effect could be unveiled using an interferometer or observing the components of thelaserfield outside the cavity. Components with a shifted frequency, due to the modes inside the cavity, should be seen. This could explain recent results at Eagleworks with a resonator having the form of a truncated cone. A local warp of the geometry due to the electromagnetic field pumped inside the cavity could be a satisfactory explanation
I hope this post wasn't too rambling or too full of misconceptions regarding the tests you have performed. I don't envy you folks trying to make progress on this complex issue via a public internet forum. Good luck, and again, I hope I'm wrong!Appreciate your post. Food for thought.
-Joseph Knuble,
NASA GSFC Code 555
Microwave Instrument Technology Branch
Final note for any students here who are curious about RF: This is far below the power levels I believe you have operated at but for future consideration at the 100W to KW level note the acoustic (i.e. pressure) effects of this demonstration which uses a 2.4GHz magnetron in a closed cavity with a contaminant: https://www.youtube.com/watch?v=RwTjsRt0Fzo Depending on the dynamics involved, teams which have tested at high power could be seeing the effects of a similar unstable vibration (think of your vibrating cell-phone skittering across the table.)
The point I'm making is this. You see these men sitting at the table together in this video? They're all on the same team....trying to figure out how to pull off interstellar flight. For the good of all of us. Now they're duking it out in an interview in Wired. They (like us) should all be working together, pooling resources, combined knowledge and experience. Instead a rift has formed, which will likely kill progress.
I do not want that to happen to this thread, which mas made pretty darn good progress so far. Not bad for a once unknown internet forum. Now back to work.
https://www.youtube.com/watch?v=ucyBMB_PWr8
Generator frictional losses will be significant. Scrap that idea.Quote from: TheTravellerPlan is to replicate the Flight Thruster using 100Ws of RF during the static tests. At 150W, Shawyer got around 40mN or 4gf of thrust, which would give me around 25mN or 2.5gf. As my setup will be much lighter than Shawyers rotary system and will be using magnetic bearings, 2.5gf should be more than enough thrust to run load versus power consumed tests and generate a descent curve to show COE is obeyed or not.I imagine the chief source of friction will be the generator bearings. Or can these also be magnetic?
It is entirely possible, and plausible, that Shawyer had to sell some of his knowledge to keep going and that now he has to keep his mouth shut about any progress made under the new owner.Although i have a slight inclination towards believe there is indeed an effect, simply because of shawyer's video of his dynamic test, because of the test performed in china and because the Eagleworks results, I still feel very uncomfortable about the silence Shawyer has on his first generation super cooled device.NDA, money, under contract, testing issues?
If I would have irrefutable and impressive results with a supercooled EMdrive, I would not hesitate to make it known to the world. I'm sure a lot of scientific and financial interest would come my way... but I'm not Shawyer... :)
still.. the question remains.. why the silence?
Shawyer did email Mullerton
...
Correct, I am providing some closed form equations for a simplified case that should describe correctly what observed recently at Eagleworks. As said before, I cannot find an explanation for thrust in the framework of general relativity. In the aforementioned Minotti's paper it is shown that one needs to modify the theory to account for it. Minotti's paper can be helpful to discuss the full problem and this will be work for the (very) near future. The point that I would like to understand is if the linearized Einstein theory could be enough. Probably so but my analysis for the simplified problem makes me think that a cavity can yield more for a laser propagating inside.
Eagleworks' results about the laser and the cavity are exciting because could pave the way both to table-top experiments in general relativity and space-time engineering as the technology to manage electromagnetic fields is well acquired.
Feel free to comment on this first draft.
Eagleworks' results about the laser and the cavity are exciting
... and because the cavity did not contain any polymer dielectric insert.
All-
The EM Drive wiki project (http://emdrive.echothis.com/) is starting to take shape - thanks in particular to @MazonDel who has begun adding and organizing content, including links back to the relevant posts and attachments on this forum and elsewhere. It's still very early, so any assistance is greatly appreciated! The site is run on MediaWiki (the same software used by Wikipedia) so it's quite easy to jump in and start contributing.
For those building their own test articles, I invite you to update this page (http://emdrive.echothis.com/Building) with your plans and links to any relevant photos, diagrams, videos, etc. We also have sections to list out the various theory proposals (http://emdrive.echothis.com/Theory), possible error sources (http://emdrive.echothis.com/Possible_Error_Sources) and a placeholder FAQ (http://emdrive.echothis.com/Frequently_Asked_Questions).
@Chris Bergin, feel free to link to this from the forums, when and if you think it would be of value to your visitors (particularly the newer ones).
-Rolf
StrongGR may be talking about a closed-form solution for that case (without the dielectric insert), therefore a mathematical formula. Not necessarily including plots, as they are necessary for numerical solutions.I will post here the solution for a very simple set-up of a cube cavity maintaining a single mode and show the way the laser beam propagates inside it. This resonant cavity seems to be very good for engineering of space-time rather than else.
May I respectfully ask that you also include a visualization of the solution if possible? I'd very much like to see this.
Given the closed-form solution (for which we would be most thankful :) ) then all of us could make plots using our own software, for any numerical values we are interested in.
That's why closed-form solutions rock :)
Correct, I am providing some closed form equations for a simplified case that should describe correctly what observed recently at Eagleworks. As said before, I cannot find an explanation for thrust in the framework of general relativity. In the aforementioned Minotti's paper it is shown that one needs to modify the theory to account for it. Minotti's paper can be helpful to discuss the full problem and this will be work for the (very) near future. The point that I would like to understand is if the linearized Einstein theory could be enough. Probably so but my analysis for the simplified problem makes me think that a cavity can yield more for a laser propagating inside.
Eagleworks' results about the laser and the cavity are exciting because could pave the way both to table-top experiments in general relativity and space-time engineering as the technology to manage electromagnetic fields is well acquired.
Feel free to comment on this first draft.
What an original contribution !
this is very interesting:Quote from: Marco FrascaOne sees that there is an additional component to thelaserfield exiting the cavity that interacts with the mode inside. This can have terms with the frequency shifted and is a purely gravitational effect.
This result is extremely interesting.Quote from: Marco FrascaI have shown how a plane wave could produce a gravitational effect inside a cavity that could be observed using a propagating laser beam inside it. The effect could be unveiled using an interferometer or observing the components of thelaserfield outside the cavity. Components with a shifted frequency, due to the modes inside the cavity, should be seen. This could explain recent results at Eagleworks with a resonator having the form of a truncated cone. A local warp of the geometry due to the electromagnetic field pumped inside the cavity could be a satisfactory explanation
This justifies Dr. White's attempts to measure these effects with an interferometer
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37438.0;attach=827718;image)
I'm looking forward to your attempt at dealing with a truncated cone geometry (difficult geometry to analyze)
I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
I personally use LiFePO4 batteries, as they are inherently safer than alternatives. For instance, I have one (about 1kg) with 8400mAh capacity and 30C continuous discharge capability (252 amps). You can extract ~1kW for a couple minutes, which should be enough for measurements. Recharging is also fast.
Now, that's something we can all agree with :)
I second that statement! You know I have some old wire mesh (old front door screen) to build a cone shaped can, connect some wires to an old and discarded microwave, power it and Bingo, Warp Drive! It's not that simple and what if I, by the shot in the dark make something that does work better than anything out there? I've accomplished very little as the other part of the equation of why, isn't there. Theory, Design, Engineering and Testing all go hand in hand. One aspect may leapfrog another during a process.
I have no solid clue why this EM drive works, sure there are some great theories (some of them have "warped" my little brain) out there. I have no doubt a answer will make itself known by Developing Theories, Designing, Building, Testing in synergy.
My engineer's gut tells me the best device for "Replicators" would be the Flight Thruster as it uses narrow band RF, which can be generated by a programmable RF generator, with an auxiliary RF amplifier and the RF energy feed into the cavity by standard RF connectors and coax. This gives good control over both frequency and power, which is not really available with a magnetron based RF generator, plus stops the need to add waveguides into the build.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
I personally use LiFePO4 batteries, as they are inherently safer than alternatives. For instance, I have one (about 1kg) with 8400mAh capacity and 30C continuous discharge capability (252 amps). You can extract ~1kW for a couple minutes, which should be enough for measurements. Recharging is also fast.
LiFePO4 is a good battery tech..better, safer than others out there though not quite as much power/mass. For short tests, I think that whatever can be effectively used is good. For actual vehicles, where safety and reliability is required, I'd want LiFePO4.
Regarding your earlier comments, about just using more power to get results: I think we're going to see two different methodologies here, the first being what Eagleworks is doing, which is carefully thought out, precision science, with work on theory to explain and therefore maximize efficiency. The other approach is the hacker approach, which is more of a mechanical and pragmatic approach, of doing things like applying more power or using different materials based upon hunches...that the proof will be in the pudding, so to speak. The problems arise when trying to unify the approaches - without some really fantastic results (such as a flying car), no one is going to let a hacker near the precision and certified labs to prove their claims, and the naysayers will have a field-day with "outlandish claims". Much of the guff EMdrive etc have received so far is because of insufficient theory and tests. I don't have a PhD in physics, and even if I did, if I wasn't prominent in the field I'd see no reason why Eagleworks or other reputable places would waste their time with me or the hundred other 'crackpots' in serious tests.
The exception to this may be if a program were implemented for inexpensive, quick, formal tests. An example which passed these tests would then be eligible for further testing and scrutiny. I think that such a program would be the best interface between the 'hackers' and the 'scientists'.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
That just jogged my memory. Check out www.zooniverse.orgI think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
I personally use LiFePO4 batteries, as they are inherently safer than alternatives. For instance, I have one (about 1kg) with 8400mAh capacity and 30C continuous discharge capability (252 amps). You can extract ~1kW for a couple minutes, which should be enough for measurements. Recharging is also fast.
LiFePO4 is a good battery tech..better, safer than others out there though not quite as much power/mass. For short tests, I think that whatever can be effectively used is good. For actual vehicles, where safety and reliability is required, I'd want LiFePO4.
Regarding your earlier comments, about just using more power to get results: I think we're going to see two different methodologies here, the first being what Eagleworks is doing, which is carefully thought out, precision science, with work on theory to explain and therefore maximize efficiency. The other approach is the hacker approach, which is more of a mechanical and pragmatic approach, of doing things like applying more power or using different materials based upon hunches...that the proof will be in the pudding, so to speak. The problems arise when trying to unify the approaches - without some really fantastic results (such as a flying car), no one is going to let a hacker near the precision and certified labs to prove their claims, and the naysayers will have a field-day with "outlandish claims". Much of the guff EMdrive etc have received so far is because of insufficient theory and tests. I don't have a PhD in physics, and even if I did, if I wasn't prominent in the field I'd see no reason why Eagleworks or other reputable places would waste their time with me or the hundred other 'crackpots' in serious tests.
The exception to this may be if a program were implemented for inexpensive, quick, formal tests. An example which passed these tests would then be eligible for further testing and scrutiny. I think that such a program would be the best interface between the 'hackers' and the 'scientists'.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.
From what I distill from some of the information I have read, coronal discharges were already plaguing some of the teams at power between 100 and 1000 Watts. a 300KW burst would probably fry everything we can throw at it and would require serious re-design of the components and use of materials, if at all possible.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.
How about using Tesla batteries for a few seconds (>300 KW?) and send the damn thing at the other side of the galaxy? Would that form a convincing test result?
I must reject the analysis by J & W in Appendix A, but thanks for the link.
I have already mentioned in my preamble that not only is any propellantless propulsion craft capable of perpetuum mobile operation, but that free energy is available on top of that to boot.
This causes many people to break out in hives, or to resort to chewing their towels. ::)
We can of course test to see this at work. We use a rotary configuration and when the tangential velocity exceeds 2/k, we switch from external power to a coaxially mounted generator. And then begin charging people for the juice. Outrageous! 8)
I may be asking a stupid question, but has anyone ever tried Pulse Width Modulation with the micro waves? To see how that effects forces within the cavity? Or has that mathematically been ruled out? Or?My engineer's gut tells me the best device for "Replicators" would be the Flight Thruster as it uses narrow band RF, which can be generated by a programmable RF generator, with an auxiliary RF amplifier and the RF energy feed into the cavity by standard RF connectors and coax. This gives good control over both frequency and power, which is not really available with a magnetron based RF generator, plus stops the need to add waveguides into the build.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
I personally use LiFePO4 batteries, as they are inherently safer than alternatives. For instance, I have one (about 1kg) with 8400mAh capacity and 30C continuous discharge capability (252 amps). You can extract ~1kW for a couple minutes, which should be enough for measurements. Recharging is also fast.
LiFePO4 is a good battery tech..better, safer than others out there though not quite as much power/mass. For short tests, I think that whatever can be effectively used is good. For actual vehicles, where safety and reliability is required, I'd want LiFePO4.
Regarding your earlier comments, about just using more power to get results: I think we're going to see two different methodologies here, the first being what Eagleworks is doing, which is carefully thought out, precision science, with work on theory to explain and therefore maximize efficiency. The other approach is the hacker approach, which is more of a mechanical and pragmatic approach, of doing things like applying more power or using different materials based upon hunches...that the proof will be in the pudding, so to speak. The problems arise when trying to unify the approaches - without some really fantastic results (such as a flying car), no one is going to let a hacker near the precision and certified labs to prove their claims, and the naysayers will have a field-day with "outlandish claims". Much of the guff EMdrive etc have received so far is because of insufficient theory and tests. I don't have a PhD in physics, and even if I did, if I wasn't prominent in the field I'd see no reason why Eagleworks or other reputable places would waste their time with me or the hundred other 'crackpots' in serious tests.
The exception to this may be if a program were implemented for inexpensive, quick, formal tests. An example which passed these tests would then be eligible for further testing and scrutiny. I think that such a program would be the best interface between the 'hackers' and the 'scientists'.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
I'm doing as close as possible to Shawyer replication as I can as I feel the closer I stay to Shawyer, the higher the chance of success. WHEN that works I may start trying stuff outside what Shawyer has shared.
From what I distill from some of the information I have read, coronal discharges were already plaguing some of the teams at power between 100 and 1000 Watts. a 300KW burst would probably fry everything we can throw at it and would require serious re-design of the components and use of materials, if at all possible.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.
How about using Tesla batteries for a few seconds (>300 KW?) and send the damn thing at the other side of the galaxy? Would that form a convincing test result?
...
My engineer's gut tells me the best device for "Replicators" would be the Flight Thruster as it uses narrow band RF, which can be generated by a programmable RF generator, with an auxiliary RF amplifier and the RF energy feed into the cavity by standard RF connectors and coax. This gives good control over both frequency and power, which is not really available with a magnetron based RF generator, plus stops the need to add waveguides into the build.
...
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
Saw the conic data. Nicely done....
My engineer's gut tells me the best device for "Replicators" would be the Flight Thruster as it uses narrow band RF, which can be generated by a programmable RF generator, with an auxiliary RF amplifier and the RF energy feed into the cavity by standard RF connectors and coax. This gives good control over both frequency and power, which is not really available with a magnetron based RF generator, plus stops the need to add waveguides into the build.
...
Another advantage to replicate the Flight Thruster, is that the Flight Thruster is one of only two designs that are close to what appears to be the optimum cone angle (7.5 degrees). Only the Shawyer Experimental and Shawyer's Flight Thruster are close to this optimum geometry:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1370559#msg1370559
I am not an engineer, a scientist, or an inventor. I am just an english major who writes science fiction and thinks this is really cool. So, that said, is there any chance that the guys at Eagleworks are ever going to have a Gofundme? Is there any way for all the people watching this project who don't have technical skills to kick in a little money to fund those who DO?
Just asking. Seems crowdfunding might help get around some of the "big organizations won't fund our research" problem.
The point I'm making is this. You see these men sitting at the table together in this video? They're all on the same team....trying to figure out how to pull off interstellar flight. For the good of all of us. Now they're duking it out in an interview in Wired. They (like us) should all be working together, pooling resources, combined knowledge and experience. Instead a rift has formed, which will likely kill progress.
....Yes I have calculated it, but it is a Mathematica program, not an Excel spreadsheet. I posted (earlier in the thread) comparisons of the measurements vs. predictions using Shawyer's and McCulloch's formulas.
Did you or anyone else ever write an excel spreadsheet to calc Shawyers Design Factor? If so pls link it or if not please consider doing it as your skills there are much better than mine.
That's why everybody would be well-advised never to talk to reporters, unless they can be assured in writing by the reporter that nothing will get published without their prior approval ;)The point I'm making is this. You see these men sitting at the table together in this video? They're all on the same team....trying to figure out how to pull off interstellar flight. For the good of all of us. Now they're duking it out in an interview in Wired. They (like us) should all be working together, pooling resources, combined knowledge and experience. Instead a rift has formed, which will likely kill progress.
it seems to me Wired totally distorted what Davis and Millis said. Most comments also note that.
Yup.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
Radar magnetrons operate in pulsed mode. The output power during the pulse may be 20 kW but the duration is very short and so the average power output is very low. Any high power CW magnetron is very dangerous to play with when it is removed from the equipment it was designed for. The RF discharges can cause serious injury and temporary blindness.
The problems with coronal discharges were with amplifiers. Magnetrons aren't affected by this, as they have no capacitors.From what I distill from some of the information I have read, coronal discharges were already plaguing some of the teams at power between 100 and 1000 Watts. a 300KW burst would probably fry everything we can throw at it and would require serious re-design of the components and use of materials, if at all possible.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.
How about using Tesla batteries for a few seconds (>300 KW?) and send the damn thing at the other side of the galaxy? Would that form a convincing test result?
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
Radar magnetrons operate in pulsed mode. The output power during the pulse may be 20 kW but the duration is very short and so the average power output is very low. Any high power CW magnetron is very dangerous to play with when it is removed from the equipment it was designed for. The RF discharges can cause serious injury and temporary blindness.
The nice thing about magnetrons is you get a lot of power without having to use an amplifier, and hence capacitors, which don't behave well in vacuum. Of course, if you're not worried about tests in a vacuum, then something less of an RF sledgehammer, some RF signal generator with more finesse, has advantages. But, amplification becomes expensive. TWTs (Travelling Wave Tubes) are more expensive that Magnetrons. I intend to used both approaches, but will probably start with the Magnetron, in an attempt to replicate Shawyer's work, before I do anything else.My engineer's gut tells me the best device for "Replicators" would be the Flight Thruster as it uses narrow band RF, which can be generated by a programmable RF generator, with an auxiliary RF amplifier and the RF energy feed into the cavity by standard RF connectors and coax. This gives good control over both frequency and power, which is not really available with a magnetron based RF generator, plus stops the need to add waveguides into the build.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.Which battery types would you recommend for 1 KW operation?
I personally use LiFePO4 batteries, as they are inherently safer than alternatives. For instance, I have one (about 1kg) with 8400mAh capacity and 30C continuous discharge capability (252 amps). You can extract ~1kW for a couple minutes, which should be enough for measurements. Recharging is also fast.
LiFePO4 is a good battery tech..better, safer than others out there though not quite as much power/mass. For short tests, I think that whatever can be effectively used is good. For actual vehicles, where safety and reliability is required, I'd want LiFePO4.
Regarding your earlier comments, about just using more power to get results: I think we're going to see two different methodologies here, the first being what Eagleworks is doing, which is carefully thought out, precision science, with work on theory to explain and therefore maximize efficiency. The other approach is the hacker approach, which is more of a mechanical and pragmatic approach, of doing things like applying more power or using different materials based upon hunches...that the proof will be in the pudding, so to speak. The problems arise when trying to unify the approaches - without some really fantastic results (such as a flying car), no one is going to let a hacker near the precision and certified labs to prove their claims, and the naysayers will have a field-day with "outlandish claims". Much of the guff EMdrive etc have received so far is because of insufficient theory and tests. I don't have a PhD in physics, and even if I did, if I wasn't prominent in the field I'd see no reason why Eagleworks or other reputable places would waste their time with me or the hundred other 'crackpots' in serious tests.
The exception to this may be if a program were implemented for inexpensive, quick, formal tests. An example which passed these tests would then be eligible for further testing and scrutiny. I think that such a program would be the best interface between the 'hackers' and the 'scientists'.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
I'm doing as close as possible to Shawyer replication as I can as I feel the closer I stay to Shawyer, the higher the chance of success. WHEN that works I may start trying stuff outside what Shawyer has shared.
Mathematica looks interesting but maybe later as I suspect there would be a learning curve.....Yes I have calculated it, but it is a Mathematica program, not an Excel spreadsheet. I posted (earlier in the thread) comparisons of the measurements vs. predictions using Shawyer's and McCulloch's formulas.
Did you or anyone else ever write an excel spreadsheet to calc Shawyers Design Factor? If so pls link it or if not please consider doing it as your skills there are much better than mine.
You may want to PM @aero to ask whether he did it with Excel (if my memory is correct @aero also calculated Shawyer's Design Factor, as I recall having exchanges in this forum with him).
And of course, when running your program, you will first check your results vs. Shawyer's published Design Factor results, etc., to make sure that your program is correct.
The problems with coronal discharges were with amplifiers. Magnetrons aren't affected by this, as they have no capacitors.
Tesla's batteries are unobtanium for the next year, it appears, so I am not even evaluating them at this stage.
@TheTravellerThanks for that info.
I know the guy with the magnetic bearing in that vid you posted - a bloke called Craigy, now works out of a private R&D lab in east London. We were both members of Steorn's SKDB (aka "The Spudclub") and what you see in the video is a rough draught of one of Steorn's low-friction bearings, a design that came to be known as "nero zero" for its low friction (not to be confused with their patented Earnshaw-defying "Zero-F" bearings which are entirely non-contact passive bearings).
The basic design for a nero zero bearing is pretty much what you see there, although can be improved by using a diametrically-polarised NdFeB disc magnet on the bottom of the vertical shaft, levitating above a toroidal NdFeB - ideally of N42 grade or better if possible. The top of the shaft tapers to a needle, resting in a jewel cup. The jewel is affixed to the underside of a micrometer head, so that the ride height of the whole shaft + disc magnet assembly can be adjusted over the ring magnet stator; this allows accurate tuning of stability vs friction. I actually still have one here lying around... we used to test them in terms of their wind-down period, and a well set up rig weighing a just a couple of hundred grams can easily achieve wind-downs of 10 minutes from 1,000 rpm.
The fully Zero-F bearings (no contact) are slightly more complex, using a mixture of paramegnetic and ferromagnetic materials - hence why they're not truly Earnshaw-exceptions, although they achieve the same end - but the nero-zero articles are good enough for measuring in the nJ range.. We used to use laser tachos, establish the MoI and baseline loss rates then calculate magnetic interaction efficiencies from there... You can find everything cheap on eBay, and even get magnets made to your own specs for very little..
Which is why using a programmable RF generator that also allows output level to be varied, allows use of low power to lock the RF frequency to the cavity and then slowly increase power as you continue to seek cavity lock.
The problems with coronal discharges were with amplifiers. Magnetrons aren't affected by this, as they have no capacitors.
Tesla's batteries are unobtanium for the next year, it appears, so I am not even evaluating them at this stage.
RF arcing occurs with any kind of RF amplifier if the load is not matched. It has nothing to do with capacitors. When the amplifier experiences a high SWR power is reflected back to the amplifier. This creates a standing wave on the feedline. The high voltages present on the feedline can destroy a solid state amplifier. Tube amplifers are more resistant to this kind of damage and often provide a visual indication; but internal arcing can destroy them as well. The main problem is that the cavity's high Q (several 100k or k depending on how it is measured ;)) means it is next to impossible to tune the drive to resonance. So most of the power is reflected.
Mathematica looks interesting but maybe later as I suspect there would be a learning curve.....Yes I have calculated it, but it is a Mathematica program, not an Excel spreadsheet. I posted (earlier in the thread) comparisons of the measurements vs. predictions using Shawyer's and McCulloch's formulas.
Did you or anyone else ever write an excel spreadsheet to calc Shawyers Design Factor? If so pls link it or if not please consider doing it as your skills there are much better than mine.
You may want to PM @aero to ask whether he did it with Excel (if my memory is correct @aero also calculated Shawyer's Design Factor, as I recall having exchanges in this forum with him).
And of course, when running your program, you will first check your results vs. Shawyer's published Design Factor results, etc., to make sure that your program is correct.
Is this still your Design Factor equation?
Thanks for your assistance. Most appreciated.
Latest paper by Dr. White, on http://ntrs.nasa.gov/ , exploring the idea of the quantum vacuum not being an absolute immutable and nondegradable state, and examining some rami cations of the quantum vacuum being able to support non-trivial spatial variations in density. They claim that their "considerations showed no predictions that were contrary to observation, and in fact duplicated predictions for energy states associated with the primary quantum number."
http://hdl.handle.net/2060/20150006842
Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom
Harold White, Jerry Vera,y Paul Bailey,z Paul March,x Tim Lawrence,{ Andre Sylvester, and David Brady
NASA Johnson Space Center
2101 NASA Parkway, Houston, TX 77058
(Dated: April 2, 2015)
Publication Date: Apr 02, 2015
Document ID:
20150006842 (Acquired Apr 28, 2015)
Subject Category: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ATOMIC AND MOLECULAR PHYSICS; NUMERICAL ANALYSIS; COMPUTER PROGRAMMING AND SOFTWARE
Report/Patent Number: JSC-CN-33080
Document Type: Technical Report
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 9p; In English
Which is why using a programmable RF generator that also allows output level to be varied, allows use of low power to lock the RF frequency to the cavity and then slowly increase power as you continue to seek cavity lock.
In Shawyers 1st 2 units, the Feasibility and the Demonstrator devices, the cavity was physically tuned to the RF signal, a magnetron. You can listen to Shawyer saying the initial part of the rotary Demonstrator test produced no thrust until the magnetron LOCKED to the cavity. I suspect what really happened was the stepper motor at the small end of the cavity, mechanically tuned the cavity to the magnetron frequency and then thrust happened.
Look at the gears and stepper motors fitted to the small end of the Demonstrator EM Drive. Very clever mechanics but not needed if you use a narrow band programmable RF source and use spherical end plates.
Shawyer learned much from his 1st 2 EM Drives and applied it all to the Flight Thruster. No physical cavity tuning needed as he used a programmable RF generator which feeds a RF amplifier. Plus he uses a sensor in the big end to provide feedback for his frequency control loop to ensure the cavity Rf frequency is always at the right frequency to dump the max RF energy into the cavity to generate the max thrust.
as an engineer, I look at the development history and my guts says, good job Mr Shawyer.
Added emphasis. If it can be of any comfort to you, I understand both your arguments and humour (so far).Gratifying because I'm sure many don't. We do seem to think along the same lines. On a practical note, I think the next step is to predict how best to distinguish the "trash Noether" or "trash Einstein" models. This comes down to doing what TheTraveller describes when comparing input and output power using some sort of rotary device. We will have a differential equation that includes velocity-dependent friction. We will need to devise a good metric so as to be able to best differentiate between the two scenarios based on the Pout vs. Pin data. I am handwaving here because I have not yet drilled down on this.
Another way to get high power from a small battery pack is to use non-rechargeable liquid-electrolyte lithium batteries. They have a hell of a capacity per kilogram. Put a good few of those in series and parallel and you can probably power up to 2.5 kW for a short time. Disadvantage is that they are non-rechargeable and not exactly cheap.. But they could be useful for short duration high power tests to check linearity or whatever you science guys want for comparison with lower power tests.The problems with coronal discharges were with amplifiers. Magnetrons aren't affected by this, as they have no capacitors.From what I distill from some of the information I have read, coronal discharges were already plaguing some of the teams at power between 100 and 1000 Watts. a 300KW burst would probably fry everything we can throw at it and would require serious re-design of the components and use of materials, if at all possible.I think that the solution is really simple, if it's about demonstrating a thrust effect that is many times larger than measurement precision: Crank up the RF power. A lot. There is really no two ways about it. Please don't even try to play with a power level that even a 9V-battery can put out.. . Personally, I'd play in a power regime of about 1kW (actually I do, but that's another story..) . 1KW is a level that can easily be handled by readily available parts and off-the-shelf electronics, but is still not excessive.
How about using Tesla batteries for a few seconds (>300 KW?) and send the damn thing at the other side of the galaxy? Would that form a convincing test result?
Tesla's batteries are unobtanium for the next year, it appears, so I am not even evaluating them at this stage.
I know Shawyer and EW have tried a dielectric in the frustum. Are there any specifications for that dielectric? Material properties? Absorption properties at microwave frequencies?
I was looking at Pyramid Absorbers for microwaves, they can attenuate up to -55dB. A high power microwave source, pumped through a diode into such an absorber, seems to me should have a higher probability of thrust than the EM Drive and relatively simple to construct.
Todd D.
RF loss tangent from that of HDPE (~0.0004)
Okay, well I'm a first time poster, I'm not a physics major, or mathematician, and I'm expecting people to shoot down what I'm going to say anyways, but hopefully someone will pay it a little mind. That said, I think I may have an idea about this that may just answer many of the problems that most people have with the still-experimental results that Dr. White is posting here.As far as the QV goes, and also assuming all the thing you just assumed (also my preference) the QV could be considered point-like when you actually tap into it. A singularity. Only difference is this singularity is the same singularity where ever in the universes spacetime you poke a hole. No matter where you are, poke a hole in spacetime and you are tapping into the exact same singularity. Not a singularity like a black hole as we know it, but one that is the result of a higher dimensional Quantum Vacuum. In that higher dimension, the QV could be anything, We cant know that. Some accepted theories use more than our 3+1 spacetime dimensions. Having no dimensions to us means that it also has no preferred reference frame, solving that part of GR. What it manifests itself as could be in fact like the earth is for our electricity grid. It doesn't matter where on earth you are you can use it as a return for your power line.
I will start by saying that I really don't know what math exactly would be involved, and if anyone DOES know, and is willing to either do it, or help me do it, then feel free! Also I'm going to start my theory making only 3 assumptions. They are as follows.
Assumption 1) That the results Dr. White is posting are correct, and unbiased, that he has followed scientific protocols within the limits of his abilities, and that he has drawn conclusions from empirical evidence as is the scientific method.
Assumption 2) That the suspected warp-bubble like effects are NOT a malfunction of scientific instrumentation, and are not being either misrepresented, or misinterpreted.
Assumption 3) The laws of physics are in fact NOT being broken.
Now assumption 3 is of course the big one that everyone has a problem with, but if you hear me out I believe you may be able to come to an understanding about it.
You see the law of conservation of momentum, easily stated, is that every action has an equal and opposite reaction. Of course, being a law, it is inviolable, and anything that does not conform to it cannot exist, and has to be immediately discarded as junk science, right? And of course the EMDrive DOES seem to break this law, and therefore it has to be fake, or some kind of misunderstanding.
But what if it ISN'T breaking that law? What if instead we include ANOTHER law of physics.
The law of conservation of energy.
You see, energy cannot be created, or destroyed, it can only change forms. So if we are not seeing an equal and opposite reaction in kinetic energy, than perhaps the energy has been converted to some other form, and THIS is in fact the reason why the EMDrive actually works, as it is effectively converting kinetic energy from one direction into some other form of energy, and ergo there is a net thrust differential.
But what form would this energy take? Waste heat is always a good culprit, as entropy states. But that doesn't seem to be the whole store, so perhaps could there be a different answer?
Dr. White has theorized that the EMDrive is in some way interacting with the quantuum vacuum (and other scientists have theorized the same). IF it is in fact interacting with the quantuum vacuum in some manner, than perhaps this may give us the solution to the warp-field being detected.
The quantuum vacuum is often stated as being the lowest possible energy-state of the universe, or in another way of looking at it, a state of 0 energy, which is of course why you can't extract thrust from it, or interact with it, because there's no energy to be extracted.
However, if you DID in fact do so, you would in essence be creating a negative energy sum. which when added to the thrust of the EMDrive, would equate to a 0-sum, and thus an equal, and opposite, reaction. Just that the reaction would not be in a form that we would recognize as momentum, ergo, it appears to us as net thrust.
If that is the case, this would satisfy some of the requirements of Alcubierre's theorem, allowing for the production of warp-bubbles, which in turn would explain the interference pattern that has been detected.
Again, this is all just conjecture, and perhaps my understanding of physics is horribly flawed, or someone will do the math involved, and just disprove what I postulated. However, if it's accurate, it would in essence explain all of the results we have experienced, and effectively wrap everything up in a neat little package that actually makes sense, and does NOT defy the laws of physics.
Now as for HOW it is converting that energy, THAT I have no idea, but again, this is just something I came up with today. Feel free to poke holes in it.
Using low temps and low power is definitely the way to go during this "how does it work?" phase. Much safer. But keep your eyes away from it and have a microwave leak detector at hand.2.45GHz is home microwave oven frequency. Most run around 600W. I'm sure forum menber have seen what 600W of microwave can do in regard to plasma creation and other pryotechinque tricks in a microwave oven.
The high-power engineering can be done after the basic principles involved are understood.
@TheTravellerhttp://www.alibaba.com/product-detail/2014-promotional-bldc-motor-magnetic-bearing_1803241008.html
A small, slow-speed generator with magnetic bearings is I think what you need. I have looked but so far had no luck. One can find them in profusion, however, for direct drive power generation from a wind power machine. These are of course massive and expensive.
But..if those pulses have enough duration to make measurements..one could potentially see what happens at those powers without scaling the dangers with it so much.
I've been looking at surplus 20kw radar magnetrons on ebay, and the availability of 3D printed silicons carbide base on which to plate my Magnesium diboride superconductor, and also at cryocoolers. It's all very complex and expensive, and with the cryo, somewhat dangerous. I am most definitely in the realm of a 'hacker' in this endeavor (and have been so in other fields for a number of years), so I know what to expect (or at least I think I do).
Radar magnetrons operate in pulsed mode. The output power during the pulse may be 20 kW but the duration is very short and so the average power output is very low. Any high power CW magnetron is very dangerous to play with when it is removed from the equipment it was designed for. The RF discharges can cause serious injury and temporary blindness.
Thanks a lot! Indeed my idea was to justify White's results that appear already striking from a physicist's standpoint. I am working on the frustum case and I hope to update the paper soon.
Looks interesting.@TheTravellerhttp://www.alibaba.com/product-detail/2014-promotional-bldc-motor-magnetic-bearing_1803241008.html
A small, slow-speed generator with magnetic bearings is I think what you need. I have looked but so far had no luck. One can find them in profusion, however, for direct drive power generation from a wind power machine. These are of course massive and expensive.
might fit the bill, using good quality gearing so the gennie runs fast
Can someone explain why the EMdrive experiment isn't run inside Helmholtz Coils (to cancel Earth magnetic field)?It's all AC past the tie-off points, so there's no net current for this effect.
The propulsion could be easily explained by the interaction between the large DC currents used to operate the magnetron/RF power amplifier with Earth’s magnetic field by way of the Lorentz force. In other words, a homopolar motor. This is an experiment that any child can do with a battery and a piece of wire:
http://en.wikipedia.org/wiki/Homopolar_motor
To do a proper measurement, the Earth's magnetic field should be canceled around the experiment using this setup:
http://en.wikipedia.org/wiki/Helmholtz_coil
Can someone explain why the EMdrive experiment isn't run inside Helmholtz Coils (to cancel Earth magnetic field)?
The propulsion could be easily explained by the interaction between the large DC currents used to operate the magnetron/RF power amplifier with Earth’s magnetic field by way of the Lorentz force. In other words, a homopolar motor. This is an experiment that any child can do with a battery and a piece of wire:
http://en.wikipedia.org/wiki/Homopolar_motor
To do a proper measurement, the Earth's magnetic field should be canceled around the experiment using this setup:
http://en.wikipedia.org/wiki/Helmholtz_coil
Can someone explain why the EMdrive experiment isn't run inside Helmholtz Coils (to cancel Earth magnetic field)?
The propulsion could be easily explained by the interaction between the large DC currents used to operate the magnetron/RF power amplifier with Earth’s magnetic field by way of the Lorentz force. In other words, a homopolar motor. This is an experiment that any child can do with a battery and a piece of wire:
http://en.wikipedia.org/wiki/Homopolar_motor
To do a proper measurement, the Earth's magnetic field should be canceled around the experiment using this setup:
http://en.wikipedia.org/wiki/Helmholtz_coil
Assuming one believes Shawyer's experimental reports, wouldn't that interaction with the Earth's negative field be negated by the fact that Shawyer claims to have measured similar thrust/PowerInput for the EM Drive pointing small base UP (vertical), small base DOWN (vertical), small base to the RIGHT (horizontal) ?
There is still a shared ground connection between the source and the device-under-test, so it's not fully balanced AC. You can never be sure about residual ground currents, ground loops etc. It can easily cause this residual force, and explain the large variation between various experimental setups.
It would be a wise precaution to run this experiment inside Helmholtz coils to cancel possible interactions with Earth's magnetic field.
...
I referring to NASA's experimental setup, not Shawyer's. (I consider Shawyer's setup to be too sloppy - rotating platform, with laptop? with fans? and rotating hard-disk? Extremely unprofessional).
In NASA's setup, there is still a shared ground connection between the source and the device-under-test, so it's not fully balanced AC. You can never be sure about residual ground currents, ground loops etc. It can easily cause this residual force, and explain the large variation between various experimental setups.
It would be a wise precaution to run this experiment inside Helmholtz coils to cancel possible interactions with Earth's magnetic field.
The maximum thrust, measured using a precision balance was 16mN for an input power of 850W, which is very close to the thrust of 16.6mN predicted from equation 1.
The thrust could be varied from zero to maximum by varying the input power, or by varying the resonant frequency of the thruster. Considerable efforts were made to test for possible thermal and electromagnetic spurious effects. The primary method was to carry out all tests in both nominal and inverted orientations, and to take the mean of the results. The thruster was also sealed into a hermetic enclosure to eliminate buoyancy effects of the cooling air. Three different types of test rig were used, two using 1 mg resolution balances in a counterbalance test rig and one using a 100 mg resolution balance in a direct measurement of thruster weight.
Comparison of the rates of increase of thrust for the different spring constants, using pulsed input power, gave a clear proof that the thrust was produced by momentum transfer and was not due to any “undefined” spurious effect.
The total test programme encompassed 450 test runs of periods up to 50 seconds, using 5 different magnetrons.
Extremely unprofessional?
There is still a shared ground connection between the source and the device-under-test, so it's not fully balanced AC. You can never be sure about residual ground currents, ground loops etc. It can easily cause this residual force, and explain the large variation between various experimental setups.I ran the numbers and was surprised how little current it takes. I assumed it ran in the shield of the RF feed coax and took length to be 0.5m. That yields 4 Amps of ground loop current necessary to produce 100 uN in the Earth's field.
It would be a wise precaution to run this experiment inside Helmholtz coils to cancel possible interactions with Earth's magnetic field.
...
4) Considering the HDPE dielectric acting as a sink (energy flowing from the EM Drive towards the HDPE where the energy is dissipated internally in the dielectric polymer due to its tandelta and hence irretrievably lost instead of being reflected), the Poynting vector would be directed towards the HDPE dielectric, that is towards the small base, and hence the EM Drive should experience a recoil force and acceleration towards the big base. This is the opposite direction force found in NASA's experiments with the dielectric. (Recall that NASA Eagleworks found no thrust force with mode TE012 without a HDPE dielectric and that with the HDPE dielectric inserted at the small base they found a force and acceleration directed towards the small base.)
EW is actually replicating Shawyers Teeter Totter balance beam for their next round.Can someone explain why the EMdrive experiment isn't run inside Helmholtz Coils (to cancel Earth magnetic field)?
The propulsion could be easily explained by the interaction between the large DC currents used to operate the magnetron/RF power amplifier with Earth’s magnetic field by way of the Lorentz force. In other words, a homopolar motor. This is an experiment that any child can do with a battery and a piece of wire:
http://en.wikipedia.org/wiki/Homopolar_motor
To do a proper measurement, the Earth's magnetic field should be canceled around the experiment using this setup:
http://en.wikipedia.org/wiki/Helmholtz_coil
Assuming one believes Shawyer's experimental reports, wouldn't that interaction with the Earth's negative field be negated by the fact that Shawyer claims to have measured similar thrust/PowerInput for the EM Drive pointing small base UP (vertical), small base DOWN (vertical), small base to the RIGHT (horizontal) ?
I referring to NASA's experimental setup, not Shawyer's. (I consider Shawyer's setup to be too sloppy - rotating platform, with laptop? with fans? and rotating hard-disk? Extremely unprofessional).
In NASA's setup, there is still a shared ground connection between the source and the device-under-test, so it's not fully balanced AC. You can never be sure about residual ground currents, ground loops etc. It can easily cause this residual force, and explain the large variation between various experimental setups.
It would be a wise precaution to run this experiment inside Helmholtz coils to cancel possible interactions with Earth's magnetic field.
He's referring to spurious angular momentum from various rotating components of the test equipment possibly coupling into the angular momentum of the platform on the air bearing.Quote from: BubsExtremely unprofessional?
Using low temps and low power is definitely the way to go during this "how does it work?" phase. Much safer. But keep your eyes away from it and have a microwave leak detector at hand.2.45GHz is home microwave oven frequency. Most run around 600W. I'm sure forum menber have seen what 600W of microwave can do in regard to plasma creation and other pryotechinque tricks in a microwave oven.
The high-power engineering can be done after the basic principles involved are understood.
Using a 1kW magnetron could do serious damage to people & equipment around a EM Drive if any microwave energy escaped. So please use microwave leak detectors and limit time close to the cavity.
Shawyer has experienced this. He made this comment about leaking microwaves interfering with his video camera when filming the rotary test rig.
Is why I'll build a Faraday Cage around my test unit so to stop microwave leaks interfering with my test and control system.
There is still a shared ground connection between the source and the device-under-test, so it's not fully balanced AC. You can never be sure about residual ground currents, ground loops etc. It can easily cause this residual force, and explain the large variation between various experimental setups.I ran the numbers and was surprised how little current it takes. I assumed it ran in the shield of the RF feed coax and took length to be 0.5m. That yields 4 Amps of ground loop current necessary to produce 100 uN in the Earth's field.
It would be a wise precaution to run this experiment inside Helmholtz coils to cancel possible interactions with Earth's magnetic field.
So yeah - except that reversing the test article pretty much reverses the thrust and does NOT reverse your Lorentz force. So I think it's unnecessary.
No and no. That 10 Amps is main current, not residual ground loop current . Reversing the test article leaves the coax feed exiting in the same place, so also no.
Latest paper by Dr. White, on http://ntrs.nasa.gov/ , exploring the idea of the quantum vacuum not being an absolute immutable and nondegradable state, and examining some rami cations of the quantum vacuum being able to support non-trivial spatial variations in density. They claim that their "considerations showed no predictions that were contrary to observation, and in fact duplicated predictions for energy states associated with the primary quantum number."
http://hdl.handle.net/2060/20150006842
Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom
Harold White, Jerry Vera,y Paul Bailey,z Paul March,x Tim Lawrence,{ Andre Sylvester, and David Brady
NASA Johnson Space Center
2101 NASA Parkway, Houston, TX 77058
(Dated: April 2, 2015)
Publication Date: Apr 02, 2015
Document ID:
20150006842 (Acquired Apr 28, 2015)
Subject Category: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ATOMIC AND MOLECULAR PHYSICS; NUMERICAL ANALYSIS; COMPUTER PROGRAMMING AND SOFTWARE
Report/Patent Number: JSC-CN-33080
Document Type: Technical Report
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 9p; In English
There is an error in the integration of equation 11. Apparently their "simple enough" integration was not simple enough!
QuoteRodal:
Interestingly (for this thread's discussion due to the significance that the NASA experimenters have placed on the dielectric being responsible for providing the measured thrust) is what happens in the High Density PolyEthylene (HDPE) dielectric polymer insert. Because the dimensions of the dielectric are not negligible compared to the EM Drive's dimension, and the dielectric is not modeled as just a boundary condition.
The loss tangent of HDPE is reported to be
tan delta = 0.0004
Therefore the intrinsic impedance angle is
intrinsic impedance angle =(ArcTan[0.0004])/2
Therefore, inside the HDPE dielectric the electric and magnetic fields, instead of being out of phase by 90 degrees (as they are in the air or vacuum medium), will be out of phase by:
90 - (ArcTan[0.0004])/2 = 89.9998 degrees
This phase angle (89.9998 degrees) will show practically no visual difference with 90 degrees at the resolution of the following image :
Mr Rodal can you advise me on the value .0004 in your work above, is that in degrees or radians or just a figure that one simply takes the arctan of. Im trying to use the "bc" program in linux command line to get a grip on the overall topic, and bc reports results in radians, hence the requirement to do a 180/pi conversion.
echo "scale=20; 90 - (a(0.0004)/2)*(180/(4*a(1)))" | bc -l
89.98854084470853845905
Thanks
arc
Im seeing an overlap between this kind of work and work done by T.T.Brown...
anyone care to briefly comment on it?
(Incase your unfamiliar with T.T. Brown, he discovered Biefeld-Brown effect, but also discovered another force that he insisted was NOT biefeld-brown effect (ion wind), also he believed the dielectric played a primary role in the force, and that a reaction force existed on "all solid material bodies making up the physical environment")
He makes some very peculiar statements in his 1929 article, which lead me to believe he was an honest experimenter (ofcourse he explains in terms of what people knew in the 1920's)
the 1929 article & gravitator patent: http://www.rexresearch.com/gravitor/gravitor.htm#patent
This patent strikes me the most (attached): US3187206 (1965),
He has a Half-Wave Radiator, tapered dielectric member etc...
please tell me what you think because im seeing a fair bit of crossover.
I seriously think there is something to be gleaned from TTBrown's work.
Regards.
PS: Im thoroughly enjoying the thread, wish i was as up to speed as you lot. 8)
Im seeing an overlap between this kind of work and work done by T.T.Brown...
anyone care to briefly comment on it?
(Incase your unfamiliar with T.T. Brown, he discovered Biefeld-Brown effect, but also discovered another force that he insisted was NOT biefeld-brown effect (ion wind), also he believed the dielectric played a primary role in the force, and that a reaction force existed on "all solid material bodies making up the physical environment")
He makes some very peculiar statements in his 1929 article, which lead me to believe he was an honest experimenter (ofcourse he explains in terms of what people knew in the 1920's)
the 1929 article & gravitator patent: http://www.rexresearch.com/gravitor/gravitor.htm#patent
This patent strikes me the most (attached): US3187206 (1965),
He has a Half-Wave Radiator, tapered dielectric member etc...
please tell me what you think because im seeing a fair bit of crossover.
I seriously think there is something to be gleaned from TTBrown's work.
Regards.
PS: Im thoroughly enjoying the thread, wish i was as up to speed as you lot. 8)
Asymmetrical Capacitors for Propulsion : http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040171929.pdf
Conclusions: "... In spite of decades of speculation about possible new physical principles being responsible for the thrust produced by ACTs and lifters, we find no evidence to support such a conclusion. On the contrary, we find that their operation is fully explained by a very simple theory that uses only
electrostatic forces and the transfer of momentum by multiple collisions. ".
My understanding is that for emDrive, the new tests were successfully performed in a (close to) vacuum.
QuoteRodal:
Interestingly (for this thread's discussion due to the significance that the NASA experimenters have placed on the dielectric being responsible for providing the measured thrust) is what happens in the High Density PolyEthylene (HDPE) dielectric polymer insert. Because the dimensions of the dielectric are not negligible compared to the EM Drive's dimension, and the dielectric is not modeled as just a boundary condition.
The loss tangent of HDPE is reported to be
tan delta = 0.0004
Therefore the intrinsic impedance angle is
intrinsic impedance angle =(ArcTan[0.0004])/2
Therefore, inside the HDPE dielectric the electric and magnetic fields, instead of being out of phase by 90 degrees (as they are in the air or vacuum medium), will be out of phase by:
90 - (ArcTan[0.0004])/2 = 89.9998 degrees
This phase angle (89.9998 degrees) will show practically no visual difference with 90 degrees at the resolution of the following image :
Mr Rodal can you advise me on the value .0004 in your work above, is that in degrees or radians or just a figure that one simply takes the arctan of. Im trying to use the "bc" program in linux command line to get a grip on the overall topic, and bc reports results in radians, hence the requirement to do a 180/pi conversion.
echo "scale=20; 90 - (a(0.0004)/2)*(180/(4*a(1)))" | bc -l
89.98854084470853845905
Thanks
arc
Consider the following EM Drive design:
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide. By targeting the slowest wave velocity, we are maximizing the amount of stored electromagnetic momentum for a given amount electromagnetic energy.
p = E/v, where v << c inside the waveguide.
E = P*t, energy is power in x time (assuming a lossless cavity)
2nd component: We need a frustum that matches the diameter of the resonant chamber "at the small end" and slowly expands to a TBD length and diameter. As the waveguide expands, the wavelength will be increasing proportional to the increasing wave velocity. We want it to expand to near it's free space value.
3rd component: We need a partial reflector, between the two, so that we can have resonance in one chamber, and thrust in the other. Like a laser.
Principle of operation:
When the energy stored in the resonant chamber is released into the frustum, it expands due to the increased wave velocity to a longer wavelength before it is reflected. It leaves the "nozzle" with momentum p1, but when it arrives at the reflector, it has momentum p2 << p1, because the wave velocity has increased "significantly".
The reflected waves then travel back into the frustum only to find that due to their increased wavelength, now they don't fit anymore, so they are attenuated. Again, absorbing the momentum into the frustum as heat and kinetic energy in the "forward" direction.
....
....
To put it quantum mechanically:
N photons are injected at momentum p1 = N*h/lambda_1
N photons are reflected at the far end with momentum p2 = N*h/lambda_2
The wavelengths are not equal. Momentum is conserved because the system moves forward. The red-shifted photons are mimicking a gravitational field. They are trying to escape a gravity well, only to be reflected back in and fall back through the event horizon as wave velocity goes to zero. (Sorry I love that analogy!)
Todd Desiato
Such a shame it's so difficult to simply put it in space and check. It would have saved Woodward 20 years and I don't know how many years on this already.Do you think is difficult to put in space?
I speak as someone who watched Apollo 11 on the moon.
Consider the following EM Drive design:
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide. By targeting the slowest wave velocity, we are maximizing the amount of stored electromagnetic momentum for a given amount electromagnetic energy.
p = E/v, where v << c inside the waveguide.
E = P*t, energy is power in x time (assuming a lossless cavity)
2nd component: We need a frustum that matches the diameter of the resonant chamber "at the small end" and slowly expands to a TBD length and diameter. As the waveguide expands, the wavelength will be increasing proportional to the increasing wave velocity. We want it to expand to near it's free space value.
3rd component: We need a partial reflector, between the two, so that we can have resonance in one chamber, and thrust in the other. Like a laser.
Principle of operation:
When the energy stored in the resonant chamber is released into the frustum, it expands due to the increased wave velocity to a longer wavelength before it is reflected. It leaves the "nozzle" with momentum p1, but when it arrives at the reflector, it has momentum p2 << p1, because the wave velocity has increased "significantly".
The reflected waves then travel back into the frustum only to find that due to their increased wavelength, now they don't fit anymore, so they are attenuated. Again, absorbing the momentum into the frustum as heat and kinetic energy in the "forward" direction.
To put it quantum mechanically:
N photons are injected at momentum p1 = N*h/lambda_1
N photons are reflected at the far end with momentum p2 = N*h/lambda_2
The wavelengths are not equal. Momentum is conserved because the system moves forward. The red-shifted photons are mimicking a gravitational field. They are trying to escape a gravity well, only to be reflected back in and fall back through the event horizon as wave velocity goes to zero. (Sorry I love that analogy!)
Todd Desiato
Excellent. This makes to me much more engineering/scientific sense than the closed cavity design pioneered by Shawyer and imitated in the US and Chinese laboratories.
So it looks to me that either the UK/US/Chinese measurements are an artifact, or if they are real (*), the design you sketched above should produce more thrust than the present designs.
___
(*) if they are real, I would like to summarize the present understanding regarding the energy paradox. I thought you had reached a common conclusion but @frobnicat raised apparently new points that apparently still need to be addressed ?
Yes, I added:
Where would the Q factor enter into consideration?
(Without the Q into the thrust force equation, we still have an inefficient photon rocket)
[and when one enters the Q factor for a closed cavity, I yet have to embrace an explanation for a closed cavity where I can fully see conservation of momentum and conservation of energy satisfied. For example, Shawyer only takes into account the forces perpendicular to the bases and neglects the counterbalancing forces from the conical surface which result in zero net thrust force]
Ditto for the GR calculation: they are one-dimensional longitudinal approximations, where the index of refraction changes in the longitudinal direction: but the truncated cone is 3-D and has counterbalancing forces due to the forces on the conical surface which cancel the thrust
If I'm wrong, I would like someone to show what happens with the forces on the conical surface (which are at an angle to the longitudinal direction)
I need a free-body diagram showing the force vectors on all the copper surfaces for the 3-D problem force summation :)
Another issue: my understanding of your derivation is that it follows from the expression for the cylindrical cavity (cone angle = zero): hence it is a constant cross-section longitudinal approximation to the cone, where the index of refraction changes in the longitudinal direction: but the truncated cone is 3-D and has counterbalancing forces due to the forces on the conical surface which cancel the thrustYes, I added:
Where would the Q factor enter into consideration?
(Without the Q into the thrust force equation, we still have an inefficient photon rocket)
[and when one enters the Q factor for a closed cavity, I yet have to embrace an explanation for a closed cavity where I can fully see conservation of momentum and conservation of energy satisfied. For example, Shawyer only takes into account the forces perpendicular to the bases and neglects the counterbalancing forces from the conical surface which result in zero net thrust force]
Ditto for the GR calculation: they are one-dimensional longitudinal approximations, where the index of refraction changes in the longitudinal direction: but the truncated cone is 3-D and has counterbalancing forces due to the forces on the conical surface which cancel the thrust
If I'm wrong, I would like someone to show what happens with the forces on the conical surface (which are at an angle to the longitudinal direction)
I need a free-body diagram showing the force vectors on all the copper surfaces for the 3-D problem force summation :)
The Q only enters in the case of a gravitational interaction through its role in calculating the number of photons (Total mass/energy) in the cavity. If it was a Newtonian momentum interaction only the Power enters. (I get zero when I try Newtonian)
Like this ?
http://upload.wikimedia.org/wikipedia/commons/thumb/9/93/Horn_loudspeaker_animation.gif/250px-Horn_loudspeaker_animation.gif
As I understand there are 2 possible setups: closed (tested) and open (one amateur video on youtube with kitchen microwave magnetron).The problem is that I can hear music from an open speaker (a "waveguide") but I cannot hear anything out of a speaker that is a closed cavity, such that all internal surfaces are perfectly reflective (the closed cavity of the EM Drive).
Regardless of the closed/open structure, shouldn't the cavity have form a reversed parabolic shape?
With the microwave injecting module on its side or in the middle, the reversed parabolic shape will send more microwaves in the required direction.
(http://s7.postimg.org/d9kdplu63/resonatingspeaker.jpg)
In my opinion the engine resembles a very stiff speaker calculated for resonance frequency of 2,45MHz. The stiffer the material the better it resonates in this frequency. It's not only the Q that matters. That may be the reason the Cannae engine has lower efficiency - it is made of thinner metal that is less stiff.
I propose 4 options, as in the picture (A,B,C,D).
Another issue: my understanding of your derivation is that it follows from the expression for the cylindrical cavity (cone angle = zero): hence it is a constant cross-section longitudinal approximation to the cone, where the index of refraction changes in the longitudinal direction: but the truncated cone is 3-D and has counterbalancing forces due to the forces on the conical surface which cancel the thrustYes, I added:
Where would the Q factor enter into consideration?
(Without the Q into the thrust force equation, we still have an inefficient photon rocket)
[and when one enters the Q factor for a closed cavity, I yet have to embrace an explanation for a closed cavity where I can fully see conservation of momentum and conservation of energy satisfied. For example, Shawyer only takes into account the forces perpendicular to the bases and neglects the counterbalancing forces from the conical surface which result in zero net thrust force]
Ditto for the GR calculation: they are one-dimensional longitudinal approximations, where the index of refraction changes in the longitudinal direction: but the truncated cone is 3-D and has counterbalancing forces due to the forces on the conical surface which cancel the thrust
If I'm wrong, I would like someone to show what happens with the forces on the conical surface (which are at an angle to the longitudinal direction)
I need a free-body diagram showing the force vectors on all the copper surfaces for the 3-D problem force summation :)
The Q only enters in the case of a gravitational interaction through its role in calculating the number of photons (Total mass/energy) in the cavity. If it was a Newtonian momentum interaction only the Power enters. (I get zero when I try Newtonian)
It seems that the forces on the conical surfaces of the cone are being ignored, and if one takes into account the forces on the cone surface, the "thrust" would be nullified: no thrust.
Hence the only possible thrust is with a dielectric (either in the cylinder or in the truncated cone).
Is that correct ?
....
You are too fast for my old fingers...
Ultimately, what needs to be shown here is that the "covariant force vector equal to zero" on a photon in the accelerated frame is the same vector in the cavity rest frame (ie. can be transformed to) such that the force on a photon in the rest frame is a result of the (velocity) dispersion due to the shape of the cavity boundary conditions. That transformation would show that the effect is to be expected under General Relativity.
The Q only enters in the case of a gravitational interaction through its role in calculating the number of photons (Total mass/energy) in the cavity. If it was a Newtonian momentum interaction only the Power enters. (I get zero when I try Newtonian for the reasons you have mentioned)
Note: I should probably use "Classical" instead of "Newtonian" but I think you would get the idea that we are looking at the 4-volume as an invariant rather than an integration over the surface of the boundary conditions of classical momentum exchange. That can apply as the summation of the (false gravitational?, ie. frame-dependent) forces on the individual photons to give the resultant force on the cavity.
....
You are too fast for my old fingers...
Ultimately, what needs to be shown here is that the "covariant force vector equal to zero" on a photon in the accelerated frame is the same vector in the cavity rest frame (ie. can be transformed to) such that the force on a photon in the rest frame is a result of the (velocity) dispersion due to the shape of the cavity boundary conditions. That transformation would show that the effect is to be expected under General Relativity.
The Q only enters in the case of a gravitational interaction through its role in calculating the number of photons (Total mass/energy) in the cavity. If it was a Newtonian momentum interaction only the Power enters. (I get zero when I try Newtonian for the reasons you have mentioned)
Note: I should probably use "Classical" instead of "Newtonian" but I think you would get the idea that we are looking at the 4-volume as an invariant rather than an integration over the surface of the boundary conditions of classical momentum exchange. That can apply as the summation of the (false gravitational?, ie. frame-dependent) forces on the individual photons to give the resultant force on the cavity.
I very much appreciate the explanation, unfortunately, I may not be able to understand this until I see the explicit mathematical formula for the 4-volume invariant, particularly the derivation of that invariant :)
Unfortunately, I cannot do it intuitively as you can.
The problem is that I can hear music from an open speaker (a "waveguide") but I cannot hear anything out of a speaker that is a closed cavity, such that all internal surfaces are perfectly reflective (the closed cavity of the EM Drive).
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
...Than maybe the magnetic field of the microwaves resonating inside the cavity "pushes" against the magnetic field of Earth. ...If you believe Shawyer's experiments to not be artifacts, the effect of the Earth's magnetic field was nullified by the fact that Shawyer claims to have tested the EM Drive UP, DOWN, and HORIZONTALLY oriented, measuring the same thrust/PowerInput :(
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
In the EM Drive design I proposed, we want the Q in the resonant cavity to be very high, but we do not want a high Q in the frustum. We want the backward-moving waves to expand, and the reflected waves moving forward to be attenuated. So we want a low Q, high attenuation in the frustum.
Todd
The problem is that I can hear music from an open speaker (a "waveguide") but I cannot hear anything out of a speaker that is a closed cavity, such that all internal surfaces are perfectly reflective (the closed cavity of the EM Drive).
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
All right. Than maybe the magnetic field of the microwaves resonating inside the cavity "pushes" against the magnetic field of Earth. Anyway, the reversed parabolic (speaker-like) shape may send more waves to the wide end.
Whatever the reason it moves, all I am saying is that it has to be tested. Not only for different Q, but also different shapes, different MW injection positions and different stiffness of the 'emiting' structure.
May also be useful to look at how microwaves actually propagate in a cone, and different other shapes, as in the literature of radar, according to Maxwell's equations instead of acoustic waves.
The problem is that I can hear music from an open speaker (a "waveguide") but I cannot hear anything out of a speaker that is a closed cavity, such that all internal surfaces are perfectly reflective (the closed cavity of the EM Drive).
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
All right. Than maybe the magnetic field of the microwaves resonating inside the cavity "pushes" against the magnetic field of Earth. Anyway, the reversed parabolic (speaker-like) shape may send more waves to the wide end.
Whatever the reason it moves, all I am saying is that it has to be tested. Not only for different Q, but also different shapes, different MW injection positions and different stiffness of the 'emiting' structure.
Chapter 9 of Acoustics: Sound Fields and Transducers By Leo L. Beranek, Tim J. Mellow is dedicated to properties of Horn loudspeakers and studies different shapes (hyperbolic, conical, parabolic... finite / infinite) and provides many nice formulas that could stimulate your thinking.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The Mexican hat potential is a good place to start, I think, but not sure yet. It seems reasonable because it might coalesce with symmetry breaking.
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
In the EM Drive design I proposed, we want the Q in the resonant cavity to be very high, but we do not want a high Q in the frustum. We want the backward-moving waves to expand, and the reflected waves moving forward to be attenuated. So we want a low Q, high attenuation in the frustum.
Todd
I see the need for:
*low Q
*high attenuation
(This maybe confirmed by the Chinese: Prof. Yang measured the highest thrust, and the highest thrust/PowerInput, using a Q~1500 (*) much lower than the other researchers)
in the truncated cone, but this is the complete opposite of what is claimed by Shawyer.
Actually Shawyer is proceeding in the completely opposite direction:
1) a superconducting truncated cone with Q>10^6 and
2) Shawyer threw away the dielectric, hence NO attenuation from the dielectric.
3) Also Shawyer increased the cone angle from 10 degrees to 35 degrees, which decreased the geometrical attenuation by a large factor.
How do you reconcile Shawyer going in the completely opposite direction ????
****On the other hand, we have not seen Shawyer flying around with his superconducting EM Drive, and he hasn't reported any results in 6 months. Companies are eager to publicize major positive breakthroughs as soon as possible, particularly when owning Intellectual Property, as patents suffer from exponentially decaying value with time, like long options, so you want to exercise their value as soon as possible ****
____________
(*) Readers just looking at the translation from the Chinese Paper: notice that the Q in the tables are computed by a very unorthodox method. The Q of the Chinese experiments, calculated in the same way as in the West is very low
....
FYI: Marco's 1st draft paper went out on an email today from Paul M. and was distributed to about 35 individuals, including myself to my surprise. A swath of replies went back and forth, including a copy and paste of one of our posts here, between Dr. Rodal and myself. The comments were not constructive, as both Jack S. and Eric D. discarded the notion of gravity in the frustum, because GR would require overcoming the G/c^4 factor.
What these Dr's are missing is that we are not effecting the full spectrum from long wavelength RF to high energy quarks with what is happening in the frustum. It is only mimicking what gravity does in a very narrow bandwidth of the EM spectrum. The factor G/c^4 is only applicable for gravity that affects the FULL bandwidth of all energy and particles. G/c^4 comes from the integral over all modes in the field. We are not affecting all modes, just a few in a relatively low energy regime.
That's IMO of course.
Todd
this is a reference to NASA's experiments with an interferometer, where the laser beam goes through small portholes on a pillbox shaped cylindrical EM Drive cavity.
It is my understanding that NASA has not measured any thrust forces from this experiment involving a pillbox shaped EM Drive cavity.
NASA expected no significant thrust either, because the pillbox-shaped cavity is entirely symmetric in the longitudinal direction (parallel to the laser beam) and because the cavity did not contain any polymer dielectric insert in the experiments (as so far performed).
I would like to remember that White is not using exotic matter at all. Rather, he is working with strong RF fields to try to develop a warp bubble. This was stated here even if implicitly. Finally, an EmDrive device has been properly described here. Using strong external fields to modify locally a space-time has been described here.
If this will be confirmed in the next few months, it will represent a major breakthrough in experimental general relativity since Eddington confirmed the bending of light near the sun. Applications would follow if this idea will appear scalable but it will be a shocking result anyway. We look forward to hear from White very soon.
Marco Frasca (2005). Strong coupling expansion for general relativity Int.J.Mod.Phys.D15:1373-1386,2006 arXiv: hep-th/0508246v3
What if the photon rocket utilized the same construction with a cavity that would make the light move slower?
http://news.harvard.edu/gazette/1999/02.18/light.html
As it is possible to slow the light, then the lower its speed the bigger its thrust.
That's one thing. The other is that the thrust is multiplied by the number of bounccs.
That applies to MW waves in the resonating cavity. Hence - the bigger the number of bounces, the bigger the thrust.
You can actually amplify the photon rocket thrust as well.
...
In my opinion the engine resembles a very stiff speaker calculated for resonance frequency of 2,45MHz. The stiffer the material the better it resonates in this frequency. It's not only the Q that matters. That may be the reason the Cannae engine has lower efficiency - it is made of thinner metal that is less stiff.
...
The problem is that I can hear music from an open speaker (a "waveguide") but I cannot hear anything out of a speaker that is a closed cavity, such that all internal surfaces are perfectly reflective (the closed cavity of the EM Drive).
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
All right. Than maybe the magnetic field of the microwaves resonating inside the cavity "pushes" against the magnetic field of Earth. Anyway, the reversed parabolic (speaker-like) shape may send more waves to the wide end.
Whatever the reason it moves, all I am saying is that it has to be tested. Not only for different Q, but also different shapes, different MW injection positions and different stiffness of the 'emiting' structure.
....
FYI: Marco's 1st draft paper went out on an email today from Paul M. and was distributed to about 35 individuals, including myself to my surprise. A swath of replies went back and forth, including a copy and paste of one of our posts here, between Dr. Rodal and myself. The comments were not constructive, as both Jack S. and Eric D. discarded the notion of gravity in the frustum, because GR would require overcoming the G/c^4 factor.
What these Dr's are missing is that we are not effecting the full spectrum from long wavelength RF to high energy quarks with what is happening in the frustum. It is only mimicking what gravity does in a very narrow bandwidth of the EM spectrum. The factor G/c^4 is only applicable for gravity that affects the FULL bandwidth of all energy and particles. G/c^4 comes from the integral over all modes in the field. We are not affecting all modes, just a few in a relatively low energy regime.
That's IMO of course.
Todd
I don't know who Jack S. and Eric D. are. If the letter is in reference to forum posts, I'm glad I had posted this some time ago:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1371241#msg1371241Quote from: Rodalthis is a reference to NASA's experiments with an interferometer, where the laser beam goes through small portholes on a pillbox shaped cylindrical EM Drive cavity.
It is my understanding that NASA has not measured any thrust forces from this experiment involving a pillbox shaped EM Drive cavity.
NASA expected no significant thrust either, because the pillbox-shaped cavity is entirely symmetric in the longitudinal direction (parallel to the laser beam) and because the cavity did not contain any polymer dielectric insert in the experiments (as so far performed).
So if Jack S. and Eric D. (whoever they are) are discussing "the notion of gravity in the frustum" I already pointed out that the Interferometer tests were not conducted with a frustum but instead with a pillbox shaped cylindrical geometry. As to the size of the spacetime distortion everybody is in agreement that one expects it to be extremely small. That's the relevance of Marco Frasca's papers: and why Frasca's papers are so interesting, regarding the appropriate coupling.
QUESTION: In any case what are these people (Jack S. and Eric D. ) so excited about that they are writing about it? What's the harm with Dr. White trying to find out?
As Frasca wrote in his webpage:QuoteI would like to remember that White is not using exotic matter at all. Rather, he is working with strong RF fields to try to develop a warp bubble. This was stated here even if implicitly. Finally, an EmDrive device has been properly described here. Using strong external fields to modify locally a space-time has been described here.
If this will be confirmed in the next few months, it will represent a major breakthrough in experimental general relativity since Eddington confirmed the bending of light near the sun. Applications would follow if this idea will appear scalable but it will be a shocking result anyway. We look forward to hear from White very soon.
Marco Frasca (2005). Strong coupling expansion for general relativity Int.J.Mod.Phys.D15:1373-1386,2006 arXiv: hep-th/0508246v3
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
In the EM Drive design I proposed, we want the Q in the resonant cavity to be very high, but we do not want a high Q in the frustum. We want the backward-moving waves to expand, and the reflected waves moving forward to be attenuated. So we want a low Q, high attenuation in the frustum.
Todd
Note that it is not any more useful than a spring pushing between two points : this is just a way to beam action(force)/reaction(opposite force). In principle this could be used to build a "pillar of light" between ground and a craft rising to orbit (albeit the engineering seems too hard).....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
What if the photon rocket utilized the same construction with a cavity that would make the light move slower?
http://news.harvard.edu/gazette/1999/02.18/light.html
As it is possible to slow the light, then the lower its speed the bigger its thrust.
That's one thing. The other is that the thrust is multiplied by the number of bounccs.
That applies to MW waves in the resonating cavity. Hence - the bigger the number of bounces, the bigger the thrust.
You can actually amplify the photon rocket thrust as well.
See here:
(http://s22.postimg.org/xv4nrzxch/Photon_Thrust_Amplification.jpg)
Source: Wiki, http://upload.wikimedia.org/wikipedia/commons/8/8e/Photon-Thrust-Amplification.jpg
Bend this light path with optical fiber and you receive a powerful thruster.
Like this:
(http://s3.postimg.org/8ajq5b2g3/bentfiber.jpg)
A very simple idea... nobody ever checked it yet, I suppose. I think this setup may be worth checking.
Please consider the fact that it is not c in the nominator, but the actual speed of light in the optical fiber. The slower the speed of the light in this apparatus, the greater the thrust!
The EmDrive works based on similar principle.
....
You are too fast for my old fingers...
Ultimately, what needs to be shown here is that the "covariant force vector equal to zero" on a photon in the accelerated frame is the same vector in the cavity rest frame (ie. can be transformed to) such that the force on a photon in the rest frame is a result of the (velocity) dispersion due to the shape of the cavity boundary conditions. That transformation would show that the effect is to be expected under General Relativity.
The Q only enters in the case of a gravitational interaction through its role in calculating the number of photons (Total mass/energy) in the cavity. If it was a Newtonian momentum interaction only the Power enters. (I get zero when I try Newtonian for the reasons you have mentioned)
Note: I should probably use "Classical" instead of "Newtonian" but I think you would get the idea that we are looking at the 4-volume as an invariant rather than an integration over the surface of the boundary conditions of classical momentum exchange. That can apply as the summation of the (false gravitational?, ie. frame-dependent) forces on the individual photons to give the resultant force on the cavity.
I very much appreciate the explanation, unfortunately, I may not be able to understand this until I see the explicit mathematical formula for the 4-volume invariant, particularly the derivation of that invariant :)
Unfortunately, I cannot do it intuitively as you can.
That would, of course, constitute a proof.
....
And if you open the big base of the EM Drive cavity, so that it becomes a speaker, then it is a very inefficient photon rocket, and therefore the claims of Shawyer don't make sense because they are thousands of time greater thrust per input power than a photon rocket :'(
I need to study @notsosureofit's GR calculation, but I think the point that is being missed here is, the resonant cavity acts as an EM Momentum amplifier. The Q factor comes in not "Just" as the number of photons stored, but also; In GR as in PV, as the energy density inside the cavity increases, the wave velocity decreases. As velocity decreases, momentum increases. That "effective mass" of the photons in the cavity kicks in stronger.
p ~ E/v and in the cavity v << c
This makes it a not-so "inefficient" photon rocket!
In the EM Drive design I proposed, we want the Q in the resonant cavity to be very high, but we do not want a high Q in the frustum. We want the backward-moving waves to expand, and the reflected waves moving forward to be attenuated. So we want a low Q, high attenuation in the frustum.
Todd
Sorry if this was already stated but, what is quantitatively the energy density inside the cavity (with a given Q of say, 10000) ? And how much quantitatively the wave velocity would decrease due to this energy density ? According to strict and uncontroversial interpretation of GR ?
Apologies for the delay. Requested link here:Mathematica looks interesting but maybe later as I suspect there would be a learning curve.....Yes I have calculated it, but it is a Mathematica program, not an Excel spreadsheet. I posted (earlier in the thread) comparisons of the measurements vs. predictions using Shawyer's and McCulloch's formulas.
Did you or anyone else ever write an excel spreadsheet to calc Shawyers Design Factor? If so pls link it or if not please consider doing it as your skills there are much better than mine.
You may want to PM @aero to ask whether he did it with Excel (if my memory is correct @aero also calculated Shawyer's Design Factor, as I recall having exchanges in this forum with him).
And of course, when running your program, you will first check your results vs. Shawyer's published Design Factor results, etc., to make sure that your program is correct.
Is this still your Design Factor equation?
Thanks for your assistance. Most appreciated.
(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829379;image)
I recognize that equation is my Mathematica-writing, but I need a link to the message where I posted it, in order to remember the context. Too long ago :)
I did, but the Excel file is not suitable for distribution, having all of my work scattered throughout a 500 line file with little or no embedded explanations. That is, it's un-usable even for me, without considerable time discovering what I intended to do. For example, here is my design factor, Df, equations. I think the variables are:
Lo - length
Lg1-diameter
Lg2-diameter
Df = 0.844 Df=S_o*Lo((1/Lg1) - (1/lg2)) where S_o = (1-(Lo^2/(Lg1*Lg2)))^-1
Combining Df = Lo*( 1 - (Lo^2/(Lg1*Lg2)))^-1 *((1/Lg1)-(1/Lg2))
Edit: I used to have
Penrose, Roger (1965). "A remarkable property of plane waves in general relativity". Rev. Mod. Phys. 37: 215–220. Bibcode:1965RvMP...37..215P. doi:10.1103/RevModPhys.37.215
around here somewhere, I'll look.
And regarding Shawyer's design factor, I did program Dr. Rodel's equation and did match his numbers but it was some time ago and is now lost in the fog of the past.Is ok. Will recreate the Design Factor excel spreadsheet and post to the WiKi for all to use. Will never be lost again.
Edit: I used to have
Penrose, Roger (1965). "A remarkable property of plane waves in general relativity". Rev. Mod. Phys. 37: 215–220. Bibcode:1965RvMP...37..215P. doi:10.1103/RevModPhys.37.215
around here somewhere, I'll look.
Amazing ! Found it after all these years. I have to re-read and re-understand it of course, but check Fig. 1. "The sandwich wave" where you have a section of curved space-time sandwiched between flat. That alone is closer to this situation than anything I've seen so far.
The previous article, Rosen, Joe. "Embedding of Various Relativistic Riemannian Spaces in Pseudo-Euclidean Spaces" contains tables of transforms. That could prove invaluable !
