Author Topic: EM Drive Developments - related to space flight applications - Thread 7  (Read 1680691 times)

Offline Tetrakis

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4) Given Yang's results, it is clear that, for any EM Drive test to gain credibility, it should be performed in:

4a) torsional pendulum (teeter-totters and scales can be shown to be flawed devices, as known in Aerospace R&D of over 50 years of testing in micro-thrusters)

4b) self-integrated power source (i.e. battery powered) in the same moving platform (having the power come from a stationary source is fundamentally flawed from a conservation of energy viewpoint).[/b]


(*) As repeatedly stated, people should not be confused by reports that NASA "MAY" ("may" in capital letters) have obtained some thrust without a polymer insert without taking into account:

*a) the figure of merit for EM Drive's is the force/Input power.  The numerical value of different test results should be compared on the basis of the force/InputPower achieved (and not based on "force" without taking into account the power input)

*b) the statistical significance of any value of force/inputPower

*c) the testing apparatus: tests performed at NASA's teeter-totter should not be compared to tests performed on NASA's torsional pendulum.  Experimental values should be compared in the same testing device, preferably the torsional pendulum, as is known in Aerospace R&D of micro-thrusters, for over 50 years, that the torsional pendulum is the best type of measurement and the teeter-totter is among the worst.

*d) as I have shown elsewhere, the function of the polymer insert in NASA's EM Drive was never to be a dielectric, due to its electric permittivity.  NASA obtained insignificant force/InputPower when using inorganic dielectrics with relative electric permittivity ~38 as used by Shawyer.  Such dielectrics reduce the Q.  Instead NASA used polymers with relative electric permittivity ~2 closer to the value of air or vacuum ~1.  The polymer insert in NASA'and Aachen teams EM Drives should not be described as "dielectrics". That is a false narrative.  Instead their function may be justified on the basis of Woodward's theory, of Dr. White's QV theory.

Can you add a 4. c) High vacuum

As I mentioned in a previous post under low vacuum the remaining pressure is on the same order of magnitude as the EW "signal"
« Last Edit: 05/01/2016 02:33 pm by Tetrakis »

Offline zen-in

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Abstract from Yangs Paper:

Quote
Abstract: In order to explore the thrust performance of microwave thruster, the thrust produced by microwave thruster system was measured with three-wire torsion pendulum thrust measurement system and the measurement uncertainty was also studied, thereby judging the credibility of the experimental measurements. The results show that three-wire torsion pendulum thrust measurement system can measure thrust not less than 3mN under the existing experimental conditions with the relative uncertainty of 14%. Within the measuring range of three-wire torsion pendulum thrust measurement system, the independent microwave thruster propulsion device did not detect significant thrust. Measurement results fluctuate within 0.7mN range under the conditions 230W microwave power output and the relative uncertainty is greater than 80%.

1 - Was this with an 'onboard' power source?

2 - 'relative uncertainty is greater than 80%' AND 'did not detect significant thrust.'  If there was an 'onboard' power source, perhaps this is evidence the EM Drive does not work?  Or does that uncertainty leave room for some sort of 'reduced thrust' (roughly photon equivalent) effect?

3 - 2014 paper.  Perhaps these results are the reason for the apparent abandonment of Chinese EM Drive research?

I just finished reading a very poorly translated version of the PDF. Here is what I gather.

1. The experiment was performed two ways: with a battery and with power provided externally.

2. I did not see any mention of dialectric inserts

3. Their conclusion is that "heat distortion power line has caused a very large dry interference" and "thus thrust measurement result is mainly produced by dry wire connection interferences."

EDIT: Just saw this from /u/pomezi: "It should be noted, however, that the measurement system was only capable of measuring performance greater than 3mN. This is much more than the results claimed by Eagleworks and Tajmar."

Thank you. These points (less the dialectic part) were also what I summarized in Wikipedia. One other important point is that they nullified the 720mN 2008 result.
Thank you for posting these news which are a great triumph for Science ! These news are among the biggest news on the EM Drive thread since thread 1.

