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#1420 by flux_capacitor on 10 Sep, 2017 16:19
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Yes, it strikes me how Chinese scientific papers and patents about the EmDrive seem vague about dimensions (remember the debate about Juan Yang's cavity height and aspect ratio?). Figures not being homothetic representations of the actual device, questions about numbers being radii or diameters, absence of some critical lengths, etc. Sadly, such lack of precision about EmDrive experiments also plagues the West, as Tajmar's 2015 initial paper also mistook radii for diameters and was quite vague about the exact internal plate-to-plate height, and used a cavity designed to resonate properly above 3GHz with a commercial 2.45GHz magnetron! As if the quest to falsify the EmDrive needed nonchalantly added to the experimental difficulty and controversy.
And more strikingly, all of this while the 2015 TU Dresden report repeatedly thanks Shawyer for his guidance and advice during the project. A project which resulted in the lowest Q for an EM Drive on experimental records (much lower than the Q obtained in Do-It-Yourself experiments): Q=48, while TT posts now guidelines from "Roger" (impossible for me to independently ascertain whether these guidelines were indeed authored by Shawyer) demanding << Manufacturing tolerance should be around ±0.01mm>> and <<a Q of at least 50,000>> for such cavities, which is 1,000 times greater than the Q for the TU Dresden EM Drive done, according to the report, under guidance from Shawyer
As you met Martin Tajmar at the Estes Park conference, do you know what he had to say about the reason for such failure in the Q factor of his resonant cavity?
...
He was very open about it, and completely consistent with what he wrote in the TU Dresden report:QuoteThe Q factor measurement was then done using a spectrum analyzer (see Fig. 3a). Unfortunately, the absorption peak at the resonance we were aiming at was smaller then expected (probably also due to misalignments after soldering). We calculated the Q factor using the difference of the frequencies on both sides of the peak (f1, f2) as well as the resonance frequency f0: 8.48GHz4.2GHz45.2GHz44.2120=−=−=fffQ(1) This Q factor is of course much smaller compared to the models from Shawyer, Yang and Brady (which was in the range of 10,000 – 100,000). A much larger resonance peak appeared above 3 GHz, but as we did not have a variable frequency microwave source we had to stick to Q≈50. As our magnetron had an output power of 700 W, we expected a thrust of 98.2 μN according to Shawyer’s models. This was much higher than the resolution of our measurement equipment (< 0.1 μN) and we therefore decided to go ahead with testing and explore this low Q factor regime
Bold added for emphasis
(17) Direct Thrust Measurements of an EM Drive and Evaluation of Possible Side-Effects. Available from: https://www.researchgate.net/publication/280576708_Direct_Thrust_Measurements_of_an_EM_Drive_and_Evaluation_of_Possible_Side-Effects [accessed Sep 10, 2017].
It is striking that Shawyer advised on this work, and that Shawyer later used this Q=48 measurement in his plots of measured thrust vs Shawyer-predicted-thrust vs Q, vis-a-vis the posted guidelines demanding << Manufacturing tolerance should be around ±0.01mm>> and <<a Q of at least 50,000>> for such cavities
According to these recent guidelines of Q>50,000 not only the TU Dresden work disappears but also NASA Eagleworks and a test by SPR Ltd.in the plot shown in the presentation (UK Defence Academy) reproduced below, which have Q<10,000=104 as shown in the plot below
So the recent guidelines *<<a Q of at least 50,000>> may be interpreted "in order to get specific thrust exceeding 100 mN/kW" according to this plot
* https://forum.nasaspaceflight.com/index.php?topic=42978.msg1719903#msg1719903
Thank you for these exact quotes from Tajmar. Not being able to get a variable frequency microwave source in a professional university lab in Germany in 2015 is very disappointing, to say the least.
Not only Germany. When I think again about Paul March's conditions when he had to build the cavity for Eagleworks (a NASA-funded lab!) in his own living room at home, I feel sad for this research. Thinking also about the systematic orientation Harold White is pursuing according to his puppet theoretical QFT bias, ignoring obvious agnostic directions provided by data pointing toward AC or pulsed DC and dielectric-less operation… All this does not paint a glowing picture of this research.
