-
#1040 by Oakey on 07 Apr, 2016 13:52
-
Also the full set up looks like microwave or rf guide passes through top of assembly to the hole when assembled. That's how I would do it. Excited from tapered end?
I've marked in red the coax cables. Again we see what looks like two ports into the cavity on the side walls. I do not see any indication that this is being excited from the small tapered end.
Could be! Although it does look like the top balance and bottom balance are needed. It could be a coax that is connected to the balance arm at the top. There by using the liquid refrigerant as boyancy and measuring difference in weight from both balances. If it is non propellant drive shouldn't the difference show up differently? -
#1041 by Rodal on 07 Apr, 2016 14:25
-
would this still be the case if there was no container and a relatively harmless 60GHz was being used?
What I am trying to ask is, can a resonance be maintained between parallel plates without sides?
I shrank the wedge, removed two of the side walls, and ran a sweep from 60 to 70Ghz. All I got was this same e-field pattern. None of the more interesting modes were present. Basically it's just an antenna at this point.
Thank your for continuing to post these very enlightening computer runs. When you state <<I shrank the wedge>>, what is the size of the "shrunk" wedge run with a sweep from 60 to 70Ghz, compared to the Shawyer-original wedge geometry?
Thanks
-
#1042 by Monomorphic on 07 Apr, 2016 14:30
-
When you state <<I shrank the wedge>>, what is the size of the "shrunk" wedge run with a sweep from 60 to 70Ghz, compared to the Shawyer-original wedge geometry?
It's a lot smaller! Units are in cm. At 1cm high, this cavity is smaller than a dime.
-
#1043 by X_RaY on 07 Apr, 2016 18:46
-
Good explanation of the definition of laser-modes in general, may be interesting for TT and others.
http://www.networxsecurity.org/de/mitgliederbereich/glossary/t/transverse-mode.html
-
#1044 by Rodal on 07 Apr, 2016 18:59
-
Good explanation of the definition of laser-modes in general, may be interesting for TT and others.
http://www.networxsecurity.org/de/mitgliederbereich/glossary/t/transverse-mode.html
Yes, these are TEM modes, Hermite–Gaussian modes, neither electric nor magnetic field in the direction of propagation, existing in optical resonators.
This is the kind of problems for which MEEP was meant to be used (optical problems)
https://en.wikipedia.org/wiki/Gaussian_beam#Hermite-Gaussian_modes
and here are the waveguide optical fiber modes:
Only TE (magnetic field in the longitudinal direction) or TM modes (electric field in the longitudinal direction) can take place, as a resonant solution (high Q) of Maxwell's equations in the EM Drive closed metallic cavity used in Shawyer's experiments.
-
#1045 by Rodal on 07 Apr, 2016 19:08
-
Ok....The wavelenght must be exactly dividible with the distance between reflectors.
The problem with precisely reading "exactly divisible" in that statement is that, inside a cavity:
* The wavelength inside a cavity is different from the wavelength in free-space. The wavelength inside a tapered cavity (the EM Drive) is not uniquely defined. The wavelength instead of being a constant, it is a function of the longitudinal location direction of the tapered cavity.
There is not a single wavelength, but the wavelength is a continuous function of the longitudinal distance from the big end to the small end, such that the wavelength increases monotonically, smoothly and continuously from big end to small end.
Here is a typical picture for an EM Drive, where the wavelength changes smoothly and continuously by ~8%
...
Therefore, since there is not a unique wavelength, but an infinity of wavelengths, how is the statement
<<.The wavelenght must be exactly dividible with the distance between reflectors.>>
to be interpreted for a tapered cavity like the EM Drive where the wavelength increases monotonically by 8% from big end to small end ?
In any case the aim is to get reflective wave eliminating transverse component so that electric inductive disturbances will disappear.
Maybe I have totally wrong practical ideas. I have no experience on this kind of radiation cavities.
Hm. Did you take account that in g-drive scheme the "plates" are spherical mirrors, concave and convex?
...
What is your opinion of Trunov's paper on the EM Drive, also involving general relativity ?
See attachment (I enclose the English language version. There is also an original Russian version if you find that language easier to read)
GENERAL RELATIVITY AND DYNAMICAL MODEL OF ELECTROMAGNETIC DRIVE
Трунев Александр Петровичк.ф.-м.н., Ph.D., директор
Alexander Trunev
Cand.Phys.-Math.Sci., Ph.D., C.E.O.