This must be a headache for theories like Shawyer's and McCulloch's that used Yang's results as support for their theories! How do their theories reconcile this nullification of results?

These news also validate the DIY experiment of RFPlumber, who obtained insignificant force/InputPower that did not match the extravagant claims of Yang and Shawyer.

1) This is now at least the second time that institutional R&D scientists have nullified their prior tentative claims regarding propellant-less thrusters:

1a) the first ones were Brito, Marini and Galian in Argentina that nullified the decades-long R&D work of Brito on his type of Mach Lorentz Thruster, supported by various institutions including the US Air Force, using a battery-powered torsional pendulum to nullify the previous results

1b) now Yang has nullified her prior results which claimed the highest force/InputPower of any microwave resonant cavity: 1 Newton/kiloWatt

this shows that those that wrote that institutional R&D scientists are not likely to nullify their prior results are wrong.  Institutional R&D scientists are motivated by Science and not by "beliefs" or promotion of private company goals.  They are not motivated by fulfilling dreams. Scientists are motivated in finding the truth.

2) The nullification of Yang's prior results pretty much nullifies the claims of Shawyer as well. She used the same mode shapes as Shawyer, was coached by Shawyer and quoted Shawyer's "theories" in her works.  Shawyer repeatedly quoted her claimed results as support for his own claims.  Although Shawyer has been testing the EM Drive longer than anyone else, his tests stand out for: Shawyer never reporting a single test in a vacuum chamber, Shawyer never reporting a single test in a torsional pendulum, Shawyer never reporting a single test powered by a battery self-integrated in the moving device.

3) There is still a small window opened: the fact that NASA reported that without a polymer insert, NASA was not able to achieve significant force/InputPower even when using over 10 times higher power. And the fact that the Aachen Germany, Hackaway team is presently reporting "good" results using a polymer insert in a  battery-powered tiny EM Drive. (*)

4) Given Yang's results, it is clear that, for any EM Drive test to gain credibility, it should be performed in:

4a) torsional pendulum (teeter-totters and scales can be shown to be flawed devices, as known in Aerospace R&D of over 50 years of testing in micro-thrusters)

4b) self-integrated power source (i.e. battery powered) in the same moving platform (having the power come from a stationary source is fundamentally flawed from a conservation of energy viewpoint).  No power cables going to an external power source !

4c) partial vacuum (to eliminate thermal convection, as it has been known since the 19th century that all radiation pressure tests under ambient conditions are plagued by the effect of thermal convection).






(*) As repeatedly stated, people should not be confused by reports that NASA "MAY" ("may" in capital letters) have obtained some thrust without a polymer insert without taking into account:

*a) the figure of merit for EM Drive's is the force/Input power.  The numerical value of different test results should be compared on the basis of the force/InputPower achieved (and not based on "force" without taking into account the power input)

*b) the statistical significance of any value of force/inputPower

*c) the testing apparatus: tests performed at NASA's teeter-totter should not be compared to tests performed on NASA's torsional pendulum.  Experimental values should be compared in the same testing device, preferably the torsional pendulum, as is known in Aerospace R&D of micro-thrusters, for over 50 years, that the torsional pendulum is the best type of measurement and the teeter-totter is among the worst.

*d) as I have shown elsewhere, the function of the polymer insert in NASA's EM Drive was never to be a dielectric, due to its electric permittivity.  NASA obtained insignificant force/InputPower when using inorganic dielectrics with relative electric permittivity ~38 as used by Shawyer.  Such dielectrics reduce the Q.  Instead NASA used polymers with relative electric permittivity ~2 closer to the value of air or vacuum ~1.  The polymer insert in NASA'and Aachen teams EM Drives should not be described as "dielectrics". That is a false narrative.  Instead their function may be justified on the basis of Woodward's theory, of Dr. White's QV theory.  It cannot be justified on its dielectric properties. Since it may be justified based on its piezoresistive properties or its piezoelectric and electrostrictive properties, instead of being described as a dielectric it should be described as piezoresistive, piezoelectric or electrostrictive material.