The EmDrive is so much controversial therefore under-funded. But at this point it is like those professional labs have almost to resort to scissors, tape and cotton thread. Commercial microwave oven magnetrons and "supermarket oil" are not far away from this description. This is awful.
I really hope Paul March, Monomorphic and SeeShells will prove that a quality work with precise data can be done privately. Wondering what is the current state of R. W. Keyes's project BTW. -
#1421 by WarpTech on 10 Sep, 2017 16:26
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As to whether the EM Drive is an open or closed system. See Appendix B (Below) from P.W. Milonni's, The Quantum Vacuum. This derivation shows that an atom in a thermal field can experience a frictional force, proportional to the velocity.
{…}
According to your point of view, a "closed system" cannot exist (aside from the whole universe). Indeed, any electromagnetic or even any mechanical device doing some work produces and radiate heat.
The question boils down to this: Can a specific effect relying on an asymmetric heating of a closed device, coupled with the propagation of photons or charged particles within this device, can lead to a thrust force able to accelerate the device with an efficiency greater than the efficiency of a perfect photon rocket?
Said otherwise: can the effect be greater than the momentum of the infrared photons (i.e. heat) expelled out of the closed device?
My model predicts that a gradient in the power dissipation will generate a thrust or more accurately, a gravito-electric field. None of the experiments except Shawyer's have demonstrated a thrust greater than a perfect photon rocket with an output power of Pout = Q*Pin, and thrust is not continuous, it's pulsed to recharge the Q. -
#1422 by flux_capacitor on 10 Sep, 2017 16:38
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As to whether the EM Drive is an open or closed system. See Appendix B (Below) from P.W. Milonni's, The Quantum Vacuum. This derivation shows that an atom in a thermal field can experience a frictional force, proportional to the velocity.
{…}
According to your point of view, a "closed system" cannot exist (aside from the whole universe). Indeed, any electromagnetic or even any mechanical device doing some work produces and radiate heat.
The question boils down to this: Can a specific effect relying on an asymmetric heating of a closed device, coupled with the propagation of photons or charged particles within this device, can lead to a thrust force able to accelerate the device with an efficiency greater than the efficiency of a perfect photon rocket?
Said otherwise: can the effect be greater than the momentum of the infrared photons (i.e. heat) expelled out of the closed device?
My model predicts that a gradient in the power dissipation will generate a thrust or more accurately, a gravito-electric field. None of the experiments except Shawyer's have demonstrated a thrust greater than a perfect photon rocket with an output power of Pout = Q*Pin, and thrust is not continuous, it's pulsed to recharge the Q.
Gravitoelectromagnetic effects are infinitely small, except near neutron stars and so-called black holes. So if you're right, i.e. that the EmDrive induces gravitoelectric frame-dragging, and as Rodal explained a few days ago about the extreme stiffness of spacetime, this technology absolutely cannot lead to lift engines able to design flying cars hovering in Earth's gravitational field. This could turn out to be practical for deep space missions though. -
#1423 by RERT on 10 Sep, 2017 17:38
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FWIW the Cannae website is suspended at the moment, when I try to access it from the UK.
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#1424 by OnlyMe on 10 Sep, 2017 17:44
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As to whether the EM Drive is an open or closed system. See Appendix B (Below) from P.W. Milonni's, The Quantum Vacuum. This derivation shows that an atom in a thermal field can experience a frictional force, proportional to the velocity.
{…}
According to your point of view, a "closed system" cannot exist (aside from the whole universe). Indeed, any electromagnetic or even any mechanical device doing some work produces and radiate heat.
The question boils down to this: Can a specific effect relying on an asymmetric heating of a closed device, coupled with the propagation of photons or charged particles within this device, can lead to a thrust force able to accelerate the device with an efficiency greater than the efficiency of a perfect photon rocket?
Said otherwise: can the effect be greater than the momentum of the infrared photons (i.e. heat) expelled out of the closed device?
