@Rodal or anyone for that matter know how to calculate shawyer's design factor?In the conclusion Tajmar also said that the thrust measured in the oil damped torsion balance was close to the original predicted thrust if they take into consideration the smaller Q (the value they analyzed and calculated at the end of the oil damped torsion test). Since he states the original prediction of 98.2 micro newtons as if it was calculated using the output power of the magnetron via Shawyer's model. I would like to believe that his statement in the conclusion means they re ran the calculation for the prediction with the new Q value.
Quote from: deltaMass on 07/25/2015 11:21 pmQuote from: WarpTech on 07/25/2015 10:40 pmThis graph clearly shows that the group velocity for small kr is faster than light.Seriously?I am interpreting what I see. If you or anyone else has a different interpretation of it, by all means let's discuss it. This is important, because this is where the breakthrough in "new physics" is going to be found. Impedance is what it is, permeability x velocity. Normalized, these plots represent relative velocity, relative impedance or relative refractive index as a function of kr and cone angle. Take your pick. Hmm... getting over that peak in the phase velocity sort of reminds me of jumping to warp, doesn't it? ToddEDIT: The peak in the TE11 graph occurs at the same kr, where the light barrier is broken in the TM01 graph. It is precisely where the ingoing wave becomes evanescent.
Quote from: WarpTech on 07/25/2015 10:40 pmThis graph clearly shows that the group velocity for small kr is faster than light.Seriously?
This graph clearly shows that the group velocity for small kr is faster than light.
http://jpkc.fudan.edu.cn/picture/article/90/64657339-a919-423f-b5ff-425cd2983d2d/3f750fa7-9772-40c4-802b-2a27834d20e9.pdfJust popping in after months of lurking; this seems appropriate for context to the above post. Still behind on the math, but getting there...edit: also still unsure if this is a huge conspiracy by Tajmar, Woodward, DeltaMass, Rodal, Shawyer, et al. but i'm giving it a chance.
@Rodal or anyone for that matter know how to calculate shawyer's design factor?
So assuming the Shawyer model Tajmar is referring to is Equation 1 in www.emdrive.com/Brighton2005paper.doc
Quote from: birchoff on 07/26/2015 02:12 am@Rodal or anyone for that matter know how to calculate shawyer's design factor?Shawyer's Df equation is attached. Have verified with Shawyer that it is correct.
Quote from: Prunesquallor on 07/25/2015 01:32 pmQuote from: Rodal on 07/25/2015 12:07 pmit can only be seen as disappointing, as the numbers obtained by Tajmar a couple of months ago are so much lower than reported by Yang and Shawyer and even much lower (when taking into account the InputPower) than obtained by NASA.Who thinks that one can get to Pluto in 18 months with something that only gives 50 microNewton for hundreds of watts inputPower Vacuum. I look at this quite differently. If ANY verifiable, repeatable, non-experimental-artifact thrust significantly exceeding photon rocket level is demonstrated, it is mind-blowing. I seriously doubt that the experiments being performed today would have stumbled upon the optimal combination of design parameters that maximize performance. Getting the general principles accepted and understood is step one. THEN the engineers can go wild and see what the potential really is. Having goals for that performance (e.g. space applications) is, I think useful even if the lab results are not there yet. I agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.Still, I await the numbers and verification at other labs before I believe it. However, I am more optimistic that another test in vacuum shows some thrust.Quote from: Prunesquallor on 07/25/2015 01:32 pmThe Wright brothers demonstrated that the combination of the tecnology of the internal combustion engine and the science of aerodynamics could result in a heavier-than-air machine with lift/weight>1. Many experts had declared that impossible. One could argue that the P-51 or the B-29 were straightforward engineering enhancements of those basic principles.With more hard work we went from the P-51 to the SR-71. Maybe one day the EM drive will live up to the hype.
Quote from: Rodal on 07/25/2015 12:07 pmit can only be seen as disappointing, as the numbers obtained by Tajmar a couple of months ago are so much lower than reported by Yang and Shawyer and even much lower (when taking into account the InputPower) than obtained by NASA.Who thinks that one can get to Pluto in 18 months with something that only gives 50 microNewton for hundreds of watts inputPower Vacuum. I look at this quite differently. If ANY verifiable, repeatable, non-experimental-artifact thrust significantly exceeding photon rocket level is demonstrated, it is mind-blowing. I seriously doubt that the experiments being performed today would have stumbled upon the optimal combination of design parameters that maximize performance. Getting the general principles accepted and understood is step one. THEN the engineers can go wild and see what the potential really is. Having goals for that performance (e.g. space applications) is, I think useful even if the lab results are not there yet.
it can only be seen as disappointing, as the numbers obtained by Tajmar a couple of months ago are so much lower than reported by Yang and Shawyer and even much lower (when taking into account the InputPower) than obtained by NASA.Who thinks that one can get to Pluto in 18 months with something that only gives 50 microNewton for hundreds of watts inputPower Vacuum.