Yhis is very interesting.  I thought Yang was retired.  I wonder what exactly is a "very large dry interference".   If this new result is true and the translation is correct it still leaves Shawyers' positive results.   I believe the Traveller also stated he measured significant thrust.  Has there been any more data or photos from that experiment?

Offline Rodal

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...
Yhis is very interesting.  I thought Yang was retired.  I wonder what exactly is a "very large dry interference".   If this new result is true and the translation is correct it still leaves Shawyers' positive results.   I believe the Traveller also stated he measured significant thrust.  Has there been any more data or photos from that experiment?
Yang performed the nullification of her previous results using a torsional pendulum for her first time.  She had never reported tests in a torsional pendulum prior to this nullification.  She had previously used an inverted beam bending pendulum (using beam stiffness).   Brito Marini and Galian had previously shown the problem with the inverted beam bending pendulum previously used by Yang.

Prof. Martinez-Sanchez at MIT (an authority on micro-thusting research for decades) has also shown the problem with such inverted beam bending instruments.

To me one of the most surprising things in the EM Drive saga, is that although it has been known in the Aerospace R&D field for over 50 years of research in micro-thrusters that the instrument of choice is the torsional pendulum, and that the instrument of choice in measurements of the gravitational constant G has been the torsional pendulum, (for hundreds of years, since Cavendish), that it took this long (several years) for Prof. Yang to conduct a test in a torsional pendulum, and that Shawyer has never reported a single test in a torsional pendulum.  Also why did Prof. Tajmar bothered to conduct tests in a teeter-totter? Was it to show that Shawyer's results were due to using a wrong instrument? (If so Tajmar should have made this clear, as people are not clear as to what is the main reason that his tests in a torsional pendulum in a partial vacuum showed much lower results than the tests at ambient conditions in a teeter-totter: how much was the reduction in performance due to the partial vacuum and how much was it due to the use of a torsional pendulum instead of a teeter-totter?)

Concerning TT:

1) he has never reported photographs or output data from the claimed experimental results
2) his tests were reported to be on a scale, not on a torsional pendulum

Given the nullification of Yang's prior results by using a torsional pendulum for her first time, and given the nullification of Brito's results by using a torsional pendulum, and by the fact that if you go to a major university Aerospace department and you ask what is the instrument to use to measure micro-thrust they will respond a torsional pendulum, serious discussion of test results should involve torsional pendulum results.

Nullification of experiments using other instruments, by both Brito and Yang has been performed using torsional pendulums.  Therefore only tests in torsional pendulums can gain credibility.

Tests in other instruments ignore the nullification results of Yang and of Brito. 

The other important thing is conservation of energy.  Which is tied to conservation of momentum, but thanks to Prof. Frobnicat it is easier to show what a huge problem it represents.

Hence external power supplies are a complete and utter no-no in these experiments.

The title of these threads are EM Drive Developments - related to space flight applications

In space you don't get to have an external power source with a cable going from the Earth to your satellite


Experiments that are run with external stationary power sources are most questionable.

They ignore the fact that the power source is external.
« Last Edit: 05/01/2016 03:18 pm by Rodal »

Offline oyzw

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Professor Yang using this method

Offline Rodal

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For comparison this is the method used by Brito, Marini and Galian to nullify his decade-long R&D results on propellant-less thrusters:

* torsional pendulum (also Yang used torsional pendulum)

*self-integrated power-source, no cables to the outside (battery-powered)
« Last Edit: 05/01/2016 03:06 pm by Rodal »

Offline rfmwguy

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Very pleased to see this paper and agree that it demonstrates scientific methodology. Wish we had more attempts elsewhere by institutions to add to this one paper. It brings up questions I'll need some help with.

1) Bar was set at 3mN min resolution. Seems rather high. Is it because of a larger mass needing to be rotated (integrated power supply)?

2) Does conclusion point to thermal expansion of power leads in first test or Mr Li's Lorentz force?

