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#1400 by frobnicat on 18 Mar, 2015 22:22
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Quote from: Star-Drive
one 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.
...
"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.
...
That is not really stating explicitly that any experiment showed such thrust toward the big end. Attached "resonant mode map" is not an experimental one. It just shows the theoretical result of a calculation. If we are to interpret the blue plot on top as thrusting toward small end when above 0 and thrusting toward the big end when below 0, then this is contradicting the theoretical formula that the TM modes results published so far all thrust toward small end as well as the TE modes.
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 ?
In any case, the following plot is not experimental proof of anything.
biggerQuote 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.
Basically I agree.
But can is a can of worms. Star-Drive already stated that "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." which is a theoretical model map... The end of the sentence immediately transforms can into could in my brain. Am I badly wired ? A clear answer would be that the EM Drive has indeed been experimentally recorded running with the thrust force directed towards the big base (with such or such conditions).
I'm not splitting hairs for pleasure. If I learned one thing in those discussions is the degree of misunderstanding that can (does) creep into the arguments and projected motivations. As for the 0 force of "unconstrained thermal expansion" discussions we had. It seems you still think that I was arguing that for vacuous intellectual righteousness reasons, that in fact I believed, like you, that the subject wasn't actually important in the context of EMdrive discussions. Actually I believed that the subject was important in the context of EMdrive. Then (later) I made quantitative assessment of the unrestrained thermal expansions recoil momentums, and am now convinced that it is not, quantitatively, significant. Paul March is apparently still struggling to explain some of the thermal aspects of signal by recoil effects. So I know I'm not the only one to have taken the matter of unrestrained thermal expansions recoil momentums as, a priori, important. Oh, and while I'm at it, the Oakridge paper explaining some of the results of ME drives on pendulum by classical thermal expansion recoil effects (synchronised on many oscillating periods: not applicable for Eagleworks results) makes perfect sense to me, their equations are impeccable
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#1401 by frobnicat on 18 Mar, 2015 22:37
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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.
So maybe I'm badly wired. But please take care to read carefully the later post by Paul March where the only experimental data about "reversal" is disclosed. See the orientations of the frustum on the second and third attached pictures ? The plot with the reversed signal just follows, it was taken within an hour of the second picture (time stamps). Same qualifier "reversed" is used. Also in the same phrase : "...the reversed test setup drawing and the best reversed thrust plot obtained...". The drawing of setup shows small end toward right, this is a 180° turn from the other experiments, the "reversed" thrust plot is therefore quite clearly stated as being done with a setup with small end to the right, reverse as in "turned 180°", my understanding is that the plot is not about a thrust toward big end. Would seem rather contrived or carelessly misleading otherwise.
The previous comment you quote is more ambiguous. But I hope you understand the reasons of my understanding (even if not sharing it) as far as the only experimental "reversed" result published so far is concerned.
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#1402 by Notsosureofit on 18 Mar, 2015 22:47
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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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#1403 by Rodal on 18 Mar, 2015 23:25
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....
Welcome to NASA SpaceFlight EM Drive Developments' thread
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#1404 by frobnicat on 18 Mar, 2015 23:26
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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.
Actually the calculated chart does predict thrust toward small end for TE012 (blue plot up) but the TM212 is nowhere to be seen (is it ?). The original article (anomalous thrust...) shows only thrusts toward small end, including TM211, that do appear on the calculated chart as thrusting toward big end (blue plot down) : so yes some experiments seem to invalidate the used formula.
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#1405 by Notsosureofit on 19 Mar, 2015 00:18
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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.
Ahhh, I see, I've been reading the (small print) TM211A as TM212A,... my mistake. I might add that I never get any forces out of ExB calculations, that's why I like plain GR Equivilance, but only time (and more experiments) will tell. -
#1406 by ThinkerX on 19 Mar, 2015 00:26
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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.
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#1407 by Rodal on 19 Mar, 2015 00:29
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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.
We should resist a rush to judgement (this goes for Mr. Fronicat as well), until Paul March clarifies his experimental program.
Were experiments conducted that showed a force towards the small base of the truncated cone for a given exciting frequency and a force in the opposite direction, towards the big base of the truncated cone at a different exciting frequency ?