Consider the following EM Drive design:
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide. By targeting the slowest wave velocity, we are maximizing the amount of stored electromagnetic momentum for a given amount electromagnetic energy.
p = E/v, where v << c inside the waveguide.
E = P*t, energy is power in x time (assuming a lossless cavity)
2nd component: We need a frustum that matches the diameter of the resonant chamber "at the small end" and slowly expands to a TBD length and diameter. As the waveguide expands, the wavelength will be increasing proportional to the increasing wave velocity. We want it to expand to near it's free space value.
...
Its great to see continuing discussions on this emdrive forum. There are Theorists and there are Observers. I tend to fall into the latter category and appreciate all those willing to build their own test articles, sharing plans & results. Onwards and upwards...There are also Replicators / Builders here ;)
Consider the following EM Drive design:
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide. By targeting the slowest wave velocity, we are maximizing the amount of stored electromagnetic momentum for a given amount electromagnetic energy.
p = E/v, where v << c inside the waveguide.
E = P*t, energy is power in x time (assuming a lossless cavity)
2nd component: We need a frustum that matches the diameter of the resonant chamber "at the small end" and slowly expands to a TBD length and diameter. As the waveguide expands, the wavelength will be increasing proportional to the increasing wave velocity. We want it to expand to near it's free space value.
...
Is this design analogous to the "Modified Aluminum Cavity for TE011 Mode Resonance" previously presented by Paul March? Note, there appears to be two chambers separated by a 1/16" plate (aluminum?). As an avid follower of this thread I have not noticed any comments about this dual chamber design. However, I could be misinterpreting the attached image.
This has been a truly fascinating discussion which has never ceased capturing my attention. I feel fortunate to passively witness. Thank you all, especially the replicators.
-Matthew Trimble
According to Paul March, this is the cavity EW will be using to do a more formal replication of Shawyer and the Chinese using Shawyers Teeter Totter balance beam, which I assume means operation in a vertical orientation.Consider the following EM Drive design:
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide. By targeting the slowest wave velocity, we are maximizing the amount of stored electromagnetic momentum for a given amount electromagnetic energy.
p = E/v, where v << c inside the waveguide.
E = P*t, energy is power in x time (assuming a lossless cavity)
2nd component: We need a frustum that matches the diameter of the resonant chamber "at the small end" and slowly expands to a TBD length and diameter. As the waveguide expands, the wavelength will be increasing proportional to the increasing wave velocity. We want it to expand to near it's free space value.
...
Is this design analogous to the "Modified Aluminum Cavity for TE011 Mode Resonance" previously presented by Paul March? Note, there appears to be two chambers separated by a 1/16" aluminum plate. As an avid follower of this thread I have not noticed any comments about this dual chamber design. However, I could be misinterpreting the attached image.
This has been a truly fascinating discussion which has never ceased capturing my attention. I feel fortunate to passively witness. Thank you all, especially the replicators.
-Matthew Trimble
QuoteBend this light path with optical fiber and you receive a powerful thruster.
Like this:
(http://s3.postimg.org/8ajq5b2g3/bentfiber.jpg)
A very simple idea... nobody ever checked it yet, I suppose. I think this setup may be worth checking.
Please consider the fact that it is not c in the nominator, but the actual speed of light in the optical fiber. The slower the speed of the light in this apparatus, the greater the thrust!
The EmDrive works based on similar principle.
I'm sorry but to "bend" the light 180° around like that is equivalent in terms of momentum exchange to just bouncing it : in your above drawing the fibre bundle would receive 2F to the right from this momentum exchange. The total force on an isolated rigid craft would still be 0, as in the first drawing.
...
Photons are in a different frame of reference. The above system should move to the left.
The above system as well as EmDrive is like a cavity with an externally attached pendulum. The pendulum's ball (represents light wave or microwave) bounces in it. And moves the light/MW cavity to the side where it bounces the most.
For the same reason the MW cavity shouldn't exert any directional force.
But it does.
And if so, then probably/maybe a similarly built light cavity with large mirrors on one side and bent optical fiber or small mirror on the other side should produce thrust as well.
The number of light bounces (mirror reflectance) would then represent the photonic thrust multiplication factor similar to Q in EmDrive thrust formula devised by Shawyer.
---
Another issue: why not use Peltier element to cool the superconducting cavity instead of liquid gas?
The vehicle will need electric power anyway, so why add heavy liquid hydrogen reservoir?
The additional electric energy for Peltier cooling shouldn't require as much mass and space as the hydrogen.
It may be economical even for satellites, because the large increase in Q and resulting smaller required input power and smaller engine size would justify additional Peltier module.
Please kindly excuse me if this is an incorrect way of thinking for some reason I am not aware of.
Because Peltier effect can't quite reach cryogenic temperatures, for some thermodynamic reason I forgot. Maybe it changed with recent progress on the subject ? Please inquire : what are the limits of low temp. with Peltier effect, now and tomorrow ? Isn't the Peltier effect still quite low in efficiency ?
Spacetime has stiction? Say it ain't so! ::)
Interesting that breaking CofM means that translational invariance dies, and breaking Einstein's SR core principle means that inertial frame invariance dies. Interesting because you may notice that one is essentially the time derivative of the other. And further that breaking CofE means that time invariance dies.
Perhaps that's a deep observation, but I'm not smart enough to know what it means. All I know is that, for a propellantless propulsor, we are forced to choose between killing off one or the other. If we got creative we could kill off both, maybe!
I'm sure my physics friends down the pub here in Cupertino would simply shrug and say that, since momentum appears not be conserved in the first place, there's ample room for odd statements to be correspondingly made about energy conservation (and I have made them here on this forum).
Perhaps there's an exit route out of this bind via playing off conservation of momentum against conservation of energy. Just a wild thought.
1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide.
Is this design analogous to the "Modified Aluminum Cavity for TE011 Mode Resonance" previously presented by Paul March? Note, there appears to be two chambers separated by a 1/16" plate (aluminum?). As an avid follower of this thread I have not noticed any comments about this dual chamber design. However, I could be misinterpreting the attached image.
This has been a truly fascinating discussion which has never ceased capturing my attention. I feel fortunate to passively witness. Thank you all, especially the replicators.
-Matthew Trimble
Recall that Shawyer defines the Thrust force as:Apologies for the delay. Requested link here:Mathematica looks interesting but maybe later as I suspect there would be a learning curve.....Yes I have calculated it, but it is a Mathematica program, not an Excel spreadsheet. I posted (earlier in the thread) comparisons of the measurements vs. predictions using Shawyer's and McCulloch's formulas.
Did you or anyone else ever write an excel spreadsheet to calc Shawyers Design Factor? If so pls link it or if not please consider doing it as your skills there are much better than mine.
You may want to PM @aero to ask whether he did it with Excel (if my memory is correct @aero also calculated Shawyer's Design Factor, as I recall having exchanges in this forum with him).
And of course, when running your program, you will first check your results vs. Shawyer's published Design Factor results, etc., to make sure that your program is correct.
Is this still your Design Factor equation?
Thanks for your assistance. Most appreciated.
(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829379;image)
I recognize that equation is my Mathematica-writing, but I need a link to the message where I posted it, in order to remember the context. Too long ago :)
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1276053#msg1276053
Aero did reply but his Design Factor equation did not include RfQuoteI did, but the Excel file is not suitable for distribution, having all of my work scattered throughout a 500 line file with little or no embedded explanations. That is, it's un-usable even for me, without considerable time discovering what I intended to do. For example, here is my design factor, Df, equations. I think the variables are:
Lo - length
Lg1-diameter
Lg2-diameter
Df = 0.844 Df=S_o*Lo((1/Lg1) - (1/lg2)) where S_o = (1-(Lo^2/(Lg1*Lg2)))^-1
Combining Df = Lo*( 1 - (Lo^2/(Lg1*Lg2)))^-1 *((1/Lg1)-(1/Lg2))
So before turning either your or Aero's equation to Excel and posting it to the Wiki for all replicators to use, wpuld you please give some feedback on which is correct?
From my trying to follow the Shawyer DF equations, it seems your equation which uses Rf imay be correct?
Would appreciate a set of data variables that I can use to verify my excel equation gives the same results as your Mathematica equation.
As always, thanks for the assistance.
Appreciated.
Hey everyone,
Based on the advice from the forum we have reformulated our experimental design . We have been given permission to use one of the vacuum chambers at Cal Poly which can pull about 1mT using a mechanical pump. By mounting everything on a pendulum we can measure a displacement using a reflected laser. I am not experienced with laser measurements and would greatly appreciate any advice for improving this measurement. With a simple setup it seems we will be able to see 100 mN easily, hopefully this is within reason at powers ~1200 W.
We have also been considering using aluminum for the frustum to minimize the mass of the pendulum. This would coincide with Todd's theory that a lower Q in the frustum is more desirable. We could easily implement a symmetric copper resonant cavity to between the magnetron and the frsutum:1st component: A symmetrical resonator cavity that is optimized to store energy at high Q, and plays no role in thrust. Here, we want to store the lowest order mode that the waveguide can sustain because it has the slowest wave velocity inside the waveguide.
I did some basic solutions for a resonant rectangular chamber and found that to isolate the TE 011 mode at a frequency of 2.4503 GHz we would need a box 7.068 x 7.068 x 12.24 cm. Would we want to match the end of this box to the small end of the frustum?
What should the interface look like?
Perhaps we should keep our experiment simple and introduce this complication later...
Also, does anyone know the dimensions of the aluminum cavity being constructed at Eagleworks? I believe the picture posted is missing a dimension required to solve for the others, or maybe my geometry is lacking.
Is this design analogous to the "Modified Aluminum Cavity for TE011 Mode Resonance" previously presented by Paul March? Note, there appears to be two chambers separated by a 1/16" plate (aluminum?). As an avid follower of this thread I have not noticed any comments about this dual chamber design. However, I could be misinterpreting the attached image.
This has been a truly fascinating discussion which has never ceased capturing my attention. I feel fortunate to passively witness. Thank you all, especially the replicators.
-Matthew Trimble
Hopefully we can use EW's dimensions and not have to worry about FEA.
The electrical connections into the chamber will allow the circuit to be kept outside and connected with slack to a magnetron on the pendulum. I am concerned that the magnetron will overheat quickly due to a lack of convection cooling, but maybe we can run shorter tests to compensate.
Any thoughts?
Glad to see everyone still asking questions and presenting ideas! It is quite an amazing discussion and I look forward to contributing some data.
Kurt Zeller
I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?Although a Google search reveals that this has been brought up before, for example here by @aero: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1275034#msg1275034 there is no entry I could find in the threads as to whether any of the research groups actually used smoke to check air flow. Perhaps others can try separate searches either using their memories or using Google (anything but the poorly functioning "Search" button between "Unread Topics" and "Profile" ;) )
Edit: I used to have
Penrose, Roger (1965). "A remarkable property of plane waves in general relativity". Rev. Mod. Phys. 37: 215–220. Bibcode:1965RvMP...37..215P. doi:10.1103/RevModPhys.37.215
around here somewhere, I'll look.
Amazing ! Found it after all these years. I have to re-read and re-understand it of course, but check Fig. 1. "The sandwich wave" where you have a section of curved space-time sandwiched between flat. That alone is closer to this situation than anything I've seen so far.
The previous article, Rosen, Joe. "Embedding of Various Relativistic Riemannian Spaces in Pseudo-Euclidean Spaces" contains tables of transforms. That could prove invaluable !
An earlier paper, this time by Bondi, on sandwich waves and plane gravitational waves, that, unlike the other ones, has a PDF with a link :):
http://www.itp.kit.edu/~schreck/general_relativity_seminar/Gravitational_waves_in_general_relativity_exact_plane_waves.pdf
Gravitational waves in general relativity
III. Exact plane waves
BY H. BONDI* AND F. A. E. PIRANIt
King's College, London
AND T. ROBINSON
Lately of University College of Wales, Aberystwyth
(Communicated by W H. McCrea, F.R.S.-Received 18 October 1958)
Plane gravitational waves are here defined to be non-flat solutions of Einstein's empty spacetime
field equations which admit as much symmetry as do plane electromagnetic waves,
namely, a 5-parameter group of motions. A general plane-wave metric is written down and
the properties of plane wave space-times are studied in detail. In particular, their characterization
as 'plane' is justified further by the construction of 'sandwich waves' bounded on both
sides by (null) hyperplanes in flat space-time. It is shown that the passing of a sandwich wave
produces a relative acceleration in free test particles, and inferred from this that such waves
transport energy.
As previously pointed out by one of us (Bondi I957), this relative acceleration and
consequent relative velocity prove that gravitational waves transport energy, since
it is in principle possible, utilizing this effect, to construct a device which will extract
energy from a wave. The simplest such device consists of a stiff rod (the rod need not
be rigid in the technical sense, and the difficulties surrounding the consideration of
rigid bodies in relativity theory are not relevant here) and a bead which slides on the
rod with some friction. If the rod lies in a suitable direction transverse to the
direction of wave propagation, and if the bead is at rest relative to the rod at a
position well displaced from the rod's centre of mass, the passing of the wave will
result in some relative motion of the rod and the bead, for in the first approximation
the bead and the mass centre of the rod will each move on a geodesic. This relative
motion will generate heat, and thus locally available energy may be extracted from
the wave.
In these considerations, the effect of the device on the wave has been neglected.
This is a test device-a device constructed out of test particles. Consequently, such
considerations cannot be used to calculate the total amount of available energy in
the wave.
[snip]
...............................................................................
It is clear from the relative acceleration acquired by test particles, as described in sections 3 and 4, that energy
is transferred to test particles by a plane wave, but this does not enable us to make
quantitative assertions about energy transport in general. The present fluid state
of the theory of the energy pseudo-tensor would not appear to justify a discussion of
energy transport in terms of this concept.
Thank you Rodal for replying, I also couldn't find where this simple test was performed. Maybe it could be something tested at a later date?I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?Although a Google search reveals that this has been brought up before, for example here by @aero: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1275034#msg1275034 there is no entry I could find in the threads as to whether any of the research groups actually used smoke to check air flow. Perhaps others can try separate searches either using their memories or using Google (anything but the poorly functioning "Search" button between "Unread Topics" and "Profile" ;) )
Because Peltier effect can't quite reach cryogenic temperatures, for some thermodynamic reason I forgot. Maybe it changed with recent progress on the subject ? Please inquire : what are the limits of low temp. with Peltier effect, now and tomorrow ? Isn't the Peltier effect still quite low in efficiency ?
The Peltier limits are below 100K, which is enough for high-temparature superconductors. The efficiency in such temperature is low, but probably that could be economically viable because of much smaller MW input power and smaller superconducting engine size.
That said, I must sadly admit, that this engine won't probably move in free space. It may move on air cushion though, as in the experiments conducted so far on Earth.
Anyway, if so, then it is at least good for new generation of rotorless helicopters, here on Earth.
Interesting that breaking CofM means that translational invariance dies, and breaking Einstein's SR core principle means that inertial frame invariance dies. Interesting because you may notice that one is essentially the time derivative of the other. And further that breaking CofE means that time invariance dies.
Perhaps that's a deep observation, but I'm not smart enough to know what it means. All I know is that, for a propellantless propulsor, we are forced to choose between killing off one or the other. If we got creative we could kill off both, maybe!
I'm sure my physics friends down the pub here in Cupertino would simply shrug and say that, since momentum appears not be conserved in the first place, there's ample room for odd statements to be correspondingly made about energy conservation (and I have made them here on this forum).
Perhaps there's an exit route out of this bind via playing off conservation of momentum against conservation of energy. Just a wild thought.
I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?
Interesting that breaking CofM means that translational invariance dies, and breaking Einstein's SR core principle means that inertial frame invariance dies. Interesting because you may notice that one is essentially the time derivative of the other. And further that breaking CofE means that time invariance dies.
Perhaps that's a deep observation, but I'm not smart enough to know what it means. All I know is that, for a propellantless propulsor, we are forced to choose between killing off one or the other. If we got creative we could kill off both, maybe!
I'm sure my physics friends down the pub here in Cupertino would simply shrug and say that, since momentum appears not be conserved in the first place, there's ample room for odd statements to be correspondingly made about energy conservation (and I have made them here on this forum).
Perhaps there's an exit route out of this bind via playing off conservation of momentum against conservation of energy. Just a wild thought.
The conundrum may be resolved in two words:
Noether's theorem.
In defining how symmetries are enforced, by extension it reveals where they are not.
Specifically, time-dependent (ie. temporally variant) interactions are, by definition, non-conservative. Although we more commonly encounter such asymmetries in dissipative systems, there are, within electromagnetism at least, non-dissipative non-conservative systems.
And before anyone protests, this isn't half as controversial as it may seem - any electrodynamics textbook will include a section on non-conservative, temporally variant EM interactions. By definition, CoE does not and cannot be applied to them. See Rutherford's first paper ca 1886 on magnetic entropy viscosity (Sv)... in such a delayed response, the time-dependent rise of B to a given H means input and output FxD integrals can be non-equitable, if their mechanical displacements are varied to sub- and super-Sv speeds respectively.
Example: take two permanent magnets, at least one of which has appreciable Sv. Allow them to attract together before B can reach Bmax, obtaining our output FxD integral, then let B peak before separating them against this now-higher force, requiring an appropriately-greater input work integral due to the higher force over the same distance.... we've input more work than the interaction has output! Where'd the energy go? Not dissipated to heat (the magnetocaloric profiles are almost identical, and incidental since net change in B up vs down is equal for both integrals - ie. Sv isn't a direct heating mechanism). Rather, the answer's right there in the setup - the missing energy was spent entirely on displacement against a higher magnetic force. Or, looking at it from the alternative perspective, squandered away by not harvesting it in the first place during the initial delayed-response output displacement.
We can repeat this interaction forever, dumping the same amount of mechanical energy into the vacuum (via the virtual photon exchanges mediating the force) each cycle. Calorimetry will show a continuing loss...
Because Peltier effect can't quite reach cryogenic temperatures, for some thermodynamic reason I forgot. Maybe it changed with recent progress on the subject ? Please inquire : what are the limits of low temp. with Peltier effect, now and tomorrow ? Isn't the Peltier effect still quite low in efficiency ?
The Peltier limits are below 100K, which is enough for high-temparature superconductors. The efficiency in such temperature is low, but probably that could be economically viable because of much smaller MW input power and smaller superconducting engine size.
That said, I must sadly admit, that this engine won't probably move in free space. It may move on air cushion though, as in the experiments conducted so far on Earth.
Anyway, if so, then it is at least good for new generation of rotorless helicopters, here on Earth.
Stirling coolers are used where cryogenic temperatures are required. They are more efficient than Peltier devices. I have used very compact Stirling cooled IR detectors. Several companies make them, It takes about 1 Min. to reduce the temperature of the detector to 95 K, using 1 Watt. However the thermal mass is very tiny. NASA has been investigating Stirling coolers for liquifying rocket fuels (H2, O2) in space and for space telescope applications.
Thank you and I did review of the very nice workup by Dr. Rodal after he pointed it out. It's not only heat convection I was thinking of, but any aberrations in air movement other than the expected thermal currents from the EM device.I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?
That is a very good idea.I don't think it has been suggested before.There was some discussion on convective air flow and the possiblity it may explain the anomalous force measured by EW early in thread 1. However interest in that explanation has dissipated and Dr. Rodal's analysis of thermal-mechanical effects as a conventional explanation has replaced it.
Thank you and I did review of the very nice workup by Dr. Rodal after he pointed it out. It's not only heat convection I was thinking of, but any aberrations in air movement other than the expected thermal currents from the EM device.I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?
That is a very good idea.I don't think it has been suggested before.There was some discussion on convective air flow and the possiblity it may explain the anomalous force measured by EW early in thread 1. However interest in that explanation has dissipated and Dr. Rodal's analysis of thermal-mechanical effects as a conventional explanation has replaced it.
Those who cannot remember the past are condemned to repeat it.
In the first step, we will replicate the original EM-Drive thruster.
It will be driven by a high power RF source (magnetron) which is easily available.
The second step will be a miniaturization by using higher frequencies.
To achieve this, a numerical simulation of the waves inside the cone frustum must be made to obtain the optimal geometry for the cone.
A high frequency generator in the 20-30 GHz range has to be built with the power of a few watts
Thank you and I did review of the very nice workup by Dr. Rodal after he pointed it out. It's not only heat convection I was thinking of, but any aberrations in air movement other than the expected thermal currents from the EM device.I was wondering in your testing did you use a smoke stick also called a smoke pencil to check for air flows around the EM Drive in ambient air conditions?
That is a very good idea.I don't think it has been suggested before.There was some discussion on convective air flow and the possiblity it may explain the anomalous force measured by EW early in thread 1. However interest in that explanation has dissipated and Dr. Rodal's analysis of thermal-mechanical effects as a conventional explanation has replaced it.Quote from: Jorge Ruiz de Santayana "George Santayana"Those who cannot remember the past are condemned to repeat it.
1873 Maxwell derives equations showing that radiation will give rise to stresses on a surface due to the electromagnetic energy density (Maxwells' stress tensor).
1876 Bartoli attempts to measure the radiation pressure on a reflecting surface experimentally but he is unable to overcome disturbing effects due to the heating of the reflecting surface which gives rise to convection currents of air and to the radiometer effect ( https://en.wikipedia.org/wiki/Crookes_radiometer#Explanations_for_the_force_on_the_vanes ), which are collectively described by Bartoli and other scientists of the period, as "gas action."
1900 Lebedew, using light waves is the first person in history to succeed in eliminating these unwanted artifact effects by performing the experiments in a partial vacuum. He used a torsion balance and a highly reflecting mirror in his measurements.
1902 Nichols and Hull made a thorough investigation of the unwanted artifact effects collectively called "gas action" and accurately establish the accuracy of Maxwell's predicted stress tensor. Nichols and Hull also performed experiments in a partial vacuum using a torsion balance and a highly reflecting mirror in their measurements.
1949 Carrara and Lombardini qualitatively demonstrate the existence of radiation pressure at microwave frequencies to the correct order of magnitude, but no quantitative results are obtained. They employ a free wave method, which involves a very difficult refraction problem due to air, which precludes a quantitative assessment.
1950 Cullen is the first person to accurately measure radiation pressure at microwave frequencies. Cullen uses power ranging from 10 to 50 watts in his microwave pressure measurements, at a wavelength of 10 cm, measuring 6.77 microNewtons/kW. Cullen used a torsion balance and a highly reflecting mirror in his measurements. Cullen performed his experiments in ambient air conditions. It was impossible to obtain a stable baseline, even on a relatively short-term basis of a minute's duration. This continual drifting of the baseline was found to be due to air convection currents set up by small and changing temperature gradients within the microwave waveguides. The remedy was to reduce the air resistance of the reflecting end plate so that the convection currents would have no appreciable effect. The reflecting end plate was replaced by a system of concentric wire rings (shown on Fig. 12 of Cullen's paper). The rings acted as an almost perfect reflector of the electromagnetic waves but at the same time had a small effective cross-section to air currents. NASA, Shawyer, Yang, and other EM Drive researchers would be well advised to experiment with replacing the end plates of the EM Drive with this system of concentric rings, in order to address the problem of air convection currents that has plagued radiation pressure experiments in ambient conditions ever since Maxwell 140 years ago. Even in a partial vacuum, if one uses for example bilayer plates of copper/glass-fiber-reinforced epoxy with the reinforced polymer on the external surface, there is the possibility of outgassing in a vacuum producing a false positive. The use of a mesh precludes this problem both in ambient air conditions and in a vacuum.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829135;image)
Attachment: ABSOLUTE POWER MEASUREMENT AT MICROWAVE FREQUENCIES
By A. L. CULLEN, Ph.D., B.Sc.(Eng.), Associate Member.
(published February, 1952.)
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=828862
....Fair point. A detailed discussion of the effect of the ring mesh is not trivial. I refer you to Cullen's discussion of the effect on the pressure measurement (not taking into account Q, because Cullen tested an open waveguide) in Cullen's paper attached in my post above. The effect of a ring mesh has been further understood during the past 65 years, thanks to great advances on numerical calculations.
Dr. Rodal,
How much of effect would the use of a ring (or mesh) have on ohmic losses in the endplate for some of the excited modes tested at EW? Any hunches for the effect on the cavity Q? (i.e. aren't the losses going to be larger for the ring/mesh versus a solid sheet of copper?)
For in-air testing, the use of a ring/mesh makes perfect sense. I'm just curious as to the predicted effect on Q (perhaps neglible?). Engineering is almost always a series of tradeoffs; minimizing a known noise source during delicate force measurements would seem like a much more important design parameter than maximizing Q at this stage.
Thanks,
James
....Fair point. A detailed discussion of the effect of the ring mesh is not trivial. I refer you to Cullen's discussion of the effect on the pressure measurement (not taking into account Q, because Cullen tested an open waveguide) in Cullen's paper attached in my post above. The effect of a ring mesh has been further understood during the past 65 years, thanks to great advances on numerical calculations.
Dr. Rodal,
How much of effect would the use of a ring (or mesh) have on ohmic losses in the endplate for some of the excited modes tested at EW? Any hunches for the effect on the cavity Q? (i.e. aren't the losses going to be larger for the ring/mesh versus a solid sheet of copper?)
For in-air testing, the use of a ring/mesh makes perfect sense. I'm just curious as to the predicted effect on Q (perhaps neglible?). Engineering is almost always a series of tradeoffs; minimizing a known noise source during delicate force measurements would seem like a much more important design parameter than maximizing Q at this stage.
Thanks,
James
Given the fact that the highest measured thrust forces, and the highest measured thrust force/InputPower were obtained with the lowest Q reported (Q~1500 see my notes concerning this) by Prof. Yang in China, while high Q force measurements at NASA Eagleworks have resulted in much lower forces and force/InputPower, a proportional relationship between force and Q remains to be experimentally corroborated (it is actually negated by the Chinese experiments).
Furthermore, the theoretical considerations advanced by Todd in these pages put more emphasis on the attenuation (which may be supported by NASA Eagleworks findings that they only measured thrust forces with an insert polymer dielectric and no forces without it).
Finally, it is not clear that the portion of the Q due to reflection of the low frequencies (larger wavelength) of the resonant microwave spectrum would be impaired by the mesh.
My microwave oven has a conductive metal mesh on the inside of the transparent glass, so that the microwaves are reflected, to prevent microwaves from escaping the microwave.
(http://makeitorfixit.com/wp-content/uploads/2014/01/MicrowaveDoor.jpg.jpg)
BOTTOM LINE: I would suggest for experimenters to try 4 different kinds of ends:
1) A solid reflecting end (copper or aluminum)
2) A ring-wired mesh as used by Cullen
3) A transparent glass (transparent to microwaves)
4) An open end
And compare the results. Such tests would be very valuable both for scientific and engineering purposes to understand what is being measured.
...
1) A solid reflecting end (copper or aluminum)
2) A conductive wire mesh
3) A transparent glass (transparent to microwaves)
4) An open end
And compare the results. Such tests would be very valuable both for scientific and engineering purposes to understand what is being measured.
Quote...
1) A solid reflecting end (copper or aluminum)
2) A conductive wire mesh
3) A transparent glass (transparent to microwaves)
4) An open end
And compare the results. Such tests would be very valuable both for scientific and engineering purposes to understand what is being measured.
Apart for the conductive wire mesh it would seem to me that Shawyer likely tested the other ways (why would you use something when you can use nothing? etc.) and found out that the best results were with a solid reflecting end.
I keep looking at this and thinking it's not right.
It looks to symmetrical.
COMSOL's website says the RF module can do far field calculations, and the antenna placement would appear to put at least part of the frustum in the near field. It looks by eyeball that the software is only looking at the far field being reflecting off the small end of the frustum.
Or am I missing something?
I keep looking at this and thinking it's not right.
(http://i1365.photobucket.com/albums/r745/LASJayhawk/image.jpg1_zpszvfxogt9.jpg) (http://s1365.photobucket.com/user/LASJayhawk/media/image.jpg1_zpszvfxogt9.jpg.html)
It looks to symmetrical.
COMSOL's website says the RF module can do far field calculations, and the antenna placement would appear to put at least part of the frustum in the near field. It looks by eyeball that the software is only looking at the far field being reflecting off the small end of the frustum.
Or am I missing something?
@RodalNo I only posted the graphic results and numerical comparisons. I also posted the output graphics for the Poynting vector (I have not seen anyone else do that, including Greg Egan). Greg Egan posted a solution for constant in the transverse (aximuthal) direction modes, but arbitrary variation in the other directions . Greg Egan's solution will not address the Cyl TM212 being shown above, but it does address other modes like Cyl TE012 that have been discussed, see: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html
Have you posted your exact solution code here?
I have my Mathematica fired up and ready to go!
Can you possibly post your Mathematica notebook?@RodalNo I only posted the graphic results. Greg Egan posted a solution for constant in the transverse (aximuthal) direction modes, but arbitrary variation in the other directions . Greg Egan's solution will not address the Cyl TM212 being shown above, but it does address other modes like TE012 that have been discussed, see: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html
Have you posted your exact solution code here?
I have my Mathematica fired up and ready to go!
And while on the subject of simulation: Guido Fetta of Cannae tells me that his COMSOL(?unsure) sim predicts a nonzero net Lorentz force for his device. Now, we all learned that no closed system of currents can produce such a net force. There's a paradox. He insists that there are no significant cumulative rounding errors.
Anyone have insight into this?
...
BOTTOM LINE: I would suggest for experimenters to try 4 different kinds of ends:
1) A solid reflecting end (copper or aluminum)
2) A conductive wire mesh
3) A transparent glass (transparent to microwaves)
4) An open end
And compare the results. Such tests would be very valuable both for scientific and engineering purposes to understand what is being measured.
Do you know for a fact that Fetta made this elementary blunder, or are you just hypothesising?And while on the subject of simulation: Guido Fetta of Cannae tells me that his COMSOL(?unsure) sim predicts a nonzero net Lorentz force for his device. Now, we all learned that no closed system of currents can produce such a net force. There's a paradox. He insists that there are no significant cumulative rounding errors.Yes. Let's remember that the COMSOL FEA solution is the steady state solution showing the spatial distribution of the field. The harmonic (time varying) part of the field is assumed. So, for example, the Magnetic Field shown on the COMSOL output is the spatial distribution of the magnetic field. Now, what is shown as a maximum and what is shown as a minimum is arbitrary, since depending at what time one arbitrarily chooses to display the magnetic field, as the magnetic field varies with time like a harmonic function.
Anyone have insight into this?
Similarly, the Poynting vector is a harmonic function of time, as you point out, well known in the literature, with a frequency which is twice the frequency of the magnetic and the electric field.
Although the spatial distribution of the Poynting vector is non-zero at arbitrary points in time, over a whole cycle it sums up to exactly zero, just like the mean of the magnetic and electric fields is also zero.
The Poynting vector solution of Maxwell's equations points towards the Big Base half of the time, and points towards the Small Base half of the time.
COMSOL will not tell that to the analyst. The FEA analyst is supposed to know that.
It is recommended that COMSOL and any other packages (ANSYS MultiPhysics, etc., ABAQUS, ADINA, NASTRAN) should be run by experience FEA analysts.
...I don't know the gentleman, and I have no idea as to what he may or may not have done, may have said or may not have said.
Do you know for a fact that Fetta made this elementary blunder, or are you just hypothesising?
Thanks. And we are in violent agreement about the consequences of applying Maxwell.
Yes, but not the sort that is supposed to matter according to Maxwell.Thanks. And we are in violent agreement about the consequences of applying Maxwell.
How about his friend, the demon?
If I pick my waveleghth, design my cavity, and antenna placement, then adjust the phase of the signal such that one end is in a node and the other is riding a crest, both all the time all the time, I would have an unbalance between the two ends???
....There are several people that think the same way (that it cries out for a space test), while there are several other ones that think it would be premature. Since you made a powerful argument for the energy paradox, it would be useful if you could list all the reasons (and what and how should be tested) why a space test should be the next step, as a powerful argument in that direction may help to push the ball rolling...upwards :)
Really and truly, this experiment cries out for a space test.
If enough people here are solidary, we could petition directly to Elon Musk for a ride on a dragon slated for the ISS, and see what he has to say. As collateral we could offer him all the research that has been done and collected by the fine gentlemen and ladies here. That is, IF the device actually works in space. But Elon Musk likes taking chances, that's what made him a billionaire.....There are several people that think the same way (that it cries out for a space test), while there are several other ones that think it would be premature. Since you made a powerful argument for the energy paradox, it would be useful if you could list all the reasons (and what and how should be tested) why a space test should be the next step, as a powerful argument in that direction may help to push the ball rolling...upwards :)
Really and truly, this experiment cries out for a space test.
I am happy that you found my position on the energy paradox powerful. But speaking of premature, some further mulling and reading - ongoing - tells me that there may well be a third possibility for the behaviour of the thrust over time. If this "third thrust scenario" turns out to be the correct one, then the EmDrive may not be useful for any kind of propulsion, and would at best remain as an interesting test framework for various physics variants.....There are several people that think the same way (that it cries out for a space test), while there are several other ones that think it would be premature. Since you made a powerful argument for the energy paradox, it would be useful if you could list all the reasons (and what and how should be tested) why a space test should be the next step, as a powerful argument in that direction may help to push the ball rolling...upwards :)
Really and truly, this experiment cries out for a space test.
...How do you reconcile this with the NASA Tests showing an impulsive force, in the same direction as the movement, which once it reaches the knee of the uprise, after ~2 sec it either stays fairly constant or continues increasing at a much smaller rate?. None of the NASA tests showed a Dirac delta function type of response. None of the NASA tests showed the force decreasing to zero once the EM Drive started to move, on the contrary, the force stayed constant or it increased.
And so this third thrust scenario is this:
As soon as the EmDrive is free to move, a definite and constant momentum is established and its thrust falls to zero.
So far, so good. But given this third thrust scenario is the correct one, what then is expected to happen when we switch off the power?
FYI Arghhhh!
Wasted this rare free day chasing constant acceleration transforms til I remembered my own hypothesis is based on negative feedback of the acceleration. (shows what can happen once the bit is in the mouth)
Time for a hot tub...
I'm not aware of any NASA tests on a moving EmDrive. Refs?...How do you reconcile this with the NASA Tests showing an impulsive force, in the same direction as the movement, which once it reaches the knee of the uprise, after ~2 sec it either stays fairly constant or continues increasing at a much smaller rate?. None of the NASA tests showed a Dirac delta function type of response. None of the NASA tests showed the force decreasing to zero once the EM Drive started to move, on the contrary, the force stayed constant or it increased.
And so this third thrust scenario is this:
As soon as the EmDrive is free to move, a definite and constant momentum is established and its thrust falls to zero.
So far, so good. But given this third thrust scenario is the correct one, what then is expected to happen when we switch off the power?
..
I'm not aware of any NASA tests on a moving EmDrive. Refs?
As for the static force profile, the small residual increase appears to have a slope that matches, to within experimental accuracy, the prevailing thermal drift.
Briefly moving, yes, but constrained from free dynamics - which is what I'm attempting to address in all three thrust scenarios. If the torque balance shows a rectangular pulse (which it largely does, up to thermal drift), this indicates the prompt onset of a constant force. But this arrangement by no means guarantees that the appropriate momentum, per the third thrust scenario, has been established. In fact it guarantees that it has not, since as soon as the torque balances the thrust, the balance ceases to turn and the momentum is zero. And we're back to a situation tantamount to the EmDrive pushing against an immovable wall - i.e. fully static.free dynamics ?
Recall the third thrust scenario says that the thrust only falls to zero after the appropriate momentum is established.
FYI Arghhhh!
Wasted this rare free day chasing constant acceleration transforms til I remembered my own hypothesis is based on negative feedback of the acceleration. (shows what can happen once the bit is in the mouth)
Time for a hot tub...
“Einstein box” Gedanken experiment first proposed by Balazs
N. L. Balazs, “The energy-momentum tensor of the electromagnetic field inside matter,” Phys. Rev. 91, 408-411
(1953).
for the system’s center of mass to be in the same place in both experiments, it is necessary for the slab in the latter case to have shifted to the right. The difference between the free-space momentum of the pulse and its electromagnetic (or Abraham) momentum is thus transferred to the slab in the form of mechanical momentum, pM, causing the slab’s eventual displacement in a manner consistent with the demands of the Einstein box experiment.
http://bit.ly/1DZl2z6
Resolution of the Abraham-Minkowski Controversy
Masud Mansuripur
College of Optical Sciences, The University of Arizona, Tucson, Arizona 85721
[Published in Optics Communications 283, 1997-2005 (2010)]
The dielectric insert may be acting as the slab. That produces a solid movement towards the small end according to Balazs, which is what NASA observes. However, the small end of the EM Drive is not open, so doesn't the wave reflect on the small end's copper surface and therefore enters the dielectric again now heading in the direction towards the big end which produces a movement towards the big base? back and forth?
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635478;image)
Kurt,
I wish I knew the type of interface to use. I am not an expert in microwave components, but I'm researching as time permits. Also, at 2.4503 GHz, it's going to be pretty large. Did you calculate the wave velocity for that mode?
Todd
Zellerium
May I suggest using a curved mirror as it results in greater relational movement of the laser dot. You may find them in some hardware shops? or some womens makeup departments according to my daughter.
At a minimum you will need two strings, one for front, one for rear of the unit. This will minimise sideways /rotational translation which would mask effects. Keep each string separate and attach each to the roof.
If you still get sideways torque/momentum due to induced mechanical events derived from the switching on/off of the magnetron etc then you may require 4 strings, one on each "corner" of the unit.
I am happy that you found my position on the energy paradox powerful. But speaking of premature, some further mulling and reading - ongoing - tells me that there may well be a third possibility for the behaviour of the thrust over time. If this "third thrust scenario" turns out to be the correct one, then the EmDrive may not be useful for any kind of propulsion, and would at best remain as an interesting test framework for various physics variants.....There are several people that think the same way (that it cries out for a space test), while there are several other ones that think it would be premature. Since you made a powerful argument for the energy paradox, it would be useful if you could list all the reasons (and what and how should be tested) why a space test should be the next step, as a powerful argument in that direction may help to push the ball rolling...upwards :)
Really and truly, this experiment cries out for a space test.
A third thrust scenario
Again we assume that the measured thrust is actual. We note its two characteristics:
a) It is measured as a static force.
b) It remains constant as long as input power is applied to this static configuration.
'a)' implies that we can only theorise as to its dynamic behaviour - i.e. when the EmDrive moves over time.
I take together two further pieces of information:
1. Shawyer's video of the moving EmDrive
2. Mike McCulloch's MiHsC theory of operation.
Now of course, there are a variety of interpretations possible for both of these. For example, that the video is flawed because all the angular momentum is being supplied by imperfections in the air bearing. Or that Mike's theory is nonsense because it violates GR. And so forth. So here I have to decide what to assume so as to justify this 3rd scenario. So here I choose:
1. The vid shows that an impulse is produced which results in a real and constant momentum of the EmDrive.
2. The theory predicts the same thing - constant forward EmDrive momentum.
And so this third thrust scenario is this:
As soon as the EmDrive is free to move, a definite and constant momentum is established and its thrust falls to zero.
So far, so good. But given this third thrust scenario is the correct one, what then is expected to happen when we switch off the power?
Yes. It is not a propellant-less thruster anymore.
I keep looking at this and thinking it's not right.
(http://i1365.photobucket.com/albums/r745/LASJayhawk/image.jpg1_zpszvfxogt9.jpg) (http://s1365.photobucket.com/user/LASJayhawk/media/image.jpg1_zpszvfxogt9.jpg.html)
It looks to symmetrical.
COMSOL's website says the RF module can do far field calculations, and the antenna placement would appear to put at least part of the frustum in the near field. It looks by eyeball that the software is only looking at the far field being reflecting off the small end of the frustum.
Or am I missing something?
This COMSOL Finite Element Analysis solution is a numerical solution of Maxwell's differential equations, taking into account the boundary conditions, including the losses responsible for the finite Q. What you are looking at is the steady state of the electromagnetic fields.
The steady state electromagnetic field solution are standing waves. Although the initial condition is not symmetrical, due to travelling waves, this is a very-short-lived transient, as the solution soon reaches a (practically) symmetric steady state.
This has been shown by @aero with a very interesting movie based on a 2D solution of the truncated cone as a flat trapezium using MEEP which is a Finite Difference code (free from MIT alumni) that performs the full transient solution. It was neat to see how the (practically) symmetric steady state was soon reached starting from an unsymmetric initial condition.
Furthermore, as pointed out by RotoSequence, the steady state solution for the magnetic field and a COMSOL thermal analysis was corroborated by temperature measurements using an infrared thermal camera, which verifies that the heating is due to induction heating from the magnetic field.
I obtained an exact solution for the symmetric steady state (which of course does not take into account the initial unsymmetric transient) and it fully verifies NASA's COMSOL FEA steady state solution for the electromagnetic field: the natural frequency is within 1% of the exact solution and the mode shapes are extremely close (I posted the exact solution comparison some time ago).
If one is interested in near-field far-field, transient, fully complex solution (including initial travelling waves morphing into standing waves, as well as evanescent waves) then one has to resort to a time-marching solution as with MEEP finite difference approach or a [FEA in space/FD in time] solution that imposes a finite element discretization in space and a finite difference time discretization. (Such a transient, 3D solution containing evanescent waves is extremely time consuming.)
And while on the subject of simulation: Guido Fetta of Cannae tells me that his COMSOL(?unsure) sim predicts a nonzero net Lorentz force for his device. Now, we all learned that no closed system of currents can produce such a net force. There's a paradox. He insists that there are no significant cumulative rounding errors.
Anyone have insight into this?
There cannot be a paradox.
Let's remember that the COMSOL FEA solution is the steady state solution showing the spatial distribution of the field. Remember that the steady state solution of Maxwell's differential equations can be accomplished by separation of variables.
The harmonic (time varying) part of the field is assumed. So, for example, the Magnetic Field shown on the COMSOL output is the spatial distribution of the magnetic field. Now, what is shown as a maximum and what is shown as a minimum is arbitrary, since depending at what time one arbitrarily chooses to display the magnetic field, as the magnetic field varies with time like a harmonic function.
Similarly, the Poynting vector is a harmonic function of time, and this is, as you point out, well known in the literature, with a frequency which is twice the frequency of the magnetic and the electric field.
Although the spatial distribution of the Poynting vector is non-zero at arbitrary points in time, over a whole cycle the Poynting vector (and the Lorentz force) for a cavity sums up to exactly zero, just like the mean of the magnetic and electric fields is also zero. COMSOL is an excellent package.
The Poynting vector solution of Maxwell's equations points towards the Big Base half of the time, and points towards the Small Base half of the time.
COMSOL will not tell that to the analyst obtaining a steady solution where the harmonic function of time is implicit.
It is recommended that COMSOL and any other FEA packages (ANSYS MultiPhysics, etc., ABAQUS, ADINA, NASTRAN) should be run by experienced FEA analysts, to prevent errors. (Ditto for FD, control volume , and any other numerical packages).
It is my understanding, from what Paul March wrote, that the main controlling parameter in determining the thrust generation performance of the EM-Drive is the rate of phase modulation of the RF signal that is injected into the resonant cavity.
This requires an FM modulated signal of around 100 kHz deviation that dithers back and forth around the resonant cavity's resonant frequency as fast as possible.
COMSOL is an excellent package.Sure, but I wouldn't use a wrench in place of a screwdriver either. The utility of COMSOL should not be extended past where it is useful. COMSOL has no usefulness beyond the "knowns." The unknowns can't be simulated. See Paul March & Mr. Shawyer's comments in this post, in screenshots and quotes.
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
Yes. It is not a propellant-less thruster anymore.
Capacitors and batteries lose mass when they are discharged.
For the last month I've been digging through the mountains of well thought out (some not so well thought out) material, tests and ideas of why this EM Drive does what it does. It's a beautiful conundrum. For over 40 years as an engineer I've built/designed/tested computers, electronics, electro-mechanical, semiconductor machines, imaging systems for the Super Conductor Super Collider , the list is long.Following on what jknuble said about the multipactor-like effect as a possible cause of thrust. http://en.wikipedia.org/wiki/Multipactor_effect I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust.
For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.
I can think of 3 ways to debunk this. 1) perhaps that amount of particles going that fast would be noticeable with the naked eye, so this isn't really a valid explanation. 2) stick a detector behind the thruster (are they ionized?). 3) SEM of the surface compared to scraps from the same batch of copper not used in the thrustum.
Just how would we get a net-thrust from a closed cavity with atomization. Even if atoms are being ioniozed inside the cavity I don't see how that could result in a net thrust. Atomization results in immediate thrust but then that creates impact on the other side of the cavity canceling out the propulsion.
Yes. It is not a propellant-less thruster anymore.
Capacitors and batteries lose mass when they are discharged.
Capacitors can have interesting aspects
213310.pdf (http://infinitas.co/r.d.d/project/framework/docs/em-quantum/nasa213310.pdf)
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
...
There must be some way of coupling the RF power to the cavity using feed horns or near-field antennas. That would eliminate the need to weigh down the balance with a PA, batteries or achive a workable cummutator. There may not be much gain at the frequency of interest but all you want to do is to transmit a fraction of the power. Maybe 2 identical collinear dipoles would work. The recieve dipole, mounted on the outside of the cavity, would connect to the internal loop used to drive the cavity. If you have access to a network analyzer you could optimize the match and maximize the return loss.
Not a single thing I built defied the laws of physics or the formulas of the trade. . . Maxwell, Ohms law, etc. If something didn't work for some weird reason, it still followed the basic laws and formulas when it ended up.
It doesn't really matter to me what is happening inside of the EM Chamber it must follow the principals of physics and conservation of energy and momentum is one of them. If I have a Air Tank pressurized with 200psi of air and a audio speaker inside that can blast at 100 watts any frequency range no matter what mixture of sound or what mixture of harmonics I crank, the tank will not move, but put a hole in one end and stand back. The second law of thermodynamics states that the entropy of an isolated system never decreases and the EM Chamber is an isolated enclosed system, we think. If we are getting thrust that, thrust must be acting outside the chamber in some form. This is why I asked the simple question if smoke was used in the tests, it wasn't to detect thermal air currents but to see if it was moving away from any thrust from the EM Chamber. Smoke is small .5 to 2 um and might be be directly effected. If not then look for other forms of accelerated energy, providing thrust emanating out of the EM Chamber.
...EDIT: Please click on the above link to see the above quotation which is not reproduced in full in order to save bandwidth
the utility of COMSOL in figuring out this problem is limited as COMSOL is considering the standing wave and isn't considering the traveling wave. It gives no consideration to what is happening over extended time (over multiple full cycles) or to what is happening to a resonant cavity under dynamic operation, for example while under acceleration. COMSOL provides no insight as to what is happening when the resonant cavity is being excited by FM or other sources of phase noise.
the standing wave is constructed by the addition, in phase, of a continuous travelling wave. This travelling wave results in the forces that are produced on the end plates which are orthogonal to the group velocity vector of the wave. In a cavity with the correct radius spherical end plates there is no force on the side walls due to the travelling wave, because the walls are parallel to the group velocity vector
The forces produced by travelling waves in a waveguide were first investigated theoretically and experimentally by Prof. Alex Cullen back in the 1950s. His analysis is as true today as it was when he first did the work
.. There is a very neat quantum mechanical reason that such a container is not truly closed. Even in an infinite potential well, the wave function can extend outside the walls of the well, leading to effects such as tunneling. Another great example of the wavefunction extending beyond barriers that appears to be somewhat related to the possible effect seen here is the Aharanov Bohm effect: http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect (http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect). This is due to the wavefunction of a particle outside of a container extending past the barrier of the container and interacting with the EM field on the inside of the container.A warm welcome to the forum and thank you for a great post. :)
...
....
A) We should make an effort to properly characterize Finite Element solution packages like COMSOL that are able to obtain solutions to a large number of physical problems. COMSOL is not just a "wrench" but a whole tool box of solutions.
the utility of COMSOL in figuring out this problem is limited as COMSOL is considering the standing wave and isn't considering the traveling wave. It gives no consideration to what is happening over extended time (over multiple full cycles) or to what is happening to a resonant cavity under dynamic operation, for example while under acceleration. COMSOL provides no insight as to what is happening when the resonant cavity is being excited by FM or other sources of phase noise. Building off the comments about COMSOL's ability to simulate mode shapes
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
Not a single thing I built defied the laws of physics or the formulas of the trade. . . Maxwell, Ohms law, etc. If something didn't work for some weird reason, it still followed the basic laws and formulas when it ended up.
It doesn't really matter to me what is happening inside of the EM Chamber it must follow the principals of physics and conservation of energy and momentum is one of them. If I have a Air Tank pressurized with 200psi of air and a audio speaker inside that can blast at 100 watts any frequency range no matter what mixture of sound or what mixture of harmonics I crank, the tank will not move, but put a hole in one end and stand back. The second law of thermodynamics states that the entropy of an isolated system never decreases and the EM Chamber is an isolated enclosed system, we think. If we are getting thrust that, thrust must be acting outside the chamber in some form. This is why I asked the simple question if smoke was used in the tests, it wasn't to detect thermal air currents but to see if it was moving away from any thrust from the EM Chamber. Smoke is small .5 to 2 um and might be be directly effected. If not then look for other forms of accelerated energy, providing thrust emanating out of the EM Chamber.
I too would like to see a smoke test. I can't see conservation of momentum being violated. It just goes against everything we know both empirically and theoretically. I think that even in the off chance that the EmDrive is not experimental error, conservation of momentum will still hold albeit in a more subtle manner than the classical analysis would expect.
You gave the illustrative example of a closed container with different traveling and standing waves of different frequencies and amplitudes bouncing around inside. There is a very neat quantum mechanical reason that such a container is not truly closed. Even in an infinite potential well, the wave function can extend outside the walls of the well, leading to effects such as tunneling. Another great example of the wavefunction extending beyond barriers that appears to be somewhat related to the possible effect seen here is the Aharanov Bohm effect: http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect (http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect). This is due to the wavefunction of a particle outside of a container extending past the barrier of the container and interacting with the EM field on the inside of the container.
Now I leave this paper to ruminate upon:
http://arxiv.org/abs/0708.0681 (http://arxiv.org/abs/0708.0681)
Perhaps the EmDrive is acting as an evanescent mode photon rocket where momentum is carried away outside the cavity via this mechanism.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608
I believe the series of successful vacuum tests negates the need for a smoke stick test. Comments?
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
Great news, hopefully all those replication attempts by individuals or small teams will shed light on relevant parameters, and you are on the forefront. Can't you you go battery without DC/DC, what are the DC requirement of your RF amplifier ?
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
Just a wild idea, but have you considered this form of powering :
http://en.wikipedia.org/wiki/Wireless_power
basically, contact-less induction would give you frictionless movement (except for the bearing friction and air resistance) and provide power. I'm however not sure what the electromagnetic implications would be on any surrounding devices...(fe, does it act as a magnetic brake?)
Secondly, not sure what would be needed to feed 1Kw of power. It might be not so practical all together...
Although.... I've seen street based induction plates for loading batteries of electric cars.
well.. it's just a wild idea flare... :)
:) In the 80s I remember being poo-pooed by a physics professor when I told him the the junction speeds in an IC or even transistor was the same as sound. Acoustic speed in the IC substrate. It's true, do the numbers for amorphous silicon or GAS. I like to keep an open mind and if something new presents itself in the violation of some of our ideas of how things work, I will jump on the bandwagon.
I can remember experiments (if not the references) of time delay measurements of sub-cutoff frequency waveguide transmission. They were loudly poo-pooed at the time as claiming FTL information.
Update on the replication attempt.
I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.
If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs.
https://goo.gl/Q3jGN1
Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf
There must be some way of coupling the RF power to the cavity using feed horns or near-field antennas. That would eliminate the need to weigh down the balance with a PA, batteries or achive a workable cummutator. There may not be much gain at the frequency of interest but all you want to do is to transmit a fraction of the power. Maybe 2 identical collinear dipoles would work. The recieve dipole, mounted on the outside of the cavity, would connect to the internal loop used to drive the cavity. If you have access to a network analyzer you could optimize the match and maximize the return loss.
I need 6VDC 2A and 5VDC 2A. I guess this is a good time to explain my reasoning here. I am a firm believer that this EMdrive technology (if it is even viable) will never get off the ground if it isn't introduced and validated in a very public way.
One of my original goals was to encourage replication attempts by not only academia (which has resources) but also to make it accessible to your average Joe. In keeping with the second goal, I have decided to go with Plain Jane COTS wifi gear and see if I can make something work with that.
I'm well aware of how stupid that sounds.
I know that the frustum design that I currently have was originally driven by a high power (and dangerous to most people) magnetron. The frequency range of your average microwave oven magnetron and wifi are the same. I verified the frustum will resonate within this frequency range using a spectrum analyzer and a SNA. Mine works on wifi channel 1 and 10. Given that Eagleworks was able to observe thrust with only 2.6 watts for one of their tests*, I think this is an acceptable risk to take. Besides, it is just money right? So I am literally driving the frustum with the RF from the wifi camera (used to observe and is riding on the experiment) and a 2watt amp. I can scale this up to 20 watts using other amps if needed. Amps are cheap and plug and play.
* http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think the frequency hopping aspect of the waveform might end up doing me in though.
So this is a gamble. I'm accepting the risk of not getting a successful replication attempt in hopes that if I do, I will have built a ready-made solution for mister tinkerer to easily observe anomalous thrust at home.
If all that fails, I'll just shove in a magnetron. I deal with voltages at work (big fry your eyeballs out radars) that literally will and do make your hair stand up on end as soon as you open the cabinet, so I'm comfortable with them too.
:) In the 80s I remember being poo-pooed by a physics professor when I told him the the junction speeds in an IC or even transistor was the same as sound. Acoustic speed in the IC substrate. It's true, do the numbers for amorphous silicon or GAS. I like to keep an open mind and if something new presents itself in the violation of some of our ideas of how things work, I will jump on the bandwagon.
I can remember experiments (if not the references) of time delay measurements of sub-cutoff frequency waveguide transmission. They were loudly poo-pooed at the time as claiming FTL information.
As I've mentioned, I am a strong proponent of a completely stand-alone system when it comes to measuring purported thrust from exotic devices (propellantless thrusters). The simple act of coupling to the stationary lab frame be it via coax, RF, Galinstan contacts or whichever, brings with it the possibility of artifacts masquerading as measured thrust. The whole thing has to be in a sealed box. And even then we are not out of the woods. Thermal power will tend to "balloon" the box volume and generate a buoyancy signal if the box is in air, aligned with local gravity's direction. Charges may accumulate on the box and generate phantom forces. Magnetic fields from outside, and/or from inside, may penetrate the box and also generate phantom forces. Only in space can all these phantoms be banished.
In space we need no balance; nor do we need any kind of force sensor. All we need is a measurement system to log the position of the DUT relative to its original null geodesic. This immediately kills two birds with one stone. We get a readout of initial "static" thrust from computing the initial acceleration, and, assuming actual off-geodesic motion subsequently ensues, we get the much sought-after free space dynamics.
Position measurement implies an interaction. Were LIDAR to be used, we have to correct our measured positions by taking into account the "photon sail" effect. It will be small, but it may yet be of a comparable magnitude to the actual thrust we detect. Then there's solar wind because we're not going outside the heliosphere (yet). And there is a direct photon flux from the sun. All these need to be addressed as sources of error.
The smoke test is still a good idea. If the thrust proved to be due to experimental artifact, it could be due to multiple artifacts working in conjunction. Wasn't the thrust quite a bit smaller in the vacuum tests?
Wasn't the thrust quite a bit smaller in the vacuum tests?It sure was, you can't deny that:
I would like advice on lifetime estimates of the power within the cavity - what is the expected half life? Does a simple expression exist involving the Q-factor? I remind that Q can be defined as the angular frequency multiplied by the ratio of (stored energy) / (rate of energy dissipation).A simplistic analysis produces an expression for half-life that is independent of the stored energy, viz:
Continuing with the "Test In Space" theme.
We lack cheap space access for unmanned cargo. We have no railgun running from the coast of Ecuador up into the Andes to the east, and we have no Skylon/SABRE SSTO yet. So we must pay many thousands of dollars per launched kilogram rather than what could be only tens of dollars.
What we do have is Cubesat and SpaceX. The problem is that the devices under consideration here won't fit even into the largest Cubesat. So let's talk miniaturisation.
What we have is photons in an asymmetric cavity. So let's use light instead of microwaves. I'll stop there for now.
Continuing with the "Test In Space" theme.
We lack cheap space access for unmanned cargo. We have no railgun running from the coast of Ecuador up into the Andes to the east, and we have no Skylon/SABRE SSTO yet. So we must pay many thousands of dollars per launched kilogram rather than what could be only tens of dollars.
What we do have is Cubesat and SpaceX. The problem is that the devices under consideration here won't fit even into the largest Cubesat. So let's talk miniaturisation.
What we have is photons in an asymmetric cavity. So let's use light instead of microwaves. I'll stop there for now.
I like where you're going with this...........and I want to talk miniaturization too. @Notsosureofit is working with 10ghz gunn diodes so he might be able to help.
Judging from reading (and really reading) the latest tweets from @ElonMusk, I feel that one of these Emdrive tests will find a ride on a rocket real soon. :)
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1368379#msg1368379
Note there is also a (very much new) favorable Io9 article released on April 30th,
(A day after this: http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/)
that wasn't linked to in the tweet. What was linked to was an old negative article from August last year.
I know that the frustum design that I currently have was originally driven by a high power (and dangerous to most people) magnetron. The frequency range of your average microwave oven magnetron and wifi are the same. I verified the frustum will resonate within this frequency range using a spectrum analyzer and a SNA. Mine works on wifi channel 1 and 10. Given that Eagleworks was able to observe thrust with only 2.6 watts for one of their tests*, I think this is an acceptable risk to take. Besides, it is just money right? So I am literally driving the frustum with the RF from the wifi camera (used to observe and is riding on the experiment) and a 2watt amp. I can scale this up to 20 watts using other amps if needed. Amps are cheap and plug and play.
* http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
I think the frequency hopping aspect of the waveform might end up doing me in though.
So this is a gamble. I'm accepting the risk of not getting a successful replication attempt in hopes that if I do, I will have built a ready-made solution for mister tinkerer to easily observe anomalous thrust at home.
If all that fails, I'll just shove in a magnetron.
Not a single thing I built defied the laws of physics or the formulas of the trade. . . Maxwell, Ohms law, etc. If something didn't work for some weird reason, it still followed the basic laws and formulas when it ended up.
It doesn't really matter to me what is happening inside of the EM Chamber it must follow the principals of physics and conservation of energy and momentum is one of them. If I have a Air Tank pressurized with 200psi of air and a audio speaker inside that can blast at 100 watts any frequency range no matter what mixture of sound or what mixture of harmonics I crank, the tank will not move, but put a hole in one end and stand back. The second law of thermodynamics states that the entropy of an isolated system never decreases and the EM Chamber is an isolated enclosed system, we think. If we are getting thrust that, thrust must be acting outside the chamber in some form. This is why I asked the simple question if smoke was used in the tests, it wasn't to detect thermal air currents but to see if it was moving away from any thrust from the EM Chamber. Smoke is small .5 to 2 um and might be be directly effected. If not then look for other forms of accelerated energy, providing thrust emanating out of the EM Chamber.
I too would like to see a smoke test. I can't see conservation of momentum being violated. It just goes against everything we know both empirically and theoretically. I think that even in the off chance that the EmDrive is not experimental error, conservation of momentum will still hold albeit in a more subtle manner than the classical analysis would expect.
You gave the illustrative example of a closed container with different traveling and standing waves of different frequencies and amplitudes bouncing around inside. There is a very neat quantum mechanical reason that such a container is not truly closed. Even in an infinite potential well, the wave function can extend outside the walls of the well, leading to effects such as tunneling. Another great example of the wavefunction extending beyond barriers that appears to be somewhat related to the possible effect seen here is the Aharanov Bohm effect: http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect (http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect). This is due to the wavefunction of a particle outside of a container extending past the barrier of the container and interacting with the EM field on the inside of the container.
Now I leave this paper to ruminate upon:
http://arxiv.org/abs/0708.0681 (http://arxiv.org/abs/0708.0681)
Perhaps the EmDrive is acting as an evanescent mode photon rocket where momentum is carried away outside the cavity via this mechanism.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The equations of motion do not exist from an inertial reference frame. We must assume that the object is not moving and that space is moving around and through the object. I am trying to develop the Hamiltonian for space but having difficulty because we have always assumed space to be a virtual plasma and it is not virtual at all, but real.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The equations of motion do not exist from an inertial reference frame. We must assume that the object is not moving and that space is moving around and through the object. I am trying to develop the Hamiltonian for space but having difficulty because we have always assumed space to be a virtual plasma and it is not virtual at all, but real.
Bumping this because of its elegance.
I'm asking about the energy in the cavity (for reasons that may be clearer later). Here's a really dumb way to calculate it. This is so ugly, I hope someone shoots it down. It goes like this:Resonate circuit has a time constant. 5 time constants to fill.
We know the input power, so it remains only to estimate the time to "fill" the cavity. We can think of the Q factor as the number of bounces inside the cavity (!). Taking Q=6,000 and L = 0.25 m, we get t = 5 us.
Thus for an input power of 50 W, the cavity energy is 2.5*10-4 Joules.
Pretty bad hunh?
Another way to calculate it is to take the cavity volume and the average E-field from the simulation, and then the cavity energy is 0.5*epsilon0*E2*V Joules.
t(fill) = 5*Q/w then. With (Q=6000, f = 2.4 GHz) , t(fill) = 2 us.I'm asking about the energy in the cavity (for reasons that may be clearer later). Here's a really dumb way to calculate it. This is so ugly, I hope someone shoots it down. It goes like this:Resonate circuit has a time constant. 5 time constants to fill.
We know the input power, so it remains only to estimate the time to "fill" the cavity. We can think of the Q factor as the number of bounces inside the cavity (!). Taking Q=6,000 and L = 0.25 m, we get t = 5 us.
Thus for an input power of 50 W, the cavity energy is 2.5*10-4 Joules.
Pretty bad hunh?
Another way to calculate it is to take the cavity volume and the average E-field from the simulation, and then the cavity energy is 0.5*epsilon0*E2*V Joules.
TC = Q / (2 Pi Fr).
Shawyer did comment on this and gave example.
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The equations of motion do not exist from an inertial reference frame. We must assume that the object is not moving and that space is moving around and through the object. I am trying to develop the Hamiltonian for space but having difficulty because we have always assumed space to be a virtual plasma and it is not virtual at all, but real.
Bumping this because of its elegance.
Continuing with the "Test In Space" theme.
We lack cheap space access for unmanned cargo. We have no railgun running from the coast of Ecuador up into the Andes to the east, and we have no Skylon/SABRE SSTO yet. So we must pay many thousands of dollars per launched kilogram rather than what could be only tens of dollars.
What we do have is Cubesat and SpaceX. The problem is that the devices under consideration here won't fit even into the largest Cubesat. So let's talk miniaturisation.
What we have is photons in an asymmetric cavity. So let's use light instead of microwaves. I'll stop there for now.
Sure, but I'm just pointing out what the lack of cheap and readily available space access costs us in terms of either proving or disproving new propulsion theories. It would have saved Woodward 20 years of mucking about, for instance. It will cost this endeavour years also.And I proposed a petition to Elon Musk / SpaceX. Nobody replied, is it such a bad idea?
Various explanations, both of spacecraft behavior and of gravitation itself, were proposed to explain the anomaly. Over the period 1998–2012, one particular explanation became accepted. The spacecraft, which are surrounded by an ultra-high vacuum and are each powered by a radioisotope thermoelectric generator (RTG), can shed heat only via thermal radiation. If, due to the design of the spacecraft, more heat is emitted in a particular direction—what is known as a radiative anisotropy—then the spacecraft would exhibit a small acceleration in the direction opposite that of the excess emitted radiation due to radiation pressure. Because this force is due to the recoil of thermal photons, it is also called the thermal recoil force. If the excess radiation and attendant radiation pressure were pointed in a general direction opposite the Sun, the spacecrafts’ velocity away from the Sun would be decelerating at a greater rate than could be explained by previously recognized forces, such as gravity and trace friction, due to the interplanetary medium (imperfect vacuum).
By 2012 several papers by different groups, all reanalyzing the thermal radiation pressure forces inherent in the spacecraft, showed that a careful accounting of this could explain the entire anomaly, and thus the cause was mundane and did not point to any new phenomena or need for a different physical paradigm.[2][3] The most detailed analysis to date, by some of the original investigators, explicitly looks at two methods of estimating thermal forces, then states "We find no statistically significant difference between the two estimates and conclude that once the thermal recoil force is properly accounted for, no anomalous acceleration remains
{snip}An interstellar probe would have to be powered by a nuclear reactor. Currently the cooling radiators for nuclear reactors are flat but curving metal, to produce the equivalent of a nozzle, is not hard.
Wild speculation 2:
If this is some sort of thermal drive, then perhaps...thrust remains constant only for so long as the temperature increases? So, if the temperature plateau's, then thrust declines. This might provide a solution of sorts to the Conservation of Energy issue.
If this is the case, then the EM drive might make for a useful orbital thruster, and perhaps power interplanetary probes...but would it be adequate for interstellar propulsion?
Something I have thought about before and am thinking about once again is thermal effects. Virtually every engineer or theorist to jump into these EM Drive threads has cited thermal artefacts as a possible solution for EM Drive thrust. Doctor Rodal's first posts in the original thread dealt with this. Back then, the reasoning was:
1) thermal effects could mimic significant thrust in ambient air conditions;
2) those same thermal effects would still produce thrust, albeit far smaller thrust, in a vacuum on earth;
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
I was discussing this last night and we made some interesting observations. In a variable dielectric, like in the frustum, when the waves are accelerating to a higher group velocity, they are losing momentum. This momentum is lost to the material "in the direction of the wave". It is similar to frame dragging. The wave is losing energy trying to drag the waveguide or the dielectric with it.
After the wave is reflected, it again tries to drag the dielectric or frustum with it, and this time it meets more resistance. It becomes an evanescent wave and decays faster.
I do not believe a small end cap is needed and the frustum should taper all the way down to the wave guide feeding it. The reflected waves cannot reach the small plate. That's what the thermal images show as well. Most of the energy I think should be trapped at the big end.
Todd D.
@zellerium:NASA's Eagleworks base is made of glass-fiber reinforced epoxy with an extremely thin layer (deposited) of copper
70oC temperature difference across the copper? But it's an excellent conductor of heat. I can't imagine that.
Continuing with the "Test In Space" theme.
We lack cheap space access for unmanned cargo. We have no railgun running from the coast of Ecuador up into the Andes to the east, and we have no Skylon/SABRE SSTO yet. So we must pay many thousands of dollars per launched kilogram rather than what could be only tens of dollars.
What we do have is Cubesat and SpaceX. The problem is that the devices under consideration here won't fit even into the largest Cubesat. So let's talk miniaturisation.
What we have is photons in an asymmetric cavity. So let's use light instead of microwaves. I'll stop there for now.
I know Shawyer and EW have tried a dielectric in the frustum. Are there any specifications for that dielectric? Material properties? Absorption properties at microwave frequencies?
I was looking at Pyramid Absorbers for microwaves, they can attenuate up to -55dB. A high power microwave source, pumped through a diode into such an absorber, seems to me should have a higher probability of thrust than the EM Drive and relatively simple to construct.
Todd D.
A rough calc says that the Cu thickness has to be less than 44 microns. Looks like it's possible. But I calculated heat flow around the copper, not through-plane. Someone should recheck both.@zellerium:The base is made of glass-fiber reinforced epoxy with an extremely thin layer (deposited) of copper
70oC temperature difference across the copper? But it's an excellent conductor of heat. I can't imagine that.
on the outside: 0.063 inch thick FR4 printed circuit board and ~35 microns thick of Cu on the inside
Thermal conductivity, through-plane 0.29 W/(m·K)
A rough calc says that the Cu thickness has to be less than 44 microns. Looks like it's possible. But I calculated heat flow around the copper, not through-plane. Someone should recheck both.@zellerium:The base is made of glass-fiber reinforced epoxy with an extremely thin layer (deposited) of copper
70oC temperature difference across the copper? But it's an excellent conductor of heat. I can't imagine that.
on the outside: 0.063 inch thick FR4 printed circuit board and ~35 microns thick of Cu on the inside
Thermal conductivity, through-plane 0.29 W/(m·K)
P = 50 W, dT = 70oK
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
I was discussing this last night and we made some interesting observations. In a variable dielectric, like in the frustum, when the waves are accelerating to a higher group velocity, they are losing momentum. This momentum is lost to the material "in the direction of the wave". It is similar to frame dragging. The wave is losing energy trying to drag the waveguide or the dielectric with it.
After the wave is reflected, it again tries to drag the dielectric or frustum with it, and this time it meets more resistance. It becomes an evanescent wave and decays faster.
I do not believe a small end cap is needed and the frustum should taper all the way down to the wave guide feeding it. The reflected waves cannot reach the small plate. That's what the thermal images show as well. Most of the energy I think should be trapped at the big end.
Todd D.
Looking for a mechanical analogy :
Let's play with a bended pipe and a ball rolling in it. The pipe can constrain the ball to various path, it can rise or fall, at various steepness. Height of the pipe at a given location defines gravitational potential energy of the ball there. The ball is launched with a given velocity, and then turns around the pipe if it is a closed circuit, or goes back and forth if the two ends of the pipe are high enough, should make no difference.
Assuming no friction, the ball goes-on forever. When rising the ball loses kinetic energy, slows, and imparts momentum to the pipe. When on the return path (different part of pipe if circuit path or same part of pipe if going back and forth), the same delta height will make ball regain same kinetic energy as lost when rising, accelerate, and imparts momentum again. When taking curves, ball also imparts momentum on pipe. Integrating all those momentum exchanges on a cycle yields 0 net momentum. Not depending on path details.
Assuming a closed circuit path and friction (dry, viscous, magnetic... whatever dissipative interaction), including parts with low friction (forth) and parts with high friction (back) and arbitrary height profile (potential well whatever). After a number of cycles the ball will come to rest. Integrating all the momentum exchanges of ball on pipe (changes of height, curves, friction) will yield a total momentum equal to the initial momentum of the ball when launched. Not depending on path details and what parts are more or less dissipative.
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
Friction is a non-conservative force of course. The energy that is not conserved turns into heat....
Looking for a mechanical analogy :
Let's play with a bended pipe and a ball rolling in it. The pipe can constrain the ball to various path, it can rise or fall, at various steepness. Height of the pipe at a given location defines gravitational potential energy of the ball there. The ball is launched with a given velocity, and then turns around the pipe if it is a closed circuit, or goes back and forth if the two ends of the pipe are high enough, should make no difference.
Assuming no friction, the ball goes-on forever. When rising the ball loses kinetic energy, slows, and imparts momentum to the pipe. When on the return path (different part of pipe if circuit path or same part of pipe if going back and forth), the same delta height will make ball regain same kinetic energy as lost when rising, accelerate, and imparts momentum again. When taking curves, ball also imparts momentum on pipe. Integrating all those momentum exchanges on a cycle yields 0 net momentum. Not depending on path details.
Assuming a closed circuit path and friction (dry, viscous, magnetic... whatever dissipative interaction), including parts with low friction (forth) and parts with high friction (back) and arbitrary height profile (potential well whatever). After a number of cycles the ball will come to rest. Integrating all the momentum exchanges of ball on pipe (changes of height, curves, friction) will yield a total momentum equal to the initial momentum of the ball when launched. Not depending on path details and what parts are more or less dissipative.
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
The ball (photon) doesn't fall back down the well. There is nothing to give it back enough energy to do so. It dissipates in multiple reflections between the walls and the big end. They are not getting more out than they put in, so it does not violate conservation of energy. They are simply getting more NET momentum on one direction than in the other direction because there is more dissipation and attenuation in one direction than there is in the other. Dissipative systems are typically "not" conservative, loses prevent a true equal measure from occuring in both directions.
Todd D.
Do higher em frequencies deliver increased net effect?Excellent question. To which as yet we have no answers. This might be taken to imply that we should find out :)
...
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
The ball (photon) doesn't fall back down the well. There is nothing to give it back enough energy to do so. It dissipates in multiple reflections between the walls and the big end. They are not getting more out than they put in, so it does not violate conservation of energy. They are simply getting more NET momentum on one direction than in the other direction because there is more dissipation and attenuation in one direction than there is in the other. Dissipative systems are typically "not" conservative, loses prevent a true equal measure from occuring in both directions.
Todd D.
We have three tentative answers. They are the mathematical formulas based on their respective theoretical models:Do higher em frequencies deliver increased net effect?Excellent question. To which as yet we have no answers. This might be taken to imply that we should find out :)
But but but...there is no guarantee that these forces in any way combine to produce a larger force. And that's static I mean. I'm even more doubtful about the free space dynamics.
Statically we care about k, or N/W
Dynamically we don't know what we care about yet 8)
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
Our understanding of conservation is very deep, and Emmie Noether discovered it. She found that for every symmetry or invariance there exists a corresponding conservation law. For momentum it's the symmetry of space. For energy it's the symmetry of time. It's actually more mathematically complex than that, since it involves differentials of the Lagrangian.
http://en.wikipedia.org/wiki/Noether%27s_theorem
Susskind has some public lectures about all the gory details, on YouTube.
Nice rundown of most everything that can change the energy state of the Em Chamber at rest. I believe (unless new physics is discovered here, then the whole ballgame changes) whatever is happening it's going to be interesting. This rundown was the site that got me thinking.QuoteSeeShells:
The second law of thermodynamics states that the entropy of an isolated system never decreases and the EM Chamber is an isolated enclosed system, we think. If we are getting thrust that, thrust must be acting outside the chamber in some form. This is why I asked the simple question if smoke was used in the tests, it wasn't to detect thermal air currents but to see if it was moving away from any thrust from the EM Chamber. Smoke is small .5 to 2 um and might be be directly effected. If not then look for other forms of accelerated energy, providing thrust emanating out of the EM Chamber.
I agree with your thought train.
I have a feeling that we are so busy looking at the big paw print in the dirt that we don't see the bear sneaking up behind us.
Is it really the reflection/refraction of microwave photons that are the core issue here?.
Or is it the expanded energy shell they carry... that any high voltage source might carry?
It is obvious that the thermal state of the test device will be impacted.
Is the gravitational mass of the test unit "altered" between power up/power down?.
Is the "inertia" of the test device impacted?.
Is the Virtual mass of the test unit altering?, the reactionary energy based mass attachment to space-time. {Mach principle}
Does the chamber emit external acoustic waves? ( well beyond the human hearing range)
That's a nice enumeration. But what of Sonny White's PV derivative theory - called QVF I believe?@arc:We have three tentative answers. They are the mathematical formulas based on their respective theoretical models:QuoteDo higher em frequencies deliver increased net effect?Excellent question. To which as yet we have no answers. This might be taken to imply that we should find out :)
But but but...there is no guarantee that these forces in any way combine to produce a larger force. And that's static I mean. I'm even more doubtful about the free space dynamics.
