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#2600 by mwvp on 19 May, 2016 05:38
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1) Shawyer claims that he used dielectrics and the performance was inferior to the one without dielectrics. Upon reviewing the dielectrics he used (from his patents) one concludes that Shawyer used inorganic dielectrics with very high relative permittivity =38, precisely the ones that would result in greater difference between Abraham and Minkowski
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3) When NASA used anisotropic organic polymers as an insert, having a relative permittivity closer to 2, which is closer to the value of vacuum or air than to the inorganic dielectrics used by Shawyer, they obtained the highest values of anomalous force.
4) Hence the value of the polymer inserts used by NASA cannot be justified by the relative permittivity, as this runs contrary to the experimental data of both NASA and Shawyer.
5) The value of NASA's polymer insert can instead be justified on the basis of Prof. Woodward's hypothesis: it is the piezoresistive effect and the ELECTRO-STRICTIVE FORCE of the material that matters rather than the difference in permittivity. The experimental data from Shawyer and NASA indicate that this is not a dielectric effect. Hence the experimental data does not support the Abraham/Minkowski theory (polymer with rel.permittivity=2 gives much higher effect than inorganic dielectric with rel.permittivity=38), it rather rules against it, and instead may support Prof. Woodward's hypothesis.
What had occurred to me was the difference between Abraham and Minkowski momenta, the difference between the E and M fields of the vacuum and dielectric that creates a force, not one better than the other, but optimized when they're equal. In contrast, the first term in Shawyers force equation scales the force with the Abraham momentum; he considers that most important and Minkowski momentum deleterious to force.
With a very high Er, more force wouldn't result according to my conjecture. But anyways, on second thought, I'm floating an abstraction; the dielectric is attached to the frustrum which reflects and anchors the vacuum field in space. Once again, its pulling yourself up by your bootstrap because as the frustrum moves, it keeps the same field centered around the dielectric, so it just creates stress between the frustrum and dielectric. Unless, as I keep insisting, thrust is a consequence of unbalanced momentum resulting from acceleration and Doppler shifts in a dissipative, dispersive anisotropic frustrum.
I think I understand Woodward; I first read a couple of his papers over 10 years ago. I'll have consider how transient mass fluctuations could be in play with dielectric electrostriction to produce thrust in the EM Drive. -
#2601 by mwvp on 19 May, 2016 05:48
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Dr. Rodal, at the end of the Ames talk Sonny describes moving forward and mentions "phase lock loop", forgive my high school physics only, but would phase lock looping eliminate or mitigate the issues associated with modes being too "close" to one another? Not to mention your above mentioned antenna looping and positioning advice. Your help is greatly appreciated. FL (below attached image of "moving forward" frustum)
Hopefully Dr.Rodal won't mind a member of the NSF "hive mind" answering your question.
A "phase lock loop" does help in maintaining a constant output frequency. Unfortunately one of the biggest problems seen with these DIY resonant cavities is thermally induced deformation.
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If I may be excused for buzzing in from the hive too;
PLL's are ubiquitous, prolific, and it's deviant NOT to use them.
What I think would be helpful in locking onto a difficult mode would be to design antenna(s)/probe(s) to sense the desired mode, and danger-close undesired mode(s), apply the signals to summing and difference amplifiers to control the PLL's error voltage, thus locking onto the desired mode and discriminating against the undesired mode(s). -
#2602 by spupeng7 on 19 May, 2016 06:10
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Interesting plot. I am looking for the best way to chart current over the entire inside surface of the frustum for a productive resonance. Is the Poynting vector equal to current? -
#2603 by TheTraveller on 19 May, 2016 06:26
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1) What matters is the location of the excitation loop. It should be located preferentially where the magnetic field intensity is highest, and where its gradient is minimum (so that positioning is not as critical), and located precisely so that it is aligned as well as possible with the direction of the magnetic field. The loop has to be made precisely and aligned precisely (the alignment is not that easy to achieve). As to the best location it depends on the geometry of the fustrum (the conical angle and the spherical radial distance to the apex of the small and large ends). X-Ray conducted some studies in the past (sorry it would take me too long to search for those links, no good way to search massive threads at NSF.)