3) Was the same device hardware tested on both occasions?

4) What force in n/kw does this falsify?

5) What is the minimum force in n/kw was this new test stand capable of measuring?

Offline Rodal

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As I have been saying for several threads: NASA's 2014 report ended with a sentence that John Hopkins was interested in cooperating with NASA to use a Cavendish type torsional pendulum to replicate NASA's results.

American Institute of Aeronautics and Astronautics
50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference
July 28-30, 2014, Cleveland, OH

Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
David A. Brady, Harold G. White, Paul March, James T. Lawrence, and Frank J. Davies

Quote
The Johns Hopkins University Applied Physics Laboratory has also expressed an interest in performing a Cavendish Balance style test with the IV&V shipset.

I hope that NASA is now conducting a self-integrated, battery-powered, test with a torsional pendulum under partial-vacuum.

This is the only kind of test that would give credibility to the EM Drive, particularly given Yang's latest published results.  Hope that is what NASA is working on!
« Last Edit: 05/01/2016 03:48 pm by Rodal »

Offline Tellmeagain

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Very pleased to see this paper and agree that it demonstrates scientific methodology. Wish we had more attempts elsewhere by institutions to add to this one paper. It brings up questions I'll need some help with.

1) Bar was set at 3mN min resolution. Seems rather high. Is it because of a larger mass needing to be rotated (integrated power supply)?

2) Does conclusion point to thermal expansion of power leads in first test or Mr Li's Lorentz force?

3) Was the same device hardware tested on both occasions?

4) What force in n/kw does this falsify?

5) What is the minimum force in n/kw was this new test stand capable of measuring?

1. Probably because of the 3-wire method. single wire method should provide much better resolution.
2. They pointed at thermal expansion of power leads. Note that the paper was submitted in 2014 and they did not know Mr Li's work by then.
3. From the figures, yes, but batteries were removed in the second test.
4. They said in the paper that the 2008 results suffered heat expansion of the flexible waveguide.
5. 3mN.

Offline Rodal

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Very pleased to see this paper and agree that it demonstrates scientific methodology. Wish we had more attempts elsewhere by institutions to add to this one paper. It brings up questions I'll need some help with.

1) Bar was set at 3mN min resolution. Seems rather high. Is it because of a larger mass needing to be rotated (integrated power supply)?

2) Does conclusion point to thermal expansion of power leads in first test or Mr Li's Lorentz force?

3) Was the same device hardware tested on both occasions?

4) What force in n/kw does this falsify?

5) What is the minimum force in n/kw was this new test stand capable of measuring?

1 and 4:
You must take into account the statistical significance when discussing resolution.  She states:

Quote
can measure thrust not less than 3mN under the existing experimental conditions with the relative uncertainty of 14%.

Quote
Measurement results fluctuate within 0.7mN range under the conditions 230Wmicrowave power output,and the relative uncertainty is greater than 80%.

so:  uncertainty at 14% --> 3 mN
      uncertainty at 80% --> 0.7mN

I presume

      uncertainty at 0% --> INFINITE force
     INFINITE uncertainty --> zero force


In other words, if one demands zero uncertainty, then one can never conclude anything in any experimental measurement, as all experimental measurements involve uncertainty, and it cannot be ignored when quoting results.

The more uncertainty you are willing to consider, the lower the force.
There is nothing "standard" or magic about the 14% uncertainty for the 3 mN, it is an arbitrary amount of uncertainty, and by experimental standards in Physics, it is a fairly high degree of uncertainty, probably due to her sample size (the sample size for EM Drive experiments is horribly small, and most EM Drive experimenters have a smaller number of experiments than Yang)


I don't know what statistical significance methods she is considering but I would not be surprised if she assumes (without experimental basis) Gaussian statistics, as that would be the easiest thing to do, as follows:

     

3.