Statically we care about k, or N/W
Dynamically we don't know what we care about yet 8)Quote from: John von NeumannThe sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
If a theory does not have a mathematical formula predicting variables, it doesn't qualify as a physical theory.
The predictive formulas of Shawyer and of McCulloch both are inversely proportional to the frequency. So, on the contrary, both Shawyer and McCulloch predict that the higher the frequency the smaller the thrust force.
The formulas of Shawyer and of McCulloch have no dependence on mode shape.
@Notsosureofit's formula is the only formula that shows dependence on mode shape (through the Bessel zeros, Xmn or X'mn) and hence it has a more nuanced, subtle dependence on frequency.
As the Bessel zeros Xmn (for TM modes) and X'mn (for TE modes) increase with frequency, @Notsosureofit's thrust force increases with frequency for mode shapes with (both) high m and n (circular and radial) quantum numbers (because Xmn and X'mn increase with frequency at a faster rate than the frequency itself)
@Notsosureofit's thrust force decreases with frequency for mode shapes having (both) low m and n (circular and radial) quantum numbers (but in this case some of these low m and n mode shapes may be cut off at higher frequencies).
I have a real problem believing that an oddly-shaped cavity is going to change the workings of spacetime such that translational invariance is affected. But it's a creative suggestion nonetheless. On the other hand, if the thrust is truly not a measurement artifact, I have no explanation for it.Our understanding of conservation is very deep, and Emmie Noether discovered it. She found that for every symmetry or invariance there exists a corresponding conservation law. For momentum it's the symmetry of space. For energy it's the symmetry of time. It's actually more mathematically complex than that, since it involves differentials of the Lagrangian.
http://en.wikipedia.org/wiki/Noether%27s_theorem
Susskind has some public lectures about all the gory details, on YouTube.
That's the point I want to make. We're working with a model that has proven to be correct so far, for a century. Everybody is so used to applying this powerful insight, that perception and thought patterns are fixated on it. What, for instance, if the symmetry of space is (temporarily) being changed by a device like an EM-drive? I think that such a thing might be at least in some way outside of Noether's theorem. It might all depend on whether or not the QV is immutable and indestructible. What do you think?
BR,
-CW
...I have never seen an explicit mathematical expression for Dr. White's QVF thrust force in any of his papers.
That's a nice enumeration. But what of Sonny White's PV derivative theory - called QVF I believe?
In this setup, would we be able to use one light source that's split up between all of the parallel units, or would we have individual light sources for each stack? If I understand correctly, the force observed is far more than even a perfect photon thruster, so perhaps the potential to lose energy or get conflicting thrust while redirecting photos from one source into each individual frustum might not be significant compared to the minituarization it could allow compared to having multiple sources.
Interesting concept, I like it.
10 stacks of "cavities" 100 units high arranged either side by side (flat/wall) or in a circular/tubular form. The tube would allow you to feed the energy up the middle to each drive unit.. 1000 micro-thrusters in Series-Parallel
Sounds like a 3D printing job. Glass would not stand that heat for very long... perhaps Silver?. Or Titanium with polished silver coating
Each cavity could use the wall of its neighbor for mechanical rigidity and the gaps resulting from conic shaped chambers would allow a coolant to be pumped around the cavities. Drive the units in cyclic pumped mode to minimise thermal overloading.
Our understanding of conservation is very deep, and Emmie Noether discovered it. She found that for every symmetry or invariance there exists a corresponding conservation law. For momentum it's the symmetry of space. For energy it's the symmetry of time. It's actually more mathematically complex than that, since it involves differentials of the Lagrangian.
http://en.wikipedia.org/wiki/Noether%27s_theorem
Susskind has some public lectures about all the gory details, on YouTube.
That's the point I want to make. We're working with a model that has proven to be correct so far, for a century. Everybody is so used to applying this powerful insight, that perception and thought patterns are fixated on it. What, for instance, if the symmetry of space is (temporarily) being changed by a device like an EM-drive? I think that such a thing might be at least in some way outside of Noether's theorem. It might all depend on whether or not the QV is immutable and indestructible. What do you think?
BR,
-CW
We have three tentative answers. They are the mathematical formulas based on their respective theoretical models:Do higher em frequencies deliver increased net effect?Excellent question. To which as yet we have no answers. This might be taken to imply that we should find out :)
But but but...there is no guarantee that these forces in any way combine to produce a larger force. And that's static I mean. I'm even more doubtful about the free space dynamics.
Statically we care about k, or N/W
Dynamically we don't know what we care about yet 8)Quote from: John von NeumannThe sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
If a theory does not have a mathematical formula predicting variables, it doesn't qualify as a physical theory.
The predictive formulas of Shawyer and of McCulloch both are inversely proportional to the frequency. So, on the contrary, both Shawyer and McCulloch predict that the higher the frequency the smaller the thrust force.
The formulas of Shawyer and of McCulloch have no dependence on mode shape.
@Notsosureofit's formula is the only formula that shows dependence on mode shape (through the Bessel zeros, Xmn or X'mn) and hence it has a more nuanced, subtle dependence on frequency.
As the Bessel zeros Xmn (for TM modes) and X'mn (for TE modes) increase with frequency, @Notsosureofit's thrust force increases with frequency for mode shapes with (both) high m and n (circular and radial) quantum numbers (because Xmn and X'mn increase with frequency at a faster rate than the frequency itself)
@Notsosureofit's thrust force decreases with frequency for mode shapes having (both) low m and n (circular and radial) quantum numbers (but in this case some of these low m and n mode shapes may be cut off at higher frequencies).
Testing experiments have not yet been performed at a large enough range of frequencies to discriminate whether any of these formulas is correct with respect to frequency variation.
In this context, performing experiments at higher microwave frequencies, perhaps using a Gunn Diode would be most helpful.
...My recollection (from running numerical examples at the time at which you were planning to run experiments with a Gunn diode) is that at large Xmn, with both m~n simultaneously highest, Xmn increases higher than f, so that
Really hadn't thought about it, but at large X, isn't f prop X ? and NT prop X^2/f^3 ??
It occurs to me to ask a history question about all this. What on Earth occasioned Shawyer in the first place to carefully measure thrust on this odd-shaped cavity?Did read Shawyer, back in his sat days, noticed unexpected sat movements when certain on board microwave systems were powered on which could not be explained via conventional expectations.
The team claims to have undergone seven independent reviews from experts at BAE Systems, EADS Astrium, Siemens and the IEE. The DTI has awarded the company £125,000 to develop a prototype engine as part of a three-year, £250,000 programme.
Read more: http://www.theengineer.co.uk/news/defying-gravity/266633.article#ixzz3Zq1ARpVP
It occurs to me to ask a history question about all this. What on Earth occasioned Shawyer in the first place to carefully measure thrust on this odd-shaped cavity?Isn't the answer given by the statements Shawyer makes in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829636 ? , particularly his claim that
In a cavity with the correct radius spherical end plates there is no force on the side walls due to the travelling wave, because the walls are parallel to the group velocity vector
...My recollection (from running numerical examples at the time at which you were planning to run experiments with a Gunn diode) is that at large Xmn, with both m~n simultaneously highest, Xmn increases higher than f, so that
Really hadn't thought about it, but at large X, isn't f prop X ? and NT prop X^2/f^3 ??
Xmn (f) ~ f ^y where y>1
Need y>3/2 in order for thrust force to increase with frequency.
My recollection is that the thrust force predictions using your formula for the Gunn Diode frequency were much higher than the predictions of Shawyer and McCulloch.
EDIT: Also the calculations for Shawyer's Flight Thruster (which I recall was run at higher frequency: 3.85GHz, twice the frequency of NASA's EM Drive tests)
Is my memory correct ? (too bad that we don't have a good search function to look for things like that :( )
It occurs to me to ask a history question about all this. What on Earth occasioned Shawyer in the first place to carefully measure thrust on this odd-shaped cavity?Isn't the answer given by the statements Shawyer makes in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829636 ? , particularly his claim thatQuote from: ShawyerIn a cavity with the correct radius spherical end plates there is no force on the side walls due to the travelling wave, because the walls are parallel to the group velocity vector
This claim that there are no forces on the side walls is contradicted by a calculation of Maxwell's stress tensor, particularly under classical electromagnetism, as explicitly shown by Greg Egan (http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html ) for example for such a truncated cone with spherical ends. Shawyer (to my knowledge) has never adequately answered Greg Egans's proof.
However, if one believes (as Shawyer does) that there are no forces on the conical side walls, then Shawyer's construction immediately follows.
NOTE: To my knowledge, no closed cavity truncated cones (as in Shawyer's EM Drive) are used for microwave communication satellites.
...QuoteThe team claims to have undergone seven independent reviews from experts at BAE Systems, EADS Astrium, Siemens and the IEE. The DTI has awarded the company £125,000 to develop a prototype engine as part of a three-year, £250,000 programme.
Read more: http://www.theengineer.co.uk/news/defying-gravity/266633.article#ixzz3Zq1ARpVP
At the wider end of the cone the wave travels at the speed of light, while at the other the wave travels at one tenth of that speed, due to the geometry of the waveguide.
This creates higher radiation pressure at the wider end of the waveguide because the rate of change of momentum of the waves is different. Newton’s second law defines force as the rate of change of momentum.
Shawyer explained that if these forces were the result of a working fluid, there would merely be a mechanical strain in the waveguide walls. But as the working fluid is replaced by an electromagnetic wave at close to the speed of light, Newtonian mechanics are replaced with the special theory of relativity.
’The electromagnetic wave is going at very high velocities, so you have to apply two different reference planes,’ he said. ’It can no longer be considered a closed system. As soon as you approach the speed of light the wave can be considered completely independent of the waveguide.’ Shawyer compared the engine to a laser gyroscope, which also relies on Einstein’s laws, where attitude information is obtained from an apparently closed system.
The reason for the confusion over the violation of classical physics is because this system has nothing to do with classical physics. Moreover, the “thrust” that is being calculated is not thrust at all but space moving the drive from one position to another which can merely be related to thrust but is not, per se, thrust. The controlling factor here is, of course, the resonant frequency. If you match the resonant frequency that space uses to “hold” the object you will develop a “cavity” that the “object will move towards”. The reason why the device cannot be “pushed off of” for conservation of momentum to hold true is because space is already pushing on it satisfying the law.Interesting! Would you then be prepared to write down the equations of motion so that we can play with them?
A couple of postulates to keep in mind that will help with these experiments are:
1. Space creates light.
2. Space itself is a resonating chamber.
The Mexican hat potential is a good place to start, I think, but not sure yet. It seems reasonable because it might coalesce with symmetry breaking.
You and Mulletron seem to be going in the same direction, you might want to bounce ideas off each other...
I'm wondering, in the context of dr. rodal's remark on Shawyer's theory, where he (Shawyer) poses that forces are to be observed on the ends only, what would happen if one or both ends were to be replace by Cullen type ring reflector or mesh?
Would one still observe forces of the same magnitude?
From what I understood, waves would still be bouncing yet the surface upon which a force can be applied, or a momentum be transferred to would be drastically reduced...
Somewhere , somehow, if this device really works, there must be a momentum transfer onto the frustum....
If it is uncertain what role the end plates play, why try dielectric materials, or materials with a high magnetic permeability (this subject got completely lost in the current discussion?) on the side walls of the frustum to see if any drag effect is in effect?
We really need to take a stand and not entertain further discussion of "pushing on virtual particles" or referring to the QV as a plasma. The overwhelming scientific consensus is that the quantum vacuum doesn't work this way.
Good. We are in violent agreement to self regulate this thread and keep pseudoscience out. Otherwise, this effort is lost.
...
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
The ball (photon) doesn't fall back down the well. There is nothing to give it back enough energy to do so. It dissipates in multiple reflections between the walls and the big end. They are not getting more out than they put in, so it does not violate conservation of energy. They are simply getting more NET momentum on one direction than in the other direction because there is more dissipation and attenuation in one direction than there is in the other. Dissipative systems are typically "not" conservative, loses prevent a true equal measure from occuring in both directions.
Todd D.
Classically, a dissipative system is conservative for both momentum and energy, it's just that for energy there is a (irreversible) conversion to a degraded form of energy, but there is no such thing as a mysterious part of total energy that would simply vanish. Even if not always convenient, an open system can be seen as part of a bigger closed system, and short of that the deltas total energy and total momentum of an open system can still be accounted, at least in principle, as integrated fluxes exchanged between open system and an outside.
My Newtonian ball of momentum pb can encounter an arbitrarily varying Force Fcb(t) of container on ball (vectors in bold). And dpb/dt=Fcb=-Fbc=-dpc/dt. That is instant conservation of momentum, and obviously integrating on successive instants just yields delta_pb=-delta_pc or delta_pb+delta_pc=0, conservation of momentum on any time interval whatever the shape of varying Force Fcb(t). Where and how quantitatively your system is showing an apparent breaking of CoM at an "instantaneous scale" dt ? Short of that, details of trajectory is just, ahem, arm waving for propulsion purpose (aka Dean drive).
...Yes, the problem is, however, how would this, quantitatively, result in a more efficient (thrust/PowerInput) propellant-less drive than a perfectly-collimated photon rocket.
At the "instantaneous scale" there are collisions between photons and atoms where momentum is transferred and it generates heat but not thrust. When the photons are injected their momentum is p1 and energy is E1. It can only conserve NET momentum if there is a 50/50 probability that momentum is absorbed in each direction, without generating ANY heat at all. As soon as things start getting hot, the probability is not 50/50 anymore, then some of the momentum is not being absorbed as thrust, but rather to heat up the metal. Therefore, the NET momentum in either direction will depend on the difference in the dissipation and attenuation, in each direction.
Todd D.
I know I'm new here but I've been in engineering for almost 50 years. The EM drive seems to parallel so many things I've seen in electronics and embrace harmonics and it got me thinking how it would compare to things like a YAGI antenna for gain buy linking them in series. Would you get a Q gain in thrust?https://www.youtube.com/watch?v=Wokn7crjBbA
Good. We are in violent agreement to self regulate this thread and keep pseudoscience out. Otherwise, this effort is lost.
1) Interesting how that presentation was just a few months ago. That was presented by the Chief Scientist NASA Ames. How things have changed, given the present official reaction by NASA and NASA Glenn regarding the efforts at NASA Eagleworks. (The "applications" section of the NSF article that generated so much controversy are old papers by Dr. White that he had published months and years ago).I know I'm new here but I've been in engineering for almost 50 years. The EM drive seems to parallel so many things I've seen in electronics and embrace harmonics and it got me thinking how it would compare to things like a YAGI antenna for gain buy linking them in series. Would you get a Q gain in thrust?https://www.youtube.com/watch?v=Wokn7crjBbA
Great thought!
I'm digging on this idea right now but more than Q it seems like the phasing has some profound effects as well. Not a lot of data there, but what little I've gleaned it looks like something I want to pursue. I've been refreshing my old vacuum tube/crystal radio school education so I can wrap my brain around it. I have some ideas but they are not ready to throw out here quite yet.
I found a little blurb in a presentation where Dr. White (Sonny) briefly mentioned one of the tests they were thinking of was to put another passive EM device behind the active one to see if they could discern a pattern. To me this sounded like an YAGI and a great idea. Stack them up like a YAGI I thought, phase them to increase thrust.
...Yes, the problem is, however, how would this, quantitatively, result in a more efficient (thrust/PowerInput) propellant-less drive than a perfectly-collimated photon rocket.
At the "instantaneous scale" there are collisions between photons and atoms where momentum is transferred and it generates heat but not thrust. When the photons are injected their momentum is p1 and energy is E1. It can only conserve NET momentum if there is a 50/50 probability that momentum is absorbed in each direction, without generating ANY heat at all. As soon as things start getting hot, the probability is not 50/50 anymore, then some of the momentum is not being absorbed as thrust, but rather to heat up the metal. Therefore, the NET momentum in either direction will depend on the difference in the dissipation and attenuation, in each direction.
Todd D.
Another fascinating observation that @frobnicat made early on, is that for photons (whether tunneling, dissipation or another mechanism) to end up producing a more efficient drive than a photon rocket, the photons would have to escape the EM Drive as tachyons, superluminally.
My intuition gave me patents (have more than a few) but the science gave me understanding. My intuition says that you'll find a solution, funding can happen and greater public exposure will help. On this point I will write my congressman and anyone else who can help push, cajole or twist an arm and I would urge anyone else to do. I have no doubt something is there and that something needs good science to resolve it. The investment is not big, but the ROI is the stars (well, maybe the local neighborhood). ;)
1) Interesting how that presentation was just a few months ago. That was presented by the Chief Scientist NASA Ames. How things have changed, given the present official reaction by NASA and NASA Glenn regarding the efforts at NASA Eagleworks. (The "applications" section of the NSF article that generated so much controversy are old papers by Dr. White that he had published months and years ago).
2) Unfortunately the tiny budget at NASA Eagleworks has prevented them from conducting the proposal to put another passive EM device behind the active one. Star-Drive posted some time ago that they didn't have another EM Drive to conduct the test :(
...
Where is the calculation for a photon rocket comparison? When calculating the photon rocket thrust was the input power used, or the input power multiplied by the Q? I don't think I've seen that yet. I seriously need to start keeping a spreadsheet of data, tests, results and discussions. It's too much to keep track of in my head.
I'm new here and I just thought I would post this video for you all. Its a very VERY sloppy experimental setup of something like the what people on this forum are talking about. The interesting thing here is the man in the video doesn't use end-plates and its quite a bit slimmer than the EM Drive. Here is the video:
youtube.com/watch?v=vcaOKX7Ko7w
What are some thoughts about the video posted?
Rough translation (From original in Russian):QuoteCreated Shawyer (EM Drive) engine is very easy and simple in its design . It provides the necessary thrust " by the oscillation of the microwaves inside the vacuum container ."
http: //hi-news.ru/technology/v-nasa-i ...
I decided that the system should not be closed
It is a waveguide with one end open. The Russian author points out (later in his Russian text) that he thinks that Shawyer, and others are wrong in using a closed cavity.
The reference (Cullen) given by Shawyer to support his theory also used in his experimental measurements of pressure, a cavity with one end open (with a transparent glass)
It is known that a microwave waveguide having one end open will display directional thrust, as the microwave photons escape the waveguide. The problem with the EM Drive is that it is a closed cavity, hence it cannot be explained solely based on Maxwell's equations. Something else is needed: General Relativity, QV, something else.
A waveguide with one end open will behave as a very inefficient photon rocket: thousands of times less thrust per power input than what is claimed in the EM Drive experiments.
Good. We are in violent agreement to self regulate this thread and keep pseudoscience out. Otherwise, this effort is lost.
This endeavour is by definition "pseudoscience". I.e. it defies all our logic and principles that we have previously and whole heartedly embraced. Space is an actual object and performs work on everything we observe. The "vacuum" does not exist and this experiment is proof of this statement. We must question everything that we have learned and realize that the truth may lie in "pseudoscience". This experiment reveals that we lack understanding of our physical reality and the "laws" we blindly accept as truth are evidence of this misunderstanding because if they were completely accurrate then we would have already solved the problem.
I'm wondering, in the context of dr. rodal's remark on Shawyer's theory, where he (Shawyer) poses that forces are to be observed on the ends only, what would happen if one or both ends were to be replace by Cullen type ring reflector or mesh?
Would one still observe forces of the same magnitude?
From what I understood, waves would still be bouncing yet the surface upon which a force can be applied, or a momentum be transferred to would be drastically reduced...
Somewhere , somehow, if this device really works, there must be a momentum transfer onto the frustum....
If it is uncertain what role the end plates play, why try dielectric materials, or materials with a high magnetic permeability (this subject got completely lost in the current discussion?) on the side walls of the frustum to see if any drag effect is in effect?
This device does really work and there need not be a momentum transfer onto the frustum because the momentum transfer is between the warp bubble and space-time itself. Remember, Dr. White's intention is to create a warp bubble where everything inside this warp bubble (the drive) are unperturbed.
...The waves are electromagnetic waves with photons at a microwave frequency. They can be Maser [ https://en.wikipedia.org/wiki/Maser ] which is very expensive -beyond the reach of the NASA researchers' budget- and whose goal would be unclear, given the present understanding.
Would it be possible to amplify the waves in the cavity, trying to create a high pressure scenario that perhaps could be an efficient "photon" rocket? Can these waves be pressurized?
...Totally random thought but what if y = ee is not random :) (e is like an encrypted message: its digits are in a random sequence, but it contains a huge amount of information, if one has the key :) )
...As it is now, my preference goes to Todd's theoretical model, simply because that's something i can still understand and it makes sense to me, as layman. Not sure if it is THE right theory, but at this stage we're in , that doesn't matter much...(yet)We are very lucky to have Todd and all other newcomers join our forum. It is delightful to see how clearly Todd writes about GR, and the flood of new ideas and experience being shared in this thread. All the pain and suffering resulting from the commingling of the NSF article with the fringe articles was well worth it if as a result of it we received a flood of new blood with fresh eyes and fresh brains on this matter :)
The laser light excited the pentacene molecules to an energy level known as a metastable state. Then a microwave passing through the crystal triggered the molecules to relax, releasing a cascade of microwaves of the same wavelength.
It was the same principle as an optical laser. "The signal that came out of it was huge," says Oxborrow, about a hundred million times as powerful as an existing maser. Alone in his lab, "I swore a lot and walked around the corridor about five times talking to myself".
I wholeheartedly agree with the intention of the smart people around here, helping the rest of us to filter the science from the chaff.You can call me Al ;D
Nevertheless, I assume there is going to be a break point: either the Emdrive proves to deliver some anomalous thrust or it doesn't.
If it does, such anomaly would maybe go against some of the scientific principles stated here (as very pointedly remarked by frobnicat et al).
But such proof by counterexample would need to be really overwhelming and repeatable in order to be accepted. Is that correct?
...My recollection (from running numerical examples at the time at which you were planning to run experiments with a Gunn diode) is that at large Xmn, with both m~n simultaneously highest, Xmn increases higher than f, so that
Really hadn't thought about it, but at large X, isn't f prop X ? and NT prop X^2/f^3 ??
Xmn (f) ~ f ^y where y>1
Need y>3/2 in order for thrust force to increase with frequency.
My recollection is that the thrust force predictions using your formula for the Gunn Diode frequency were much higher than the predictions of Shawyer and McCulloch.
EDIT: Also the calculations for Shawyer's Flight Thruster (which I recall was run at higher frequency: 3.85GHz, twice the frequency of NASA's EM Drive tests)
Is my memory correct ? (too bad that we don't have a good search function to look for things like that :( )
Can't remember either, that may have been before I did the units check and noticed the 1/f error (typo on post-it notes) in N (number of photons).
I should go back and set up a graphing program for these formulas. Cavity dimensions scale as 1/f just to add to the mess.
I never did get back to the cylindrical w/ dielectric case. Except for a uniform change, most dielectric surfaces need to include a reflection and you need an iterative program to solve them numerically. (wrote some of these for optical filter companies in the dim dark past) It would be nice to have an integral solution that could be optimized.
Just a note: CoM from spacial symmetry is thought to be local from present cosmology, or so I believe, really haven't checked.
Thanks for the response, and thank to all of you who even bother reading my posts. I'm so privileged to be here talking with minds like yours. I really do want to keep crack-pot and "pseudoscience" to a minimum, but I'm afraid I've not been classically trained. But I do have a passion & (very) open mind.
As for the Maser, what about this discovery: http://www.nature.com/news/microwave-laser-fulfills-60-years-of-promise-1.11199
Could NASA not handle something like this? I wish I could give NASA the DEA's budget... this is so frustrating.QuoteThe laser light excited the pentacene molecules to an energy level known as a metastable state. Then a microwave passing through the crystal triggered the molecules to relax, releasing a cascade of microwaves of the same wavelength.
It was the same principle as an optical laser. "The signal that came out of it was huge," says Oxborrow, about a hundred million times as powerful as an existing maser. Alone in his lab, "I swore a lot and walked around the corridor about five times talking to myself".
Seems like the goal, one of them anyway, could be to reduce the input energy? Also, presuming this drive is working as it seems that it does, and the fact that we don't understand it very well or at all, this could be one of those "Hobbyist/Hacker Hunches" (which is all I have to contribute at this time, sorry!).
Where is the calculation for a photon rocket comparison? When calculating the photon rocket thrust was the input power used, or the input power multiplied by the Q? I don't think I've seen that yet. I seriously need to start keeping a spreadsheet of data, tests, results and discussions. It's too much to keep track of in my head.Rodal, I appreciate the synopses you've posted in order to answer this, and the comparative work by NotSoSureOfIt also. It seems that, to within an order or so (and there's nothing especially accurate happening with the modelling of results yet), the thrust can be modelled as Q*(photon rocket).
If it works as a maser then it must have a reasonably high index at those frequencies (or it was in some sort of cavity) Too bad it wasn't frustrum shaped.
OK so it was inside a tuned cavity.
...Yes, the problem is, however, how would this, quantitatively, result in a more efficient (thrust/PowerInput) propellant-less drive than a perfectly-collimated photon rocket.
At the "instantaneous scale" there are collisions between photons and atoms where momentum is transferred and it generates heat but not thrust. When the photons are injected their momentum is p1 and energy is E1. It can only conserve NET momentum if there is a 50/50 probability that momentum is absorbed in each direction, without generating ANY heat at all. As soon as things start getting hot, the probability is not 50/50 anymore, then some of the momentum is not being absorbed as thrust, but rather to heat up the metal. Therefore, the NET momentum in either direction will depend on the difference in the dissipation and attenuation, in each direction.
Todd D.
Another fascinating observation that @frobnicat made early on, is that for photons (whether tunneling, dissipation or another mechanism) to end up producing a more efficient drive than a photon rocket, the photons would have to escape the EM Drive as tachyons, superluminally.
Where is the calculation for a photon rocket comparison? When calculating the photon rocket thrust was the input power used, or the input power multiplied by the Q? I don't think I've seen that yet. I seriously need to start keeping a spreadsheet of data, tests, results and discussions. It's too much to keep track of in my head.
All good questions that cannot be answered with the present state of knowledge. EM Drive researchers have operated with very tiny budgets.If it works as a maser then it must have a reasonably high index at those frequencies (or it was in some sort of cavity) Too bad it wasn't frustrum shaped.
OK so it was inside a tuned cavity.
The tuned cavity being a cube, correct? Like the attached image? Would feeding the output of the maser into a frustrum change Shawyer's findings? Would it have an effect on the perceived thrust at all? Would it be better to make the maser in a frustrum rather than feed the output into the resonant cavity?
Is there any reason this should not be further investigated in regards to an EM Drive?Yes, the reason is that NASA Eagleworks doesn't even have the money to test another EM Drive piggybacked in series, the only one they have was made in the living-room of one of the researchers. A MASER costs hundreds of thousands of dollars, which is way out of their tiny budget.
...Yes, the problem is, however, how would this, quantitatively, result in a more efficient (thrust/PowerInput) propellant-less drive than a perfectly-collimated photon rocket.
At the "instantaneous scale" there are collisions between photons and atoms where momentum is transferred and it generates heat but not thrust. When the photons are injected their momentum is p1 and energy is E1. It can only conserve NET momentum if there is a 50/50 probability that momentum is absorbed in each direction, without generating ANY heat at all. As soon as things start getting hot, the probability is not 50/50 anymore, then some of the momentum is not being absorbed as thrust, but rather to heat up the metal. Therefore, the NET momentum in either direction will depend on the difference in the dissipation and attenuation, in each direction.
Todd D.
Another fascinating observation that @frobnicat made early on, is that for photons (whether tunneling, dissipation or another mechanism) to end up producing a more efficient drive than a photon rocket, the photons would have to escape the EM Drive as tachyons, superluminally.
Where is the calculation for a photon rocket comparison? When calculating the photon rocket thrust was the input power used, or the input power multiplied by the Q? I don't think I've seen that yet. I seriously need to start keeping a spreadsheet of data, tests, results and discussions. It's too much to keep track of in my head.
There is, in classical interpretation of SR, no reason to multiply the thrust of a photon rocket by Q as the number of time a quantum of momentum carrier bounced around before leaving the rocket for good and living its own trajectory (by definition : as a real particle) is irrelevant. Only the momentum "lost" by a leaving particle in a direction is a "gained" momentum in the opposite direction for a spacecraft.
For a classical SR interpretation of what is possible for a deep space craft assuming no field/bath/mutable_vacuum to swallow and/or push on, see second half of this fascinating :D post ( 3/ ... ) (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1315118#msg1315118)
And the other way around, if a cavity is receiving a flux of particles, there is no way (classically) it can recover more nor less momentum than the initial amount entering the boundary, no matter the path and number and modality of interactions of particles with said cavity, if they are to end their lives within. And not only that would make the emitting system to transfer momentum with no more efficiency than using the equivalent of a photon rocket thrust to blow on a sail (unless it is sending tachyons), but if the sender of the flux is attached to the receiving cavity then the net momentum delta of the whole process is 0 (assuming nothing leaves).
Only between two different systems exchanging photons back and forth many times a transfer of momentum more efficient (by a factor Q) than the photon rocket limit can occur. This could be used to "beam" a force from system A to system B. But again, if system A and B are rigidly linked within a same craft, this is just a static force within the craft, so the Q factor won't amplify nothing useful. EM internal pressure inside a resonating cavity is proportional to Q but does not help to create net imbalance. And as soon as photons leave (if they leave), there can be net imbalance, but Q is not an amplifying factor of efficiency, there are not more photons leaving (for a given energy input) because they bounced many times before leaving.
I've scratched my head for 15 minutes trying to understand the points made in your previous post about asymmetric dissipation but this is not making sense for me so far, even trying hard to think "out of the box". Will try to address and ask for clarifications when time permits.
edit: blowing on a reflective sail a flux of photon actually allows the emitter to "transmit a force", for a given power, twice that of a photon rocket thrust (best case). Still irrelevant if emitter is rigidly linked to sail : perfectly absorbing sail -> 0 net thrust, perfectly reflecting and collimating sail -> thrust/power=1/c
...
Frankly, if you had a source of microwaves equal to Q*100W, that photon rocket would probably be more efficient than a frustum at exerting thrust because there are fewer losses.
Todd
@frobnicat:As you calculated, the internal energy is proportional to Q. The internal energy is dissipated into heat. So that again points toward a thermal effect. Vacuum someone says? Let's look at outgassing from the heated FR4
I totally agree that "Q*(photon rocket thrust)" is a nonsense piece of physics on the face of it, for the same reasons you elaborate. However, I was just pointing out that it simply seems to be a good experimental thrust predictor.
Which, of course, is completely weird if you take the thrust measurements as largely unflawed. And no, I don't know what it points to.
...There seems to be confusion here. No question internal energy is proportional to Q, for a given net power input. But this net power input is not clear...My bad. I had not thought it through. You are right, Q is actually the contrary of energy losses.
...Great graphing program !
I should go back and set up a graphing program for these formulas. Cavity dimensions scale as 1/f just to add to the mess.
...
As yet I haven't dipped my toe into the doubtless tasty maths of frustum mode frequencies as a function of frustum dimensions. It would seem best to use the most successful mode from an experimental POV. This would be the so-called TE2012 of EW? or something else? I'm talking about max thrust, which is really the only interesting metric at this stage.Just like everything else to do with the EM Drive very tortuous and controversial topic.
The more that Br'er Rabbit fights the Tar-Baby, the more entangled he becomes
I appreciate that there's no standard nomenclature for the frustum. What about Jang's mode? Shawyer's mode? EW actually gets the smallest N/W value of the three.Shawyer's modes here: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634741
...
Frankly, if you had a source of microwaves equal to Q*100W, that photon rocket would probably be more efficient than a frustum at exerting thrust because there are fewer losses.
Todd
Shawyer/PhtnRckt = 2 * Q * designFactor
McCulloch/PhtnRckt = Q * ((cavityLength/smallDiameter) - (cavityLength/bigDiameter))
hence
Shawyer/(Q *PhtnRckt) = 2 * designFactor
McCulloch/( Q * PhtnRckt) = ((cavityLength/smallDiameter) - (cavityLength/bigDiameter))
The predictive formulas therefore satisfy the "Todd conjecture"
(EmDriveThrustForce/(Q*EmDrivePowerInput) /(PhotonRocketThrust/ (Q*PhotonRocketPowerInput) < 1
equivalently
(EmDriveThrustForce/(EmDrivePowerInput) /(PhotonRocketThrust/ (PhotonRocketPowerInput) < 1
if and only if this condition is met:
Shawyer: designFactor < 0.5
McCulloch: ((cavityLength/smallDiameter) - (cavityLength/bigDiameter)) < 1
[notice that for smallDiameter approaching zero, as the frustum becomes a cone, the condition is not met]
(At first, rapid glance, the experimental results, seem to satisfy Todd's conjecture,although I have not checked them in detail)
Example:
Shawyer Experimental
Design Factor = 1.23205
does not satisfy condition designFactor< 1/2
but the experimental force is 1/2.5625 of what Shawyer's formula predicts, so the experiments do satisfy it:
(1/2.5625)/(1/2) = 0.78 which is less than 1, hence the experiment satisfies Todd's conjecture
See:
1) http://forum.nasaspaceflight.com/index.php?topic=36313.msg1302455#msg1302455
2) http://forum.nasaspaceflight.com/index.php?topic=29276.msg1276053#msg1276053
________
NOTE: we never got the exact geometry of the experiments from Shawyer (it is not given in his papers), so it was estimated to the best of the abilities of this group
Good. We are in violent agreement to self regulate this thread and keep pseudoscience out. Otherwise, this effort is lost.
This endeavour is by definition "pseudoscience". I.e. it defies all our logic and principles that we have previously and whole heartedly embraced. Space is an actual object and performs work on everything we observe. The "vacuum" does not exist and this experiment is proof of this statement. We must question everything that we have learned and realize that the truth may lie in "pseudoscience". This experiment reveals that we lack understanding of our physical reality and the "laws" we blindly accept as truth are evidence of this misunderstanding because if they were completely accurrate then we would have already solved the problem.
This is a strange definition of pseudoscience, and seems somewhat distant from its actual meaning. Pseudoscience involves false, or otherwise inaccurate claims of adherence to the scientific method.
@Einstein79:
I've noticed some commonality between your qualitative descriptions of a theory, and the idea of Mike McCullough. Coincidence or not, you should hook up
http://physicsfromtheedge.blogspot.com
I've read most of the links kindly provided about modes and energy but can find nothing against which to compare my cavity stored energy estimate of around 10-4 Joules for 50 W input.
McCullough has a paper "Newtonian gravitation from the uncertainty principle" which is very creative, but cannot possibly be right. Sitting next to me here is a Mettler mechanical balance that weighs down to half a Planck mass (10 ug). He asserts that anything smaller than mP does not gravitate.@Einstein79:
I've noticed some commonality between your qualitative descriptions of a theory, and the idea of Mike McCullough. Coincidence or not, you should hook up
http://physicsfromtheedge.blogspot.com
A coincidence indeed. I am reading his work now. He has a very interesting and unique approach but from what I read so far, he is still ignoring that space is an object. This "Unrah radiation" he uses is still based on virtual particles and not space itself and is only "created" (or seen) by moving objects. However, I particularly like his idea of a macroscopic Casimir effect because that certainly is a space-time anomaly.
If I were to use his ideas I would only use this "Unrah radiation" to describe the doppler shift of the space-time wave function as a result of the object moving. An object does not need to be moving in order for it to "feel space" and/or be perturbed by it. The Casimir effect is an excellent example of this. As far as the allowable nodes he wrote about, he kind of contradicted himself by stating that only certain wavelengths would be allowed between the object and the Rindler horizon because he assumed that the speed limit for light is what limited the transfer of information but then later suggests that the speed of light can vary under this approach. I find this contradictory because if the speed of light can vary then nothing would limit information exchange thereby allowing all possible wavelengths. There also is the phenomenon of quantum entanglement. In this situation, the transfer of information is not limited by light at all but is instantaneously transmitted directly through the space-time mechanism whether the particles are moving or not.
Thanks for finding that, I will keep reading to see what I can use.
Just finished a Design Factor frequency scanner as attached.I immediately noticed in your spreadsheet the following issues:
The spreadsheet scans the physical cavity parameters over a frequency range of 1GHz to 10GHz in 100kHz steps and plots the resultant Df using Dr Rodal's Df equation and the applied frequency. Also included are Thrust and Df calculators derived from Shawyers Thrust equation T = 2DfPoQ/c
The frequency for the highest Df found is displayed as well as the 2x & 3x harmonics of that frequency. From this data it appears Shawyer operates his cavities at either the 2x or 3x subharmonic of his Rf generator frequency. This is probably due to the availability of the frequency source.
Please throw rocks as I need this to be correct before designing my test cavity's parameters to be as close to those of the Flight Thruster and it's 3.85GHz design/operational frequency.
You can alter the cavity physical parameters in c2, c3 & c4 and watch the resultant change in freq to obtain max Df at either your prime or 2x or 3x harmonic frequency. Once you get close, you can adjust the start frequency and the step increment to get finer resolution. The scanner has 10,000 steps.
Attached updated version with a few more features, including the ability to select c velocity as in vacuum or atmosphere.
Your / Shawyer's Df equation has a frequency input, which if set to the Rf source frequency indicated, gives the Df value you indicated. My spreadsheet and yours agree.Just finished a Design Factor frequency scanner as attached.I immediately noticed in your spreadsheet the following issues:
The spreadsheet scans the physical cavity parameters over a frequency range of 1GHz to 10GHz in 100kHz steps and plots the resultant Df using Dr Rodal's Df equation and the applied frequency. Also included are Thrust and Df calculators derived from Shawyers Thrust equation T = 2DfPoQ/c
The frequency for the highest Df found is displayed as well as the 2x & 3x harmonics of that frequency. From this data it appears Shawyer operates his cavities at either the 2x or 3x subharmonic of his Rf generator frequency. This is probably due to the availability of the frequency source.
Please throw rocks as I need this to be correct before designing my test cavity's parameters to be as close to those of the Flight Thruster and it's 3.85GHz design/operational frequency.
You can alter the cavity physical parameters in c2, c3 & c4 and watch the resultant change in freq to obtain max Df at either your prime or 2x or 3x harmonic frequency. Once you get close, you can adjust the start frequency and the step increment to get finer resolution. The scanner has 10,000 steps.
Attached updated version with a few more features, including the ability to select c velocity as in vacuum or atmosphere.
1) On top of where it says
Shawyer Flight Thruster data:
Q = 60,000, Power In 440W, Thrust 0.17 N (170mN)
it says:
20452.053 Design Factor
Which is an extremely high number for a Design factor. Such a high number cannot correspond to a physically valued case. See Todd's prescription constraining such numbers http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373025#msg1373025
2) I used the original Design Factor spreadsheet I posted with the following input data (I suppose this is the data for the Flight Thruster ? since it has the corresponding frequency):
input unit value
big diameter m 0.2440
small diameter m 0.1400
cavity length m 0.1640
frequency Hz 3.8500E+09
and I obtain with the spreadsheet I posted:
output
Shawyer Design Factor (air) 0.277137
Shawyer Design Factor (vacuum) 0.277244
these Design Factor numbers, calculated by the original spreadsheet I posted, make sense for a physical situation and are much smaller than the number you have in your spreadsheet of 20452.053 (which is more than 70,000 times larger) which is too large to make physical sense.
See Todd's prescription constraining such numbers http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373025#msg1373025
3) I also notice that you have a long list of negative values of the Design Factor. For example this negative Design Factor appears next to my original format (underneath my original calculation for the Design Factor in Air -which is now erased-)
Shawyer Design Factor (vacuum) -1.645
Such a negative value is non-physical (a design factor value for a physically-valued case should not be negative)
See Todd's prescription constraining such numbers http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373025#msg1373025
References:
The original spreadsheet I posted: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829477
My message where the original spreadsheet appeared: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1371917#msg1371917
I know it's simple, but I have to ask. Is the torsion measurement equipment sensitive to shifts in the balance of the mounted drive?
In short, if the system were in fact acting as a sort of Maxwell's Daemon on the gases interior to the system, could this be perceived as "thrust?"
For the fixed frequency model our Dfs agree. However that frequency is not the optimal frequency to generate the highest Df for the cavity model....
Your / Shawyer's Df equation has a frequency input, which if set to the Rf source frequency indicated, gives the Df value you indicated. My spreadsheet and yours agree.
Being an engineer I asked myself, what if the Rf source frequency was altered to find which frequency generates the best Df? So I created the ability for the Df to be calculated for a wide range of frequencies, the resultant Df calculated/plotted and highest Df (as per the resolution of the incremental freq steps) obtained.
Have attached the latest version which shows the standard Df calc per cavity set of dimensions, and the best frequency and the resultant Df.
There are now 3 cavity data sets, the standard Df calc at the indicated frequency, the highest Df and the frequency that generated that Df.
By doing this series of calculations, to me it seems clear Shawyer operates his cavities at either the subharmonic 1/2 or 1/3 of best Df versus the Rf source.
It may be that by operating the cavity at 2x or 3x the optimal Df frequency, the Travelling Wave Shawyer speaks of is generated inside the cavity?
Maybe you might care to simulate a cavity optionally Df resonate at 1/2 the applied Rf frequency? Might be interesting.
BTW negative Dfs are generated if the applied frequency is lower than the optimal cavity Df frequency and positive if above. Simple to confirm.
1) Shawyer's Design Factor formula has a singularity (due to the expression in the denominator) that leads to negative values under certain non-physical conditions. Since the negative values (and the values approaching infinity at Shawyer's singularity) are non-physical I would not display them in a spreadsheet because they may lead to confusion.
2) What is your explanation for the Flight Thruster comparison? That value you have (more than 70,000 times higher than what my spreadsheet calculates) doesn't make sense. It appears you have an error in that calculation
2) I used the original Design Factor spreadsheet I posted with the following input data (I suppose this is the data for the Flight Thruster ? since it has the corresponding frequency):
input unit value
big diameter m 0.2440
small diameter m 0.1400
cavity length m 0.1640
frequency Hz 3.8500E+09
and I obtain with the spreadsheet I posted:
output
Shawyer Design Factor (air) 0.277137
Shawyer Design Factor (vacuum) 0.277244
these Design Factor numbers, calculated by the original spreadsheet I posted, make sense for a physical situation and are much smaller than the number you have in your spreadsheet of 20452.053 (which is more than 70,000 times larger) which is too large to make physical sense.
See Todd's prescription constraining such numbers http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373025#msg1373025
..
Again:
1) I would not display non-physical negative values in a graph (in my Mathematica code, I have an IF condiitional statement to deal with them). That's a personal choice
2) You have a big error in your calculation of 20452.053 design factor that you are not addressing in any of your replies. I haven't seen a reply acknowledging your error.
..
Again:
1) I would not display non-physical negative values in a graph (in my Mathematica code, I have an IF condiitional statement to deal with them). That's a personal choice
2) You have a big error in your calculation of 20452.053 design factor that you are not addressing in any of your replies. I haven't seen a reply acknowledging your error.
Use this data:
Big dia: 0.2797m
Small dia: 0.1588m
Length: 0.2286m
Frequency: 1.262GHz which is very close to the 1/2 subharmonic of 2.45GHz.
What is your Df?
These are the facts as I see them:..
Again:
1) I would not display non-physical negative values in a graph (in my Mathematica code, I have an IF condiitional statement to deal with them). That's a personal choice
2) You have a big error in your calculation of 20452.053 design factor that you are not addressing in any of your replies. I haven't seen a reply acknowledging your error.
Use this data:
Big dia: 0.2797m
Small dia: 0.1588m
Length: 0.2286m
Frequency: 1.262GHz which is very close to the 1/2 subharmonic of 2.45GHz.
What is your Df?
Well those dimensions are different from the dimensions that appear next to "Flight Thruster" in your original spreadsheet and the frequency is way too low, therefore I do get these non-physical values
Shawyer Design Factor (air) 20452.052793
Shawyer Design Factor (vacuum) -1329.537911
I don't understand why you are displaying that non-physical case.
When solving a physical problem I like to display values corresponding to physically valid cases.
I would not display non-physical values. But again that is a matter of choice. So there is no need to argue about it any further, now that I understand that you are displaying non-physical values.
Thank you :)
Waiting for your answer:..
Again:
1) I would not display non-physical negative values in a graph (in my Mathematica code, I have an IF condiitional statement to deal with them). That's a personal choice
2) You have a big error in your calculation of 20452.053 design factor that you are not addressing in any of your replies. I haven't seen a reply acknowledging your error.
Use this data:
Big dia: 0.2797m
Small dia: 0.1588m
Length: 0.2286m
Frequency: 1.262GHz which is very close to the 1/2 subharmonic of 2.45GHz.
What is your Df?
Well those dimensions are different from the dimensions that appear next to "Flight Thruster" in your original spreadsheet and the frequency is way too low, therefore I do get these non-physical values
Shawyer Design Factor (air) 20452.052793
Shawyer Design Factor (vacuum) -1329.537911
When solving a physical problem I like to display values corresponding to physically valid cases.
I would not display non-physical values. But again that is a matter of choice. So there is no need to argue about it any further, now that I understand that you are displaying non-physical values.
Thank you :)
...
These are the facts as I see them:
1) The Df alters with the Rf frequency and cavity configuration.
2) The value of the cavity Df effects the generated Thrust. T = 2 Df Po Q / c. Therefore Rf frequency effects Thrust.
3) There is a Rf frequency for every cavity configuration that will generate an infinite Df.
4) Rf frequencies below that optimal frequency generate negative Dfs.
5) Rf frequencies above that optimal frequency generate positive Dfs.
6) All tuned / resonant circuits have a peak resonate frequency.
7) High Q tuned / resonant circuits have a very sharp energy stored versus frequency curve.
Speculation:
1) The plots for Df versus frequency sure like what I would expect from a tuned circuit that has a very high Q being subjected to a spectrum sweep.
1) Shawyer appears to operate his Flight Thruster at an Rf input frequency of 3x the optimal cavity Df frequency.
2) I don't think that is coincidence.
Hi, Yesterday i received and tested a magnetron from a microwave oven.
Today i received the cooper and in a couple of hours i will expect to finish the frustum, will post the results in my website, where i started to post the progress of my work live: http://www.masinaelectrica.com/emdrive-independent-test/. If i do not encounter big problems i should test the drive in 3-4 hours.
Iulian
I know infinite values are impossible. Likewise negative Dfs. That was not the point....
These are the facts as I see them:
1) The Df alters with the Rf frequency and cavity configuration.
2) The value of the cavity Df effects the generated Thrust. T = 2 Df Po Q / c. Therefore Rf frequency effects Thrust.
3) There is a Rf frequency for every cavity configuration that will generate an infinite Df.
4) Rf frequencies below that optimal frequency generate negative Dfs.
5) Rf frequencies above that optimal frequency generate positive Dfs.
6) All tuned / resonant circuits have a peak resonate frequency.
7) High Q tuned / resonant circuits have a very sharp energy stored versus frequency curve.
Speculation:
1) The plots for Df versus frequency sure like what I would expect from a tuned circuit that has a very high Q being subjected to a spectrum sweep.
1) Shawyer appears to operate his Flight Thruster at an Rf input frequency of 3x the optimal cavity Df frequency.
2) I don't think that is coincidence.
The Design Factor is an approximate equation that Shawyer presented but that he never mathematically formally derived. It has been criticized by a large number of physicists and engineers.
Shawyer's Design Factor mathematical formula contains a singularity for finite values of the geometrical dimensions and finite values of frequency. The infinite values at the singularity and the negative values are obviously non-physical: they correspond to values that cannot take place in our physical world.
Hence instead of writing (for example):
3) There is a Rf frequency for every cavity configuration that will generate an infinite Df.
That may be misinterpreted as if it would be physically possible for this to occur, and that Shawyer's approximation is an accurate model for reality over the whole range of input variables, I would instead write that there is a finite frequency at which Shawyer's expression blows up due to a singularity in Shawyer's approximaton.
As an analogy, McCulloch's expression blows up for the small diameter approaching zero. I brought this up to the attention of McCulloch and McCulloch readily admits that this is due to an approximation he made in his 1-D formula. Obviously, a pointy cone would not behave the way that McCulloch's formula would predict: that limit is a non-physical situation outside the approximation limits of McCulloch.
Similarly it maybe that Shawyer's expression is an engineering approximation to certain unknown ranges of dimensions and frequencies. Clearly, very large values of Shawyer's Design Factor much exceeding 1/2 and any negative values are non-physical (as brought up by Todd, separately).
It may also very well be that the singularity in Shawyer's Design Factor is due to the cut-off condition. If that is the case, how accurate it is for engineering purposes and for what range of input values, remains to be assessed.
Yup.Hi, Yesterday i received and tested a magnetron from a microwave oven.
Today i received the cooper and in a couple of hours i will expect to finish the frustum, will post the results in my website, where i started to post the progress of my work live: http://www.masinaelectrica.com/emdrive-independent-test/. If i do not encounter big problems i should test the drive in 3-4 hours.
Iulian
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
...
I know infinite values are impossible. Likewise negative Dfs. That was not the point.
The point is the Df equation, applied to a variable frequency, shows there is an ideal frequency that will generate the best cavity Df. Driving the cavity with some chosen frequency, like 2.45GHZ will probably NOT make anything happen. Like trying to drive a tuned LC circuit with a frequency far away from it's resonate frequency. Waste of time. Likewise driving the cavity with the calculated best Df frequency will probably do the same thing. No thrust in the real world.
What the exercise shows is that the Rf generator driving the cavity should be operating 2x or 3x the best Df cavity frequency and that Rf frequency generating system must be able to vary the driving frequency so to search for the best frequency in the real world. The spreadsheet give me a starting place and an understand the cavity best Df frequency should be 1/2 or 1/3 the applied Rf frequency.
To me as an engineer starting a replication of the Flight Thruster and associated variable Rf generation system, it is very new and valuable information. This is all related to real world engineering (building actual hardware) to give the best chance of generating thrust.
To assisting theory development, well it may not be of much value.
Shawyer (to my knowledge) has never provided all three geometrical dimensions of the truncated cone. Hence one of the dimensions (the diameter of the small base) has to be estimated (as per the attached file, parametrized, or estimated from images, as done by @aero and others). Since Shaywer has not provided all three dimensions, there is uncertainty as to what he actually did and why
@aero had correspondence with Shawyer asking for the dimension of the small diameter, to my knowledge Shawyer cryptically answered "small base diameter chosen on the basis of the cut-off frequency" (hence still unknown how close to the cutoff wavelength was the small base diameter.
[...
Dr. Rodal, keeping track of these developments, it always seems to me that you and the other active participants here are in a position of "archaeologists", trying to retrace the somewhat mysterious and obscure steps by Shawyer. Maybe I missed the relevant information somewhere down the thread, but shouldn't it be easy to acquire the needed information if Shawyer has a working drive AND supposedly has already been through a lot of what is being now recreated / retraced here (again)? It's not that he has disappeared off the planet (or has he? ;) )...
Thanks for that data....
I know infinite values are impossible. Likewise negative Dfs. That was not the point.
The point is the Df equation, applied to a variable frequency, shows there is an ideal frequency that will generate the best cavity Df. Driving the cavity with some chosen frequency, like 2.45GHZ will probably NOT make anything happen. Like trying to drive a tuned LC circuit with a frequency far away from it's resonate frequency. Waste of time. Likewise driving the cavity with the calculated best Df frequency will probably do the same thing. No thrust in the real world.
What the exercise shows is that the Rf generator driving the cavity should be operating 2x or 3x the best Df cavity frequency and that Rf frequency generating system must be able to vary the driving frequency so to search for the best frequency in the real world. The spreadsheet give me a starting place and an understand the cavity best Df frequency should be 1/2 or 1/3 the applied Rf frequency.
To me as an engineer starting a replication of the Flight Thruster and associated variable Rf generation system, it is very new and valuable information. This is all related to real world engineering (building actual hardware) to give the best chance of generating thrust.
To assisting theory development, well it may not be of much value.
As to why Shawyer is using a particular excitation frequency I suggest that you use your spreadsheet to check the above vs. the calculated natural frequencies and mode shapes here:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634741
(see in the slide the drawing insert detail containing the two dimensions (the diameter of the big base and the length of the truncated cone) given by Shawyer while the third dimension (the diameter of the small base) of the truncated cone is parametrized on the horizontal axis (ranging from a pointy cone to a cylinder) to ascertain its correct value)
Shawyer (to my knowledge) has never provided all three geometrical dimensions of the truncated cone. Hence one of the dimensions (the diameter of the small base) has to be estimated (obtained from the inverse expression for the Design Factor -when Shawyer has provided the Design Factor, parametrized as per the attached file, or estimated from images, as done by @aero and others). Since Shaywer has not provided all three dimensions, there is uncertainty as to what he actually did and why
@aero had correspondence with Shawyer asking for the dimension of the small diameter, to my recollection Shawyer cryptically answered "small base diameter chosen on the basis of the cut-off frequency" (hence still unknown how close to the cutoff wavelength was Shawyer's chosen small base diameter).
[...
Dr. Rodal, keeping track of these developments, it always seems to me that you and the other active participants here are in a position of "archaeologists", trying to retrace the somewhat mysterious and obscure steps by Shawyer. Maybe I missed the relevant information somewhere down the thread, but shouldn't it be easy to acquire the needed information if Shawyer has a working drive AND supposedly has already been through a lot of what is being now recreated / retraced here (again)? It's not that he has disappeared off the planet (or has he? ;) )...
Personally, more than an "archaeologist" I feel like somebody dealing with the tar-baby in Uncle Remus: The more that Br'er Rabbit fights the Tar-Baby, the more entangled he becomes. :)
(http://i.ytimg.com/vi/u9svyIqwbOg/hqdefault.jpg)
As noted @aero (hat tip to him) already made a valiant effort to obtain the geometrical data from Shawyer. It has already been pointed out that people in present e-mail communication with Shawyer as well as others doing do-it-yourself can similarly attempt to obtain such data directly from him, if so interested.
[...
Dr. Rodal, keeping track of these developments, it always seems to me that you and the other active participants here are in a position of "archaeologists", trying to retrace the somewhat mysterious and obscure steps by Shawyer. Maybe I missed the relevant information somewhere down the thread, but shouldn't it be easy to acquire the needed information if Shawyer has a working drive AND supposedly has already been through a lot of what is being now recreated / retraced here (again)? It's not that he has disappeared off the planet (or has he? ;) )...
Personally, more than an "archaeologist" I feel like somebody dealing with the tar-baby in Uncle Remus: The more that Br'er Rabbit fights the Tar-Baby, the more entangled he becomes. :)
(http://i.ytimg.com/vi/u9svyIqwbOg/hqdefault.jpg)
[...
Dr. Rodal, keeping track of these developments, it always seems to me that you and the other active participants here are in a position of "archaeologists", trying to retrace the somewhat mysterious and obscure steps by Shawyer. Maybe I missed the relevant information somewhere down the thread, but shouldn't it be easy to acquire the needed information if Shawyer has a working drive AND supposedly has already been through a lot of what is being now recreated / retraced here (again)? It's not that he has disappeared off the planet (or has he? ;) )...
Personally, more than an "archaeologist" I feel like somebody dealing with the tar-baby in Uncle Remus: The more that Br'er Rabbit fights the Tar-Baby, the more entangled he becomes. :)
(http://i.ytimg.com/vi/u9svyIqwbOg/hqdefault.jpg)
Haha, thanks for this analogy. :) So let's hope all mysteries will be solved before anyone gets thrown into the Briar Patch... (pun so very much intended ;) ).
1) I have not read it in a long long time :), but as I recall Br'er Rabbit wanted to trick whoever caught him into throwing him into the Briar Patch, which is where he really wanted to be
2) I recall this better: the Ba'ku planet (in Star Trek's Briar Patch) is effectively a fountain of youth, so not a bad place to be either :)
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The Demonstrator EM Drive has a stepper motor outside the small end of the cavity. It physically adjust a cavity parameter (maybe length), via the gears and stepper motor, to obtain internal resonance with the applied Rf frequency. This takes time................
Having dealt with such technical subjects as Br'er Rabbit, the Tar-Baby, the Briar Patch, and the Ba'ku planet, we embark now into the more mundane world of Shawyer's experimental data. Please observe the attached image of Shawyer's Demonstrator Engine Data. Please notice the huge difference between the onset of the Power signal trace (vs. time) and the Down and Up thrust force signals vs. time. Note the time (from onset to reaching the first plateau or knee of the curve) is about ~20 sec.
Recall that for NASA Eagleworks tests this delay is ~2 sec (about 10 times less).
QUESTION 1: What is responsible for the huge time delay in Shaywer's force signal traces? For NASA Eagleworks this delay represents about ~4*10^9 electromagnetic wave cycles. For Shawyer this represents ~33*10^9 cycles.
Clearly, this huge number of cycles has nothing to do with the Quantum Vacuum, or the speed of light, or the time required for a resonant cavity to reach steady state in standing waves.
Is this time delay (20 sec) due to a time delay associated with a Q-multiplier effect ?
Is the time delay mainly due to the phase shift settling with time ? (due to Shawyer working with a Q multiplier setup having a Q=X times multiplier with feedback, having a phase shift narrow in frequency). (hat tip to @Notsosureofit for the explanatory hint, any misinterpretation of which is mine).
QUESTION 2: What is responsible for the time delay in Shaywer's force signal traces after the power is turned off?
Note: quotes used to call attention to this message in case they have quotes linked to e-mail message forum notifications.
Reference: http://www.emdrive.com/IAC-08-C4-4-7.pdf
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not.
The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.
Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
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...
Back a ways there existed in woo land something called a "Slepian Drive". Same guy?
https://groups.yahoo.com/neo/groups/Stardrive1/conversations/topics/3910
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not.
The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.
Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
Thank you. I agree with you :)
Early on in this thread, there was a lot of discussion of potential spaceflight applications which could be enabled by emdrives if the tech were to be viable. Here is an opportunity to roll some of that discussion into the design of the "challenge criteria" for an XPRIZE.I don't think you can begin to design any sort of mission until you know the equation of motion in free space.
http://forum.nasaspaceflight.com/index.php?topic=37563.0
http://www.xprize.org/about/what-is-an-xprize
There's still the issue of drifting off tune with temperature
The EM Drive Demonstrator was feed via a waveguide from a magnetron Rf source, not via coax. You can see the magnetron & waveguide in these 2 shots. Assume that connector is for feedback sense.From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
(Ques 1):
QUESTION 1: What is responsible for the huge time delay in Shaywer's force signal traces? For NASA Eagleworks this delay represents about ~4*10^9 electromagnetic wave cycles. For Shawyer this represents ~33*10^9 cycles.
Clearly, this huge number of cycles has nothing to do with the Quantum Vacuum, or the speed of light, or the time required for a resonant cavity to reach steady state in standing waves.
Is this time delay (20 sec) due to a time delay associated with a Q-multiplier effect ?
Is the time delay mainly due to the phase shift settling with time ? (due to Shawyer working with a Q multiplier setup having a Q=X times multiplier with feedback, having a phase shift narrow in frequency). (hat tip to @Notsosureofit for the explanatory hint, any misinterpretation of which is mine).
QUESTION 2: What is responsible for the time delay in Shaywer's force signal traces after the power is turned off?
Note: quotes used to call attention to this message in case they have quotes linked to e-mail message forum notifications.
Reference: http://www.emdrive.com/IAC-08-C4-4-7.pdf
There's still the issue of drifting off tune with temperatureIs why the Rf frequency is adjusted via a feedback loop as used in the Flight Thruster.
Early on in this thread, there was a lot of discussion of potential spaceflight applications which could be enabled by emdrives if the tech were to be viable. Here is an opportunity to roll some of that discussion into the design of the "challenge criteria" for an XPRIZE.I don't think you can begin to design any sort of mission until you know the equation of motion in free space.
http://forum.nasaspaceflight.com/index.php?topic=37563.0
http://www.xprize.org/about/what-is-an-xprize
There's still the issue of drifting off tune with temperature
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not.
The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.
Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
Thank you. I agree with you :)
If that stub extends inside the frustum, that would explain why he put the input at the big end. I still say, it should be at the small end to avoid perturbing the harmonics.
Todd
That also makes sense to me.There's still the issue of drifting off tune with temperature
... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.
Todd
Forgive me for interrupting, but with pulsing, do you mean Pulse Width Modulation or PWM?That also makes sense to me.There's still the issue of drifting off tune with temperature
... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.
Todd
Separately, but interestingly the Serrano field effect device tested by Dr. White displayed the highest thrust/InputPower of any device, yet it only showed very short time impulses (like Dirac Delta Functions) instead of steady state operation (although to me its principle of operation is very different from the EM Drive, Dr. White classified this device also as a Q-thuster).
Shawyer feed it with a magnetron as that was what was available and what he used on the 1st test of principal EM Drive (attached) which was fed via a waveguide from the middle. The coax connector is for sense. You can see the waveguide behind the EmDrive.From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not.
The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.
Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
Thank you. I agree with you :)
If that stub extends inside the frustum, that would explain why he put the input at the big end. I still say, it should be at the small end to avoid perturbing the harmonics.
Todd
Somebody else pointed out that Shawyer's Demonstrator was feed via a waveguide instead of via coax. Does that make any difference to your point that feeding should preferentially occur (if possible) at the small end to avoid perturbing harmonics? In other words do you think that feeding with a waveguide avoids perturbing harmonics and therefore if one feeds with a waveguide (fed upstream from a magnetron) you could just as well feed the waveguide at the big end ?
Have spoken with Hector Serrano. The SFE device EW tested produced torque pulses, not linear thrust. He is currently testing a linear version.That also makes sense to me.There's still the issue of drifting off tune with temperature
... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.
Todd
Separately, but interestingly the Serrano Field Effect Boeing Darpa device tested by Dr. White displayed the highest thrust/InputPower of any device, yet it only showed very short time impulses (like Dirac Delta Functions) instead of steady state operation (although to me its principle of operation is very different from the EM Drive, Dr. White classified this device also as a Q-thuster).
This is the text for Boeing/DARPA in slide 40 of Dr. White's presentation (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ):
<<SFE Test Article at JSC
In 2013, Boeing/DARPA sent Eagleworks Lab an SFE test article for testing and evaluation
Evaluation of the test article in and out of a Faraday Shield performed from Feb through June 2013.
• There is a consistent transient thrust at device turn-on and turn-off that is consistent with Qthruster physics
• The magnitude of the thrust scaled approximately with the cube of the input voltage (20-110uN).
• The magnitude of the thrust is dependent on the AC content of the turn-on and turn-off pulse
• Specific force of transient thrust was in the ~1- 20 N/kW range.
~20-110 uN Thrust Pulses
Specific Force ~1-20N/kW>>
NASA Eagleworks also provided this information in a 2013 Newsletter, which is available in the Internet from this link: https://xa.yimg.com/kq/groups/86787010/513081407/name/Eagleworks+Newsletter+2013.pdf
that reads:
<<NASA/Boeing/SFE Campaign: Boeing/DARPA sent Eagleworks Lab an SFE test article for testing and
evaluation. The guest thruster was evaluated in numerous test configurations using varying degrees of
Faraday shielding and vacuum conditions. Observations show that there is a consistent transient thrust
at device turn-on and turn-off that is consistent with Q-thruster physics. The magnitude of the thrust
scaled approximately with the cube of the input voltage (20-110uN). The magnitude of the thrust is
dependent on the AC content of the turn-on and turn-off pulse. Thrust to power of transient thrust was
in the ~1-20 N/kW range
Yes, that's twenty Newtons per kiloWatt on the upper range
...
I know infinite values are impossible. Likewise negative Dfs. That was not the point.
The point is the Df equation, applied to a variable frequency, shows there is an ideal frequency that will generate the best cavity Df. Driving the cavity with some chosen frequency, like 2.45GHZ will probably NOT make anything happen. Like trying to drive a tuned LC circuit with a frequency far away from it's resonate frequency. Waste of time. Likewise driving the cavity with the calculated best Df frequency will probably do the same thing. No thrust in the real world.
What the exercise shows is that the Rf generator driving the cavity should be operating 2x or 3x the best Df cavity frequency and that Rf frequency generating system must be able to vary the driving frequency so to search for the best frequency in the real world. The spreadsheet give me a starting place and an understand the cavity best Df frequency should be 1/2 or 1/3 the applied Rf frequency.
To me as an engineer starting a replication of the Flight Thruster and associated variable Rf generation system, it is very new and valuable information. This is all related to real world engineering (building actual hardware) to give the best chance of generating thrust.
To assisting theory development, well it may not be of much value.
As to why Shawyer is using a particular excitation frequency I suggest that you use your spreadsheet to check the above vs. the calculated natural frequencies and mode shapes here:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634741
(see in the slide the drawing insert detail containing the two dimensions (the diameter of the big base and the length of the truncated cone) given by Shawyer while the third dimension (the diameter of the small base) of the truncated cone is parametrized on the horizontal axis (ranging from a pointy cone to a cylinder) to ascertain its correct value)
Shawyer (to my knowledge) has never provided all three geometrical dimensions of the truncated cone. Hence one of the dimensions (the diameter of the small base) has to be estimated (obtained from the inverse expression for the Design Factor -when Shawyer has provided the Design Factor, parametrized as per the attached file, or estimated from images, as done by @aero and others). Since Shaywer has not provided all three dimensions, there is uncertainty as to what he actually did and why
@aero had correspondence with Shawyer asking for the dimension of the small diameter, to my recollection Shawyer cryptically answered "small base diameter chosen on the basis of the cut-off frequency" (hence still unknown how close to the cutoff wavelength was Shawyer's chosen small base diameter).
How can the principle of operation of the ring laser gyroscope be compared to the principle of operation of EM Drive thrust, escapes me...
Serrano's 0.02 N/W means breakeven speed is only 100 m/s = 2/kAccording to Serrano, the device EW tested only produces rotary torque forces, not linear force. So could spin a spacecraft around it's CG but can't alter its velocity.
Forgive me for interrupting, but with pulsing, do you mean Pulse Width Modulation or PWM?That also makes sense to me.There's still the issue of drifting off tune with temperature
... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.
Todd
Separately, but interestingly the Serrano field effect device tested by Dr. White displayed the highest thrust/InputPower of any device, yet it only showed very short time impulses (like Dirac Delta Functions) instead of steady state operation (although to me its principle of operation is very different from the EM Drive, Dr. White classified this device also as a Q-thuster).
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.
Todd D.
Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850
It seems to have the feed near the big diameter end.
Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not.
The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.
Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
Thank you. I agree with you :)
If that stub extends inside the frustum, that would explain why he put the input at the big end. I still say, it should be at the small end to avoid perturbing the harmonics.
Todd
Somebody else pointed out that Shawyer's Demonstrator was feed via a waveguide instead of via coax. Does that make any difference to your point that feeding should preferentially occur (if possible) at the small end to avoid perturbing harmonics? In other words do you think that feeding with a waveguide avoids perturbing harmonics and therefore if one feeds with a waveguide (fed upstream from a magnetron) you could just as well feed the waveguide at the big end ?
Funny. I suggested PWM like 20-25 pages ago... ::)Forgive me for interrupting, but with pulsing, do you mean Pulse Width Modulation or PWM?That also makes sense to me.There's still the issue of drifting off tune with temperature
... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.
Todd
Separately, but interestingly the Serrano field effect device tested by Dr. White displayed the highest thrust/InputPower of any device, yet it only showed very short time impulses (like Dirac Delta Functions) instead of steady state operation (although to me its principle of operation is very different from the EM Drive, Dr. White classified this device also as a Q-thuster).
Yes. Ramp it up to peak thrust and let it exponentially decay back to zero... and Repeat. Since it can't spend more than the input power supplies and remain in steady state operation, and we already know that the input power will only provide uN of thrust. Higher thrust cannot be sustained at steady state operation. Higher thrust levels can only be momentary, and will quickly decay to nothing when output exceeds input.
Todd
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The larger the Q, the larger the number of photons that can be red-shifted into attenuation in response to acceleration (and presumably providing “thrust” in an attempt to counter said acceleration when in "generator" mode). A similar thought experiment applies to the opposite end plate moving "towards" the rest frame, which should introduce a blue shift. How does blue or red shifting correlate to "thrust"? Or is such an observation merely another Red Herring? I have no idea...
...
Why has no one noticed superconducting resonant cavities floating or ripping themselves apart due to supposed EM drive thrust effects?
Answer: no EM drive thrust possible within a symmetrical resonant cavity
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
I was discussing this last night and we made some interesting observations. In a variable dielectric, like in the frustum, when the waves are accelerating to a higher group velocity, they are losing momentum. This momentum is lost to the material "in the direction of the wave". It is similar to frame dragging. The wave is losing energy trying to drag the waveguide or the dielectric with it.
After the wave is reflected, it again tries to drag the dielectric or frustum with it, and this time it meets more resistance. It becomes an evanescent wave and decays faster.
I do not believe a small end cap is needed and the frustum should taper all the way down to the wave guide feeding it. The reflected waves cannot reach the small plate. That's what the thermal images show as well. Most of the energy I think should be trapped at the big end.
Todd D.
Looking for a mechanical analogy :
Let's play with a bended pipe and a ball rolling in it. The pipe can constrain the ball to various path, it can rise or fall, at various steepness. Height of the pipe at a given location defines gravitational potential energy of the ball there. The ball is launched with a given velocity, and then turns around the pipe if it is a closed circuit, or goes back and forth if the two ends of the pipe are high enough, should make no difference.
Assuming no friction, the ball goes-on forever. When rising the ball loses kinetic energy, slows, and imparts momentum to the pipe. When on the return path (different part of pipe if circuit path or same part of pipe if going back and forth), the same delta height will make ball regain same kinetic energy as lost when rising, accelerate, and imparts momentum again. When taking curves, ball also imparts momentum on pipe. Integrating all those momentum exchanges on a cycle yields 0 net momentum. Not depending on path details.
Assuming a closed circuit path and friction (dry, viscous, magnetic... whatever dissipative interaction), including parts with low friction (forth) and parts with high friction (back) and arbitrary height profile (potential well whatever). After a number of cycles the ball will come to rest. Integrating all the momentum exchanges of ball on pipe (changes of height, curves, friction) will yield a total momentum equal to the initial momentum of the ball when launched. Not depending on path details and what parts are more or less dissipative.
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
The ball (photon) doesn't fall back down the well. There is nothing to give it back enough energy to do so. It dissipates in multiple reflections between the walls and the big end. They are not getting more out than they put in, so it does not violate conservation of energy. They are simply getting more NET momentum on one direction than in the other direction because there is more dissipation and attenuation in one direction than there is in the other. Dissipative systems are typically "not" conservative, loses prevent a true equal measure from occuring in both directions.
Todd D.
...
@WarpTech or other proponents of "dependence of the effect on acceleration", please run the numbers. What would be the acceleration of frustum needed to really drift out of bandwidth for Q around 10000 or otherwise reach a magnitude significant to behaviour of waves inside ?
@ RODAL
Just got a minute but from your p expression;
If L1/c1 = L2/c2
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
might be a solution ??
Got to check the thinking later.
Night !
I find your previous expression
del f = ( f/(2*c^2)) * (c1^2-c2^2)
more physically appealing, since it goes to zero for equal dielectric constants, regardless or their dielectric length,
while on the other hand
del f = (1/2*f)*((c1*c2)/(L1*L2))*b^2*((1/dD1^2)-(1/dD2^2))
goes to zero for equal dielectric lengths, regardless of their dielectric constants.
The previous expression is only valid approximation for a "uniformly varying dielectric". There is no L1 and L2 in that case.
What do you think might maximize the second expression ? (valid only for L1/c1 = L2/c2 )
I was discussing this last night and we made some interesting observations. In a variable dielectric, like in the frustum, when the waves are accelerating to a higher group velocity, they are losing momentum. This momentum is lost to the material "in the direction of the wave". It is similar to frame dragging. The wave is losing energy trying to drag the waveguide or the dielectric with it.
After the wave is reflected, it again tries to drag the dielectric or frustum with it, and this time it meets more resistance. It becomes an evanescent wave and decays faster.
I do not believe a small end cap is needed and the frustum should taper all the way down to the wave guide feeding it. The reflected waves cannot reach the small plate. That's what the thermal images show as well. Most of the energy I think should be trapped at the big end.
Todd D.
Looking for a mechanical analogy :
Let's play with a bended pipe and a ball rolling in it. The pipe can constrain the ball to various path, it can rise or fall, at various steepness. Height of the pipe at a given location defines gravitational potential energy of the ball there. The ball is launched with a given velocity, and then turns around the pipe if it is a closed circuit, or goes back and forth if the two ends of the pipe are high enough, should make no difference.
Assuming no friction, the ball goes-on forever. When rising the ball loses kinetic energy, slows, and imparts momentum to the pipe. When on the return path (different part of pipe if circuit path or same part of pipe if going back and forth), the same delta height will make ball regain same kinetic energy as lost when rising, accelerate, and imparts momentum again. When taking curves, ball also imparts momentum on pipe. Integrating all those momentum exchanges on a cycle yields 0 net momentum. Not depending on path details.
Assuming a closed circuit path and friction (dry, viscous, magnetic... whatever dissipative interaction), including parts with low friction (forth) and parts with high friction (back) and arbitrary height profile (potential well whatever). After a number of cycles the ball will come to rest. Integrating all the momentum exchanges of ball on pipe (changes of height, curves, friction) will yield a total momentum equal to the initial momentum of the ball when launched. Not depending on path details and what parts are more or less dissipative.
I know a photon is not a ball but my question is, in "Newtonian layman's terms" how does the line of thinking you are developing making that analogy not valid, i.e. imply apparent deviation from conservation of momentum ?
The ball (photon) doesn't fall back down the well. There is nothing to give it back enough energy to do so. It dissipates in multiple reflections between the walls and the big end. They are not getting more out than they put in, so it does not violate conservation of energy. They are simply getting more NET momentum on one direction than in the other direction because there is more dissipation and attenuation in one direction than there is in the other. Dissipative systems are typically "not" conservative, loses prevent a true equal measure from occuring in both directions.
Todd D.
Come to think of it, it is not particularly surprising that a gradient is more easily interpreted in the comoving frame than in covariant form: dissipative phenomena are by nature alien to covariance.
They are associated with the production of entropy, they have a thermodynamical arrow of time.
...
@WarpTech or other proponents of "dependence of the effect on acceleration", please run the numbers. What would be the acceleration of frustum needed to really drift out of bandwidth for Q around 10000 or otherwise reach a magnitude significant to behaviour of waves inside ?
I read it in Shawyer's recent paper, he simulated it on a computer. I don't have that type of software. I've been wishing I did for decades. Since the system moves by attenuation and dissipation, the photons lose momentum and are red-shifted, while the frustum either gains momentum or gains heat from them.