My model predicts that a gradient in the power dissipation will generate a thrust or more accurately, a gravito-electric field. None of the experiments except Shawyer's have demonstrated a thrust greater than a perfect photon rocket with an output power of Pout = Q*Pin, and thrust is not continuous, it's pulsed to recharge the Q.
I don't believe this is an accurate statement, "None of the experiments except Shawyer's have demonstrated a thrust greater than a perfect photon rocket..."
I may have missed or just don't remember the specific case, but while I admit that Shawyer has made many claims, I just can't remember any instance where he has published sufficient information about any past test, that the claims he makes can be attributed specifically and exclusively to the annomolous thrust everyone is chasing. Claims based on an unproven theoretical model aren't the same as experimental data. What we can observe and measure, always tops what we can imagine.., at least until we can experimentally observe and measure the results of what we have imagined.
Beyond that the "theory" centered on recharging or filling the frustum to a calculated Q potential, as an explanation of why pulsing or cycling a frustum on and off, creates a functional thrust, does not seem to have been proven. Even should anyone experimentally duplicate an observation consistent with his claims, the underlying mechanism, would remain "to be determined".
Shawyer and now others, may have stumbled on and continued to explore, an as yet to be clearly described and explained mechanism, resulting in even small useable thrust levels, from the introduction of EM radiation into a closed resonant cavity. That at present seems to me to be an engineering accomplishment, still waiting on a credible physical or theoretical explanation.
BTW None of the extraordinary claims of thrusts in N/Kw and greater range, even if observed behind one or more NDAs, have been publicly demonstrated, or published and confirmed by peer review. -
#1425 by Mulletron on 10 Sep, 2017 17:48
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A box of photons, which is massive ((that's what mass is, it's confined energy, we see it all around us, and within us, by various means of confinement, for example in QCD with massless gluons *(most of your mass), or the Higgs mechanism for elementary particles, or photons in a box, or photons (intentionally plural) localized as a system by space and time in a really big box)) feels the same acceleration as their container, so the relative acceleration is the same. The box, and the system of photons contained within, feel the same acceleration, in the Earth's gravitational field, so they fall at the same rate (objects of different masses fall at the same rate, including a relatively light system of massive photons and the relatively heavy copper can holding them). The cavity and the contents don't accelerate relative to each other, which is what TT says must happen. BUT there's one more level of thought, or one more step down the rabbit hole, which actually does allow the massive contents of the cavity to accelerate relative to the cavity (and the Earth), and it's the partial standing wave. There is no way the EMdrive has a perfect standing wave inside. Recall that a standing wave is the superposition of two traveling waves. You only get a perfect standing wave if the two counterpropagating waves are exactly equal in amplitude and frequency. I've looked at how the time evolution of a partial standing wave caries on, and I see a constantly changing acceleration (jerk) happening as the wave evolves. If you want to think about this from a gravitoelectromagnetic point of view, imagine slicing the EMdrive into a series of surfaces each with an area decreasing from the large end to the small end. Use the equation for gravitational induction (the one that looks similar to the Maxwell Faraday equation, but for gravity instead), with this in mind and it seems very intuitive that you'd end up with a curled nonconservative oscillating value for gEMF on the left side of the equation. Remember that acceleration and gravity are equivalent. If you have a constantly changing gravitational field, you have a constantly changing acceleration. This isn't warping of space. A changing gravitational field would exist and superimpose with the gravitational field of the surrounding environment (in the weak gravity regime which is most of the universe). A changing gravitational field should propagate out into space, which at first glance would make you think of a gravitational wave rocket, or a graviton rocket, but this doesn't fit the bill because a g rocket would do no better than a photon rocket, and if you believe the data (Eagleworks or Shawyer) an EMdrive outperforms a photon rocket, so that idea is out; what's left is considering that gravity in the linear regime obeys the law of superposition, and that an EMdrive must be adding and subtracting from the gravity from the Earth (and the gravitational influences present here coming from everywhere else). This way of thinking creates an open system and explains the apparent gain in momentum from apparently nothing non numerically, just in concept. These are all concepts I have rattling around (thanks to the paper by John Swain about gravitational transformers from last year that opened some doors), and there's no new information in all this, and may have nothing to do with reality as a whole, although each individual part is grounded in reality. It's putting together concepts that already exist into a systems thinking approach to understanding how something might work, which can be formalized using the tools that already exist. Everything with mass/energy effects spacetime and is effected by spacetime, even a tiny thing like an electron or photons, so I don't have a problem with thinking that an asymmetrical cavity resonator is capable of having useful gravitational interaction, including inducing alternating gravity itself.
