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#3280 by RotoSequence on 17 May, 2018 14:24
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The accurate measurement techniques they are developing and ways to control various errors can have a variety of potential applications.
A small silver lining for a disappointing, but ultimately not surprising result.
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#3281 by PotomacNeuron on 17 May, 2018 15:15
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Quote
And so it remains infuriatingly ambiguous.
To me, it looked like a lean towards the negative, especially with the reference to earths magnetic field.
If the interaction with Earth magnetic field is the cause, they should be able to rotate their test apparatus (the entire thing, not the resonance cavity) horizontally to find an angle with which the interaction is minimized (theoretically, zero).
I am happy to see that they cited our father-and-daughter paper about the NASA experiment. -
#3282 by Star One on 17 May, 2018 16:53
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Quote
And so it remains infuriatingly ambiguous.
To me, it looked like a lean towards the negative, especially with the reference to earths magnetic field.
To quote the paper:QuoteThis clearly indicates that the “thrust” is not coming from the EMDrive but from some electromagnetic interaction.
People should read the paper for details, but basically, they did a good null test that showed comparable thrust. Looking at the data in the paper, it looks like out of the 2 mN/kW that they measured, if there was a hidden real signal I estimate it would be below 0.5 mN/kW. Keep in mind that 0.003 mN/kW is a laser pointer, by which point an experiment would have to account for all forms of emitted and incident radiation.
They make a good point in the conclusion, which I agree with and is one reason I continue to read this thread:QuoteAt least, SpaceDrive is an excellent educational project by developing highly demanding test setups, evaluating theoretical models and possible experimental errors. It’s a great learning experience with the possibility to find something that can drive space exploration into its next generation.
The accurate measurement techniques they are developing and ways to control various errors can have a variety of potential applications.
Does this equally apply to both types of drive? -
#3283 by meberbs on 17 May, 2018 17:06
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Does this equally apply to both types of drive?
In short yes:QuoteThis again indicates that there must be some electromagnetic interaction or thermally induced center of mass shift that is masking any real thrust value.
I recommend reading the paper, the details are different due to the different types of drive, but both had a null test that showed that any real signal was masked by other effects. Also, the Mach thruster had voltage not power listed, so I am not sure of its effective thrust/power ratio. Since it has an actual theory tied to it, and V^4 scaling with voltage, it may be the easier one to confirm or invalidate, since if they increase the voltage, it should rapidly increase the signal. In this case, expected thrust (0.02 uN) was well below the measured error source (0.6 uN). -
#3284 by Star One on 17 May, 2018 17:50
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Does this equally apply to both types of drive?
In short yes:QuoteThis again indicates that there must be some electromagnetic interaction or thermally induced center of mass shift that is masking any real thrust value.
I recommend reading the paper, the details are different due to the different types of drive, but both had a null test that showed that any real signal was masked by other effects. Also, the Mach thruster had voltage not power listed, so I am not sure of its effective thrust/power ratio. Since it has an actual theory tied to it, and V^4 scaling with voltage, it may be the easier one to confirm or invalidate, since if they increase the voltage, it should rapidly increase the signal. In this case, expected thrust (0.02 uN) was well below the measured error source (0.6 uN).
Thank you.
The paper looks to be paywalled? -
#3285 by meberbs on 17 May, 2018 23:25
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Thank you.
Not as far as I can tell (tried on multiple computers/networks).
The paper looks to be paywalled?
Here is the direct link from the "download pdf" button, maybe that will help. -
#3286 by spupeng7 on 18 May, 2018 01:37
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Does this equally apply to both types of drive?
In short yes:QuoteThis again indicates that there must be some electromagnetic interaction or thermally induced center of mass shift that is masking any real thrust value.
I recommend reading the paper, the details are different due to the different types of drive, but both had a null test that showed that any real signal was masked by other effects. Also, the Mach thruster had voltage not power listed, so I am not sure of its effective thrust/power ratio. Since it has an actual theory tied to it, and V^4 scaling with voltage, it may be the easier one to confirm or invalidate, since if they increase the voltage, it should rapidly increase the signal. In this case, expected thrust (0.02 uN) was well below the measured error source (0.6 uN).