You're correct, that the momentum it gains from the photons is in the direction of the photons, but results from the difference in the attenuation in each direction. The photons lose more momentum moving inward than moving outward, because they become evanescent waves. They do not increase their energy, except what they can take away from the frustum.
So I see it like ringing a bell. It is the exponential decay from a higher energy state that is giving the thrust. Attempting to make the Q very high to sustain resonance requires reducing the losses, but it is the losses that give it thrust. So... Shawyer increases the angle to make it more like a pill box. Anything over pi/6 is very close to a pill box. Then it should have a higher Q, but it should also have less efficient use of it.
If a photon rocket is: F/P = 1/c
and the Frustum is: F/P ~ Q/c x pulse width
Design efficiency should then target: (F*c)/(P*Q) = 1 but in practice < 1
This would imply maximizing thrust with a lower value of Q, i.e., we do not want to maximize Q, we want to maximize asymmetry in the attenuation, which is what I'm working on at the moment.
Best Regards,
Todd
...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
From what I gather a magnetron source is full of harmonics and subharmonics...one called it "dirty" which is a good visual... spectrum-wise.
...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
I've been wondering about that, and also it looks like this has a high reflected, so feeding it with a 4 port circulator and running the reflected back into antenna 2, and it's reflected into antenna 3.
I was hoping to build a mini EmDrive using modified intruder alarm (22 GHz) modules as these can be tuned by simply adjusting the voltage and physical dimensions of the Gunn diodes resonant cavity.On reflection, not so hot. Only about 200 mW from these things.
...
@WarpTech or other proponents of "dependence of the effect on acceleration", please run the numbers. What would be the acceleration of frustum needed to really drift out of bandwidth for Q around 10000 or otherwise reach a magnitude significant to behaviour of waves inside ?
I read it in Shawyer's recent paper, he simulated it on a computer. I don't have that type of software. I've been wishing I did for decades. Since the system moves by attenuation and dissipation, the photons lose momentum and are red-shifted, while the frustum either gains momentum or gains heat from them.
You're correct, that the momentum it gains from the photons is in the direction of the photons, but results from the difference in the attenuation in each direction. The photons lose more momentum moving inward than moving outward, because they become evanescent waves. They do not increase their energy, except what they can take away from the frustum.
So I see it like ringing a bell. It is the exponential decay from a higher energy state that is giving the thrust. Attempting to make the Q very high to sustain resonance requires reducing the losses, but it is the losses that give it thrust. So... Shawyer increases the angle to make it more like a pill box. Anything over pi/6 is very close to a pill box. Then it should have a higher Q, but it should also have less efficient use of it.
If a photon rocket is: F/P = 1/c
and the Frustum is: F/P ~ Q/c x pulse width
Design efficiency should then target: (F*c)/(P*Q) = 1 but in practice < 1
This would imply maximizing thrust with a lower value of Q, i.e., we do not want to maximize Q, we want to maximize asymmetry in the attenuation, which is what I'm working on at the moment.
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
I'm not looking at that dirty, more a controlled dirty in the harmonics and sub-harmonics. I remember looking at the spectrum of a magnetron years ago and was appalled at the wild mixture spewing out of it. I don't think a magnetron will do unless a notch filters are used. Still working my way through it, but time for bed....
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
From what I gather a magnetron source is full of harmonics and subharmonics...one called it "dirty" which is a good visual... spectrum-wise.
...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
Oh I get it! EM Drive = Entropy Maximization Drive ! ;D
Good night!
Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.
...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894
The mapping Shawyer defines can be modelled byYes, what you state would be a possible (one of several) valid interpretation(s) of Shawyer's latest message relayed here: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894.
DF = 1 - c-d
where d = difference in diameters >=0
and c is some constant >=1; c=e for example
Entropy is keeping me out of bed....I'm too old for this (etc. etc.)
Force is dependent on the rate of change of entropy, (need to get to a thermo book tomorrow), so depends on Power. Degree of change depends on ratio of order to disorder, so Q as representing the difference between a highly monochromatic frequency distribution and the Boltzman distribution of the dissipated power as heat IN AN ASYMMETRICAL FORM DEPENDENT ON THE CAVITY SHAPE AND THE MODE !
Good Night ! (I hope ??)
Oh I get it! EM Drive = Entropy Maximization Drive ! ;D
Good night!
Well, yes, in that sense. The entropy is one more condition, like the Equivalence Principle, that the EM drive has to satisfy. The interesting point is that the entropy change can be related to a force vector. Think back to the semi-permeable membrane example in Thermodynamics 1.
The law that entropy always increases holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
......
Todd and Notsosureofit:
I found a textbook that is in Google Books that has some formulas (including calculating the Q) for (slabs and also for coaxial) dielectric inserts in a cylindrical cavity. See this:
The Google URL is huge, I hope this URL shortener works:
start at page 111 on this link http://bit.ly/1FiKoz6
Propagation, Scattering and Dissipation of Electromagnetic Waves
By A. S. Ilʹinskiĭ, A. Ya Slepyan
Series: IEEE Electromagnetic Waves Series (Book 36)
Publisher: The Institution of Engineering and Technology; First Edition edition (December 2, 1993)
ISBN-10: 0863412831
ISBN-13: 978-0863412837
Hopefully this can help you further in analyzing the thrust of a cylindrical EM Drive with a dielectric insert :)
...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Maybe first try to state what kind of nonlinear coupling effects could be at play to make a difference ? Linear system => result(wave1+wave2)=result(wave1)+result(wave2) so doing wave1+wave2 would bring nothing new, qualitatively, without a mechanism to explain result(single wave)!=0 in the first place...
An important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.
...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829894
The equation that you refer to was derived by me as an honest effort to elucidate variables, "reading tea leaves", that Shawyer had not explicitly defined (originally with @aero and others to compare numerical predictions with experimental measurements).
(http://3.bp.blogspot.com/-WXBrwiuxZRs/U92ibnqM-NI/AAAAAAAAbac/TzEbn2EqJvc/s1600/Tea-Leaves-In-Cup.gif)
You repeatedly asked me for Shaywer's Design Factor equation. Obviously, if you had been given the Design Factor equation by Shawyer, or if this expression was obvious to you from reading Shawyer's writings, there was no point in asking me for Shaywer's Design Factor (I hope and fully expect that in that case you would have made Shawyer's Design Factor available to the forum).
What was expected from Shawyer, the author of the equation, is to produce his equation: to answer "this is my equation:..." (defining the Design Factor and its variables, and not resorting to references where the variables are not explicitly defined). Instead, his response, relayed through you as a messenger, communicating behind a curtain, is an unconstructive response: Shawyer's Design Factor equation is never provided. Certainly not provided to this forum (was his equation provided instead to you in private?). Not a response one would expect in an Engineering or a Scientific journal, where the editors expect disclosure (and hence a definition) of what is being discussed (in this case what is Shawyer's Design Factor equation ?) before asserting that somebody's interpretation is wrong.
This response stands in direct contrast to the direct, constructve responses of others: Paul March (NASA) who consistently provided geometrical dimensions, defined variables, and provided honest answers to honest questions. Same for Prof. McCulloch who answered questions directly (not using messengers) both in this forum and in his blog, instead of keeping obscure what are his equations.
I look forward to your providing to this forum what is Shawyer's Design Factor equation (and then we can have a discussion of my effort to ascertain Shawyer's Design Factor, vis-à-vis Shawyer's previous papers that I had to rely on).
I also look forward to Shawyer providing the big and small diameters and the length of the truncated cones used in his experiments, so that this forum can verify the claims being made in his papers regarding the validity of his Design Factor (instead of having to rely on assessing dimensions from photographs, or resorting to parametrization of variables over a whole range, as NASA had to do to guess Shawyer's dimensions).
Hi Roger,
I have posted your email to the forum and agree working with high power anything can be dangerous. Your warning is very timely as others are buying magnetrons and screwing them to homemade cavities.
My approach is to use a programmable Rf generator (with programmable output level), connected to a max 20W Rf amp and SLOWLY increase the power applied as I vary the Rf frequency to parametrise the cavities characteristics. My cavity and Rf amplifier will be inside a tight Alum mesh 6 sided Faraday Cage (FC) to ensure no energy gets out to cause any problems. Even with the FC in place, I don't plan on getting any closer than 2 meters when it is powered on. Like you I have seen what high power and high voltage in high Q circuits can do.
As I really don't like working with bad data nor reinventing the wheel, would you please send me your Df equation in either excel or just as a corrected formula in the form below.
This would really help me understand the dynamics occurring inside a cavity as the applied Rf versus the Df derived from that frequency and cavity dimensions vary.
If I understand you correctly, no matter what the frequency nor cavity dimensions, the calculated Df should always be in the range 0 - 1 even if the small end diameter is below the cutoff frequency? In the Rodal version, if I set a really large big diameter, a really large length, small diameter to 0.299705m, the Df does = 1.0000 at 1GHz but will go above 1 if the small end diameter is less than the frequency wavelength (less than 0.299705m at 1GHz). Should that not happen?
Cl = cavity length
Cb = cavity big end diameter
Cs = cavity small end diameter
f = applied frequency
c = light speed in selected medium
Df = 2c * (Cl^2) * SQRT(4 + (c / (Cl * f))^2) * f * (Cb - Cs) /
(4 * Cb * Cs * (Cl * f)^2 + (c^2) * (Cb * Cs - (2 * Cl)^2))
...A) Since you are appreciative of my efforts in "reading the tea leaves" from Shawyer's papers :) , as a helpful, and further elucidating point, one of the critical variables that Shawyer did not explicitly define in his Design Factor equation variables in his papers is the cut-off frequency. As previously discussed in the forum (in my exchanges with @aero). The equation I provided you takes:
My intention has been made clear, to openly share everything I learn and experience during my journey to replicate the Shawyer Teeter-Totter balance beam test rig and the Flight Thruster.
When given a new equation for the EM Drive, I will write an Excel spreadsheet to allow all variables to be varied, observe the results and try to learn about how this device works. Which is what I did with your equation, and discovered there appears to be a optional frequency that gives the highest Df for a fixed set of cavity dimensions.
Further to what I learned from Shawyer, I have verified your equation does conditionally match what Shawyer claims for his Df.
Big diameter matches small diameter, Df = 0. Frequency and length variation have no effect.
Very large big diameter AND very long length, Df = 1, when small diameter matches frequency wavelength. When small diameter is larger than wavelength Df < 1, when small diameter is less than wavelength Df > 1. I note Shawyer did not mention than cavity length would have an effect on Df at this boundary condition but it does.
I'm not here to score points nor take sides. I will follow the data to where it leads me, will safely replicate the Flight Thruster and openly share that journey. I do appreciate your assistance in providing your Df equation and further thoughts.
Peace.
...A) Since you are appreciative of my efforts in "reading the tea leaves" from Shawyer's papers :) , as a helpful, and further elucidating point, one of the critical variables that Shawyer did not explicitly define in his Design Factor equation variables in his papers is the cut-off frequency. As previously discussed in the forum (in my exchanges with @aero). The equation I provided you takes:
My intention has been made clear, to openly share everything I learn and experience during my journey to replicate the Shawyer Teeter-Totter balance beam test rig and the Flight Thruster.
When given a new equation for the EM Drive, I will write an Excel spreadsheet to allow all variables to be varied, observe the results and try to learn about how this device works. Which is what I did with your equation, and discovered there appears to be a optional frequency that gives the highest Df for a fixed set of cavity dimensions.
Further to what I learned from Shawyer, I have verified your equation does conditionally match what Shawyer claims for his Df.
Big diameter matches small diameter, Df = 0. Frequency and length variation have no effect.
Very large big diameter AND very long length, Df = 1, when small diameter matches frequency wavelength. When small diameter is larger than wavelength Df < 1, when small diameter is less than wavelength Df > 1. I note Shawyer did not mention than cavity length would have an effect on Df at this boundary condition but it does.
I'm not here to score points nor take sides. I will follow the data to where it leads me, will safely replicate the Flight Thruster and openly share that journey. I do appreciate your assistance in providing your Df equation and further thoughts.
Peace.
cutOffWavelength = 2*cavityLength
This is where the cavity length comes from in the expression I provided you.
I can also provide you with an equation with any other definition for the cutOffWavelength you may prefer, for example based on the small diameter's or the big diameter's dimension. However in that case, you will be faced with two conundrums:
1) are you assuming that the longest length (suitably multiplied by the appropriate factor) is the cavityLength or the big diameter? (if both could occur then two expressions for the cutOffWavelength need to be computed and an IF statement to decide on the correct cutOffWavelength)
2) the correct cutOffWavelength for a truncated cone depends on the exact solution functions (*): spherical Bessel function and associated Legendre functions eigenvalue solutions, which would result in an equation that you would not be able to model with Excel. Based on my reading of Shawyer's papers it is apparent that Shawyer's solution is not an exact solution based on spherical Bessel functions and associated Legendre functions but is instead based on elementary functions used as an approximation over an undefined range.
B) I can also provide with a closed-form equation (that you can calculate quickly in Excel) that gives the frequency at which the Design Factor blows up and goes to infinity (instead of having to numerically approximate this frequency). Please let me know whether this would be useful to you.
(*) for a perfect cylinder, there is only one eigenvalue problem, which is readily solved in terms of the cylindrical Bessel function zeros Xmn and X'mn, and closed-form expressions can be given for the cutoff frequency in terms of given mode shapes, see http://en.wikipedia.org/wiki/Cutoff_frequency#Waveguides
As a start to understanding the microwave engineering needed to design a successful EmDrive cavity I recommend:
Microwave Engineering Passive Circuits
Peter A. Rizzi
Prentice Hall 1988
ISBN 0-13-586702-9 025
This will enable you to calculate the guide wavelengths for your proposed cavity geometry, resonant frequency and mode. You can then develop a numerical model to integrate incremental guide wavelengths to arrive at an accurate set of dimensions.
If you use a commercial finite element software package as a design aid, make sure it can cope with close to cut-off conditions. Most are hopelessly inaccurate and will even give an answer at dimensions below cut-off.
Good luck
Roger Shawyer
Hi
The derivation of my Design Factor is given in: The EmDrive - A New Satellite Propulsion Technology. This paper was presented at the “2nd Conference on Disruptive Technology in Space Activities” in Toulouse 2010, which I have attached.
As you can see the equation contains the guide wavelength terms for both ends of the cavity. The solution of these terms depends on waveguide type, dimensions, frequency and mode and can be found in any good microwave engineering text book such as the one I recommended to you.
As you will discover the solutions to the guide wavelength terms are very non-linear, which makes the accurate design of a tapered cavity particularly difficult. At SPR Ltd we have developed our own software to give a 2D high resolution numerical solution to the problem. This proprietary design software has been validated for a number of different cavities by ourselves, as well as different research groups operating under commercial agreements with SPR Ltd.
To answer your particular question about operating below cut-off, in these conditions the guide wavelength goes to infinity. As you can see from my equation, this is one reason why the value of the design factor is constrained between 0 and 1.
Hope this helps, and feel free to share this on the thread.
Best regards
Roger.
Thanks. You guys are good!...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Maybe first try to state what kind of nonlinear coupling effects could be at play to make a difference ? Linear system => result(wave1+wave2)=result(wave1)+result(wave2) so doing wave1+wave2 would bring nothing new, qualitatively, without a mechanism to explain result(single wave)!=0 in the first place...
Kudos to SeeShells !!!!! (do we need more hot and heavy weather to keep producing these great suggestions :) )
This from this paper recently brought up by Todd (hat tip to WarpTech), which confirms the validity of SeeShells suggestion:
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Attenuation in Rectangular Waveguides with Finite Conductivity Walls
Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
RADIOENGINEERING, VOL. 20, NO. 2, JUNE 2011Quote from: Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONGAn important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
...Again, Shawyer does not answer directly: he does not provide his equation for the Design Factor, and neither does he define the variables thereof.
This may be useful information:QuoteAs a start to understanding the microwave engineering needed to design a successful EmDrive cavity I recommend:
Microwave Engineering Passive Circuits
Peter A. Rizzi
Prentice Hall 1988
ISBN 0-13-586702-9 025
This will enable you to calculate the guide wavelengths for your proposed cavity geometry, resonant frequency and mode. You can then develop a numerical model to integrate incremental guide wavelengths to arrive at an accurate set of dimensions.
If you use a commercial finite element software package as a design aid, make sure it can cope with close to cut-off conditions. Most are hopelessly inaccurate and will even give an answer at dimensions below cut-off.
Good luck
Roger Shawyer
What was expected from Shawyer, the author of the equation, is to produce his equation: to answer "this is my equation:..." (defining the Design Factor and its variables, and not resorting to references where the variables are not explicitly defined).
I've got to be somewhere so I just quickly scanned the paper and it looks very good. I dig into it latter. Big Thanks Rodal!Thanks. You guys are good!...
Best Regards,
Todd
Barely able to keep pace Todd...its a good thing. maximizing asymmetry in attenuation different from absorption like the stuff I used to work with?
http://www.westernrubber.com/products/himag-microwave-absorbers/himag-cavity-resonance-absorbers/
It is getting pretty hot and heavy in here and I'm not sure I am keeping up either. Love it though.
I've been mulling around the ideas of harmonics and wondered if anyone has considered injecting 2 RF sources into the cavity,
One set and the other variable in frequency? I've been slowly working my way through this but like I said it's been slow. I welcome and inputs and thoughts.
Maybe first try to state what kind of nonlinear coupling effects could be at play to make a difference ? Linear system => result(wave1+wave2)=result(wave1)+result(wave2) so doing wave1+wave2 would bring nothing new, qualitatively, without a mechanism to explain result(single wave)!=0 in the first place...
Kudos to SeeShells !!!!! (do we need more hot and heavy weather to keep producing these great suggestions :) )
This from this paper recently brought up by Todd (hat tip to WarpTech), which confirms the validity of SeeShells suggestion:
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Attenuation in Rectangular Waveguides with Finite Conductivity Walls
Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
RADIOENGINEERING, VOL. 20, NO. 2, JUNE 2011Quote from: Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONGAn important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
All I was doing was sitting and relaxing in my hot tub (ok ok I had a cold one going too) imagining and visualizing the 2 waves in the EM container and seeing the mixing of the waves. I saw the additive factors and the losses and it looked like it might work well, but when added in the idea that to really work I needed to include what Mulletron threw at me (big kudos to him) the PTFE material you used and the properties of it to attenuate the signals I decided it was to much info and needed more time or another cold one. ;)
Zellerium
In relation to your proposed replication I remember originally mentioning a curved mirror. I was doing some microcontroller work today and now think this is not what you need for this particular experiment. The curved mirror is just a visual display device, as you will be aware it just accentuates the reflected angle of the laser, good for viewing movement but that is about all at this particular level of usage.
What would be good is an ordinary plane/flat mirror, but DONT mount it on top of the replication.
If it is on top then due to the 2 attached strings to the roof, the device will move forward BUT also due to it hanging at the bottom of a "circle" the device will move slightly upwards. This results in the mirror moving both forward and up with the effect that the lasers beam will not correctly traverse the line you want.
Place the mirror on the rear of the replication such that the laser is pointed horizontally (not vertically) at the mirror. It will strike the mirror and reflect onto the rear wall. eg mirror at 45 degree to the replication body with the mirrored side facing towards you (and outer edge back at 45) looking horizontally at the experiment. The expected line of laser traversal is horizontal.
This allows the mirror to move forwards and up as before but the upwards movement wont impact the movement/accuracy of the laser as much as before.
Ideally if you could obtain (or borrow) some light triggered timers/counters, and arrange them with equal spacing "straight" along the projected path of the beam (push the unit gently by hand initially to observe the actual path). The timers are connected to a single-trigger-unit that starts ALL the timers Simultaneously as the beam crosses the initial "start" LDR switch., then the beams path will activate each timers LDR (Light Dependent Resistor or Light Dependent Diode) to stop each timer as the beam crosses each detectors face. From there you have counts of time, difference between timer units (acceleration or constant momentum?), average velocity etc.
...Again, Shawyer does not answer directly: he does not provide his equation for the Design Factor, and neither does he define the variables thereof.
This may be useful information:QuoteAs a start to understanding the microwave engineering needed to design a successful EmDrive cavity I recommend:
Microwave Engineering Passive Circuits
Peter A. Rizzi
Prentice Hall 1988
ISBN 0-13-586702-9 025
This will enable you to calculate the guide wavelengths for your proposed cavity geometry, resonant frequency and mode. You can then develop a numerical model to integrate incremental guide wavelengths to arrive at an accurate set of dimensions.
If you use a commercial finite element software package as a design aid, make sure it can cope with close to cut-off conditions. Most are hopelessly inaccurate and will even give an answer at dimensions below cut-off.
Good luck
Roger ShawyerQuoteWhat was expected from Shawyer, the author of the equation, is to produce his equation: to answer "this is my equation:..." (defining the Design Factor and its variables, and not resorting to references where the variables are not explicitly defined).
As I pointed out in my prior message http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373671#msg1373671 the main issue is a definition for the cut-off frequency in Shawyer's design factor. Shawyer does not give you an equation for the cutoff-frequency either.
As Shawyer signs in his message: "Good Luck"
(Good luck, I suppose in ever finding out what is an explicit equation for Shawyer's Design Factor that you can program in Excel :) )
As to Shawyer's response:QuoteAt SPR Ltd we have developed our own software to give a 2D high resolution numerical solution to the problem. This proprietary design software has been validated for a number of different cavities by ourselves, as well as different research groups operating under commercial agreements with SPR Ltd.
That is not an answer to your question, which was what is the formula for the Design Factor. As a counterexample, I have a full 3D exact solution to the truncated cone for arbitrary mode shapes, in Mathematica, that is proprietary to me. That is useful to me, and of no use to anybody else (it can only be of some use to the extent that I release particular numerical solutions and images, but it is of no help to you in programming the Design Factor in Excel) ??? .
Hi everyone, this is a notification that there is a new thread here http://forum.nasaspaceflight.com/index.php?topic=37563.0 (http://forum.nasaspaceflight.com/index.php?topic=37563.0) specifically focused on an X-prize for the EM Drive. If you are interested in helping out, please come and join us.
....I sincerely applaud your altruism shown in your comment. Thank you for your generosity.
My comment:
http://forum.nasaspaceflight.com/index.php?topic=37563.msg1373714#msg1373714
Zellerium
In relation to your proposed replication I remember originally mentioning a curved mirror. I was doing some microcontroller work today and now think this is not what you need for this particular experiment. The curved mirror is just a visual display device, as you will be aware it just accentuates the reflected angle of the laser, good for viewing movement but that is about all at this particular level of usage.
What would be good is an ordinary plane/flat mirror, but DONT mount it on top of the replication.
If it is on top then due to the 2 attached strings to the roof, the device will move forward BUT also due to it hanging at the bottom of a "circle" the device will move slightly upwards. This results in the mirror moving both forward and up with the effect that the lasers beam will not correctly traverse the line you want.
Place the mirror on the rear of the replication such that the laser is pointed horizontally (not vertically) at the mirror. It will strike the mirror and reflect onto the rear wall. eg mirror at 45 degree to the replication body with the mirrored side facing towards you (and outer edge back at 45) looking horizontally at the experiment. The expected line of laser traversal is horizontal.
This allows the mirror to move forwards and up as before but the upwards movement wont impact the movement/accuracy of the laser as much as before.
Ideally if you could obtain (or borrow) some light triggered timers/counters, and arrange them with equal spacing "straight" along the projected path of the beam (push the unit gently by hand initially to observe the actual path). The timers are connected to a single-trigger-unit that starts ALL the timers Simultaneously as the beam crosses the initial "start" LDR switch., then the beams path will activate each timers LDR (Light Dependent Resistor or Light Dependent Diode) to stop each timer as the beam crosses each detectors face. From there you have counts of time, difference between timer units (acceleration or constant momentum?), average velocity etc.
....I sincerely applaud your altruism shown in your comment. Thank you for your generosity.
My comment:
http://forum.nasaspaceflight.com/index.php?topic=37563.msg1373714#msg1373714
:)
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
....What would be an acceptable displacement level for NASA EW to consistently measure with their set-up, in your view?
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
....I sincerely applaud your altruism shown in your comment. Thank you for your generosity.
My comment:
http://forum.nasaspaceflight.com/index.php?topic=37563.msg1373714#msg1373714
:)
This is me and how I work & live.
Been around too long. Have seen what greed does to people. I'm interested in solving the issue of does it work or not, with no theory wheel barrow to push. That is why I will follow the data and why I did what I did with your Df equation. It was an example of chasing the data to see what it says and where it leads me.
I'm rolling back the years and working through Shawyers Df and other supporting equation, while teaching myself what happens to microwaves when constrained in waveguides of various shapes and contours.
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
Is that displacement assuming we will get EW's thrust values?
If we use a microwave oven magnetron putting out 1 kW I hope we get much higher thrust values than EW who used only 17 ~ 50 W.
I see your concern, but without a low thrust torsion pendulum it seems near impossible to measure 20~100 micoNewtons
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
Is that displacement assuming we will get EW's thrust values?
If we use a microwave oven magnetron putting out 1 kW I hope we get much higher thrust values than EW who used only 17 ~ 50 W.
I see your concern, but without a low thrust torsion pendulum it seems near impossible to measure 20~100 micoNewtons
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
Is that displacement assuming we will get EW's thrust values?
If we use a microwave oven magnetron putting out 1 kW I hope we get much higher thrust values than EW who used only 17 ~ 50 W.
I see your concern, but without a low thrust torsion pendulum it seems near impossible to measure 20~100 micoNewtons
First it needs to be established that a displacement is produced when the EW device has RF power applied to it. Tilting and changes of the CoM due to thermal-mechanical effects could also produce the same readings. The step response of the EW TP when high voltage DC calibration pulses are applied is very different from what is observed when RF power is applied. We know the calibration pulses produce a displacement. If the step response due to applied RF looked the same then that would be more proof the TP underwent a displacement when RF power was applied. Conversely if a thermal step drive was applied to the cavity (with a DC power resistor, heating pads, or focused IR energy) and that step response had the same characteristics as the RF response there would be more evidence in the other direction.....What would be an acceptable displacement level for NASA EW to consistently measure with their set-up, in your view?
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
20 micrometers ?
Can you give us your guesstimate for an acceptable displacement threshold ? Thanks
There was a lot of discussion about the EW measurement methods on pages 62 - 70 of this thread. The actual displacement of the TP when RF power is applied is very miniscule. The illustration below shows a calibration pulse next to the distance measurement scale. The end of the TP has moved just 1 micrometer. Earlier in this thread I did a rough calculation of a laser - mirror displacement measurement setup based on this small displacement:
A problem with this experiment is the extremely small displacements that indicate a thrust. A displacement of 4 micrometers has the TP beam move through just 1.7 arcSec. of rotation. If a laser beam was reflected off the LDS moving mirror and someone was 1 km away they would see the reflected dot move just a few mm. The LDS is just as sensitive to angular changes of the mirror. An experiment of this type requires repeatable, consistent results with a signal level far above what is currently seen to provide proof of this proposed theory of its operation.
Is that displacement assuming we will get EW's thrust values?
If we use a microwave oven magnetron putting out 1 kW I hope we get much higher thrust values than EW who used only 17 ~ 50 W.
I see your concern, but without a low thrust torsion pendulum it seems near impossible to measure 20~100 micoNewtons
Cavendish pendulum.
Email received from Roger Shawyer in regard to a question to verify if Dr. Rodal's Df excel equation is correct.I obtained the following expression for the frequency at which my interpretation of Shawyer's Design Factor blows up.
Shawyer also cautions, very strongly, on the dangers of working with high power microwave systems.
frequencySingularity =cMedium* Sqrt[ (4 cavityLength^2 - bigDiameter smallDiameter)]
/(2*cavityLength*Sqrt[bigDiameter*smallDiameter] )
This can be simplified as follows:
Defining:
cutOffWavelength = 2* cavityLength (this was assumed, and built-in in my equation, other expressions for cutOffWavelength can be used alternatively)
geometricAverageDiameter = Sqrt[bigDiameter*smallDiameter]
then
frequencySingularity = cMedium* Sqrt[ (cutOffWavelength^2 - geometricAverageDiameter^2)])
/(cutOffWavelength * geometricAverageDiameter)
...Roughly correct (the diameter and the length have different factors), would you like me to give you an equation for the Design Factor in that case?
Question? What if cavity length is not the biggest cavity dimension? Should not the biggest cavity dimension be used, as I have read in the microwave waveguide theory stuff I'm researching?
...
Mmm, yes, for having "probed" that specific aspect of the pendulum system used at EagleWorks, their design is quite stiff : produces small deviation wrt forces. The forces are small and this relatively high stiffness (due to flexure bearings as pivots) doesn't help. Rambling again : the exact apparent stiffness (in µN/µm at end of arm) at EW is a poorly characterised aspect of the experiments, taking the calibration pulses as a reliable starting point gives between 9µN/µm to 40µN/µm across the various released charts, and all are in contradiction with both flexure bearings ratings and harmonic oscillation period (when visible, on underdamped plots). Appears the measures on the vertical scale of plots show much higher stiffness than it should be (too low displacement readings ?).
Anyway, there is no reason not to go with a much lower stiffness system, or no stiffness at all (no position restoring force) and record mm or cm displacements (linear or angular) as thrust accelerates the mass (as in Shawyer).
Question? What if cavity length is not the biggest cavity dimension? Should not the biggest cavity dimension be used, as I have read in the microwave waveguide theory stuff I'm researching?
And weren't there earlier murmurings that a domed end-plate should be used on the large end of the frustum instead of a flat-plate? Wouldn't you need to measure length to the center of the dome, and not the edge?
I don't dispute the need for a low thrust torsion pendulum. I'm just stating that a reflected laser beam can't provide the required resolution. The measurement sensor EW used could measure small displacements with more precision than a reflected laser beam. Microwave Oven magnetrons are hazardous and potentially lethal devices when removed from an oven. For FCC compliance and safety reasons it should be enclosed by a 6-side Faraday cage with a power interlock. Even that may not be enough to satisfy the FCC if interference is reported.
And weren't there earlier murmurings that a domed end-plate should be used on the large end of the frustum instead of a flat-plate? Wouldn't you need to measure length to the center of the dome, and not the edge?
From what I can see, Shawyer assumes the end plates are spherical and the length between them, measured relative to a line from the vertex of the cone are the same at all points.
Which means cavities with flat end plates will not achieve the calculated Df nor have a narrow resonant frequency band not have in phase end plate reflections. Is why if you desire to have a high Q cavity, curved end plates are required.
Which is what will happen with my Flight Thruster replication, which will have a variable frequency Rf generator to hunt for and find the best operational frequency.
Thank you for the response.
I guess that anecdotally lends credence to my previously-stated suspicion (from God-knows how many months back :) ) that the bottom ring on this thruster is a painted rubber gasket that acts as a footer for the domed bottom-plate it is protecting (even though the visible top plate is flat). The cracked paint on it is a dead-giveaway that it's a spongy material like rubber or silicon- perfect for a footer.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
As an added bonus, sticking with the dimensions provided by Eagleworks allows folks to use their COMSOL plots. While this cavity design might not be the optimal shape/size for max thrust, Paul March has provided potential replicators with an arsenal of very useful data on this thread applicable to those particular dimensions.
Quality useful info like this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327467#msg1327467
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
As an added bonus, sticking with the dimensions provided by Eagleworks allows folks to use their COMSOL plots. While this cavity design might not be the optimal shape/size for max thrust, Paul March has provided potential replicators with an arsenal of very useful data on this thread applicable to those particular dimensions.
Quality useful info like this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327467#msg1327467
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246
As I understand it, your cavity is same as that one? Correct?
Did you find the same 2,445GHz cavity resonance as Paul did? If not what resonance frequency did you find?
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
It seems that the phase modulation has led to an increased efficiency, so I have been considering splitting the coax signal to two different ports on the frustum for equal power signals at different phases. However this is a recent idea I have yet to research and would only be something we try after the simple setup.
Yes, great idea! Do you think it's a good idea to see if you can also provide phase shifting on the second injected signal?
I'm still working out this but the preliminary scan into the papers forwarded by Rodal it looks very good but other verification is needed as my math is rusty and my eraser is getting worn.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373661#msg1373661
This from this paper recently brought up by Todd (hat tip to WarpTech), which confirms the validity of SeeShells suggestion:
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Attenuation in Rectangular Waveguides with Finite Conductivity Walls
Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
RADIOENGINEERING, VOL. 20, NO. 2, JUNE 2011
Quote from: Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
An important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
You could modify the cavity so that it's resonant frequency can be adjusted. I don't know how easy it would be for you to do this but you could add an interior plate on the small end that can be moved. A couple of copper tubes soldered to the outside of the small end would act as guides for plastic rods connected to the interior plate. Then just move the plate a little bit at a time between tests. Eventually you will reach a resonance point. BTW how hot does the cavity get? It doesn't seem like the magnetron is overheating at all. Maybe it is operating at a low power.
Any resemblance with existing or future device(s) is purely coincidental.
Made with MEEP. Does not use the correct frequencies, material, etc. but looks cute.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829948;image)
Any resemblance with existing or future device(s) is purely coincidental.
Made with MEEP. Does not use the correct frequencies, material, etc. but looks cute.
...
Mmm, yes, for having "probed" that specific aspect of the pendulum system used at EagleWorks, their design is quite stiff : produces small deviation wrt forces. The forces are small and this relatively high stiffness (due to flexure bearings as pivots) doesn't help. Rambling again : the exact apparent stiffness (in µN/µm at end of arm) at EW is a poorly characterised aspect of the experiments, taking the calibration pulses as a reliable starting point gives between 9µN/µm to 40µN/µm across the various released charts, and all are in contradiction with both flexure bearings ratings and harmonic oscillation period (when visible, on underdamped plots). Appears the measures on the vertical scale of plots show much higher stiffness than it should be (too low displacement readings ?).
Anyway, there is no reason not to go with a much lower stiffness system, or no stiffness at all (no position restoring force) and record mm or cm displacements (linear or angular) as thrust accelerates the mass (as in Shawyer).
What measured force at NASA Eagleworks would be high enough to give confidence in the force, in your opinion?
Or there would still be a problem in your opinion with higher measured forces and higher measured displacements, as long as the stiffness remains in that range?
For example would a measured force of 200 µN and a measured displacement of 20 µm giving 10 µN/µm stiffness still lack confidence in your opinion ?
(200 µN is twice the minimum of NASA Glenn's threshold force 100 µN stipulated for measuring the EM Drive)
It appears to be different to Dr. Rodal's Df equation as there are no references, that I know of, to cavity length and focuses on the wavelengths (Lambda g1 & Lambda g2) at the 2 end plates.How's that again? There is only one wavelength in the cavity - that of the RF.
http://www.radioeng.cz/fulltexts/2011/11_02_472_478.pdf
Attenuation in Rectangular Waveguides with Finite Conductivity Walls
Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONG
RADIOENGINEERING, VOL. 20, NO. 2, JUNE 2011Quote from: Kim Ho YEAP, Choy Yoong THAM, Ghassan YASSIN, Kee Choon YEONGAn important consequence of this
work is the demonstration that the loss computed for degenerate
modes propagating simultaneously is not simply
additive. In other words, the combined loss of two co-existing
modes is higher than adding the losses of two modes
propagating independently. This can be explained by the
mode coupling effects, which is significant when the phase
constants of two propagating modes are different yet very
close.
Cavity wavelength varies depending on the cavity dimensions.Quote from: TheTravellerIt appears to be different to Dr. Rodal's Df equation as there are no references, that I know of, to cavity length and focuses on the wavelengths (Lambda g1 & Lambda g2) at the 2 end plates.How's that again? There is only one wavelength in the cavity - that of the RF.
Cavity wavelength varies depending on the cavity dimensions.Quote from: TheTravellerIt appears to be different to Dr. Rodal's Df equation as there are no references, that I know of, to cavity length and focuses on the wavelengths (Lambda g1 & Lambda g2) at the 2 end plates.How's that again? There is only one wavelength in the cavity - that of the RF.
http://www.microwaves101.com/encyclopedias/waveguide-mathematics
Cavity wavelength varies depending on the cavity dimensions.Quote from: TheTravellerIt appears to be different to Dr. Rodal's Df equation as there are no references, that I know of, to cavity length and focuses on the wavelengths (Lambda g1 & Lambda g2) at the 2 end plates.How's that again? There is only one wavelength in the cavity - that of the RF.
http://www.microwaves101.com/encyclopedias/waveguide-mathematics
Indeed. The increasing confinement of a narrowing waveguide (convergent) produces a widening wavelength and a decrease of the group velocity. Conversely, a widening waveguide (divergent) produces a narrowing wavelength and an increase of the group velocity.
Cavity wavelength varies depending on the cavity dimensions.Quote from: TheTravellerIt appears to be different to Dr. Rodal's Df equation as there are no references, that I know of, to cavity length and focuses on the wavelengths (Lambda g1 & Lambda g2) at the 2 end plates.How's that again? There is only one wavelength in the cavity - that of the RF.
http://www.microwaves101.com/encyclopedias/waveguide-mathematics
Indeed. The increasing confinement of a narrowing waveguide (convergent) produces a widening wavelength and a decrease of the group velocity. Conversely, a widening waveguide (divergent) produces a narrowing wavelength and an increase of the group velocity.
The different wavelengths at the big & small ends, due to the different diameters, are what drives Shawyers Df equation.
In fact they are what cause the end plate force differentials that drive the EM Drive.
Notice that the expression you have posted above, as defined by Shawyer blows up (goes to infinity) for the denominator going to zero. This occurs for
lambda0 = Sqrt[lambdag1*lambdag2]
or equivalently
cutOffWavelength = Sqrt[lambdag1*lambdag2]
same condition I have above in my message.
_________________________________________
Disclaimer: I don't agree with the description above (since Shawyer's uses a lot of unstated engineering approximations whose validity neither he or anyone else has proven) . I would instead write: according to Shawyer "they are what cause the end plate force differentials that drive the EM Drive."
...Writing technical papers is just as much serious business.
Will ask Shawyer how SPR calculates big and small end wavelengths Lambda g1 and g2. If he shares that info, then we will have eliminated one unknown. I dislike guessing and dislike even more to reinvent the wheel especially when it involves making actual hardware. Playing mind games or with excel is different. There we can play a bit. But building hardware is serious business. I will do what ever is necessary to reduce uncertainty about operational parameters before the cavity build starts.
...Writing technical papers is just as much serious business.
Will ask Shawyer how SPR calculates big and small end wavelengths Lambda g1 and g2. If he shares that info, then we will have eliminated one unknown. I dislike guessing and dislike even more to reinvent the wheel especially when it involves making actual hardware. Playing mind games or with excel is different. There we can play a bit. But building hardware is serious business. I will do what ever is necessary to reduce uncertainty about operational parameters before the cavity build starts.
I also dislike guessing. Readers shouldn't have to guess what an author means when the author submits a "theory paper."
If you have to ask Shawyer how he defined something in his papers is admitting that in your view his papers are insufficiently clear for you.
One thing for sure: Shawyer never stated in his papers how he defines the cut-off frequency. If the cut-off frequency is to be based on the truncated cone cut-off frequency (and not an approximation) one then has to run a a numerical solution (an eigenvalue problem) to obtain the cut-off frequency.
That's a small part of the reason why the engineering/scientific community has issues with his "theory paper". The biggest part is that he makes a large range of assumptions that are not clearly stated and are not clearly supported (certainly his reference to Cullen's paper does not support his Design Factor).
Doesn't that mean that it blows up for a cylindrical cavity? Yes. And for what other conditions does it blow up?
Lambda02 = Lambdag1 * Lambdag2 : I forget which one is the big end but it blows up whenever
Lambdag-small = Lambda02/Lambdag-big
I agree that the papers would be far more enlightening if the likelihood of such an occurrence were explained. And so would this forum for that matter.
First people are saying that the big end has a smaller lambda than the small end, and then other people say the opposite. Can't be bothered assembling the quotes.If Shawyer's papers would clearly define the variables, you wouldn't need to ask, would you ;) :
In any case, if lambda1 < lambda2 (whichever ends they represent), I am still asking if the following is true
lambda1 <= lambda0 <= lambda2 ???
....
As defined in the attachment dominant circular waveguide cutoff wavelength is 1.7 x diameter....
1.7 x diameter...
Yes of course, but what diameter? A cylinder has only one diameter. It has constant diameter.
Shawyer's EM Drive is not a cylinder with constant diameter. Shawyer's EM Drive is a truncated cone.
A truncated cone has a variable diameter. The diameters are different at each end.
Shawyer's reference (Cullen) does not deal with truncated cones.
What diameter ?
Look at what I derived in http://forum.nasaspaceflight.com/index.php?topic=36313.msg1373898#msg1373898:
...choosing the cutOffWavelength to be TE110,
Look at where the factor of 1.7 comes from: it is Pi divided by X'11
cOW = gmD *(Pi/1.84118378134065)
= gmD *1.7062895542683174
1.7 times the Geometric Mean of the Diameters
cOW = cutOffWavelength
gmD = Sqrt[bD * sD]
bD = big end diameter (m)
sD= small end diameter (m)
I'm only asking so as to help out with the maths. It doesn't mean I believe a word about its physicality.
For example: if the expression I'm trying to get verified is true, then you can get your blow-up condition. Other conditional relations produce different results (x0 < x1 < x2 or x1 < x2 < x0: x=lambda).
Then there's also the case that it blows up exactly when the numerator is also zero. As you know, 0/0 is an indeterminate quantity.
I find a nicer way to write Shawyer's Df is like this (again using x=lambda)
Df = x0*(x2 - x1) / (x1*x2 - x02)
You'll notice that Df=0 when x1 or x2 -> infinity (proof available on request but it's dead simple)
Someone said that Df varied between 0 and 1, and should =1 when x1 or x2 -> inf. It doesn't.
And obviously Df=0 when x1 = x2. So it can be zero for two separate reasons.
Doh!
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you that the lambda in free space should be smaller than in the waveguide in principle.
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you in principle. I have to double check where he puts the cutoff wavelength...
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you in principle. I have to double check where he puts the cutoff wavelength...
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
All wavelengths inside the conic cavity are bigger than outside and the resultant group velocities are less than the velocity outside.
The guide wavelength and resultant group velocity constantly varies, driven by the constantly varying diameter of the conic section the wave is passing through.
Also the edges of the wave fronts are at right angles to the cone sides due to being spherical wave fronts as if they originated from and are returning to the vertex of the cone.
If however the conic cavity end plates are flat and not spherically matching the spherical wave fronts bouncing off them, well you may be pushing s##t up hill before things are working well inside the cavity.
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you in principle. I have to double check where he puts the cutoff wavelength...
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
All wavelengths inside the conic cavity are bigger than outside and the resultant group velocities are less than the velocity outside.
The guide wavelength and resultant group velocity constantly varies, driven by the constantly varying diameter of the conic section the wave is passing through.
Also the edges of the wave fronts are at right angles to the cone sides due to being spherical wave fronts as if they originated from and are returning to the vertex of the cone.
If however the conic cavity end plates are flat and not spherically matching the spherical wave fronts bouncing off them, well you may be pushing s##t up hill before things are working well inside the cavity.
So Shawyer does not have a cut-off wavelength appearing anywhere on his Design Factor ?
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you in principle. I have to double check where he puts the cutoff wavelength...
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
All wavelengths inside the conic cavity are bigger than outside and the resultant group velocities are less than the velocity outside.
The guide wavelength and resultant group velocity constantly varies, driven by the constantly varying diameter of the conic section the wave is passing through.
Also the edges of the wave fronts are at right angles to the cone sides due to being spherical wave fronts as if they originated from and are returning to the vertex of the cone.
If however the conic cavity end plates are flat and not spherically matching the spherical wave fronts bouncing off them, well you may be pushing s##t up hill before things are working well inside the cavity.
So Shawyer does not have a cut-off wavelength appearing anywhere on his Design Factor ?
He uses what the industry uses. Guide wavelength as in the attached. It is related to cutoff wavelength as per the attached equation
Df = 0 when lambda1 = lambda2
Df = 1 when min(lambda1, lambda2) = lambda0 (free space condition)
So it looks like the right Df
Rodal, you seem confused. Lambda0 is the free space wavelength = c/f. Equation (5) tells you the rest.
You missed my post above. In order for the group velocity in the waveguide to never exceed c (and it never does!) it follows from eqn(5) that all lambda's in the waveguide are greater than the lambda in free space.I agree with you in principle. I have to double check where he puts the cutoff wavelength...
Therefore 1 - (lambda02/(lambda1*lambda2)) is always positive definite.
Therefore blow-up is impossible
All wavelengths inside the conic cavity are bigger than outside and the resultant group velocities are less than the velocity outside.
The guide wavelength and resultant group velocity constantly varies, driven by the constantly varying diameter of the conic section the wave is passing through.
Also the edges of the wave fronts are at right angles to the cone sides due to being spherical wave fronts as if they originated from and are returning to the vertex of the cone.
If however the conic cavity end plates are flat and not spherically matching the spherical wave fronts bouncing off them, well you may be pushing s##t up hill before things are working well inside the cavity.
So Shawyer does not have a cut-off wavelength appearing anywhere on his Design Factor ?
He uses what the industry uses. Guide wavelength as in the attached. It is related to cutoff wavelength as per the attached equation
No, he doesn't use the standard definition because according to that formula there is only one waveguide wavelength and he is defining two of them.
Same question that deltaMass was asking
How does Shawyer define lambdag 1 and lambdag 2 ?
He does define lambdag1 not equal to lambdag2, so they are different, we know that
what is the difference?
In the formula you show the only things that appear are the free space wavelength and the cut off wavelength
But there is only one free space wavelength
There is only one cutoff wavelength
SO WHAT IS THE DIFFERENCE between lambdag1 and lambdag2
....
The cutoff wavelength is defined for EACH end, based on it's diameter * 1.71. See attachment 2.
Lambda1 = guide wavelength equation from attachment 1 below using big end cutoff wavelength.
Lambda2 = guide wavelength equation from attachment 1 below using small end cutoff wavelength.
The Traveller: I know, and what I said doesn't contradict you, except that cut-off isn't necessary.
....
The cutoff wavelength is defined for EACH end, based on it's diameter * 1.71. See attachment 2.
Lambda1 = guide wavelength equation from attachment 1 below using big end cutoff wavelength.
Lambda2 = guide wavelength equation from attachment 1 below using small end cutoff wavelength.
OK
Thanks for the answer
Very clear answer
That's NOT what deltaMass had written (there is no N=1,2,3,4, in equation 5)
That's exactly the same factor of 1.7 I derived, based on TE110
Now I'm going to sleep.
The Traveller: I know, and what I said doesn't contradict you, except that cut-off isn't necessary.
Shawyer always says the small end cutoff wavelength should be just above small end cutoff for best thrust generation. The higher the Df, the higher the resultant thrust from T = 2 Df Po Q / c
So the small end operating at just above cutoff is important to achieve a Df close to 1.
The Traveller: I know, and what I said doesn't contradict you, except that cut-off isn't necessary.
Shawyer always says the small end cutoff wavelength should be just above small end cutoff for best thrust generation. The higher the Df, the higher the resultant thrust from T = 2 Df Po Q / c
So the small end operating at just above cutoff is important to achieve a Df close to 1.
Not if you take that Df at face value, no. Let's do some high school algebra. I use x to mean lambda, and I can't be bothered using suffices throughout.
We start with the relation we know to be true: x2 >= x1 >= x0.
We now quantify this with these definitions:
x2 := a*x1 (a >= 1)
x1 := b*x0 (b >= 1)
The original Df expression:
Df = x0*(x2 - x1) / (x1*x2 - x02)
becomes, using the above definitions:
Df = b*(a - 1) / (a*b2 - 1)
What's Df when x1 = x0?
This is tantamount to setting b=1. Doing that, we get
Df = (a-1) / (a-1) = 1. QED.
i.e. it doesn't matter what the value of 'a' might be; i.e. it doesn't matter about cutoff.
I ought to mention that Shawyer does not specify how to compute vg or lambdag. What he does do is specify the functional relation between them - i.e. v(lambda) or lambda(v) - and that's all.
Anyone know how to compute vg without using lambdag?
Anyone know how to compute lambdag without using vg?
Wrong. (You need AND)Thanks! - you are quite correct. But no need for Mathematica.
Any resemblance with existing or future device(s) is purely coincidental.
Made with MEEP. Does not use the correct frequencies, material, etc. but looks cute.
Is that a 2-Dimensional model with MEEP?
Maxwell's equations in a flat 2-D surface?
modeling the truncated cone as a FLAT trapezium ?
Is the magnetic field (for TM modes) a point scalar (only able to have + or - sign but the direction is always perpendicular to the surface) instead of being a vector in the azimuthal (circumferential) direction ?
What are we seeing out of the EM Drive? evanescent wave field?
If the answers are yes, do you have enough memory to run a 3D model instead?
Thanks
Any resemblance with existing or future device(s) is purely coincidental.
Made with MEEP. Does not use the correct frequencies, material, etc. but looks cute.
You might want to increase your skin thickness or Meep resolution. Looks kind of like a Gaussian source with some of the shorter wavelengths bouncing around and longer wavelengths stepping over the boundary (numerically)?
Yes, I noticed that and tried to improve the resolution with not much success so far. I'll keep playing.
If you are using perfect metal for the skin, then the thickness won't change the result but will help to avoid the model numerically spanning the skin. If you are modelling copper in the GHz range, please tell me about your model as I have struggled for 6 months trying to find a Drude model for copper at 2 GHz.
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
Published 12 May 2015
This represents the current state of the art.
http://iopscience.iop.org/0953-8984/27/21/210301/article
http://iopscience.iop.org/0953-8984/27/21 (TOC)
I'm pretty excited about what could come out of applying these materials too...maybe a way forward:
http://www.lap.physik.uni-erlangen.de/lap/?page=research_krstic_chiral&language=en
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
another good publication.Published 12 May 2015
This represents the current state of the art.
http://iopscience.iop.org/0953-8984/27/21/210301/article
http://iopscience.iop.org/0953-8984/27/21 (TOC)
I'm pretty excited about what could come out of applying these materials too...maybe a way forward:
http://www.lap.physik.uni-erlangen.de/lap/?page=research_krstic_chiral&language=en
Excited? I'm more than excited. I think I've reached my limits of current understanding and applying these effects to the EM device. I need more time to read and digest because every article seems to have a little something that fits in the overall scheme of why. Mullutron I think you have a tiger by the tale here.
Like this one.
Transfer of linear momentum from the quantum vacuum to a magnetochiral molecule
M Donaire1, B A van Tiggelen2 and G L J A Rikken3
Show affiliations
M Donaire et al 2015 J. Phys.: Condens. Matter 27 214002. doi:10.1088/0953-8984/27/21/214002
Received 14 April 2014, accepted for publication 2 July 2014. Published 12 May 2015.
© 2015 IOP Publishing Ltd
Abstract
In a recent publication [1] we have shown using a QED approach that, in the presence of a magnetic field, the quantum vacuum coupled to a chiral molecule provides a kinetic momentum directed along the magnetic field. Here we explain the physical mechanisms which operate in the transfer of momentum from the vacuum to the molecule. We show that the variation of the molecular kinetic energy originates from the magnetic energy associated with the vacuum correction to the magnetization of the molecule. We carry out a semiclassical calculation of the vacuum momentum and compare the result with the QED calculation.
... I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record....I think you have done an outstanding job in discovering what Shawyer may have meant.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
...
Of course, EW and @RODAL's calculations show the big end hotter.
...
...
Of course, EW and @RODAL's calculations show the big end hotter.
...
Great post !!!
My calculations only assume Maxwell's linear equations. EW has a dielectric inside and they measured very small forces and very low temperatures.
Keep thinking and challenging all assumptions:
Because the Chinese (Prof. Yang's) measurements with embedded thermocouples show the OPPOSITE of NASA Eagleworks, in agreement with your expectation: the small end is much hotter
Prof. Juan Yang's reported temperature vs. time measurements with embedded thermocouples throughout their EM Drive cavity (without a polymer dielectric insert) under atmospheric conditions, that, curiously, show the highest temperature at the center of the small base (trace #1), followed, at a significantly lower temperature by the temperature at the periphery of the big base (trace #5).
Take a look at the temperatures measured by the thermocouple Trace #1
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=622845;image)
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=655009;image)
@Rodal: You say that you get a blow-up with your Df formula, and yetYou are thinking correctly, as a physical situation, as if lambda0 and lambdag1,2 are wavelengths occurring at a particular point in time and space.
a) you agree that both lambdag1,2 are greater than lambda0 (because vg < c)
b) you agree that, this being the case, it's mathematically impossible to get blow-up (denominator zero)
Clarify please?
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
...You are correct: Shawyer uses a number of references for open waveguides instead of closed cavities. For example, his main reference is Cullen's Ph.D. thesis published in the early '50s. When reading Cullen's paper I was surprised to find out that Cullen had used an OPEN waveguide (it had a transparent glass at one end, transparent to microwaves on purpose) to experimentally measure the pressure on the other end (where waves are reflected) of an open cylindrical waveguide. Not a truncated cone closed cavity.
You're guided wavelength equation is wrong, because this is for a rectangular wave guide (i.e., not even a rectangular cavity)
...
...Yes, see this: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369861#msg1369861
You're guided wavelength equation is wrong, because this is for a rectangular wave guide (i.e., not even a rectangular cavity)
...
I've been trying to wrap my brain around why a difference in phase results in a better thrust. Also, why couldn't EW obtain a thrust without a dielectric?I'm digging through this paper right now and it seems to offer an answer to your question. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
I think we can all agree that in order for a net thrust, the momentum delivered to the larger end plate is smaller than that delivered to the smaller end plate. So where did the momentum go?
Can momentum be delivered and removed from an orbiting electron?
Take a simple two dimensional case with two atoms, one on the small end, one on the large end, each with their own electron orbiting at a the same angular frequency. If a force is applied to both of them, one in the direction of revolution and the other opposite, one of the forces would slow down the electron and the other would speed it up. The sped up electron requires a larger force to keep it tied to the nucleus and we have a net thrust.
Perhaps this could help explain a couple things:
The dielectric is composed of different elements, thus the electrons are orbiting at a different angular velocity. Using a constant frequency with different elements gives a certain degree of difference in the phase at which momentum is delivered to the electrons.
Shawyer observed more losses with a dielectric because a magnetron outputs a signal at many phases and somehow 'matches' the orbital tendency of the electrons.
I imagine the magnetic component of the wave could be contributing to an alignment of electrons which could amplify this miniscule effect.
Any thoughts?
... Right now everything you are doing is wrong because you don't understand the physics. ...
Also, to the guy operating the microwave magnetron outside of the microwave: STOP
At best you are violating the laws of your local government's regulatory committee for the electromagnetic spectrum. At worst you will damage your body. At this frequency, the damage is somewhat insidious. Due to low water content of your skin, you don't feel the heat, but internal nerve endings can be damaged so that chronic phantom pain can appear. Sometimes days after exposure. Please STOP otherwise you will inevitably be reported to your government.
...I find it disheartening how much smaller is the effect explored in this "Tar Baby in the Brier Patch" paper and van Tiggelen's other papers, compared to what is claimed by the EM Drive researchers (particularly what is claimed by Shawyer and Prof. Yang regarding measured forces), and the fact that Shawyer and Prof. Yang do not use any dielectric polymer insert in their tests.
I'm digging through this paper right now and it seems to offer an answer to your question. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
http://arxiv.org/pdf/1011.4376.pdf
I had a look through the paper and am surprised the effect exists at all. Can someone explain where the opposite momentum goes?I'm surprised that you are not asking: if indeed one can obtain this momentum (however little teeny tiny) by interacting with the QV, does that mean that one can obtain energy (however little teeny tiny) from the QV, and therefore there is a paradox ? ;)
I had a look through the paper and am surprised the effect exists at all. Can someone explain where the opposite momentum goes?
I understand the concern, I really do and it worries me too. There might be more than one way. I'm looking for the connection(s) and commonality in all....I find it disheartening how much smaller is the effect explored in this "Tar Baby in the Brier Patch" paper and van Tiggelen's other papers, compared to what is claimed by the EM Drive researchers (particularly what is claimed by Shawyer and Prof. Yang regarding measured forces), and the fact that Shawyer and Prof. Yang do not use any dielectric polymer insert in their tests.
I can feel your pain, understand your concern and yes it concerns me too.
I'm digging through this paper right now and it seems to offer an answer. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
http://arxiv.org/pdf/1011.4376.pdf
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
I've built and tested many microwave cavities over many years.
You're guided wavelength equation is wrong, because this is for a rectangular wave guide (i.e., not even a rectangular cavity)
You need to derive mode of frequency yourself (unless there is a paper somewhere) for a circular tapered cavity. There is no other way around it. I would start with Balanis - Advanced Engineering Electromagnetics as he derives a few examples for other topologies. Right now everything you are doing is wrong because you don't understand the physics. I would study that book from front to cover if I were you.
... Right now everything you are doing is wrong because you don't understand the physics. ...
Given that he is at least one person among billions on this planet who is attempting a replication of a mystifying device, much of what he is doing is right.Also, to the guy operating the microwave magnetron outside of the microwave: STOP
At best you are violating the laws of your local government's regulatory committee for the electromagnetic spectrum. At worst you will damage your body. At this frequency, the damage is somewhat insidious. Due to low water content of your skin, you don't feel the heat, but internal nerve endings can be damaged so that chronic phantom pain can appear. Sometimes days after exposure. Please STOP otherwise you will inevitably be reported to your government.
While I agree with your safety suggestions, I think your tone and delivery are a bit over the top. Microwaves are easily contained.
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
I've built and tested many microwave cavities over many years.
You're guided wavelength equation is wrong, because this is for a rectangular wave guide (i.e., not even a rectangular cavity)
You need to derive mode of frequency yourself (unless there is a paper somewhere) for a circular tapered cavity. There is no other way around it. I would start with Balanis - Advanced Engineering Electromagnetics as he derives a few examples for other topologies. Right now everything you are doing is wrong because you don't understand the physics. I would study that book from front to cover if I were you.
The Guide Wavelength equation uses a circular cutoff wavelength as it's basis. That cutoff wavelength used is for the end conditions, just before reflection. It only focuses on that happens at each end.
A rectangular waveguide will have a different cutoff wavelength and hence a different Guide Wavelength.
As an ex ham, I see this as 2 semi connected resonate elements of an antenna. Each element has it's own unique operational characteristics as do each of the ends.
The length between the 2 ends is tuned to be at resonance of some sub, prime or harmonic of the Rf driving frequency as Shawyer says in the attachment.
My EM Drive design calculator says that for the Flight Thruster dimensions worked out on this thread, the length is very close to resonance at 2x the 3.85GHz wavelength and likewise the Df = 1 condition also occurs at close to the Rf driving frequency. I don't think this is a random event.
While I respect you may not agree with Shawyers or this analysis, I suggest that the Df =1 and length resonance results supporting operation at 3.85GHZ has added some degree of validity to the equation and calc process. At least for me.
I understand the concern, I really do and it worries me too. There might be more than one way. I'm looking for the connection(s) and commonality in all....I find it disheartening how much smaller is the effect explored in this "Tar Baby in the Brier Patch" paper and van Tiggelen's other papers, compared to what is claimed by the EM Drive researchers (particularly what is claimed by Shawyer and Prof. Yang regarding measured forces), and the fact that Shawyer and Prof. Yang do not use any dielectric polymer insert in their tests.
I can feel your pain, understand your concern and yes it concerns me too.
I'm digging through this paper right now and it seems to offer an answer. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
http://arxiv.org/pdf/1011.4376.pdf
It's hard to glean information from the other tests, I see what's going on right now in setting the cavity sizes and selecting correct harmonics (good detective work BTW) from the lack of information. Your tests were the only one where I feel confident that you used and reported a Dielectric Polymer with a solid yea/nay, it works, it doesn't. On a side note in my business of building Semiconductor machines (sold it and retired in 08 btw) I received sheet metals (copper included) with very thin coatings of plastic sheeting that needed to be pealed off, did I get it all before using, did some adhere, bonding to the surface affecting the tests? I'm not sure as that info isn't there.
This paper looks like it may offer out a way to the issues of violation of CoE and CoM which is a severe no no. As to the difference between the tests we simply have to do some more detective work. I think the answers are there.
I've been trying to wrap my brain around why a difference in phase results in a better thrust. Also, why couldn't EW obtain a thrust without a dielectric?I'm digging through this paper right now and it seems to offer an answer to your question. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
I think we can all agree that in order for a net thrust, the momentum delivered to the larger end plate is smaller than that delivered to the smaller end plate. So where did the momentum go?
Can momentum be delivered and removed from an orbiting electron?
Take a simple two dimensional case with two atoms, one on the small end, one on the large end, each with their own electron orbiting at a the same angular frequency. If a force is applied to both of them, one in the direction of revolution and the other opposite, one of the forces would slow down the electron and the other would speed it up. The sped up electron requires a larger force to keep it tied to the nucleus and we have a net thrust.
Perhaps this could help explain a couple things:
The dielectric is composed of different elements, thus the electrons are orbiting at a different angular velocity. Using a constant frequency with different elements gives a certain degree of difference in the phase at which momentum is delivered to the electrons.
Shawyer observed more losses with a dielectric because a magnetron outputs a signal at many phases and somehow 'matches' the orbital tendency of the electrons.
I imagine the magnetic component of the wave could be contributing to an alignment of electrons which could amplify this miniscule effect.
Any thoughts?
http://arxiv.org/pdf/1011.4376.pdf
We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
... Right now everything you are doing is wrong because you don't understand the physics. ...
Given that he is at least one person among billions on this planet who is attempting a replication of a mystifying device, much of what he is doing is right.Also, to the guy operating the microwave magnetron outside of the microwave: STOP
At best you are violating the laws of your local government's regulatory committee for the electromagnetic spectrum. At worst you will damage your body. At this frequency, the damage is somewhat insidious. Due to low water content of your skin, you don't feel the heat, but internal nerve endings can be damaged so that chronic phantom pain can appear. Sometimes days after exposure. Please STOP otherwise you will inevitably be reported to your government.
While I agree with your safety suggestions, I think your tone and delivery are a bit over the top. Microwaves are easily contained.
If microwaves were easily contained there wouldn't be a multi billion dollar industry for the testing and consultation of microwave containment.
Seriously, its a big problem. I was amused by this before but when people start using high powered dirty sources to corrupt bands of the spectrum I get angry. I've processed too many Earth Observing land surface experiments that were corrupted and unusable outside of Canada and the US due to unlicensed device usage. It is perplexing that a forum dedicated to spaceflight would encourage such bad form.
...Don't forget about the nonreciprocity of Nitrogen papers.Isn't the magnitude of this effect (nonreciprocity of Nitrogen papers), regarding a thrust force even smaller than the magnitude for the chiral polymer ?
http://arxiv.org/abs/1101.0712
http://arxiv.org/abs/1101.1174
http://www2.cnrs.fr/en/1859.htm
http://phys.org/news/2011-05-when-the-speed-of-light.html
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1330846#msg1330846
Imagine the implications of having the speed of light depend on its direction in a medium....
... Right now everything you are doing is wrong because you don't understand the physics. ...
Given that he is at least one person among billions on this planet who is attempting a replication of a mystifying device, much of what he is doing is right.Also, to the guy operating the microwave magnetron outside of the microwave: STOP
At best you are violating the laws of your local government's regulatory committee for the electromagnetic spectrum. At worst you will damage your body. At this frequency, the damage is somewhat insidious. Due to low water content of your skin, you don't feel the heat, but internal nerve endings can be damaged so that chronic phantom pain can appear. Sometimes days after exposure. Please STOP otherwise you will inevitably be reported to your government.
While I agree with your safety suggestions, I think your tone and delivery are a bit over the top. Microwaves are easily contained.
If microwaves were easily contained there wouldn't be a multi billion dollar industry for the testing and consultation of microwave containment.
Seriously, its a big problem. I was amused by this before but when people start using high powered dirty sources to corrupt bands of the spectrum I get angry. I've processed too many Earth Observing land surface experiments that were corrupted and unusable outside of Canada and the US due to unlicensed device usage. It is perplexing that a forum dedicated to spaceflight would encourage such bad form.
Like the 17 years it took Parkes to find out it was a microwave oven causing the perytons they were getting in the radio telescope? http://abcnews.go.com/Technology/microwave-oven-stumped-astronomers-17-years/story?id=30822415
And I don't see how you will get repeatablity with a nasty old maggie, unless this is a brute force effect. A Klystron based source would be a better option IMHO.
The length of the waveguide from the magnetron is chosen to reduce back reflected power from the cavity to protect itself. The waveguide feeding from the magnetron into the cavity is a separate entity. So its hard to really understand what you are talking about. Cut off frequency and mode shapes for different cavity shapes have been described long ago and proven again and again, so I'm not sure what this has to do with Sawyer and his (strange) calculations.
I understand the concern, I really do and it worries me too. There might be more than one way. I'm looking for the connection(s) and commonality in all....I find it disheartening how much smaller is the effect explored in this "Tar Baby in the Brier Patch" paper and van Tiggelen's other papers, compared to what is claimed by the EM Drive researchers (particularly what is claimed by Shawyer and Prof. Yang regarding measured forces), and the fact that Shawyer and Prof. Yang do not use any dielectric polymer insert in their tests.
I can feel your pain, understand your concern and yes it concerns me too.
I'm digging through this paper right now and it seems to offer an answer. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
http://arxiv.org/pdf/1011.4376.pdf
It's hard to glean information from the other tests, I see what's going on right now in setting the cavity sizes and selecting correct harmonics (good detective work BTW) from the lack of information. Your tests were the only one where I feel confident that you used and reported a Dielectric Polymer with a solid yea/nay, it works, it doesn't. On a side note in my business of building Semiconductor machines (sold it and retired in 08 btw) I received sheet metals (copper included) with very thin coatings of plastic sheeting that needed to be pealed off, did I get it all before using, did some adhere, bonding to the surface affecting the tests? I'm not sure as that info isn't there.
This paper looks like it may offer out a way to the issues of violation of CoE and CoM which is a severe no no. As to the difference between the tests we simply have to do some more detective work. I think the answers are there.
Don't forget about the nonreciprocity of Nitrogen papers.
http://arxiv.org/abs/1101.0712
http://arxiv.org/abs/1101.1174
http://www2.cnrs.fr/en/1859.htm
http://phys.org/news/2011-05-when-the-speed-of-light.html
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1330846#msg1330846
Imagine the implications of having the speed of light depend on its direction in a medium.QuoteI've been trying to wrap my brain around why a difference in phase results in a better thrust. Also, why couldn't EW obtain a thrust without a dielectric?I'm digging through this paper right now and it seems to offer an answer to your question. I'll re-read it several times, as it's looking to be the Tar Baby in the Brier Patch for me.
I think we can all agree that in order for a net thrust, the momentum delivered to the larger end plate is smaller than that delivered to the smaller end plate. So where did the momentum go?
Can momentum be delivered and removed from an orbiting electron?
Take a simple two dimensional case with two atoms, one on the small end, one on the large end, each with their own electron orbiting at a the same angular frequency. If a force is applied to both of them, one in the direction of revolution and the other opposite, one of the forces would slow down the electron and the other would speed it up. The sped up electron requires a larger force to keep it tied to the nucleus and we have a net thrust.
Perhaps this could help explain a couple things:
The dielectric is composed of different elements, thus the electrons are orbiting at a different angular velocity. Using a constant frequency with different elements gives a certain degree of difference in the phase at which momentum is delivered to the electrons.
Shawyer observed more losses with a dielectric because a magnetron outputs a signal at many phases and somehow 'matches' the orbital tendency of the electrons.
I imagine the magnetic component of the wave could be contributing to an alignment of electrons which could amplify this miniscule effect.
Any thoughts?
http://arxiv.org/pdf/1011.4376.pdf
Exact words from Eagleworks about obtaining thrust without a dielectric:QuoteWe performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf
If microwaves were easily contained there wouldn't be a multi billion dollar industry for the testing and consultation of microwave containment.
Seriously, its a big problem. I was amused by this before but when people start using high powered dirty sources to corrupt bands of the spectrum I get angry. I've processed too many Earth Observing land surface experiments that were corrupted and unusable outside of Canada and the US due to unlicensed device usage. It is perplexing that a forum dedicated to spaceflight would encourage such bad form.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
@Rodal: You say that you get a blow-up with your Df formula, and yet
a) you agree that both lambdag1,2 are greater than lambda0 (because vg < c)
b) you agree that, this being the case, it's mathematically impossible to get blow-up (denominator zero)
Clarify please?
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
This is a picture for the FLIGHT THRUSTER case
bD=0.2440 m ;sD=0.1450 m ;cMedium=299705000 m/s (Air)
which has a cut-off frequency associated with the small diameter of 1.21136 GHz
Notice that there is a singularity at 1.21136 GHz such that Shawyer's Design Factor doesn't have a Real value for frequencies below it. Also notice the rise and steepening of the Design Factor curve as the cut-off frequency is approached.
QUESTION: If Shawyer thinks that his Design Factor steepening behavior near the cut-off frequency associated with the small diameter is correct, why didn't he test his Flight Thruster at a lower frequency, closer to 1.2 GHz instead of the higher frequency he chose of 3.782 GHz? Doesn't Shawyer want to maximize thrust force ?
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
This is a picture for the FLIGHT THRUSTER case
bD=0.2440 m ;sD=0.1450 m ;cMedium=299705000 m/s (Air)
which has a cut-off frequency associated with the small diameter of 1.21136 GHz
Notice that there is a singularity at 1.21136 GHz such that Shawyer's Design Factor doesn't have a Real value for frequencies below it. Also notice the rise and steepening of the Design Factor curve as the cut-off frequency is approached.
QUESTION: If Shawyer thinks that his Design Factor steepening behavior near the cut-off frequency associated with the small diameter is correct, why didn't he test his Flight Thruster at a lower frequency, closer to 1.2 GHz instead of the higher frequency he chose of 3.782 GHz? Doesn't Shawyer want to maximize thrust force ?
Shawyer has said Df = 1 is the max value to consider in the real world. Which I have done. Try these dimensions and frequency and see what Df you get?
Note both the DF = 1 frequency and cavity length resonance frequency are the same and that the cavity dimension are close to those workout on this forum. So the guys who did that work were close.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830141;image)
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
This is a picture for the FLIGHT THRUSTER case
bD=0.2440 m ;sD=0.1450 m ;cMedium=299705000 m/s (Air)
which has a cut-off frequency associated with the small diameter of 1.21136 GHz
Notice that there is a singularity at 1.21136 GHz such that Shawyer's Design Factor doesn't have a Real value for frequencies below it. Also notice the rise and steepening of the Design Factor curve as the cut-off frequency is approached.
QUESTION: If Shawyer thinks that his Design Factor steepening behavior near the cut-off frequency associated with the small diameter is correct, why didn't he test his Flight Thruster at a lower frequency, closer to 1.2 GHz instead of the higher frequency he chose of 3.782 GHz? Doesn't Shawyer want to maximize thrust force ?
Shawyer has said Df = 1 is the max value to consider in the real world. Which I have done. Try these dimensions and frequency and see what Df you get?
Note both the DF = 1 frequency and cavity length resonance frequency are the same and that the cavity dimension are close to those workout on this forum. So the guys who did that work were close.
Sorry, the dimensions I see in that spreadsheet are the same dimensions I see in your prior post:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374106#msg1374106
bD=0.2440 m ;sD=0.1450 m ;
which give a Design Factor below 0.5
Could you please send the dimensions in another post and double check them ? Thanks
...
Note the frequency is NOT 3.85GHz. There are THREE factors in the Df equation, Small End diameter, Big End diameter and FREQUENCY.
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
Lucky that Nasa hasn't stopped the experiments. It would be a more than a little upsetting if they stoped the progress Eagle works has made.NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
Yes! I have done a letter and also urge you to do so, oh also beg your friends and relatives too.Lucky that Nasa hasn't stopped the experiments. It would be a more than a little upsetting if they stoped the progress Eagle works has made.NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...
They are downplaying it. At NASA Glenn's site they are directing interested people to an ex-employee (Millis) and not saying anything about Eagleworks work... :(
Everybody interested should write to their congressmen
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
Which news, can you elaborate?
NASA reporting that there is no warpdrive spacecraft and downplaying Eagleworks:
See:
http://news.yahoo.com/no-warp-drive-nasa-downplays-impossible-em-drive-193528141.html
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
Yes, but am I correct as seeing the a and b terms in the frustum case as generating Doppler-shifted sidebands ? (the alternative being non-linear terms)
This would suggest that the EW interferometer should replace the "pillbox" cavity with a frustrum and analyze by including a Fabry-Perot into the system? (might need a mode-locked laser as well.)
Lucky that Nasa hasn't stopped the experiments. It would be a more than a little upsetting if they stoped the progress Eagle works has made.NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...
They are downplaying it. At NASA Glenn's site they are directing interested people to an ex-employee (Millis) and not saying anything about Eagleworks work... :(
Everybody interested should write to their congressmen
...
Note the frequency is NOT 3.85GHz. There are THREE factors in the Df equation, Small End diameter, Big End diameter and FREQUENCY.
Look at this image: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830138
for those dimensions and look at the horizontal axis for frequency. At that frequency the Design Factor is still below 0.5
Shawyer's design factor is practically unaffected by frequency except near the cut-off frequency for the small diameter.
Shawyer's Design Factor is highest at lowest frequency (near cut-off) and it decreases with frequency
See my equations: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110
...
Note the frequency is NOT 3.85GHz. There are THREE factors in the Df equation, Small End diameter, Big End diameter and FREQUENCY.
Look at this image: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830138
for those dimensions and look at the horizontal axis for frequency. At that frequency the Design Factor is still below 0.5
Shawyer's design factor is practically unaffected by frequency except near the cut-off frequency for the small diameter.
Shawyer's Design Factor is highest at lowest frequency (near cut-off) and it decreases with frequency
See my equations: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110
Houston we have a problem.
Working it.
Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.
Interesting interactions.
Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.
The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.
Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.
Shields up. Rock throwing time.
Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.
Interesting interactions.
Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.
The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.
Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.
Shields up. Rock throwing time.
Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.
Interesting interactions.
Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.
The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.
Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.
Shields up. Rock throwing time.
Congratulations on fixing it.
I see some differences with my plot using Mathematica. One minor, immaterial difference is that Excel artificially brings the value of the Design Factor down to zero for frequencies below the cutoff frequency and it artificially draws a vertical line at the cutoff frequency. Mathematica does not, because the Design Factor does not go down to zero below the cut-off frequency, actually its value becomes a Complex number below the cutoff frequency (since it involves the Square Root of a negative number), and the vertical line shouldn't be there. In reality there is no Real value of the Design Factor below the cut-off frequency associated with the small diameter. That's a quirk with Excel.
The other thing is that the curvature in your plot looks different than mine.
