Quote from: Rodal on 05/06/2015 07:45 pmQuote from: SeeShells on 05/06/2015 07:44 pmI may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Yes, see this analysis by one of the people in this forum:https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECTThat's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?
Quote from: SeeShells on 05/06/2015 07:44 pmI may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Yes, see this analysis by one of the people in this forum:https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT
I may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.
Rodal: " Their results could be due to outgassing from FRP4"This is some sort of fibreglass?
Quote from: deltaMass on 05/06/2015 09:05 pmQuote from: Rodal on 05/06/2015 07:45 pmQuote from: SeeShells on 05/06/2015 07:44 pmI may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Yes, see this analysis by one of the people in this forum:https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECTThat's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?Thermal buckling is extremely dependent on initial imperfections, thus it is highly unlikely that it can be the only explanation for multiple tests at multiple locations with multiple specimens.Therefore something else is at play here.Pressure measurements due to radiation have been plagued with air convection currents for 140 years.None of the experimenters have used the proper test set-up in ambient conditions: nobody has used concentric rings (see this http://forum.nasaspaceflight.com/index.php?topic=36313.msg1370479#msg1370479 )Only NASA Eagleworks is the only one that has conducted tests in a vacuum. Their results could be due to outgassing from the fiberglass-reinforced-epoxy end-plate.Therefore I highly advise that they should replace the end plates with concentric rings to rule out false positives, as done by Cullen in 1951, the first person to accurately measure microwave radiation pressure from microwaves.
Quote from: PaulF on 05/06/2015 04:35 pmQuestion to all:Has quantum tunneling been incorporated in any calculations? I read once that at least some photons will tunnel through the medium of the cavity walls. Hope this sparks something in someone's mind.Yes, we considered it. It would become an inefficient photon rocket, as only a few of the photons would tunnel and the beam would not be perfectly collimated. Hence it would not explain a claimed thrust/PoweInput thousands of times greater than a perfectly collimated photon rocket.
Question to all:Has quantum tunneling been incorporated in any calculations? I read once that at least some photons will tunnel through the medium of the cavity walls. Hope this sparks something in someone's mind.
Quote from: deltaMass on 05/06/2015 09:05 pmQuote from: Rodal on 05/06/2015 07:45 pmQuote from: SeeShells on 05/06/2015 07:44 pmI may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Yes, see this analysis by one of the people in this forum:https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECTThat's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?I'm slowly digging through the nice thermal expansion write-up, nice work. I was wondering if you have an IR camera and pics to back your calculations, as I'd like to see the thermal increases not only on the endcap but on the sides of the EM chamber. Thanks Guys!
Quote from: WarpTech on 05/06/2015 09:05 pmRegarding the energy paradox.Power = Force * VelocityAcceleration = Force / Mass = Power / MomentumTherefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something. Best Regards,Todd D.No. You are conflating input power and output power here. Please see my analysis.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875The EmDrive is not a tyre and spacetime is not the road upon which it rides.If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.
Regarding the energy paradox.Power = Force * VelocityAcceleration = Force / Mass = Power / MomentumTherefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something. Best Regards,Todd D.
No. You are conflating input power and output power here. Please see my analysis.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875The EmDrive is not a tyre and spacetime is not the road upon which it rides.If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.
Special Relativity does not apply to accelerating reference frames, which is what is being described here. Accelerated reference frames "are" preferred frames because they can be distinguished from one another, unlike inertial frames.If F = P*k
Then the work done is the integral;W = integral[Pin*k*v]*dt from t=0 to t2.Pout = dW/dt = Pin*k*vSince Pin = Pout, k = 1/v
The Power in will equal the Power out, the Work done will be the integration of Force * distance. Acceleration is not constant with constant Power input. I have a hunch that there is a hidden assumption in your derivation that acceleration is constant, so you get over-unity results.
This needs to be considered like a Power Transformer. Power in = Power out.That's my 2 cents worth.Todd D.