It is a big step in the right direction when it is tested by a professional in a dedicated physics institution, considering the lack of theory supporting it. The last thing we want is false positives.
Still hopeful of contributing concepts to the theory I re-wrote my last essay and entered it into the GRF gravity essay competition. Attached for those curious enough to reconsider the fundamentals
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#3287 by Star One on 18 May, 2018 06:19
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Thank you.
Not as far as I can tell (tried on multiple computers/networks).
The paper looks to be paywalled?
Here is the direct link from the "download pdf" button, maybe that will help.
Thank you. -
#3288 by tdperk on 18 May, 2018 22:41
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Quote
And so it remains infuriatingly ambiguous.
To me, it looked like a lean towards the negative, especially with the reference to earths magnetic field.
Given Woodward's re-tests of his apparatus by turning it through 90 and 180 degrees, with a null result with respect to such orthogonality...
which must be present for the Earth's field to be the cause
...not so much. -
#3289 by Stormbringer on 19 May, 2018 03:26
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I don't know if it is old news to the participants in this thread but NBF has two articles on EM drives/MEGA Mach drives. One is what you are discussing now WRT Tajmar's paper but the other is about DR Sonny White saying he is making a new device operating at 400 Watts.
https://www.nextbigfuture.com/2018/05/sonny-white-at-eagleworks-scaling-emdrive-experiments-to-400-watts.html
there is also an article on Zurbin's dipole drive. -
#3290 by SeeShells on 19 May, 2018 04:13
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I don't know if it is old news to the participants in this thread but NBF has two articles on EM drives/MEGA Mach drives. One is what you are discussing now WRT Tajmar's paper but the other is about DR Sonny White saying he is making a new device operating at 400 Watts.
On youtube there is a great series (27 short videos) on Bohmian Mechanics by the members of the Workgroup Bohmian Mechanics at LMU Munich . They make some good arguments for it. Worth the watch.
https://www.nextbigfuture.com/2018/05/sonny-white-at-eagleworks-scaling-emdrive-experiments-to-400-watts.html
there is also an article on Zurbin's dipole drive.
Shell -
#3291 by Monomorphic on 19 May, 2018 11:45
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New PBS Spacetime episode on Noether's Theorem and The Symmetries of Reality
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#3292 by SeeShells on 19 May, 2018 12:52
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New PBS Spacetime episode on Noether's Theorem and The Symmetries of Reality
While I don't miss a episode and many times review past ones. Sadly the time restraints ~10 minutes limit what Matt O’Dowd can cover and as a result some content is left out.
On symmetry breaking I pulled up a paper I read last year and found fascinating:
Symmetry breaking in crossed magnetic and electric fields
C. Neumann, R. Ubert, S. Freund, E. Fl¨othmann, B. Sheehy,∗ and K. H. Welge†
Fakult¨at f¨ur Physik, Universit¨at Bielefeld, Universit¨atsstraße 25, D-33615 Bielefeld, Federal Republic of Germany
M. R. Haggerty and J. B. Delos†
Physics Department, College of William and Mary, Williamsburg, Virginia 23187
(December 25, 2017)
https://arxiv.org/pdf/physics/9701014.pdf
Even this paper can be supported by de Broglie-Bohm pilot wave theory. Which was reviewed by Matt O’Dowd in last weeks episode of Space/Time.
You have to agree there are still a lot of open questions in physics. I also find it interesting that Dr. Sonny White (EagleWorks) supports de Broglie-Bohm pilot wave theory.
My Very Best,
Shell
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#3293 by X_RaY on 19 May, 2018 15:06
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On the Anomalous Forces in Microwave Cavity-Magnetron Systems
March 2018
DOI10.13140/RG.2.2.14981.86243
Elio Battista PorcelliElio Battista PorcelliVicto S. FilhoVicto S. Filho
https://www.researchgate.net/publication/324023769_On_the_Anomalous_Forces_in_Microwave_Cavity-Magnetron_Systems -
#3294 by SeeShells on 19 May, 2018 15:47
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On the Anomalous Forces in Microwave Cavity-Magnetron Systems
My goodness. If you strap a magnetron to a Frustum you're going to get a mess. Heat, magnetic fields, DC currents and pulsing AC along with RF splattering all over base frequencies.
