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#3000
by
mwvp
on 20 Nov, 2016 19:19
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Ah Ha!
I read something very interesting in EW's latest paper @
http://arc.aiaa.org/doi/pdf/10.2514/1.B36120pg. 3:
"The change in phase angle over frequency [dispersion!] was also calculated, and a new parameter dubbed the phase angle quality factor was developed to help quantify the characteristics of a given resonance condition. The phase angle quality factor was the change in phase angle over a given frequency range, and it was determined using the phase plot fromVNA and only considering the region of the steepest phase angle change centered on the resonance. Figure 4 depicts ...The bottom-left pane is the variation in phase angle for the system, and the bottom-right pane is the group delay.
The tuning study determined that, for this particular tapered test article, optimal thrust was present if the system had a quality factorat least several thousand and the maximum phase angle quality factor ["phase angle quality factor" - dispersion!] that could be achieved."
Hmmmm, now, where have we heard and seen anything like this before? Oh! Now I remember:
http://forum.nasaspaceflight.com/index.php?topic=39772.msg1509852#msg1509852from: 1303.0733 pg 20
Traveller's notes about Roger's observation of a narrower tunning max. thrust range than resonance BW. Because force depends on the gradient, as well as amplitude of the phase slope. At peak resonance, there is no slope, no gradient. As is evident from the Optomechanics paper.
Now, if tests are done on a rotary fixture that can permit the frustrum to accelerate, I predict enhanced force/power figure of merit consequent from negative inertial resistance! Anisotropic frequency dissipation enables a net group-velocity towards the base, producing minor thrust in a static test frame, and enhanced thrust in an accelerating frustrum as doppler shifted sidebands spread, along with enhanced guide wavelength spread (on a steep dispersive phase-slope) enhancing lower sideband dissipation.
As discussed by Bradshaw in:
http://arxiv.org/abs/1005.5467v1"Doppler shifts may become large in a dispersive medium as the velocity of the Doppler shifting surface approaches the group velocity." in my renouned, hastilly blurted post:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1471229#msg1471229If you understand the roles of anisotropic dispersion and dissipation of doppler shifted sidebands in an accelerated frame, it all makes sense using, as Shawyer's said, conventional SR and Maxwell's EM. No new physics needed.
See? I told you. But nyooooooooooooo. Nobody listened.
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#3001
by
X_RaY
on 20 Nov, 2016 19:20
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RotoSequence:
I need a clarification about the meaning of your below statement.
"It doesn't matter that force was measured, because they haven't shown divergence through a different, but likewise TM212 resonant geometry - which means they haven't proven that the conical cavity geometry uniquely affects more than the resonance mode, frequency, etc in their experiment."
I performed an experiment that did not make it into the final version of the EW in-vacuum report that demonstrated that if the TM212 mode is not excited in the same copper frustum test article utilizing the same RF power levels as when it is exciting the TM212 mode, its thrust production was greatly reduced, see attached slides. Is that what you are calling not demonstrating "divergence through a different, but likewise TM212 resonant geometry"?
Paul March, Friendswood, TX
I have been following this research for a few years now. In the AIAA paper I noticed an interesting discrepancy. All of the "forward" graphs show the distance measured by the optical displacement sensor increasing when RF is turned on. This is the opposite of the capacitor force. Fig. 2 (first graphic below) in the paper shows the two devices mounted on the same X-Y-Z stage on the small end side of the fustrum. In the paragraph labeled "5. Forward Thrust Overview" it says the forward thrust makes the device shown in Fig 14 (second graphic below) move to the left. This is the same movement that Shawyer reported. If the configuration shown in Fig. 2 was ever used the accepted direction of the em-drive thrust would move the mirror closer to the optical displacement sensor, resulting in a decrease in the distance measurement. However what we see in all the graphs is the opposite. This discrepancy might just be oversimplification on their part and they may actually have the position sensor at the big end side and the capacitor force sensor on the small end side as shown in Fig 2. I will read the paper again to see if that is stated.