Note the sudden movements here. Note the comments about changing energy density during all this. Image credit to the forum author.
https://physics.stackexchange.com/questions/265298/standing-waves-due-to-two-counter-propagating-travelling-waves-of-different-ampl
A thought experiment. Imagine by some means that we don't need to figure out why just yet (we just accept that it's happening in our minds), what would be the effect on the surrounding spacetime and orbiting satellites, if the gravitational field of the Earth were suddenly sinusoidally oscillating, and you standing there suddenly began measuring accelerations between .5g and 1.5g using an accelerometer?
Now the "just yet" part; what could possibly cause such a thing to happen? What shape would the Earth need to be in order to be doing this crazy stuff in one direction only instead of all directions?
* http://demonstrations.wolfram.com/HowTheProtonAndNeutronGotTheirMasses/
I understand the gif doesn't have fixed ends. It's just to convey a general concept.
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#1426 by Rodal on 10 Sep, 2017 18:07
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Dr Chen Yue's recent interview about the CAST EmDrive from the CCTV show is now available on YouTube. As I don't understand Chinese, I don't know though if Chen Yue speaks of the research about RF resonant cavities in another part of the show.
I activated the option to let anyone with a YouTube account add a transcript directly in YouTube. Hope someone fluent in both Chinese and English will do it.
https://www.youtube.com/timedtext_video?v=Mdcer1QQLrA&ref=share
translation posted by https://www.reddit.com/user/iiiiuuuuQuoteGoogle translate: Tracking the world's cutting-edge technology, in some technical areas to achieve technology beyond, which is aerospace technology group five in the development of communications satellites in the inevitable choice. Chen Yue 2008 graduate, came to the Space Technology Group five homes responsible for the control of communications satellite development work. Work for more than two years, he went to the courtyard to carry out communication satellite no material electromagnetic propulsion research, when the study there is still a huge controversy.
Aerospace Science and Technology Group, deputy director of the five designers Chen Yue: the most important point is that this technology may now scientific principles, not yet fully clear the case, in the project R & D, is not a great risk , Is there a reason for the existence of the wrong, this is the main controversial point.
In the space of communication satellites need to adjust the attitude and track to maintain, so the satellite will carry a large number of propellants, the traditional way of chemical propulsion is propelled by oxidation to produce thrust. And now on the satellite began to use the electric propulsion method, it is to carry the working fluid ionization, and then spray out the ion to produce thrust, the two kinds of propulsion methods are required to carry the working fluid, that is, propellant and gas.
Chen Yue: the image that is stored inside the tank inside the liquid or gas, once the use of these workers light, then the engine can no longer be used, life to the. And now we advance this way, this electromagnetic propulsion, it is as long as there is electricity, as long as the equipment can work properly, it can work, can produce thrust.
Without any technology, experience can learn from, there is no reference to any foreign information, the technology both at home and abroad, are in the technical trials of the initial stage, Chen Yue and his team is facing a huge challenge.
In order to encourage young people to innovate, Aerospace Science and Technology Group set up five special research and development fund, Dr. growth fund to give financial support, but also for the core staff for three years do not do business assessment, and personnel, laboratory equipment to give strong support to ensure that they Concentrate on doing technical research.
Chen Yue: through our hospital science and technology independent research and development fund, our independent research and development of the Fund, to support us, so that we can no heart, do not have to worry about the conditions of protection in this case, To do this thing, it can be said that this is like a hatch, if not the original hatching conditions, we will not have this progress now.