Научный журнал КубГАУ, №116(02), 2016 года
-
#1046 by Rodal on 07 Apr, 2016 19:54
-
...Breaking my silence for once. A "over unity" scheme does not need constant acceleration with constant power, it needs constant force with constant power input. Because acceleration is relative (what you say of acceleration in SR depends on reference frame, from the spacecraft itself there is no decrease in acceleration at constant force...) there is always a great confusion with interpretation in delta kinetic energy. And a force can be applied at constant velocity, no acceleration, as in a tractor pulling a plow at constant velocity (wrt to ground), as in a turbojet thrusting for a plane moving against aerodynamic drag at constant velocity (wrt to air mass). ...
Professor Frobnicat, one of the great though-models I remember you made was the one of a road, and that the EM Drive does not have a road with friction for a vehicle to travel on.
I like you to consider Quantum Vacuum Friction. If it would exist, then, such friction could be exploited for propulsion:
https://www.newscientist.com/article/mg20927994-100-vacuum-has-friction-after-all/
http://physicsworld.com/cws/article/news/2009/mar/17/quantum-friction-does-it-exist-after-all
https://www.researchgate.net/publication/230902810_Quantum_vacuum_friction
http://arxiv.org/pdf/1504.02204.pdf
Your opinion on this hypothesis ?
-
#1047 by Eusa on 07 Apr, 2016 20:15
-
I have absolutely no russian language skills.
Ok....The wavelenght must be exactly dividible with the distance between reflectors.
The problem with precisely reading "exactly divisible" in that statement is that, inside a cavity:
* The wavelength inside a cavity is different from the wavelength in free-space. The wavelength inside a tapered cavity (the EM Drive) is not uniquely defined. The wavelength instead of being a constant, it is a function of the longitudinal location direction of the tapered cavity.
There is not a single wavelength, but the wavelength is a continuous function of the longitudinal distance from the big end to the small end, such that the wavelength increases monotonically, smoothly and continuously from big end to small end.
Here is a typical picture for an EM Drive, where the wavelength changes smoothly and continuously by ~8%
...
Therefore, since there is not a unique wavelength, but an infinity of wavelengths, how is the statement
<<.The wavelenght must be exactly dividible with the distance between reflectors.>>
to be interpreted for a tapered cavity like the EM Drive where the wavelength increases monotonically by 8% from big end to small end ?
In any case the aim is to get reflective wave eliminating transverse component so that electric inductive disturbances will disappear.
Maybe I have totally wrong practical ideas. I have no experience on this kind of radiation cavities.
Hm. Did you take account that in g-drive scheme the "plates" are spherical mirrors, concave and convex?
...
What is your opinion of Trunov's paper on the EM Drive, also involving general relativity ?
See attachment (I enclose the English language version. There is also an original Russian version if you find that language easier to read)
GENERAL RELATIVITY AND DYNAMICAL MODEL OF ELECTROMAGNETIC DRIVE
Трунев Александр Петровичк.ф.-м.н., Ph.D., директор
Alexander Trunev
Cand.Phys.-Math.Sci., Ph.D., C.E.O.
Научный журнал КубГАУ, №116(02), 2016 года
I noticed at glance that the claim is mass-reducing - my claim is space-reducing and hence the increace of apparent non-inertial mass.
Maybe this difference is due to my understanding that space fragments are streaming to masses, there are no pulling force signals from gravitating body. The gradient of space tension of vacuum quanta affect accelerations. -
#1048 by CW on 07 Apr, 2016 21:10
-
...Breaking my silence for once. A "over unity" scheme does not need constant acceleration with constant power, it needs constant force with constant power input. Because acceleration is relative (what you say of acceleration in SR depends on reference frame, from the spacecraft itself there is no decrease in acceleration at constant force...) there is always a great confusion with interpretation in delta kinetic energy. And a force can be applied at constant velocity, no acceleration, as in a tractor pulling a plow at constant velocity (wrt to ground), as in a turbojet thrusting for a plane moving against aerodynamic drag at constant velocity (wrt to air mass). ...
Professor Frobnicat, one of the great though-models I remember you made was the one of a road, and that the EM Drive does not have a road with friction for a vehicle to travel on.
I like you to consider Quantum Vacuum Friction. If it would exist, then, such friction could be exploited for propulsion:
https://www.newscientist.com/article/mg20927994-100-vacuum-has-friction-after-all/
http://physicsworld.com/cws/article/news/2009/mar/17/quantum-friction-does-it-exist-after-all
https://www.researchgate.net/publication/230902810_Quantum_vacuum_friction
http://arxiv.org/pdf/1504.02204.pdf
Your opinion on this hypothesis ?
