Quote from: SeeShells on 07/04/2015 11:10 pmShellI'll be the first to admit there is something going on and it deserves further testing. I have never advocated, and never will, that testing should be abandoned. However, I have always been clear that I feel the likelihood that that something is propellantless thrust to be very low. Finding the exact quirk that gives the appearance of propellantless thrust is a worthwhile scientific endeavor in it's own right though.QuoteI believe there is enough empirical data in such widely varying test beds and that this is just enough out of the noise of chance that there is something going on and it deserves further testing.This right here is probably where you and I, and everyone else who has a different take on the emdrive from 100% likelihood to 0% likelihood, differ. When the emdrive first popped back into the news last august, I always heard the word replication being thrown around. Nasa has replicated a propellantless drive! It was replicated by the Chinese! UK inventor has drive replicated by Nasa and Chinese Labs! These were the kinds of headlines I saw. However, when you actually read through the individual papers, something practically explodes out at you. None of the experiments are actually replications of any of the others:The chinese got higher thrust from lower Q than Shawyer - goes against Shaywer's theory Nasa didn't get thrust from a frustum without a dielectric - goes against Chinese and Shawyer's experimental results, goes against Shawyers theory.Shawyer has gotten different thrust directions from different set-ups (dielectric vs. none) - goes against theory, just outright strangeSo far, every experiment has used a drastically different apparatus, with different variable inputs and gotten massively different results. Thrust direction has not even remained constant. So when you look at the experiments in that light, the empirical data becomes rather sketchy. To date, as far as I know, no lab has truly replicated any other, and that's a problem.Edit: A problem that may be be solved by all the DIY yourself projects that are coming online this month. I may have to retire this criticism in a few weeks if strong data comes out of some of the replication attempts.
Shell
I believe there is enough empirical data in such widely varying test beds and that this is just enough out of the noise of chance that there is something going on and it deserves further testing.
http://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocityThe answer is phase velocityTherefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.
This guys think another wayhttp://arxiv.org/abs/0708.3519Quote from: WarpTech on 07/05/2015 01:09 am...This is where I'm at... The attached image is the derivation of the Photon Rocket equation, for an open-ended circular waveguide. So anyone who says a photon rocket can only exert a maximum force of F = 2P/c, is only correct in free space but not when confined to a waveguide. The thrust-to-power ratio is much, much larger near the cut-off.
...This is where I'm at... The attached image is the derivation of the Photon Rocket equation, for an open-ended circular waveguide. So anyone who says a photon rocket can only exert a maximum force of F = 2P/c, is only correct in free space but not when confined to a waveguide. The thrust-to-power ratio is much, much larger near the cut-off.
Quote from: deltaMass on 07/05/2015 03:58 amhttp://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocityThe answer is phase velocityTherefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocityInside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.Any text on waveguides will tell you the energy in the waveguide propogates down the waveguide at group velocity speed.
Quote from: TheTraveller on 07/05/2015 04:14 amQuote from: deltaMass on 07/05/2015 03:58 amhttp://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocityThe answer is phase velocityTherefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocityInside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.Any text on waveguides will tell you the energy in the waveguide propagates down the waveguide at group velocity speed.What you said is correct, if you are looking at energy. However, mass is different. If you want to convert from energy to mass;(dE/vgroup) = (dM*c2/vgroup) = (dM*vphase)So momentum depends on phase velocity. It makes a huge difference!Todd
Quote from: deltaMass on 07/05/2015 03:58 amhttp://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocityThe answer is phase velocityTherefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocityInside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.Any text on waveguides will tell you the energy in the waveguide propagates down the waveguide at group velocity speed.
.....I'm not sure that everybody has appreciated the fact that the Poyinting vector field shown in this message: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1399795#msg1399795 shows a very non-harmonic, asymmetric nonlinear time response cycle and its implications: .....
This guys think another wayhttp://arxiv.org/abs/0708.3519
The effective rest mass of guided photons inside a hollow waveguide, as the rest energy of photons inside the waveguide (i.e., the energy as the group velocity vg =0), arises by forming standing-waves along the transverse cross-section of the waveguide. In other words, it arises by freezing out the degree of freedom of transverse motion, or, by localizing and confining the electromagnetic energy along the 2D space perpendicular to the waveguide.
So forgive me that question. Is there a timeframe to expect results from the new test setup of NASA Eagleworks?
Degrasse Tyson sumed my work philosophy in Cosmos Unafraid of The Dark. "Question authority. No idea is true just because someone says so, including me. Think for yourself. Question yourself. Don't believe anything just because you want to. Believing something doesn't make it so. Test ideas by the evidence gained from observation and experiment. If a favorite idea fails a well-designed test, it's wrong! Get over it. Follow the evidence, wherever it leads. If you have no evidence, reserve judgment. And perhaps the most important rule of all Remember, you could be wrong. Even the best scientists have been wrong about some things. Newton, Einstein, and every other great scientist in history, they all made mistakes. Of course they did-- they were human."
