Quote from: deltaMass on 05/19/2015 09:29 amQuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.Mike
QuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
Quote from: Mike-F on 05/19/2015 02:18 pmQuote from: deltaMass on 05/19/2015 09:29 amQuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.MikeEarth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.
Quote from: txdrive on 05/19/2015 02:02 pmUltimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.Where is Shawyer wrong?1) Is the cutoff wavelength different at the small and big ends or not?2) Is the guide wavelength different at the small and big ends or not?3) Is the group velocity different at the small and big ends or not?4) Is the bounce force different at the small and big ends or not?5) Is the bounce force at the big end greater than at the small end or not?6) Is there a bounce force on the side walls or not?Just trying to understand where you believe Shawyer is wrong?
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.
Quote from: TheTraveller on 05/19/2015 02:32 pmQuote from: txdrive on 05/19/2015 02:02 pmUltimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.Where is Shawyer wrong?1) Is the cutoff wavelength different at the small and big ends or not?2) Is the guide wavelength different at the small and big ends or not?3) Is the group velocity different at the small and big ends or not?4) Is the bounce force different at the small and big ends or not?5) Is the bounce force at the big end greater than at the small end or not?6) Is there a bounce force on the side walls or not?Just trying to understand where you believe Shawyer is wrong?Well, firstly, Shawyer has greater radiation pressure upon the wide end, but his drive is pushing narrow end forwards. Secondarily, yes, there is an interaction between the EM field and the walls, which results in a force on the side walls, equal to change in momentum of the EM field travelling down it, per time.
The number of photons (N) inside a cavity is not conserved. A photon may collide with an electron on a wall, exciting it to a higher energy state, removing a photon. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the cavity. Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary. The absorption (emission) of one photon might be accompanied by the emission (absorption) of more than one photon, as long as the frequency of the photons involved are such that the energy of the system remains constant.N over volume, and the entropy density are proportional to the cube of the temperature of the photon gas, while the pressure and the energy density are proportional to the fourth power of its temperature. For black body radiation it can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero.How does the Entropy/Information Bound Work? http://arxiv.org/pdf/quant-ph/0404042
Ah, found it. Dr. Rodal please note well the highlighted section in the 2nd attachment.Here is how Shawyer measured his 2 force measurements on his Demonstrator EM Drive as per the 4th results line of the 1st attachment.He used the rotary test rig and measured the acceleration and deceleration forces generated by the EM Drive. Did this in both directions. IE CW acceleration, then CW deceleration, then CCW acceleration, then CCW deceleration. Clever boy our Roger.
Thank you for the information.My question was how were the two forces (what Shawyer calls "reaction" and "thrust") measured simultaneously (I had labored to use Italics first and then bold and blue to highlight "simultaneously").From the description provided it looks like there has been no experiment measuring simultaneously the two forces (what Shawyer calls "reaction" and "thrust") that (quoting you) "Clever boy our Roger" claims to have measured.All that is being measured is displacement vs. time (or its second-order derivative with respect to time, whatever its sign) of the deviceThe problem with making measurements in acceleration and deceleration and then ascribing the results to the two forces are evident.
...there is an interaction between the EM field and the walls, which results in a force on the side walls, equal to change in momentum of the EM field travelling down it, per time.
I was wondering if we would be able to get a faster turnaround with prototyping and maybe even cut costs if we could use 3D printing and e.g. conductive graphene filament like this one:We could share computer designs and use local 3D printing services. Would that work?
Quote from: txdrive on 05/19/2015 02:35 pmQuote from: Mike-F on 05/19/2015 02:18 pmQuote from: deltaMass on 05/19/2015 09:29 amQuoteFrustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the very small forces developed so far.MikeEarth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.Frustum would need to constantly accelerate to be able to see resonant frequency changes.
Hello. I've been reading this thread and Iulian's blog with great interest. I'm just wondering if all of the calculations on possible thrust have only been done on truncated cones or cylinders... after Mr. Iulian retries his experiment inverting the frustrum to see if it's a metal hot air balloon, I'm curious what would happen if...one used a conical bore similar to the bell of a brass musical instrument. As an experiment, has anyone tried these experiments using a shape similar to the bell end of a tuba, sousaphone, french horn, etc? It would probably be pretty easy to try this experiment using a shape similar to this... maybe with a different material? If this has been addressed (or if a dumb question) I'll remove my post...thanks!
Quote from: TheTraveller on 05/19/2015 02:32 pmQuote from: txdrive on 05/19/2015 02:02 pmUltimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.Where is Shawyer wrong?1) Is the cutoff wavelength different at the small and big ends or not?2) Is the guide wavelength different at the small and big ends or not?3) Is the group velocity different at the small and big ends or not?4) Is the bounce force different at the small and big ends or not?5) Is the bounce force at the big end greater than at the small end or not?6) Is there a bounce force on the side walls or not?Just trying to understand where you believe Shawyer is wrong?1-2-3) It really doesn't make sense to talk about "group velocity", "cutoff wavelength" for different "ends" in this case. A cavity is not a waveguide. Introducing end plates (whether curved or flat) changes the boundary conditions and thus the mode structure of the EM fields. There is just one cutoff wavelength for the entire cavity, much like an organ pipe has one "fundamental" tone. Please understand that Egan's calculation of the fields is an exact solution of Maxwell's equations. Shawyer's talk about waveguides is at best a sloppy approximation. 4-5-6) There are forces on all surfaces of the cavity. Again referring to Egan's website, in the standard formulation of Maxwell's equations, for any closed cavity supporting time-harmonic fields, the integral of forces on the walls vanishes. To suggest Maxwell's equations say otherwise is just bad physics.Generically, a question I asked many many pages ago, and that everyone has danced around: if the EM drive works, we must have a non-classical coupling of electromagnetic fields to something else. Why has this coupling never been observed before? What is special about a copper cone?
Quote from: Rodal on 05/19/2015 02:18 pmThe number of photons (N) inside a cavity is not conserved. A photon may collide with an electron on a wall, exciting it to a higher energy state, removing a photon. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the cavity. Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary. The absorption (emission) of one photon might be accompanied by the emission (absorption) of more than one photon, as long as the frequency of the photons involved are such that the energy of the system remains constant.N over volume, and the entropy density are proportional to the cube of the temperature of the photon gas, while the pressure and the energy density are proportional to the fourth power of its temperature. For black body radiation it can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero.How does the Entropy/Information Bound Work? http://arxiv.org/pdf/quant-ph/0404042One point to keep in mind is that the change from 2GHz to ambient thermal radiation is an up-conversion, that is, it represents a negative entropy change component that must be more than made up somewhere else.
As an example we consider the Casimir effect with different temperatures between the plates (T) resp. outside of them (T′). For T′ < T the pressure of heat radiation can eventually compensate the Casimir force and the total pressure can vanish...If both T and T′ are fixed (isothermal case), this equilibrium has turned out unstable.