This idea is something that I've been mulling about for a long time. Basically, in my imagination, spacetime is analogous to a perfectly smooth, frictionless surface. Wanting to propel oneself without expelling mass or photons, is like a cow on glaze trying to move. It just doesn't happen, she can't couple with the ice. I see CoM as an effect akin to superconductivity, just for any type of matter or particle. What moves, keeps on moving. Spacetime fabric as matter/wave superconductor. What, if we could at least temporarily break or disturb the 'superconductivity' of spacetime, or at least lower it?
So, novel propulsion device would need IMO to (temporarily) cause 'wrinkles' in this perfectly smooth, frictionless surface to give it a way to couple with the spacetime fabric. Obviously, the spacetime fabric would display novel behavior as a reaction to 'rubbing against it'. Perhaps this would cause spacetime compression waves emanating from such a device? Could evanescent waves and virtual particles be very shortlived 'wrinkles or roughed up spots in spacetime' ?
Half OT, but take a look at this:
http://nextbigfuture.com/2016/03/tiny-mems-gravity-sensor-could-detect.html#solidopinion
Nice MEMS gravity sensor there .
-
#1049 by Rodal on 07 Apr, 2016 21:27
-
Google Russian translation (not all that good): http://tinyurl.com/zvr7at3
In my post ( http://forum.nasaspaceflight.com/index.php?topic=39772.msg1512743#msg1512743 ) I had already attached the official translation to English by the author ( http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39772.0;attach=1108681 ), which is preferable to the Google translation to English from the Russian you linked to. My question to Eusa was whether he would have preferred the Russian version (this one:
http://ej.kubagro.ru/2015/10/pdf/61.pdf
) instead of the official English version I attached to my post. He answered no.
-
#1050 by otlski on 08 Apr, 2016 01:07
-
Otlski,
am very impressed by the measurement setup you recommend in this post. The 60 GHz experiment I am building has a mass of about 800g including batteries and casing. The frustum will be tiny with a wavelength of just 5mm so it has a very low predicted output.
My question is this, could the linear air bearing in the setup you suggest, be replaced by a solid vertical flexible bearing mounted on a rigid upright? This would allow slight rotary motion of a horizontal beam about the vertical axis of flexure. Preload could then be against the flex so that the hinge axis remains vertical and there is one less moving part.
I am having a hard time picturing what you mean. I am being dense today; a sketch would help. I am imagining three possibilities. First, a hanging four link suspended platform. Second a four link platform where the links are in compression. Third, a single link (like a grandfather clock pendulum) suspending a platform.
The first would be the preferred configuration because being in tension, the links can be made thin. Long and limber is the key although you need to use rectangular plate like flexures to restrain the device to a single axis of response.
The second is not as desirable because the flexure thickness has to be enough to prevent buckling. Though you only need to support 800 grams I would imagine the suspension would be suitably scaled (think small) to suit your payload.
The third, the non four link device would undesirably be the most responsive to frustum CTE as the shift in CG would make the pendulum want to move to keep the new CG under the pivot. This would yield false thrust indications. The four link would be more resistant.
The need to keep it very limber is that in the ideal "permanently calibrated" system the majority of the system's stiffness should come from the transducer and not from the suspension components. Better linearity will follow.
Whether the above would work in your case highly depends on what thrust you expect/achieve, and how well implemented your apparatus is. Tell me, what do you hope to see for thrust and what transducer would you use to measure it?
All this assumes that you would be making a non-moving instrument as I described. In fact this whole post assumes I am picturing correctly what you meant. I hope so... -
#1051 by FattyLumpkin on 08 Apr, 2016 01:39
-
Change of subject (again), to all to observant geometry folks out here: has anyone tried to extrapolate the dimensions of the EWL frustum?... (see attached) ....I came up with: SD = 13.186 cm, LD = 30.95 cm and a Height of approx. 22 cm. ---done with out computerized methods. Anyone? FL
-
#1052 by Monomorphic on 08 Apr, 2016 01:49
-
Change of subject (again), to all to observant geometry folks out here: has anyone tried to extrapolate the dimensions of the EWL frustum?... (see attached) ....I came up with: SD = 13.186 cm, LD = 30.95 cm and a Height of approx. 22 cm. ---done with out computerized methods. Anyone? FL
I just wanted to point out the $8,000+ handheld spectrum analyser (circled in red).
http://www.keysight.com/en/pcx-x205205/fieldfox-and-hsa-handheld-spectrum-analyzers?nid=-32505.0&cc=US&lc=eng
Looking at purchasing a USB spectrum analyser myself. Can't go much further without one.