Perhaps it is because my plot goes to 4 GHz and your plot goes to a frequency not as high ?
Perhaps it is because Excel does not plot the vertical part of the knee of the curve, since to do so would involve fine discretization of the curve near the cut-off point. In any case, if not plotted to 4 GHz, it would be wise to double check it and see what whether they look more alike if you plot it up to 4 GHz.
Thanks. Congratulations again to you persistent digging of Shawyer's literature to understand what he meant by the different variables, particularly lambdg1 and lambdag2.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
Well done.
Nicely rolled cavity walls.
Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?
Doing this will give you some info on how much force you will need to generate to see some movement.
If you happen to be using Excel, I have found the bog standard Solver plug-in very efficacious for problems involving optimisation with several variables. The trick to making it purr is intelligent setting of the constraints.
If microwaves were easily contained there wouldn't be a multi billion dollar industry for the testing and consultation of microwave containment.
Seriously, its a big problem. I was amused by this before but when people start using high powered dirty sources to corrupt bands of the spectrum I get angry. I've processed too many Earth Observing land surface experiments that were corrupted and unusable outside of Canada and the US due to unlicensed device usage. It is perplexing that a forum dedicated to spaceflight would encourage such bad form.
We plan to enclose our system in many layers of laminated microwave absorbing sheets:
http://www.lessemf.com/259.pdf
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
Well done.
Nicely rolled cavity walls.
Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?
Doing this will give you some info on how much force you will need to generate to see some movement.
Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d F=(m*g/h)*d where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10µN/µm. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of µm resolution were used it could probe into µN effects, provided proper casing to isolate from drafts and good damping where strings are suspended.
Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?
The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.
Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
Speaking of safety, do glasses exist that are transparent to visible light and attenuate microwaves?
How about clothing? - chain mail mebbe? :)
(http://i.ytimg.com/vi/crX4E-dul4Y/hqdefault.jpg)
Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
I see two feeds
Interesting isn't it? We just talked about this a few pages ago.Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
I see two feeds
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
Well done.
Nicely rolled cavity walls.
Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?
Doing this will give you some info on how much force you will need to generate to see some movement.
Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d F=(m*g/h)*d where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10µN/µm. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of µm resolution were used it could probe into µN effects, provided proper casing to isolate from drafts and good damping where strings are suspended.
Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?
The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.
Would suggest 1gf / 10mN would be a really good result from this setup.
Based on his published frustum height dimension of 228.6mm, Rf cavity resonance is 1.311GHz or 2.622GHz, which is a bit high for his magnetron. 244.7mm will give resonance at 2.45GHz. Assuming there are no fudge factors to be applied to parallel plate microwave resonance.
one looks like a feed from the signal generator, the other looks like it is going to a power sensor.Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
I see two feeds
It looks like 3.5<something> GHz and I also see "FM". Hmm.
I think LasJayhawk is right about the topmost cable being power sensing
Maybe 3.250 GHz. And the "FM" might simply be "AM"
Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
Recent photo of Shawyer standing next to table top EM Drive experiment:
click here for HD picture with details:
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268#slideshow/1436361
(http://d.ibtimes.co.uk/en/full/1436361/roger-shawyer-inventor-emdrive.jpg?w=350)
The large blue cross shaped device with the humungous waveguide dummy load is a C band directional coupler. The type N connector on the rightmost arm would be connected with coax to more attenuators and then a power meter. Beneath it and obscured by the Agilent frequency generator is what looks like a C band waveguide switch, for directing the RF to the directional coupler or to the blue waveguide to BNC section with coax attached that is feeding the cavity. It's possible the device behind the Agilent signal generator may be the business end of a C band TWT but there isn't much room there so this might just be a staged photo-op.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
Well done.
Nicely rolled cavity walls.
Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?
Doing this will give you some info on how much force you will need to generate to see some movement.
Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d F=(m*g/h)*d where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10µN/µm. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of µm resolution were used it could probe into µN effects, provided proper casing to isolate from drafts and good damping where strings are suspended.
Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?
The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.
An electronic balance isn't a terribly smart idea. But as has been said, this is probably a staged demo.
An electronic balance isn't a terribly smart idea. But as has been said, this is probably a staged demo.
Looks like 3650.3 MHz, 3KHz fm at a 1K rate. But the generators RF out is " off"
Yesterday night i did a new test with the Magnetron moved to the small side (10cm from the small side). I patched the previous hole.
I also put a coil around one magnet in hope to change the frequency.
I ordered a frequency counter, so i will now exactly what is the frequency produced and the intensity.
No pendulum movement was observed. The duration of the test was ~40 sec.
In the future tests i will be able to observe any change in frequency by modifying the current in the coil
If this will not change the frequency i will modify the frustum to add a moving plate inside.
Yesterday night i did a new test with the Magnetron moved to the small side (10cm from the small side). I patched the previous hole.
I also put a coil around one magnet in hope to change the frequency.
I ordered a frequency counter, so i will now exactly what is the frequency produced and the intensity.
No pendulum movement was observed. The duration of the test was ~40 sec.
In the future tests i will be able to observe any change in frequency by modifying the current in the coil
If this will not change the frequency i will modify the frustum to add a moving plate inside.
Moving a small internal end plate back and forth was what Shawyer seemed to do to get his cavity into length resonance.
As per attached.
Would suspect the movable small end plate was very near or at the right end of the cylinder as in the drawing.
Yesterday night i did a new test with the Magnetron moved to the small side (10cm from the small side). I patched the previous hole.
I also put a coil around one magnet in hope to change the frequency.
I ordered a frequency counter, so i will now exactly what is the frequency produced and the intensity.
No pendulum movement was observed. The duration of the test was ~40 sec.
In the future tests i will be able to observe any change in frequency by modifying the current in the coil
If this will not change the frequency i will modify the frustum to add a moving plate inside.
Moving a small internal end plate back and forth was what Shawyer seemed to do to get his cavity into length resonance.
As per attached.
Would suspect the movable small end plate was very near or at the right end of the cylinder as in the drawing.
Yes this is the disk i`m refering. I read almos all this thread and first one, and almost all the papers related to em drive from www.emdrive.com
I bought this counter,i should receive it in a few days.
https://www.youtube.com/watch?v=OUo76oEt1yM.
I want to know if i can change the magnetron frequency. It`s working up to 2,6Ghz and it also has signal strength indicator, so i can check for leaks.
Here you can buy from ebay.
http://www.ebay.com/itm/Black-Mini-Frequency-Counter-IBQ101-Handheld-LCD-Display-HoT-Counter-/171299666945?_trksid=p2054897.l4275
So an EM drive is basically a magnetron that shoots out microwaves? Possibly useful since it doesn't need fuel, but I just wonder what kind of power is required. Any expectations yet?
I'd like to see how this would eventually compare with the ion drive. That would be it's first competitor.
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
Well done.
Nicely rolled cavity walls.
Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?
Doing this will give you some info on how much force you will need to generate to see some movement.
Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d F=(m*g/h)*d where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10µN/µm. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of µm resolution were used it could probe into µN effects, provided proper casing to isolate from drafts and good damping where strings are suspended.
Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?
The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.
Would suggest 1gf / 10mN would be a really good result from this setup.
Based on his published frustum height dimension of 228.6mm, Rf cavity resonance is 1.311GHz or 2.622GHz, which is a bit high for his magnetron. 244.7mm will give resonance at 2.45GHz. Assuming there are no fudge factors to be applied to parallel plate microwave resonance.
I think Shawyer is weighing it, which may be a better setup because the results can be easily quantified. 10 mN would affect its weight measurably, and if a balance were used, the accuracy could be very high.
Todd D.
Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
This is a picture for the FLIGHT THRUSTER case
bD=0.2440 m ;sD=0.1450 m ;cMedium=299705000 m/s (Air)
which has a cut-off frequency associated with the small diameter of 1.21136 GHz
Notice that there is a singularity at 1.21136 GHz such that Shawyer's Design Factor doesn't have a Real value for frequencies below it. Also notice the rise and steepening of the Design Factor curve as the cut-off frequency is approached.
QUESTION: If Shawyer thinks that his Design Factor steepening behavior near the cut-off frequency associated with the small diameter is correct, why didn't he test his Flight Thruster at a lower frequency, closer to 1.2 GHz instead of the higher frequency he chose of 3.782 GHz? Doesn't Shawyer want to maximize thrust force ?
... linear dependency between force (thrust) F and displacement d F=(m*g/h)*d where h is length of strings and m the mass of test article and g local gravity.
....
Would suggest 1gf / 10mN would be a really good result from this setup.
Based on his published frustum height dimension of 228.6mm, Rf cavity resonance is 1.311GHz or 2.622GHz, which is a bit high for his magnetron. 244.7mm will give resonance at 2.45GHz. Assuming there are no fudge factors to be applied to parallel plate microwave resonance.
I think Shawyer is weighing it, which may be a better setup because the results can be easily quantified. 10 mN would affect its weight measurably, and if a balance were used, the accuracy could be very high.
Todd D.
The weight of my setup is 5.9Kg and the height is 1.9 meters.
The power cord setup is far from ideal, maybe you could lead it along one of the suspending wire, starting from the top fixation points, with as thin/supple as possible wires. Also it should be possible to record displacements down to 1/10mm (3mN = .3gf) with a thin needle flying close above millimetre graph paper and filming closer, in macro mode or through magnifying lens ?Point a fixed laser to a small slit on the device. Place a target on the other side of the room. The diffraction pattern should change with microscopic variations of position.
The Design Factor has little dependence on frequency, except near the cut-off frequency. The Design Factor of Shawyer asymptotically approaches this value for high frequencies (it becomes practically independent of frequency)Do people in this thread even realize that this would boil down to a contradiction with radiation pressure measurements dating back over 100 years?
Do you "even realize" that people in this thread already realized this, and this is addressed earlier in this thread, in a much more comprehensive and technical manner? ;)The Design Factor has little dependence on frequency, except near the cut-off frequency. The Design Factor of Shawyer asymptotically approaches this value for high frequencies (it becomes practically independent of frequency)Do people in this thread even realize that this would boil down to a contradiction with radiation pressure measurements dating back over 100 years?
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
I have read the draft and although I can't vouch for the maths (my skills are way below what is required - as soon as tensors are involved I have to give up) the concepts do make sense to me. This is most definitely interesting and it would be a great result if we could measure this gravitational effect with an interferometer setup.
I have a question: if there is a gravitational effect in the cavity, how is this effect distributed? Is it symmetric? And what is the entity of it, quantitatively?
I am reasoning that if there is an asymmetry in the gravitational effect and the cavity is filled with a perfect gas (or even just air), then in principle there will be a pressure gradient within the cavity causing a (very small?) average density gradient.
In absence of an external gravity field, this is irrelevant. And certainly it would not generate any thrust on its own...
However, if this density gradient is immersed in a gravity field (like Earth's) the apparatus will weigh more on one side than the other. This will generate a (very very small?) torque trying to twist the apparatus until the gradient aligns with the gravity field.
Could this torque create a displacement affecting the experiment in a way that can be confused with thrust? Could the experiment be susceptible to this particular condition? (I'm thinking that that pendulum-suspended EmDrive looks like it would be affected by differences in the weight distribution of the device)
One more reason to perform experiments in a vacuum, I guess...
QUESTION: If Shawyer thinks that his Design Factor steepening behavior near the cut-off frequency associated with the small diameter is correct, why didn't he test his Flight Thruster at a lower frequency, closer to 1.2 GHz instead of the higher frequency he chose of 3.782 GHz? Doesn't Shawyer want to maximize thrust force ?
3D Plot of Shawyer's Design Factor vs. frequency and vs. small diameter; for same big diameter as Flight Thruster, but with the small diameter ranging from zero to same size as big diameter.
Remember: according to Shawyer the Design Factor multiplies the Power Input and the Q. The higher the Design Factor, the higher the thrust of the EM Drive, the smaller the Design Factor, the smaller the thrust.
Observe that at high frequency, the Design Factor changes almost linearly with small diameter, such that the Design Factor goes to zero as the small diameter approaches the big diameter.
The Design Factor approaches 1 for the small diameter approaching zero.
As the small diameter approaches zero, the cut-off frequency clips the Design Factor, such that to be able to have a smaller small diameter one has to operate at higher frequency (in order to avoid cut-off).
A very nice feature of Shawyer's Design Factor (as opposed to McCulloch's formula) is that Shawyer's Design Factor incorporates the cut-off frequency and hence it prevents consideration of a pointy cone, as the cut-off prevents too small of a small diameter to be considered.
The highest value of the Design Factor is reached at frequencies just a little over the cut-off frequency for the small end:
Cut-Off frequency for small end= cM/(cst*sD)
where
sD= small end diameter (m)
cst=1.7062895542683174
cM = light speed in selected medium (m/s)
= 299705000 (m/s) (speed of light in air)
= 299792458 (m/s) (speed of light in vacuum)
The Design Factor has little dependence on frequency, except near the cut-off frequency. The Design Factor of Shawyer asymptotically approaches this value for high frequencies (it becomes practically independent of frequency)
Limit[DesignFactor, f -> Infinity] = (bD^2 - sD^2)/(bD^2 + sD^2)
where
bD = big end diameter (m)
sD= small end diameter (m)
Whether Shawyer's Design Factor is correct, remains to be proven. For example, Shawyer's Design Factor predicts that the smaller the small diameter the better (hence larger cone angles, for constant frustum length), in contrast with Todd's conjecture that the highest attenuation the better (which leads to small cone angles ~7.5 degrees as the optimal design).
Reference: formula for Design Factor here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110
designFactor =
(bD^2 - sD^2)/( (bD^2)*Sqrt[1 - (cM/(bD*cst*f))^2] + (sD ^2)*Sqrt[1 - (cM/(cst*f*sD))^2] )
bD = big end diameter (m)
sD= small end diameter (m)
f = applied frequency (Hz)
cst=1.7062895542683174
cM = light speed in selected medium (m/s)
= 299705000 (m/s) (speed of light in air)
= 299792458 (m/s) (speed of light in vacuum)
The main result of the paper is that the gravitational effects are proportional to the energy density of the electromagnetic field inside the cavity (roughly speaking). This means that the electromagnetic field inside the cavity determines the way the gravitational field is distributed. A change could be due to the proportionality factor L(x). Of course, there could be an effect due to the Earth gravitational field but I did not estimate it yet.
The main result of the paper is that the gravitational effects are proportional to the energy density of the electromagnetic field inside the cavity (roughly speaking). This means that the electromagnetic field inside the cavity determines the way the gravitational field is distributed. A change could be due to the proportionality factor L(x). Of course, there could be an effect due to the Earth gravitational field but I did not estimate it yet.
So, if I understand correctly, L(x) is purely a function of the position "x vector" obtained by a defined volume integral, and is only dependent on the geometry of the cavity and the l0 (ell zero) constant which depends on U0 which depends on the source energy.
In Equation 37, given a defined geometry of the frustum, "a" is later determined to be a constant term, "b" is also a constant term, so the shape of the function depends on the logarithm and the square of "r vector".
However Equation 38 sets a condition by which "r vector" is linear to "z vector". Does this mean that "r vector" is a function of z, i.e. it varies with the position on the height axis of the frustum?
Am I understanding it correctly?
If that is the case, then the gravitational effect is stronger towards one plate than the other. Which leads to my concerns about a torque being present rather than a thrust. Presumably, in an experiment the frustum is suspended or supported in such a way that a static balance is achieved; however if a torque is present the balance is altered and this could potentially be confused for a thrust depending on how the mechanical parts of the experiment are set up.
(I've realised that there could be a torque even in vacuum because you can't remove the existence of the frustum itself, and its weight distribution could change with the gravitational effect)
But again, I'm not 100% sure I'm understanding this correctly. I'm just throwing ideas for the smarter people to think about. I hope this is useful.
Went back to investigate what I reported in post #233 http://forum.nasaspaceflight.com/index.php?topic=36313.msg1318683#msg1318683 about the RF and Microwave Toolbox app. I found that the app is reporting the correct solutions for TE and TM. The help file just had a typo. I verified it against the KWOK lectures http://www.engr.sjsu.edu/rkwok/EE172/Cavity_Resonator.pdf slide 16. KWOK and the APP match. So this works as a quick and easy way to find resonant modes! There really is an app for everything.
I remain unconvinced that calculating resonant modes for cylinders is a good approximation for conical frustums though.
Besides, contributions from Earth gravitational field are damped by a factor (Schwarzschild radius)/(Earth radius) where the Schwarzschild radius of the Earth is 9 mm while the Earth radius is about 6000 km. This factor being 10^(-12) makes negligible the effect with respect to the behaviour of the electromagnetic field inside the cavity.
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimensions of the bottom Rf connector flange, we can set pixels per cm and start doing measurements.
Went back to investigate what I reported in post #233 http://forum.nasaspaceflight.com/index.php?topic=36313.msg1318683#msg1318683 about the RF and Microwave Toolbox app. I found that the app is reporting the correct solutions for TE and TM. The help file just had a typo. I verified it against the KWOK lectures http://www.engr.sjsu.edu/rkwok/EE172/Cavity_Resonator.pdf slide 16. KWOK and the APP match. So this works as a quick and easy way to find resonant modes! There really is an app for everything.
I remain unconvinced that calculating resonant modes for cylinders is a good approximation for conical frustums though.
The problem as I see it with the cylindrical resonate model to the (in progress) frustum resonate model is in the cylinder model the guide wavelength / frequency stays the same from one end to the other, while in the frustum, the guide wavelength / frequency continually varies as the diameter varies.
As example in your frustum big end = 0.2797m dia & small = 0.1588m dia and 2.45GHz applied Rf frequency.
Guide wavelengths / frequencies:
big end = 0.12654m / 2.368,462,699Ghz
small end = 0.13703m / 2.187,156,644GHz
diff (big-small) = -0.010490m / 0.181,306,055GHz
Data attached.
These are guide wavelength / frequency and NOT cut off wavelength/frequencies. At 2.45GHz, both of your ends operate well above cutoff.
So for your frustum, operating at 2.45GHZ, there is a 181.3MHz difference in the guide frequencies at each end.
Trying to imagine what this would look like. Can easily see a cylindrical model with constant guide wavelength from end to end.
I may be wrong but as I see it cavity resonance occurs at the internal guide wavelength and not at the external applied Rf wavelength. We know the guide frequency at each end of the frustum, so how to get the applied Rf frequency that causes end plate to end plate resonance at 1/2 wave or other harmonic of some internal guide frequency?
You can get a reasonably close approximation to the exact expression for the natural frequencies of a truncated cone
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimensions of the bottom Rf connector flange, we can set pixels per cm and start doing measurements.
Most N connectors like that are 1" square, and the holes are .718" center line to center line.
Pixel away. :)
The exact expression for the solution to Maxwell's equations in a truncated cone involves the solution of two eigenvalue problems, one in terms of Legendre Associated functions and the other one in terms of spherical Bessel functions. Take a gander at this http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html for an exact expression (Egan only gives the exact solution for TE0np and TM0np modes, not valid for TM212 for example), so that you can see that it would be unwieldly to program it in Excel.You can get a reasonably close approximation to the exact expression for the natural frequencies of a truncated cone
What is the "exact expression for the natural frequencies of a truncated cone"?
Why go with close estimates?
The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
If you tell me specifically what measure you are trying to find, and what measures you know with regards to the photo, I might be able to help.Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimensions of the bottom Rf connector flange, we can set pixels per cm and start doing measurements.
Most N connectors like that are 1" square, and the holes are .718" center line to center line.
Pixel away. :)
Thanks. Have fine rotated to vertical / horizontal and lined up. Attached if anyone else wants to have a go.
The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
That's what I'm talking about! Something like this would be at least 20% more efficient than an EM Drive could ever be. IMO, no competition...
Todd D.
The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
That's what I'm talking about! Something like this would be at least 20% more efficient than an EM Drive could ever be. IMO, no competition...
Todd D.
I can see future development that includes optical cavities that span many kilometers achieved with precise mirror alignment to enable maneuvering spacecraft many kilometers apart, and propellant-free propulsion of satellites in formations.
How do you figure that?The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
That's what I'm talking about! Something like this would be at least 20% more efficient than an EM Drive could ever be. IMO, no competition...
Todd D.
If you tell me specifically what measure you are trying to find, and what measures you know with regards to the photo, I might be able to help.Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimensions of the bottom Rf connector flange, we can set pixels per cm and start doing measurements.
Most N connectors like that are 1" square, and the holes are .718" center line to center line.
Pixel away. :)
Thanks. Have fine rotated to vertical / horizontal and lined up. Attached if anyone else wants to have a go.
The size of the rectangular section the Flight Thruster is sitting on and the size of the Rf connector flange and mounting hole spacing should be knowable.The one "known" is the 1" N connector. Notice that it is slightly off-centre because 1) the top is more distant than the bottom (frustum angle) and 2) it does not lie exactly face-on to the image plane, but rather a little around the circumference to the left. Fortunately we can correct for both of these small changes fairly exactly.
Yesterday night i did a new test with the Magnetron moved to the small side (10cm from the small side). I patched the previous hole.
I also put a coil around one magnet in hope to change the frequency.
I ordered a frequency counter, so i will now exactly what is the frequency produced and the intensity.
No pendulum movement was observed. The duration of the test was ~40 sec.
In the future tests i will be able to observe any change in frequency by modifying the current in the coil
If this will not change the frequency i will modify the frustum to add a moving plate inside.
Moving a small internal end plate back and forth was what Shawyer seemed to do to get his cavity into length resonance.
As per attached.
Would suspect the movable small end plate was very near or at the right end of the cylinder as in the drawing.
Yes this is the disk i`m refering. I read almos all this thread and first one, and almost all the papers related to em drive from www.emdrive.com
I bought this counter,i should receive it in a few days.
https://www.youtube.com/watch?v=OUo76oEt1yM.
I want to know if i can change the magnetron frequency. It`s working up to 2,6Ghz and it also has signal strength indicator, so i can check for leaks.
Here you can buy from ebay.
http://www.ebay.com/itm/Black-Mini-Frequency-Counter-IBQ101-Handheld-LCD-Display-HoT-Counter-/171299666945?_trksid=p2054897.l4275
The search function aren't that super here euuuuu.To be blunt, it totally sucks :(
The search function aren't that super here euuuuu.
Why is the RF injected into the side of the EM Device. I know it's a basic question but can someone expand on it a little more?
Shells
About Bae's PLT:
The technique will come into its own when alignment over at least one million Km is feasible.
Now you'll notice that they were in a clean room (albeit in air) so that should give pause to anyone considering using this as a launch system for extremely light payloads directly from Earth's surface. Nevertheless, a little noodling would not go amiss on this topic.
The available motive power is Q*P (Q=200, P=800 W in the video), so the force F = 2*Q*P/c (1.1 mN in the video), so the acceleration a = F/m (m=0.45 Kg, a = 2.5 mm/s2 in the video).
What would it take to get up to 1 gee for an Earth-based launch?
The acceleration needs to be increased by a factor of ~4000x.
Putting this all together we get
a = 2 Q P / (m c)
Leaving m alone for the moment, Bae states that Q could improve by a factor ~5x (200->1000).
Now we need 4000/5 = 800x improvement.
Using a 800 kW laser does that for us (1000x).
Alternatively we can use a lower mass and thus a lower power laser.
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimensions of the bottom Rf connector flange, we can set pixels per cm and start doing measurements.
Most N connectors like that are 1" square, and the holes are .718" center line to center line.
Pixel away. :)
Thanks. Have fine rotated to vertical / horizontal and lined up. Attached if anyone else wants to have a go.
Random thought but;
1- Could someone please try an em cavity with the bottom (large curved end) not electrically bonded to the sidewalls & top. ie place a circular insulating gasket between the contact point of the sidewall bottom edge and the actual bottom curved plate, just the wall/plate boundary NOT covering the internal surface area of the curved plate.
Accurate to about 5% = 1-cos(18o). Could be better were you to use my observation about the distortion in the 1" dimensions.
Random thought but;
1- Could someone please try an em cavity with the bottom (large curved end) not electrically bonded to the sidewalls & top. ie place a circular insulating gasket between the contact point of the sidewall bottom edge and the actual bottom curved plate, just the wall/plate boundary NOT covering the internal surface area of the curved plate.
What do you think will be different if the bottom plate is electrically insulated?
I think we could easily incorporate this into our design, we have planned to leave a small clearance between the bottom movable plate and the frustum. Our bottom plate may not be as curved as Shawyer's, but we'll be able to provide a small amount of curvature by tighting the screws to different lengths.
Random thought but;
1- Could someone please try an em cavity with the bottom (large curved end) not electrically bonded to the sidewalls & top. ie place a circular insulating gasket between the contact point of the sidewall bottom edge and the actual bottom curved plate, just the wall/plate boundary NOT covering the internal surface area of the curved plate.
What do you think will be different if the bottom plate is electrically insulated?
I think we could easily incorporate this into our design, we have planned to leave a small clearance between the bottom movable plate and the frustum. Our bottom plate may not be as curved as Shawyer's, but we'll be able to provide a small amount of curvature by tighting the screws to different lengths.
After building the 3D-Model I'm 'fairly certain' there is a rubber gasket between the end plates and cone. It's 1/16 of an inch thick in the model which reflects what I see in the image.
The search function aren't that super here euuuuu.
Why is the RF injected into the side of the EM Device. I know it's a basic question but can someone expand on it a little more?
Shells
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
The search function aren't that super here euuuuu.Beats me. And it looks like the placement would put part of the big end in the near near field and loading the bejesus out of the source.
Why is the RF injected into the side of the EM Device. I know it's a basic question but can someone expand on it a little more?
Shells
The search function aren't that super here euuuuu.
The biggest danger, in my understanding, is cooking your eyes. The thermal conductivity is very low and there are no pain receptors.Have modified my Shawyer Df calculator and best Df scanner as per the derived Shawyer Df equation, using cutoff wavelength and guide wavelength as per microwave industry supplied equations. I assume Shawyer did not supply these equations in his papers as they are equations that should be known to microwave industry individuals skilled in the art. Anyway they are now in the public record.
The scanner still sweeps the frequency range 0Hz to 10GHz but reports the frequency that generates a Df as close to 1 as possible but not over.
The attached results are very interesting as the frequency needed to get the Df to just below 1 is very close to the Rf driving frequency used to generate Lambda0 or free wavelength in the selected medium.
While I'm still testing the spreadsheet, which meets both of Shawyers boundary conditions, the results for my Flight Thruster design are looking to be very close to what I could build. Bit of dimension tweaking should get the Df 1 frequency to the 3.85GHz Shawyer used.
Will post the spreadsheet after a bit more testing.
I've built and tested many microwave cavities over many years.
You're guided wavelength equation is wrong, because this is for a rectangular wave guide (i.e., not even a rectangular cavity)
You need to derive mode of frequency yourself (unless there is a paper somewhere) for a circular tapered cavity. There is no other way around it. I would start with Balanis - Advanced Engineering Electromagnetics as he derives a few examples for other topologies. Right now everything you are doing is wrong because you don't understand the physics. I would study that book from front to cover if I were you.
Also, to the guy operating the microwave magnetron outside of the microwave: STOP
At best you are violating the laws of your local government's regulatory committee for the electromagnetic spectrum. At worst you will damage your body. At this frequency, the damage is somewhat insidious. Due to low water content of your skin, you don't feel the heat, but internal nerve endings can be damaged so that chronic phantom pain can appear. Sometimes days after exposure. Please STOP otherwise you will inevitably be reported to your government.
Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
Thanks James!The search function aren't that super here euuuuu.
Why is the RF injected into the side of the EM Device. I know it's a basic question but can someone expand on it a little more?
Shells
No one else has chimed in, so I'll give this a shot. ;)
I believe the choice of antenna position is predominantly a function of the antenna beam pattern, and the desire to couple maximum energy into the cavity.
A simple dipole antenna radiates/couples well in the perpendicular direction, so placing a dipole antenna perpendicular to the cavity wall would allow direct coupling into the dominant resonant direction (i.e. between the concave/convex end plates).
(attached image from http://www.trevormarshall.com/byte_articles/byte1.htm (http://www.trevormarshall.com/byte_articles/byte1.htm))
I had proposed (many pages back) that the use of a waveguide to inject a magnetron's signal had the effect of a directional beam pattern that was much better at injecting energy than removing energy from the cavity. (since resonanting energy is dominantly between the end plates, a waveguide input roughly perpendicular to the walls would inject energy better than remove energy) However, I'll readily admit my reasoning may be overly simplistic.
Thanks,
James
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
Good Point ! But volume integral ? 0 to ... ((r2-r1)/h) z' + r1 /l0 ? (seems circular that way)
It's Eq. 18 that still bothers me a bit. Invoking the Heaviside step function is OK, but I don't see the addl. components being detectable outside the cavity w/o a non-linear term. Maybe I'm missing something ?
A constant force produces a constant acceleration, unless you are prepared to abandon Isaac-baby. Where was it? Coupled [sic] with which, the table contained several rotating devices like fans and a hard drive.Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
The Dynamic Tests of the EM Drive showed a slowly rotating table top of machinery. So sufficient force was being produced to move the equipment 2 metres in a few minutes.
A constant force produces a constant acceleration, unless you are prepared to abandon Isaac-baby. Where was it? Coupled [sic] with which, the table contained several rotating devices like fans and a hard drive.Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
The Dynamic Tests of the EM Drive showed a slowly rotating table top of machinery. So sufficient force was being produced to move the equipment 2 metres in a few minutes.
You're right it was with hard drives and fans, but weren't they running before they switched on the EM Drive?A constant force produces a constant acceleration, unless you are prepared to abandon Isaac-baby. Where was it? Coupled [sic] with which, the table contained several rotating devices like fans and a hard drive.Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
The Dynamic Tests of the EM Drive showed a slowly rotating table top of machinery. So sufficient force was being produced to move the equipment 2 metres in a few minutes.
How do you figure that?The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
That's what I'm talking about! Something like this would be at least 20% more efficient than an EM Drive could ever be. IMO, no competition...
Todd D.
Anyone seen this little tidbit?Sorry, but, as one commenter notes: "Egregious click-bait"
http://phys.org/news/2015-05-newton-law-broken.html
Excellent point! Unless of course they had clamped the table until the EmDrive was switched on :)You're right it was with hard drives and fans, but weren't they running before they switched on the EM Drive?A constant force produces a constant acceleration, unless you are prepared to abandon Isaac-baby. Where was it? Coupled [sic] with which, the table contained several rotating devices like fans and a hard drive.Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
The Dynamic Tests of the EM Drive showed a slowly rotating table top of machinery. So sufficient force was being produced to move the equipment 2 metres in a few minutes.
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I'm glad someone understands how the EmDrive works!!How do you figure that?The competition
http://nextbigfuture.com/2015/05/photonic-laser-thruster-has-moved-one.html
That's what I'm talking about! Something like this would be at least 20% more efficient than an EM Drive could ever be. IMO, no competition...
Todd D.
Because, IMO the EM Drive has no thrust without losses. Resonating modes do not exert any NET force. It is the attenuation of evanescent modes that provide whatever thrust can be had.
Anyone seen this little tidbit?Sorry, but, as one commenter notes: "Egregious click-bait"
http://phys.org/news/2015-05-newton-law-broken.html
I'm glad someone understands how the EmDrive works!!
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
Good Point ! But volume integral ? 0 to ... ((r2-r1)/h) z' + r1 /l0 ? (seems circular that way)
It's Eq. 18 that still bothers me a bit. Invoking the Heaviside step function is OK, but I don't see the addl. components being detectable outside the cavity w/o a non-linear term. Maybe I'm missing something ?
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
Good Point ! But volume integral ? 0 to ... ((r2-r1)/h) z' + r1 /l0 ? (seems circular that way)
It's Eq. 18 that still bothers me a bit. Invoking the Heaviside step function is OK, but I don't see the addl. components being detectable outside the cavity w/o a non-linear term. Maybe I'm missing something ?
1) Good point about Eq. 18: how do those harmonic components make it outside the cavity? Do they go outside the cavity because of the small transparent portholes on the EM Drive through which the interferometer laser beam is going through?
2) If one wants to nondimensionalize the expression, it would have to be
r1/lo to ((r2-r1)/h) z'/l0 + r1 /l0
instead of
0 to ((r2-r1)/h) z' + r1 /l0
and since
zbar= z/l0
zbar' = z'/l0
then
r1 /l0 to (r2-r1)/h) zbar' + r1 /l0
but the last integral would have to be on drbar' instead of on dr'
and the first integral would have to be on dzbar' instead of on dz,
and the first integral would have to be over
0 to h/lo
instead of
0 to h
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.In page 8, equation 34 of http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137,
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
for the integral on dr', should the limits, instead of
0 to ((r2-r1)/h) z' + r2
be
r1 to ((r2-r1)/h) z' + r1 ?
Good Point ! But volume integral ? 0 to ... ((r2-r1)/h) z' + r1 /l0 ? (seems circular that way)
It's Eq. 18 that still bothers me a bit. Invoking the Heaviside step function is OK, but I don't see the addl. components being detectable outside the cavity w/o a non-linear term. Maybe I'm missing something ?
That's interesting. The effect of the modified geometry is to couple the resonant mode of the cavity with the external source that in this case is a laser beam. This enters into the correction factor L(v) (sorry for the unfortunate choice of the notation, this is not the same L I use below). I do a first order computation to uncover such a coupling.
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
Or a sufficient shift in the centre of mass, for a non perfectly vertical axis.Yes. And the way to silence sceptics is to make measurements on a fully-boxed rig - including battery. All these trailing feeds generate pseudo-forces. That would be OK if thrust were Newton level - but it ain't, so it ain't.
The Dynamic Tests of the EM Drive showed a slowly rotating table top of machinery. So sufficient force was being produced to move the equipment 2 metres in a few minutes.
It is interesting that one of the things that Landsberg shows in 1979 is that the following is not longer true in a gravitational field:
"Thermal equilibrium is equivalent to having a system at uniform temperature throughout"
https://goo.gl/IFeT48 Some of it is missing. Hope it is enough to help.Nice little treasure trove, good work! Quick reading of some of it seems to be what I've been looking for in one clump. Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!
Stuff I dug up that I'm studying that may be useful to others:
http://benasque.org/2011qfext/talks_contr/2019_Buhmann.pdf
http://library.naist.jp/dspace/bitstream/10061/9833/1/PhysRevLett.113.235501.pdf (very cool)
http://pf.is.mpg.de/assets/ph500305z.pdf
http://www.nature.com/srep/2013/130313/srep01444/full/srep01444.html
...Ivan Sokolnikoff? Which book ? His Higher Math book, his Tensor Analysis book or his less known book with Rainich on the mathematics of relativity ?
(Heh! Just found Sokolnikoff, noticed all the markup in in chap.4...was working on "Hamiltonian" radar then .... I need to read chap. 3 ! Opps maybe I did ...."Surfaces in space is marked up! Hard gettin' old....)
...Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!Not sure about that...wonder how much individual thought process, creativity and imagination is overwhelmed by the huge amount of information available from the Internet nowadays. Many scientists think that it may have the opposite effect on individual intelligence and thought process as the mind needs as much or more exercise (to produce connections of neurons, etc.) as human muscles. With so many "answers" freely available at a click of one's fingers, there is much less exercise of one's brain :)
I also like the classic (unabridged) Tensor Analysis book by Schouten ("Ricci-Calculus" the one over 500 pages long) :)...Ivan Sokolnikoff? Which book ? His Higher Math book, his Tensor Analysis book or his less known book with Rainich on the mathematics of relativity ?
(Heh! Just found Sokolnikoff, noticed all the markup in in chap.4...was working on "Hamiltonian" radar then .... I need to read chap. 3 ! Opps maybe I did ...."Surfaces in space is marked up! Hard gettin' old....)
Tensor Analysis, '64 edition
I also like the classic (unabridged) Tensor Analysis book by Schouten ("Ricci-Calculus" the one over 500 pages long) :)...Ivan Sokolnikoff? Which book ? His Higher Math book, his Tensor Analysis book or his less known book with Rainich on the mathematics of relativity ?
(Heh! Just found Sokolnikoff, noticed all the markup in in chap.4...was working on "Hamiltonian" radar then .... I need to read chap. 3 ! Opps maybe I did ...."Surfaces in space is marked up! Hard gettin' old....)
Tensor Analysis, '64 edition
...Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!Not sure about that...wonder how much individual thought process, creativity and imagination is overwhelmed by the huge amount of information available from the Internet nowadays. Many scientists think that it may have the opposite effect on individual intelligence and thought process as the mind needs as much or more exercise (to produce connections of neurons, etc.) as human muscles. With so many "answers" freely available at a click of one's fingers, there is much less exercise of one's brain :)
...Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!Not sure about that...wonder how much individual thought process, creativity and imagination is overwhelmed by the huge amount of information available from the Internet nowadays. Many scientists think that it may have the opposite effect on individual intelligence and thought process as the mind needs as much or more exercise (to produce connections of neurons, etc.) as human muscles. With so many "answers" freely available at a click of one's fingers, there is much less exercise of one's brain :)
I almost always find myself agreeing with you Dr. Rodal, but will respectfully and lightheartedly disagree with you on this. I've heard others take the same position. My experience and observation have been quite the opposite. Those who I know who are Internet savvy, are aware of and participate in online forums, are willing to do deep dives into knowledge areas at a whim using the Internet, are some of the most highly informed and highly evolved people that I know.
Some argue that the quality of information freely available is less than stellar. Again, I would disagree with that notion as well. Wikipedia, for example, has been found to be more accurate in recent years than most printed encyclopedias.
Hooorrrrahh for the Internet, which enables open science pertaining to space flight and other topics, the quick dissemination of information, world-wide collaboration, the trembling of despots, and the dawning of a new age of freedom.
Notice the reference to space flight in my ranting. :)
That's the truth!...Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!Not sure about that...wonder how much individual thought process, creativity and imagination is overwhelmed by the huge amount of information available from the Internet nowadays. Many scientists think that it may have the opposite effect on individual intelligence and thought process as the mind needs as much or more exercise (to produce connections of neurons, etc.) as human muscles. With so many "answers" freely available at a click of one's fingers, there is much less exercise of one's brain :)
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
It is interesting that one of the things that Landsberg shows in 1979 is that the following is not longer true in a gravitational field:
"Thermal equilibrium is equivalent to having a system at uniform temperature throughout"
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
I missed something. Did you write a paper about? Please, let me know as I have not followed this discussion from the start.
...Gads I love the internet and wished it was there when I was going to school. I'm not ready to throw the slab of idea and thought meat into the shark pool yet but thanks for the links!!! Kudos!Not sure about that...wonder how much individual thought process, creativity and imagination is overwhelmed by the huge amount of information available from the Internet nowadays. Many scientists think that it may have the opposite effect on individual intelligence and thought process as the mind needs as much or more exercise (to produce connections of neurons, etc.) as human muscles. With so many "answers" freely available at a click of one's fingers, there is much less exercise of one's brain :)
Hopefully not a future of people thinking that Physics and Engineering is just a question of getting answers from a huge Internet cookbook of recipes and from black-box computer software instead of using mathematics and experiments to find out how Nature operates...
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
I missed something. Did you write a paper about? Please, let me know as I have not followed this discussion from the start.
FYI
Cleanup and detypo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi*f) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
---------------------------------------------------------------------------------------------------------------------------
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
I missed something. Did you write a paper about? Please, let me know as I have not followed this discussion from the start.
FYI
Cleanup and detypo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi*f) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
---------------------------------------------------------------------------------------------------------------------------
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
I missed something. Did you write a paper about? Please, let me know as I have not followed this discussion from the start.
FYI
Cleanup and detypo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi*f) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
---------------------------------------------------------------------------------------------------------------------------
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
The accelerated frame or reference in which the asymmetry of the cavity is balanced out. That is as though the cavity was cylindrical in this case. Notice you would probably need the coordinate changes to do this as a proper derivation. As we said, that might have to constitute a (mathematical) proof.
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
...Watch out for errors on the transcription to LaTeX pdf http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830511
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
Thank you ! I'll look up LaTex (new to me) How does one edit the pdf ? ( df should be delta f, for example)
Its the (taking the extremes of the) equivalent wavelength change along the cavity axis of the resonant frequency in the rest frame. It should really be the result of an integral over that length to get a more general case ( included dielectrics for example )
...Watch out for errors on the transcription to LaTeX pdf.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
For example, first equation (1) reads 2c/Pi instead of c/(2*Pi)
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830511
Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/
https://www.youtube.com/watch?v=2-cgVoLUJ8w
...Watch out for errors on the transcription to LaTeX pdf.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
For example, first equation (1) reads 2c/Pi instead of c/(2*Pi)
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830511
Fixed. Thanks.
...Watch out for errors on the transcription to LaTeX pdf.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
For example, first equation (1) reads 2c/Pi instead of c/(2*Pi)
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830511
Fixed. Thanks.
It would be helpful to mark revision number both inside the file and in the title. Maybe with a date inside.
Anyone seen this little tidbit?Non-equiibrium thermodynamics
http://phys.org/news/2015-05-newton-law-broken.html
I have to find my old copy of the book by S. R. De Groot, P. Mazur and other such books I have in boxes
and see whether we can derive a force for the EM Drive based on Onsager's relations :)
Still looking for my copy as well ! (old cavity work was on transport properties)
The system in that paper is not isolated from the environment. For EM Drive this is not true. You have to cope with a closed system and to understand why third law appears to be violated, if the effect is confirmed
Yup !
Do you remember if DeGroot mentioned photons ?
That book is rather old. I just gave a cursory look and found nothing about photons. You should rather consider the case for electromagnetic radiation. What could make the thing resemble that of a non-isolated system is leakage of radiation out of the cavity. I have to guess that one has built it reducing such losses. The idea to look at gravitational effects, started by Minotti's paper, is because in this case there is not a boundary due to the cavity and system appears to be open (space-time is everywhere). So, the third law would be saved by the expulsion of gravitational momentum. The reason why people in the community of scientists did not consider the case is the smallness of the gravity with respect to all other effects and so, one should not expect it to account for such a measurement.
As you can see from my crude dispersion argument, the g value (of the photons) is much larger than one might naively expect.
"In the accelerated frame of reference w/ the acceleration, g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2)) [for this waveguide-like approximation]."
I missed something. Did you write a paper about? Please, let me know as I have not followed this discussion from the start.
FYI
Cleanup and detypo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
For TM modes, X = X[sub m,n] = the n-th zero of the m-th Bessel function.
[1,1]=3.83, [0,1]=2.40, [0,2]=5.52 [1,2]=7.02, [2,1]=5.14, [2,2]=8.42, [1,3]=10.17, etc.
and for TE modes, X = X'[subm,n] = the n-th zero of the derivative of the m-th Bessel function.
[0,1]=3.83, [1,1]=1.84, [2,1]=3.05, [0,2]=7.02, [1,2]=5.33, [1,3]=8.54, [0,3]=10.17, [2,2]=6.71, etc.
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
and from there the expression for the acceleration g from:
g = (c^2/L)*(df/f) such that:
g = (c^2/(2*L*f^2))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
Using the "weight" of the photon in the accelerated frame from:
"W" = (h*f/c^2)*g => "W" = T = (h/L)*df
gives thrust per photon:
T = (h/(2*L*f))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
If the number of photons is (P/hf)*(Q/2*pi*f) then:
NT = P*Q*(1/(4*pi*L*f^3))*(c/(2*pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
This does fit (as far as I've gotten) the concept of a self-accelerating Dirac wavepacket (which does conserve momentum).
---------------------------------------------------------------------------------------------------------------------------
Yes the search function is terrible
df is delta f not the differential, Q is the effective Q due to phase shift etc.
I have put your text in a LaTeX format and enclose it here. But the question is: Where does your acceleration come from?
4) Also this link may be helpful, giving a table of the Xmn and X'mn to 15 digits accuracy
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
Thanks. That link ( https://www.wolframalpha.com/input/?i=besseljzero[1%2C1 ) only gives Xmn which are only useful for TM modes4) Also this link may be helpful, giving a table of the Xmn and X'mn to 15 digits accuracy
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
Try:
Wolfram alpha (https://www.wolframalpha.com/input/?i=besseljzero[1%2C1)
Is there a way that Wolfram Alpha can give X'mn which are needed for TE modes ?
OK, yes, that's helpful to the people that have Mathematica. They can program that function ( notice that X'mn is not a buil-in function in Mathematica yet). To those that don't have Mathematica, that's the great usefulness of this link http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx: it gives X'mn to 15 digits accuracy and it is accessible to everyone.Thanks. That link ( https://www.wolframalpha.com/input/?i=besseljzero[1%2C1 ) only gives Xmn which are only useful for TM modes4) Also this link may be helpful, giving a table of the Xmn and X'mn to 15 digits accuracy
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
Try:
Wolfram alpha (https://www.wolframalpha.com/input/?i=besseljzero[1%2C1)
Is there a way that Wolfram Alpha can give X'mn which are needed for TE modes ?
I don't think so. But I believe you have Mathemagica:
http://www.me.rochester.edu/courses/ME201/webexamp/derbesszer.pdf - see ln67
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
These equations appear rather interesting as, by a proper choice of parameters, one can make a gravitational effect more or less relevant in the physics of the problem. It is the case to say that geometry comes to rescue.
...
FYI
Cleanup and detypo of the take on applying the Equivalence Principle.
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)
Starting with the expressions for the frequency of an RF cavity:
f = (c/(2*Pi))*((X/R)^2+((p*Pi)/L)^2)^.5
....
Rotate the dispersion relation of the cavity into doppler frame to get the Doppler shifts, that is to say, look at the dispersion curve intersections of constant wave number instead of constant frequency.
df = (1/(2*f))*(c/(2*Pi))^2*X^2*((1/Rs^2)-(1/Rb^2))
...
...
It comes from "work" done by the waves on the copper, i.e. EM induction, which slows down the wave and steals it's momentum. It mimics gravity in this regard, because photons lose energy going "up".
I'm still working on a slightly different version of this. My time has been severely limited this past week however.
Todd D.
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
Marco, your paper, after equation 39, has this interesting comment:Quote from: FrascaThese equations appear rather interesting as, by a proper choice of parameters, one can make a gravitational effect more or less relevant in the physics of the problem. It is the case to say that geometry comes to rescue.
Just what this "proper choice of parameters" is, it is not spelled out in your paper, so I will follow my interpretation of your equation.
It appears (see proof below) that in order to maximize the constants "a" and "b" in Equation 39, we want to have:
1) r1 as close as possible to r2
2) r2 as large as possible
Now, if this is correct, this is a rather peculiar, surprising geometry: it says that the axial length of the truncated cone should be close to zero while the radius should be as large as possible, in other words, the geometry should be as close to an almost perfect cylinder (small cone angle) with very short axial length, and with flat faces. In other words, this optimized geometry, according to Eq. 39 in your paper seems to be much closer to Cannae's device.
And it is actually not far from the geometry presently used by Dr. White. It is certainly not the geometry of a cone
(http://1.bp.blogspot.com/-2MORMyXf97o/VU4f2f8MtII/AAAAAAAA90w/Oc5eLpuujA4/s400/cannae_driveNASA.jpg)
However (see below), we also conclude that the maximum possible values of the constants b (and also a) are extremely small and hence they are negligible unless the EM Drive happens to be near a magnestar.
The "lo" constant is a really huge number (unless, as you state the EM Drive happens to be located next to the field of a magnetar, which is certainly not the case, I might add, since the closest magnetar SGR 1806-20 is located about 50,000 light-years away from Earth ;) ).
PROOF:
Taking (from Eq. 39 in your paper)
b = (r1^2 - r2^2)/(4 (lo^2) Log[r2/r1])
Assuming r1 =<r2
Define
r1bar = r1 / lo
r2bar = r2 / lo
Then
b = (r1bar^2 - r2bar^2)/(4 Log[r2bar/r1bar])
Define:
r1bar = r2bar/c (where c >= 1 since r1bar =< r2bar )
bb = b / (r2bar^2)
then
bb = (1 - c^2)/(4 (c^2) Log[c])
Limit[bb, c -> 1] = - 0.5 (this corresponds to the maximum possible value of r1, r1 ~ r2 )
Limit[bb, c -> 1.5] = - 0.342542
Limit[bb, c -> 2] = - 0.270505
Limit[bb, c -> Infinity] = 0 (this corresponds to the minimum possible value of r1, r1 -> 0 )
Then it follows that the maximum absolute value of bb (bb= - 0.5) occurs at c = 1 , at r1 ~ r2
And to maximize b we must maximize r2bar, and therefore maximize r2, since b = bb (r2bar^2)= (- 1/2) (r2bar^2)
The proof for "a' is similar but it involves an extra step
Now, since the maximum (absolute magnitude) value of b is b = (- 1/2) (r2bar^2) and we know that
r2bar = r2 / lo
then the maximum value of b is
b = (- 1/2) ((r2 / lo)^2)
but since we know that lo is a huge number (unless the EM Drive is next to a magnestar) and feasible values of r2 are such that
r2 < lo
then it necessarily follows that the maximum possible value of b is much, much smaller than 1
b << 1
we conclude that the maximum possible values of b (and also a) are extremely small and hence they are negligible unless the EM Drive happens to be near a magnetar http://en.wikipedia.org/wiki/Magnetar.
(http://www.dailygalaxy.com/my_weblog/images/2008/09/25/magnetarfig3.jpg)
...Dear Marco,
Dear Jose,
Thanks a lot for spending some time on my calculations. You tried with b but did you check for a? Also l0 contains the density of energy of the electromagnetic field (the constant U0 squared). In any case, I am aware, as my colleagues, that general relativity could not be enough. My aim is to explore this approach to evaluate the magnitude of the effects in play. If such an effect would be confirmed by independent measurements at other NASA labs, as stated in the news, it would mean that we have to cope with something real new. It would be a great result. Otherwise, Baez and others will have reasons to laugh.
OK, yes, that's helpful to the people that have Mathematica. They can program that function ( notice that X'mn is not a buil-in function in Mathematica yet). To those that don't have Mathematica, that's the great usefulness of this link http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx: it gives X'mn to 15 digits accuracy and it is accessible to everyone.Thanks. That link ( https://www.wolframalpha.com/input/?i=besseljzero[1%2C1 ) only gives Xmn which are only useful for TM modes4) Also this link may be helpful, giving a table of the Xmn and X'mn to 15 digits accuracy
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
Try:
Wolfram alpha (https://www.wolframalpha.com/input/?i=besseljzero[1%2C1)
Is there a way that Wolfram Alpha can give X'mn which are needed for TE modes ?
I don't think so. But I believe you have Mathemagica:
http://www.me.rochester.edu/courses/ME201/webexamp/derbesszer.pdf - see ln67
The Kyoto (Japan) University link only goes to m=10, n=5 though, so if anyone knows of a link going to a higher quantum number (n > 5) , please post it, as it may be helpful to people just using Excel. (In case anyone is interested in investigating super-high mode shapes for n > 5 :)
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268
Interesting comments from Shawyer are attached:
Roger Shawyer, the British scientist who invented the highly controversial electromagnetic space propulsion technology called EmDrive, has said Nasa's work is encouraging but still far behind many private firms working on it already.
"Obviously I'm very happy for Nasa, they're having great fun, but it's not really real science," Shawyer told IBTimes UK in an exclusive interview.
"Obviously I'm very happy for Nasa, they're having great fun, but it's not really real science,"
Shawyer told IBTimes UK in an exclusive interview.
I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.
I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.
As usual, any comment is very welcome.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
Marco, your paper, after equation 39, has this interesting comment:Quote from: FrascaThese equations appear rather interesting as, by a proper choice of parameters, one can make a gravitational effect more or less relevant in the physics of the problem. It is the case to say that geometry comes to rescue.
Just what this "proper choice of parameters" is, it is not spelled out in your paper, so I will follow my interpretation of your equation.
It appears (see proof below) that in order to maximize the constants "a" and "b" in Equation 39, we want to have:
1) r1 as close as possible to r2
2) r2 as large as possible
Now, if this is correct, this is a rather peculiar, surprising geometry: it says that the axial length of the truncated cone should be close to zero while the radius should be as large as possible, in other words, the geometry should be as close to an almost perfect cylinder (small cone angle) with very short axial length, and with flat faces. In other words, this optimized geometry, according to Eq. 39 in your paper seems to be much closer to Cannae's device.
And it is actually not far from the geometry presently used by Dr. White. It is certainly not the geometry of a cone
(http://1.bp.blogspot.com/-2MORMyXf97o/VU4f2f8MtII/AAAAAAAA90w/Oc5eLpuujA4/s400/cannae_driveNASA.jpg)
However (see below), we also conclude that the maximum possible values of the constants b (and also a) are extremely small and hence they are negligible unless the EM Drive happens to be near a magnestar.
The "lo" constant is a really huge number (unless, as you state the EM Drive happens to be located next to the field of a magnetar, which is certainly not the case, I might add, since the closest magnetar SGR 1806-20 is located about 50,000 light-years away from Earth ;) ).
PROOF:
Taking (from Eq. 39 in your paper)
b = (r1^2 - r2^2)/(4 (lo^2) Log[r2/r1])
Assuming r1 =<r2
Define
r1bar = r1 / lo
r2bar = r2 / lo
Then
b = (r1bar^2 - r2bar^2)/(4 Log[r2bar/r1bar])
Define:
r1bar = r2bar/c (where c >= 1 since r1bar =< r2bar )
bb = b / (r2bar^2)
then
bb = (1 - c^2)/(4 (c^2) Log[c])
Limit[bb, c -> 1] = - 0.5 (this corresponds to the maximum possible value of r1, r1 ~ r2 )
Limit[bb, c -> 1.5] = - 0.342542
Limit[bb, c -> 2] = - 0.270505
Limit[bb, c -> Infinity] = 0 (this corresponds to the minimum possible value of r1, r1 -> 0 )
Then it follows that the maximum absolute value of bb (bb= - 0.5) occurs at c = 1 , at r1 ~ r2
And to maximize b we must maximize r2bar, and therefore maximize r2, since b = bb (r2bar^2)= (- 1/2) (r2bar^2)
The proof for "a' is similar but it involves an extra step
Now, since the maximum (absolute magnitude) value of b is b = (- 1/2) (r2bar^2) and we know that
r2bar = r2 / lo
then the maximum value of b is
b = (- 1/2) ((r2 / lo)^2)
but since we know that lo is a huge number (unless the EM Drive is next to a magnestar) and feasible values of r2 are such that
r2 < lo
then it necessarily follows that the maximum possible value of b is much, much smaller than 1
b << 1
we conclude that the maximum possible values of b (and also a) are extremely small and hence they are negligible unless the EM Drive happens to be near a magnetar http://en.wikipedia.org/wiki/Magnetar.
(http://www.dailygalaxy.com/my_weblog/images/2008/09/25/magnetarfig3.jpg)
I agree, this statement:Quote from: ibtimes ukhas said Nasa's work is encouraging but still far behind many private firms working on it already.
"Obviously I'm very happy for Nasa, they're having great fun, but it's not really real science,"
Shawyer told IBTimes UK in an exclusive interview.
is a very, very strange, not objective comment (for Shawyer to be quoted in http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141 as saying that "NASA is just having great fun, but the experiments at NASA are not really science" in Shawyer's opinion)
....
I have plotted with Maple the function bb(c)=(1-c^2)/(4*c^2*ln(c)) and I have found the figure I enclose. There is no maximum whatsoever. This curve has an asymptote at increasing c and another for c going to zero. This is what I meant saying that geometry comes to rescue. I am currently working out all this with Mathematica and I will update my draft as soon as possible with realistic values. Of course, my take remains the same as yours, if the effect exists Einstein theory could not be enough.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830617;image)
It's not a-priori. It's a-posteriori (http://en.wikipedia.org/wiki/A_priori_and_a_posteriori). We didn't know a-priori that it does not work. We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268
Interesting comments from Shawyer are attached:
Aside from such declarations, what I regret for is a dismissal a priori of an object really easy to test, with just few bucks.
At the time of cold fusion scientific community was much more open minded. Important labs tried to repeat the experiment with the help of Fleishmann himself.Scientific community's open mindedness towards a claim depends mainly to the claim itself.
Now, there are nor secrets neither patents at stake. It seems like we learnt to behave like Bellarmino at Galileo time where it was far too easy to look at the sky with the scope, but hard to admit to have been wrong and dismiss a lot of acquired "knowledge".How can you compare a person who received a grant from the British government to Galileo?
We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.
....
I have plotted with Maple the function bb(c)=(1-c^2)/(4*c^2*ln(c)) and I have found the figure I enclose. There is no maximum whatsoever. This curve has an asymptote at increasing c and another for c going to zero. This is what I meant saying that geometry comes to rescue. I am currently working out all this with Mathematica and I will update my draft as soon as possible with realistic values. Of course, my take remains the same as yours, if the effect exists Einstein theory could not be enough.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830617;image)
Take a gander at my proof http://forum.nasaspaceflight.com/index.php?topic=36313.msg1375279#msg1375279.
I had explicitly stated:
r1bar = r2bar/c (where c >= 1 since r1bar =< r2bar )
One has to assume that either r1 is smaller than r2 or that r2 is smaller than r1.
In your paper ( http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137 ) you assumed that r1 is smaller than r2, both in the integral and also in the expression showing the term (r2-r1)/h, in your equations 34 and 38 of your paper.
in order for r1 to be equal or less than r2, c must be equal to or greater than 1.
Instead you have plotted c for values smaller than 1.
Your plot shows values for c in the wrong range. c is defined to have values from 1 to Infinity, instead of from 0 to 1 as you plotted.
The values of c smaller than 1 you plotted are in conflict with the assumption that r1 is smaller than r2 (which was explicitly defined).
To be consistent with the assumption that r1 is smaller than r2, you should plot values of c equal to or greater than 1.
It's not a-priori. It's a-posteriori (http://en.wikipedia.org/wiki/A_priori_and_a_posteriori). We didn't know a-priori that it does not work. We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268
Interesting comments from Shawyer are attached:
Aside from such declarations, what I regret for is a dismissal a priori of an object really easy to test, with just few bucks.
Hence the knowledge that his drive does not work is a-posteriori knowledge. If his force was in low nano or pico newtons range, it would have been an a-priori assumption.QuoteAt the time of cold fusion scientific community was much more open minded. Important labs tried to repeat the experiment with the help of Fleishmann himself.Scientific community's open mindedness towards a claim depends mainly to the claim itself.QuoteNow, there are nor secrets neither patents at stake. It seems like we learnt to behave like Bellarmino at Galileo time where it was far too easy to look at the sky with the scope, but hard to admit to have been wrong and dismiss a lot of acquired "knowledge".How can you compare a person who received a grant from the British government to Galileo?
....Sorry, but we cannot have a logical, mathematical discussion where you first write equations where r1 is assumed to be less than r2 (as Eq. 34 and 38 of your paper) and now you proceed to show a graph with a range of variables in conflict with YOUR assumption that r1 was smaller than r2. That is inconsistent. Incorrect results follow from inconsistencies in formulation.
Your assumption is not needed as this function retains his sign independently on your choice. In any case, there are not extrema and this function runs to zero on the right and runs to minus infinity on the left. You can verify yourself that the function is symmetric under the exchange r1<->r2.
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimension<M
....Sorry, but you cannot consistently first write equations where r1 is assumed to be less than r2 (as per your paper) and now proceed to show a graph in conflict with YOUR assumption that r1 was smaller than r2. That is inconsistent. Incorrect results follow from inconsistencies in formulation.
Your assumption is not needed as this function retains his sign independently on your choice. In any case, there are not extrema and this function runs to zero on the right and runs to minus infinity on the left. You can verify yourself that the function is symmetric under the exchange r1<->r2.
I suggest that you:
1) make a plot of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates
2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.
Further discussion without you clearly defining your geometrical variables is moot and can lead nowhere, as your paper assumes r1 <r2 and now you show plots for r1 > r2, in strong conflict with your assumed geometry and equations
:)
....Marco,
Jose,
I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
....Marco,
Jose,
I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
Please
1) make a plot (you can sketch the geometry by hand with pencil and paper, scan it and post the image :) ) of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates
2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.
and then we can continue :)
2/c, which is 6.6 uN/kW , times 50 000 , is 0.33 N/kW . Multiply by the bound on EM exchanging momentum with something unknown, a very small force (nanoNewtons). edit: typo.We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.
We also know that a high Q cavity of say 50,000 will do 50,000 bounces of the em field, each adding to the generated force. Shawyer's Force equation of (2 Po Df Q) / c clearly states Q is the way the EM Drive multiplies the very low force of one way to a much higher value.
Same effect used with laser thruster:
http://en.wikipedia.org/wiki/Photonic_laser_thruster
...There is no claim to support here. It is also difficult for me to understand what you believe to have proven. There is no error there and you can do any computation you like with that. This is a real wasting of time.
....Marco,
Jose,
I am not arguing against my paper. You know may take. I am questioning your proof based on a functional form that has the mathematical properties I have shown. I know by myself, and I stated it in the draft, that here we are working with really small values. As you can see, I have not attempted any computation of a force, if any, or thrust. I am thinking about this and I am trying to work with real values. But please note also that this is a function of three independent variables: r1, r2 and U0.
Please
1) make a plot (you can sketch the geometry by hand with pencil and paper, scan it and post the image :) ) of the geometry of the truncated cone you have in mind: clearly showing what you define to be r1, r2, h, and the z and r coordinates
2) explicitly show what is the optimal geometry of the truncated cone, as per your paper.
and then we can continue :)
I think you are completely off the target. What the heck we have to continue? You can choice r2>r1 and live happily with that or the other way around. Choose what you prefer and keep it. There is no claim to support here. It is also difficult for me to understand what you believe to have proven. There is no error there and you can do any computation you like with that. This is a real wasting of time.
Marco,
1) You wrote a very interesting paper, concluding that there is a geometry (I presume an optimal geometry) of a truncated cone that "comes to the rescue" which I assume it to mean that maximizes the General Relatvity effect in this cavity.
2) My proof, based on your paper shows that that optimal geometry is a cylinder with flat faces and negligible axial length. The optimal geometry according to the equations in your paper being much closer to the Cannae cavity and the pillbox shape used by Dr. White than the geometry of a conical cavity.
3) What is the actual optimal geometry of the cavity to maximize the GR effect, according to your paper? I think that for you showing what is this optimal geometry would be great conclusion to your interesting paper.
...
But this is exactly what I am doing now to update my draft. Mathematica is running computing a realistic k with the values r1 and r2 taken from Minotti's paper. I need to estimate U0. In a few days I can give an answer to your question.
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimension<M
The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.
...
But this is exactly what I am doing now to update my draft. Mathematica is running computing a realistic k with the values r1 and r2 taken from Minotti's paper. I need to estimate U0. In a few days I can give an answer to your question.
Suggestion: to use the geometrical values used by Greg Egan r1=2.5 cm, r2=10 cm, θw = 20° here: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html as Minotti quotes Egan's equations in Minotti's paper, and Egan shows explicit field solutions and the energy for those geometrical parameters.
2/c, which is 6.6 uN/kW , times 50 000 , is 0.33 N/kW . Multiply by the bound on EM exchanging momentum with something unknown, a very small force (nanoNewtons). edit: typo.We know from direct measurements that EM fields behave in a specific manner, down to parts per trillion. Momentum which is carried by an electromagnetic field can be measured directly as the field strength, with far greater precision. This knowledge puts a very low upper bound on the net momentum that EM fields can acquire and exchange with the cavity.
We also know that a high Q cavity of say 50,000 will do 50,000 bounces of the em field, each adding to the generated force. Shawyer's Force equation of (2 Po Df Q) / c clearly states Q is the way the EM Drive multiplies the very low force of one way to a much higher value.
Same effect used with laser thruster:
http://en.wikipedia.org/wiki/Photonic_laser_thruster
....Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.
Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
....Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.
Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
See http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html where Greg Egan shows that the stresses on the inner conical surfaces are not negligible: following Maxwell's equations they exactly balance out the stresses on the spherical faces to end with zero net force on the EM Drive.
Did Shawyer publish a paper answering in detail the objections raised by Greg Egan's ?
....Greg Egan first considered the spherical ends, as a response to Shawyer's article with flat faces in the New Scientist article.
Shawyer did say the wave slides up and down the cavity walls and exerts no significant force on it. From this diagram, that seems to be the case. It does slide up and down the cavity walls, while always being at a right angle to it.
...
See http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html where Greg Egan shows that the stresses on the inner conical surfaces are not negligible: following Maxwell's equations they exactly balance out the stresses on the spherical faces to end with zero net force on the EM Drive.
Did Shawyer publish a paper answering in detail the objections raised by Greg Egan's ?
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimension<M
The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.
It's being reflected off the wall, why do you think it wouldn't generate a force orthogonally to the wall? I know it doesn't look like it's being reflected off the wall, but it has to be otherwise it would simply go through the wall....Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
You cannot stare at a pictorial representation claiming something is there. Physics means mathematics and mathematics, through Maxwell equations, says no net momentum.
I just want to throw this up here:
http://www.nature.com/ncomms/2014/140306/ncomms4300/full/ncomms4300.html (http://www.nature.com/ncomms/2014/140306/ncomms4300/full/ncomms4300.html)
http://arxiv.org/ftp/arxiv/papers/1308/1308.0547.pdf (http://arxiv.org/ftp/arxiv/papers/1308/1308.0547.pdf)
I think if you're looking in classical physics for answers, you won't find them.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.
What is your understanding of how an EM wave, acting at right angles to the cavity wall, can exert any force on it?
I assume the result would be zero, except for eddy current losses and as the cavity has a Q of 50,000, those losses are very small and are not involved in thrust generation.
It's being reflected off the wall, why do you think it wouldn't generate a force orthogonally to the wall? I know it doesn't look like it's being reflected off the wall, but it has to be otherwise it would simply go through the wall....Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
By the third principle, there is a movement of the cavity compensating the hit of the wave. It is the same that happens when you push on the steering wheel to move your car from inside. Your car stands still.
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.
What is your understanding of how an EM wave, acting at right angles to the cavity wall, can exert any force on it?
I assume the result would be zero, except for eddy current losses and as the cavity has a Q of 50,000, those losses are very small and are not involved in thrust generation.
By the third principle, there is a movement of the cavity compensating the hit of the wave. It is the same that happens when you push on the steering wheel to move your car from inside. Your car stands still.
I'm working on a Ruby script that builds a Sketchup model of Sawyer's drive according to the equations and concepts being generated by this group. So as work proceeds a few questions have come up.
Most of these questions refer to the recently posted photo of Sawyer's drive.
1. What possible material is the large end plate made of?
It appears to be aluminum. One purpose of the o-ring is therefore to prevent galvanic corrosion. This also means the bolts are made of the same metal and they do appear to be the same color/luster and are seated in rubber grommets.
2. Why a different metal?
A possible answer (see question 4) is that it is far easier to put a curve in an aluminum blank (at least for me it is) than in copper (cheaper and lighter in weight as well).
3. What possible material is the small end plate made of?
It appears to be copper - yet has aluminum looking bolts also seated in grommets!
4. Do we know with fair certainty that the end plates have a spherical curve?
This might explain why the large end plate is so thick - it is much like a telescope mirror. It needs thickness to accommodate the curvature and provides rigidity. The outside of the large plate appears to be flat to me and I see no reason for a curve there.
5. What are people's thoughts on the plates being silvered on the curved surfaces?
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
I'm working on a Ruby script that builds a Sketchup model of Sawyer's drive according to the equations and concepts being generated by this group. So as work proceeds a few questions have come up.
Most of these questions refer to the recently posted photo of Sawyer's drive.
1. What possible material is the large end plate made of?
It appears to be aluminum. One purpose of the o-ring is therefore to prevent galvanic corrosion. This also means the bolts are made of the same metal and they do appear to be the same color/luster and are seated in rubber grommets.
2. Why a different metal?
A possible answer (see question 4) is that it is far easier to put a curve in an aluminum blank (at least for me it is) than in copper (cheaper and lighter in weight as well).
3. What possible material is the small end plate made of?
It appears to be copper - yet has aluminum looking bolts also seated in grommets!
4. Do we know with fair certainty that the end plates have a spherical curve?
This might explain why the large end plate is so thick - it is much like a telescope mirror. It needs thickness to accommodate the curvature and provides rigidity. The outside of the large plate appears to be flat to me and I see no reason for a curve there.
5. What are people's thoughts on the plates being silvered on the curved surfaces?
Assume copper spherical end caps.
Hard to see a Q of 50,000 to 60,000 with flat end plates.
End caps are not necessarily the frustum EM wave bounce end plates.
End caps may just be to provide pressure seal and sandwich end plates between cavity flange and the external end plates.
Also believe the bottom end cap is so think as it has to allow the big end curve to exist. Also note the big end cap is not sitting flush on the alum beam. It may have a convex curve or maybe other big end sense ports are down there as shown in the 2nd attachment.
Bolts are probably space grade stainless. Should be no H20 in a satellite so no galvanic action. I'm not a sat guy, so just my guestimation.
Once you know the frustum vertex you can work out the end plate radii from this:
...Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
If the walls are perfectly conducting, the NET will be zero, but they are not perfectly conducting and these are transverse waves. The electric field parallel to the wall may be zero but the field perpendicular is not. It attracts/repels electrons in the metal, driving currents. Also, magnetic permeability of copper is very low and conductivity is very high, so the rapidly changing magnetic field also drive currents. This is "work" being done on the walls of the cone.
Likewise, as work is done by the waves, the waves lose energy and decay to longer wavelengths. Giving up momentum to the Frustum, asymmetrically. As the waves are heading toward the small end, the guide wavelength eventually becomes imaginary and so the waves decay much faster. What Maxwell's equations and Greg Egan show is that the reflected waves that generate standing waves, play no part in the thrust, and they're right.
Todd
Yep on the galvanic corrosion.
Yes. Correct. Understand eddy current losses.Yes, that's a more complete description. 100% concur.
A Q of 50,000 say it takes 50,000 up and back cycles to drain off all the energy in the EM wave into wall eddy current losses and increased cavity wall temperature. The Chinese did measure and report on this as attached.
Due to the side wall cosine angle to the EM wave, there is no resultant radiation pressure on the side walls.
Yep on the galvanic corrosion.
Galvanic corrosion occurs in space? Doesn't there needs to be an electrolyte between the different metals for it to happen? Thought spacecraft were ultra clean?
Your wave inside and outside the waveguide is merely a sum of what you have if the wall did not exist and what is radiated by the wall.It's being reflected off the wall, why do you think it wouldn't generate a force orthogonally to the wall? I know it doesn't look like it's being reflected off the wall, but it has to be otherwise it would simply go through the wall....Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan. Instead, Greg Egan showed again, a known-proof that the stresses on the inner walls of a resonating cavity of any arbitrary shape whatsoever (as long as it is closed) perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
If you can, please answer my simple question:
How can a curved EM wave, as in the attachment, touching the cavity wall at right angles to the wall, cause any force to be generated on the wall?
It is not reflection off the wall any more than it would in free space if the walls did not exist. All the altering frustum diameter does is to alter the guide wavelength and the group velocity based on the cutoff frequency. There is no side wall bounce involved here.
For fear of stating the obvious:At the surface of a perfectly reflective light sail, E is orthogonal to the sail and E x H is parallel to the sail, which merely means that there's nothing being absorbed, not that there's no force.
With appropriately curved internal endplates, as TheTraveller has drawn, the Poynting vector is precisely parallel to the side walls at all locations along the side walls, at all times. Ergo zero thrust on the side walls anywhere, at any time. Another way this is expressed is in the maths of light sail thrust (see any of Geoff Landis's papers for example). The thrust goes as the cosine of the angle made by the Poynting vector with the surface normal. Thus in this case that angle is a right angle so the cosine is zero so the thrust is zero.
Yep on the galvanic corrosion.
Galvanic corrosion occurs in space? Doesn't there needs to be an electrolyte between the different metals for it to happen? Thought spacecraft were ultra clean?
Yep, as in I agree about there being none.
Yep on the galvanic corrosion.
Galvanic corrosion occurs in space? Doesn't there needs to be an electrolyte between the different metals for it to happen? Thought spacecraft were ultra clean?
Yep, as in I agree about there being none.
Though that might be the original reason. I think the drive is several years from heading to space and he would want to be able to disassemble/reassemble in the near term.
I have been meaning to ask. If anyone gets the chance to test this out for me I would be fascinated to hear the results. It's a dual cavity experiment. I think it would require a klystron or twt with a continuous phase. Cylindrical cavities should work. They would need to have a gap between the two of them of 1/4 lambda wavelength with their phase out of alignment by 90 degrees or pi/2 radians.
What should happen is the plate of cavity 1 should have circulating current stimulated by the radiation inside that builds up depending on the Q of the cavity. Information is limited by the speed of light so that appearance of current should be on its way to the next cavity which has its current out of phase by 90 degrees. When the information reaches cavity 2 the current in cavity 2 should appear to be moving with cavity 1 so it is attracted. Cavity 1 on the other hand when the signal reaches it appears to have its current moving against cavity 2 and should be repulsed (similar to current in wires). I would guess this effect should also scale with the Q of the cavity.
It may be possible for a dielectric to slow the information transfer between the cavities and move them closer together and increase the effect. I would guess some radiation may tunnel through the cavities into the other one and attenuation of one cavity may be required to keep them equal in amplitude and out of phase by 90 degrees.
My guess is it should be similar to attraction between magnets but the force is in the same direction for both cavities. Images attached for ease of understanding.
Fig1 Simple.png key:
1. Forces
2. Current
3. Current
4. Appearance of current limited by the speed of light (bottom wire)
5. Appearance of current limited by the speed of light (top wire)
8, 9, 10, 11 are frames of current over time. Frame 12 is a repeat of frame 8 and frame 13 is a repeat of 9. (Only 4 frames needed). The illustration of force between wires can parallel to the cavity plate I think.
Thanks!
If the walls are perfectly conducting, the NET will be zero, but they are not perfectly conducting and these are transverse waves. The electric field parallel to the wall may be zero but the field perpendicular is not. It attracts/repels electrons in the metal, driving currents. Also, magnetic permeability of copper is very low and conductivity is very high, so the rapidly changing magnetic field also drive currents. This is "work" being done on the walls of the cone.
Likewise, as work is done by the waves, the waves lose energy and decay to longer wavelengths. Giving up momentum to the Frustum, asymmetrically. As the waves are heading toward the small end, the guide wavelength eventually becomes imaginary and so the waves decay much faster. What Maxwell's equations and Greg Egan show is that the reflected waves that generate standing waves, play no part in the thrust, and they're right.
Todd
Yes. Correct. Understand eddy current losses.
A Q of 50,000 say it takes 50,000 up and back cycles to drain off all the energy in the EM wave into wall eddy current losses and increased cavity wall temperature. The Chinese did measure and report on this as attached.
Due to the side wall cosine angle to the EM wave, there is no resultant radiation pressure on the side walls.
With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
If the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
You're ignoring diffraction. If the frustum side walls were not there, the radiation would leak out.With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
Last line say it all:QuoteIf the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
The effective radiation source is the vertex of the frustum. The frustum side wall are aligned to, pointing at the vertex. Therefore the radiant pressures on the side walls are zero.