Reporters learned that, at present, on behalf of China's communications satellites to reach the international advanced level of the East Red five satellite platform a number of key technologies to achieve a major breakthrough, to be verified on the track. Dongfanghong 5 platform full star power to 30000 watts, the payload of more than 2000 kg, carrying the number of transponders to reach 120, some technical indicators than the level of developed countries. Dongfanghong 5 platform above the vast majority of products, to achieve the true sense of the localization, independent control, no longer dependent on imports.
https://www.reddit.com/r/EmDrive/comments/6z0mmt/please_help_translate_the_video_of_dr_chen_yues/ -
#1427 by demofsky on 10 Sep, 2017 23:29
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A basic question comes up for me looking at X_RaYs notional model of the new Chinese EM Drive. The assumption has always been that asymmetry is the root cause of thrust hence the fustrum. Looking at the model, it seems to optimize more for distorting modes within the cavity. The fustrum distorts modes as an obvious side effect of its asymmetry. But what if distorted modes is the main show here??
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#1428 by Rodal on 10 Sep, 2017 23:34
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A basic question comes up for me looking at X_RaYs notional model of the new Chinese EM Drive. The assumption has always been that asymmetry is the root cause of thrust hence the fustrum. Looking at the model, it seems to optimize more for distorting modes within the cavity. The fustrum distorts modes as an obvious side effect of its asymmetry. But what if distorted modes is the main show here??
If that would be so, then out the window would go the main prescription from Shawyer, for all the decades he has been writing about this: asymmetry between the big and small ends. -
#1429 by Mulletron on 11 Sep, 2017 01:02
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From what I was thinking about above, the same thing is happening in a MET (just talking about the device, not Mach effects theory). A changing energy density (capacitor being charged and discharged) is being jerked around (back and forth in the case of a MET) by a PZT. The return journey doesn't look like a good design feature to have, although if you think about it, it's inevitable in a resonant system. I'm thinking really hard about why the addition of the rubber pad (from the book Making Starships) greatly increased the thrust. That's a good way to absorb energy and reduce the return energy by reducing r. That rubber pad is dissipative. That's the asymmetry. This is an electromechanical version of the EMdrive. They're analogous.
Pics included for research purposes.
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#1430 by spupeng7 on 11 Sep, 2017 02:36
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Rodal,Dr Chen Yue's recent interview about the CAST EmDrive from the CCTV show is now available on YouTube. As I don't understand Chinese, I don't know though if Chen Yue speaks of the research about RF resonant cavities in another part of the show.
I activated the option to let anyone with a YouTube account add a transcript directly in YouTube. Hope someone fluent in both Chinese and English will do it.
https://www.youtube.com/timedtext_video?v=Mdcer1QQLrA&ref=share
translation posted by https://www.reddit.com/user/iiiiuuuuQuoteGoogle translate: Tracking the world's cutting-edge technology, in some technical areas to achieve technology beyond, which is aerospace technology group five in the development of communications satellites in the inevitable choice. Chen Yue 2008 graduate, came to the Space Technology Group five homes responsible for the control of communications satellite development work. Work for more than two years, he went to the courtyard to carry out communication satellite no material electromagnetic propulsion research, when the study there is still a huge controversy.
Aerospace Science and Technology Group, deputy director of the five designers Chen Yue: the most important point is that this technology may now scientific principles, not yet fully clear the case, in the project R & D, is not a great risk , Is there a reason for the existence of the wrong, this is the main controversial point.
In the space of communication satellites need to adjust the attitude and track to maintain, so the satellite will carry a large number of propellants, the traditional way of chemical propulsion is propelled by oxidation to produce thrust. And now on the satellite began to use the electric propulsion method, it is to carry the working fluid ionization, and then spray out the ion to produce thrust, the two kinds of propulsion methods are required to carry the working fluid, that is, propellant and gas.
Chen Yue: the image that is stored inside the tank inside the liquid or gas, once the use of these workers light, then the engine can no longer be used, life to the. And now we advance this way, this electromagnetic propulsion, it is as long as there is electricity, as long as the equipment can work properly, it can work, can produce thrust.