-
#1053 by FattyLumpkin on 08 Apr, 2016 02:37
-
Going into Orbit? Go with10x10x11.35cm Cubesat at---> TM212, 6.9122 GHz, 4.722 Watts to make
25.5 microN. Dimensions: BD=10 cm, SD=5.619 cm and a Height of 8.182 cm.
Please yell if I did the math wrong! , FL -
#1054 by spupeng7 on 08 Apr, 2016 02:49
-
Whether the above would work in your case highly depends on what thrust you expect/achieve, and how well implemented your apparatus is. Tell me, what do you hope to see for thrust and what transducer would you use to measure it?
If Dr Rodal is correct I cannot hope to see more than nano Newtons from a 60GHz frustum, not practically measurable. Not keen to abandon what has been an expensive build I feel I should take the opportunity to try something new, such as an array of resonators. Local RF engineers have been understandably derisory so I have a long list of questions I would like to ask.
Yes, I will try to construct my questions better, meantime please let me know if this is the wrong forum to bring such questions to. As for transducers, that depends what is available at the time.
-
#1055 by Monomorphic on 08 Apr, 2016 03:01
-
Going into Orbit? Go with10x10x11.35cm Cubesat at---> TM212, 6.9122 GHz, 4.722 Watts to make
25.5 microN. Dimensions: BD=10 cm, SD=5.619 cm and a Height of 8.182 cm.
Please yell if I did the math wrong! , FL
Here is my run using those dims.
-
#1056 by SeeShells on 08 Apr, 2016 03:15
-
This is a lot of bang for the buck.
http://www.ebay.com/itm/USB-RF-Spectrum-Analyzer-3-3GHZ-/272201346705
I have one and for the price it's not bad.
ShellChange of subject (again), to all to observant geometry folks out here: has anyone tried to extrapolate the dimensions of the EWL frustum?... (see attached) ....I came up with: SD = 13.186 cm, LD = 30.95 cm and a Height of approx. 22 cm. ---done with out computerized methods. Anyone? FL
I just wanted to point out the $8,000+ handheld spectrum analyser (circled in red).
http://www.keysight.com/en/pcx-x205205/fieldfox-and-hsa-handheld-spectrum-analyzers?nid=-32505.0&cc=US&lc=eng
Looking at purchasing a USB spectrum analyser myself. Can't go much further without one. -
#1057 by FattyLumpkin on 08 Apr, 2016 07:13
-
I was able to locate two charts that are in better shape than Yang's. Enjoy!
-
#1058 by FattyLumpkin on 08 Apr, 2016 07:31
-
Monomorphic, I calculated a frequency of ****6.9122-6.9196 GHz**** to run in the Cubesat frustum (not 2.45). I had no idea you were going to perform a sim on it. Perhaps you can try the above mentioned frequency(s). If I did the math correctly it should look quite good (a scaled down version of NASA's TM212, 91.2 micro-Newton model). Thanks for your time!
, FL
-
#1059 by Rodal on 08 Apr, 2016 11:41
-
I was able to locate two charts that are in better shape than Yang's. Enjoy!
We need to emphasize that the charts attached to your post are only correct for a cylindrical cavity with constant circular cross-section in the longitudinal cross-section.
But for that case, there is a simple closed-form formula ( https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) for the natural frequency fmnp (the eigenfrequencies):
TM Modes:
TE Modes:
with m,n,p being the mode numbers, R is the internal radius of the cylindrical cavity, L the internal length, c is the speed of light in vacuum; and μr and εr are relative permeability and permittivity of the cavity filling respectively.
the roots of the Bessel functions, Xmn , X'mn are tabulated, within 15 digits here:
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
Due to the availability of calculators and computers nowadays, the use of the equation obviates the use of the charts because the equation can give more accurate values than having to interpolate values from the chart.
However, Yang's cavity and the EM Drive in general is not a cylindrical cavity, but instead it is a frustum of a cone, with varying diameter along the longitudinal direction.
For resonance of a frustum of a cone there is no such closed-form expression, and therefore the charts you attached, or the equations, can only be used in an approximate way (to within 10% of the natural frequency for frustums of a cone not too different from a cylinder), for example using an average diameter
D = (Dbig + Dsmall )/2
and average radius
R= (Rbig + Rsmall )/2
= D/2
, FL