The Wright brothers demonstrated that the combination of the tecnology of the internal combustion engine and the science of aerodynamics could result in a heavier-than-air machine with lift/weight>1. Many experts had declared that impossible. One could argue that the P-51 or the B-29 were straightforward engineering enhancements of those basic principles.
Tajmar et.al.'s observation on the knife-edge balance that may be useful to rfmwgy and SeeShell's experiments:Quote from: M. Tajmar and G. Fiedler...The difference between upwards and downwards measurements was 229 μN and therefore close to our expectation of 2x98 μN. The horizontal direction was supposed to be our zero thrust reference, and indeed it was about only 1/3 of the downwards measure...observations are as follows: The balance configuration seems to indeed measure thrust in the correct direction and magnitude as claimed byShawyer. The horizontal direction was supposed to measure only thermal effects and no thrust. We observed a turn-oneffect (of the same magnitude compared to other thrust directions but with an opposite value) and then anincrease to about 100 μN until the power was turned off. We then saw a behavior that was indeed expected froma thermal side-effect: The thrust still further increased a bit (delay from thermal shielding) and then went downto zero. The thruster up/down direction showed a very different behavior. They increased to 620 μN and 391 μNrespectively and then remained constant for a much larger time compared to the horizontal direction. A differentorientation of the magnetron (horizontal versus vertical) may have caused different thermal signatures andtherefore buoyancy effects. Still, this behavior was really different and repeatable. In the much lower powermeasurements from Brady et al on the torsion balance, we can also see that it took some time after power turnoff that the balance reading went back to zero as if the EMDrive got somehow charged and produced thrust which rather decays contrary to a simple switch off after power is removed.Our weakest part in this setup was certainly the simple connection of the magnetron with three flexible siliconisolated wires to the power supply. A current of several Ampere is flowing over those wires which can generatesignificant magnetic forces (although we tried to keep the wires close together such that the magnetic effects cancel) that may have influenced our measurements. This together with the buoyancy effect made this measurement setup less convincing compared to a torsion balance setup.The buoyancy observations match the buoyancy observations of Iulian Berca.
...The difference between upwards and downwards measurements was 229 μN and therefore close to our expectation of 2x98 μN. The horizontal direction was supposed to be our zero thrust reference, and indeed it was about only 1/3 of the downwards measure...observations are as follows: The balance configuration seems to indeed measure thrust in the correct direction and magnitude as claimed byShawyer. The horizontal direction was supposed to measure only thermal effects and no thrust. We observed a turn-oneffect (of the same magnitude compared to other thrust directions but with an opposite value) and then anincrease to about 100 μN until the power was turned off. We then saw a behavior that was indeed expected froma thermal side-effect: The thrust still further increased a bit (delay from thermal shielding) and then went downto zero. The thruster up/down direction showed a very different behavior. They increased to 620 μN and 391 μNrespectively and then remained constant for a much larger time compared to the horizontal direction. A differentorientation of the magnetron (horizontal versus vertical) may have caused different thermal signatures andtherefore buoyancy effects. Still, this behavior was really different and repeatable. In the much lower powermeasurements from Brady et al on the torsion balance, we can also see that it took some time after power turnoff that the balance reading went back to zero as if the EMDrive got somehow charged and produced thrust which rather decays contrary to a simple switch off after power is removed.Our weakest part in this setup was certainly the simple connection of the magnetron with three flexible siliconisolated wires to the power supply. A current of several Ampere is flowing over those wires which can generatesignificant magnetic forces (although we tried to keep the wires close together such that the magnetic effects cancel) that may have influenced our measurements. This together with the buoyancy effect made this measurement setup less convincing compared to a torsion balance setup.