Yang only used a torsional pendulum for these latest tests.  Yang had never reported tests in a torsional wire pendulum prior to this latest nullification results
« Last Edit: 05/01/2016 04:27 pm by Rodal »

Offline Tellmeagain

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Yhis is very interesting.  I thought Yang was retired.  I wonder what exactly is a "very large dry interference".   If this new result is true and the translation is correct it still leaves Shawyers' positive results.   I believe the Traveller also stated he measured significant thrust.  Has there been any more data or photos from that experiment?

There is no "dry interference", but "interference" without "dry". The word "dry" is caused by bad translation.

Offline rfmwguy

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Very pleased to see this paper and agree that it demonstrates scientific methodology. Wish we had more attempts elsewhere by institutions to add to this one paper. It brings up questions I'll need some help with.

1) Bar was set at 3mN min resolution. Seems rather high. Is it because of a larger mass needing to be rotated (integrated power supply)?

2) Does conclusion point to thermal expansion of power leads in first test or Mr Li's Lorentz force?

3) Was the same device hardware tested on both occasions?

4) What force in n/kw does this falsify?

5) What is the minimum force in n/kw was this new test stand capable of measuring?

1. Probably because of the 3-wire method. single wire method should provide much better resolution.
2. They pointed at thermal expansion of power leads. Note that the paper was submitted in 2014 and they did not know Mr Li's work by then.
3. From the figures, yes, but batteries were removed in the second test.
4. They said in the paper that the 2008 results suffered heat expansion of the flexible waveguide.
5. 3mN.
Thank you sir. Ahh, I forgot rf source and power supply was not mounted on yangs frustum. So mine will be once again be on frustum so no feedline issues. I will still need to mitigate lorentz with your help. In one of my videos, I measured almost no heat rise on twisted power leads on the beam. Yes, I think you are correct, a 3 wire system was needed for a higher weight system. I should still be able to use single wire.

Uncertainty is akin to test equipment innaccuracies summed up. In my simple language, the greater the weight, the greater the minimum accuracy...i.e. 14% or perhaps +/- 7% accuracy which is a reasonable number in most rf measurement tests for general purpose applications.

Still, this is a valuable paper imho. Much will be learned and hope we see a proper english translation.

Offline Rodal

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Very pleased to see this paper and agree that it demonstrates scientific methodology. Wish we had more attempts elsewhere by institutions to add to this one paper. It brings up questions I'll need some help with.

1) Bar was set at 3mN min resolution. Seems rather high. Is it because of a larger mass needing to be rotated (integrated power supply)?

2) Does conclusion point to thermal expansion of power leads in first test or Mr Li's Lorentz force?

3) Was the same device hardware tested on both occasions?

4) What force in n/kw does this falsify?

5) What is the minimum force in n/kw was this new test stand capable of measuring?

1. Probably because of the 3-wire method. single wire method should provide much better resolution.
2. They pointed at thermal expansion of power leads. Note that the paper was submitted in 2014 and they did not know Mr Li's work by then.
3. From the figures, yes, but batteries were removed in the second test.
4. They said in the paper that the 2008 results suffered heat expansion of the flexible waveguide.
5. 3mN.
Thank you sir. Ahh, I forgot rf source and power supply was not mounted on yangs frustum. So mine will be once again be on frustum so no feedline issues. I will still need to mitigate lorentz with your help. In one of my videos, I measured almost no heat rise on twisted power leads on the beam. Yes, I think you are correct, a 3 wire system was needed for a higher weight system. I should still be able to use single wire.

Uncertainty is akin to test equipment innaccuracies summed up. In my simple language, the greater the weight, the greater the minimum accuracy...i.e. 14% or perhaps +/- 7% accuracy which is a reasonable number in most rf measurement tests for general purpose applications.

Still, this is a valuable paper imho. Much will be learned and hope we see a proper english translation.

The uncertainty that Prof. Yang is discussing is instead, tied to the statistical sample size: the number of experiments carried out.

The number of experiments carried out by EM Drive experimenters up to now is horribly small.  That's why I said that it is misleading to use statistical methods for such a miniscule number of experiments.