Another interesting statement in their paper occurs in the same paragraph 5 I referred to above
quoted from AIAA paper
"
5. Forward Thrust Overview
The tapered RF test article was mounted on the torsion pendulum as shown in Fig. 14. Forward thrust was defined as causing displacement to the left in the photograph. Viewed from above, the torsion arm moved clockwise, causing the mirror attached to the torsion arm to move away from the optical displacement sensor, which appears as an upward motion or positive displacement in the plots of displacement vs time in Figs. 9 and 13. This displacement was also in the same direction as that due to the CG shift from thermal effects.
"
end quote
They are saying the displacement due to thermal change in CG is in the same direction as the measured "thrust". Yet there have been no calibration or baseline experiments done to determine how much of the measured thrust is due to this thermal effect. Thermal expansion could be a couple of orders of magnitude greater than the displacement they are claiming indicates an em-drive thrust effect.
I also disagree with the use of the term "impulsive thrust". All the graphs show the capacitive test force. This is a step response. The first part, where there is a falling edge and undershoot is the impulse response of a damped second order system, ie: the torque pendulum. The rising edge also shows the same impulse response. The whole waveform is the step response of a second order system. Any force applied to the torque pendulum has to have this step response. What we see when RF is switched on is the step response of a first order system. I don't see any indication of a second order step response in the "thrust" waveform. The thermal effects have not been measured independently. It is entirely possible the "thrust" waveform is completely due to thermal effects; eg: the change in CG as mentioned in paragraph 5 above.
**Corrected**
Zen-in:
"They are saying the displacement due to thermal change in CG is in the same direction as the measured "thrust". Yet there have been no calibration or baseline experiments done to determine how much of the measured thrust is due to this thermal effect. Thermal expansion could be a couple of orders of magnitude greater than the displacement they are claiming indicates an em-drive thrust effect."
Once again and IMO, a large part of my calibration work was not given sufficient coverage in this report after Dr. White and the AIAA reviewers got through with it. These calibration efforts on my part addressed and quantified the magnitude of the torque pendulum's center of gravity (cg) shifts due to the temp rise and fall driven thermal expansions of the copper frustum and the counter thermal expansion of RF amplifier's aluminum heat-sink and aluminum case. (The copper frustum was mounted on one side of an 0.090" thick 6061 aluminum spine plate while the RF amplifier and its heat-sink were mounted on the opposite side of this aluminum spine plate. A few slides with some of this thermal cg shift data is appended below and I'll post more as need, but in short the graphic signatures you are seeing in this EW in-vacuum report consist of an impulsive signal riding on top of the thermally driven TP cg shifting signal as defined in the force diagrams.
Best, P.M.
The diagram looks like based on measurement data and not calculated thermal expansion of the materials, right?(otherwise the µm displacement should be equal in bothe directions).
Interesting piece of the puzzle!
Thanks.
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#3002
by
as58
on 20 Nov, 2016 19:38
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I don't understand the force measurement procedure. What justification is there that the break in slope represents the peak thrust? Why does it take so long, ~20 s to reach, when for calibration pulses the maximum displacement is reached in less than five seconds? And when the RF power is turned off it looks even stranger. Look at Fig. 7, where the 29 uN calibration pulse at ~160 s is very obvious and starts steeply. However, the claimed disappearance of 106 uN EM Drive thrust looks much smoother.
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#3003
by
Star-Drive
on 20 Nov, 2016 19:41
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X_Ray:
"The diagram looks like measurement data and not calculated thermal expansion of the materials, right? (Otherwise the µm displacement should equal in both directions).
Interesting piece of the puzzle! Thanks."
Correct, my EW Torque Pendulum thermal expansion magnitude experiments and calculations are documented in a series slides with the first few attached to this post.
Best, Paul M.