That is my experience.
Unlike EW that use a full loop placed away from the side wall, I use a 1/2 loop that is tight against the side wall. Like EW, the loop can be rotated. Which I do as 1st to obtain lowest rtn loss, then when under power from the Rf amp, rotated to obtain best VSWR, then when producing thrust, rotated to produce best thrust. And while all the above also varying freq to obtain the best result at each stage. See attached.
Ideally need a fine stepper motor attached to the loop rotate system to automate all this tuning, which while it sounds like a pain, is very necessary.
Note the antenna position tuner used on a prototype of the Flight Thruster as attached. Note the crank arm on the left end of the rod that goes inside the frustum.
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#2604 by A_M_Swallow on 19 May, 2016 09:31
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Dr. Rodal, at the end of the Ames talk Sonny describes moving forward and mentions "phase lock loop", forgive my high school physics only, but would phase lock looping eliminate or mitigate the issues associated with modes being too "close" to one another? Not to mention your above mentioned antenna looping and positioning advice. Your help is greatly appreciated. FL (below attached image of "moving forward" frustum)
The problem is the phase lock loop circuit is being fooled by the modes being too close together. The circuit assumes that the frustum has only one mode and tries to maximise the output. Where the modes are far apart the only one mode approximation works. Where two or more modes are close the circuit sometimes detects the other mode and tries locking on to it. This happens repeatedly. Consequently the loop drives like a drunk and the equipment ends up in neither mode. -
#2605 by TheTraveller on 19 May, 2016 10:03
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Dr. Rodal, at the end of the Ames talk Sonny describes moving forward and mentions "phase lock loop", forgive my high school physics only, but would phase lock looping eliminate or mitigate the issues associated with modes being too "close" to one another? Not to mention your above mentioned antenna looping and positioning advice. Your help is greatly appreciated. FL (below attached image of "moving forward" frustum)
The problem is the phase lock loop circuit is being fooled by the modes being too close together. The circuit assumes that the frustum has only one mode and tries to maximise the output. Where the modes are far apart the only one mode approximation works. Where two or more modes are close the circuit sometimes detects the other mode and tries locking on to it. This happens repeatedly. Consequently the loop drives like a drunk and the equipment ends up in neither mode.
To inject a bit of experimental reality, different modes force different cutoff and guide wavelength which alters the mode shape and where the idea excitation point is.
I don't use a phase lock loop but instead use a smart software algorithm that monitors the frustum, Rf drive parameters, it's environment and adjusts the best freq tune as per mouse clicked desire.
Roger did reveal a bit of the control systems SPR developed as per attached.
I added feedback from forward and reflected Rf energy in the Rf drive system feeding the coax, feeding the frustum. Future build will have almost no distance from Rf amp output to internal cavity coupler, which exits any coax feed line issues.
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#2606 by Monomorphic on 19 May, 2016 13:28
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p.s. Just read Phil's 2G post...He already mentioned an accelerometer! Sorry about that Phil...
We discussed accelerometers on that other forum. We were looking at high resolution accelerometers that also have gyros, magnometers and barometers. There are a number of different boards here:
http://www.robotshop.com/en/catalogsearch/result/index/?dir=desc&order=stats_sales_order_count&p=1&q=accelerometer
This one would work nicely: http://www.robotshop.com/en/phidgetspatial-precision-3-33-high-res-3-axis-compassgyroscopeaccelerometer.html -
#2607 by gustavo on 19 May, 2016 16:20
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A friend asked me to review this manuscript by gustavo Colheri Uchida. Attached please find my review report. Thanks!
Thank you for posting your review,
It is for sure of a great value to my revisions
For the case of the cylinder where thrust is zero, I've looked in the solution matrix. There is something happening. Thrust is oscillating when the beam hits the ends, as can be seen in image attatched. The column 4 is z component of force in collision point, column 5 is the resulting sum of thrust in all collision points because we are considering a continuous beam.