Are there "force vs. time" (really "position vs. time") data plots for the EM Drive showing a force towards the big end? If yes, which plots correspond to the experiments where the force was directed towards the big base of the truncated cone?
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#1408 by aero on 19 Mar, 2015 00:41
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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.
A look at the aspects of the EM thruster hypotheses discussed.
On the 250 odd pages of this and the previous thread, we have discussed many hypotheses related to the EM thrusters. This is my poor attempt to outline those topics as related to the detected thrust. First, these topics fall into two broad categories, real and artifact. Others may have a more logical summary categorization.
My categories are:
I. Artefact -
A. Thermal - I will not attempt to break down this. Many considered thermal artifacts.
B. Device - Includes analysis of Eagleworks torsion pendulum/chamber.
1.
2. Attraction of cavity to chamber - Nullified by Eagleworks open air experiment.
II. Real -
A. Thrust magnitude -N/Watt- factors
1. Resonance modes
2.
3.
B. Momentum exchange mechanism
1. Classic known physics
i. Shawyer theory
ii. Chinese theory
iii. Evanescent Wave theory
iv. Dynamic Casimer theory
v. Others I don't recall at the moment.
2. Classic unknown physics
i. Casimer related
ii. Evanescent wave related
iii. Mach effect (GR + gravinertial Wheeler-Feynman field, i.e. inertia)y
3. New Physics
i. Quantum Vacuum -Quantum plasma theory
ii. MiHsC theory
iii. Dark Matter - Nullified based on insufficient density of DM.
iv. Scalar–tensor theory (GR + scalar field)
edit Add: GR, DM,
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#1409 by Notsosureofit on 19 Mar, 2015 00:51
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Well, under classic unknown, you can put General Relativity..
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#1410 by Rodal on 19 Mar, 2015 01:03
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But it is interesting that Roger Shawyer reports forces in different directions (sometimes towards the small end and sometimes towards the big end) for different experimental conditions.
Are these differences really due to the Poynting vector ExB being different for different mode shapes?
(Shawyer -unlike NASA Eagleworks- did not report mode shapes computational studies)
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. This seems to give a death knell to mechanistic conjectures like Mr. Frobnicat's mechanistic conjecture. -
#1411 by aero on 19 Mar, 2015 01:49
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Re. Hypotheses looked at - where does our lengthy discussions of dark matter fit?
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1347946#msg1347946 -
#1412 by Stormbringer on 19 Mar, 2015 01:53
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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://www.sciencedaily.com/releases/2015/03/150306091617.htm
http://phys.org/news/2015-03-mini-black-holes-lhc-parallel.html -
#1413 by zen-in on 19 Mar, 2015 02:26
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Quote from: Star-Drive
one 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.
What I would like to see are thrust waveforms with the cavity position turned 180° around. This is what I thought was meant by reverse thrust waveforms. If the thrust waveforms with the cavity position turned 180° around are in the opposite direction and have the same absolute magnitude as the others, given the same RF power and dielectric insert, then it would go a long way towards proving this device actually does produce thrust. Sorry for being such a doubter but that just comes with old age.
I don't believe further claims of reverse thrust when different modes are used invalidates any alternative theory of the anomalous thrust because all the waveforms seen represent very small TP rotations. The only way alternative theories can be invalidated is by performing counter experiments and baseline tests such as:
1) Measure the error thrust by using a dummy load under the same conditions as a just completed thrust test.
2) Performing controlled tests with the cavity reversed and forward
3) Apply heat to the inside of the cavity and record any change in the LDS reading.
4) Determine the sensitivity of the LDS to changes in CM. What affect do small ( ~arcSec ) rotations of the TP beam, with the TP position fixed, have on the LDS reading?
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#1414 by aero on 19 Mar, 2015 04:16
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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://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." -
#1415 by ThinkerX on 19 Mar, 2015 04:39
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Quote
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."
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.