Following discussions with Roger Shawyer, I now understand why using a scale to measure EMDrive Force generation is a waste of time.1) Basically when you sit the EMDrive on your scale based measurement system, it will be non moving. 2) Once you fill the frustum with microwaves it will be in IDLE mode waiting for some external Force to move/vibrate it slightly big end to small end. 3) Once that happens the EMDrive enters MOTOR mode and starts to build up an external Force. That Force will push against the measurement system and achieve a slight amount of room to slightly accelerate. 4) However soon after what ever compressive movement that was there is now gone, the EMDrive stops moving and flips back into IDLE mode and shutting off Force generation.The only way to allow the EMDrive to properly enter MOTOR mode and stay there needs the EMDrive to be free to move / accelerate.My test rig is now being redesigned into a rotary, totally enclosed, low air resistance and battery powered system that will allow continual acceleration for many minutes. A high resolution optical encoder will measure angular rotation to approx 1 part in 10,000 per revolution. On board will be a 8 channel data recorder which will accurately measure battery energy usage.The system will be able to resolve the apparent CofE paradox:1) Device continually accelerates obeying A = F/M2) KE increases at 1/2MV^2.The measurement of power supply energy consumed by the 20W RF amp as against KE will be done and compared.The tests will be streamed live. Data will be uploaded after the rotary test rigs stops spinning as there is not a laptop in the spinning test rig.My gut says I will see a constant energy usage by the 20W RF amp, constant acceleration and KE going up faster than the energy used by the 20W RF amp.I'm thinking about how to measure if the accumulated KE is real or just numbers on a piece of paper. Would need some form on a Pony Brake or something similar.Any suggestions most welcomeCrude drawing of rotary test rig attached.
Quote from: SeeShells on 07/04/2015 11:10 pmI'll be the first to admit there is something going on and it deserves further testing. I have never advocated, and never will, that testing should be abandoned. However, I have always been clear that I feel the likelihood that that something is propellantless thrust to be very low. Finding the exact quirk that gives the appearance of propellantless thrust is a worthwhile scientific endeavor in it's own right though.QuoteI believe there is enough empirical data in such widely varying test beds and that this is just enough out of the noise of chance that there is something going on and it deserves further testing.This right here is probably where you and I, and everyone else who has a different take on the emdrive from 100% likelihood to 0% likelihood, differ. When the emdrive first popped back into the news last august, I always heard the word replication being thrown around. Nasa has replicated a propellantless drive! It was replicated by the Chinese! UK inventor has drive replicated by Nasa and Chinese Labs! These were the kinds of headlines I saw. However, when you actually read through the individual papers, something practically explodes out at you. None of the experiments are actually replications of any of the others:The chinese got higher thrust from lower Q than Shawyer - goes against Shaywer's theory Nasa didn't get thrust from a frustum without a dielectric - goes against Chinese and Shawyer's experimental results, goes against Shawyers theory.Shawyer has gotten different thrust directions from different set-ups (dielectric vs. none) - goes against theory, just outright strangeSo far, every experiment has used a drastically different apparatus, with different variable inputs and gotten massively different results. Thrust direction has not even remained constant. So when you look at the experiments in that light, the empirical data becomes rather sketchy. To date, as far as I know, no lab has truly replicated any other, and that's a problem.Edit: A problem that may be be solved by all the DIY yourself projects that are coming online this month. I may have to retire this criticism in a few weeks if strong data comes out of some of the replication attempts.
Quote from: aceshigh on 06/22/2015 07:44 pmdid a search and did not find this... hope it was not posted yetQuoteAIAA Propulsion and Energy Forum and ExpositionHilton Orlando, Orlando, Florida...TUESDAY, JULY 28, 2015NFF-04. Future Flight Propulsion Systems...5:00 PM - 5:30 PMDirect Thrust Measurements of an EMDrive and Evaluation of Possible Side-EffectsMartin TajmarI wonder if someone from this thread could attend the conference and if there is a following Q/A, even mention some of the experiments discussed here, ask questions, etc.I am looking forward to this presentation. Unfortunately, I won't be attending. I have tried to find out, from several different second-hand sources what has been the nature of Martin Tajmar's experiments. It is my personal understanding that his EM Drive experiments have shown very low force/InputPower readings for an EM Drive in a partial vacuum: less than a few dozen or so times the force/InputPower of a perfectly collimated photon rocket, thus much lower thrust force/InputPower than Yang (who reported 300,000 times a photon rocket) and Shawyer (25,000 to 70,000 times) have reported. I understand that the quality factor of resonance (Q) in the experiments is extremely low, much lower than any researcher has reported up to now. Regarding possible questions to ask if anybody attends, one suggestion (if this is what is reported) is to ask why is his experimental Q so low (less than 100): how could the experiments have been conducted under resonance if the Q was so low?. Another question: what was responsible for such a low Q in the experiments, and whether Tajmar thinks that the discrepancy with other researchers has to do with the different Q reported from different researchers.
did a search and did not find this... hope it was not posted yetQuoteAIAA Propulsion and Energy Forum and ExpositionHilton Orlando, Orlando, Florida...TUESDAY, JULY 28, 2015NFF-04. Future Flight Propulsion Systems...5:00 PM - 5:30 PMDirect Thrust Measurements of an EMDrive and Evaluation of Possible Side-EffectsMartin TajmarI wonder if someone from this thread could attend the conference and if there is a following Q/A, even mention some of the experiments discussed here, ask questions, etc.
AIAA Propulsion and Energy Forum and ExpositionHilton Orlando, Orlando, Florida...TUESDAY, JULY 28, 2015NFF-04. Future Flight Propulsion Systems...5:00 PM - 5:30 PMDirect Thrust Measurements of an EMDrive and Evaluation of Possible Side-EffectsMartin Tajmar
Sorry, please explain to the Newtonian guy in me : how a play of throwing and bouncing and catching balls within a free floating box could give any persistent deltaV to the box ? deltaX I see, but not deltaV at the end of the story (when the game stops).