Quote from: zaphod_vi on 05/24/2015 03:12 pmQuoteNote: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration. The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.Since the year 1900 by Lebedev (see: http://web.ihep.su/dbserv/compas/src/lebedev01/eng.pdf ), experiments have been conducted, confirming that Maxwell was correct that the radiation pressure of photons against a surface push the surface in the same direction as the force , such that positive work is performed. This (Maxwell's theory and the experiments that have verified it) is in sharp contrast with Shawyer's theory claiming that the Thrust pressure of photons towards the Big Diameter results in motion of the EM Drive in the opposite direction, towards the Small Diameter . (This results, as I have shown, in the curious behavior that the Work being done is negative, according to Shawyer's theory)
QuoteNote: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration. The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.
Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration. The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.
Quote from: deltaMass on 05/24/2015 06:42 pm...When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration. what matters is what she means: her words: "net EM ... directs towards the minor end plate". The microwave EM is inside not outside, hence no ambiguity
...When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration.
Quote from: deltaMass on 05/24/2015 08:06 pmThis discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.Let's cut the Gordian Knot!The test program I plan to run will remove ALL doubt that the EMDrive generates real propellantless thrust without needing a space test. One of my goals is to be able to hold the EMDrive & while switching it on and off, to be able to FEEL the thrust.
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.Let's cut the Gordian Knot!
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.No new physics?
...What she means by "Thrust" is very clear. It is the sum off all the electric and magnetic forces acting the surfaces of the frustum. What Shawyer refers to as thrust is ambiguous, since he says the side walls have no contribution to the forces.Her use of complex fields incorporates the attenuation factors. With her equations, 12 thru 14, and the graphs in Zeng and Fan, predictions can be extrapolated based on theta. I said I had a lot of reading to do. I wish I had read this one a week ago. On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.Thanks!Todd
Mode TM011 thrusters has the worst performance
Quote from: TheTraveller on 05/24/2015 07:48 pm...That is not new news. Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.Well,let's forget that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using waveguide modes like TM01, cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer. But let's forget about that. How do you know that "both approaches is the same level of measured versus predicted thrust." ?Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?
...That is not new news. Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Quote from: deltaMass on 05/24/2015 07:26 pmIf Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.No new physics?I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.Todd
Quote from: Rodal on 05/24/2015 07:53 pmQuote from: TheTraveller on 05/24/2015 07:48 pm...That is not new news. Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.Well,let's forget that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using waveguide modes like TM01, cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer. But let's forget about that. How do you know that "both approaches is the same level of measured versus predicted thrust." ?Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?Did you already ask her directly? [email protected]I found her email in her published papers and on her profile page on the Northwestern Polytechnical University web site.
Quote from: WarpTech on 05/24/2015 08:25 pm...On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.Notice that Prof. Yang writes Section 3.2 page 9 of the translated paper http://www.emdrive.com/NWPU2010translation.pdf :Quote from: Yang Mode TM011 thrusters has the worst performance this is diametrically opposite to Shawyer's reported aim at TM01(Recall that TM010 is an impossible mode for truncated cones because p=0 stands for constant electromagnetic field in the longitudinal direction which is impossible for a truncated cone. Hence it is not immediately clear to me what degenerate mode of TM011 she is referring to as there are two degenerate TM011 modes in a truncated cone near each other)
...On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.
Yang doesn't take the free dynamics bull by the horns.Also, if she's using heat dissipation as an explanation, how does this system manage not to be a photon rocket?
Quote from: WarpTech on 05/24/2015 08:49 pmQuote from: deltaMass on 05/24/2015 07:26 pmIf Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.No new physics?I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.ToddIt also appears that Prof. Yang solves the CoM puzzle by taking into account dissipation losses, which involves the 2nd law of thermodynamics and hence entropy.Entropy gives a preferred direction (causality).
1) Yang has the thrust force (from the EM field) directed towards the Small End. This is completely opposite to Shawyer's unorthodox "thrust force".
Quote from: deltaMass on 05/24/2015 09:14 pmYang doesn't take the free dynamics bull by the horns.Also, if she's using heat dissipation as an explanation, how does this system manage not to be a photon rocket?(...)No idea how she can get Force/InputPower thousands of times better than perfect photon rocket.(...)