Let's say your hitting the steering wheel very fast again and again and let's leave out it was someone who cut you off in traffic. Lets say each time you brought your hand back it gained energy in the action of the backward movement , it was from let's say a quantum/force which has no relation or attachment to the car but into the underlying quantum world (weird and neat stuff), then each time you would strike the wheel you would impart force and momentum to the car. Off you go. Not so much with a flashlight on the windshield as light is a little different in it's construction and it would piss off the car in front of you but that's another story....Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.
What is your understanding of how an EM wave, acting at right angles to the cavity wall, can exert any force on it?
I assume the result would be zero, except for eddy current losses and as the cavity has a Q of 50,000, those losses are very small and are not involved in thrust generation.
By the third principle, there is a movement of the cavity compensating the hit of the wave. It is the same that happens when you push on the steering wheel to move your car from inside. Your car stands still.
Then, unless this force and momentum is very small, the mechanics of motion of a hand through space would have to differ from what was observed in high precision experiments that did not involve cars.Let's say your hitting the steering wheel very fast again and again and let's leave out it was someone who cut you off in traffic. Lets say each time you brought your hand back it gained energy in the action of the backward movement , it was from let's say a quantum/force which has no relation or attachment to the car but into the underlying quantum world (weird and neat stuff), then each time you would strike the wheel you would impart force and momentum to the car. Off you go. Not so much with a flashlight on the windshield as light is a little different in it's construction and it would piss off the car in front of you but that's another story....Greg Egan did not claim that the EM Drive cannot work because of a theory invented by Greg Egan.
Shawyer published this measured thrust as did the Chinese and why they think it does what it does. Someone who publishes a paper claiming it can't work because of their theory, just might be politely ignored as they get on with business.
It is not his theory. Greg Egan is showing again a well-known result.
Instead, Greg Egan showed again, an already known-proof that the stresses due to standing waves on the inner walls of a resonating cavity of any arbitrary shape whatsoever perfectly balance, and therefore there is zero net force in any direction, according to Maxwell's equations.
Egan exploited the computations of what the community only stated: Momentum is not conserved and so this does not work. This is the reason why we are looking elsewhere than only Maxwell equations.
What is your understanding of how an EM wave, acting at right angles to the cavity wall, can exert any force on it?
I assume the result would be zero, except for eddy current losses and as the cavity has a Q of 50,000, those losses are very small and are not involved in thrust generation.
By the third principle, there is a movement of the cavity compensating the hit of the wave. It is the same that happens when you push on the steering wheel to move your car from inside. Your car stands still.
Shell
Yep on the galvanic corrosion.
Galvanic corrosion occurs in space? Doesn't there needs to be an electrolyte between the different metals for it to happen? Thought spacecraft were ultra clean?
Yep, as in I agree about there being none.
Though that might be the original reason. I think the drive is several years from heading to space and he would want to be able to disassemble/reassemble in the near term.
I assume this is the final product that SPR shipped to Boeing. Has been plated and I'm sure other issues addressed and fixed. Also suggest the photo was distorted to make it harder to work out the dimensions.
On a NASA EW slide, this unit was labeled a "High Fidelity Test Article".
You're ignoring diffraction. If the frustum side walls were not there, the radiation would leak out.With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
Last line say it all:QuoteIf the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
The effective radiation source is the vertex of the frustum. The frustum side wall are aligned to, pointing at the vertex. Therefore the radiant pressures on the side walls are zero.
edit: write an equation of form E(position, time) and H(position, time) . Maybe it would be clearer for a cylinder with flat end pieces? You can't just take geometric optics approximation from Wikipedia and apply it to microwaves in a reasonable sized cavity... it won't be correct then.
Yes, that version has a bunch of improvements over the copper version.As I showed about a hundred pages ago, building a 3D model based upon photographs requires adjustments to compensate the camera lens distortions. Unless you have the specific data of the camera and its lens, it will be impossible to accurately build a 3D model. At best you'll have an approximation.
Building it in SketchUp really highlights issues that would come upduring construction. I have had this photo and really should have been going off of it. I am not trying to guess dimensions from the photos but instead are using the equations and dimensions in this forum. The script currently takes 3 parameters and generates the model from that.
Yep on the galvanic corrosion.
Galvanic corrosion occurs in space? Doesn't there needs to be an electrolyte between the different metals for it to happen? Thought spacecraft were ultra clean?
Yep, as in I agree about there being none.
Though that might be the original reason. I think the drive is several years from heading to space and he would want to be able to disassemble/reassemble in the near term.
I assume this is the final product that SPR shipped to Boeing. Has been plated and I'm sure other issues addressed and fixed. Also suggest the photo was distorted to make it harder to work out the dimensions.
On a NASA EW slide, this unit was labeled a "High Fidelity Test Article".
If I want to maximize the Q of a cavity I would silver plate the copper, and if I wanted maximum repeatablity I would gold flash the silver.
The cinder blocks in the wall should be 8" high. The rf connector with the cap on it looks to be a type SMA and not N, iirc the SMA flange connectors are about .5" square.
It's a geometric optics approximation. Doesn't hold precisely.You're ignoring diffraction. If the frustum side walls were not there, the radiation would leak out.With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
Last line say it all:QuoteIf the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
The effective radiation source is the vertex of the frustum. The frustum side wall are aligned to, pointing at the vertex. Therefore the radiant pressures on the side walls are zero.
edit: write an equation of form E(position, time) and H(position, time) . Maybe it would be clearer for a cylinder with flat end pieces? You can't just take geometric optics approximation from Wikipedia and apply it to microwaves in a reasonable sized cavity... it won't be correct then.
We were discussing radiation pressure generated from EM waves according to Maxwell's equations (attached). This pressure is apparently subject to cosine angle loss and thus when the EM wave moves along the frustum side walls and is not bouncing off the frustum spherical end plates, there is no Maxwell radiation pressure generated on the frustum side walls.
Or did I not understand what the cosine loss factor is for in the lower of the 2 equations?
Yes, that version has a bunch of improvements over the copper version.As I showed about a hundred pages ago, building a 3D model based upon photographs requires adjustments to compensate the camera lens distortions. Unless you have the specific data of the camera and its lens, it will be impossible to accurately build a 3D model. At best you'll have an approximation.
Building it in SketchUp really highlights issues that would come upduring construction. I have had this photo and really should have been going off of it. I am not trying to guess dimensions from the photos but instead are using the equations and dimensions in this forum. The script currently takes 3 parameters and generates the model from that.
Do not underestimate the distortion caused by targeting under the horizon line. They are important and increase when using a wide angle lens. When targeting under the horizon, the lens distortions cause vertical lines to focus on a point below, making the top of the frustum appear larger to the bottom plate.
I did stop a further image analysis on the alu frustum because somebody found the exact dimensions of the frustum, as it appears to be an industrial manufactured piping part. It is readily available to everybody...There was no need anymore for an estimate on that frustum...
I'll try to dig it up... it's somewhere inhere, i suspect in the first 50 pages...
...
Dear Jose,
Thanks a lot for spending some time on my calculations. You tried with b but did you check for a?...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
It's a geometric optics approximation. Doesn't hold precisely.You're ignoring diffraction. If the frustum side walls were not there, the radiation would leak out.With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
Last line say it all:QuoteIf the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
The effective radiation source is the vertex of the frustum. The frustum side wall are aligned to, pointing at the vertex. Therefore the radiant pressures on the side walls are zero.
edit: write an equation of form E(position, time) and H(position, time) . Maybe it would be clearer for a cylinder with flat end pieces? You can't just take geometric optics approximation from Wikipedia and apply it to microwaves in a reasonable sized cavity... it won't be correct then.
We were discussing radiation pressure generated from EM waves according to Maxwell's equations (attached). This pressure is apparently subject to cosine angle loss and thus when the EM wave moves along the frustum side walls and is not bouncing off the frustum spherical end plates, there is no Maxwell radiation pressure generated on the frustum side walls.
Or did I not understand what the cosine loss factor is for in the lower of the 2 equations?
For example suppose you got a beam of coherent light, 5mm across, 500nm wavelength, in space. It's not going all parallel to it's original direction, it's spreading, to about 1m across at 10 000m from the source (Makes a fuzzy "Airy disk" pattern).
edit: The Poynting vector on the sides of a perfect cylinder over this beam, is not parallel to the axis. It's this Poynting vector that matters.
...
Dear Jose,
Thanks a lot for spending some time on my calculations. You tried with b but did you check for a?...
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
Here are the expressions including both a and b, to give a value to L
Assuming r1 =<r2
as per the geometry in the following image
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
Taking (from Eq. 39 in your paper)
b = (r1^2 - r2^2)/(4 (lo^2) Log[r2/r1])
Define
r1bar = r1 / lo
r2bar = r2 / lo
Then
b = (r1bar^2 - r2bar^2)/(4 Log[r2bar/r1bar])
Define:
r1bar = r2bar/c (where c >= 1 since r1bar =< r2bar )
bb = b / (r2bar^2)
then
bb = - cc/4
where
cc = (c^2 - 1)/( (c^2) Log[c])
and
b = - ( (r2bar^2) /4 ) *cc
Taking (from Eq. 39 in your paper)
a = (1/Log[r2/r1]) (1/(4*(lo^2)))*((r2^2)*Log[r1/lo] - (r1^2)*Log[r2/lo])
then
a = (1/Log[r2bar / r1bar]) (1/4)*((r2bar^2)*Log[r1bar] - (r1bar ^2)*Log[r2bar])
a = ( (r2bar^2) /4 ) * (Log[r2bar] *cc - 1 )
and we obtain
L = a + b Log[rbar] + (rbar^2) / 4
substituting the expressions for a and b
L = ( (r2bar^2)/4 ) * (Log[r2bar] *cc - 1 ) - ( (r2bar^2)/4) *cc * Log[rbar] + (rbar^2)/4
L = (r2bar^2)/4)*cc*( Log[r2bar] - Log[rbar]) - (r2bar^2 - rbar^2)/4
Limit[cc, c -> 1] = 2 (this corresponds to the maximum possible value of r1, r1 ~ r2 )
Limit[cc, c -> Infinity] = 0 (this corresponds to the minimum possible value of r1, r1 -> 0 )
so for c -> 1, r1 ~ r2
L = (r2bar^2)/2)( Log[r2bar] - Log[rbar]) - (r2bar^2 - rbar^2)/4
and for c -> Infinity, r1 -> 0
L = - (r2bar^2 - rbar^2)/4
Since
rbar =< r2bar (all material points must be at a radius vector r smaller than or equal to r2)
We want to maximize the following quantity:
( (r2bar^2) /4 ) * (Log[r2bar] *cc
which means that we must have maximum cc
Maximum cc occurs for
Limit[cc, c -> 1] = 2 (this corresponds to the maximum possible value of r1, r1 ~ r2 )
Therefore, for a maximum L we want to have:
r1 as close as possible to r2
This says that the axial length of the truncated cone should be close to zero.In other words, this optimized geometry, according to Eq. 39 in your paper seems to be much closer to Cannae's device.
And it is actually not far from the geometry presently used by Dr. White. It is certainly not the geometry of a pointy cone
(http://1.bp.blogspot.com/-2MORMyXf97o/VU4f2f8MtII/AAAAAAAA90w/Oc5eLpuujA4/s400/cannae_driveNASA.jpg)
As you said, the "lo" constant is a really huge number, unless the EM Drive happens to be near a magnestar.
This means that the variable ((r2/lo)^2) is very small.
---->However, it get multiplied by Log[ r2/lo] which can be an even larger negative number<----
To be more specific, we need a number for lo, so that we can calculate the term (r2bar^2)/2)( Log[r2bar] - Log[rbar]) in
L = (r2bar^2)/2)( Log[r2bar] - Log[rbar]) - (r2bar^2 - rbar^2)/4
(The above expression is for r1~r2, such that c~1 and cc~2)
:)
NOTE: while the condition r1~r2 (r1 as close as possible to r2) still holds (since the smaller r1 with respect to r2 the smaller the term cc), notice that I removed a condition on r2 that I had previously stated. This is because while to maximize the term (r2bar^2)/2) we also want r2 as large as possible, to maximize (-Log[r2bar]) one wants r2 as small as possible. So to be specific one needs a number for lo.
@RODALThanks. But where does the frequency enter into the equation for L? all I see is a, b, r2bar, r1bar, lo geometrical parameters. It seems that the electromagnetic field Power only enters through the parameter (Uo)2 which is built inside the length "lo", so as we said, we need a number for "lo" to make any more progress.
It seems (to me) that that is quite correct, but that does not mean that that is for max force since it neglects frequency. I can see how that might be for max laser sideband generation w/o constraining the frequency. (ie very high radial modes)
See Marco's Eq. 19, 20 and 28 in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
@RODALThanks. But where does the frequency enter into the equation for L? all I see is a, b, r2bar, r1bar, lo geometrical parameters. It seems that the electromagnetic field Power only enters through the parameter (Uo)2 which is built inside the length "lo", so as we said, we need a number for "lo" to make any more progress.
It seems (to me) that that is quite correct, but that does not mean that that is for max force since it neglects frequency. I can see how that might be for max laser sideband generation w/o constraining the frequency. (ie very high radial modes)
See Marco's Eq. 19, 20 and 28 in http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830137
It is the choice of the resonant mode that fixes l0 and this depends on frequency (indirectly). You should check Egan link for some numbers to put in.
Which only happens thanks to the reflection off the sides.It's a geometric optics approximation. Doesn't hold precisely.You're ignoring diffraction. If the frustum side walls were not there, the radiation would leak out.With regards to the forces on the side of the cavity, all I can say is, write the field equations for your fields (what is the H and E at a given point in space), then I can calculate the forces on the boundaries and/or show that your fields violate Maxwell's equations. When it is a picture I don't know what exactly you're talking about.
Last line say it all:QuoteIf the absorbing surface is planar at an angle a to the radiation source, the intensity across the surface will be reduced.
The effective radiation source is the vertex of the frustum. The frustum side wall are aligned to, pointing at the vertex. Therefore the radiant pressures on the side walls are zero.
edit: write an equation of form E(position, time) and H(position, time) . Maybe it would be clearer for a cylinder with flat end pieces? You can't just take geometric optics approximation from Wikipedia and apply it to microwaves in a reasonable sized cavity... it won't be correct then.
We were discussing radiation pressure generated from EM waves according to Maxwell's equations (attached). This pressure is apparently subject to cosine angle loss and thus when the EM wave moves along the frustum side walls and is not bouncing off the frustum spherical end plates, there is no Maxwell radiation pressure generated on the frustum side walls.
Or did I not understand what the cosine loss factor is for in the lower of the 2 equations?
For example suppose you got a beam of coherent light, 5mm across, 500nm wavelength, in space. It's not going all parallel to it's original direction, it's spreading, to about 1m across at 10 000m from the source (Makes a fuzzy "Airy disk" pattern).
edit: The Poynting vector on the sides of a perfect cylinder over this beam, is not parallel to the axis. It's this Poynting vector that matters.
Built and used many optical telescopes, including a 12 inch, Schmidt Cassegrain. Diffraction and I got to be good enemies.
There is no natural spread for the beam inside the cavity. It is controlled by the guide and cutoff wavelengths determined by the cavity diameter it travels through
and by bouncing off the spherical end plates, which as I see it orient the EM waves so they travel / slide along the side walls at a 0 bounce radiant cosine angle.What this boils down to, is that if you actually specify the E and H, not with a picture but with equations (note that you can't have a spherically symmetrical wave with EM fields, because it doesn't work like a pressure wave), it will be possible to either show that 1: Maxwell's equations don't hold for E and H, or 2: there is a force on the walls.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
https://youtu.be/Rbf7735o3hQ
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Test 03 Success. I have thrust.Beware of buoyancy, thermal expansion of cables, magnetic forces on cables, vibration, etc etc. Also, most importantly, safety: you got high voltage and microwaves that can really damage your eyes (so don't be closer than a couple meters from it when it is on). Unless you get the same thrust upwards as downwards down to, say, 5% , with less than 5% of the thrust if you mount it sideways, without excessive fiddling and adjustments, I would just describe it as a deflection rather than thrust. Thrust is a hypothesis, and an experimenter should be impartial towards hypotheses. Essentially without tests sideways (so the weight change is zero) and upside down, it is less rigorous than soft sciences (which nowadays employ controls).
I modified the setup and now i weight the frustum. the precision is much better.
https://youtu.be/Rbf7735o3hQ
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
https://youtu.be/Rbf7735o3hQ
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Do you have the weight of the setup, so that we can calculate the newtons of thrust from this?
....
Dear Jose,
Thank you a lot for your effort to this question. Also thanks to @notsureofit for his help. You are right. I have checked this with Maple and optimized the function L(r) as a function of r1, r2 and U0 also. And yes, r1=r2 is the solution! I have other checks to do and my notebook just keeps on freezing for a computation of these but I hope to complete all in a few days.
This means that Harold White experiments could represent a great leap beyond in experimental general relativity. This was my initial hope. As a theoretical physicist please don't ask me about applications!
Give me a few days for further checks and I will update my draft, with due acknowledgements.
Regards.
Test 03 Success. I have thrust.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
https://youtu.be/Rbf7735o3hQ
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Test 03 Success. I have thrust.
I'm new to this thread, but doesn't Shawyer's theory paper say that it is supposed to be Big-Endian? That is, that a larger force is applied on the inner face of the big end than on the inner face of the small end, so that if it were flying free in space it would accelerate big end first?
Is Iulian's Little-Endian negative reading consistent with other theory or experimental results?
~Kirk
Test 03 Success. I have thrust.
I'm new to this thread, but doesn't Shawyer's theory paper say that it is supposed to be Big-Endian? That is, that a larger force is applied on the inner face of the big end than on the inner face of the small end, so that if it were flying free in space it would accelerate big end first?
Is Iulian's Little-Endian negative reading consistent with other theory or experimental results?
~Kirk
Watch Shawyers dynamic test.
http://emdrive.com/dynamictests.html
Moves toward small end. So both tests generate device movement in the same direction. Toward the small end.
Test 03 Success. I have thrust.
I'm new to this thread, but doesn't Shawyer's theory paper say that it is supposed to be Big-Endian? That is, that a larger force is applied on the inner face of the big end than on the inner face of the small end, so that if it were flying free in space it would accelerate big end first?
Is Iulian's Little-Endian negative reading consistent with other theory or experimental results?
~Kirk
Watch Shawyers dynamic test.
http://emdrive.com/dynamictests.html
Moves toward small end. So both tests generate device movement in the same direction. Toward the small end.
Also interesting, and just to remind folks, it appears that Iulian has the waveguide directly inside the fulstrum ending some what near the centre of the cavity. Sawyer, et al all seemed to use an antenna of some type that was close to one side of the cavity.
Test 03 Success. I have thrust.
I'm new to this thread, but doesn't Shawyer's theory paper say that it is supposed to be Big-Endian? That is, that a larger force is applied on the inner face of the big end than on the inner face of the small end, so that if it were flying free in space it would accelerate big end first?
Is Iulian's Little-Endian negative reading consistent with other theory or experimental results?
~Kirk
Test 03 Success. I have thrust.
I'm new to this thread, but doesn't Shawyer's theory paper say that it is supposed to be Big-Endian? That is, that a larger force is applied on the inner face of the big end than on the inner face of the small end, so that if it were flying free in space it would accelerate big end first?
Is Iulian's Little-Endian negative reading consistent with other theory or experimental results?
~Kirk
Watch Shawyers dynamic test.
http://emdrive.com/dynamictests.html
Moves toward small end. So both tests generate device movement in the same direction. Toward the small end.
Also interesting, and just to remind folks, it appears that Iulian has the waveguide directly inside the fulstrum ending some what near the centre of the cavity. Sawyer, et al all seemed to use an antenna of some type that was close to one side of the cavity.
In the 1st EM Drive device, Shawyer fed the microwaves in via a short waveguide to around the centre of the frustum. You can see the wave guide at the rear of the frustum.
In the next Demonstration EM Drive, the magnetron generated microwaves were fed into the frustum at a point near the big end as can be seen in these 2 last images.
The 3rd device, the Flight Thruster, used a coax Rf feed at near the big end.
So it would seem near the big end feeding will work.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?
air density = 4*10-4 Kg/m3
Oops yes - it's deltaVolume = 400 cc that's needed to account for all the upthrust.If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?
air density = 4*10-4 Kg/m3
1.225 kg/m3 http://en.wikipedia.org/wiki/Density_of_air (http://en.wikipedia.org/wiki/Density_of_air)
I don't think you want the density of air, rather the change in density of air with temperature. If the it is a sealed volume then the total air mass will be the same at any temperature. But I guess you are calculating buoyancy which is the density of the outside-the-cavity air times the change in volume of the cavity.Oops yes - it's deltaVolume = 400 cc that's needed to account for all the upthrust.If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?
air density = 4*10-4 Kg/m3
1.225 kg/m3 http://en.wikipedia.org/wiki/Density_of_air (http://en.wikipedia.org/wiki/Density_of_air)
Still too big to reasonably expect.
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?
air density = 4*10-4 Kg/m3
If any calculated results from Meep are relevant then note that Meep calculates the largest thrust, O(1.1/c), when the antenna is dead center in the cavity. That is a point source. A dipole source is centered and parallel to the base plates for electric stimulation, and parallel to the axis of symmetry for magnetic stimulation.
Moving the antenna away from center reduces the detected force/flux ratio.
....
Be that as it may, the main reason that we went with the lower-Q TM modes was because they consistently produced higher thrust levels for a given input power than the TE modes. I will grant you though that getting the most thrust out of a particular resonant mode depended very painfully on the size, placement and rotational orientation of the loop antenna in the frustum cavity.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
I agree on the filament heating time causing the delay. It is best if you can allow the filament to heat up before applying the anode voltage. Also note that the center frequency and spectrum of a magnetron changes with the temperature of the tube. You may be observing that effect as well.Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
Well done!Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
Congratulations! You have shown a lot of ingenuity. One question I have however: What happens when you move the electronic scale a few inches so that it is not under the metal boom supporting the cavity and you apply power to the magnetron? Have you ruled out the possibility the RF energy is causing a false positive reading? Another possible source of a false positive is the stiffening of the power wires when the magnetron is on. This is due to magnetic forces between the conductors. Those are possible sorces of error in your experiment. I admire your ability to quickly build a workable test system.
Test 03 Success. I have thrust.
I modified the setup and now i weight the frustum. the precision is much better.
I will make a modifications to be able to adjust the cavity length to achieve the resonance, so i should have more thrust then.
Iulin Berca:
Congratulations on the success! I think this demonstration is fantastic. The fact that the peak thrust appears ~3 seconds after the power is turned on tells me it takes a little while for energy to 'build up' in the cavity. After the peak, the thrust slowly dies probably because the cavity walls are warping and you are losing resonance.
The adjustable end plate would certainly help to achieve a higher peak thrust, it just might take some trial and error. But I believe cavity will still heat up and warp and the thrust will taper off.
Maybe this thermal effect could be mitigated using some sort of heat sink?
I rather think the time difference between applying power and thrust is due to the time needed to heat up the filament (cathode) in the magnetron. After ~ 3.5 - 4 seconds you hear that buzz inside, exactly in that moment the thrust appears. After that the buzz drops a little bit and also the thrust. After work, i will turn the cavity upside down to see if i can have the opposite thrust.
Congratulations! You have shown a lot of ingenuity. One question I have however: What happens when you move the electronic scale a few inches so that it is not under the metal boom supporting the cavity and you apply power to the magnetron? Have you ruled out the possibility the RF energy is causing a false positive reading? Another possible source of a false positive is the stiffening of the power wires when the magnetron is on. This is due to magnetic forces between the conductors. Those are possible sorces of error in your experiment. I admire your ability to quickly build a workable test system.
In the wires for the filament the voltage is AC so they can not have to much effect in only one direction, just some 50hz low intensity vibrations.
The anode voltage is pulsed DC but the current is smaller ~ 5.3A.
I already tried the scale without weight and i do not have any disturbance in the reading when i power on the magnetron.
I can use an external supply for the filament , in this way i hope to adjust the power and maybe the frequency. But is very dangerous because i will connect the cathode with 4Kv to my power supply. The capacitance in the transformer can send some hi voltage to the supply.
In the wires for the filament the voltage is AC so they can not have to much effect in only one direction, just some 50hz low intensity vibrations.
The anode voltage is pulsed DC but the current is smaller ~ 0.2A.
I already tried the scale without weight and i do not have any disturbance in the reading when i power on the magnetron.
I can use an external supply for the filament , in this way i hope to adjust the power and maybe the frequency. But is very dangerous because i will connect the cathode with 4Kv to my power supply. The capacitance in the transformer can send some hi voltage to the supply.
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?1 litre weights about 1.2 grams, or 12 mN . Heated up by 10 degrees Kelvin it expands by about 1/30 , resulting in buoyancy of approximately 12/30 = 0.4 mN . Definitely enough to make an experiment inaccurate (4mN from 10 litres), albeit probably less than thermal and electromagnetic effects in cabling (which is basically impossible to estimate). edit: also, vibrations of something asymmetric in air should result in a force, which is also difficult to estimate.
air density = 4*10-4 Kg/m3
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?1 litre weights about 1.2 grams, or 12 mN . Heated up by 10 degrees Kelvin it expands by about 1/30 , resulting in buoyancy of approximately 12/30 = 0.4 mN . Definitely enough to make an experiment inaccurate (4mN from 10 litres), albeit probably less than thermal and electromagnetic effects in cabling (which is basically impossible to estimate).
air density = 4*10-4 Kg/m3
The only thing he can do with cabling as it is, is see if it replicates turned upside down, with some accuracy (~5% for example), without excessive fiddling. But it probably won't even if the effect is there because of all the classical forces.
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?1 litre weights about 1.2 grams, or 12 mN . Heated up by 10 degrees Kelvin it expands by about 1/30 , resulting in buoyancy of approximately 12/30 = 0.4 mN . Definitely enough to make an experiment inaccurate (4mN from 10 litres), albeit probably less than thermal and electromagnetic effects in cabling (which is basically impossible to estimate).
air density = 4*10-4 Kg/m3
The only thing he can do with cabling as it is, is see if it replicates turned upside down, with some accuracy (~5% for example), without excessive fiddling. But it probably won't even if the effect is there because of all the classical forces.
Would you agree drilling 6 x 1 mm diameter equally spaced holes around the circumference at both ends of the frustum wall, say 5 mm away from the end plates, and the same around the frustum middle would eliminate any buoyancy or hot air jet false positives?
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?1 litre weights about 1.2 grams, or 12 mN . Heated up by 10 degrees Kelvin it expands by about 1/30 , resulting in buoyancy of approximately 12/30 = 0.4 mN . Definitely enough to make an experiment inaccurate (4mN from 10 litres), albeit probably less than thermal and electromagnetic effects in cabling (which is basically impossible to estimate).
air density = 4*10-4 Kg/m3
The only thing he can do with cabling as it is, is see if it replicates turned upside down, with some accuracy (~5% for example), without excessive fiddling. But it probably won't even if the effect is there because of all the classical forces.
Would you agree drilling 6 x 1 mm diameter equally spaced holes around the circumference at both ends of the frustum wall, say 5 mm away from the end plates, and the same around the frustum middle would eliminate any buoyancy or hot air jet false positives?
I wouldn't assume that IMHO, on the basis that the Ph.D. thesis that Shawyer uses as his only reference on radiation pressure measurements (Dr. Cullen's thesis) makes it clear that Cullen had to use a mesh as follows to eliminate air effects that have plagued these experiments since Maxwell's times:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829247;image)
"drilling 6 x 1 mm diameter equally spaced holes around the circumference at both ends of the frustum wall, say 5 mm away from the end plates" would not be enough
It is puzzling to a researcher's mind that Shawyer uses Cullen as his only reference for radiation pressure from closed frustum cavities, when Cullen only used open waveguides with constant cross section in his pressure experiments, while Shawyer apparently ignores Cullen's prescription on the need for a wired mesh to eliminate gas effects.
.....Don't see how this relates to what EW, Shawyer and the Chinese did. None of those used the Cullen grid you are suggesting, so why bash Shawyer for not using it and not the others?...As I said, because Shawyer is the only one that uses Cullen as his only reference on pressure radiation for the unorthodox pressure radiation calculations that Shawyer uses. Neither Prof. Yang nor NASA Eagleworks use Cullen as a reference. Pointing out the huge inconsistency in Shawyer using as his only reference a work that explicitly does NOT use cavities but instead uses open waveguides is not bashing somebody, it is pointing out a technical inconsistency that should bother any engineer. Engineers care about accuracy. Engineers that make bridges care about accuracy and aerospace engineers care even more about accuracy (because of the weight constraints in aerospace engineering, the safety factor in aerospace engineering cannot be as high as in civil engineering, hence accuracy is paramount in aerospace engineering). It is something that referees in peer-reviewed journals point out whenever engineering papers are reviewed for publication approval in a peer-reviewed journal. Ditto for Shawyer using Cullen as a reference for what Cullen does not do (measure pressure on cavities) and ignoring Cullen's prescription on what Cullen recommends to do (to use a mesh to get rid of the gas effect).
BTW in the Egan paper, could you please show me where he factors in the constantly changing cutoff wavelength, guide wavelength & group velocity as the EM wave bounces from end to end in a frustum with constantly varying diameter? Really can't follow how he calcs the resonate frequency for his frustum.I can't help making it any more clear than what Greg Egan did. Greg Egan's paper is extremely clear to me, as he uses textbook material. Concerning the cut-off wavelength and associated cut-off frequencies, they are automatically built-in in the two eigenvalue problems that Egan addresses.
.....Don't see how this relates to what EW, Shawyer and the Chinese did. None of those used the Cullen grid you are suggesting, so why bash Shawyer for not using it and not the others?...As I said, because Shawyer is the only one that uses Cullen as his only reference on pressure radiation for the unorthodox pressure radiation calculations that Shawyer uses. Neither Prof. Yang nor NASA Eagleworks use Cullen as a reference. Pointing out the huge inconsistency in Shawyer using as his only reference a work that explicitly does NOT use cavities but instead uses open waveguides is not bashing somebody, it is pointing out a technical inconsistency that should bother any engineer. Engineers care about accuracy. Engineers that make bridges care about accuracy and aerospace engineers care even more about accuracy (because of the weight constraints in aerospace engineering, the safety factor in aerospace engineering cannot be as high as in civil engineering, hence accuracy is paramount in aerospace engineering). It is something that referees in peer-reviewed journals point out whenever engineering papers are reviewed for publication approval in a peer-reviewed journal. Ditto for Shawyer using Cullen as a reference for what Cullen does not do and ignoring Cullen's prescription on what Cullen recommends to do (to use a mesh).BTW in the Egan paper, could you please show me where he factors in the constantly changing cutoff wavelength, guide wavelength & group velocity as the EM wave bounces from end to end in a frustum with constantly varying diameter? Really can't follow how he calcs the resonate frequency for his frustum.I can't help making it any more clear than what Greg Egan did. Greg Egan's paper is extremely clear to me, as he uses textbook material. Concerning the cut-off wavelength and associated cut-off frequencies, they are automatically built-in in the two eigenvalue problems that Egan addresses.
When one has an exact solution like Egan, one does not have to artificially impose a cut-off condition as a side-condition. The reason why Shawyer has to impose the cut-off condition as a side-condition is because Shawyer's solution is obviously not an exact solution. Shawyer's solution does not satisfy the Boundary Conditions of the problem as it has been pointed out in the forum previously.
The fact that Greg Egan's solution automatically includes the cut-off condition (and not as a side-condition) in the eigenvalue problem is evident in the examples given by Egan: notice that the frequency and mode shape associated with the quantum number p=0, constant in the longitudinal direction of the truncated cone, is automatically cut-off by the eigensolution shown by Egan. The first natural frequency in the examples shown by Egan have p>0.
...It is clearly given by Egan in here http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html (for modes having the azimuthal quantum number m=0, but arbitrary n and p)
And his exact solution to calc the resonant frequency of a frustum with spherical end plates is?
...It is clearly given by Egan in here http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html (for modes having the azimuthal quantum number m=0, but arbitrary n and p)
And his exact solution to calc the resonant frequency of a frustum with spherical end plates is?
Egan even walks you through, step by step, examples of how to solve the eigenproblems for both the Legendre associated function and for the spherical Bessel function (there are textbooks that don't bother to walk the student through on how to solve the eigenproblem).
I really have a problem with this Egan's explanation, attached below, which assumes all the wavelengths inside the cavity are the same length, which we know is not the case. ...The solution shown in http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html has an infinite number of eigenwavelengths.
Looks like a photo of Shawyer's 1st knife edge balance beam test rig with the 1st EM Drive inside a sealed Faraday Cage.
http://www.shelleys.demon.co.uk/fdec02em.htm
Screws around the box seem to align up with the holes in the various mounting plates.
I really have a problem with this Egan's explanation, attached below, which assumes all the wavelengths inside the cavity are the same length, which we know is not the case. ...The solution shown in http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html has an infinite number of eigenwavelengths.
I don't understand why one would assume that in a practical situation only one eigenwavelength (or equivalently only one eigenfrequency) would take place. I don't think that Egan implies that. On the contrary, Cullen (the reference used by Shawyer to justify his unorthodox calculations) explicitly shows how hard it was for him in his experimental Ph.D. thesis to excite the waveguide at just one eigenfrequency, as many eigenmodes are close to each other. Cullen shows that it was practically impossible, the best he could do was to suppress the magnitude of other eigenfrequencies to a relatively low magnitude.
The reality is the contrary of what you apparently assume, Egan in http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html discusses a solution to an eigenvalue problem having an infinite number of eigenwavelengths and in reality it is very difficult to have the cavity resonate at a single pure eigenwavelength, as many eigenmodes are close to each other. This is particularly so when one uses a magnetron !
Looks like a photo of Shawyer's 1st knife edge balance beam test rig with the 1st EM Drive inside a sealed Faraday Cage.
http://www.shelleys.demon.co.uk/fdec02em.htm
Screws around the box seem to align up with the holes in the various mounting plates.
I like this, because besides of eliminating hot air buoyancy as an explanation, by showing the device producing thrust in any direction, the logical next step for any DYI fan is to run the device fully enclosed in a Faraday cage, showing it producing thrust in any direction as well. Such setup would still be affordable for most DYI fans capable of building an Emdrive.
And from there, what's needed are vacuum tests. But those are significantly more expensive for a regular DYI fan, and would be easier done by people in universities and labs with facilities like vacuum chambers.
If I did the calculation right, a volume change of ~125 litres would be needed to account for this apparent weight change, due to thermal ballooning of a sealed volume. That's far too high a change in volume that could be reasonably expected, so it can't be the whole story. Did I calculate this right?1 litre weights about 1.2 grams, or 12 mN . Heated up by 10 degrees Kelvin it expands by about 1/30 , resulting in buoyancy of approximately 12/30 = 0.4 mN . Definitely enough to make an experiment inaccurate (4mN from 10 litres), albeit probably less than thermal and electromagnetic effects in cabling (which is basically impossible to estimate).
air density = 4*10-4 Kg/m3
The only thing he can do with cabling as it is, is see if it replicates turned upside down, with some accuracy (~5% for example), without excessive fiddling. But it probably won't even if the effect is there because of all the classical forces.
Would you agree drilling 6 x 1 mm diameter equally spaced holes around the circumference at both ends of the frustum wall, say 5 mm away from the end plates, and the same around the frustum middle would eliminate any buoyancy or hot air jet false positives?
I wouldn't assume that IMHO, on the basis that the Ph.D. thesis that Shawyer uses as his only reference on radiation pressure measurements (Dr. Cullen's thesis) makes it clear that Cullen had to use a mesh as follows to eliminate air effects that have plagued these experiments since Maxwell's times:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829247;image)
"drilling 6 x 1 mm diameter equally spaced holes around the circumference at both ends of the frustum wall, say 5 mm away from the end plates" would not be enough
It is puzzling to a researcher's mind that Shawyer uses Cullen as his only reference for radiation pressure from closed frustum cavities, when Cullen only used open waveguides with constant cross section in his pressure experiments, while Shawyer apparently ignores Cullen's prescription on the need for a wired mesh to eliminate gas effects.
18 holes, 1mm diameter = 14.2mm^2 of total air hole area to allow the internally heat air to not cause buoyancy or hot air gas jet false positives. Much simpler than the Cullen grid. As engineer, the rule is KISS.
Don't see how this relates to what EW, Shawyer and the Chinese did. None of those used the Cullen grid you are suggesting, so why bash Shawyer for not using it and not the others?
BTW in the Egan paper, could you please show me where he factors in the constantly changing cutoff wavelength, guide wavelength & group velocity as the EM wave bounces from end to end in a frustum with constantly varying diameter? Really can't follow how he calcs the resonate frequency for his frustum.
Interesting version of the C band Flight Thruster and dimensions.Never seen this before ???
www.slideshare.net/Stellvia/emdrive-presentation-at-space-08-conference-barbican-london-presentation
....Sorry, that:
This grid might account for the unusual thermal signature of the large end base plate. Pardon my "warping" of the perspective to get it as close to a circle as time would permit.
This thermal pattern doesn't remind me of a concave surface pattern. It "could" be that the large base is copper-clad PC board with the "bulls eye" patern etched on the upper surface (connected to ground potential) and the bottom (outside) surface of the PC board completely copper. Perhaps this is the reason for the apparent thickness of the large base, a "suspended" pattern a few mm above the copper.
Just speculation...hope there is someone who can connect the dots. Original thermal image: https://d253pvgap36xx8.cloudfront.net/editor_uploads/1277/2015/05/06/NASA_emdrive2.jpg
Interesting version of the C band Flight Thruster and dimensions.Never seen this before ???
www.slideshare.net/Stellvia/emdrive-presentation-at-space-08-conference-barbican-london-presentation
Not a truncated cone.
What happened to the spherical waves?
Is there an explanation to its flat sides and the departure from the conical shape ?
[...For what it is worth, I obtained the same image (indistinguishable by eye) with my exact solution for the same mode shape TM212, using spherical ends. It looks like it doesn't make a perceptible difference for these geometrical dimensions and for this mode TM212 magnetic field whether one has flat ends or spherical ends.
Thanks Dr, in my world it was thermal. Interesting to note the interference pattern was divided into quadrants and the only image I could locate to explain it was the "diffuser". Soooo, guess no one did a thermal of the DUT?
...Bread crumbs? I feel like a bird ... :)
Shawyer likes to drop bread crumbs, to create a trail for those interested to follow.
Why would it matter? The miscalculation of radiation pressure upon inclined surfaces works the same for a truncated pyramid.Interesting version of the C band Flight Thruster and dimensions.Never seen this before ???
www.slideshare.net/Stellvia/emdrive-presentation-at-space-08-conference-barbican-london-presentation
Not a truncated cone.
What happened to the spherical waves?
Is there an explanation to its flat sides and the departure from the conical shape ?
The expectation for measured weight change for Iulian's device is about -0.5 gm-weight (becoming lighter), assuming a temperature rise of the air within the device of about 25oC, and assuming the device volume to be about 6 litres. The mechanism here is based simply on the change in weight of the air within the device. Because the device is not sealed, air can move in and out of it as its temperature changes. The larger the device volume, the larger the expected measured weight change.
I've now calculated the volume to be ~37 litres, and so we need roughly only 1/6th of the previously calculated temperature rise to get the observed weight change - just a few degrees will do it.
The expectation for measured weight change for Iulian's device is about -0.5 gm-weight (becoming lighter), assuming a temperature rise of the air within the device of about 25oC, and assuming the device volume to be about 6 litres. The mechanism here is based simply on the change in weight of the air within the device. Because the device is not sealed, air can move in and out of it as its temperature changes. The larger the device volume, the larger the expected measured weight change.
The characteristics of the heated air will depend significantly on its humidity too.
The expectation for measured weight change for Iulian's device is about -0.5 gm-weight (becoming lighter), assuming a temperature rise of the air within the device of about 25oC, and assuming the device volume to be about 6 litres. The mechanism here is based simply on the change in weight of the air within the device. Because the device is not sealed, air can move in and out of it as its temperature changes. The larger the device volume, the larger the expected measured weight change.
I've now calculated the volume to be ~37 litres, and so we need roughly only 1/6th of the previously calculated temperature rise to get the observed weight change - just a few degrees will do it.
The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
I miscalculated. I used diameter instead of radius. So divide that by 4 and we're back to aboutThe expectation for measured weight change for Iulian's device is about -0.5 gm-weight (becoming lighter), assuming a temperature rise of the air within the device of about 25oC, and assuming the device volume to be about 6 litres. The mechanism here is based simply on the change in weight of the air within the device. Because the device is not sealed, air can move in and out of it as its temperature changes. The larger the device volume, the larger the expected measured weight change.
I've now calculated the volume to be ~37 litres, and so we need roughly only 1/6th of the previously calculated temperature rise to get the observed weight change - just a few degrees will do it.
How on Earth did you come up with such a large volume? 37 litres is a cubic volume ~33.3 cm on a side. Even 6 litres is a cubic volume 18.17 cm on a side which is quite large.
Do we know the dimensions of the device?
The characteristics of the heated air will depend significantly on its humidity too.Yes, humid air will be heated practically instantaneously as microwave heating is not at all due to conduction or convection. Microwave heating is dielectric heating, the water molecule is an electric dipole, hence the water molecules rotate to align themselves with the alternating electric field of the microwaves. However, as pointed out by Warp-Tech, the tell tale sign is " why would it drop as soon as it's switched off" as the cooling has to proceed by convection (mostly) and conduction at the walls and that will be much slower than the experienced fast drop in measured force as soon as the electricity was turned off. There is no dielectric cooling.
Not so sure about that. Air is driven out by the pressure differential. As soon as the magnetron is switched off, the driver for that pressure difference vanishes and colder air rushes back in.Which has, for natural convection currents (that is what you propose) a significantly longer time constant. (Relatively slow air speeds compared to forced convection).
The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
Not so sure about that. Air is driven out by the pressure differential. As soon as the magnetron is switched off, the driver for that pressure difference vanishes and colder air rushes back in.
The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
I'd also like to point out that the thrust drops off the more it's run. If air were a significant contributor to the readings, you'd expect to see it go up (or rather, down) the more the device is run, no?
No, I think. Repeated runs occurring close in time to one another will tend to push up the average temperature. Therefore the change in temperature of the water vapour in the air, and of the air itself, will be that much less after several consecutive runs.The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
I'd also like to point out that the thrust drops off the more it's run. If air were a significant contributor to the readings, you'd expect to see it go up (or rather, down) the more the device is run, no?
The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
I'd also like to point out that the thrust drops off the more it's run. If air were a significant contributor to the readings, you'd expect to see it go up (or rather, down) the more the device is run, no?
No, I think. Repeated runs occurring close in time to one another will tend to push up the average temperature. Therefore the change in temperature of the water vapour in the air, and of the air itself, will be that much less after several consecutive runs.The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
I'd also like to point out that the thrust drops off the more it's run. If air were a significant contributor to the readings, you'd expect to see it go up (or rather, down) the more the device is run, no?
Since the air is not significantly contained, the pressure will equalise very rapidly, i.e. air will move about rapidly, so no significant thrust from air after power off would be expected. Instead, after power off, one would expect cooling, and a sucking back of air, resulting in a smaller force of the opposite magnitude. I expect that the air being expelled during the powered phase will be proportional to the rate of change of temperature, i.e. it would fall asymtotically as the chamber heats to steady state. This can be modelled. Assuming chamber is mostly sealed except for large vent holes in side. with holes top and bottom one might get constant convection through the device, like a pulse jet.I think the details are interesting, but the main takeaway from the "varying air mass" model is that it is of a calculated magnitude that is able to fully account for the measured "thrust".
Thinking we're seeing real thrust (not a heated air EM balloon). I watched the initial thrust degrading slowly during the test and I'm thinking this simply could be to the Microwave ionization of the air molecules inside of the Chamber causing the air to breakdown by avalanche ionization, in microwave propagation it can play a significant role. Changes in the Q, harmonics, wave patterns, due to these ionization effects could decrease the thrust like we are seeing. It takes a little time to build up an ionized plasma to the point it would start to de-tune the chamber and decay the thrust.The characteristics of the heated air will depend significantly on its humidity too.
Crank up the volume on the video, You can hear when the magnetron start to buzz and thrust appears immediately there after. When buzz stops, thrust stops. No delay.
Both of you could be correct. Although, I have to side with TheTraveller on this one. It would have to be a pretty drastic, and immediate change in temperature which would not have likely happened.
No, it's me :o
The air/water within the chamber will average to a higher temperature.
The ambient will stay ...ambient .
This isn't about buoyancy. It's about a simple change in the mass of air/water vapour within the cavity.
If this model is correct in accounting for the measured weight change, then we should see the same negative weight change when the cavity is flipped upside down.
When he makes a weight measurement, he is weighing the device plus whatever air/water vapour is inside it. Therefore when there is less air inside the device, the device will weigh less. It's as simple as that. Why should a higher temperature result in less air inside the device? - that's because the density of air depends on its temperature; it decreases with higher temperature. Since the device volume is constant and the density of air has dropped, there must be less air mass inside the device at higher temperature.If that was the case I would like you to consider that the air takes time to evacuate the chamber and internally heat the air. The scales would slowly increase instead the decrease like we see. This seem right?
mass = density * volume.
And this is no "tiny artifact" - it's an effect on order negative half a gram, which turns out to be exactly what was measured.
No, it doesn't seem right because I can't understand most of what you're saying.When he makes a weight measurement, he is weighing the device plus whatever air/water vapour is inside it. Therefore when there is less air inside the device, the device will weigh less. It's as simple as that. Why should a higher temperature result in less air inside the device? - that's because the density of air depends on its temperature; it decreases with higher temperature. Since the device volume is constant and the density of air has dropped, there must be less air mass inside the device at higher temperature.If that was the case I would like you to consider that the air takes time to evacuate the chamber and internally heat the air. The scales would slowly increase instead the decrease like we see. This seem right?
mass = density * volume.
And this is no "tiny artifact" - it's an effect on order negative half a gram, which turns out to be exactly what was measured.
@TheTraveller:
What are the units and semantics of your vertical scale?
So your thrust is in opposite direction from EagleWorks, right?
As per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
As per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
As per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
Reaction / EM Drive physical movement is in the opposite direction to Thrust direction. He has stated this many times.
The group velocity of the electromagnetic wave at the end plate of the larger
section is higher than the group velocity at the end plate of the smaller section. Thus
the radiation pressure at the larger end plate is higher that that at the smaller end plate.
The resulting force difference (F g1 -F g2 ) is multiplied by the Q of the resonant
assembly.
As per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
Reaction / EM Drive physical movement is in the opposite direction to Thrust direction. He has stated this many times.
http://www.emdrive.com/theorypaper9-4.pdfQuoteThe group velocity of the electromagnetic wave at the end plate of the larger
section is higher than the group velocity at the end plate of the smaller section. Thus
the radiation pressure at the larger end plate is higher that that at the smaller end plate.
The resulting force difference (F g1 -F g2 ) is multiplied by the Q of the resonant
assembly.
So, it would have to be mounted the larger plate forward if you want your ship to go forward.
As per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
Reaction / EM Drive physical movement is in the opposite direction to Thrust direction. He has stated this many times.
http://www.emdrive.com/theorypaper9-4.pdfQuoteThe group velocity of the electromagnetic wave at the end plate of the larger
section is higher than the group velocity at the end plate of the smaller section. Thus
the radiation pressure at the larger end plate is higher that that at the smaller end plate.
The resulting force difference (F g1 -F g2 ) is multiplied by the Q of the resonant
assembly.
So, it would have to be mounted the larger plate forward if you want your ship to go forward. According to his "theory" anyway. No idea where his experiments are going, my guess is which ever ways vibration and shifts in the centre of mass take them.
http://exploration.grc.nasa.gov/education/rocket/rktth1.htmlAs per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
Reaction / EM Drive physical movement is in the opposite direction to Thrust direction. He has stated this many times.
http://www.emdrive.com/theorypaper9-4.pdfQuoteThe group velocity of the electromagnetic wave at the end plate of the larger
section is higher than the group velocity at the end plate of the smaller section. Thus
the radiation pressure at the larger end plate is higher that that at the smaller end plate.
The resulting force difference (F g1 -F g2 ) is multiplied by the Q of the resonant
assembly.
So, it would have to be mounted the larger plate forward if you want your ship to go forward.
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
When he makes a weight measurement, he is weighing the device plus whatever air/water vapour is inside it. Therefore when there is less air inside the device, the device will weigh less. It's as simple as that. Why should a higher temperature result in less air inside the device? - that's because the density of air depends on its temperature; it decreases with higher temperature. Since the device volume is constant and the density of air has dropped, there must be less air mass inside the device at higher temperature.
mass = density * volume.
And this is no "tiny artifact" - it's an effect on order negative half a gram, which turns out to be exactly what was measured.
http://exploration.grc.nasa.gov/education/rocket/rktth1.htmlAs per Shawyer's theory papers, it should be moving wide end forward.So your thrust is in opposite direction from EagleWorks, right?
Movement is as per Shawyer. From the big end toward the small end.
Watch the video to see which way it moves.
http://emdrive.com/dynamictests.html
Reaction / EM Drive physical movement is in the opposite direction to Thrust direction. He has stated this many times.
http://www.emdrive.com/theorypaper9-4.pdfQuoteThe group velocity of the electromagnetic wave at the end plate of the larger
section is higher than the group velocity at the end plate of the smaller section. Thus
the radiation pressure at the larger end plate is higher that that at the smaller end plate.
The resulting force difference (F g1 -F g2 ) is multiplied by the Q of the resonant
assembly.
So, it would have to be mounted the larger plate forward if you want your ship to go forward.
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
...
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
Might be hard to roll into a smooth frustum.
I plan to drill 6 x 1mm diameter holes 5mm in from each end of the frustum and the same around the central diameter to allow heated air to escape without causing any major issues.
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
...
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
Might be hard to roll into a smooth frustum.
I plan to drill 6 x 1mm diameter equally spaced holes 5mm in from each end of the frustum and the same around the central diameter to allow heated air to escape without causing any major issues.
No, I don't know that....
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
As you well know it was measured and reported here:
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
Might be hard to roll into a smooth frustum.
I plan to drill 6 x 1mm diameter equally spaced holes 5mm in from each end of the frustum and the same around the central diameter to allow heated air to escape without causing any major issues.
Hm. I can see folks being more comfortable with holes around the central diameter. Holes at either end could result in debates over whether this was causing thrust towards one end or the other, biasing the results...
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
It should not matter. Millions of microwave ovens with glass transparent to microwaves are covered with this perforated metal to prevent the microwaves from escaping the microwave open and hurting humans.
At least the small and big flat ends could be made of perforated metal.
The opening in the mesh is equivalent to a very small wavelength.
(http://makeitorfixit.com/wp-content/uploads/2014/01/MicrowaveDoor.jpg.jpg)
...
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
Might be hard to roll into a smooth frustum.
I plan to drill 6 x 1mm diameter equally spaced holes 5mm in from each end of the frustum and the same around the central diameter to allow heated air to escape without causing any major issues.
Hm. I can see folks being more comfortable with holes around the central diameter. Holes at either end could result in debates over whether this was causing thrust towards one end or the other, biasing the results...
Holes would be in the side walls, not in the end plates. Hard to see how 6 x 1mm diameter holes even spaced around the ends of the frustum could generate significant thrust.
Easy to block and unblock during different test runs.
No, I don't know that....
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
As you well know it was measured and reported here:
I see a chart that Shawyer put together. Nobody here could explain why the Demo Engine has it in both directions.
I never saw a paper detailing how such a thrust was measured simultaneously with measuring the acceleration in the opposite direction.
...
Shawyer is in business to sell licenses, not to give it all away so any DIY guy can replicate and go into business against SPR and it's clients.
There are holes in what he has put in the public domain. I doubt he has any intention of filling them in. For guys like me, working to replicate the EM Drive, we need to learn to follow the bread crumb trail he has left. For me, that trail is strong and delivering good intel.
I'm highly confident of replicating his Flight Thruster and getting close to his results.
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
So should everyone be using perforated copper sheeting?? Admittedly, I can't even begin to imagine how this would affect the performance of the drive. Do the various theories need a solid wall or as long as the perforations are sufficiently fine it should not matter?? :P
https://concordsheetmetal.com/store/perforated-copper/ (https://concordsheetmetal.com/store/perforated-copper/)
Good thoughts as the mesh would be a cost-effective solution for trials, however, its likely going to be a lower Q which theoretically inhibit power/effeciency. My old company used this exact material in an impedance matching network, while a competitor used solid aluminum. At the end of the day, the 50 ohm freq matching was extended abt 25% by using the more expensive solid cone. I'd suggest initial proof of performance testing on the mesh, moving up to silver-plated flash over copper.
Another topic I have not see discussed is intermodulation products caused by dissimilar metals, perhaps nickel( Magnetic)-plating of connectors and such. I'm not sure if IM products would adversly affect the trials, as the magnetron is inherently spraying out bits all over the spectrum.
No, I don't know that....
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
As you well know it was measured and reported here:
I see a chart that Shawyer put together. Nobody here could explain why the Demo Engine has it in both directions.
I never saw a paper detailing how such a thrust was measured simultaneously with measuring the acceleration in the opposite direction.
Shawyer is in business to sell licenses, not to give it all away so any DIY guy can replicate and go into business against SPR and it's clients.
There are holes in what he has put in the public domain. I doubt he has any intention of filling them in. For guys like me, working to replicate the EM Drive, we need to learn to follow the bread crumb trail he has left. For me, that trail is strong and delivering good intel.
I'm highly confident of replicating his Flight Thruster and getting close to his results.
Shawyer has patents on the EM Drive. One of the fundamental agreements and understanding under which patents are conferred by a state (or the European Union) to an inventor is that the inventor must disclose all the "information material to patentability." See: Duty to disclose information material to patentability.
In intellectual property one always has to make a choice: trade secret (like the Coca Cola formula) or patent.
Under trade secret you run the risk that the secret may become public (by independent discovery), but as long as it is a trade secret it has no expiration.
A patent gives you a state-conferred monopoly, but it has an expiration date. The state gets to make the patent information public in exchange for conferring the patent's monopoly to the inventor.
I'm sure that Shawyer would disagree with your statement if you are referring to information material to patentability protected by Shawyer's patents.
On the other hand, if you are not referring to information material to patentability, then the information you are referring to "so any DIY guy can replicate and go into business" is not protected by Shawyer's patents.
[...These are all the patent documents I know of, that have been posted in this thread. All of them are UK patent applications.
Has anyone tried to pull a copy of the patent from the patent office?
I saw the chart and thought the same thing, it is a conundrum leaving me to just scratch my head perplexed.No, I don't know that....
Spacecraft move in the opposite direction to the thrust of the engine. EM Drive is no different.
Propellant comes out of a rocket engine. According to Shawyer nothing comes out of an EM Drive.
If nothing is coming out of the EM Drive, how can it have a thrust force in the opposite direction to its acceleration?
Has someone measured that thust force you are referring to ? If this thrust force of the EM Drive has been measured, how was the thrust force measured simultaneously with a measurement of the acceleration in the opposite direction ?
???
As you well know it was measured and reported here:
I see a chart that Shawyer put together. Nobody here could explain why the Demo Engine has it in both directions.
I never saw a paper detailing how such a thrust was measured simultaneously with measuring the acceleration in the opposite direction.
Back of the envelope calculation for the 'hot air balloon' explanation, considering the pessimistic possibility that we just have a really heavy, electric powered Chinese sky lantern:
...
Thanks for running the numbers :)
What is the basis for the air flow rate (volume) = 0.0097 m^3 / s ? is it an assumption or is it an outcome of equations? if an outcome of equations, what where the equations or theory used in the calculator?
[...These are all the patent documents I know of, that have been posted in this thread. All of them are UK patent applications.
Has anyone tried to pull a copy of the patent from the patent office?
I don't know whether any patents were actually conferred for the EM Drive.
Under justia, this is all that shows up (not an EM Drive patent):
http://patents.justia.com/inventor/roger-j-shawyer (http://patents.justia.com/inventor/roger-j-shawyer)
Same under Google patents
and I couldn't find his EM Drive patents under USPTO search under inventor either
Did you find any?
I edited my post to read: patent (applications ?). Thanks for questioning, as I didn't recall that all (apparently ?) that has been posted here are just applications in the UK.
Back of the envelope calculation for the 'hot air balloon' explanation, considering the pessimistic possibility that we just have a really heavy, electric powered Chinese sky lantern:
...
Thanks for running the numbers :)
What is the basis for the air flow rate (volume) = 0.0097 m^3 / s ? is it an assumption or is it an outcome of equations? if an outcome of equations, what where the equations or theory used in the calculator?
I just plugged the numbers into a convection calculator:
http://www.engineeringtoolbox.com/convective-air-flow-d_1006.html
Clearly, this is an approximation, but I think it is sufficient for the purpose of showing that one cannot completely rule out a thermal (hot air balloon) effect for this particular result, as a rapid replacement of the air in the chamber is theoretically possible (assuming it is well ventilated), so it is possible to see a rapid loss of up-thrust after power-off.
Finding similar thrust in other orientations would rule this out, although the possibility of temporary thrust due to thermal expansion causing directed air flow, and sustained air flow due to jet effects would still exist; directed air flows of just a few percent of the frustum's volume per second are sufficient to cause this effect, which is easily possible when you are pumping a kilowatt of power into a small space.
From the pdf's
Shawyer uses/used an internal "dielectric"
Please remember this is a long thread and this site's forum has a high signal to noise factor.It would also be helpful if people wouldn't reproduce a whole quotation, but just the sentence that is being responded to. Anyone interested in reading the whole original post can click on the quote to see the original post, so the whole post doesn't need to be posted again (many times the original post being quoted is just above the response). The use of ellipsis (...) reduces bandwidth and makes a page cleaner. :)
...
OK all good points. But it is not at all clear that one wants a high Q.
The highest thrust was achieved by Prof. Yang with an effective Q of only ~1500 (take into account that the reported Q's appear much larger because of the unorthodox way the Chinese report Q, if one uses the same method as in the West, Yang's Q was relatively low).
Todd's theory shows that one doesn't want a huge Q.
So using a mesh would be of research interest, to see what difference it makes., whether it makes no difference, or is worse or better
...What I stated was
OK I'm scratching my head. Can't find where the Chinese state higher thrust needs lower Q. Maybe you can find it for me?
...
...The highest thrust was achieved by Prof. Yang with an effective Q of only ~1500 (take into account that the reported Q's appear much larger because of the unorthodox way the Chinese report Q, if one uses the same method as in the West, Yang's Q was relatively low)...
...What I stated was that Prof. Yang has achieved the record highest thrust recorded for the EM Drive and that the Q's she conducted the experiments at (when calculated the same way as they are calculated in the West) are low Q~1500 when compared to Shawyer's Q (hat tip to Star-Drive and zen-in for first uncovering this)
OK I'm scratching my head. Can't find where the Chinese state higher thrust needs lower Q. Maybe you can find it for me?
Can find it stated for the 4 modes examined, higher Q = higher thrust as attached.
...
I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.
BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.
I see now this was your assumption and not from the paper.
Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.
...
I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.
BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.
I see now this was your assumption and not from the paper.
Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.
Well, read them again, and this time please figure out by yourself how Yang calculates the Q in her tables :)
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369553#msg1369553
Particularly read, in Chinese, Prof. Yang's most recent paper containing the embedded thermocouple temperature measurements, that spell this out very clearly.
...Not as quick note on the Internet. With all due respect to Dr. Rodal- his characterization of the Internet (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1375139#msg1375139) is a bit inaccurate....Yes I corrected myself in a subsequent message (*):
I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.
BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.
I see now this was your assumption and not from the paper.
Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.
As to how to get a frustum that has constantly varying internal wavelengths to resonate at each end plate, from a different applied Rf wavelength, well I'm working on that. Might be my secret squirrel secret sauce.
Quick note on Iulian's test; this was his third attempt. Unless I'm missing something, wouldn't have any thermal effects have shown up on those earlier tests at least in some form or was his measurements not accurate enough to measure that small of an effect?
Not as quick note on the Internet. With all due respect to Dr. Rodal- his characterization of the Internet (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1375139#msg1375139) is a bit inaccurate. Yes, there are plenty of distractions to be had, but to those with developed critical thinking skills, the Internet can be a fantastic tool.
In fact, the Internet was invented *for discussions just like this one*. Scientists getting together to share information and collaborate in new ways across distance and experience. This discussion has been an amazing example of social science application of this tool. Besides Dr. Rodal and the EW team's contributions, there's been several DIYers, mathematicians, skeptics, and scientists of all strips all tossing in ideas.
But then, out of that, there's been WarpTech's now known 'Todd Conjecture'. SeeShell's waveform expertise, seeing microwaves in hot tubs. Iulian's new much-debated video. Contributions from around the world. All the people working together here that have been pushing the literal boundaries of human understanding.
Having watched the Internet grow from it's ARPA/DARPA days in the 70's and 80's through to the ubiquitous tool that it is today, seeing exploration like this happening is an amazing experience; no matter *what* comes of this EM drive experimentation.
Yes, it's a bit like the Tower of Babel come to life, millions of voices all reaching out at once. But the Internet is a tool. And like any tool used in the hands of those with critical thinking skills, it becomes a powerful tool indeed.
Keep up the good work! This is an amazing time in human history to be doing science.
The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated?
Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.
My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?
Probably wouldn't need to use screen, just ultra thin copper bases. They should deform in one direction or the other. The direction of the deformation would say a lot about the force. If an untra thin copper sheet deformed differently than a copper screen, that might say that the effect is happening within the skin depth of the copper? One might even be able to string thin wires in one direction only, a screen with all of the y-direction wires removed. Then using the lower resonance modes only, the screen deformation might show a pattern of the forces. Might not, too.The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated?
Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.
My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?
That's a great way to conduct research on optimization and to understand something complicated. It reminds me of how the first human powered plane design came about. The Gossamer Condor beat the MIT design (that was based on analysis) by evolutionary refinement of the design based on a large number of tests.
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Is this the psychic blog? Great idea! I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests.
Todd D.
I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.Is this the psychic blog? Great idea! I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests.
Todd D.
I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.
I get the impression the current in the 1/4 wave stub moves with the electric field of the incoming radiation for constructive interference and the 3/4 frustum I am guessing would be working against the radiation and be attenuated. Is this similar to a directional antenna array? I am not quite seeing the picture but I think I might understand the concept.
I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically.
BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.
I see now this was your assumption and not from the paper.
Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.
As to how to get a frustum that has constantly varying internal wavelengths to resonate at each end plate, from a different applied Rf wavelength, well I'm working on that. Might be my secret squirrel secret sauce.
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
..Excellent statement: "The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically"
I was the one that said that optimizing for a higher Q is counterproductive for generating thrust, not Yang. Here is my logic;
The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically. The Q is the energy stored/loss per cycle. So increasing Q by decreasing the loss per cycle, effectively it MUST reduce the amount of attenuation such that there is less thrust transferred to the frustum. Alternatively, if you increase Q by storing more energy, without altering the amount of power attenuated, then there is more energy in reserve to draw from. If the system used PWM, it could sustain a longer duty cycle.
So there are advantages to higher Q that can produce a higher thrust, but optimizing Q at the expense of reducing the attenuation, will lower the thrust, IMO.
...
...
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.
Todd D.
Probably wouldn't need to use screen, just ultra thin copper bases. They should deform in one direction or the other. The direction of the deformation would say a lot about the force. ...
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.
Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.
If we can find the dimension<M
The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.
If either end is flat, the bounce will introduce very significant phase distortion into the returning curved wave. For me it is hard to see that Shawyer ever used flat end plates INSIDE the cavity. As we never saw inside the cavity, what is to say he didn't use curved end plates inside and flat end covers outside? What he drew may not be what he built.
QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Earth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.
Mike
QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.
Mike
Earth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.
Mike
Well, firstly, Shawyer has greater radiation pressure upon the wide end, but his drive is pushing narrow end forwards.Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
Well, firstly, Shawyer has greater radiation pressure upon the wide end, but his drive is pushing narrow end forwards.Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
Secondarily, yes, there is an interaction between the EM field and the walls, which results in a force on the side walls, equal to change in momentum of the EM field travelling down it, per time.
The number of photons (N) inside a cavity is not conserved. A photon may collide with an electron on a wall, exciting it to a higher energy state, removing a photon. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the cavity. Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary.
The absorption (emission) of one photon might be accompanied by the emission (absorption) of more than one photon, as long as the frequency of the photons involved are such that the energy of the system remains constant.
N over volume, and the entropy density are proportional to the cube of the temperature of the photon gas, while the pressure and the energy density are proportional to the fourth power of its temperature.
For black body radiation it can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero.
How does the Entropy/Information Bound Work? http://arxiv.org/pdf/quant-ph/0404042
Ah, found it. Dr. Rodal please note well the highlighted section in the 2nd attachment.Thank you for the information.
Here is how Shawyer measured his 2 force measurements on his Demonstrator EM Drive as per the 4th results line of the 1st attachment.
He used the rotary test rig and measured the acceleration and deceleration forces generated by the EM Drive. Did this in both directions. IE CW acceleration, then CW deceleration, then CCW acceleration, then CCW deceleration.
Clever boy our Roger.
Thank you for the information.
My question was how were the two forces (what Shawyer calls "reaction" and "thrust") measured simultaneously (I had labored to use Italics first and then bold and blue to highlight "simultaneously").
From the description provided it looks like there has been no experiment measuring simultaneously the two forces (what Shawyer calls "reaction" and "thrust") that (quoting you) "Clever boy our Roger" claims to have measured.
All that is being measured is displacement vs. time (or its second-order derivative with respect to time, whatever its sign) of the device
The problem with making measurements in acceleration and deceleration and then ascribing the results to the two forces are evident.
...there is an interaction between the EM field and the walls, which results in a force on the side walls, equal to change in momentum of the EM field travelling down it, per time.
I was wondering if we would be able to get a faster turnaround with prototyping and maybe even cut costs if we could use 3D printing and e.g. conductive graphene filament like this one:
We could share computer designs and use local 3D printing services. Would that work?
Earth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.
Mike
Frustum would need to constantly accelerate to be able to see resonant frequency changes.
Hello. I've been reading this thread and Iulian's blog with great interest. I'm just wondering if all of the calculations on possible thrust have only been done on truncated cones or cylinders... after Mr. Iulian retries his experiment inverting the frustrum to see if it's a metal hot air balloon, I'm curious what would happen if...one used a conical bore similar to the bell of a brass musical instrument. As an experiment, has anyone tried these experiments using a shape similar to the bell end of a tuba, sousaphone, french horn, etc? It would probably be pretty easy to try this experiment using a shape similar to this... maybe with a different material? If this has been addressed (or if a dumb question) I'll remove my post...thanks!Welcome to the thread :). Other shapes have been tried, for example, the Cannae drive:
(http://1.bp.blogspot.com/-ZielDMfkg38/Uytay8ovEtI/AAAAAAAAVjI/gJe4UhUkKm8/s1600/Bell+cut.jpg)
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
To clarify your point, electromagnetic fields can be measured directly, without measuring tiny forces. A page back I posted a rough calculation: to get >50uN from 50W pumped into a cavity with a Q of ~7000 , the microwaves at the surface of the cavity must deviate from the accepted solution by at least ~2.5% . (With Cannae drive giving similar results, the cavity shape is clearly not very important).Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
1-2-3) It really doesn't make sense to talk about "group velocity", "cutoff wavelength" for different "ends" in this case. A cavity is not a waveguide. Introducing end plates (whether curved or flat) changes the boundary conditions and thus the mode structure of the EM fields. There is just one cutoff wavelength for the entire cavity, much like an organ pipe has one "fundamental" tone.
Please understand that Egan's calculation of the fields is an exact solution of Maxwell's equations. Shawyer's talk about waveguides is at best a sloppy approximation.
4-5-6) There are forces on all surfaces of the cavity. Again referring to Egan's website, in the standard formulation of Maxwell's equations, for any closed cavity supporting time-harmonic fields, the integral of forces on the walls vanishes. To suggest Maxwell's equations say otherwise is just bad physics.
Generically, a question I asked many many pages ago, and that everyone has danced around: if the EM drive works, we must have a non-classical coupling of electromagnetic fields to something else. Why has this coupling never been observed before? What is special about a copper cone?
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
1-2-3) It really doesn't make sense to talk about "group velocity", "cutoff wavelength" for different "ends" in this case. A cavity is not a waveguide. Introducing end plates (whether curved or flat) changes the boundary conditions and thus the mode structure of the EM fields. There is just one cutoff wavelength for the entire cavity, much like an organ pipe has one "fundamental" tone.
Please understand that Egan's calculation of the fields is an exact solution of Maxwell's equations. Shawyer's talk about waveguides is at best a sloppy approximation.
4-5-6) There are forces on all surfaces of the cavity. Again referring to Egan's website, in the standard formulation of Maxwell's equations, for any closed cavity supporting time-harmonic fields, the integral of forces on the walls vanishes. To suggest Maxwell's equations say otherwise is just bad physics.
Generically, a question I asked many many pages ago, and that everyone has danced around: if the EM drive works, we must have a non-classical coupling of electromagnetic fields to something else. Why has this coupling never been observed before? What is special about a copper cone?
The number of photons (N) inside a cavity is not conserved. A photon may collide with an electron on a wall, exciting it to a higher energy state, removing a photon. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the cavity. Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary.
The absorption (emission) of one photon might be accompanied by the emission (absorption) of more than one photon, as long as the frequency of the photons involved are such that the energy of the system remains constant.
N over volume, and the entropy density are proportional to the cube of the temperature of the photon gas, while the pressure and the energy density are proportional to the fourth power of its temperature.
For black body radiation it can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero.
How does the Entropy/Information Bound Work? http://arxiv.org/pdf/quant-ph/0404042
One point to keep in mind is that the change from 2GHz to ambient thermal radiation is an up-conversion, that is, it represents a negative entropy change component that must be more than made up somewhere else.
As an example we consider the Casimir effect with different temperatures between the plates (T) resp. outside of them (T′). For T′ < T the pressure of heat radiation can eventually compensate the Casimir force and the total pressure can vanish...If both T and T′ are fixed (isothermal case), this equilibrium has turned out unstable.Thermodynamics of the Casimir effect http://arxiv.org/pdf/quant-ph/9902074v1
Nope. Maxwell's equations are field equations and have nothing about waves hitting anything at an angle. They also work for a solenoid plugged into your household AC.Well, firstly, Shawyer has greater radiation pressure upon the wide end, but his drive is pushing narrow end forwards.Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Where is Shawyer wrong?
1) Is the cutoff wavelength different at the small and big ends or not?
2) Is the guide wavelength different at the small and big ends or not?
3) Is the group velocity different at the small and big ends or not?
4) Is the bounce force different at the small and big ends or not?
5) Is the bounce force at the big end greater than at the small end or not?
6) Is there a bounce force on the side walls or not?
Just trying to understand where you believe Shawyer is wrong?
Secondarily, yes, there is an interaction between the EM field and the walls, which results in a force on the side walls, equal to change in momentum of the EM field travelling down it, per time.
Maxwell has a cosine factor to adjust for waves that hit the bounce surface at an angle. Max force at the end plates and min force at the walls as attached.
I think you're confused with regards to how forces and reaction works...
CofM requires if the EM waves pushes more on the on the big end than the small end, the EM Drive frustum pushes back in the opposite direction of the imbalance. Momentum transfer is not one sided. If the EM Drive moved toward the big end, then CofE would be violated as only a one sided push.
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
I thought my brain was being warped at the Super Conductor Super Collider, but this is a lot of fun. Love the pool of thoughts and ideas here it keeps me young and thinking.
We could pull it behind my 65 Pontiac Catalina. :) NASA has already proven that a 421 powered Pontiac will make things fly.
http://www.dfrc.nasa.gov/Gallery/Movie/M2-F1/HTML/EM-0020-02.html
I thought my brain was being warped at the Super Conductor Super Collider, but this is a lot of fun. Love the pool of thoughts and ideas here it keeps me young and thinking.
We could pull it behind my 65 Pontiac Catalina. :) NASA has already proven that a 421 powered Pontiac will make things fly.
http://www.dfrc.nasa.gov/Gallery/Movie/M2-F1/HTML/EM-0020-02.html
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too. I have a 2500 sq ft shop with all kind of toys for metal and electronics left over from my business. I'm not the kind to just throw it together and there is a lot of research yet to be done. And there will be shielding!
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.
Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
20 microns is 0.0008 of an inch and quite impressive (I built and designed XYZand T semiconductor machines with an positional accuracy of .25 um across 300mm) Is the price dropped low enough vs the real advantages of just using digital micrometers and good machining practices? To me nothing is really set in stone in the cavity designs and it seems like every day some new revelation pops up. Has 3D printing (with metals or conductors) dropped that low? I at least want to built it somewhat modular and that can allow design changes.
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
I think weight is a consideration, so I've crossed off steel. Also copper can not be anodized with silver, though there may be other techniques that can plate it. Silver will raise the Q factor as I understand it. A copper/aluminum alloy can be anodized with silver, as can aluminum itself.
For these reasons I've settled on aluminum until I find reason to pick something else.
Also 3D printing allows for additional weight savings, some of the parts can have internal cavities. 3D printing can be done at a resolution of 20 microns.
A thought experiment:
Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. Briefly they claim an additional finite dimension between our brane (weak/Tev) and a gravity brane (strong) where gravity actually exists. The distance between these branes is the reason that gravity is such a comparatively weak force. The length of this 4th spacial dimension has an upper limit of somewhat less than 1 millimeter (otherwise we would have seen its effects long ago). The force of gravity on the gravity brane is expected to be 16 orders of magnitude greater than it is on our brane....
For whatever it's worth, a short note that Dr. White and Paul March both have invoked a (4+1) brane of spacetime in their explanation and papers.
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
I think weight is a consideration, so I've crossed off steel. Also copper can not be anodized with silver, though there may be other techniques that can plate it. Silver will raise the Q factor as I understand it. A copper/aluminum alloy can be anodized with silver, as can aluminum itself.
For these reasons I've settled on aluminum until I find reason to pick something else.
Also 3D printing allows for additional weight savings, some of the parts can have internal cavities. 3D printing can be done at a resolution of 20 microns.
20 microns is 0.0008 of an inch and quite impressive (I built and designed XYZand T semiconductor machines with an positional accuracy of .25 um across 300mm) Is the price dropped low enough vs the real advantages of just using digital micrometers and good machining practices? To me nothing is really set in stone in the cavity designs and it seems like every day some new revelation pops up. Has 3D printing (with metals or conductors) dropped that low? I at least want to built it somewhat modular and that can allow design changes.