Without any technology, experience can learn from, there is no reference to any foreign information, the technology both at home and abroad, are in the technical trials of the initial stage, Chen Yue and his team is facing a huge challenge.
In order to encourage young people to innovate, Aerospace Science and Technology Group set up five special research and development fund, Dr. growth fund to give financial support, but also for the core staff for three years do not do business assessment, and personnel, laboratory equipment to give strong support to ensure that they Concentrate on doing technical research.
Chen Yue: through our hospital science and technology independent research and development fund, our independent research and development of the Fund, to support us, so that we can no heart, do not have to worry about the conditions of protection in this case, To do this thing, it can be said that this is like a hatch, if not the original hatching conditions, we will not have this progress now.
Reporters learned that, at present, on behalf of China's communications satellites to reach the international advanced level of the East Red five satellite platform a number of key technologies to achieve a major breakthrough, to be verified on the track. Dongfanghong 5 platform full star power to 30000 watts, the payload of more than 2000 kg, carrying the number of transponders to reach 120, some technical indicators than the level of developed countries. Dongfanghong 5 platform above the vast majority of products, to achieve the true sense of the localization, independent control, no longer dependent on imports.
https://www.reddit.com/r/EmDrive/comments/6z0mmt/please_help_translate_the_video_of_dr_chen_yues/
not being an American I am not so deeply invested in who it is that leads the field. It is however, a moment when I can remind the Americans on this forum that they should avoid the extra expense incurred when compensating (as with the Apollo program) for someone else beating you to the great leap forward. -
#1431 by Rodal on 11 Sep, 2017 02:49
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....
Beating the USA ?
Rodal,
not being an American I am not so deeply invested in who it is that leads the field. It is however, a moment when I can remind the Americans on this forum that they should avoid the extra expense incurred when compensating (as with the Apollo program) for someone else beating you to the great leap forward.
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#1432 by Mulletron on 11 Sep, 2017 02:58
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Rodal,
No, because there's a great deal of research about this kind of thing that we don't know anything about, which over time we will come to know about, because it's becoming public knowledge due to the fact that people are smart and learn things, and there's a right time and pressure (economic, socioeconomic, and military) necessary for that to happen. If you know something that nobody else understands, and it gives you an advantage, then it's obvious that you will be quiet about what you know, and what your capabilities are, until the cat is out of the bag, otherwise you're stuck holding an investment that's going to be wasted. Yes this sounds like conspiracy theory bs. I get it.
not being an American I am not so deeply invested in who it is that leads the field. It is however, a moment when I can remind the Americans on this forum that they should avoid the extra expense incurred when compensating (as with the Apollo program) for someone else beating you to the great leap forward. -
#1433 by ThinkerX on 11 Sep, 2017 02:59
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Quote
From what I was thinking about above, the same thing is happening in a MET (just talking about the device, not Mach effects theory). A changing energy density (capacitor being charged and discharged) is being jerked around (back and forth in the case of a MET) by a PZT. The return journey doesn't look like a good design feature to have, although if you think about it, it's inevitable in a resonant system. I'm thinking really hard about why the addition of the rubber pad (from the book Making Starships) greatly increased the thrust. That's a good way to absorb energy and reduce the return energy by reducing r. That rubber pad is dissipative. That's the asymmetry. This is an electromechanical version of the EMdrive. They're analogous.
Point of clarity:
Are you saying that both the EM Drive and the Woodward Mach Drive work the same way? Or close to the same way? If so, wouldn't that make the EM Drive a variant of the Woodward Mach Engine?
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#1434 by Mulletron on 11 Sep, 2017 03:06
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Quote
From what I was thinking about above, the same thing is happening in a MET (just talking about the device, not Mach effects theory). A changing energy density (capacitor being charged and discharged) is being jerked around (back and forth in the case of a MET) by a PZT. The return journey doesn't look like a good design feature to have, although if you think about it, it's inevitable in a resonant system. I'm thinking really hard about why the addition of the rubber pad (from the book Making Starships) greatly increased the thrust. That's a good way to absorb energy and reduce the return energy by reducing r. That rubber pad is dissipative. That's the asymmetry. This is an electromechanical version of the EMdrive. They're analogous.