If EM Drive experimenters want to strengthen the confidence on their results, they must increase the number of experiments.

See the graph I posted above showing the relationship of number of experiments to margin of error.

https://en.wikipedia.org/wiki/Margin_of_error

https://en.wikipedia.org/wiki/Observational_error

PS: having said that, it appears that the number of experiments carried out by Yang exceeds the number of experiments carried out by other researchers, as she is the only one quoting % uncertainty figures
« Last Edit: 05/01/2016 04:44 pm by Rodal »

Offline Tellmeagain

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Thank you sir. Ahh, I forgot rf source and power supply was not mounted on yangs frustum. So mine will be once again be on frustum so no feedline issues. I will still need to mitigate lorentz with your help. In one of my videos, I measured almost no heat rise on twisted power leads on the beam. Yes, I think you are correct, a 3 wire system was needed for a higher weight system. I should still be able to use single wire.

Uncertainty is akin to test equipment innaccuracies summed up. In my simple language, the greater the weight, the greater the minimum accuracy...i.e. 14% or perhaps +/- 7% accuracy which is a reasonable number in most rf measurement tests for general purpose applications.

Still, this is a valuable paper imho. Much will be learned and hope we see a proper english translation.

You are welcome. I will be happy to review your settings. The 3 wire system they used was not a good choice, apparently. If it was because of the weight, they should have used a thicker single wire, or 3 wires twisted together. 

Offline Rodal

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Thank you sir. Ahh, I forgot rf source and power supply was not mounted on yangs frustum. So mine will be once again be on frustum so no feedline issues. I will still need to mitigate lorentz with your help. In one of my videos, I measured almost no heat rise on twisted power leads on the beam. Yes, I think you are correct, a 3 wire system was needed for a higher weight system. I should still be able to use single wire.

Uncertainty is akin to test equipment innaccuracies summed up. In my simple language, the greater the weight, the greater the minimum accuracy...i.e. 14% or perhaps +/- 7% accuracy which is a reasonable number in most rf measurement tests for general purpose applications.

Still, this is a valuable paper imho. Much will be learned and hope we see a proper english translation.

You are welcome. I will be happy to review your settings. The 3 wire system they used was not a good choice, apparently. If it was because of the weight, they should have used a thicker single wire, or 3 wires twisted together.
Anything you do in the experiment (for example regarding the comment about 3 wires) will not address the statistical sample size problem.  If you perform only a few experiments then you have a small statistical sample, therefore you will not be able to improve the statistical confidence, as your statistical significance will be limited by your small number of experiments.

As an example in the extreme, to make the point, somebody may claim to have a perfect experiment, but if it was carried out only once, you cannot use statistics  :)

There are two considerations here:

1) Improve your experiment as much as possible (use a torsional pendulum, single wire, self-powered by batteries, in a partial vacuum, etc.)

and a separate consideration:

2) consider experimental uncertainty and hence must conduct enough experiments as to get a reasonable statistical sample size to be able to plot a histogram, ascertain the statistical distribution, margin of error, etc.

EM Drive experiments suffer on both viewpoints.

The second one (statistical sample size) is horrible, which is not surprising given the early stage and controversial aspect of what is being researched and the lack of funds available for its study.

Apparently Prof. Yang has conducted a larger number of experiments than most other experimenters, given her quoted uncertainty.

DIY experimenters have much fewer number of experiments. They are not in the same league.
« Last Edit: 05/01/2016 05:29 pm by Rodal »

Offline Tellmeagain

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Anything you do in the experiment (for example regarding the comment about 3 wires) will not address the statistical sample size problem.  If you perform only a few experiments then you have a small statistical sample, therefore you will not be able to improve the statistical confidence, as your statistical significance will be limited by your small number of experiments.