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#3004
by
RERT
on 20 Nov, 2016 20:14
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Flux Capacitor - your reference gives 4T fuel at 5% enrichment, my sum gave 0.2T at 100% enrichment, which is good enough reconciled for me. I've no idea which you would build in practice, but either way it seems feasible. 100 year journeys are hard for other reasons, anyway.
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#3005
by
X_RaY
on 20 Nov, 2016 20:23
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
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#3006
by
rfmwguy
on 20 Nov, 2016 20:32
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
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#3007
by
Star One
on 20 Nov, 2016 20:33
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
Can we expect any published results in 2017 do you think?
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#3008
by
rfmwguy
on 20 Nov, 2016 20:40
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
Can we expect any published results in 2017 do you think?
Good question which I don't have enough info to answer confidently. This may depend on Paul's possible collaboration with others and how they wish to proceed. I know Paul is anxious to get additional ground based testing complete then into LEO. Perhaps Tajmar might fulfill this aspect while Paul focuses on the mission. This is my best guess
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#3009
by
Star One
on 20 Nov, 2016 20:41
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
Can we expect any published results in 2017 do you think?
Good question which I don't have enough info to answer confidently. This may depend on Paul's possible collaboration with others and how they wish to proceed. I know Paul is anxious to get additional ground based testing complete then into LEO. Perhaps Tajmar might fulfill this aspect while Paul focuses on the mission. This is my best guess
Is Paul trying to get something like a cubesat okayed then?
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#3010
by
rfmwguy
on 20 Nov, 2016 20:42
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X_Ray:
"The diagram looks like measurement data and not calculated thermal expansion of the materials, right? (Otherwise the µm displacement should equal in both directions).
Interesting piece of the puzzle! Thanks."
Correct, my EW Torque Pendulum thermal expansion magnitude experiments and calculations are documented in a series slides with the first few attached to this post.
Best, Paul M.
Welcome back "stranger".
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#3011
by
rfmwguy
on 20 Nov, 2016 20:44
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
Can we expect any published results in 2017 do you think?
Good question which I don't have enough info to answer confidently. This may depend on Paul's possible collaboration with others and how they wish to proceed. I know Paul is anxious to get additional ground based testing complete then into LEO. Perhaps Tajmar might fulfill this aspect while Paul focuses on the mission. This is my best guess
Is Paul trying to get something like a cubesat okayed then?
Yes, his webpage is here:
https://hackaday.io/project/10166-flying-an-emdrive
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#3012
by
Star One
on 20 Nov, 2016 20:47
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Is there any new info about the vacuum test of Paul Kocyla at dresden university??
Yes, mechanical rework of assembly to offset cooling difficulties. Think Paul mentioned switching to a higher output device that will run cooler at or near original power levels.
Can we expect any published results in 2017 do you think?
Good question which I don't have enough info to answer confidently. This may depend on Paul's possible collaboration with others and how they wish to proceed. I know Paul is anxious to get additional ground based testing complete then into LEO. Perhaps Tajmar might fulfill this aspect while Paul focuses on the mission. This is my best guess
Is Paul trying to get something like a cubesat okayed then?
Yes, his webpage is here: https://hackaday.io/project/10166-flying-an-emdrive
Thanks for that link.
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#3013
by
otlski
on 20 Nov, 2016 21:26
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In order for a thermal shifted CG to cause a torque artifact, an out of level condition of the torsion pendulum's axis must be present at that particular time. A CG shift while perfectly level will not cause an anomalous torque. An out of level condition without a CG shift will not cause a torque.
Furthermore, both the moment magnitude of the thermo CG shift, and its vector relative to the "high point" of the out of level will define how the system reacts. For example, it the CG shifts directly toward the low point of the out of level, little torque will be generated. If the CG shifts in a vector 90 degrees from that low point, the maximum error effect will be seen.