Point of clarity:
Are you saying that both the EM Drive and the Woodward Mach Drive work the same way? Or close to the same way? If so, wouldn't that make the EM Drive a variant of the Woodward Mach Engine?
I think so. I don't know which one came first. It doesn't matter to me. -
#1435 by RERT on 11 Sep, 2017 07:34
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The Great Leap Forward the Americans were behind on was Sputnik/ Gagarin.
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#1436 by Chrochne on 11 Sep, 2017 08:12
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The Great Leap Forward the Americans were behind on was Sputnik/ Gagarin.
The fear factor was definitely present. But it helped the USA to take it seriously. It looks like same will be with the EmDrive. I sense that some people here are actually more afraid if it works rather than not. -
#1437 by Mulletron on 11 Sep, 2017 11:30
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I understand why the addition of the dielectric disc was so important now. Imagine the disc at the right side of r=.6 (or the others, this one is just optimal from the group) in the gif above.
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#1438 by PotomacNeuron on 11 Sep, 2017 14:29
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From what I was thinking about above, the same thing is happening in a MET (just talking about the device, not Mach effects theory). A changing energy density (capacitor being charged and discharged) is being jerked around (back and forth in the case of a MET) by a PZT. The return journey doesn't look like a good design feature to have, although if you think about it, it's inevitable in a resonant system. I'm thinking really hard about why the addition of the rubber pad (from the book Making Starships) greatly increased the thrust. That's a good way to absorb energy and reduce the return energy by reducing r. That rubber pad is dissipative. That's the asymmetry. This is an electromechanical version of the EMdrive. They're analogous.
Pics included for research purposes.
May I suggest that the rubber pad allowed room for the copper block to move back and forth, thus allowed more intense vibration? If so, it can be replaced with a compressed spring. -
#1439 by Rodal on 11 Sep, 2017 15:19
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The purpose of this very thin rubber under ~3000 psi compressive stress is to provide a more uniform contact stress distribution between the brass mass and the holding bracket, so that there is uniform contact between the mating surfaces, and accommodate misalignment, imperfectly machined surfaces, and smooth the stress distribution.From what I was thinking about above, the same thing is happening in a MET (just talking about the device, not Mach effects theory). A changing energy density (capacitor being charged and discharged) is being jerked around (back and forth in the case of a MET) by a PZT. The return journey doesn't look like a good design feature to have, although if you think about it, it's inevitable in a resonant system. I'm thinking really hard about why the addition of the rubber pad (from the book Making Starships) greatly increased the thrust. That's a good way to absorb energy and reduce the return energy by reducing r. That rubber pad is dissipative. That's the asymmetry. This is an electromechanical version of the EMdrive. They're analogous.
Pics included for research purposes.
May I suggest that the rubber pad allowed room for the copper block to move back and forth, thus allowed more intense vibration? If so, it can be replaced with a compressed spring.
These are the reasons why gaskets are used when fastening mating surfaces: it is commonplace. One can find discussions of such gaskets in the proceedings of the American Society of Mechanical Engineers (ASME) and the American Institute of Aeronautics and Astronautics (AIAA). The ASME has regulations for nuclear powerplants on fastening mating surfaces.
From contact mechanics it is known that when you fasten two bodies together you will have stress concentrations around the mating surfaces where the (fastener) forces are applied. It is a thin rubber gasket between the mating surfaces (the holding bracket and the brass mass) to ensure good contact between the mating surfaces throughout the contact surface. The screws are torqued such that the piezoelectric plates of the sandwich stack are compressed to industry standards (around 3,000 psi) since these piezoelectric plates need to be under initial compressive stress to perform (as is usual in Langevin stacks in piezoelectric transducers) because they are sintered ceramics (PZT) that are very brittle and cannot properly function under tensile stresses.