As an example in the extreme, to make the point, somebody may claim to have a perfect experiment, but if it was carried out only once, you cannot use statistics  :)

There are two different viewpoints here:

1) Improve your experiment as much as possible (use a torsional pendulum, single wire, self-powered by batteries, in a partial vacuum, etc.)

and a separate point:

2) consider inherent uncertainty and hence must conduct enough experiments as to have a reasonable statistical sample size

You are right. Yang et.al. carried out 20 experiments, according to figure 18 a and b.

Offline Rodal

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EMDrive talk on "new age" science show starts about 29 minutes in. NSF and Chris Bergin get a plug @ about 33 minutes in.


I'm very involved with TMRO and have been a guest 6 times.  I was at Hershey Park on Saturday.  I'm quite embarrassed for them, this show was not up to their usual standard - they didn't even pronounce 'magnetron' correctly.

It's not really 'new age' science, it's mostly space and space news (where they do have expertise).

I am, in fact, here on the forum because they asked me to do a short video on the EMDrive last August.  It's taken me until about now to be able to understand most of the physics discussed here :)  I'm going to respond to their show, probably with a short video which I hope will get played next week...
Thanks Emory...new age as in younger, more hip science shows I guess is what I was thinking  8)

Great! Feel free to download any of my youtube clips if you need some filler. Here they are:

https://www.youtube.com/channel/UCm54FS3u2aDeutnMsV0cITg/videos

Royalty free as well ::) Give us a peek at the vid if you get the chance. - Dave

This latest paper by Prof. Yang nullifying her previous results present a great opportunity for you to announce in your appearance in this upcoming program at TMRO!

As these news have not yet been publicized in the media

These are the biggest news on EM Drive in several years !
« Last Edit: 05/01/2016 05:24 pm by Rodal »

Offline Eusa

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Quote from: Rodal
I hope that NASA is now conducting a self-integrated, battery-powered, test with a torsional pendulum under partial-vacuum.

This is the only kind of test that would give credibility to the EM Drive, particularly given Yang's latest published results.  Hope that is what NASA is working on!
I hope that with battery there were DC-inverter for excluding current-dependences...

Offline Rodal

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Anything you do in the experiment (for example regarding the comment about 3 wires) will not address the statistical sample size problem.  If you perform only a few experiments then you have a small statistical sample, therefore you will not be able to improve the statistical confidence, as your statistical significance will be limited by your small number of experiments.

As an example in the extreme, to make the point, somebody may claim to have a perfect experiment, but if it was carried out only once, you cannot use statistics  :)

There are two different viewpoints here:

1) Improve your experiment as much as possible (use a torsional pendulum, single wire, self-powered by batteries, in a partial vacuum, etc.)

and a separate point:

2) consider inherent uncertainty and hence must conduct enough experiments as to have a reasonable statistical sample size

You are right. Yang et.al. carried out 20 experiments, according to figure 18 a and b.

Mmmm (as a rapid estimate without doing any math  ;) )


For a 95% confidence level (which means that there is only a 5% chance of your sample results differing from the true population average), a good estimate of the margin of error (or confidence interval) is given by 1/√N, where N is the number of experiments or sample size (Niles, 2006). http://www.robertniles.com/stats/margin.shtml

A 14% margin of error (at 95% confidence) implies 50 experiments rather than 20.

1/√50 = 0.14

20 experiments give a 22% margin of error rather than 14%.

1/√20 = 0.22

So this means that she used less than 95% confidence level...
« Last Edit: 05/01/2016 06:00 pm by Rodal »

Offline SeeShells

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EMDrive talk on "new age" science show starts about 29 minutes in. NSF and Chris Bergin get a plug @ about 33 minutes in.


I'm very involved with TMRO and have been a guest 6 times.  I was at Hershey Park on Saturday.  I'm quite embarrassed for them, this show was not up to their usual standard - they didn't even pronounce 'magnetron' correctly.

It's not really 'new age' science, it's mostly space and space news (where they do have expertise).