For cylinder case, depending on where the beam finishes its trajectory, a resulting thrust is observed. This should be considered in my paper.
However, thrust has not significantly changed with your expression for radiation pressure. Conservation of momentum is still been violated. And, when considering a perfect mirror, the (1-η) turns to zero, and the expressions returns to the form I've written.
Frankly I do not know why the truncated cone is resulting in thrust.
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#2608 by FattyLumpkin on 19 May, 2016 18:28
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X_Ray, would you please chime in with regard to the discussion pertaining to antenna placement in exciting TE012? thank you. FL
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#2609 by X_RaY on 19 May, 2016 18:49
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X_Ray, would you please chime in with regard to the discussion pertaining to antenna placement in exciting TE012? thank you. FL
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1410718#msg1410718
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412912#msg1412912
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1411521#msg1411521
All of this will work. Can't say what's "the best" method. It depends on too much parameters, maybe its enough work for a full master thesis.
We had discussions this over and over within the first few threads. Much work to read all of it but quite interesting
EDIT
For this Feko run (pic above and below) I used two dipoles within the center of the biggest E-field value, near the big end plate, into φ direction. I think its reasonable to share the results as well as all the details of these simulations, there is no other way for the public to understand what happens.
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#2610 by Monomorphic on 19 May, 2016 19:03
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Frankly I do not know why the truncated cone is resulting in thrust.
One thing I noticed in my laser simulations is that if there are equal number of bounces on the small end and the large end, any bounces off the side walls should result in movement toward the small end - since the
force caused by reflected photons is perpendicular to the wall. Then it is just a simple matter of recycling the photons as many times as possible before absorption to increase thrust. This is easier to see in the first few dozen reflections.
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#2611 by zen-in on 19 May, 2016 19:29
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***General EMDrive Info***
A few pages back, I had asked questions about the Tau-Zero foundation, now apparently merged with centauri-dreams.org. My initial question was how/if they followed EMDrive at all. Just discovered Marc Millis, founder of Tau-Zero (now with Paul Gilster at Centari-dreams) and ex-NASA Glenn BPP project lead recently stated his opinion on Dr White's work at EW. Follow link for full context. This probably explains their lack of their following the NASA EW work:
Marc Millis March 23, 2016 at 13:00 (abbreviated for posting here, follow link for full context - Dave)
"Here are some representative facts about Sonny’s work:
– Sonny has chosen to field his results via blogs, internal papers (not peer reviewed) and press interviews instead of through publications where the work will be scrutinized for rigor.
– Sonny names equipment after himself and coworkers (“White–Juday warp-field interferometer”).
– On the key component of his tests – the device to create the space warp – he has withheld disclosure.
– When inviting Sonny to submit a chapter to our book, where I asked him for an impartial assessment of Woodward’s Mach Thruster (of which he had done some tests), I got instead an advocacy pitch for one of Sonny’s theories.
So from the above, you can probably conclude that I no longer devote my time to following Sonny’s work. If he changes how he works – by being more impartial and rigorous and by subjecting his work to careful review before publishing, then I will reconsider."
http://www.centauri-dreams.org/?p=35243
My notes: centauri-dreams best I can tell is a (pseudo) think tank for interstellar spaceflight and has a publisher's biz model for funding. While understanding the natural reluctance to acknowledge EW peer-review rigor, C-D itself is a blog and prospective publisher, which seems to be a sore spot for Millis when White did not provide a Woodward assessment. Not sure why White was not asked to write about an EW assessment, but the Mach-Effect Thruster which he had less experience with.