Quote from: deltaMass on 05/06/2015 09:10 pmQuote from: WarpTech on 05/06/2015 09:05 pmRegarding the energy paradox.Power = Force * VelocityAcceleration = Force / Mass = Power / MomentumTherefore, as the momentum increases, the acceleration decreases for a constant power input. That's without relativistic effects. Why is this a paradox? You've mentioned this a few times, but I guess I've missed something. Best Regards,Todd D.No. You are conflating input power and output power here. Please see my analysis.http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875The EmDrive is not a tyre and spacetime is not the road upon which it rides.If you propose that an EmDrive accelerating in free space exhibits thrust which depends somehow on its velocity, then what you propose violates special relativity.Special Relativity does not apply to accelerating reference frames, which is what is being described here. Accelerated reference frames "are" preferred frames because they can be distinguished from one another, unlike inertial frames.If F = P*kThen the work done is the integral;W = integral[Pin*k*v]*dt from t=0 to t2.Pout = dW/dt = Pin*k*v, Since Pin = Pout, k = 1/v.The Power in will equal the Power out, the Work done will be the integration of Force * distance. Acceleration is not constant with constant Power input. I have a hunch that there is a hidden assumption in your derivation that acceleration is constant, so you get over-unity results. This needs to be considered like a Power Transformer. Power in = Power out.That's my 2 cents worth.Todd D.
Quote from: SeeShells on 05/06/2015 09:44 pmQuote from: deltaMass on 05/06/2015 09:05 pmQuote from: Rodal on 05/06/2015 07:45 pmQuote from: SeeShells on 05/06/2015 07:44 pmI may be just an engineer but over the 40 years of my career I've plenty of unexplained things in designs. Anyone taken into consideration the thermal expansion coefficient of the EM case during your pulsed phase? I've been reading for days and there is so much material I might have missed it. Sorry if I did.Yes, see this analysis by one of the people in this forum:https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECTThat's an excellent analysis - Kudos. I would not be surprised if you were a small numerical factor in error (as I'm sure neither would you be) and as such you're pointing up the possibility of all the measured thrust being attributable to thermally-induced movement.And of course, the measurement of a reverse thrust does not gainsay the thermal explanation, since everything will be thermally perturbed in the opposite direction when the cavity is mounted 180o to its default mounting orientation.Mr. March counters this with the fact that the measured thrust onset is as prompt as that of the calibration pulse. Yet you are showing quite prompt thermal onsets. How do you reconcile these two points of view?I'm slowly digging through the nice thermal expansion write-up, nice work. I was wondering if you have an IR camera and pics to back your calculations, as I'd like to see the thermal increases not only on the endcap but on the sides of the EM chamber. Thanks Guys!These are the thermal measurements vs. thermal and electromagnetic field analysis (COMSOL FEA) for NASA Eagleworks for the experiments in a partial vacuum :http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634723The thermal distribution is clearly due to induction heating from the magnetic field, as expected.My exact solution (elsewhere in other posts) for the magnetic field, for the electric field, confirms that the numerical solution using COMSOL FEA is within 1% of the exact solution, they used a good finite element mesh discretization and the numerical solution is practically converged to the exact result.Also Prof. Juan Yang's reported temperature vs. time measurements with embedded thermocouples throughout their EM Drive cavity (without a polymer dielectric insert) under atmospheric conditions, that, curiously, show the highest temperature at the center of the small base (trace #1), followed, at a significantly lower temperature by the temperature at the periphery of the big base (trace #5). Notice how much higher temperature is present in the Chinese (Yang) experiments.Shawyer has not reported graphical information on thermal measurements for his experiments, to my knowledge.I suspect same problem for Shawyer's experiments: huge thermal effects for Yang and Shawyer.Also, tan delta out-of-phase losses in these cavities are not zero,particularly in NASA's dielectric polymer insert: the reported experiments show that the tan delta values of the materials used in these cavities is consistent with real materials experiencing out-of-phase dissipation (therefore one must use the complex form of the physical properties and not neglect the imaginary part if one is interested in assessing the finite value of Q, for example).
....Thank You for taking your time to answer me! I've got a little to digest here, but there is more than enough. Is there any reason no one has used a simple copper mesh for the EM chamber?
It's good that at least one person understands what I'm on about. Consider an EmDrive in free space and accelerating. We switch it off temporarily and let it coast at speed v relative to the inertial frame in which it began its acceleration. When we switch it back on, are we going to assert that somehow the thrust F knows what speed it's going and adjusts the thrust like F = P/v?I assert again that this kind of thinking requires a preferred frame, and thus violates SR.
This condition occurs at a change in time of which equates to a. When thissituation occurs, in order to ensure that the input energy isequal to the change in kinetic energy, the thrust to powerperformance will have to decrease over time. This scenariohas an analog in the terrestrial realm when consideringa turbine aircraft flight profile. At takeoff, the turbineaircraft has a very high thrust to power (hundreds ofN/kW), but at cruise altitude, the thrust to power performanceis much lower (1-10 N/kW). The following graphshows the curve with some highlighted data points forconsideration.