Characterizing the system the way Paul March did is a reasonable step. However, it is important to understand that there were no changes in the experiment configuration, which shifted the CG, from that calibration to the testing regimen. Some lingering questions for example. Was the bar of aluminum that the cal weight was slid down present during the thrust test as well as the thermo cal? If not then the addition of this component can shift the high point to a new spot muddying the thermo calibration run. Was the thermo cal done with the torsion pendulum slid out of the chamber? How level was it outside the chamber? How level inside the chamber? How repeatable was the level. Did all locations share the same high point or did it shift to a new spot as it was slid into place?
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#3014
by
ThinkerX
on 20 Nov, 2016 23:29
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Star Drive -
Occasional reports have surfaced here of an EM Drive rotary test experiment by either Eagleworks or NASA (apologies, my info here is sparse at best).
Can you confirm or deny such EM Drive rotary experiments, and if so, make even general commentary on the results?
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#3015
by
rfmwguy
on 20 Nov, 2016 23:31
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Just a coincidence...60 year old Disney Sunday evening TV show mentions emdrive by name @ 16:31.
Also talks about going to Mars, quite relevant to today's discussions...60 years...sad we never made it in that time. People were so hopeful about space at one time. Enjoy a minor diversion this Sunday evening.
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#3016
by
Mark7777777
on 20 Nov, 2016 23:56
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Quick question:
On page 1 of Rodger Sawyer's latest patent, it talks about getting superconducting thrust of 30N per 1KW of power. However his thrust table on page 7 shows an average superconducting thrust of 0.326N per 1KW. Am I comparing correctly?
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#3017
by
francesco nicoli
on 20 Nov, 2016 23:58
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So, very interesting discussion, but after the publication of the paper, I would be glad if someone would make a short, non-tecnical post on what the new paper shows ns does not, and what are the limitations of this research set... I think the community would greatly benefit from stating clearly the state of the art!
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#3018
by
Star-Drive
on 21 Nov, 2016 00:35
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Star Drive -
Occasional reports have surfaced here of an EM Drive rotary test experiment by either Eagleworks or NASA (apologies, my info here is sparse at best).
Can you confirm or deny such EM Drive rotary experiments, and if so, make even general commentary on the results?
The Eagleworks (EW) team including me was in the middle of performing a battery-powered, Cavendish-Balance (C-B) "free-flyer" test on a rotary air-bearing experiment utilizing the EW Integrated Copper Frustum Test Article (ICFTA) used for the EW in-vacuum tests when I retired from the lab at the end of September. Their initial test results in the forward and reverse rotational directions looked encouraging, but it was contaminated with swirl torque "noise" being induced by the less than stellar spherical air bearing we had initially procured at the lowest cost. Now I, with the rest of us, will have to wait for the current civil-servant EW team to finish this C-B test series and report on it in the peer-reviewed journals, which could be a year or more away, and that is only if NASA/JSC continues to support the EW lab's activities.
Best, Paul M.
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#3019
by
OnlyMe
on 21 Nov, 2016 01:19
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Star Drive -
Occasional reports have surfaced here of an EM Drive rotary test experiment by either Eagleworks or NASA (apologies, my info here is sparse at best).
Can you confirm or deny such EM Drive rotary experiments, and if so, make even general commentary on the results?
The Eagleworks (EW) team including me was in the middle of performing a battery-powered, Cavendish-Balance (C-B) "free-flyer" test on a rotary air-bearing experiment utilizing the EW Integrated Copper Frustum Test Article (ICFTA) used for the EW in-vacuum tests when I retired from the lab at the end of September. Their initial test results in the forward and reverse rotational directions looked encouraging, but it was contaminated with swirl torque "noise" being induced by the less than stellar spherical air bearing we had initially procured at the lowest cost. Now I, with the rest of us, will have to wait for the current civil-servant EW team to finish this C-B test series and report on it in the peer-reviewed journals, which could be a year or more away, and that is only if NASA/JSC continues to support the EW lab's activities.
Best, Paul M.
... and that is only if NASA/JSC continues to support the EW lab's activities.This last does not sound encouraging. Is there a real risk that NASA/JSC is going to pull the plug on EW?