You asked Millis what his opinion was and he gave you an honest answer. Thanks for informing us. -
#2612 by FattyLumpkin on 19 May, 2016 19:33
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Dave, re Sonny and Marc, as you have seen I reviewed the two videos of Sonny most recently displayed here at NSF, and asked several questions of Dr. Rodal re. several statements made on them. While hopes are high for success in this endeavor, as noted by Dr. Rodal, some of the statements Sonny made could not be explained. "20 Newtons of continuous thrust" is unequivocal, but indeed we are left to suppose that he was referring to the MLT (which would be awesome notwithstanding), but it appears there was some conflation between devices and reported thrust results. As relaxed as Sonny is in his speaking style, one might suggest the there is a "air of glibness" about him, but he was unequivocal about the technology generating enough thrust to make very fast trips to the outer planets and even interstellar voyages. Additionally, he did state that EWL was constructing test articles to send out to various institutions in the US for independent validation. As aforementioned this would lead one to conclude that the tech was generating > 100 micro Newtons of thrust since the test stand at JPL is not as sensitive as the pendulum and EWL.(if memory serves) Finally the statement about moving from TRL 2 to TRL 3 (there's also no wiggle room there.)
I for one will remain hopeful and look forward to your Shell's and Monomorphic's results. -
#2613 by zen-in on 19 May, 2016 20:22
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Yes, I guess I read that wrong. It would seem that Marc anticipated your public question a few weeks later.
Except I didn't ask him. Somebody posed this weeks ago and he responded. I just found it.***General EMDrive Info***
A few pages back, I had asked questions about the Tau-Zero foundation, now apparently merged with centauri-dreams.org. My initial question was how/if they followed EMDrive at all. Just discovered Marc Millis, founder of Tau-Zero (now with Paul Gilster at Centari-dreams) and ex-NASA Glenn BPP project lead recently stated his opinion on Dr White's work at EW. Follow link for full context. This probably explains their lack of their following the NASA EW work:
Marc Millis March 23, 2016 at 13:00 (abbreviated for posting here, follow link for full context - Dave)
"Here are some representative facts about Sonny’s work:
– Sonny has chosen to field his results via blogs, internal papers (not peer reviewed) and press interviews instead of through publications where the work will be scrutinized for rigor.
– Sonny names equipment after himself and coworkers (“White–Juday warp-field interferometer”).
– On the key component of his tests – the device to create the space warp – he has withheld disclosure.
– When inviting Sonny to submit a chapter to our book, where I asked him for an impartial assessment of Woodward’s Mach Thruster (of which he had done some tests), I got instead an advocacy pitch for one of Sonny’s theories.
So from the above, you can probably conclude that I no longer devote my time to following Sonny’s work. If he changes how he works – by being more impartial and rigorous and by subjecting his work to careful review before publishing, then I will reconsider."
http://www.centauri-dreams.org/?p=35243
My notes: centauri-dreams best I can tell is a (pseudo) think tank for interstellar spaceflight and has a publisher's biz model for funding. While understanding the natural reluctance to acknowledge EW peer-review rigor, C-D itself is a blog and prospective publisher, which seems to be a sore spot for Millis when White did not provide a Woodward assessment. Not sure why White was not asked to write about an EW assessment, but the Mach-Effect Thruster which he had less experience with.
You asked Millis what his opinion was and he gave you an honest answer. Thanks for informing us. -
#2614 by jmossman on 19 May, 2016 20:31
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Frankly I do not know why the truncated cone is resulting in thrust.
One thing I noticed in my laser simulations is that if there are equal number of bounces on the small end and the large end, any bounces off the side walls should result in movement toward the small end - since the
force caused by reflected photons is perpendicular to the wall. Then it is just a simple matter of recycling the photons as many times as possible before absorption to increase thrust. This is easier to see in the first few dozen reflections.
If I recall, there was an attempt to use similar simple modeling technique from a CAD physics package with bouncing/ricocheting ?balls? inside of various frustum-related shapes. I suspect the sum of forces due to simple impacts with the walls would closely match the ray-tracing approach (i.e. as total area of "sloped sides" increases relative to the end plates). I don't remember how many threads back the bouncing ball simulation was attempted.... maybe someone else with a better memory than I can remember more information.
I vaguely recall that more of a cone shape was better than a frustum in the simplified simulation.