I am, in fact, here on the forum because they asked me to do a short video on the EMDrive last August.  It's taken me until about now to be able to understand most of the physics discussed here :)  I'm going to respond to their show, probably with a short video which I hope will get played next week...
Thanks Emory...new age as in younger, more hip science shows I guess is what I was thinking  8)

Great! Feel free to download any of my youtube clips if you need some filler. Here they are:

https://www.youtube.com/channel/UCm54FS3u2aDeutnMsV0cITg/videos

Royalty free as well ::) Give us a peek at the vid if you get the chance. - Dave

This latest paper by Prof. Yang nullifying her previous results present a great opportunity for you to announce in your appearance in this upcoming program at TMRO!

As these news have not yet been publicized in the media

These are the biggest news on EM Drive in several years !

How can you write such a definitive statement relating it to fact with the Chinese null test when you didn't give as much credence to the positive thrust events?

I believe we need to temper our enthusiasm in both tests where they showed thrusts and when they did not. It's quite hard to verify that this was indeed her results and we need to be as skeptical of the positive tests as we were treat the negative the same way. Truly more independent data is needed.





I'm going to say that this isn't a definitive test because of unknowns until more verifiable data is forthcoming.

Offline Rodal

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EMDrive talk on "new age" science show starts about 29 minutes in. NSF and Chris Bergin get a plug @ about 33 minutes in.


I'm very involved with TMRO and have been a guest 6 times.  I was at Hershey Park on Saturday.  I'm quite embarrassed for them, this show was not up to their usual standard - they didn't even pronounce 'magnetron' correctly.

It's not really 'new age' science, it's mostly space and space news (where they do have expertise).

I am, in fact, here on the forum because they asked me to do a short video on the EMDrive last August.  It's taken me until about now to be able to understand most of the physics discussed here :)  I'm going to respond to their show, probably with a short video which I hope will get played next week...
Thanks Emory...new age as in younger, more hip science shows I guess is what I was thinking  8)

Great! Feel free to download any of my youtube clips if you need some filler. Here they are:

https://www.youtube.com/channel/UCm54FS3u2aDeutnMsV0cITg/videos

Royalty free as well ::) Give us a peek at the vid if you get the chance. - Dave

This latest paper by Prof. Yang nullifying her previous results present a great opportunity for you to announce in your appearance in this upcoming program at TMRO!

As these news have not yet been publicized in the media

These are the biggest news on EM Drive in several years !

How can you write such a definitive statement relating it to fact with the Chinese null test when you didn't give as much credence to the positive thrust events?

I believe we need to temper our enthusiasm in both tests where they showed thrusts and when they did not. It's quite hard to verify that this was indeed her results and we need to be as skeptical of the positive tests as we were treat the negative the same way. Truly more independent data is needed.





I'm going to say that this isn't a definitive test because of unknowns until more verifiable data is forthcoming.

I thought that I justified this in my prior posts. But here it goes again:

1) Second time, after Brito, Marini and Galian that a researcher nullifies their previous claims.  Done by using torsional pendulum and self-powered battery-operated.  It shows that scientists can and will publish experiments nullifying their previous results because scientists are interested in finding what is the truth. Having Prof. Yang publish a paper that nullifies her life work is undeniably, objectively, powerful.

2) All tests performed in teeter-totters and scales, and moreover having a power cord for energy supply have to be disregarded, in light of these results.   For more than 50 years it has been known in Aerospace R&D that the instrument of choice for micro-thrust experiments is the torsional pendulum.  For centuries it has been known that the sensitive instrument to measure G is the torsional pendulum. 

3) Since the 19th century it has been known that radiation pressure experiments are contaminated by thermal convection.

4) One doesn't get to run a power cord from the Earth to a spacecraft in space.  Tests that supply power from a stationary source by a cord to a moving EM Drive (instead of using self-integrated batteries) are questionable.   Conservation laws mean that the power source and its cables must be taken into account, and one does not get to ignore them from consideration and hide them under a curtain (as in the Wizard in the Wizard of Oz). The cables not only because of their electromagnetic effects but also because of their thermal expansion, as discussed by TellMeAgain above.
« Last Edit: 05/01/2016 06:38 pm by Rodal »

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