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
I think weight is a consideration, so I've crossed off steel. Also copper can not be anodized with silver, though there may be other techniques that can plate it. Silver will raise the Q factor as I understand it. A copper/aluminum alloy can be anodized with silver, as can aluminum itself.
For these reasons I've settled on aluminum until I find reason to pick something else.
Also 3D printing allows for additional weight savings, some of the parts can have internal cavities. 3D printing can be done at a resolution of 20 microns.
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.
Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Guess you have not read the Chinese data:
http://www.emdrive.com/NWPU2010translation.pdf
http://www.emdrive.com/NWPU2010testresults.pdf
http://www.emdrive.com/yang-juan-paper-2012.pdf
The thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
as a quick way to dismiss their results.
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
I think weight is a consideration, so I've crossed off steel. Also copper can not be anodized with silver, though there may be other techniques that can plate it. Silver will raise the Q factor as I understand it. A copper/aluminum alloy can be anodized with silver, as can aluminum itself.
For these reasons I've settled on aluminum until I find reason to pick something else.
Also 3D printing allows for additional weight savings, some of the parts can have internal cavities. 3D printing can be done at a resolution of 20 microns.
Both brass and copper take to electroplating with silver nicely and would provide a higher Q than bare copper.
Keep in mind that any metal can be plated with the right combination. A chrome car bumper was steel, plated with copper, plated with nickel, plated with chrome, the nickel won't plate very well directly to steel...
A thought experiment:
Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221.
I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.
A thought experiment:
Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221.
I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.
I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.
If you use solid copper sheeting for the body of the EM device and that seems to be because of it's thermal and electrical conductivity, couldn't you use a different extruded metal? Extruded Brass comes to mind, 90% copper and 10% tin. Or steel? Unless someone can provide me with as reason why I should just use copper sheeting. Yes, I'm thinking about building one too.
I think weight is a consideration, so I've crossed off steel. Also copper can not be anodized with silver, though there may be other techniques that can plate it. Silver will raise the Q factor as I understand it. A copper/aluminum alloy can be anodized with silver, as can aluminum itself.
For these reasons I've settled on aluminum until I find reason to pick something else.
Also 3D printing allows for additional weight savings, some of the parts can have internal cavities. 3D printing can be done at a resolution of 20 microns.
Both brass and copper take to electroplating with silver nicely and would provide a higher Q than bare copper.
Keep in mind that any metal can be plated with the right combination. A chrome car bumper was steel, plated with copper, plated with nickel, plated with chrome, the nickel won't plate very well directly to steel...
Yes, electroplating is the way to go (there is so much to learn here) - aluminum still seems the best choice for its lower weight. I see that copper can also be 3D printed: http://3dprint.com/59881/nasa-3d-prints-copper-rocket/.
How about extrapolating/interpolating downward by calculating dimensions from resonant frequencies of these test articles? Use that interpolation to select a smaller sized set of cavity dimensions and scale up the frequencies to get that thrust signal out of the "iffy" zone?The point I was making was that we don't know whether or not higher frequencies produce higher thrust. That's unless you happen to know.
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.
Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Guess you have not read the Chinese data:
http://www.emdrive.com/NWPU2010translation.pdf
http://www.emdrive.com/NWPU2010testresults.pdf
http://www.emdrive.com/yang-juan-paper-2012.pdf
The thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
as a quick way to dismiss their results.
A.single paper is not a magic wand which causes all previous results to disappear. It cannot chan ge the tens of thousands of previous measure ments that have taken place in the last 50years. How do you refute cavities in pillbox shape that are used in GPS satellite atomic clocks? These have been characterized down to sub nanowatt levels, and no mystery power draw is observed and no thrust is observed in the GPS satellites (the location of which must be known very well.)
How about extrapolating/interpolating downward by calculating dimensions from resonant frequencies of these test articles? Use that interpolation to select a smaller sized set of cavity dimensions and scale up the frequencies to get that thrust signal out of the "iffy" zone?The point I was making was that we don't know whether or not higher frequencies produce higher thrust. That's unless you happen to know.
How about extrapolating/interpolating downward by calculating dimensions from resonant frequencies of these test articles? Use that interpolation to select a smaller sized set of cavity dimensions and scale up the frequencies to get that thrust signal out of the "iffy" zone?
Knocking on Heaven's Door and another about the Higgs. Think it's 3.A thought experiment:
Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221.
I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.
I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.
It is somewhat light but meant for a specific audience, but she likes the string theory (I always liked it) and if you can write and make sense from our perspective another dimension without higher order math, my hat is off.
I keep on associating (several papers and books) again and again to magneto-chiral matter and how it interacts to the Casimir force and momentum, there seems a wonderful link there. "I'M GIVIN' HER ALL SHE'S GOT, CAPTAIN!" Need more brains!
It should be pointed out that this Shawyer thrust equation
1) F = 2 Df Po Q / c
has been rejected by the physics community. Their version is
2) F = 0.
Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.
But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes
3) F = (2 E/c) w
and thus thrust scales linearly with frequency, and linearly with the stored energy.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.
Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.
Thus the Mettler should detect thrust for Q > 100.
This is usually far exceeded by optical cavities, which can have Qs up in the millions.
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
...
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
A thought experiment:
Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. Briefly they claim an additional finite dimension between our brane (weak/Tev) and a gravity brane (strong) where gravity actually exists. The distance between these branes is the reason that gravity is such a comparatively weak force. The length of this 4th spacial dimension has an upper limit of somewhat less than 1 millimeter (otherwise we would have seen its effects long ago). The force of gravity on the gravity brane is expected to be 16 orders of magnitude greater than it is on our brane....
For whatever it's worth, a short note that Dr. White and Paul March both have invoked a (4+1) brane of spacetime in their explanation and papers.
Yes, I noticed that. Though I didn't follow why they did so, it seemed disconnected to me. I thought they referred to a 3+1 space, but if they used 4+1 then they included time. I'm more inclined to use 3+1 and set time aside.
Make a laser diode of appropriate shape with no exit. edit: fibre lasers could be of interest as well. You can make tapered fibre.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
...
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
I suspect it is quite difficult to build something with the required properties in laser wavelengths.
...
Of course frequency has an effect on thrust. Dumb statement for me to make as I only considered Df in a fixed frustum. Was thinking about my Flight Thruster design simulator, which did have a fixed Q of 50,000 at 3.85GHz but not anymore.
Thanks for that input. "Click" another piece of the puzzle drops into place.
It should be pointed out that this Shawyer thrust equationTo make F frequency (w) dependent you had to perform a variable substitution.
1) F = 2 Df Po Q / c
has been rejected by the physics community. Their version is
2) F = 0.
Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.
But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes
3) F = (2 E/c) w
and thus thrust scales linearly with frequency, and linearly with the stored energy.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.
Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.
Thus the Mettler should detect thrust for Q > 100.
This is usually far exceeded by optical cavities, which can have Qs up in the millions.
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
Shawyer states that the cavity reflectors must be half a wavelength apart, which might be a bit fiddly at laser frequencies.
Indeed you are correct, because eqn 3 suppresses the possible frequency dependence of E.In any vibration problem one can express Q as 2*Pi*f*EnergyStored/PowerLoss (it can be a mechanical vibration).
So let's go with thrust not being frequency dependent. That means that far higher thrust-to-weight ratios can be expected at higher frequencies.
And in that vein, I like the idea of a fully self-contained tapered fibre laser.
Indeed you are correct, because eqn 3 suppresses the possible frequency dependence of E.
So let's go with thrust not being frequency dependent. That means that far higher thrust-to-weight ratios can be expected at higher frequencies.
And in that vein, I like the idea of a fully self-contained tapered fibre laser.
It would weigh next to nothing - the battery would be most of the weight.
It should be pointed out that this Shawyer thrust equation
1) F = 2 Df Po Q / c
has been rejected by the physics community. Their version is
2) F = 0.
Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.
But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes
3) F = (2 E/c) w
and thus thrust scales linearly with frequency, and linearly with the stored energy.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.
Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.
Thus the Mettler should detect thrust for Q > 100.
This is usually far exceeded by optical cavities, which can have Qs up in the millions.
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
It should be pointed out that this Shawyer thrust equation
1) F = 2 Df Po Q / c
has been rejected by the physics community. Their version is
2) F = 0.
Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.
But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes
3) F = (2 E/c) w
and thus thrust scales linearly with frequency, and linearly with the stored energy.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.
The whole thing weighs probably about 50 gm (SWAG).
That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.
Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.
Thus the Mettler should detect thrust for Q > 100.
This is usually far exceeded by optical cavities, which can have Qs up in the millions.
So this experiment is expected to easily detect thrust from this little device.
Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.
If Shawyer is correct, that is.
More accurately, F = (2 Df Po Q / c) * D, where D is the Duty Cycle of the output. IF it were to put out thrust continuously at this value of F, CoE would be violated, because you are only putting in Po*t, not Q*Po*t. It takes time to store energy, and once it is stored, it can only deliver thrust for a limited amount of time before it needs to be recharged again. So there is a duty cycle associated with this thing that is being ignored.
Personally, I do not find Shawyer's equation to be that far off. I agree, his theory is flawed if you consider only perfectly conducting walls and group velocity. But, given asymmetrical losses, his assumption that F2 - F1 > 0 is exactly what it is. Two forces that are not exactly equal, opposing each other. The "how and why" are debatable, but the reality of it is not. Had someone done a Buckingham Pie Theory analysis of this, just based on input variables, the Max. potential thrust, 2*Q*P/c multiplied by an unknown Df based on the geometry, and whose value is to be experimentally determined, is exactly what you should get.
Todd D.
...Personally, I do not find Shawyer's equation to be that far off. I agree, his theory is flawed if you consider only perfectly conducting walls and group velocity. But, given asymmetrical losses, his assumption that F2 - F1 > 0 is exactly what it is. Two forces that are not exactly equal, opposing each other. The "how and why" are debatable, but the reality of it is not. Had someone done a Buckingham Pie Theory analysis of this, just based on input variables, the Max. potential thrust, 2*Q*P/c multiplied by an unknown Df based on the geometry, and whose value is to be experimentally determined, is exactly what you should get.Right on !
Todd D.
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.
Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Guess you have not read the Chinese data:
http://www.emdrive.com/NWPU2010translation.pdf
http://www.emdrive.com/NWPU2010testresults.pdf
http://www.emdrive.com/yang-juan-paper-2012.pdf
The thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
as a quick way to dismiss their results.
A.single paper is not a magic wand which causes all previous results to disappear. It cannot chan ge the tens of thousands of previous measure ments that have taken place in the last 50years. How do you refute cavities in pillbox shape that are used in GPS satellite atomic clocks? These have been characterized down to sub nanowatt levels, and no mystery power draw is observed and no thrust is observed in the GPS satellites (the location of which must be known very well.)
I don't refute the past nor existing devices as you should not. However that does not say they are all that is possible or that we know all possible variations of the theories thus embodied.
There is not a single paper, there are many.
Before signing a license deal with SPR, involving both the US and UK governments, Boeing would have crawled all over the SPR, all their devices, test rigs and especially the Demonstrator Engine and its static and dynamic test rigs. As part of that license deal, SPR built, tested and shipped the Flight Thruster to Boeing. SPR's claims for the results of the Flight Thruster are well known to Boeing. Never heard Boeing claim the Flight Thruster did not meet contract conditions.
BTW on the EagleWorks slide showing the various SPR devices, the Flight Thruster is labelled as a "High Fidelity Test Article". As the slide is from NASA. I'm sure SPR did not write that on the slide.
Just maybe something is happening that is inside the existing theories, yet largely unrealised. Both the Chinese and SPR state no new physics is needed and both CofE and CofM are conserved. Their theory math supports their claims and as well the theory math predicts the thrust they measured in 3 different ways.
...
It has not been ignored.
Sgawyer has discussed the TC and time to recharge the cavity energy lost to kinetic.
His superconducting space plane uses 8 EM Drives, arranged like 2 side by side 4 cylinder inline motors, driven in short pulses of less than 1 TC and phased apart to deliver continuous thrust.
Any portion of an atomic clock has been characterized to a degree many magnitudes greater than any of these test setups demonstrate. Just ask NIST. Unexpected results that have a divergence of the magnitude the papers you posted have claimed would have been identified during their development.
If you so strongly believe that these are happening, the timing on the GPS satellites have no correction for the effects observed from Eagleworks and the Chinese lab. Therefore, you should not use GPS receivers or trust any computer time that receives its time from NIST (basically most computers connected to the internet) until this 'new physics' is characterized. Because it would have a huge effect on those calculations.
And in other news, our Roumanian pal Iulian has gone silent.Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report :)
...
And in other news, our Roumanian pal Iulian has gone silent.Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report :)
...
Just to disambiguate that, if I may - he was asked a few times to rotate it to an upside down orientation once.And in other news, our Roumanian pal Iulian has gone silent.Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report :)
...
he could have hurt himself. he was using no protection and was asked to rotate the thing a few times.
I was wondering if we would be able to get a faster turnaround with prototyping and maybe even cut costs if we could use 3D printing and e.g. conductive graphene filament like this one:
We could share computer designs and use local 3D printing services. Would that work?
That's what I've been planning on doing. Makes construction a great deal simpler for some of the pieces. I'm getting the bottom plate printed in aluminum and I will drill and tap the bolt holes myself. This makes it much easier to create the spherical concave surface.
Which is to say that you've missed the point being made about GPS systems.
Which is to say that you've missed the point being made about GPS systems.
No, not really. We have to correct for relativistic effects, but still have a margin of error.
Fun fact: the GPS satellites all gave gamma ray detectors on them.
It doesn't matter what Boeing or SPR does, they can't change physics.
Any portion of an atomic clock has been characterized to a degree many magnitudes greater than any of these test setups demonstrate. Just ask NIST. Unexpected results that have a divergence of the magnitude the papers you posted have claimed would have been identified during their development.
If you so strongly believe that these are happening, the timing on the GPS satellites have no correction for the effects observed from Eagleworks and the Chinese lab. Therefore, you should not use GPS receivers or trust any computer time that receives its time from NIST (basically most computers connected to the internet) until this 'new physics' is characterized. Because it would have a huge effect on those calculations.
Which is to say that you've missed the point being made about GPS systems.
No, not really. We have to correct for relativistic effects, but still have a margin of error.
Fun fact: the GPS satellites all gave gamma ray detectors on them.
This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
The engine was built to operate at 2.45 GHz, with a design factor of 0.844 and has measured Q of 45,000 for an overall diameter of 280 mm.(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
That is a really impressive job!
I have recalculated the small diameter, using Shawyer's paper http://www.emdrive.com/IAC-08-C4-4-7.pdf, see page 7, where Shawyer statesQuote from: ShawyerThe engine was built to operate at 2.45 GHz, with a design factor of 0.844 and has measured Q of 45,000 for an overall diameter of 280 mm.(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
I have used this information
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
Design Factor = 0.844,
and inverted the equation for the Design Factor (see: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) to obtain the following correct dimension:
small diameter = 0.09613 m
Therefore, the dimensions should be corrected as follows
rfFrequency=2.45*10^9;
cavityLength=0.345; (ESTIMATED from Photographs)
bigDiameter=0.28 m; (provided by Shawyer)
smallDiameter= 0.09613 m; (obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
I was one of a few people trying to guestimate the small diameter of Shawyer's Demo. Yes, it was done by eye, or using tools attempting to match the profile of the cavity, which was by eye. For the error in small diameter you should fine a corresponding error in height as the taper is easy to match and the big diameter is given. These estimates were made before we had looked into the design factor so that approach wasn't considered. Neither did we have a good handle on cut-off or guide frequency. Time marches on, and you have somewhat better information now.
I suggest you go with the design factor calculation and adjust the height accordingly using the taper and the large and small diameters to calculate height. That is, of course if the numbers you derive will fit within the cavity as illustrated by the photographs. That is a simple sanity check. Others may have different and better justified opinions.
Asymmetry 101.
Throw a ball in the +x direction, perfect reflection from the front wall to hit the rear wall and be absorbed.
Throw: -p to floor through feet
Bounce: +2p to front wall
Absorb: -p to rear wall
Sum of momenta = 0
Conclusion: asymmetry doesn't make floobie dust.
This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
can someone explain in normal people terms were is the recoil going from turning on the microwave?
shouldn't the metal box push on the microwave just as much as the microwave pushes on the metal box?
also, it gets really hot... could the recoil just be delayed?
can someone explain in normal people terms were is the recoil going from turning on the microwave?
shouldn't the metal box push on the microwave just as much as the microwave pushes on the metal box?
also, it gets really hot... could the recoil just be delayed?
A 160 mm diameter experimental thruster, operating at 2.45 GHz was designed and built. (see fig 6) The design factor, calculated from as-built measurements of the thruster geometry(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
was 0.497. An unloaded Q of 5,900 was measured. [/b].
can someone explain in normal people terms were is the recoil going from turning on the microwave?
shouldn't the metal box push on the microwave just as much as the microwave pushes on the metal box?
also, it gets really hot... could the recoil just be delayed?
Shawyer's explanation is that the waves bounce back and forth across the device.
The speed of the waves depends upon the shape of the container (the container is acting as a wave-guide, which reduces the propagation speed to be less than C). Shawyer asserts that the momentum change is thereby asymmetric, due to the differing effective impact speeds. Note that the wider physics community do not agree with this analysis, although I do not understand the details.
However, there are other theories, in particular Dr.White at NASA thinks that the EM fields from the standing waves are interacting with quantum 'virtual particles', effectively pushing off these. There are problems to do with special relativity and conservation of energy that would seem to make this unlikely unless you go and revive some very old theories of the aether and absolute reference frames, which are very marginal (special relativity has been well tested and aether theories abandoned as unproductive).
Another theory that allows breaking of local conservation of momentum and which _is consistent with observations is Woodward 'Mach' effects. These relate to accelerating bodies which are changing in internal energy levels. The momentum is effectively transferred to all other bodies in the universe, at the speed of light. Attempts to produce or measure Mach effects have thus far failed, but there are reasonable theoretic reasons to believe they might be possible (they help to explain inertia and provide a preferred reference frame which special relativity lacks). I don't think anyone is explaining the EM drive in terms of this, however.
I have recalculated the small diameter, for Shawyer's EXPERIMENTAL THRUSTER using Shawyer's paper http://www.emdrive.com/IAC-08-C4-4-7.pdf, see page 6, where Shawyer statesQuote from: ShawyerA 160 mm diameter experimental thruster, operating at 2.45 GHz was designed and built. (see fig 6) The design factor, calculated from as-built measurements of the thruster geometry(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
was 0.497. An unloaded Q of 5,900 was measured. [/b].
I have used this information
bigDiameter = 0.16 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
Design Factor = 0.497,
and inverted the equation for the Design Factor (see: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) to obtain the following correct dimension:
small diameter = 0.1025 m SHAWYER's EXPERIMENTAL THRUSTER
(obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
Ha, that table was from you - "Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser."
Notice that while our original interpretation of Shawyer's Design Factor took into account all vital dimensions: the small diameter, the big diameter and the cavity length (from which the truncated cone angle can be obtained), the latest interpretation of Shawyer's Design Factor, completely ignores the cavity length. This interpretation of the Design Factor, worked out with TheTraveller shows that Shawyer calculates the thrust force on an EM Drive to be completely independent of the cavity length: it doesn't make a difference whether the cavity has zero length or whether the cavity has a length of 50,000 light years from here to the nearest magnetar. It doesn't make a difference whether the truncated cone has a cone angle approaching zero (like a cylinder) or the truncated cone has a cone angle of 45 degrees. While such a Design Factor, and hence such a formula for thrust force, that completely ignores the cavity length does not make physical sense to me, we have reproduced it, because if that is the formula that Shawyer used (however questionable it may be), that is the formula we need to unlock the geometrical dimension of the small diameter that Shawyer has not directly, explicitly provided. Please note that Shawyer has not provided the length of the cavity either, which is consistent with his formula that ignores the cavity length. Therefore, notice that Shawyer's cavity lengths are being estimated and so anyone using them is forewarned to use them at their own peril.
...Sir @TheTraveller, I was answering @phaseshift: I referred exclusively to Shawyer's mathematical equations, and the fact that the geometrical dimensions of the experiments where not reported in his papers. It is expected that the geometrical dimensions should be disclosed in experimental papers, and it is pro forma in peer-review to argue mathematical equations in papers.
It is not correct to state Shawyer ignores the length. He has stated many times that the applied Rf must cause frustum length resonance. Without this resonance there will be little thrust.
I understand you focus on the equations but maybe spend some time reading his words as per the attached.
Has he described how to calc the end plate separation versus external Rf to obtain resonance? No he has not.
Is that a crime? No it is not.
SPR is in business to make money and giving away all their "Secret Squirrel Secret Sauce" may not be in their best interest.
If Shawyer does not fully disclose, that is his right and you have NO right to call him out for doing so.
...Sir, I referred exclusively to Shawyer's mathematical equations, and the fact that the geometrical dimensions of the experiments where not reported in his papers. It is expected that the geometrical dimensions should be disclosed in experimental papers, and it is pro forma in peer-review to argue mathematical equations in papers.
It is not correct to state Shawyer ignores the length. He has stated many times that the applied Rf must cause frustum length resonance. Without this resonance there will be little thrust.
I understand you focus on the equations but maybe spend some time reading his words as per the attached.
Has he described how to calc the end plate separation versus external Rf to obtain resonance? No he has not.
Is that a crime? No it is not.
SPR is in business to make money and giving away all their "Secret Squirrel Secret Sauce" may not be in their best interest.
If Shawyer does not fully disclose, that is his right and you have NO right to call him out for doing so.
Sir, this thread is not a thread to deal with personalities, and much less is a thread to defend the business interests of personalities.
Please try to adopt an objective, and skeptical attitude in analyzing the EM Drive technical subject and try not to personalize it.
[...Incorrect. Read again. I stated that your interpretation of Shawyer's Design Factor ignores the cavity length.
You made statements Shawyer ignores the length. That statement is not correct.
You made statements Shawyer has not fully disclosed data. That is his right.
the latest interpretation of Shawyer's Design Factor, completely ignores the cavity length.
3D Plot of Shawyer's Design Factor vs. frequency and vs. small diameter; for same big diameter as Flight Thruster, but with the small diameter ranging from zero to same size as big diameter.
Remember: according to Shawyer the Design Factor multiplies the Power Input and the Q. The higher the Design Factor, the higher the thrust of the EM Drive, the smaller the Design Factor, the smaller the thrust.
Observe that at high frequency, the Design Factor changes almost linearly with small diameter, such that the Design Factor goes to zero as the small diameter approaches the big diameter.
The Design Factor approaches 1 for the small diameter approaching zero.
As the small diameter approaches zero, the cut-off frequency clips the Design Factor, such that to be able to have a smaller small diameter one has to operate at higher frequency (in order to avoid cut-off).
A very nice feature of Shawyer's Design Factor (as opposed to McCulloch's formula) is that Shawyer's Design Factor incorporates the cut-off frequency and hence it prevents consideration of a pointy cone, as the cut-off prevents too small of a small diameter to be considered.
The highest value of the Design Factor is reached at frequencies just a little over the cut-off frequency for the small end:
Cut-Off frequency for small end= cM/(cst*sD)
where
sD= small end diameter (m)
cst=1.7062895542683174
cM = light speed in selected medium (m/s)
= 299705000 (m/s) (speed of light in air)
= 299792458 (m/s) (speed of light in vacuum)
The Design Factor has little dependence on frequency, except near the cut-off frequency. The Design Factor of Shawyer asymptotically approaches this value for high frequencies (it becomes practically independent of frequency)
Limit[DesignFactor, f -> Infinity] = (bD^2 - sD^2)/(bD^2 + sD^2)
where
bD = big end diameter (m)
sD= small end diameter (m)
Whether Shawyer's Design Factor is correct, remains to be proven. For example, Shawyer's Design Factor predicts that the smaller the small diameter the better (hence larger cone angles, for constant frustum length), in contrast with Todd's conjecture that the highest attenuation the better (which leads to small cone angles ~7.5 degrees as the optimal design).
Reference: formula for Design Factor here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110
designFactor =
(bD^2 - sD^2)/( (bD^2)*Sqrt[1 - (cM/(bD*cst*f))^2] + (sD ^2)*Sqrt[1 - (cM/(cst*f*sD))^2] )
bD = big end diameter (m)
sD= small end diameter (m)
f = applied frequency (Hz)
cst=1.7062895542683174
cM = light speed in selected medium (m/s)
= 299705000 (m/s) (speed of light in air)
= 299792458 (m/s) (speed of light in vacuum)
Very interesting plot. Was working Excel to do the same, but why reinvent the wheel? Nice data.
One element we have yet to nut out is external applied Rf cavity resonance between the 2 end plates. Is vital for this to happen, as without resonance to applied Rf frequency, there will be no thrust developed as Q will be very low.
Simple to calc wavelength 1/2 wavelength between and call it done but with constantly variable guide wavelength between the end plates, my gut says end plate resonance is not 1/2 of Lambda0 (free) as Lambda0 only exists outside the cavity, nor Lambda1 (big end) guide wavelength nor Lambda2 (small end) guide wavelength. Additionally guide wavelength varies continuously, at each point of diameter change, from one end of the cavity to the other.
So how to calc the external Rf frequency required to bring the cavity into end plate to end plate resonance and allow Q to grow very large?
Of course all this assumes any external waveguide / coax is tuned (SWR 1:1) to supply Rf energy with minimal loss.
It is important as Shawyer says in the 1st attachment.
In the 2nd attachment there is notes an interesting object built into the side of the cavity.
It is used as in the 3rd attachment to assist the cavity getting into resonance?
[...Incorrect. Read again. I stated that your interpretation of Shawyer's Design Factor ignores the cavity length.
You made statements Shawyer ignores the length. That statement is not correct.
You made statements Shawyer has not fully disclosed data. That is his right.
I wrote: Shawyer's Design Factor, completely ignores the cavity length.
While such a Design Factor, and hence such a formula for thrust force, that completely ignores the cavity length
...It is known that the criitcal parameter in the solution of a conical cavity is the cone angle. It is obvious that Shawyer's Design Factor does not take into account the cone angle. As I stated in the note to my post ( http://forum.nasaspaceflight.com/index.php?topic=36313.msg1376840#msg1376840 ), since the initial cone angles of the experiments by Shawyer (the Experimental. Demonstration and Flight Thruster) involved small cone angles, according to the published photographs, it is apparent that Shawyer's thrust formula, and hence his Design Factor must be based on a small cone angle approximation.
T = (2 * Po * Df * Q) / c seems to ignore the requirement that the applied Rf must cause the frustum to operate in electrical length resonance. But in reality it is there.
Po does imply the frustum is operating at resonance as otherwise little energy would be transferred from the Rf generator to inside the frustum. Additionally the frustum load impedance must be matched to that of the Rf generator's output impedance or energy will be lost in the xfer.
Likewise for Q as using a Rf driving frequency that was not at frustum resonance would generate a low Q.
Which says both Shawyers Po and Q imply the frustum is impedance matched to the Rf generator and operating at length resonance with the driving Rf generator.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
...It is known that the criitcal parameter in the solution of a conical cavity is the cone angle. It is obvious that Shawyer's Design Factor does not take into account the cone angle. As I stated in the note to my original post, since the initial cone angles of the experiments by Shawyer (the Experimental. Demonstration and Flight Thruster) involved small cone angles, according to the published photographs, it is apparent that Shawyer's thrust formula, and hence his Design Factor must be based on a small cone angle approximation.
T = (2 * Po * Df * Q) / c seems to ignore the requirement that the applied Rf must cause the frustum to operate in electrical length resonance. But in reality it is there.
Po does imply the frustum is operating at resonance as otherwise little energy would be transferred from the Rf generator to inside the frustum. Additionally the frustum load impedance must be matched to that of the Rf generator's output impedance or energy will be lost in the xfer.
Likewise for Q as using a Rf driving frequency that was not at frustum resonance would generate a low Q.
Which says both Shawyers Po and Q imply the frustum is impedance matched to the Rf generator and operating at length resonance with the driving Rf generator.
can someone explain in normal people terms were is the recoil going from turning on the microwave?
shouldn't the metal box push on the microwave just as much as the microwave pushes on the metal box?
also, it gets really hot... could the recoil just be delayed?
Shawyer's explanation is that the waves bounce back and forth across the device.
The speed of the waves depends upon the shape of the container (the container is acting as a wave-guide, which reduces the propagation speed to be less than C). Shawyer asserts that the momentum change is thereby asymmetric, due to the differing effective impact speeds. Note that the wider physics community do not agree with this analysis, although I do not understand the details.
However, there are other theories, in particular Dr.White at NASA thinks that the EM fields from the standing waves are interacting with quantum 'virtual particles', effectively pushing off these. There are problems to do with special relativity and conservation of energy that would seem to make this unlikely unless you go and revive some very old theories of the aether and absolute reference frames, which are very marginal (special relativity has been well tested and aether theories abandoned as unproductive).
Another theory that allows breaking of local conservation of momentum and which _is consistent with observations is Woodward 'Mach' effects. These relate to accelerating bodies which are changing in internal energy levels. The momentum is effectively transferred to all other bodies in the universe, at the speed of light. Attempts to produce or measure Mach effects have thus far failed, but there are reasonable theoretic reasons to believe they might be possible (they help to explain inertia and provide a preferred reference frame which special relativity lacks). I don't think anyone is explaining the EM drive in terms of this, however.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
can someone explain in normal people terms were is the recoil going from turning on the microwave?
shouldn't the metal box push on the microwave just as much as the microwave pushes on the metal box?
also, it gets really hot... could the recoil just be delayed?
Shawyer's explanation is that the waves bounce back and forth across the device.
The speed of the waves depends upon the shape of the container (the container is acting as a wave-guide, which reduces the propagation speed to be less than C). Shawyer asserts that the momentum change is thereby asymmetric, due to the differing effective impact speeds. Note that the wider physics community do not agree with this analysis, although I do not understand the details.
However, there are other theories, in particular Dr.White at NASA thinks that the EM fields from the standing waves are interacting with quantum 'virtual particles', effectively pushing off these. There are problems to do with special relativity and conservation of energy that would seem to make this unlikely unless you go and revive some very old theories of the aether and absolute reference frames, which are very marginal (special relativity has been well tested and aether theories abandoned as unproductive).
Another theory that allows breaking of local conservation of momentum and which _is consistent with observations is Woodward 'Mach' effects. These relate to accelerating bodies which are changing in internal energy levels. The momentum is effectively transferred to all other bodies in the universe, at the speed of light. Attempts to produce or measure Mach effects have thus far failed, but there are reasonable theoretic reasons to believe they might be possible (they help to explain inertia and provide a preferred reference frame which special relativity lacks). I don't think anyone is explaining the EM drive in terms of this, however.
My personal preference goes to the "Todd conjecture"... :) (poke poke)
This theory, developped by Warptech (aka Todd D) formulates that due to the shape of the cone, waves slow down towards the small end (compression?). As a consequence, the fall in speed is compensated by a change in frequency, causing them to fall out of resonance (between small en big plate). So they and up being attenuated or cut. The energy/momentum of that wave can't just vanish, but it is transferred into the frustum walls...
dunno if I formulated it 100% correctly, but that's how I understood the idea.. more or less... sort of... :)
I like this idea because it gives a very comprehensible way to explain where the momentum of the frustum comes from. Something I really miss in all the other theories.
Quantum Vacuum field? dunno, but feels more like an artificial mathematical model that attempts to explain, then a valid theory to explain something real. QV has yet to be proven by experiments, btw...
However, it would also mean that the pursuit of a higher Q, to achieve higher performances is a dead end.
If Shawyer can prove with his supercooled rig that he is indeed getting considerable thrust improvements, then this theory goes down the drain...
So far, little news has been brought on his nitrogen cooled device.. tbh, that worries me a little. I'll admit, I've never believed Shawyer's linear extrapolations that promise 1ton of thrust. I know very few devices that scale perfectly linear in power/thrust output.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect.
It would be interesting to see which cylindrical cavity mode gave the greatest integrated field along a given laser beam path. As far as detection goes, there has been great progress lately on separating out small sidebands from an intense laser line. (i'll look into that)
QuoteWarptech
If the thruster had 2 compartments, a cylinder, where resonance was easy to establish at high Q, and a long frustum designed for maximum attenuation connected at one end of the cylinder. Between the two, there is a "shutter" that can rapidly open and close. When closed, the cylinder resonates as a cylinder. When open, energy expands into the frustum chamber where it is attenuated. After the shutter closes again, the energy in frustum attenuates and energy in cylinder recharges.... repeat. I keep looking for ways to decouple the resonant amplifier from the attenuator.
Firstly I need to ask what sort of timeframes you are looking at for connecting/ disconnecting cycle, micro_sec, milli_sec, seconds?.
How long do you think the coupling will need to be in place to create resonance inside the thruster cavity...{or are you thinking the resonance is not even needed in that chamber at all, just force fed from the attached cylinder in burst mode}. I think I see where you are going with this but more info may help clarify the desired method, and help refine a model im working on for mechanical distribution of em waves.
But what happens when a wave is attenuated in a perfectly conducting circular waveguide? That energy is not lost as "heat" because there is no resistance to dissipate it.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect.
It would be interesting to see which cylindrical cavity mode gave the greatest integrated field along a given laser beam path. As far as detection goes, there has been great progress lately on separating out small sidebands from an intense laser line. (i'll look into that)
Do you mean shooting a laser beam into a cylindrical cavity or into a frustum?
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect.
It would be interesting to see which cylindrical cavity mode gave the greatest integrated field along a given laser beam path. As far as detection goes, there has been great progress lately on separating out small sidebands from an intense laser line. (i'll look into that)
Do you mean shooting a laser beam into a cylindrical cavity or into a frustum?
Just cylindrical at this point.
"Bessel function - magnetron - (SRF) superconducting RF cavity - Fermi Labs"
Sound interesting? I thought so: http://www.fnal.gov/pub/today/archive/archive_2014/today14-11-03.html
Should the emdrive become a reality...Fermi might be on the verge of helping to develop a massive, cost-effective RF source: http://www.fnal.gov/pub/today/archive/archive_2014/images/magnetron.jpg
The reason I'm not retired is that I want to build this prototype," Pasquinelli said. "It's a solution to a real-world problem, and it will be a lot of fun to build the first one.
But what happens when a wave is attenuated in a perfectly conducting circular waveguide? That energy is not lost as "heat" because there is no resistance to dissipate it.
How will the wave attenuate (lose energy) if no wall losses?
Hi,Welcome to the forum :)
Here's another first post from someone who's been reading this thread for a long time.
...
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.Thank you for an interesting paper. What I think would be helpful for anchoring the reader in reality would be a small worked example for the thrust prediction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect.
I've posted the files (both original Solidworks .SLDPRT and printable .STLs) on Thingiverse for anyone that wants a copy (link: http://www.thingiverse.com/thing:838001). If I get time over the next few days/weeks I'm going to try and make it easier to build, break it down into more parts, tabulate the dimensions to make it easier to modify, and maybe add some proper drawings.
VIVA ITALIA......
Incidentally, since we had a "Yay for Romania!" moment in this thread for Iulian's work, may I (as an Italian expat) have a "Yay for Italy!" moment for Marco's work? :)
By the way.. where is Iulian? I hope he has not crippled or killed himself with the magnetron.. !
By the way.. where is Iulian? I hope he has not crippled or killed himself with the magnetron.. !
Similar concerns about him have been raised elsewhere. Hope he's OK.
Besides the obvious dangers associated with microwaves, there is the non-obvious danger of Beryllium inhalation if it gets chipped and it becomes airborne.By the way.. where is Iulian? I hope he has not crippled or killed himself with the magnetron.. !
Similar concerns about him have been raised elsewhere. Hope he's OK.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.*Cherry picks the points and takes in the formulas . . . very slowly.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
I've posted the files (both original Solidworks .SLDPRT and printable .STLs) on Thingiverse for anyone that wants a copy (link: http://www.thingiverse.com/thing:838001). If I get time over the next few days/weeks I'm going to try and make it easier to build, break it down into more parts, tabulate the dimensions to make it easier to modify, and maybe add some proper drawings.
Welcome to the forum! ;D It's great here!
Not to put words under your fingers, but it sounds like you're making something of your own template for EM drive home builds. As another none-expert interested in having a shot at it, I tip my proverbial hat to you.
I thought we had (x for lambda)
x02 = x1 x2
but here you say
x12 = x0 x2
which of course is not the same
where x0 is the input RF wavelength
That table (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1302455#msg1302455 ) was dated 12/14/2014, more than 5 months ago.
The table was the result of the best efforts of a team of people that have been in this thread from the beginning, working with this "EM Drive tar baby" where researchers report experimental measurements without giving the dimensions of the cavities used in the experiments .
That table (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1302455#msg1302455 ) was dated 12/14/2014, more than 5 months ago.
The table was the result of the best efforts of a team of people that have been in this thread from the beginning, working with this "EM Drive tar baby" where researchers report experimental measurements without giving the dimensions of the cavities used in the experiments .
This data is some of the most-referenced in the entire thread. To make it easier to read, I reformatted it into this page on the wiki (http://emdrive.echothis.com/Dimensions). As the estimated dimensions and other parameters are revised, and tests run on new device variations, they can easily be updated there.
In addition if there is other content that should be replicated there (I'm thinking of theory equations and derivations in particular), let me know - or just jump in yourself. The wiki now supports MathJax (https://www.mathjax.org/) so the math there can be more readable than what we can do in a forum post.
Any other comments on how to make the wiki more useful, please PM me. It's been averaging a few updates a day by various folks, so is starting to grow.
-Rolf
Besides the obvious dangers associated with microwaves, there is the non-obvious danger of Beryllium inhalation if it gets chipped and it becomes airborne.By the way.. where is Iulian? I hope he has not crippled or killed himself with the magnetron.. !
Similar concerns about him have been raised elsewhere. Hope he's OK.
https://www.youtube.com/watch?v=cGZsGN8PzU4
http://en.wikipedia.org/wiki/Beryllium_poisoning
...Excellent question that has been puzzling me for a long time as well. To examine this, first let's recapitulate the statement in Brady et.al.' report:
Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!
There appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF resonator in the thrust chamber. The geometry, location, and material properties of this resonator must be evaluated using numerous COMSOL® iterations to arrive at a viable thruster solution. We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust
(Shawyer and the Chinese used the magnetron excited TE012 mode in their frustum cavities without dielectrics being present.)
That table (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1302455#msg1302455 ) was dated 12/14/2014, more than 5 months ago.
The table was the result of the best efforts of a team of people that have been in this thread from the beginning, working with this "EM Drive tar baby" where researchers report experimental measurements without giving the dimensions of the cavities used in the experiments .
This data is some of the most-referenced in the entire thread. To make it easier to read, I reformatted it into this page on the wiki (http://emdrive.echothis.com/Dimensions). As the estimated dimensions and other parameters are revised, and tests run on new device variations, they can easily be updated there.
In addition if there is other content that should be replicated there (I'm thinking of theory equations and derivations in particular), let me know - or just jump in yourself. The wiki now supports MathJax (https://www.mathjax.org/) so the math there can be more readable than what we can do in a forum post.
Any other comments on how to make the wiki more useful, please PM me. It's been averaging a few updates a day by various folks, so is starting to grow.
-Rolf
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.*Cherry picks the points and takes in the formulas . . . very slowly.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
This is worth a hot tub print out and read. Kudos to you. My math is quite rusty but I still have enough stocked away to grasp what your inferring and so far it makes some good sense.
Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect....
Even if the thrust was not macroscopic, ...
...
But what happens when a wave is attenuated in a perfectly conducting circular waveguide? That energy is not lost as "heat" because there is no resistance to dissipate it.
How will the wave attenuate (lose energy) if no wall losses?
I've been reading for several days, I have a question regarding the Maxwell Equations simulations of the Frustrum.
I recently read a paper by Tuval and Yahalom (2013). They note that Maxwell's equations are conservative of momentum if the action of forces is taken to be instantaneous. However, if the forces are taken to be propagating at c they are not, in general, for particles. [The momentum of the fields is needed to make conservation of momentum work.]
So, the question is: do the simulations of the frustrum account for the retarded forces and fields on and created by the moving charges in the walls/end caps?
R.
Thanks. Yes, you are right. It is the next step to fill with numbers and put some plots to see the orders of magnitude. I am not sure yet that I am able to account for a macroscopic effect....
Even if the thrust was not macroscopic, ...
...
Ok, I've run some back-of-the-envelope calculations in pure engineer style, i.e. just looking at the orders of magnitude.
I am handwaving constants as follows:
pi^2 = 10^1
G = 10^-11
c^4 = 81 * 10^32 = 10^34
mu0^2 = 16 * pi^2 * 10^-14 = 10^-12
h = 1 (this is the height of the frustum, right? Not Planck!)
and I get that the geometry related effects have to counter-balance a term which is 10^-32 * U0^4.
At this point we are left with a term (1 / ln2(r2/r1)) * (r2^4 * XXX - (r2^6 / r1^2) * YYY), where XXX and YYY are those complicated expressions for the fourth power of the magnetic field that I can't rewrite here. :) But, out of the two terms the second one is clearly dominant if r2 >> r1.
So we're left with 10^-32 * U0^4 * YYY * (r2^6 / r1^2) * (1 / ln2(r2/r1)).
I can't quite follow what the order of magnitude of U0 and YYY would be. Can anybody help me? Are they going to be significant powers of ten?
Anyway, if we just want to balance that 10^-32, we need something like r2/r1 = 10^5.5, for example:
r2 = 10^2.5 = several hundred meters
r1 = 10^-3 = one millimeter
given a frustum height of just one meter... Things get better if h is small, but not too much better.
Not very encouraging in terms of practicality. :( And if U0 or YYY are going to be negative powers of ten, it's going to get even worse.
Damn gravity being such a weak force! :)
Anyway, if we just want to balance that 10^-32, we need something like r2/r1 = 10^5.5, for example:
r2 = 10^2.5 = several hundred meters
r1 = 10^-3 = one millimeter
given a frustum height of just one meter...
Anyway, if we just want to balance that 10^-32, we need something like r2/r1 = 10^5.5, for example:
r2 = 10^2.5 = several hundred meters
r1 = 10^-3 = one millimeter
given a frustum height of just one meter...
Gah! Sorry, big glaring error there in my last passage. :)
Because it's r2^6 / r1^2, I can't just consider r2/r1 and scale the ratio.
r2=10^5.5
r1=1
is a correct example.
Thanks for digging it out, I know you're more savvy with the search function than I am. I keep on coming back to this paper and this statement. Yes and I know the effects are very very small....Excellent question that has been puzzling me for a long time as well. To examine this, first let's recapitulate the statement in Brady et.al.' report:
Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!QuoteThere appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF resonator in the thrust chamber. The geometry, location, and material properties of this resonator must be evaluated using numerous COMSOL® iterations to arrive at a viable thruster solution. We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust
My exact solution for the truncated cone, given the dimensions reported by Paul March and also used in NASA's COMSOL FEA analysis, for mode shape TE012, gives me a natural frequency of:
2.2024 GHz
So they operated at frequency of 2.168 GHz which is 1.59% away from the frequency given by the exact solution. Perhaps the reason was that that was the frequency given by the Finite Element analysis for mode TE012 (let's recall that the Finite Element solution converges from below to the correct eigensolution, and only for an infinite Finite Element mesh one can theoretically converge to the eigensolution). So, they were looking in the right frequency range for TE012.
My recollection is that Paul March thought that the reason maybe that to generate thrust without a dielectric one needs to provide Amplitude, Frequency and Phase Modulation, and that at the time of the experiments detailed in the NASA report ( http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf ), they were not providing the needed AM, FM and PM modulation. I was not able to find the exact quotation (I wonder why, given the fantastic search function we have at this site ;) ). I was only able to find this quotation from Paul March, in answer to this question:Quote from: Star-Drive(Shawyer and the Chinese used the magnetron excited TE012 mode in their frustum cavities without dielectrics being present.)
...Having worked with polymers for decades, I agree that the extruded HDPE and PTFE (from McMaster Carr) that NASA Eagleworks used as dielectrics would be quite a stretch to be considered "strongly magneto-chiral", and be responsible for the measured thrust forces. Also, (I have not read those papers in a long time, so please point out whether I'm wrong in my assessment, which I'll appreciate to know) my recollection is that they had to resort to a 4th order term in a perturbation series of the nonlinear problem to get the term that they rely on for the claimed effect. My recollection is that they do not support what is the range of validity for that 4th order term to be significant, and it is also my recollection that the authors do not prove that the series in question (is it an asymptotic series ? ) is convergent and therefore whether the neglected higher order terms sum do not overwhelm the 4th order term they consider...
I honestly think we have a "physical" system in the EM Drive if we use magneto-chiral matter (HDPE is a weak one in the way the carbon atoms are layered). REF: http://www.nature.com/nmat/journal/v7/n9/full/nmat2256.html
Note here that we are choosing to work with the momentum density associated with the canonical energy momentum tensor rather than the Poynting vector; the latter is expected to integrate to zeroDoesn't that imply zero net thrust?
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
Certainly yes for a linear isotropic system, but apparently not for an anisotropic nonlinear system as the one they are considering. They are considering a 4th order term.QuoteNote here that we are choosing to work with the momentum density associated with the canonical energy momentum tensor rather than the Poynting vector; the latter is expected to integrate to zeroDoesn't that imply zero net thrust?
r2=10^5.5
r1=1
is a correct example.
It is my approximation: r2 increasingly large and r1 decreasing toward zero otherwise one should change the final formula. So, in your example it would be better to have r2=10 m and r1=10^-3 m and so on. This is a cone.
Another way around, as suggested above, is to fill with some material the cavity. The formula goes like mur^-2 and mur much smaller than 1.
I see it!Certainly yes for a linear isotropic system, but apparently not for an anisotropic nonlinear system as the one they are considering. They are considering a 4th order term.QuoteNote here that we are choosing to work with the momentum density associated with the canonical energy momentum tensor rather than the Poynting vector; the latter is expected to integrate to zeroDoesn't that imply zero net thrust?
Marco's present equations in his present papers are general enough to already include (in the limit for cone angle approaching zero) a cylindrical pillbox cavity as the one used by NASA in their actual experiments. We (in a previous post) actually considered such a shape, and it is clearly inferior to a pointy cone. The action takes place towards the apex of the cone. The pointy conical geometry is important for this effect. Notice that there is a singularity at a cone's vertex, we need some help like that from geometry, that I don't see in nice rounded shapes. Considering a material with different permeability I think that a material discontinuity interface (providing a jump rather than a gradual variation) is also helpful in this regards :)r2=10^5.5
r1=1
is a correct example.
It is my approximation: r2 increasingly large and r1 decreasing toward zero otherwise one should change the final formula. So, in your example it would be better to have r2=10 m and r1=10^-3 m and so on. This is a cone.
...
What if we considered other shapes? We started with the truncated cone because of the EmDrive, but what if we considered a pillbox cavity (which is basically a rounded cone...)? All the equations would be different, for sure, but it might be worth exploring. Maybe in another thread. :)
...
I'm incredibly appreciate of all the work that went into the dimensional estimates of the various drives but I'm having some difficulty understanding where the dimensional values came from regarding the attached image:I can't answer that beyond hypotheticals like 1) Shawyer's paper may have a typo in the numbers (a small difference in the DesignFactor makes a big difference in the dimensions for example), 2) TheTraveller's latest interpretation of the DesignFactor may still not be Shawyer's DesignFactor (which I repeat was not explicitly defined by Shawyer in his papers), 3) the picture you are using may not represent what Shawyer meant by the Demonstration engine in his paper, 4) the "length" is arbitrary for this design because the location of the internal movable wall at the small end is unknown (I don't know whether the guesstimator used the maximum length for example or the average length or the minimum length) etc. etc.
Shawyer reported a large plate diameter of .28m - so using that as a given.
Going straight off the image (not taking into account perspective) at the junction of the cone and the cylinder I get about .169m for the small plate diameter. This is a difference of 40mm with what was originally estimated and about 73mm from Dr. Rodal's calculation (96.13) of the small plate diameter. This is an enormous difference and I can't believe it. I'm going to model this and lay it on top of the photo in perspective so I can find out what the numbers are closer to.
Also the cone length was estimated to be .345m - which is larger than the plate diameter. Between which two points is this measurement for?
Consider the typical SRF cavities described in this paper: http://arxiv.org/pdf/physics/0003011.pdfIt's worse than that because the cavities are niobium-coated copper; copper has a yield strength of 70 MPa.
Each cell in the stack of cavities could be thought of as being two cones arranged back to back: <><><><> (see Figure 5). We would then expect any forces to try and pull the two half-cavities apart.
These were operated at 1.3 GHz, 200 kW CW RF, with a measured Q of ~ 5e9.
Applying the quoted formula of F ~ Po*Q/c, we get a force of 3e6 N.
The cavities have a wall thickness of about 2 mm, and a major radius of ~100 mm, giving a strain of > 2000 MPa in the niobium. The yield strength of niobium is somewhere in the range of 80-150 MPa, depending on temper and annealing. And yet the cavities did not fly apart.
Anyone care to poke holes in this?
Consider the typical SRF cavities described in this paper: http://arxiv.org/pdf/physics/0003011.pdfHoles:
Each cell in the stack of cavities could be thought of as being two cones arranged back to back: <><><><> (see Figure 5). We would then expect any forces to try and pull the two half-cavities apart.
These were operated at 1.3 GHz, 200 kW CW RF, with a measured Q of ~ 5e9.
Applying the quoted formula of F ~ Po*Q/c, we get a force of 3e6 N.
The cavities have a wall thickness of about 2 mm, and a major radius of ~100 mm, giving a strain of > 2000 MPa in the niobium. The yield strength of niobium is somewhere in the range of 80-150 MPa, depending on temper and annealing. And yet the cavities did not fly apart.
Anyone care to poke holes in this?
I'm incredibly appreciate of all the work that went into the dimensional estimates of the various drives but I'm having some difficulty understanding where the dimensional values came from regarding the attached image:That one was a challenge. Note the geared mechanism at the small end, end of the cylinder. It was considered that this mechanism drove a plunger that changed the length of the cavity in order to adjust the resonance frequency. Hence there needed to be some part of the diameter of the interior of the cylinder section devoted to supporting and guiding this plunger. How much was just a guess, but as I recall, I assumed that the actual small end of the resonant cavity was likely located about midway between the ends of the cylinder.
Shawyer reported a large plate diameter of .28m - so using that as a given.
Going straight off the image (not taking into account perspective) at the junction of the cone and the cylinder I get about .169m for the small plate diameter. This is a difference of 40mm with what was originally estimated and about 73mm from Dr. Rodal's calculation (96.13) of the small plate diameter. This is an enormous difference and I can't believe it. I'm going to model this and lay it on top of the photo in perspective so I can find out what the numbers are closer to.
Also the cone length was estimated to be .345m - which is larger than the plate diameter. Between which two points is this measurement for?
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
I like you paper but have a request for a point of clarification. I got really confused when you went from equation 55 to equation 56. Why did you invert the c4/G term? (Actually I got confused way before that but I won't go there. :)
r2=10^5.5
r1=1
is a correct example.
It is my approximation: r2 increasingly large and r1 decreasing toward zero otherwise one should change the final formula. So, in your example it would be better to have r2=10 m and r1=10^-3 m and so on. This is a cone.
Yes. But the dependence on r2 is stronger than the one on r1, because r2 is to the sixth power whereas r1 is just squared.
So: if you keep r1 constant and vary r2, you don't need many orders of magnitude to have a reasonable effect; if you keep r2 constant and vary r1, you need to go down a lot of orders of magnitude.
If we have an r2 of one meter, r1 must be 10^-16, which is a tenth of a femtometer, which is less than the size of a proton. We cannot possibly manufacture such a cone and I think it would not work anyway because the resulting "small end plate" doesn't have enough electrons to behave like an ideal EM-reflecting plate. Although maybe it doesn't need to and it's just the cavity shape that matters.
What if we considered other shapes? We started with the truncated cone because of the EmDrive, but what if we considered a pillbox cavity (which is basically a rounded cone...)? All the equations would be different, for sure, but it might be worth exploring. Maybe in another thread. :)Another way around, as suggested above, is to fill with some material the cavity. The formula goes like mur^-2 and mur much smaller than 1.
Yes, varying mu may be profitable too.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
I like you paper but have a request for a point of clarification. I got really confused when you went from equation 55 to equation 56. Why did you invert the c4/G term? (Actually I got confused way before that but I won't go there. :)
I have taken out a l0^-1 that so becomes l0^-2.
As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
I like you paper but have a request for a point of clarification. I got really confused when you went from equation 55 to equation 56. Why did you invert the c4/G term? (Actually I got confused way before that but I won't go there. :)
I have taken out a l0^-1 that so becomes l0^-2.
Sorry, but I still don't understand how that converts c4/G to (c4/G)-1.
I suspect that there is a transcription error somewhere, and that (c4/G)-1 was intended all along.
I'm incredibly appreciate of all the work that went into the dimensional estimates of the various drives but I'm having some difficulty understanding where the dimensional values came from regarding the attached image:
Shawyer reported a large plate diameter of .28m - so using that as a given.
Going straight off the image (not taking into account perspective) at the junction of the cone and the cylinder I get about .169m for the small plate diameter. This is a difference of 40mm with what was originally estimated and about 73mm from Dr. Rodal's calculation (96.13) of the small plate diameter. This is an enormous difference and I can't believe it. I'm going to model this and lay it on top of the photo in perspective so I can find out what the numbers are closer to.
Also the cone length was estimated to be .345m - which is greater than the large plate diameter. Between which two points is this measurement for?
Where did you (Rodal) get the design factor of .844 that you used in calculating the small diameter of .09613m?Take a gander again :) : I had meticulously answered that question in my message http://forum.nasaspaceflight.com/index.php?topic=36313.msg1376720#msg1376720 which you (phaseshift) quoted verbatim in your own message http://forum.nasaspaceflight.com/index.php?topic=36313.msg1376723#msg1376723
..Shawyer reported a large plate diameter of .28m - so using that as a given...No, it is even worse, using that value for the small diameter (0.17 m), the DesignFactor (calculated with this equation http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) is even smaller:
I'm almost certain that the small plate diameter is close to .17m. This produces a design factor of .5197. ...
smallDiameter = 0.17 m;
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
results in the following DesignFactor
Design Factor = 0.4853 (instead of the 0.5197 value you quoted above)
..Shawyer reported a large plate diameter of .28m - so using that as a given...No, it is even worse, using that value for the small diameter (0.17 m), the DesignFactor (calculated with this equation http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) is even smaller:
I'm almost certain that the small plate diameter is close to .17m. This produces a design factor of .5197. ...
smallDiameter = 0.17 m;
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
results in the following DesignFactor
Design Factor = 0.4853 (instead of the 0.5197 value you quoted above)
I can see people next stating that Shawyer just transposed the numbers: he meant to write..Shawyer reported a large plate diameter of .28m - so using that as a given...No, it is even worse, using that value for the small diameter (0.17 m), the DesignFactor (calculated with this equation http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) is even smaller:
I'm almost certain that the small plate diameter is close to .17m. This produces a design factor of .5197. ...
smallDiameter = 0.17 m;
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
results in the following DesignFactor
Design Factor = 0.4853 (instead of the 0.5197 value you quoted above)
Which is interesting given that his experimental thruster had a DF of .497. So I don't know if he incorrectly reported .844 or the equation is wrong. I can say for certain that the small plate diameter in the photo is not even close to 96mm - I couldn't be that much off with my eyes closed ;) lol
DesignFactor = 0.484 (which gives a sD = 0.17027 m)
but he wrote instead
DesignFactor =0.844 ;)
I suggest that we wait for the person who has read most of Shawyer's papers (TheTraveller). Perhaps TheTraveller can find another paper on the Demonstrator Engine by Shawyer besides the one I quoted, and check whether Shaywer quotes the same DesignFactor 0.844 or the more sensible number 0.484...
I can see people next stating that Shawyer just transposed the numbers: he meant to write
DesignFactor = 0.484 (which gives a sD = 0.17027 m)
but he wrote instead
DesignFactor =0.844 ;)
Yes, good possibility - I did the EXACT same thing about 10 minutes ago. :)
I suggest that we wait for the person who has read most of Shawyer's papers (TheTraveller). Perhaps TheTraveller can find another paper on the Demonstrator Engine by Shawyer besides the one I quoted, and check whether Shaywer quotes the same DesignFactor 0.844 or the more sensible number 0.484
Meanwhile, if you have the time and find it worthwhile to do so, perhaps you could ascertain whether the following dimensions make senseI suggest that we wait for the person who has read most of Shawyer's papers (TheTraveller). Perhaps TheTraveller can find another paper on the Demonstrator Engine by Shawyer besides the one I quoted, and check whether Shaywer quotes the same DesignFactor 0.844 or the more sensible number 0.484
This is my source: http://www.emdrive.com/IAC-08-C4-4-7.pdf
But then you have that U_0^4 that depends on Q^2 and P^2. As said before, I am not certain that I get a really macroscopic effect even if an interferometric device, sensible enough, can grant observation of the effect. I have to work out some numerics to see really what is going on. There is also the contribution coming from the square of the mode that can take the effect down.
Meanwhile, if you have the time and find it worthwhile to do so, perhaps you could ascertain whether the following dimensions make senseI suggest that we wait for the person who has read most of Shawyer's papers (TheTraveller). Perhaps TheTraveller can find another paper on the Demonstrator Engine by Shawyer besides the one I quoted, and check whether Shaywer quotes the same DesignFactor 0.844 or the more sensible number 0.484
This is my source: http://www.emdrive.com/IAC-08-C4-4-7.pdf
(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;(estimated from photographs)
bigDiameter=0.16; (given by Shawyer)
smallDiameter=0.1025; (obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
Design Factor = 0.497;
Regarding the Demo cavity dimensions - It would be very helpful if someone with knowledge and tools for image interpretation were to look at the Demo cavity as was done for the Flight thruster. In looking at the image again, it appears to me like there might be a cylinder section on both ends. The one on the small end is obvious but is there a short cylinder between the two flanges at the big end? And if so, why? Did Shawyer make his Demo thruster as two cylinders joined by a conic section?
Regarding the Demo cavity dimensions - It would be very helpful if someone with knowledge and tools for image interpretation were to look at the Demo cavity as was done for the Flight thruster. In looking at the image again, it appears to me like there might be a cylinder section on both ends. The one on the small end is obvious but is there a short cylinder between the two flanges at the big end? And if so, why? Did Shawyer make his Demo thruster as two cylinders joined by a conic section?
aero,
I considered that when analyzing the dimensions - you don't even need image processing software - look at the reflection of the "workbench" on the cylinder, then on the cone, then on the next 'cylinder'. It's rather obvious that it is a cylinder rather than more of the cone. I believe given the dimensions (thickness of this area), and the possibility of a concave surface on the large plate that the larger cylinder contains the large plate. For some reason, perhaps just because he was still figuring out construction methods, Shawyer did it this way rather than the fully external plate on the higher fidelity devices.
Regarding the Demo cavity dimensions - It would be very helpful if someone with knowledge and tools for image interpretation were to look at the Demo cavity as was done for the Flight thruster. In looking at the image again, it appears to me like there might be a cylinder section on both ends. The one on the small end is obvious but is there a short cylinder between the two flanges at the big end? And if so, why? Did Shawyer make his Demo thruster as two cylinders joined by a conic section?
aero,
I considered that when analyzing the dimensions - you don't even need image processing software - look at the reflection of the "workbench" on the cylinder, then on the cone, then on the next 'cylinder'. It's rather obvious that it is a cylinder rather than more of the cone. I believe given the dimensions (thickness of this area), and the possibility of a concave surface on the large plate that the larger cylinder contains the large plate. For some reason, perhaps just because he was still figuring out construction methods, Shawyer did it this way rather than the fully external plate on the higher fidelity devices.
Are you confirming that you think there are cylinders on both ends of the frustum section? If so, then how long is, (what is the height of), the big end cylinder (estimate). Then what is the height of the frustum section? Lastly, what is your estimate of the length of the small cylinder? That is, what is the overall electrical length of the EM thruster "Demo"?
Now, can these pieces be related to the terms used in Shawyer's design factor equation?
Yes, I am saying that there are two cylinders.Could you provide the link to the dimensions that you refer to? "See above" leaves a lot of room for me to choose the wrong post. And the length of the cylinder on the big end is kind of important if I were to model it with FDTD software (Meep), as is the length and radius of the small end cylinder and length of the frustum section. Not that I have any immediate plans to do so, but I might model it in 2D just for grins. It could be interesting to see what the wave forms might look like.
See above for dimensions. :) Those are the dimensions I got from the model - the thickness of the large plate is not terribly important - thick enough to contain a spherically concave surface if it is there. The small plate is at the end of the cone. Given the possibility of Shawyer mistyping his DF of .844 when it should have been .484 the numbers all work.
QuoteYes, I am saying that there are two cylinders.Could you provide the link to the dimensions that you refer to? "See above" leaves a lot of room for me to choose the wrong post. And the length of the cylinder on the big end is kind of important if I were to model it with FDTD software (Meep), as is the length and radius of the small end cylinder and length of the frustum section. Not that I have any immediate plans to do so, but I might model it in 2D just for grins. It could be interesting to see what the wave forms might look like.
See above for dimensions. :) Those are the dimensions I got from the model - the thickness of the large plate is not terribly important - thick enough to contain a spherically concave surface if it is there. The small plate is at the end of the cone. Given the possibility of Shawyer mistyping his DF of .844 when it should have been .484 the numbers all work.
I don't see any problem with the units the way they are in Eq. 55 and 56.As promised I am posting the latest draft about general relativity and electromagnetic field. The relevant conclusion is that there is thrust. Thanks to the comments by Jose Rodal, it can be shown that this can be meaningful and the best geometry is that of the frustum tending to a cone. There is no violation of conservation law due to the presence of the gravity that can escape the device producing a reaction.
I post it here for your comments that are very welcome as usual. You can find the final equation at page 12 for your evaluations. Later on, I will post a version with a somewhat different presentation to arxiv.
I like you paper but have a request for a point of clarification. I got really confused when you went from equation 55 to equation 56. Why did you invert the c4/G term? (Actually I got confused way before that but I won't go there. :)
I have taken out a l0^-1 that so becomes l0^-2.
Sorry, but I still don't understand how that converts c4/G to (c4/G)-1.
I suspect that there is a transcription error somewhere, and that (c4/G)-1 was intended all along.
Thanks for pointing out this. I will check all tomorrow. Please, consider that a term c^4/G is coming out from the construction of the tensor in eq.(46). I have checked physical dimensions step by step by I'll redo it for sure.
I guess the step between Eqn. 55 and Eqn 56 is just to large for me.
Warptech
<snip>
Ok
If Im following your thought train correctly then, from my limited perspective on handling microwaves.
The generation side of the circuit requires cyclic refreshing to achieve resonance. {Unknown time-element at the moment}
Once resonance is achieved, {and not before} the energy is dumped into the "Load".
The operational functionality requires simplicity of operation.
The functionality requires the ability to alter running characteristics in realtime.
The length of the initial resonance chamber {ideally} needs to be automatically configurable {hence shawyers use of piezoelectric actuators inside his system}
The mechanical nature of the beam chopper requires simple operation but also an ability to tune in relation to time taken to achieve resonance compared with port-opening cycles. {potentially a software function to find the maximum thrust by adjusting resonance/port operation timing automatically, Microcontrollers are good for this, I use Arduino}
Thinking about the end product it may be easier engineering wise to have multiple attenuation chambers. This allows simplicity in design and beam chopper operation.
2 attenuators at 180, single beam splitter opening with weight adjusted disk to account for mass removed on one side.{less efficient model}
4 attenuation chambers equally spaced so any two are logically 180 degrees from each other, Both can be fed from the resonant chamber simultaneously via 2 opposed holes in the beam splitter. This also allows for slower rotation rate of the splitter as it has 2 holes not 1.
A variable speed rotary port opening mechanism. The shape of the beam choppers pass-through-port determines the efficiency of the opening process, square, circle, ellipse, triangular
For shorter port opening times use 2 disks counter rotating with respect to each other. {or just smaller port openings}.
Personally I tend to favour 4 attenuators because 2 will be simultaneously active while the resonator recharges to pump the other 2 attenuators. {this is also because I have no idea how long it will take to attenuate the signals in relation to achieving resonance}
? any use or.. just junk?
Terrible drawing but you get the basic concept...
...
Regarding the duty cycle, it will depend on the input power, the ability to store energy and the desired thrust. Just keep in mind, if you had the same amplifier setup without the frustum attenuator, it would be more efficient as a microwave photon rocket. I'm afraid this is why I'm not taking the EM drive so seriously anymore. Once I realized I can gain maximum efficiency by just letting the stored energy out as thrust, from a pulsed microwave cavity source of power Q*P, there's not much point in bottling it up in a frustum. The only advantage I see is that it can be used "safely", as opposed to cooking everything down-wind of the exhaust. In space, who cares?
If or when power levels ramp up to "considerable" watts.. we might see unusual things emerge in the environment immediately around the drive.
But then you have that U_0^4 that depends on Q^2 and P^2. As said before, I am not certain that I get a really macroscopic effect even if an interferometric device, sensible enough, can grant observation of the effect. I have to work out some numerics to see really what is going on. There is also the contribution coming from the square of the mode that can take the effect down.
Let's keep working this out.
Hm... from equation (22) I get that a volume integral of the square of the mode times U0/2mu0 is equal to QP/omega. Omega is the resonant angular frequency (which I think is the linear frequency divided by 2pi).
Q is about 10^4 (for the devices we've seen).
Let's say P is about 10^3 (1KW).
omega is about 10^9 (because gigahertz).
mu0 is still about 10^-6.
I don't know about that volume integral, but mu0*QP/omega is about 10^-8. :( Unless the volume integral is a substantially negative power of ten, this isn't helping much. Also, it looks like increasing the resonance frequency actually makes things worse (is that right?!).
U0^4 becomes about 10^-32 divided by the fourth power of that volume integral.
This effect is starting to become too small. :(
Still, these are just back-of-the-envelope ballpark calculations, and I can't figure out all those integrals as my maths isn't good enough. So, as you say, we need proper numerics.
I'm just not too hopeful. :(
I guess the step between Eqn. 55 and Eqn 56 is just to large for me.
Marco loses me at the end there too. Difficult to follow it all the way through, damn index gymnastics makes my eyes glaze over. One thing to note however, equation 3;
alpha*w = sqrt(4pi*eps0*G) has units of Coulombs/kg.
alpha*w*E has units of acceleration, in the sense that this is a Lorentz force q*E/m, divided by mass. Some people believe this is a gravitational acceleration derived from the EM field, but I do not see it as such. It is many orders of magnitude larger than gravity would be. This is essentially the Planck charge / Planck mass
Todd
and let's recall that this apparent acceleration of the photons (of the order of 10^15 m/s^2) in the cavity is invoked by Dr. McCulloch for his theory of Unruh radiation being responsible for the EM Drive's change in momentum http://www.ptep-online.com/index_files/2015/PP-40-15.PDFI guess the step between Eqn. 55 and Eqn 56 is just to large for me.
Marco loses me at the end there too. Difficult to follow it all the way through, damn index gymnastics makes my eyes glaze over. One thing to note however, equation 3;
alpha*w = sqrt(4pi*eps0*G) has units of Coulombs/kg.
alpha*w*E has units of acceleration, in the sense that this is a Lorentz force q*E/m, divided by mass. Some people believe this is a gravitational acceleration derived from the EM field, but I do not see it as such. It is many orders of magnitude larger than gravity would be. This is essentially the Planck charge / Planck mass
Todd
Yes the apparent acceleration (of the photons in the chamber) is of the order of 10^15 m/s^2 in my calculation. very large.
Greetings,Hi and welcome,
I am currently playing catchup (page 151), so my apologies if this has already been talked about. My question is how is the acceleration witness from the emdrive different from the Pioneer anomaly? Full disclosure time; I am not a scientist, but I am a fan of physics. Thank you for the great conversations on this forum.
http://en.m.wikipedia.org/wiki/Pioneer_anomaly
Stumbled on this one:Thanks.
http://arxiv.org/abs/1503.06334 (http://arxiv.org/abs/1503.06334)
I think it can interest @Aero
They say they have conducted an experiment in which microwave photons—relatively low energy packets of light—travelled "instantaneously" between a pair of prisms that had been moved up to 3 ft (1 m) apart. Their experiment involved an optical phenomenon known as "evanescent modes", and they claim that since evanescent modes have an imaginary wave number, they represent a "mathematical analogy" to quantum tunnelling.[32] Nimtz has also claimed that "evanescent modes are not fully describable by the Maxwell equations and quantum mechanics have to be taken into consideration."[48] Other scientists such as Herbert G. Winful and Robert Helling have argued that in fact there is nothing quantum-mechanical about Nimtz's experiments, and that the results can be fully predicted by the equations of classical electromagnetism (Maxwell's equations).[49][50]
Nimtz told New Scientist magazine: "For the time being, this is the only violation of special relativity that I know of." However, other physicists say that this phenomenon does not allow information to be transmitted faster than light. Aephraim Steinberg, a quantum optics expert at the University of Toronto, Canada, uses the analogy of a train traveling from Chicago to New York, but dropping off train cars at each station along the way, so that the center of the ever shrinking main train moves forward at each stop; in this way, the speed of the center of the train exceeds the speed of any of the individual cars.[51]
...Would it be silly to think of a kind of Hawking radiation to "deflate" the frustum?McCulloch's explanation ( http://www.ptep-online.com/index_files/2015/PP-40-15.PDF ) is essentially akin to Hawking radiation, as Unruh radiation is akin to Hawking radiation
As a sanity check, what is the mode shape you predict for the above "resonance" calculation ?
Do you predict resonance at a Transverse Magnetic or Transverse Electric mode ?
what are the predicted mode shape quantum number m,n,p values ?
TMmnp ?
TEmnp ?
Thanks
You need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
...Would it be silly to think of a kind of Hawking radiation to "deflate" the frustum?McCulloch's explanation ( http://www.ptep-online.com/index_files/2015/PP-40-15.PDF ) is essentially akin to Hawking radiation, as Unruh radiation is akin to Hawking radiation
Rodal, thank you for the clarification. I am looking forward to reading more on this wonderful discussion. One quick stupid question: would not the shape of the cavity and the concentration of radiation in the cavity account for the higher acceleration reported? Or am I just way off?The Pioneer anomaly acceleration is towards the Sun, with the radiated heat (T1) occurring away from the Sun, at the back of the Pioneer probe facing the Sun. The temperature (T2) around the EM Drive experiments (+68 F (+20 C)?) is much warmer than the background temperature (T2) at the back of the Pioneer probe (- 292 F (-180 C) around Saturn, for example). The radiative heat transfer goes like the difference of the (absolute) temperatures to the fourth power:
Thank you again.
In other words, I understand that you have developed a spreadsheet model predicting the correct geometry for resonance to occur at, but that you cannot predict whether the resonance occurs in a Transverse Magnetic mode, or a Transverse Electric mode, and that you cannot predict what is the resonance mode shape variation (m. n, p numberrs) in the longitudinal, transverse and azimuthal directions of the truncated cone.As a sanity check, what is the mode shape you predict for the above "resonance" calculation ?
Do you predict resonance at a Transverse Magnetic or Transverse Electric mode ?
what are the predicted mode shape quantum number m,n,p values ?
TMmnp ?
TEmnp ?
Thanks
Roger's bread crumb:QuoteYou need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
Which I followed and used the guide wavelengths, generated from the Df equation, at 1,000 equally spaced diameter points between and including the end plates.
McCulloch's explanation ( http://www.ptep-online.com/index_files/2015/PP-40-15.PDF ) is essentially akin to Hawking radiation, as Unruh radiation is akin to Hawking radiation
Warptech
Just had another look and your right.. jockey shorts.. laughing.
The iris idea is good.
Two counter rotating disks with circular holes could achieve the same thing at higher speed and minimal mechanical effort, better reliability. My experience with sliding mechanical objects has usually not been that good over a reasonable time.... just saying.
I have been thinking about the cavity-resonance element of the em thruster.
I may be totally wrong but I strongly suspect there is far more than just em photons bouncing around inside a tin-can happening. The wave fronts momentum "could"? have a part to play in it but I am pursuing the trail of increased-energy-level confined to a small area, and the non-traditional events that may arise. My conjecture is that the Shawyer em-drive is in a very-mild way (at present power levels) interacting/distorting/impacting/modifying/???? space-time and hence its partner, Gravity, on a local level. If or when power levels ramp up to "considerable" watts.. we might see unusual things emerge in the environment immediately around the drive.
The internal wavefronts inside the drive might somehow be helping to alternately create and then distort the shape and location of a G-modification?.
If the guys at NASA are reading this, are you able to up-the-watts, and test for G-modification not just inside but also around the device??. {please santa}
I dont have any proof to support my conjecture....yet
Please doc this is just a simple question, but why would absolute dimensional numbers be so important as long as you're in the ballpark for resonance? I think every device I've seen has taken into account that either you mechanically tune the EM cavity or shift the insertion frequency to optimize the thrust.In other words, I understand that you have developed a spreadsheet model predicting the correct geometry for resonance to occur at, but that you cannot predict whether the resonance occurs in a Transverse Magnetic mode, or a Transverse Electric mode, and that you cannot predict what is the resonance mode shape variation (m. n, p numberrs) in the longitudinal, transverse and azimuthal directions of the truncated cone.As a sanity check, what is the mode shape you predict for the above "resonance" calculation ?
Do you predict resonance at a Transverse Magnetic or Transverse Electric mode ?
what are the predicted mode shape quantum number m,n,p values ?
TMmnp ?
TEmnp ?
Thanks
Roger's bread crumb:QuoteYou need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
Which I followed and used the guide wavelengths, generated from the Df equation, at 1,000 equally spaced diameter points between and including the end plates.
Therefore we cannot check whether your ("Roger's bread crumb" ?) predicted resonance is correct. :(
I've even thought of using a airtight Conductive Elastic Fabric on the endplate and varying the air pressure the chamber to optimize the reflected EM wave.
...Since whether the EM Drive "thrust" is an experimental artifact or whether it is something that can be used for space propulsion (and if so, what is its theoretical justification) is still unsettled, most issues, like whether it is good enough to be in the ballpark for resonance are very much a subject of debate.
Please doc this is just a simple question, but why would absolute dimensional numbers be so important as long as you're in the ballpark for resonance? I think every device I've seen has taken into account that either you mechanically tune the EM cavity or shift the insertion frequency to optimize the thrust.
I've even thought of using a airtight Conductive Elastic Fabric on the endplate and varying the air pressure the chamber to optimize the reflected EM wave.
Following Roger Shawyers kindly laid bread crumb trail, my EM Drive spreadsheet now can calc the effective internal guide wavelength and external Rf wavelength that will give resonance from end plate to end plate.
As an example for the Flight Thruster big and small end diameters as below, the required end plate to end plate spacing to achieve resonance with an external Rf of 3.85GHz is as below.