Part of the original critique involved (from my failing memory): how the reduced energy of each ricochet was being modeled, how the initial momentum/energy of the ball injection was being accounted for, and how the initial direction of said ball injection was being chosen. -
#2615 by Monomorphic on 19 May, 2016 20:46
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If I recall, there was an attempt to use similar simple modeling technique from a CAD physics package with bouncing/ricocheting ?balls? inside of various frustum-related shapes. I suspect the sum of forces due to simple impacts with the walls would closely match the ray-tracing approach (i.e. as total area of "sloped sides" increases relative to the end plates). I don't remember how many threads back the bouncing ball simulation was attempted.... maybe someone else with a better memory than I can remember more information.
I vaguely recall that more of a cone shape was better than a frustum in the simplified simulation.
Part of the original critique involved (from my failing memory): how the reduced energy of each ricochet was being modeled, how the initial momentum/energy of the ball injection was being accounted for, and how the initial direction of said ball injection was being chosen.
That was also me. That had to do with explaining anomalous movement in physics simulations involving bouncing particles. But in that case, the movement was towards the bid end. It turned out to be dynamic resistance properties - cheats used to simulate stretching and bouncing - that lead to the frustum movement. That problem was solved.
These new laser simulations are different. They predict movement in the direction of the small end (just like the microwave emdrive). It works equally well with injection from the small end, so initial momentum/energy can add to the effect.
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#2616 by Star One on 19 May, 2016 21:16
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Emdrive, Cannae and MLF thrusters have all been discussed to some extent or another over the years on Centauri Dreams (CDs) which is still up and running. CDs is part of the Tau Zero Foundation.
They are more interested in other things these days of you follow the articles on there over any amount of time. -
#2617 by gustavo on 19 May, 2016 22:02
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One thing I noticed in my laser simulations is that if there are equal number of bounces on the small end and the large end, any bounces off the side walls should result in movement toward the small end - since the
force caused by reflected photons is perpendicular to the wall. Then it is just a simple matter of recycling the photons as many times as possible before absorption to increase thrust. This is easier to see in the first few dozen reflections.
Monomorphic, on your simulation for rounded endplates the angles of incidence are equal on small and big end? Can you check this?
For a equal number of bounces on small and big end, and equal angles of incidence, resulting force between small and big end is zero, and bounces on sidewalls does produce force towards small end.
But, I've run a simulation with 50,000 reflections (flat endplates) for a given initial beam trajectory, and counted the number of reflections on small end, big end and sidewalls:
Small end: 3,121 reflections, average angle of incidence: 36.19º
Large end: 15,830 reflections, average angle of incidence: 35.67º
Sidewall: 31,049 reflections, average angle of incidence: 30.96º
Dimensions of cavity:
Rt: 250mm
Rb: 95mm
H: 375mm
Initial position: [0, 3, 100]
Initial direction: [10, 0, 0]
Freq: 2.4 Ghz
Power: 1000W
Mirror efficiency: 99.99%
Thrust: 1.07 mN towards small end
Number of bounces on small and big end are not equal, still, we have 15,830 bounces that produces force towards large end, and 34,170 that produces force towards small end.
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#2618 by FattyLumpkin on 19 May, 2016 23:48
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Dave, when might we expect your first video post? Re Centauri Dreams following the findings of T.E.S.S. 2017-2019 (assuming the mission is successful) I would think they might seriously focus on propulsion and design! JWST 2018 (also if successful) will point to where it is we might/should go...It would be a shame if earth 2.0 were found < 10 LYs away and not even have a suggestion as to how one (probe or other) might get there to check it out.
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#2619 by SteveD on 20 May, 2016 01:09
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Google Science Fair Projects 2016 - EMDrive
So the English speaking science fair team is reporting 14.7mN of thrust. Do we have any more information on their build? I think the first question that needs to be answered is did they measure 14.7 mN in a DOWNWARD direction. I note that this result seem consistent with TT's observations of 20 mN/kilowatt.