March 2018
DOI10.13140/RG.2.2.14981.86243
Elio Battista PorcelliElio Battista PorcelliVicto S. FilhoVicto S. Filho
https://www.researchgate.net/publication/324023769_On_the_Anomalous_Forces_in_Microwave_Cavity-Magnetron_Systems
Rfmwguy and Monomorphic and a few others found this out. If you're going to use a magnetron to get your RF, please clean up the power supply, fix the issues with the heater, thermally stabilize the magnetron, and get it away from the frustum!
Shell -
#3295 by LowerAtmosphere on 20 May, 2018 00:08
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https://www.researchgate.net/publication/325177082_The_SpaceDrive_Project_-_First_Results_on_EMDrive_and_Mach-Effect_Thrusters
Quote from their methodology:
"however, instead of hand-cut copper sheets and copper plated PCBs, our cavity geometry was manufactured from 1.5 mm thick copper sheets that were pressed into the correct geometry (see Fig. 6)."
They have forgotten skin depth and radiation pressure. Their experiment is flawed, or am I misinterpreting? Since the early days it was calculated to be ~66um skin depth meaning at bare minimum 1/8 inch = ~3mm of Copper is safe against buckling/leakage.
Cheers,
L.A. -
#3296 by SeeShells on 20 May, 2018 02:40
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https://www.researchgate.net/publication/325177082_The_SpaceDrive_Project_-_First_Results_on_EMDrive_and_Mach-Effect_Thrusters
L.A.,
Quote from their methodology:
"however, instead of hand-cut copper sheets and copper plated PCBs, our cavity geometry was manufactured from 1.5 mm thick copper sheets that were pressed into the correct geometry (see Fig. 6)."
They have forgotten skin depth and radiation pressure. Their experiment is flawed, or am I misinterpreting? Since the early days it was calculated to be ~66um skin depth meaning at bare minimum 1/8 inch = ~3mm of Copper is safe against buckling/leakage.
Cheers,
L.A.
Is this what you're talking about?
RF Skin depth should be <5um so a copper cavity thicker than that would be fine although a 6um copper cavity might blow away in a light breeze and of course deform under heat from the RF and modes.
Resistivity (μΩ cm)1.678
Relative Permeability: 0.999991
Frequency:2.45GHz
Skin depth 1.32 μm
Several other things stood out on these tests. For starters driving the frustum with a dinky 2 watts because they were having issues with thermals is the first. Looking at general published data in some of the tests (EW or even Monomorphic's) it's obvious that 2 watts would drop them into the noise of their test stand.
The other thing that struck me as odd when they presented at SSI 2017 November at the Aerospace Corporation in El Segundo, California. Dr. Martin Tajmar he even said that Shawyer had emailed him telling him that the mode and frustum geometry was wrong and it wouldn't produce thrust. Also Dr. Rodal asked what mode were they using and they were not sure what it was. starting 46:22
Mode setting, frustum dimensions, antenna placement, type of antenna are just a few critical items needed to be met. They honestly gave it a good try and Dr. Martin Tajmar said they would be trying it again. Also I would hope they get a thermal camera to verify the mode. Retesting? They need to.
Shell -
#3297 by spupeng7 on 20 May, 2018 06:10
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I don't know if it is old news to the participants in this thread but NBF has two articles on EM drives/MEGA Mach drives. One is what you are discussing now WRT Tajmar's paper but the other is about DR Sonny White saying he is making a new device operating at 400 Watts.
The paywall on White's paper is kind of steep ($120). Does anyone have a link to the PDF?
https://www.nextbigfuture.com/2018/05/sonny-white-at-eagleworks-scaling-emdrive-experiments-to-400-watts.html
there is also an article on Zurbin's dipole drive. -
#3298 by Stormbringer on 20 May, 2018 06:23
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not I; unfortunately.
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#3299 by Monomorphic on 20 May, 2018 14:35
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The paywall on White's paper is kind of steep ($120). Does anyone have a link to the PDF?
Attached is the PDF.