Quote from: Rodal on 07/26/2015 01:11 amQuote from: deltaMass on 07/25/2015 10:37 pmWith such small thrust and the apparatus not being self-contained, I am wary to break out any champagne here.Tajmar concludes:Quote from: Tajmar and FiedlerThe nature of the thrusts observed is still unclear. Additional tests need to be carried out to study the magnetic interaction of the power feeding lines used for the liquid metal contacts. Our test campaign can not confirm or refute the claims of the EMDrive but intends to independently assess possible side-effects in the measurements methods used so far This is the most lukewarm kind of support imaginable. Shawyer is encouraged by this ? ( http://www.wired.co.uk/news/archive/2015-07/24/emdrive-space-drive-pluto-mission )Quote from: Wired article The 'impossible' EmDrive could reach Pluto in 18 months Roger Shawyer is encouraged by Tajmar's work, which he says validates his own theoretical predictions as well as his experimental results. The authors state that they can not confirm or refute the claims of the EMDrive !!!!!(page 9 of Tajmar's report)If the authors themselves conclude that they cannot confirm or deny the EM Drive claims, there is nothing here for John Baez or Sean Carroll to have to respond to. All that Baez and Carroll have to do is to quote the authors saying that the authors accept that their report is inconclusive !Considering the fact that tajmar was not able to completely refute his claims. I can see how Shawyer would be encoraged. Think about it this way. Since he went public with his claims most everyone in the scientific community as labelled him a crack pot selling snake oil, or an idiot that doesnt know how to run an experiment. I believe in an earlier segment of this thread a comment was made about not trying hard enough to find your own errors. The fact that his experiment has received this much scrutiny from a NASA lab and now Tajmar's lab and the possibility that this is actually useful thrust has not been completely taken off the table. If I were him I would be encouraged too. Sure this wont win over the hard skeptics, But I think their is pretty much no room left for skeptics claiming that the reason this signal is still being seen is because of something trivial.
Quote from: deltaMass on 07/25/2015 10:37 pmWith such small thrust and the apparatus not being self-contained, I am wary to break out any champagne here.Tajmar concludes:Quote from: Tajmar and FiedlerThe nature of the thrusts observed is still unclear. Additional tests need to be carried out to study the magnetic interaction of the power feeding lines used for the liquid metal contacts. Our test campaign can not confirm or refute the claims of the EMDrive but intends to independently assess possible side-effects in the measurements methods used so far This is the most lukewarm kind of support imaginable. Shawyer is encouraged by this ? ( http://www.wired.co.uk/news/archive/2015-07/24/emdrive-space-drive-pluto-mission )Quote from: Wired article The 'impossible' EmDrive could reach Pluto in 18 months Roger Shawyer is encouraged by Tajmar's work, which he says validates his own theoretical predictions as well as his experimental results. The authors state that they can not confirm or refute the claims of the EMDrive !!!!!(page 9 of Tajmar's report)If the authors themselves conclude that they cannot confirm or deny the EM Drive claims, there is nothing here for John Baez or Sean Carroll to have to respond to. All that Baez and Carroll have to do is to quote the authors saying that the authors accept that their report is inconclusive !
With such small thrust and the apparatus not being self-contained, I am wary to break out any champagne here.
The nature of the thrusts observed is still unclear. Additional tests need to be carried out to study the magnetic interaction of the power feeding lines used for the liquid metal contacts. Our test campaign can not confirm or refute the claims of the EMDrive but intends to independently assess possible side-effects in the measurements methods used so far
Roger Shawyer is encouraged by Tajmar's work, which he says validates his own theoretical predictions as well as his experimental results.
This are the lowest natural frequencies I calculate for those dimensions:4.376 GHz "TE111 Cyl" Q=56,599
I know there is plenty that could be said negatively about him for good reason. But sometimes it seems his critics feel unable or unwilling to give him even the slightest sliver of positive response. I suspect that this will be another of those occasions which will end with more negativity going in his direction.
A number of methods have been used in the UK, the US and China to measure theforces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on anincreasing or decreasing background force, generated by the test equipment itself.Indeed, in the UK when the background force changes were eliminated, in an effortto improve force measurement resolution, no EmDrive force was measured. Thiswas clearly a result of attempting to measure the forces on a fully static thruster,where T and R cancel each other.UK flight thruster measurements employ this principle to calibrate the backgroundnoise on the force balance prior to carrying out force measurements.
Quote from: Star One on 07/26/2015 08:44 amI know there is plenty that could be said negatively about him for good reason. But sometimes it seems his critics feel unable or unwilling to give him even the slightest sliver of positive response. I suspect that this will be another of those occasions which will end with more negativity going in his direction.Suspect too many physicists and mathematicians have dug too deep a hole for themselves to ever admit they were mistaken about Shawyer.When I get my rotary test rig up and spinning, will watch how many have the guts to admit they were wrong. And to answer the big question: Why is the vacuum Force generated less than in air? Explained here:http://www.emdrive.com/EmDriveForceMeasurement.pdfQuoteA number of methods have been used in the UK, the US and China to measure theforces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on anincreasing or decreasing background force, generated by the test equipment itself.Indeed, in the UK when the background force changes were eliminated, in an effortto improve force measurement resolution, no EmDrive force was measured. Thiswas clearly a result of attempting to measure the forces on a fully static thruster,where T and R cancel each other.UK flight thruster measurements employ this principle to calibrate the backgroundnoise on the force balance prior to carrying out force measurements.What major external force is available in air that is not available in vacuum? Air vibrations which will generate a bigger Big to Small force than Small to Big force. Perfect for moving an EMDrive from IDLE mode into MOTOR mode when being tested in atmo but no help at all when testing in vacuum.