Alteration of either the big, small end or Rf frequency will now automatically generate a new Df and from that the end plate spacing needed to achieve resonance with the external Rf.
big diameter m 0.2440000
small diameter m 0.1450000
cavity length m 0.1603484
rf frequency Hz 3,850,000,000
Calculated Df Df 0.49094
slant angle Deg 28.8
1,000 point numerically integrated guide wavelength of the above example is: 0.0801741816
I will publish the spreadsheet but would 1st like to run / verify it against other frustum dimensions and what the calculated / measured resultant resonance was and in what mode.
With this spreadsheet if we know either end diameter, Rf frequency and Df, the other diameter and spacing can now be determined as all 3 dimensions and external Rf wavelength (4 variables) affect each other.
NEXT STEPS:
1) Determine the best way to inject the coax Rf into the Flight Thruster? Loop or Stub?
2) Determine the best location to inject the Rf into the Flight Thruster?
3) Determine the best way to impedance match the Flight Thruster to the impedance of the Rf generator so as to get optimal VSWR and energy delivery to inside the Flight Thruster?
Greetings,
I am currently playing catchup (page 151), so my apologies if this has already been talked about. My question is how is the acceleration witness from the emdrive different from the Pioneer anomaly? Full disclosure time; I am not a scientist, but I am a fan of physics. Thank you for the great conversations on this forum.
http://en.m.wikipedia.org/wiki/Pioneer_anomaly
In other words, I understand that you have developed a spreadsheet model predicting the correct geometry for resonance to occur at, but that you cannot predict whether the resonance occurs in a Transverse Magnetic mode, or a Transverse Electric mode, and that you cannot predict what is the resonance mode shape variation (m. n, p numberrs) in the longitudinal, transverse and azimuthal directions of the truncated cone.As a sanity check, what is the mode shape you predict for the above "resonance" calculation ?
Do you predict resonance at a Transverse Magnetic or Transverse Electric mode ?
what are the predicted mode shape quantum number m,n,p values ?
TMmnp ?
TEmnp ?
Thanks
Roger's bread crumb:QuoteYou need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
Which I followed and used the guide wavelengths, generated from the Df equation, at 1,000 equally spaced diameter points between and including the end plates.
Therefore we cannot check whether your ("Roger's bread crumb" ?) predicted resonance is correct.
...I know I've been reviewing the mode work done by by Frank Davies of NASA and relating it to thrust and I'm observing some interesting correlations between the two. And it's not so much the Q. :-X
Please doc this is just a simple question, but why would absolute dimensional numbers be so important as long as you're in the ballpark for resonance? I think every device I've seen has taken into account that either you mechanically tune the EM cavity or shift the insertion frequency to optimize the thrust.
I've even thought of using a airtight Conductive Elastic Fabric on the endplate and varying the air pressure the chamber to optimize the reflected EM wave.
Since I am skeptical of the derivation of TheTraveller's Shawye's resonance calculation (I am from Missouri: show me :) ) the only way I have to verify it is by comparing the mode shapes to the exact solution (which would also be useful in its own right, as per NASA and Notsosureofit). Since many mode shapes are bunched together at close frequencies, one cannot determine whether a natural frequency prediction is correct unless one assesses the mode shape prediction.
Data, more data!
For instance did you sweep the frequency from ~900mhz to ~3Ghz or just dial in a close TM frequency and then fine tune? If you did sweep do you have any data you could share?
@TheTraveller: Excuse my obtuseness, but don't you have the design freedom to arrange for Df to be as close to unity as you like? If there's one thing that Shawyer's work teaches, it's that maximising Df maximises thrust - therefore this seems to be worthwhile.
So what constraints forbid you designing for near-unity Df?
...Both Frank Davis at NASA (using Finite Element Analysis) and I (using my exact solution) have only performed an eigenvalue analysis problem, from where we obtain the natural frequencies and mode shapes.
For instance did you sweep the frequency from ~900mhz to ~3Ghz or just dial in a close TM frequency and then fine tune? If you did sweep do you have any data you could share?
Dr Rodal did this excellent bit of work, which shows near unity Dfs are possible.I know that - and also I did the same derivations myself (upon which you commented). But that doesn't directly answer my question. You published some specs that showed you are designing to a small Df. Why?
We haven't heard TheTraveller's opinion.
Should we change the Experimental Spreadsheet assuming that Shawyer made a typo and the DesignFactor for the Demonstrator was 0.484 instead of 0.844 ?
...Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!
Thanks a lot. The reason why a material can change the behaviour is magnetic permeability. This can enhance the effect by several magnitude orders. They use low input power, if I am right, and so this could be a good way around to such a limitation.
...Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!
Thanks a lot. The reason why a material can change the behaviour is magnetic permeability. This can enhance the effect by several magnitude orders. They use low input power, if I am right, and so this could be a good way around to such a limitation.
High Density PolyEthylene (HDPE) is a nonconductive polymer with no special magnetic properties, its relative magnetic permeability is very nearly unity, as is generally true of polymers.
Hence we cannot explain the report that NASA observed thrust with a HDPE insert and observed no thrust in a EM device without the HDPE insert based on the relative magnetic permeability of HDPE (which is practically 1).
I think to explain this fact, and still be compatible with Marco's interesting paper, we must use the expression from Maxwell's theory for the speed of light:
1 / c2 = μo εo = (magnetic permeabiltity) * (electric permittivity)
We can use this expression to convert magnetic permeability as follows:
(μo)2 = 1 / ( c4 (εo )2)
if we substitute this expression in the expression for the energy density parameter we obtain:
(Uo)4 / (μo)2 = (Uo)4 c4 εo 2
and therefore we can eliminate the factor of c4 in Eq. 60 and get a more beautiful equation (with one less parameter) that depends explicitly on the electric permittivity as the following quantity gets transformed:
(Pi2 G / ( c4 ) ) Uo)4 / c4 =
(Pi2 G Uo)4 (εo)2
Quote from: TheTravellerDr Rodal did this excellent bit of work, which shows near unity Dfs are possible.I know that - and also I did the same derivations myself (upon which you commented). But that doesn't directly answer my question. You published some specs that showed you are designing to a small Df. Why?
We haven't heard TheTraveller's opinion.
Should we change the Experimental Spreadsheet assuming that Shawyer made a typo and the DesignFactor for the Demonstrator was 0.484 instead of 0.844 ?
Well, I was guessing he'd say yes, so I changed it already on http://emdrive.echothis.com/Experimental_Results. Will of course switch it back if consensus says otherwise.
Could you also put also a (1) next to 0.484 and indicate in the note that Shawyer's reference has 0.844 but that this number gives a small diameter in conflict with the picture of the Demonstrator, therefore it is assumed there was typo transposition of the numbers ?
...
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different...
Iulian is indeed alive and still (one assumes) possesses his eyeballs!
http://www.masinaelectrica.com/emdrive-independent-test/
(1) Magnetic susceptibilities of paramagnetic and diamagnetic materials... see anything interesting?...Reading it I had a question (more than one but..). And this is for everyone, why did Eagle Works observe no thrust in a EM device with no HDPE insert? Makes me wonder what effect achiral materials like this that can induce chirality would have with relativity and electromagnetic fields in your equations?
Thanks nice work!
Thanks a lot. The reason why a material can change the behaviour is magnetic permeability. This can enhance the effect by several magnitude orders. They use low input power, if I am right, and so this could be a good way around to such a limitation.
High Density PolyEthylene (HDPE) is a nonconductive polymer with no special magnetic properties, its relative magnetic permeability is very nearly unity, as is generally true of polymers.
Hence we cannot explain the report that NASA observed thrust with a HDPE insert and observed no thrust in a EM device without the HDPE insert based on the relative magnetic permeability of HDPE (which is practically 1).
I think to explain this fact, and still be compatible with Marco's interesting paper, we must use the expression from Maxwell's theory for the speed of light:
1 / c2 = μo εo = (magnetic permeabiltity) * (electric permittivity)
We can use this expression to convert magnetic permeability as follows:
(μo)2 = 1 / ( c4 (εo )2)
if we substitute this expression in the expression for the energy density parameter we obtain:
(Uo)4 / (μo)2 = (Uo)4 c4 εo 2
and therefore we can eliminate the factor of c4 in Eq. 60 and get a more beautiful equation (with one less parameter) that depends explicitly on the electric permittivity as the following quantity gets transformed:
(Pi2 G / ( c4 ) ) Uo)4 / c4 =
(Pi2 G Uo)4 (εo)2
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different.
We can figure out the true thrust now (T=thrust, a=air effect, in gm-wt)
T + a = -0.54
-T + a = +0.54/7
solving by eliminating ‘a’ gives
T = -0.31 gm-wt
so thrusting forward at the small end
the thrust downwards is around 7 times smaller. difference on the scale is only 0.20 grams
Hi,
When i saw the people start thinking i died i was concerned. I wanted to post when i have some results but now i`m forced me to post some unfinished work :)
I just closed the cone with new setup in place and in the next days i will be busy adjusting the distance and see if i have any improvement. The work will be slow because i need to make a lot of tests with different distance for each test i need to let the magnetron to cool down for at least 5 minutes.
Iulian
...
(1) Magnetic susceptibilities of paramagnetic and diamagnetic materials... see anything interesting?
http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_6.html
We are both wrong. He said two contradictory thingsWe can figure out the true thrust now (T=thrust, a=air effect, in gm-wt)
T + a = -0.54
-T + a = +0.54/7
solving by eliminating ‘a’ gives
T = -0.31 gm-wt
so thrusting forward at the small endQuotethe thrust downwards is around 7 times smaller. difference on the scale is only 0.20 grams
I'm confused.
From Iulian's quote, wouldn't Test 1 = 0.2*7=1.4g and Test 2 = 0.2 . Then the equation would be set up like this?
T=thrust
A=air
T+A=1.4g
T-A=0.2g
T=0.8g
A=0.6g
We haven't heard TheTraveller's opinion.
Should we change the Experimental Spreadsheet assuming that Shawyer made a typo and the DesignFactor for the Demonstrator was 0.484 instead of 0.844 ?
Well, I was guessing he'd say yes, so I changed it already on http://emdrive.echothis.com/Experimental_Results. Will of course switch it back if consensus says otherwise.
I also think the cavity length needs to be adjusted on the Demonstrator Thruster to .187m.
My reasoning and measurements:
I believe Shawyer angled the cone to his expectation of where the small diameter plate will be. When the device is turned on the plate is slightly back inside the cylinder and gradually moved forward until there is phase lock. The length of the cylinder, in part, is to accommodate the movement mechanism and the volume of the small plate.
In my recent model the cone length is exactly .187m (from the face of the small plate to the face of the large plate). Slightly longer than the .183m calculated from 3 * .123m / 2 - based on .2450Ghz. I think 4mm is ample distance to move the small plate to achieve phase lock as I described above.
Did I do the math right?
...
(1) Magnetic susceptibilities of paramagnetic and diamagnetic materials... see anything interesting?
http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_6.html
mass susceptibility per kilogram, χ, at 20°C
Vacuum . . . . 0
Polyethylene . . .+0.2 *10^(-8) (paramagnetic)
Aluminium . . . . +0.82*10^(-8) (paramagnetic)
Copper . . . . −0.107*10^(-8) (diamagnetic)
All very small values compared to iron, cast iron and other magnetic materials
The value for Polyethylene confirms that the magnetic permeability of HDPE shoud be close to 1.
However, this is for the real part of the susceptibility. I recall that Paul March said that what was most interesting were the imaginary components of the permittivity and the permeability.
Can anyone find the imaginary permittivity and imaginary permeability for HDPE ?
The imaginary parts act as absorption coefficients (more in the direction of attenuation pointed out by Todd)
...Chris's article mentioned some very fast transit times, but no mention of what the actual impulse number is.Welcome to the thread. Just a short answer and comment regarding the above points. It was not Chris's article. I was one of three authors. The sections you describe paraphrased exactly what Dr. White had written in AIAA papers and what Paul March had written in his papers or at the forum. There was not enough space to provide a thorough review of the theories in a form that could be understood to a general audience. I did add to the article a number of objective counterarguments where appropriate as the fact that the EM Drive appears to violate conservation of momentum. In General Relativity momentum and energy are tied together in the stress-energy tensor, so that if something violates conservation of momentum it is not surprise that it will violate conservation of energy.
...Chris's article didn't seem to indicated that the power requirements were unfeasible. And that the thrust to power input ratio went down as power went up? ...
We are both wrong. He said two contradictory thingsWe can figure out the true thrust now (T=thrust, a=air effect, in gm-wt)
T + a = -0.54
-T + a = +0.54/7
solving by eliminating ‘a’ gives
T = -0.31 gm-wt
so thrusting forward at the small endQuotethe thrust downwards is around 7 times smaller. difference on the scale is only 0.20 grams
I'm confused.
From Iulian's quote, wouldn't Test 1 = 0.2*7=1.4g and Test 2 = 0.2 . Then the equation would be set up like this?
T=thrust
A=air
T+A=1.4g
T-A=0.2g
T=0.8g
A=0.6g
"I got 1/7th of the previous thrust, in the opposite direction" and
"I got 2 gm-wt thrust downwards"
Originally he got 0.54 gm-wt upwards, so 1/7th would be 0.08 - yet he says 0.2
I'll go with 0.2. T assumed towards small end.
T + A = 0.54 (up)
-T + A = -0.2 (down)
Solving:
T = 0.37 (thrusts from small end)
A = 0.17 (~50% of the thrust)
...
The use of HDPE rather than PTFE at MW freqs has been bothering me. Nowhere over 1 GHz have I heard of HDPE, which could indicate high moisture absorption or reflectability. Also, the melting point of HDPE is rather low compared to the 250 deg C of PTFE.
The comparison tables are here: http://www.vanderveerplastics.com/compare-materials.html?sel1=hdpe&sel2=teflon-ptfe-fep
If someone knows why HDPE (typically plastic milk jugs( were initially used, it would be interesting.
"High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. It is sometimes called "alkathene" or "polythene" when used for pipes.[1] With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code (formerly known as recycling symbol)." per http://en.wikipedia.org/wiki/High-density_polyethylene
The bottom line is that nobody understands how this thing works.
I just uploaded the video with the upside down test. in the next days i will start testing the new setup with the adjustable length.Great! You got a thrust reversal.
https://www.youtube.com/watch?v=KAMttfMC8PI
Take a gander at the section on energy conservation here:
http://emdrive.echothis.com/Generic_EM_Drive_Information
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
Just think about it, even at the lower frequency used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212
and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric
Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.
With the possible exception of Prof. Yang in China.
Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.
All tests move towards the small end, including these new tests. I don't think anyone was shown movement toward the large end... ???
With the possible exception of Prof. Yang in China.
Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.
All tests move towards the small end, including these new tests. I don't think anyone was shown movement toward the large end... ???
I may not recall this correctly since I have not read those papers in a long time. Can somebody point out to an explicit reference showing actual measurements (not the computer simulations by Yang) of which way did Yang's device move ?
Notice that in this chart (by Shawyer), Prof. Yang's thruster and Shawyer's Flight Thruster are shown with measurements in the opposite direction:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776944;image)
I just uploaded the video with the upside down test. in the next days i will start testing the new setup with the adjustable length.
https://www.youtube.com/watch?v=KAMttfMC8PI (https://www.youtube.com/watch?v=KAMttfMC8PI)
...
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different...
Some information from NASA on their experiments with the truncated cone with the HDPE insert:
............................................
Take a gander at the section on energy conservation here:
http://emdrive.echothis.com/Generic_EM_Drive_Information
Just thinking that maybe there should be a third option: Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ? This would be what, a "false force" driven by the dispersion cycle in the cavity ?? I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.
That's correct. The Brady et.al. report does not mention the dielectric material used in the truncated cone measurements....
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different...
Some information from NASA on their experiments with the truncated cone with the HDPE insert:
............................................
Forgive me if this has been answered already, but when did they change the dielectric to HDPE?
The Anomalous thrust paper clearly states that a PTFE slug was used in the Cannae drive and there is no mention of HDPE in the paper.
The attached table shows a column labeled "force direction" which shows, for Prof. Yang's device and for the Flight thruster to have opposite force direction to all the measurements at NASA Eagleworks.With the possible exception of Prof. Yang in China.
Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.
All tests move towards the small end, including these new tests. I don't think anyone was shown movement toward the large end... ???
I may not recall this correctly since I have not read those papers in a long time. Can somebody point out to an explicit reference showing actual measurements (not the computer simulations by Yang) of which way did Yang's device move ?
Notice that in this chart (by Shawyer), Prof. Yang's thruster and Shawyer's Flight Thruster are shown with measurements in the opposite direction:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776944;image)
Shawyers Thrust is the direction of the internal force imbalance. As a result of that internal force imbalance, the device moves in the Reaction direction.
This is explained in most of his papers.
Shawyers Thrust is the direction of the internal force imbalance. As a result of that internal force imbalance, the device moves in the Reaction direction.
This is explained in most of his papers.
Thus the radiation pressure at the larger end plate is higher than that at the smaller end plate. The resulting force difference (F_g1 - F_g2) is multiplied by the Q of the resonant assembly.
Now λ_g2 > λ_g1, due to the difference in cross-section, and hence F_g1 > F_g2. Therefore the resultant thrust T will be T = F_g1 - F_g2 = 2P_0/c (λ_0/λ_g1 - λ_0/λ_g2).
Thus as the velocity of the waveguide increases in the direction of thrust, the thrust will decrease until a limiting velocity is reached when T = 0.
No. You are muddling everything up.I don't know who are you addressing as "muddling everything up", but Shawyer's chart shows for NASA's experiments with the frustum of a cone, with a dielectric:
The diagrams show "thrust" to be BIG END FORWARD.
The diagrams show "reaction" to be SMALL END FORWARD.
I recommend you use that nomenclature. It's unambiguous.
Force direction: thrust
which according to you, "thrust" means in the direction of the BIG END FORWARD
which therefore means force direction towards BIG END
and that's wrong. The force measured at NASA was towards the small end, that's one thing we know for a fact, no matter what Shawyer may write about NASA's experiments.
We have discussed the issue of force measurement and displacement measurement at NASA at length with Paul March in these threads.
Traveller, can you recommend another of Shawyer's papers to read where I can find this argument?
~Kirk
Sorry but your nomenclature for me is as ambiguous as all get out
Welcome to the thread. Just a short answer and comment regarding the above points. It was not Chris's article. I was one of three authors.
I don't know who are you addressing as "muddling everything up", but Shawyer's chart shows for NASA's experiments with the frustum of a cone, with a dielectric:
Force direction: thrust
which according to you, "thrust" means in the direction of the BIG END FORWARD
which therefore means force direction towards BIG END
and that's wrong. The force measured at NASA was towards the small end, that's one thing we know for a fact, no matter what Shawyer may write about NASA's experiments.
We have discussed the issue of force measurement and displacement measurement at NASA at length with Paul March in these threads.
Take a gander at the section on energy conservation here:
http://emdrive.echothis.com/Generic_EM_Drive_Information
Just thinking that maybe there should be a third option: Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ? This would be what, a "false force" driven by the dispersion cycle in the cavity ?? I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.
I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.
The bottom line is that nobody understands how this thing works.
I've seen reference to the Demonstrator Thrusters DF as .844 in 3 different Shawyer documents now. Hmmmm something seems amissCan you please provide the links (or attach pdf) to all 3 references havign DF = 0.844 ?
Thank you, from one old dog to another. Like I've told others I remember when engineering/science was a rock hitting a rock, then it all turned to dirt. That short answer is long on my understanding.
Take a gander at the section on energy conservation here:
http://emdrive.echothis.com/Generic_EM_Drive_Information
Just thinking that maybe there should be a third option: Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ? This would be what, a "false force" driven by the dispersion cycle in the cavity ?? I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.
I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.
The short answer is yes. As RODAL mentioned above, putting a pair of frequencies at the half-power points of the resonance. I did my thesis on cylindrical cavity resonance that way, many long years ago.
...
The use of HDPE rather than PTFE at MW freqs has been bothering me. Nowhere over 1 GHz have I heard of HDPE, which could indicate high moisture absorption or reflectability. Also, the melting point of HDPE is rather low compared to the 250 deg C of PTFE.
The comparison tables are here: http://www.vanderveerplastics.com/compare-materials.html?sel1=hdpe&sel2=teflon-ptfe-fep
If someone knows why HDPE (typically plastic milk jugs( were initially used, it would be interesting.
"High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. It is sometimes called "alkathene" or "polythene" when used for pipes.[1] With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code (formerly known as recycling symbol)." per http://en.wikipedia.org/wiki/High-density_polyethylene
HDPE has very interesting properties, it has been used for biomedical applications, for garbage bags and countless commercial applications. It is very tough, it has excellent sliding abrasion resistance and is self lubricating.
As to why it was used as a dielectric for NASA's EM Drive, my recollection is that it was based on prior experience by Paul March, originally working with Prof. Woodward on his Mach Effect theory and experiments, and that it was based, as I noted above, on the imaginary properties acting as absorption coefficients in electromagnetic waves.
By the way, NASA also used PTFE and Nitrile Rubber as dielectrics. They obtained the highest thrust force with HDPE
IULIAN:That's all true, and hanging one's hat on the value of the thrust and the air mass change is not to be recommended yet. I shouldn't have quoted them to three significant figures because the experimental precision is in no way that good. I also noticed how much the readings were changing during this very latest test.Hi,
.......snip
Iulian
Another thing to consider; From your video you have the unit on the end of a looped spring hanging from a shelf.... For the Downwards test you are trying to force the unit downwards AGAINST the natural TENSION of the spring... you need to measure just how much energy it takes to pull the spring down as much as the unit did when you powered it up.!
The original "thrust was with the aid of the spring pulling the unit upwards.
Placing the complete unit onto a balance board "like a child's see-saw, American teeter-totter" with an equal weight on the other end will enable you to perform these types of measurements
...HDPE has an unusual Dielectric Constant (K or E) variance of 1 to 5 while PTFE has confined K of 2-2.1. This is probably why HDPE is not normally used in MW circuits...unpredictability or randomness, if you will. In essence, a puck/layer of HDPE would present a wide K variance across its surface to EM, unlike PTFE. Few materials have this: http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm
...
Thanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).
I've seen reference to the Demonstrator Thrusters DF as .844 in 3 different Shawyer documents now. Hmmmm something seems amissCan you please provide the links (or attach pdf) to all 3 references havign DF = 0.844 ?
Thank you, from one old dog to another. Like I've told others I remember when engineering/science was a rock hitting a rock, then it all turned to dirt. That short answer is long on my understanding.
Take a gander at the section on energy conservation here:
http://emdrive.echothis.com/Generic_EM_Drive_Information
Just thinking that maybe there should be a third option: Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ? This would be what, a "false force" driven by the dispersion cycle in the cavity ?? I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.
I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.
The short answer is yes. As RODAL mentioned above, putting a pair of frequencies at the half-power points of the resonance. I did my thesis on cylindrical cavity resonance that way, many long years ago.
I've seen reference to the Demonstrator Thrusters DF as .844 in 3 different Shawyer documents now. Hmmmm something seems amissCan you please provide the links (or attach pdf) to all 3 references havign DF = 0.844 ?
These are basically all the "same" paper. Copy and Paste.
"Mimics G".. I like that phrase, a lot.
... nice!!.
I would be cautious of closing the door on em-density. Instinct still has me thinking possibly more of an E relationship than B:H, but a rig to test it implies considerable values of E. Somewhere lurking in here I think polarisation is also a factor.
Well dang, here I thought we had nailed down the mystery acceleration. Alas, we still have this systemic anomaly ( I love that phrase). All along I thought we could point our fingers at the chirality of twisted polymer crystals. http://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4...HDPE has an unusual Dielectric Constant (K or E) variance of 1 to 5 while PTFE has confined K of 2-2.1. This is probably why HDPE is not normally used in MW circuits...unpredictability or randomness, if you will. In essence, a puck/layer of HDPE would present a wide K variance across its surface to EM, unlike PTFE. Few materials have this: http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm
...
HDPE is not random. It is fairly straightforward to characterize as having well determined properties, based on its molecular weight for example, and method of manufacture. If the properties of HDPE would be random or difficult to characterize, believe me that HDPE would not be used for biomedical applications, which have higher standards for material properties than many commercial applications do.
What happened here is that you are looking at this row:
High Density Polyethylene (HDPE), Molded 1.0 - 5.0
instead of looking at this one, which is the appropriate row to look at:
Polyethylene LDPE/HDPE 2.26 @ 1 MHz
2.26 @ 3 GHz
Those are the appropriate properties for the NASA Eagleworks dielectric.
Now: that's a narrow range, and it even gives you data at the GHz range for direct application to microwaves.
NASA Eagleworks did not use a molded product (see my previous posts, given the identity of the product used by NASA).
Having said that, the fact that this website gives properties for HDPE in two completely different rows, with different ranges, and does not explain the differences does not give me a good impression about the quality of the data in this website (which is also the same website I initially found when I was quickly looking for the HDPE properties)
Authoritative handbooks like this one give much more reliable data than these websites: http://bit.ly/1Lr0pSt
Of course, the best thing is to have analytical instruments to properly characterize the material properties of a polymer, which is what we did.
Note that in this same website they also have this funny note, acknowledging that they had the tan delta for PTFE off by a factor of 10 until Craig ;) found the error !!!!!QuoteThanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).
I have a couple of 6L6s in the old radio I just rebuilt, because it's just like the one I rebuilt when I was 14. Hats off to you.
Old??? I was looking at ion drives and wondering why we don't use beam focusing plates like a 6L6. :)
But I am wondering something. If this thing works on standing waves, and standing waves require a node on both ends of the cavity, wouldn't this thing have a cylinder of standing waves surrounded by traveling waves?
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
Even at the lower frequency (almost 1/2 of the Flight Thruster) used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212
and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric
Do we have the Flight Thruster Dimensions? I have found bD: .265 m height: .164mBased on the photograph, and knowing that bD: .265m; height: .164m; what is your estimate of the small diameter ?
...
"Mimics G".. I like that phrase, a lot.
... nice!!...
I think that if there were a charged particle oscillating from end to end inside, it would be more obvious than when it's photons. The charge feels the force of it's oppositely charged reflection in the copper ground plane, and wants to drag it along with it. It would be an interesting problem to calculate the electric field of a point charge, inside a frustum and see what the forces on that test particle would be. ::)
Todd
I have a couple of 6L6s in the old radio I just rebuilt, because it's just like the one I rebuilt when I was 14. Hats off to you.
Old??? I was looking at ion drives and wondering why we don't use beam focusing plates like a 6L6. :)
But I am wondering something. If this thing works on standing waves, and standing waves require a node on both ends of the cavity, wouldn't this thing have a cylinder of standing waves surrounded by traveling waves?
I still have an old T-shirt from the 60's that had the year 2000 on the top and a group of flying cars displayed below. We're a few years behind in having flying cars that levitate and spacecraft that zoom around, but I'd sure love to see it happen before...you know. I think we're close, very close to that childhood dream. (sorry if I got off track but we're all dreamers here)
As far as your question of a cavity of standing waves surrounded by standing waves you might have a look at these different modes.
Lately. I see a lot of new criticism. I think its fine, but I also think that there were a lot of tests that have proven that there is a thrust.
I am writting this to share this idea. Is it possible to convince some of the main critics of this device to manufacture their own EmDrive and test it? I think that their criticism can not be taken seriously and scientificaly correct, if they do not make their own tests. I say yes to criticism, but I can not take it seriously until they make their own tests.
...
Chrochne
Do we have the Flight Thruster Dimensions? I have found bD: .265 m height: .164mBased on the photograph, and knowing that bD: .265m; height: .164m; what is your estimate of the small diameter ?
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
Even at the lower frequency (almost 1/2 of the Flight Thruster) used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212
and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric
The TM01 mode is the mode shown to have the highest reflection, per Zeng and Fan's paper.
https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583
It also has fairly high attenuation. To raise Q, Shawyer needed more reflection, so he made the cone angle greater, which may or may not be counter productive at the lower attenuation value depending on how high a Q he can get. You can see why in the attachments.
Do we have the Flight Thruster Dimensions?
I have found
bD: .265m
height: .164m
freq: 3.85GHz
DF: ?
sD: ?
IULIAN:Hi,
.......snip
Iulian
Another thing to consider; From your video you have the unit on the end of a looped spring hanging from a shelf.... For the Downwards test you are trying to force the unit downwards AGAINST the natural TENSION of the spring... you need to measure just how much energy it takes to pull the spring down as much as the unit did when you powered it up.!
The original "thrust was with the aid of the spring pulling the unit upwards.
Placing the complete unit onto a balance board "like a child's see-saw, American teeter-totter" with an equal weight on the other end will enable you to perform these types of measurements
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
Even at the lower frequency (almost 1/2 of the Flight Thruster) used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212
and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric
The TM01 mode is the mode shown to have the highest reflection, per Zeng and Fan's paper.
https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583
It also has fairly high attenuation. To raise Q, Shawyer needed more reflection, so he made the cone angle greater, which may or may not be counter productive at the lower attenuation value depending on how high a Q he can get. You can see why in the attachments.
When i saw the people start thinking i died i was concerned. I wanted to post when i have some results but now i`m forced me to post some unfinished work :)
We also really need FAQ a lot :-P. Too much folks are asking about the questions that were already answered and properly tested before.
As I'll never have time to read through the previous 200+ pages ...
This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.
Backs up the Patent mention of TM01 mode.
Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=831551;image)
Well dang, here I thought we had nailed down the mystery acceleration. Alas, we still have this systemic anomaly ( I love that phrase). All along I thought we could point our fingers at the chirality of twisted polymer crystals. http://www.esrf.eu/UsersAndScience/Publications/Highlights/2011/scm/scm4...HDPE has an unusual Dielectric Constant (K or E) variance of 1 to 5 while PTFE has confined K of 2-2.1. This is probably why HDPE is not normally used in MW circuits...unpredictability or randomness, if you will. In essence, a puck/layer of HDPE would present a wide K variance across its surface to EM, unlike PTFE. Few materials have this: http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm
...
HDPE is not random. It is fairly straightforward to characterize as having well determined properties, based on its molecular weight for example, and method of manufacture. If the properties of HDPE would be random or difficult to characterize, believe me that HDPE would not be used for biomedical applications, which have higher standards for material properties than many commercial applications do.
What happened here is that you are looking at this row:
High Density Polyethylene (HDPE), Molded 1.0 - 5.0
instead of looking at this one, which is the appropriate row to look at:
Polyethylene LDPE/HDPE 2.26 @ 1 MHz
2.26 @ 3 GHz
Those are the appropriate properties for the NASA Eagleworks dielectric.
Now: that's a narrow range, and it even gives you data at the GHz range for direct application to microwaves.
NASA Eagleworks did not use a molded product (see my previous posts, given the identity of the product used by NASA).
Having said that, the fact that this website gives properties for HDPE in two completely different rows, with different ranges, and does not explain the differences does not give me a good impression about the quality of the data in this website (which is also the same website I initially found when I was quickly looking for the HDPE properties)
Authoritative handbooks like this one give much more reliable data than these websites: http://bit.ly/1Lr0pSt
Of course, the best thing is to have analytical instruments to properly characterize the material properties of a polymer, which is what we did.
Note that in this same website they also have this funny note, acknowledging that they had the tan delta for PTFE off by a factor of 10 until Craig ;) found the error !!!!!QuoteThanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).
Perhaps counterintuitively, these imaginary components are dissipative. Which is A Bad Thing. Probably :)...Base question is: Why does HDPE preform better than PTFE in high EM field experiments? (HDPE does have roughly half the thermal resistance of PTFE)....Paul March's answer is that it has to do with the imaginary components of the electric permittivity and magnetic permeability, and the choice was based on his experience working with Prof. Woodward.
I haven't found values for the imaginary components of the electric permittivity and magnetic permeability of HDPE in the literature.
To assess this issue we need actual experimental values of the imaginary components of the electric permittivity and magnetic permeability of HDPE.
...perhaps counterintuitively, these imaginary components are dissipative. Which is A Bad Thing. Probably :)Of course they are dissipative, but it is straightforward to show that the time-average value of the Poynting vector, which is zero for a non-dissipative homogeneous cavity becomes non-zero for an asymmetric cavity with a dielectric with dissipative properties (one can show this even just based on the electric Tan Delta, as I did in the thread many pages ago).
I also think the cavity length needs to be adjusted on the Demonstrator Thruster to .187m....
0.187 m is the minimum axial length. The Demonstrator has a gear-driven mechanism at the small end in order to change the internal length to tune the cavity.
Could you please figure out -from the picture- the maximum length for the Demonstrator so that we can put both these values (minimum length and maximum length) in the wiki (http://emdrive.echothis.com/Experimental_Results) for EM Drive ?
Either use the thickness of the interior plate and gears equal to zero, or use your best guesstimate.
Haven't seen anyone post this to the thread so far.
https://hackaday.io/project/5596-em-drive
Plus interview with the team leader.
http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive
Haven't seen anyone post this to the thread so far.Excellent set of strategies these guys are using. In parallel they're doing a Shawyer/Chinese replication attempt @2.4 GHz, and also building a 25 GHz beast with the aim of popping it into a PocketQub and sending it into space (which one of them has already done with a different project).
https://hackaday.io/project/5596-em-drive
Plus interview with the team leader.
http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive
Traveller, can you recommend another of Shawyer's papers to read where I can find this argument?
Page 4 [of the Toulouse 2010 paper (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=831580)] explains it.
The resulting design must also ensure a low taper slope, to minimise the axial component of side wall forces.
It is clear that if the minimum dimension was the cut off diameter, force F_g2 would be zero. However because there would still be a significant small end plate area, the projected area of the side wall would not equal the area of the large end plate. Thus any attempt to show a resultant zero net force due to equalisation of areas is incorrect.
Note that to maintain the principle of the conservation of momentum, the acceleration of the waveguide due to thrust, is opposite to the actual thrust direction. Thus, in Fig 3, the sign convention for the waveguide velocity axis is:
<----- ----->
Acceleration Vector Thrust Vector
When the waveguide is accelerated along the acceleration vector, the thrust approaches a maximum of 1. However, as the velocity of the waveguide increases in the direction of thrust, the thrust will decrease to zero.
...Base question is: Why does HDPE preform better than PTFE in high EM field experiments? (HDPE does have roughly half the thermal resistance of PTFE)....Paul March's answer is that it has to do with the imaginary components of the electric permittivity and magnetic permeability, and the choice was based on his experience working with Prof. Woodward.
Another "bread crumb": concerning "Patent mention of TM01 mode", there are an infinite number of TM modes having m=0, n=1, and p=1,2,3...Infinity. None of them (for a truncated cone) have p = 0
You need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
Looking at the difference in melting points between HDPE and PTFE, the "improved" performance might be due to out gassing from HDPE as it is over heated.No reported internal temperatures for NASA Eagleworks.
What is the temperature inside the device during a test run?
Looking at the difference in melting points between HDPE and PTFE, the "improved" performance might be due to out gassing from HDPE as it is over heated.No reported internal temperatures for NASA Eagleworks.
What is the temperature inside the device during a test run?
Externally, the hottest face was the big diameter covered with fiber-reinforced epoxy facing the outside, hence external outgassing of the epoxy is probably just as or more likely to produce thrust than internal outgassing of HDPE (more free volume in fiber-reinforced epoxy than in HDPE and the epoxy is on the outside)
...
It's Michelle, friends call me Shell. Yes, I love mixing and matching different fields. In the real world of building things that need to be used (my company and I built semiconductor equipment) they need to incorporate virtually all the arts and while you might not have a Phd in a subject you better know enough when someone on your design team is full of hockey poo and they are 3 and 2 at the plate (US Baseball term, 3 balls and 2 strikes).
I'm reading a couple papers that are taking me into an idea of why we're seeing something unexpected in these slugs of material inserted in the cavity. Not sure if the two will dovetail into something useful or not or I'm 3 and 2 at the plate.
Thanks for the heavy reading links I'll digest it all and post later.
Thank you for your insight and your help
...HDPE is super cheap and readily available. Its that white cutting board material you find in many stores, like this: http://www.ebay.com/itm/6-x-8-x-1-2-Thick-White-Plastic-HDPE-Cutting-Board-FDA-NSF-USDA-/281539165633 Doc said it was used in medical field as well; easy to sterilize and resistant to abrasion.
The advantage that HDPE is a linear polymer with very few branches is very important. This is because when advanced polymer processing technology such as hydrostatic extrusion is used, polyethylene chains will be aligned in the extrusion direction and hence high modulus and high strength materials can be produced.
The high density polyethylene discs dielectric's relative permittivity is 2.27 at 2.0 GHz with a dissipation factor of ~0.0005.So that is what Eagleworks used.
Another "bread crumb": concerning "Patent mention of TM01 mode", there are an infinite number of TM modes having m=0, n=1, and p=1,2,3...Infinity. None of them (for a truncated cone) have p = 0
After doing some more reading, it seems clear that Shawyer is only interested in resonance between the end plates at the frustum's effective electrical length, which depends on the integral of the constantly changing guide wavelength from one end plate to the other. Operational Rf wavelength is then some multiple of that effective wavelength. For non adjustable Rf generators, having the ability to vary the frustum length will allow operation at resonance. Here we need to fully understand, the physical end plate separation will not have a subharmonic relationship with the Rf generators wavelength.
Shawyers method to calc the frustum's effective electrical length:QuoteYou need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
As I want to operate in TM01 mode, as stated in Shawyer's patent and several of his publications, the big and small end cutoff wavelengths and the associated guide wavelengths (as in the quote) are different to TE mode. This recommended method which only focuses on length resonance, as mentioned in many of the Shawyer publications, seems to be different to what NASA and other have done, are doing.
What this means is Shawyer is treating his frustum as a resonate cylinder that has variable guide wavelengths from one end to the other. His only interest in the radius or diameter is how it effects the guide wavelength and what the integral of all the constantly changing guide wavelength over the length of the cylinder is.
Paul answered a question for me back in mid April.QuoteThe high density polyethylene discs dielectric's relative permittivity is 2.27 at 2.0 GHz with a dissipation factor of ~0.0005.So that is what Eagleworks used.
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
My exact solution for Magnetic Field cylTM212
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.
Does anybody have any other info as to Shawyer excites his Flight Thruster?
Not what NASA or I predict ? ???
what prediction are you referring to ? ???
You need to develop a numerical model that calculates the guide wavelength, for the chosen mode, at discrete small increments along the cavity length and then integrate them into an effective wavelength for the whole cavity.
All SPR cavities were designed using our in-house software which can cover a range of geometries and modes.
Hi Traveller
I have no problems with you disclosing all your work, the more working EmDrives there are in the world the better.
However I would be grateful if you could emphasise the dangers of working with high power, high Q, microwave devices before someone gets seriously injured.
Thanks
Best regards
Roger
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.
Does anybody have any other info as to Shawyer excites his Flight Thruster?
Dude. DUDE. The resonance modes for a spherical tapered cavity are solved, analytically. They are exact solutions. There is no doubt to any of them. Many simple cavity shapes have been solved for decades, and all experimental data backs these solutions very well. This is what Rodal is trying to tell you.
You cannot have a TM01 mode in any cavity. This is a waveguide mode. It is like saying 'I'm going to drive down the road at 100kph in my car, in the garage with the garage door closed'. It makes no sense. You can play semantic games and say it applies to infinitely long cavities, but that's just a waveguide.
The way you ignore salient posts with basic enclosed scientific facts makes you look like a VX Junky, and people won't take you very seriously after a while.
Haven't seen anyone post this to the thread so far.Excellent set of strategies these guys are using. In parallel they're doing a Shawyer/Chinese replication attempt @2.4 GHz, and also building a 25 GHz beast with the aim of popping it into a PocketQub and sending it into space (which one of them has already done with a different project).
https://hackaday.io/project/5596-em-drive
Plus interview with the team leader.
http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.
Does anybody have any other info as to Shawyer excites his Flight Thruster?
Dude. DUDE. The resonance modes for a spherical tapered cavity are solved, analytically. They are exact solutions. There is no doubt to any of them. Many simple cavity shapes have been solved for decades, and all experimental data backs these solutions very well. This is what Rodal is trying to tell you.
You cannot have a TM01 mode in any cavity. This is a waveguide mode. It is like saying 'I'm going to drive down the road at 100kph in my car, in the garage with the garage door closed'. It makes no sense. You can play semantic games and say it applies to infinitely long cavities, but that's just a waveguide.
The way you ignore salient posts with basic enclosed scientific facts makes you look like a VX Junky, and people won't take you very seriously after a while.
I'm just the messenger telling folks here what I have read many times and what Roger Shawyer has shared with me.
Ignore him if you will but his and the Chinese EM Drives are working based on his knowledge.
BTW he treats the Em Drive conic frustum as a infinite series of open circular waveguides, each with a different diameter, that cause the guide wavelength and group velocity to vary as per that diameter. Have you read what he says?
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.
Does anybody have any other info as to Shawyer excites his Flight Thruster?
Dude. DUDE. The resonance modes for a spherical tapered cavity are solved, analytically. They are exact solutions. There is no doubt to any of them. Many simple cavity shapes have been solved for decades, and all experimental data backs these solutions very well. This is what Rodal is trying to tell you.
You cannot have a TM01 mode in any cavity. This is a waveguide mode. It is like saying 'I'm going to drive down the road at 100kph in my car, in the garage with the garage door closed'. It makes no sense. You can play semantic games and say it applies to infinitely long cavities, but that's just a waveguide.
The way you ignore salient posts with basic enclosed scientific facts makes you look like a VX Junky, and people won't take you very seriously after a while.
I'm just the messenger telling folks here what I have read many times and what Roger Shawyer has shared with me.
Ignore him if you will but his and the Chinese EM Drives are working based on his knowledge.
BTW he treats the Em Drive conic frustum as a infinite series of open circular waveguides, each with a different diameter, that cause the guide wavelength and group velocity to vary as per that diameter. Have you read what he says?
Please answer me this: Have you read any derivation of the exact solution for ANY cavity? (or waveguide?)
Precisely what "exact solution numbers generated by" me are not being matched ?Quote from: rfcavityPlease answer me this: Have you read any derivation of the exact solution for ANY cavity? (or waveguide?)
I contacted Shawyer & asked him how to calc end plate separation to obtain resonance at the desired external Rf. He provided the information / solution I have shared, which does not match exact solution numbers generated by Dr. Rodal for the same conic frustum dimensions...
Precisely what "exact solution numbers generated by" me are not being matched ?Quote from: rfcavityPlease answer me this: Have you read any derivation of the exact solution for ANY cavity? (or waveguide?)
I contacted Shawyer & asked him how to calc end plate separation to obtain resonance at the desired external Rf. He provided the information / solution I have shared, which does not match exact solution numbers generated by Dr. Rodal for the same conic frustum dimensions...
The TM212 solution that was verified with the thermal imaging ?
Does Shawyer have a method of solution that shows that COMSOL's Finite Element analysis program is wrong ?
Does Shawyer have a different thermal image of the NASA fustrum ? and the thermal image camera from NASA is defective ?
Shawyer & Chinese conic frustums provide thrust that matches their equations predictions.Please cite an example set of numbers that instantiates this:
???
Starting to wonder if I'm reading an updated version of Hansel and Gretel.... with all those bread crumb references ?
Seriously TheTraveler, I'd rather see you start building your setup instead of getting entangled in endless debates about R.Shawyer's merits.
With your insights and eye for detail, I'm sure your test will be much more informative then the crude (but very interesting/promising) test Iullian made.
So please man, stop digging trenches and go for what you originally planned to do : build a working model...
All this ping-pong stuff about what or what not Shawyer said/did/might have said/ could have meant...sigh... you should not take the criticism on Shawyer's texts as personal "insult"(maybe a big word).... it is all a distraction...let it go...and focus again...
You started so well... :-\
Haven't seen anyone post this to the thread so far.Excellent set of strategies these guys are using. In parallel they're doing a Shawyer/Chinese replication attempt @2.4 GHz, and also building a 25 GHz beast with the aim of popping it into a PocketQub and sending it into space (which one of them has already done with a different project).
https://hackaday.io/project/5596-em-drive
Plus interview with the team leader.
http://n-o-d-e.net/post/119343131451/building-a-diy-emdrive
There might be an even cheaper way of testing an EmDrive in weightlessness than a small space probe: A drop tower like the Fallturm in Bremen, Germany:
http://en.wikipedia.org/wiki/Fallturm_Bremen
At that particular facility you can get up to 9 seconds of weightlessness and the capsule for your experiment can be a lot bigger than a PocketQub for example. It can be up to 0.8m in diameter and up to 2.4m in length. The vacuum inside the structure during the experiment is probably not of a high quality but nothing is stopping you from having an even better vacuum inside your capsule. Using a drop tower would allow for multiple tests with the same hardware with modifocations in between the shots if needed.
I just wanted to put this idea out there.
United States
Peter Diamandis of Zero Gravity Corporation
In late 2004, the Zero Gravity Corporation became the first company in the United States to offer zero-g flights to the general public, using Boeing 727 jets. Each flight consists of around 15 parabolas, including simulations of the gravity levels of the Moon and Mars, as well as complete weightlessness.[19] This profile allows ZERO-G's clients to enjoy weightlessness with minimal motion discomfort.
In 2014, Integrated Spaceflight Services, the Research and Education partner of Swiss Space Systems (S3) in America, began its offering of comprehensive reduced gravity services on S3's Airbus A340 aircraft, as well as FAA certification of science and engineering payloads.
Aurora Aerospace in Oldsmar, Florida offers zero-g flights using a Fuji/Rockwell Commander 700. It is also used to simulate the gravity of the Moon and Mars.[21]
1) The COMSOL FEA is only solving Maxwell's differential equations to obtain the electromagnetic fields. The COMSOL FEA thermal loss analysis uses the results of the magnetic field calculations.
OK forgive me if this is total rubbish! But looking at the COMSOL FEA Thermal Loss diagram and the thermal camera image which verifies the calculated thermal losses. It strikes me that this shows that internal energy is being converted to heat at the large end but not the side walls or small end. Could it be that in these areas the RF energy is being dissipated in another way i.e. generating thrust? So could lower heat dissipation in these areas indicate energy transfer to something else unseen?
Hope that makes sense!
Mike.
You mean that the IR photons also contribute to the thrust? I believe that was already debunked, but I am just a layman.
OK forgive me if this is total rubbish! But looking at the COMSOL FEA Thermal Loss diagram and the thermal camera image which verifies the calculated thermal losses. It strikes me that this shows that internal energy is being converted to heat at the large end but not the side walls or small end. Could it be that in these areas the RF energy is being dissipated in another way i.e. generating thrust? So could lower heat dissipation in these areas indicate energy transfer to something else unseen?
Hope that makes sense!
Mike.
IULIAN:Hi,
.......snip
Iulian
Another thing to consider; From your video you have the unit on the end of a looped spring hanging from a shelf.... For the Downwards test you are trying to force the unit downwards AGAINST the natural TENSION of the spring... you need to measure just how much energy it takes to pull the spring down as much as the unit did when you powered it up.!
The original "thrust was with the aid of the spring pulling the unit upwards.
Placing the complete unit onto a balance board "like a child's see-saw, American teeter-totter" with an equal weight on the other end will enable you to perform these types of measurements
WarptechCould you perhaps use something like this? (attached)QuotePP195:
Quote from: arc on Today at 05:16 AM
Warptech
If the thruster had 2 compartments, a cylinder, where resonance was easy to establish at high Q, and a long frustum designed for maximum attenuation connected at one end of the cylinder. Between the two, there is a "shutter" that can rapidly open and close. When closed, the cylinder resonates as a cylinder. When open, energy expands into the frustum chamber where it is attenuated. After the shutter closes again, the energy in frustum attenuates and energy in cylinder recharges.... repeat. I keep looking for ways to decouple the resonant amplifier from the attenuator.QuoteFirstly I need to ask what sort of timeframes you are looking at for connecting/ disconnecting cycle,
micro_sec, milli_sec, seconds?.
How long do you think the coupling will need to be in place to create resonance inside the thruster cavity...{or are you thinking the resonance is not even needed in that chamber at all, just force fed from the attached cylinder in burst mode}. I think I see where you are going with this but more info may help clarify the desired method, and help refine a model im working on for mechanical distribution of em waves.Quote
I don't like posting my equations until I know they're right, but I believe I have shown that the force;
F ~ (alpha) * d(alpha)/dx
Where alpha is the attenuation "variable" of the waveguide. Alpha is larger for a small half-angle taper, so a long tapered pipe like a flagpole should be used for the attenuator. Alpha is variable in a frustum, it is not the same in both directions.
Also, the TC of alpha is Np/m, and it has very little effect over 1/2 a wavelength. Therefore, my thinking is that the resonant amplifier should be just a short cylinder to build up a high Q*P, then release that energy into a very long frustum pipe where all the momentum can be absorbed in the forward direction. Resonance is not needed, we want it to decay quickly, because faster decay is higher dp/dt = Force.
In reply to deltaMass, if you are only considering "reflection" then p = 0. But what happens when a wave is attenuated in a perfectly conducting circular waveguide? That energy is not lost as "heat" because there is no resistance to dissipate it.
Todd
Ok
If Im following your thought train correctly then, from my limited perspective on handling microwaves.
The generation side of the circuit requires cyclic refreshing to achieve resonance. {Unknown time-element at the moment}
Once resonance is achieved, {and not before} the energy is dumped into the "Load".
The operational functionality requires simplicity of operation.
The functionality requires the ability to alter running characteristics in realtime.
The length of the initial resonance chamber {ideally} needs to be automatically configurable {hence shawyers use of piezoelectric actuators inside his system}
The mechanical nature of the beam chopper requires simple operation but also an ability to tune in relation to time taken to achieve resonance compared with port-opening cycles. {potentially a software function to find the maximum thrust by adjusting resonance/port operation timing automatically, Microcontrollers are good for this, I use Arduino}
Thinking about the end product it may be easier engineering wise to have multiple attenuation chambers. This allows simplicity in design and beam chopper operation.
2 attenuators at 180, single beam splitter opening with weight adjusted disk to account for mass removed on one side.{less efficient model}
4 attenuation chambers equally spaced so any two are logically 180 degrees from each other, Both can be fed from the resonant chamber simultaneously via 2 opposed holes in the beam splitter. This also allows for slower rotation rate of the splitter as it has 2 holes not 1.
A variable speed rotary port opening mechanism. The shape of the beam choppers pass-through-port determines the efficiency of the opening process, square, circle, ellipse, triangular
For shorter port opening times use 2 disks counter rotating with respect to each other. {or just smaller port openings}.
Personally I tend to favour 4 attenuators because 2 will be simultaneously active while the resonator recharges to pump the other 2 attenuators. {this is also because I have no idea how long it will take to attenuate the signals in relation to achieving resonance}
? any use or.. just junk?
Terrible drawing but you get the basic concept...
(http://infinitas.co/r.d.d/project/framework/docs/em-quantum/resonant-attenuator2.png)
Just got on for a little, have a party to go to.
If there is any thrust from the EM Drive, such thrust is not affecting the natural frequencies and the mode shapes predicted by classical physics. If there is thrust such thrust involves a process which is essentially uncoupled from equations governing the natural frequency and mode shapes of the cavity.
But first, big kudos to you Dr. Rodal, big kudos! This is the premise I've been fired up about. There is thrust with no adverse change in mode shape, thermal, dang, there is nothing that shows in the COMSOL or real life tests, but it's there. Pull the plug (so to speak) out and the thrust stops. Did I get that right, is this what I've been seeing it the data from several weeks ago that you sent me on this site?
Got to go but I'm going with a good feeling.
Shell
...Shell,
Just got on for a little, have a party to go to.
But first, big kudos to you Dr. Rodal, big kudos! This is the premise I've been fired up about. There is thrust with no adverse change in mode shape, thermal, dang, there is nothing that shows in the COMSOL or real life tests, but it's there. Pull the plug (so to speak) out and the thrust stops. Did I get that right, is this what I've been seeing it the data from several weeks ago that you sent me on this site?
Got to go but I'm going with a good feeling.
Shell
I'm beginning to the think the thrust is attributed to a polarizable vacuum as extreme as that may sound. Whatever is happening is not just because of the microwaves or Maxwell's equations for the magnetic fields. It is something else. I think its more like pulling than it is thrust/pushing.I was thinking more in the lines of this: Give the QV a punch (High energy density(flux), which is what sucks up most of the power, being converted into heat. The QV seems not to absorb any energy from this process) and it will react in a way I would like to compare with the rock in a pond example, and that we can hitch a ride on the wave crests. The energy consumption of throwing the rock is also much more than the actual kinetic energy we receive by riding the wave. By tuning the cavity and the frequency we can affect the wave crests and how much energy they carry. Of course the cavity contains standing waves, but the analogy is very good. I would like to think of the QV as an extradimensional or
You got it :)
Yes, if the thrust is real (and the avalanche of replications like Iulian's make it feel more and more real) it looks to be produced by an uncoupled process.
Uncoupled processes are not uncommon, as you know actually more physical problems involve uncoupled physics or negligible amounts of coupling. Strongly coupled processes are more unusual. For example, most heat-transfer effects on structures are essentially uncoupled: thermal expansion, thermal stress, etc. The coupling in the equations of thermoelasticity is usually negligible. One can solve Fourier's equations separately, figure out the temperature distribution and from the temperature distribution calculate a thermal stress analysis. No coupling (with the exception of very thin shells, etc.).
Notsosureofit's formula is an uncoupled formula (notsosureofit please correct me if I'm wrong). The thrust force is dependent on the mode shapes. One can first calculate the mode shapes based on standard Maxwell's equations, and from them calculate the thrust force. I suppose that if the theory matures one can then refine it and explore different types of coupling and nonlinearities like in every theory (publish of perish :) ) but the main effect, to first order appears uncoupled, based on the experimental frequency and mode shape data.
...
...
If the air stream is going downwards, then everything is vice-versa from what was described above.
(http://cdn4.explainthatstuff.com/laminar-turbulent-flow-wind-tunnel.jpg)
Don't be surprised if tomorrow I read this again and I tell to myself "did I write that" ?
Paul answered a question for me back in mid April.QuoteThe high density polyethylene discs dielectric's relative permittivity is 2.27 at 2.0 GHz with a dissipation factor of ~0.0005.So that is what Eagleworks used.
Thks Aero, this looks like an extruded rod, end sliced HDPE disc: http://www.amazon.com/Density-Polyethylene-Translucent-White-Diameter/dp/B00EVCG9FS
Unfortunately the ASTM rating does not provide the permittivity or dissipation factor.
Impedance?
I also have a vague memory of someone saying that Sawyer used a T antenna parallel to the major axis of the fulstrum.
That could be another interesting breadcrumb, which may lend support to TM01 mode excitation in the Flight Thruster.
Does anybody have any other info as to Shawyer excites his Flight Thruster?
Dude. DUDE. The resonance modes for a spherical tapered cavity are solved, analytically. They are exact solutions. There is no doubt to any of them. Many simple cavity shapes have been solved for decades, and all experimental data backs these solutions very well. This is what Rodal is trying to tell you.
You cannot have a TM01 mode in any cavity. This is a waveguide mode. It is like saying 'I'm going to drive down the road at 100kph in my car, in the garage with the garage door closed'. It makes no sense. You can play semantic games and say it applies to infinitely long cavities, but that's just a waveguide.
The way you ignore salient posts with basic enclosed scientific facts makes you look like a VX Junky, and people won't take you very seriously after a while.
I'm just the messenger telling folks here what I have read many times and what Roger Shawyer has shared with me.
Ignore him if you will but his and the Chinese EM Drives are working based on his knowledge.
BTW he treats the Em Drive conic frustum as a infinite series of open circular waveguides, each with a different diameter, that cause the guide wavelength and group velocity to vary as per that diameter. Have you read what he says?
But this is a frustum. I wondered if Roval with his super mode program could trace the locus of 50+j0 ohm feed points?Impedance?Impedances of a tapered waveguide are given in Zeng and Fan.
@TheTraveller - you are nothing if not pragmatic :DQuoteShawyer & Chinese conic frustums provide thrust that matches their equations predictions.Please cite an example set of numbers that instantiates this:
1. frustum big diameter & curvature
2. frustum small diameter & curvature
3. frustum vertical height
4. operating frequency
5. predicted thrust
6. measured thrust
Can you do this?
(no dielectric please, and preferably flat ends)
???
Starting to wonder if I'm reading an updated version of Hansel and Gretel.... with all those bread crumb references ?
Seriously TheTraveler, I'd rather see you start building your setup instead of getting entangled in endless debates about R.Shawyer's merits.
With your insights and eye for detail, I'm sure your test will be much more informative then the crude (but very interesting/promising) test Iullian made.
So please man, stop digging trenches and go for what you originally planned to do : build a working model...
All this ping-pong stuff about what or what not Shawyer said/did/might have said/ could have meant...sigh... you should not take the criticism on Shawyer's texts as personal "insult"(maybe a big word).... it is all a distraction...let it go...and focus again...
You started so well... :-\
TheTraveller is doing his due-dilligence to get the dimensions correct - otherwise there will be no thrust (or there will be by just dumb luck). Verification against what has been done before is all part of the process. It's engineering and art, and I'm very impressed by what he's doing.
You need to reverse the polarity captain! Unconventional thinking is definitely left field - hence my monicker.@TheTraveller - you are nothing if not pragmatic :DQuoteShawyer & Chinese conic frustums provide thrust that matches their equations predictions.Please cite an example set of numbers that instantiates this:
1. frustum big diameter & curvature
2. frustum small diameter & curvature
3. frustum vertical height
4. operating frequency
5. predicted thrust
6. measured thrust
Can you do this?
(no dielectric please, and preferably flat ends)
Before I came on board, no one understood the Df equation, nor guide wavelength nor cutoff wavelength as used by Shawyer. It was all about classic physics and the tools derived from them showing NO THRUST will be generated. The pathway seemed to be:
If there is thrust then as our tools say no thrust, there must be new physics involved, despite Shawyer and the Chinese saying there is thrust and it can be predicted by a non classical use of the existing physics.
Instead of trying to understand what Shawyer and the Chinese are saying about how they successfully use existing physics to predict the thrust, the forum goes off to left field and dreams up ways to not need to try to understand what Shawyer and the Chinese are saying.
Which leave me, who wishes to build a Flight Thruster and have an excel spreadsheet that predicts thrust as the dimensions and frequency are varied in right field, far away from most on this thread who have chosen to play in left field and think what I'm doing is, well a sign of madness, as I will not Hi Five the desire to play in left field and ignore what Shawyer and the Chinese have shared.
Bottom line is both Shawyer and the Chinese have measured thrust on dozens of devices and that thrust is predictable from their equations. Yet those equations are totally ignored. So who is mad? Those who ignore what Shawyer and the Chinese have shared or those who ignore their results and the predictive equation they share?
For me, the pathway is to continue to talk with Shawyer, as he gives me a pat on the head and offers another bread crumb and to continue to put together a spreadsheet that allows me to calc Df and frustum length as per Shawyers shared info and equations so as to get optimal thrust at my desired operational wavelength.
With the greatest respect to others on the forum, why should I engage with equations that predict no thrust as they give me NO feedback to produce an excel spreadsheet to model what I'm attempting to do.
It is ALL about the THRUST (non dielectric) and how to model it so as I change big end and small end diameters, the Df calcs properly and from that, the length calcs properly as per the internal effective wavelength.
So many things are connected. I just finished scanning this interesting paper, not a new unknown effect (pretty pictures 8) ) and some correlations to what we're doing in harmonics and the effects they can have in a localized environment.
You got it :)
Yes, if the thrust is real (and the avalanche of replications like Iulian's make it feel more and more real) it looks to be produced by an uncoupled process.
Uncoupled processes are not uncommon, as you know actually more physical problems involve uncoupled physics or negligible amounts of coupling. Strongly coupled processes are more unusual. For example, most heat-transfer effects on structures are essentially uncoupled: thermal expansion, thermal stress, etc. The coupling in the equations of thermoelasticity is usually negligible. One can solve Fourier's equations separately, figure out the temperature distribution and from the temperature distribution calculate a thermal stress analysis. No coupling (with the exception of very thin shells, etc.).
Notsosureofit's formula is an uncoupled formula (notsosureofit please correct me if I'm wrong). The thrust force is dependent on the mode shapes. One can first calculate the mode shapes based on standard Maxwell's equations, and from them calculate the thrust force. I suppose that if the theory matures one can then refine it and explore different types of coupling and nonlinearities like in every theory (publish of perish :) ) but the main effect, to first order appears uncoupled, based on the experimental frequency and mode shape data.
For comparison (stronger nonlinearity) here's an acoustic case:
http://www.zainea.com/lowresonances.htm
So many things are connected. I just finished scanning this interesting paper, not a new unknown effect (pretty pictures 8) ) and some correlations to what we're doing in harmonics and the effects they can have in a localized environment.
http://xlab.me.berkeley.edu/pdf/245.pdf
I have some reading to do and some coffee to wash it all down with.
...
By contrast, in a closed cavity, there is a reflection at the walls, there is nothing coming out (unless we consider quantum tunneling, or heat dissipation like radiative heat transfer in a vacuum or convective heat transfer in air)
They are making an acoustic hologram.Yes, but the topology seems to be different: the correct hologram should be of a completely enclosed cavity, while the hologram in the paper has two open holes: an entry hole and an exit hole that are not present in the EM Drive (unless one invokes radiation heat transfer, convective heat transfer, perhaps general relativity, etc.)
OK, I would have to work out the math to convince myself that the "walls dissapeared". If they dissapeared we are in agreement. But to get there I need a proof, as you said :)They are making an acoustic hologram.Yes, but the topology seems to be different: the correct hologram should be of a completely enclosed cavity, while the hologram in the paper has two open holes: an entry hole and an exit hole that are not present in the EM Drive (unless one invokes radiation heat transfer, convective heat transfer, perhaps general relativity, etc.)
The topology is different. The wave packet in the EM case has the shape and phase distribution set by the cavity. If the cavity walls disappeared the trajectory of the wave packet would curve. It can't do that because the cavity is still there and has much more mass-equivalant than the wavepacket, so all you see is the reaction force.
OK, I would have to work out the math to convince myself that the "walls dissapeared". If they dissapeared we are in agreement. But to get there I need a proof, as you said :)They are making an acoustic hologram.Yes, but the topology seems to be different: the correct hologram should be of a completely enclosed cavity, while the hologram in the paper has two open holes: an entry hole and an exit hole that are not present in the EM Drive (unless one invokes radiation heat transfer, convective heat transfer, perhaps general relativity, etc.)
The topology is different. The wave packet in the EM case has the shape and phase distribution set by the cavity. If the cavity walls disappeared the trajectory of the wave packet would curve. It can't do that because the cavity is still there and has much more mass-equivalant than the wavepacket, so all you see is the reaction force.
...The only way I can see having a non-zero period-time-averaged Poynting vector in a cavity is either through a nonlinearity (example: Marco Frasca's second order nonlinearity due to GR, or van Tiggelen's 4th order nonlinearity due to magneto-chiral effect), or through an energy gradient (radiative heat transfer, etc.).
You are still too quick for me !
4-D "curve" is acceleration. The "holographic" representation is 3-D in the EM cavity. The fixed plane is time.
It should be reducible to a x,y version w/ z,t in the propagation direction (?) but again the walls must disappear for it to propagate. ?? does the Poynting vector satisfy that condition if the walls are removed ? Probably not when I try to visualize it. ?
You need to reverse the polarity captain! Unconventional thinking is definitely left field - hence my monicker.@TheTraveller - you are nothing if not pragmatic :DQuoteShawyer & Chinese conic frustums provide thrust that matches their equations predictions.Please cite an example set of numbers that instantiates this:
1. frustum big diameter & curvature
2. frustum small diameter & curvature
3. frustum vertical height
4. operating frequency
5. predicted thrust
6. measured thrust
Can you do this?
(no dielectric please, and preferably flat ends)
Before I came on board, no one understood the Df equation, nor guide wavelength nor cutoff wavelength as used by Shawyer. It was all about classic physics and the tools derived from them showing NO THRUST will be generated. The pathway seemed to be:
If there is thrust then as our tools say no thrust, there must be new physics involved, despite Shawyer and the Chinese saying there is thrust and it can be predicted by a non classical use of the existing physics.
Instead of trying to understand what Shawyer and the Chinese are saying about how they successfully use existing physics to predict the thrust, the forum goes off to left field and dreams up ways to not need to try to understand what Shawyer and the Chinese are saying.
Which leave me, who wishes to build a Flight Thruster and have an excel spreadsheet that predicts thrust as the dimensions and frequency are varied in right field, far away from most on this thread who have chosen to play in left field and think what I'm doing is, well a sign of madness, as I will not Hi Five the desire to play in left field and ignore what Shawyer and the Chinese have shared.
Bottom line is both Shawyer and the Chinese have measured thrust on dozens of devices and that thrust is predictable from their equations. Yet those equations are totally ignored. So who is mad? Those who ignore what Shawyer and the Chinese have shared or those who ignore their results and the predictive equation they share?
For me, the pathway is to continue to talk with Shawyer, as he gives me a pat on the head and offers another bread crumb and to continue to put together a spreadsheet that allows me to calc Df and frustum length as per Shawyers shared info and equations so as to get optimal thrust at my desired operational wavelength.
With the greatest respect to others on the forum, why should I engage with equations that predict no thrust as they give me NO feedback to produce an excel spreadsheet to model what I'm attempting to do.
It is ALL about the THRUST (non dielectric) and how to model it so as I change big end and small end diameters, the Df calcs properly and from that, the length calcs properly as per the internal effective wavelength.
...The only way I can see having a non-zero Poynting vector in a cavity is either through a nonlinearity (example: Marco Frasca's second order nonlinearity due to GR, or van Tiggelen's 4th order nonlinearity due to magneto-chiral effect), or through an energy gradient (radiative heat transfer, etc.)
You are still too quick for me !
4-D "curve" is acceleration. The "holographic" representation is 3-D in the EM cavity. The fixed plane is time.
It should be reducible to a x,y version w/ z,t in the propagation direction (?) but again the walls must disappear for it to propagate. ?? does the Poynting vector satisfy that condition if the walls are removed ? Probably not when I try to visualize it. ?
To be specific, let's point out that we are talking about the time-average (over an integer number of periods) of the Poynting vector being zero, as the Poynting vector itself is a non-zero harmonic function of time even as a solution of Maxwell's equations (the Poynting vector in that case having twice the frequency of the electromagnetic field frequency)....The only way I can see having a non-zero Poynting vector in a cavity is either through a nonlinearity (example: Marco Frasca's second order nonlinearity due to GR, or van Tiggelen's 4th order nonlinearity due to magneto-chiral effect), or through an energy gradient (radiative heat transfer, etc.)
You are still too quick for me !
4-D "curve" is acceleration. The "holographic" representation is 3-D in the EM cavity. The fixed plane is time.
It should be reducible to a x,y version w/ z,t in the propagation direction (?) but again the walls must disappear for it to propagate. ?? does the Poynting vector satisfy that condition if the walls are removed ? Probably not when I try to visualize it. ?
Of course, if the Poynting vector stays zero then momentum is conserved. Is that the case in a self-accelerating wavefunction ? I havn't seen it explicitly mentioned but they do claim CoM.
OK, I would have to work out the math to convince myself that the "walls dissapeared". If they dissapeared we are in agreement. But to get there I need a proof, as you said :)They are making an acoustic hologram.Yes, but the topology seems to be different: the correct hologram should be of a completely enclosed cavity, while the hologram in the paper has two open holes: an entry hole and an exit hole that are not present in the EM Drive (unless one invokes radiation heat transfer, convective heat transfer, perhaps general relativity, etc.)
The topology is different. The wave packet in the EM case has the shape and phase distribution set by the cavity. If the cavity walls disappeared the trajectory of the wave packet would curve. It can't do that because the cavity is still there and has much more mass-equivalant than the wavepacket, so all you see is the reaction force.
You are still too quick for me !
4-D "curve" is acceleration. The "holographic" representation is 3-D in the EM cavity.
Consider this, let's turn on the acoustic wave guide. Then close off the exit, closing off the Acoustic chamber. The waves entering into the closed area in the chamber would be reflected back creating another set of set of interference harmonics and possibly destructive to the pattern of the first mode. But let's say I dampened the acoustic waves on the exit door, turning them into a pattern of heat? I see heat in the patterns of the thermal images even though they are RF dissipation in the copper.
So tell me, what is the difference in a system thinking this way? We still maintain the desired mode, whether acoustic or em wave.
Notsosureofit I think we are seeing the same thing but you have a much more eloquent way of stating it, I'm more nuts... well and bolts kinda gal.
By contrast, in a closed cavity, there is a reflection at the walls, there is nothing coming out (unless we consider quantum tunneling, or heat dissipation like radiative heat transfer in a vacuum or convective heat transfer in air)
Follow the data, theory be dammed
Consider this, let's turn on the acoustic wave guide. Then close off the exit, closing off the Acoustic chamber. The waves entering into the closed area in the chamber would be reflected back creating another set of set of interference harmonics and possibly destructive to the pattern of the first mode. But let's say I dampened the acoustic waves on the exit door, turning them into a pattern of heat? I see heat in the patterns of the thermal images even though they are RF dissipation in the copper.
So tell me, what is the difference in a system thinking this way? We still maintain the desired mode, whether acoustic or em wave.
Notsosureofit I think we are seeing the same thing but you have a much more eloquent way of stating it, I'm more nuts... well and bolts kinda gal.
In this case we are ignoring the dissipation by inputting constant power to make up for it. The EM and (pressure) acoustic systems are similar in many ways.
When I try to do a thermodynamic calculation all bets are off.
I know the differences in acoustic pressure waves and EM waves gladly they both have similar phenomena of diffraction, reflection and interference and create standing waves in cavities.
Consider this, let's turn on the acoustic wave guide. Then close off the exit, closing off the Acoustic chamber. The waves entering into the closed area in the chamber would be reflected back creating another set of set of interference harmonics and possibly destructive to the pattern of the first mode. But let's say I dampened the acoustic waves on the exit door, turning them into a pattern of heat? I see heat in the patterns of the thermal images even though they are RF dissipation in the copper.
So tell me, what is the difference in a system thinking this way? We still maintain the desired mode, whether acoustic or em wave.
Notsosureofit I think we are seeing the same thing but you have a much more eloquent way of stating it, I'm more nuts... well and bolts kinda gal.
In this case we are ignoring the dissipation by inputting constant power to make up for it. The EM and (pressure) acoustic systems are similar in many ways.
When I try to do a thermodynamic calculation all bets are off.
...Concerning Feynman, I was educated in the same institution where he studied, under the same scientific principles and approach. I performed experiments since I was a freshman (I was lucky that they had started the Undergrad Research Opportunity Program and immediately engaged in hybrid chemical rocket propulsion experiments) at that institution until I got my Ph.D. Nobody at that institution performs experiments following a single researcher's publications as if they were a holy book.
I refer to Feynman:
https://www.youtube.com/watch?v=kctmPaCkV0g
"If it [theory] disagrees with experiment it is wrong."
Yet the trust of this forum seems to be to reject Shawyer and Chinese theory, which matches their experimental results, and seek some new theory outside physics when all that is needed is to listen to Shawyer and the Chinese and apply existing theory in a non conventional way.
For an engineer, seeking to model in excel what is happening as dimensions and frequency are varied, the blue sky theories on this forum provide no help, as none can take frustum dimensions and frequency and predict thrust per power applied. In fact most say there is NO THRUST.
However Shawyer's theory and equations does appear to model the thrust but those equations and explanations seem to be almost universally rejected.
Which going back to Feynman, with respect, is about as unscientific as it can get. Others claiming sloppy measurement protocols are just trying to find excuses to deal with reality and avoiding needing to accept the Shawyer and Chinese applications of current theory and thrust measurements are correct.
...
...
However Shawyer's theory and equations does appear to model the thrust but those equations and explanations seem to be almost universally rejected.
...
FYI
Here we go:
http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf
"For both TE and TM polarizations, the beams exhibit shape-preserving bending which can
have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90"
However in both the Shawyer and Chinese test data thrust is generated, which should say to you that what Shawyer is saying about his theory and what the Chinese are saying about their theory is correct and your and other conventional application of theory is not correct.Sure thing. What prevents you, therefore, from writing down those six numbers? Don't we want to look at how the predictions of Shawyer match the engineering truth?
Shawyer & Chinese conic frustums provide thrust that matches their equations predictions.1. frustum big diameter & curvature
As an engineer I question everything, I look at everything and I mean everything. I look at my coffee cup and I not only see a cup but see how it was made, I look at a radio and see the inside workings of waveforms getting amplified, rectified and how the speaker. It is the way I think. Yes Shawyer and the Chinese have ideas on how this works and so I question it, it is what I do and so do others, It's how we are built. It's not to be meant to degrade the honest work they have done or discredit them or you in any way. I respect you and them and anyone here who has the dream.
Yet the trust of this forum seems to be to reject Shawyer and Chinese theory, which matches their experimental results, and seek some new theory outside physics when all that is needed is to listen to Shawyer and the Chinese and apply existing theory in a non conventional way.
For an engineer, seeking to model in excel what is happening as dimensions and frequency are varied, the blue sky theories on this forum provide no help, as none can take frustum dimensions and frequency and predict thrust per power applied. In fact most say there is NO THRUST.QuoteFollow the data, theory be dammed
I remember in 1959 on a cold October night watching a twinkling light in the sky and knew even then the world was going to change forever, it was Sputnik. That era was started by people who followed the data, those who dreamed, those who built, those who cheered, but we all in one way or another saw the twinkling light.
Shell
FYI
Here we go:
http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf
"For both TE and TM polarizations, the beams exhibit shape-preserving bending which can
have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90"
"of the main lobe"
In our case the cavity keeps the shape from changing, so we see the force necessary to maintain the Poynting vector.
Yet the trust of this forum seems to be to reject Shawyer and Chinese theory, which matches their experimental results, and seek some new theory outside physics when all that is needed is to listen to Shawyer and the Chinese and apply existing theory in a non conventional way.
For an engineer, seeking to model in excel what is happening as dimensions and frequency are varied, the blue sky theories on this forum provide no help, as none can take frustum dimensions and frequency and predict thrust per power applied. In fact most say there is NO THRUST.
...
However Shawyer's theory and equations does appear to model the thrust but those equations and explanations seem to be almost universally rejected.
...
I reject them simply because there are numerous, glaring errors in both math and logic, in all of Shawyer's papers. It shows he has a vague engineering understanding of waveguide physics, but has very little understanding of the physical mechanisms that governs "why" those principle can be applied. As I've said, in the end, his results that F1 - F2 > 0, is correct, he's not that far off and IMO he provides a useful approximation. It is the derivation of the Thrust and his concept of how it is achieved that is incorrect. I'm sorry it's taking me so long to write up this data, but life is not easy and neither is physics!
Todd