Quote from: frobnicat on 07/05/2015 12:24 amSorry, 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). Quite simply, you can't by any known method. You get nothing. I've tried it experimentally, and simple radiation pressure is bound by conservation of momentum. It doesn't work by simple bounces, period.The emDrive does not appear to work this way. You can't think of the light inside the cavity as individual photons, but instead consider the standing waves inside it. The really exciting bits from the last meep run the subsequent S vector calculations. As I see it, a portion of the standing waves "don't fit" the dimensions of the cavity and are being cut down to evanescent waves. The same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector. This is the unbalanced force that makes it go.Prediction: 1. We'll figure out a way to make this effect occur without a resonator.2. We'll prove Mach right, that there is a connection between inertia and gravity.2a. Conservation of momentum will get a loophole.2b. COM-violating actions that use this loophole will modify their inertia, creating a localized distortion in gravity.2c. General relativity and the GUT will both need a new equation to describe it.That will keep the Nobel prize committee busy for a decade
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).
Quote from: Rodal on 07/04/2015 06:00 pmQuote 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.Another suggested question to Prof. Tajmar: given the very low force/InputPower readings for an EM Drive in a partial vacuum measured by Prof. Tajmar (less than a few dozen or so times the force/InputPower of a perfectly collimated photon rocket), does Prof. Tajmar see his (and Georg Fiedler's) experiments at The Technische Universität Dresden as a scientific nullification of the claims made by Yang and Shawyer, since Yang and Shawyer claim over 1,000 to 10,000 times greater force/InputPower than what Tajmar measured) ?Does Prof. Tajmar think that the reason why Shawyer and Yang claimed much higher thrust is because Shawyer and Yang reported tests at ambient pressure (unlike Prof. Tajmar who has performed his tests in a vacuum), and Shawyer and Yang just reported thermal convection artifacts?If, not a nullification due to Shawyer and Yang not performing tests in vacuum, what does Prof. Tajmar think that the huge difference (1,000 to 10,000 times) is due to ?
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
If it works, then conservation of momentum does not hold, so Noether is wrong, so physics will have to be reformulated. Also, either thrust goes like F = k P, which implies that unlimited free energy is available from a perpetual motion machine of the first kind, or it goes like F = P/v, which implies that a preferred inertial reference frame exists, which violates a core principle of relativity and Einstein is wrong.Feeling lucky?
DERIVATION OF THRUST FROM A TAPERED WAVEGUIDE PHOTON ROCKETI updated the equations to make the derivation clearer. In these equations, z is the axis of the cone, theta is the half-angle, E is energy, M and m are mass terms, and the rest is just wave vectors in a waveguide.You can see that if the cone were not tapered there would be no dependence on z, the last term in the force equation would not exist. If it were not starting in a waveguide, the phase velocity would be c. Then we have a "flashlight" photon rocket. This is a different animal. This Force only applies when the big end is OPEN! Closed, all bets are off, but this explains where the tremendous thrust to power ratios are coming from.FYI: This is the foundation of the paper I'm writing. Now you have the "tech" right in front of you while I try to put this in "writing". Have at it! Can't wait to see what sort of designs you come up with. Todd
The same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector. This is the unbalanced force that makes it go.
Following discussions with Roger Shawyer, I now understand why using a scale to measure EMDrive Force generation is a waste of time.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.
Quote from: ElizabethGreene on 07/05/2015 02:02 pmThe same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector. This is the unbalanced force that makes it go.Maybe I misunderstand you, but I'm going to keep saying it for good measure: The Poynting vector, S, is NOT a force. Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces. An constant unbalanced force could only be generated if you saw that Poynting vector continuously and endlessly growing. This is the link to my previous comment on this issue.
New Baby EM Drive "results"https://hackaday.io/project/5596-em-drive/log/20473-preliminary-tests-swimming-platform
Quote from: wallofwolfstreet on 07/05/2015 03:47 pmQuote from: ElizabethGreene on 07/05/2015 02:02 pmThe same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector. This is the unbalanced force that makes it go.Maybe I misunderstand you, but I'm going to keep saying it for good measure: The Poynting vector, S, is NOT a force. Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces. An constant unbalanced force could only be generated if you saw that Poynting vector continuously and endlessly growing. This is the link to my previous comment on this issue. Correct, as a cursory glance at the units of the Poynting vector will show. It has units of power per unit area, whereby the area refers to the plane orthogonal to the direction of the power flux
..Maybe I misunderstand you, but I'm going to keep saying it for good measure: The Poynting vector, S, is NOT a force. Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces. An constant unbalanced force could only be generated if you saw that Poynting vector continuously and endlessly growing. ...
I'm an enemy of exposition. I feel there's no need to overstate.
Quote from: deltaMass on 07/05/2015 04:03 pmQuote from: wallofwolfstreet on 07/05/2015 03:47 pmQuote from: ElizabethGreene on 07/05/2015 02:02 pmThe same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector. This is the unbalanced force that makes it go.Maybe I misunderstand you, but I'm going to keep saying it for good measure: The Poynting vector, S, is NOT a force. Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces. An constant unbalanced force could only be generated if you saw that Poynting vector continuously and endlessly growing. This is the link to my previous comment on this issue. Correct, as a cursory glance at the units of the Poynting vector will show. It has units of power per unit area, whereby the area refers to the plane orthogonal to the direction of the power fluxIncorrect, another over-statement, http://forum.nasaspaceflight.com/index.php?topic=37642.msg1399888#msg1399888 as it is elementary knowledge that the time-averaged (over an integer number of periods) of the Poynting vector divided by the speed of light in free space is the radiation pressure exerted by an electromagnetic wave on the surface of a target, if the wave is completely absorbed by the target .Stress = <Poynting vector averaged over integer number of periods> / cthis formula has been verified experimentally multiple times since 1900 when the wave is absorbed by the targetPoynting vector = Power Surface Density = Power/area = Force*Velocity/areaStress= Force/Area = (Power/area)/CharacteristicVelocity =(Powery/area)/SpeedOfLightAs photons travel at the speed of light
....Incorrect if you are disputing the units of the Poynting vector as I described them. Are you?
Quote from: deltaMass on 07/05/2015 04:13 pm....Incorrect if you are disputing the units of the Poynting vector as I described them. Are you?For non-elementary problems in Physics the fundamental quantity to derive forces is the stress. The equations of equilibrium for non-uniform stress are formulated in terms of stress and not forces.
Maybe I misunderstand you, but I'm going to keep saying it for good measure: The Poynting vector, S, is NOT a force.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1040027Quote from: WarpTech on 07/05/2015 06:18 amDERIVATION OF THRUST FROM A TAPERED WAVEGUIDE PHOTON ROCKETI updated the equations to make the derivation clearer. In these equations, z is the axis of the cone, theta is the half-angle, E is energy, M and m are mass terms, and the rest is just wave vectors in a waveguide.You can see that if the cone were not tapered there would be no dependence on z, the last term in the force equation would not exist. If it were not starting in a waveguide, the phase velocity would be c. Then we have a "flashlight" photon rocket. This is a different animal. This Force only applies when the big end is OPEN! Closed, all bets are off, but this explains where the tremendous thrust to power ratios are coming from.FYI: This is the foundation of the paper I'm writing. Now you have the "tech" right in front of you while I try to put this in "writing". Have at it! Can't wait to see what sort of designs you come up with. ToddWhere the first equation comes from, and what is "Xmn"