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. 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.The high-power engineering can be done after the basic principles involved are understood.
@TheTraveller 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.
Quote from: R.W. Keyes on 05/07/2015 06:17 pmI'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.
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).
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.
Quote from: deltaMass on 05/07/2015 10:00 pm@TheTraveller 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.http://www.alibaba.com/product-detail/2014-promotional-bldc-motor-magnetic-bearing_1803241008.htmlmight 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)?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_motorTo 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
Quote from: Bubs on 05/08/2015 02:23 amCan 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_motorTo do a proper measurement, the Earth's magnetic field should be canceled around the experiment using this setup:http://en.wikipedia.org/wiki/Helmholtz_coilAssuming 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
...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.)