Quote from: TheTraveller on 07/26/2015 09:00 amQuote from: Star One on 07/26/2015 08:44 amI know there is plenty that could be said negatively about him for good reason. But sometimes it seems his critics feel unable or unwilling to give him even the slightest sliver of positive response. I suspect that this will be another of those occasions which will end with more negativity going in his direction.Suspect too many physicists and mathematicians have dug too deep a hole for themselves to ever admit they were mistaken about Shawyer.When I get my rotary test rig up and spinning, will watch how many have the guts to admit they were wrong. And to answer the big question: Why is the vacuum Force generated less than in air? Explained here:http://www.emdrive.com/EmDriveForceMeasurement.pdfQuoteA number of methods have been used in the UK, the US and China to measure theforces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on anincreasing or decreasing background force, generated by the test equipment itself.Indeed, in the UK when the background force changes were eliminated, in an effortto improve force measurement resolution, no EmDrive force was measured. Thiswas clearly a result of attempting to measure the forces on a fully static thruster,where T and R cancel each other.UK flight thruster measurements employ this principle to calibrate the backgroundnoise on the force balance prior to carrying out force measurements.What major external force is available in air that is not available in vacuum? Air vibrations which will generate a bigger Big to Small force than Small to Big force. Perfect for moving an EMDrive from IDLE mode into MOTOR mode when being tested in atmo but no help at all when testing in vacuum.The easier way to test this is to fill the Frustum with air and put it into a vacuum, or vice-versa. A sound proof enclosure with air and an evacuated Frustum can also show your effect. What doesn't seem to make any sense, is in a vacuum, no sound or vibration thrust is still seen although only 10% of the thrust in air. It's a piece of the puzzle that doesn't fit.
Quote from: DrBagelBites on 07/06/2015 10:45 pmI thought I would chime in with questions for the AIAA conference. I am going to be attending the event, so I will be able to report back to you guys about what happens, other questions that were asked, etc. Let me know of a couple of definite questions that anyone would want me to ask during the Q and A, AIAA Propulsion and Energy Forum and ExpositionHilton Orlando, Orlando, Florida...TUESDAY, JULY 28, 2015 NFF-04. Future Flight Propulsion Systems ...5:00 PM - 5:30 PMDirect Thrust Measurements of an EMDrive and Evaluation of Possible Side-Effects Martin TajmarSuggested questions to Prof. Tajmar arranged in order of importance:Q1. What is the explanation for the very low Q (only 50) in your EM Drive experiments?. Shawyer has reported Q=45,000 for his Demonstrator at your same tested frequency of 2.45 GHz. Is it because you did not use the usual waveguide isolator and 3-stub tuner between the magnetron and test article?Has Prof. Tajmar's team grossly over-coupled the RF input to the EM Drive copper truncated cone? Over-coupling is a matter of putting a larger resistive load on the resonant cavity by shunting more of the source load onto the cavity. Over-coupling can give an "equivalent" bandwidth which includes more than one mode.Was Tajmar trying to match it w/ ~ 50 MHz ? How wide was the high filament current magnetron bandwidth?. _____________________________________________________Q2. why your experiments show approximately 60% different thrust force measurements when the EM Drive was physically rotated 180 degrees from the "forward" thrust tests to the "reverse" thrust tests? Shouldn't the thrust be the same regardless of space orientation? Is this orientation-dependence indicative of an experimental artifact or a dependence on an external field ?_____________________________________________________Q3. Does Prof. Tajmar think that the reason why Shawyer and Yang claimed much higher thrust (over 1,000 to 10,000 times greater force/InputPower than what Tajmar measured) 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 ?_____________________________________________________Q4: What does Prof. Tajmar think about the "motor", "generator" conjecture of Shawyer?: that the EM Drive will not register a significant acceleration unless motivated to do so by vibrations of unspecified magnitude and frequency to produce initial acceleration in the direction pointing from the big base to the small base. Does Prof. Tajmar think that the reason why he measured much lower thrust is because he didn't vibrate the EM Drive to provide such initial condition?
I thought I would chime in with questions for the AIAA conference. I am going to be attending the event, so I will be able to report back to you guys about what happens, other questions that were asked, etc. Let me know of a couple of definite questions that anyone would want me to ask during the Q and A, AIAA Propulsion and Energy Forum and ExpositionHilton Orlando, Orlando, Florida...TUESDAY, JULY 28, 2015 NFF-04. Future Flight Propulsion Systems ...5:00 PM - 5:30 PMDirect Thrust Measurements of an EMDrive and Evaluation of Possible Side-Effects Martin Tajmar