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#1416 by Stormbringer on 19 Mar, 2015 04:47
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Axions are not the only game in town. What about nexus gravitons? That looks like it could produce a type or ersatz thrust but it's beyond me how the RF thing would coax a high energy nexus graviton into shedding lower energy ones. If it did a thrust like thing might happen due to the space/time expansion property postulated in that article. I mean what do the things (should they even exist) interact with that an engineer can get their hands on with essentially little better than garden shed workshop level gear? Does the theory allow for EM interaction? thermal? Some sort of emergent entity like a phonon, etc?
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#1417 by RotoSequence on 19 Mar, 2015 06:26
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Quote
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."
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.
If I recall correctly, the Dark Matter explanation was quickly ruled out in this thread, because the operating frequencies of EM drives are some of the most extensively studied portions of the electromagnetic spectrum, and, IIRC, one of the first places people looked for signs of Dark Matter's existence. If it was responsible for the functionality of EM drives at the frequencies tested, shouldn't we have seen dark matter before people started looking at EM drive? -
#1418 by Mulletron on 19 Mar, 2015 08:30
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I promised to post some material about cavity optomechanics here:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1343469#msg1343469
This subject covers a wide swath of applications from suppressing Brownian Motion of atoms to detecting gravitational waves. I'm not concerned with most of those applications besides learning the basic concepts and applying them in the right direction.
It doesn't take too much of a stretch of the imagination to see where Emdrives could fit in with this when you consider that matter is known to couple with electromagnetic radiation on both the real and vacuum side. The transfer of momentum from the quantum vacuum interaction (which conserves momentum) has been elucidated, what is left is to find proof that this, combined with resonant cavity physics, can make something move.....a thruster.
Admittedly, it hasn't been written in the literature yet that one can build a device which moves uni-directionally using these concepts. This part of what I've been saying hasn't been written as far as I can tell, hence the wall I've hit looking for further pre-existing science. This is the holy grail that I'm searching for.
Get ready for information overload, I'm not posting everything I have, just the primers:
http://arxiv.org/abs/1303.0733 (a very broad basic overview of the field)
http://aspelmeyer.quantum.at/docs/82/downloads/revmodphys.pdf (published version of above)
http://www.cqom-itn.net/wp-content/uploads/2013/02/Diavolezza2013-Nunnenkamp.pdf (good overview)
http://authors.library.caltech.edu/32352/1/PTO000029.pdf (easy read)
http://www.umich.edu/~mctp/SciPrgPgs/events/2010/MQSS10/Talks/Stamper-Kurn_Optomechanics.pdf
http://ultracold.physics.berkeley.edu/pubs/ThierryThesis.pdf (very exhaustive thesis)
http://dash.harvard.edu/bitstream/handle/1/11158247/Woolf_gsas.harvard_0084L_10812.pdf?sequence=1 (another very exhaustive thesis)
http://www.academie-sciences.fr/activite/cr/CRPhys_thema_micro.pdf (foreword is very helpful)
http://www.cqom-itn.net/wp-content/uploads/2013/02/Diavolezza-2013-Kippenberg.pdf
Little more focused:
http://aip2014.org.au/cms/uploads/presentation/ray%20simmonds.pdf (close but no cigar)
http://phys.scichina.com:8083/sciGe/fileup/PDF/14yg2276.pdf (getting warmer)
http://arxiv.org/abs/1308.4503 (trapping dielectric spheres)
During all this research I've found that Caltech is heavily involved in cavity optomechanics, and the LIGO experiment. I suspect, that if the Emdrive effect is in fact real, it will be discovered independently by researchers like this by accident.
https://www.vahala.caltech.edu/Research/Nonlinear
https://www.vahala.caltech.edu/Research/Optomechanics
http://www.ligo.caltech.edu/
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#1419 by flux_capacitor on 19 Mar, 2015 10:10
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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.
May you modify/add:
2. Classic unknown physics
iii. Mach effect (GR + gravinertial Wheeler-Feynman field, i.e. inertia)
and
3. New Physics
iv. Scalar–tensor theory (GR + scalar field)
"Classic unknown physics" and "New Physics" should be under the same bullet point IMO.
As for Mach effects (M-E): Ron Stahl, who is willing to replicate Woodward's experiments, stated about the EmDrive:QuoteI 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.
