Author Topic: EM Drive Developments Thread 1  (Read 781364 times)

Offline Rodal

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Re: EM Drive Developments
« Reply #1600 on: 10/06/2014 02:34 PM »
http://arxiv.org/pdf/1302.2775v1.pdf

This paper needs accelerated peer review.

Quote from: McCulloch's paper
Assuming a large acceleration, ie: a terrestrial one, we can neglect this MiHsC term...

What is a "terrestrial acceleration"?

I would like to read this:

Gine, J., 2012. The holographic scenario, the modified inertia and the dynamics
of the universe. Mod. Phys. Lett. A. Vol. 27, No. 34, 1250208.

By terrestrial acceleration I meant something typical of a mutual acceleration on Earth, eg: 9.8 m/s^2.

A very warm welcome to this forum, Prof. McCulloch  :)

Prof. McCulloch, your estimations of the Shawyer and NASA Eagleworks results are the ones that come closest to the experimental results.  What is particularly interesting is that your estimations do so with a bare minimum of parameters: just using the dimensions, Q factor, power input, and frequency.

Offline aceshigh

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Re: EM Drive Developments
« Reply #1601 on: 10/06/2014 02:35 PM »
... i was like message boy ...

You still don't get it, do ya?  Take a weekend trip to AZ, and get a sense of Yuma.

no, I dont get it, nor do I get this last message. Btw, I was not re-complaining about posting stuff from here there, and post from there here, I was merely pointing out that I had already made it public that I was posting at Talk Polywell forums.

Offline Mulletron

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Re: EM Drive Developments
« Reply #1602 on: 10/06/2014 02:38 PM »
there is only one electron in the universe

And it's mine!



The Great Feynman would say that.
Challenge your preconceptions, or they will challenge you. - Velik

Offline Mulletron

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Re: EM Drive Developments
« Reply #1603 on: 10/06/2014 02:40 PM »
how I picture the most optimal shape of the apparatus...

Your pic doesn't look like a 45 degree cone, and what are the dimensions?  How about energy going in, and acceleration in the pointy direction?

Solo chiedendo.

Your pic (  http://forum.nasaspaceflight.com/index.php?topic=29276.msg1266842#msg1266842  ) doesn't look like a 45 degree cone either.  You give me the material, and I'm on a roll today.  Solo dicendo  :)

There is no way to say that with an arbitrary perspective, nevertheless. The design intent is a 45 degree light cone. Looking for cad errors isn't the important thing here.
Challenge your preconceptions, or they will challenge you. - Velik

Online aero

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Re: EM Drive Developments
« Reply #1604 on: 10/06/2014 02:43 PM »
Guys, hold on here. While I was thinking of making a post, ordering my thoughts so to speak, five new posts appeared. I closed my browser, opened and read the posts, then started to reply but there are more new posts.

I am going to wait until some of you get to work, then I'll post on topic.
Retired, working interesting problems

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1605 on: 10/06/2014 02:53 PM »
how I picture the most optimal shape of the apparatus...

Your pic doesn't look like a 45 degree cone, and what are the dimensions?  How about energy going in, and acceleration in the pointy direction?

Solo chiedendo.

Your pic (  http://forum.nasaspaceflight.com/index.php?topic=29276.msg1266842#msg1266842  ) doesn't look like a 45 degree cone either.  You give me the material, and I'm on a roll today.  Solo dicendo  :)

There is no way to say that with an arbitrary perspective, nevertheless. The design intent is a 45 degree light cone. Looking for cad errors isn't the important thing here.

Don't get me wrong.  I'm not "looking" for CAD errors.  And I get that about perspective.  Still, it looked like a 60 degree cone. 

As you were.
« Last Edit: 10/06/2014 07:33 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline Mulletron

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Re: EM Drive Developments
« Reply #1606 on: 10/06/2014 03:26 PM »
how I picture the most optimal shape of the apparatus...

Your pic doesn't look like a 45 degree cone, and what are the dimensions?  How about energy going in, and acceleration in the pointy direction?

Solo chiedendo.

Your pic (  http://forum.nasaspaceflight.com/index.php?topic=29276.msg1266842#msg1266842  ) doesn't look like a 45 degree cone either.  You give me the material, and I'm on a roll today.  Solo dicendo  :)

There is no way to say that with an arbitrary perspective, nevertheless. The design intent is a 45 degree light cone. Looking for cad errors isn't the important thing here.

Don't get me wrong.  I'm not "looking" for CD errors.  And I get that about perspective.  Still, it looked like a 60 degree cone. 

As you were.

Ok laptop screen is widescreen but the pic is square, jeez. There is a difference between qualitative and quantitative. It was a quick and dirty pic to show a concept. The quantities describing it are verbose in the text. Anyway I hope I got the underlying interpretation wrong, so I can fix it and learn something new, further making progress to a real path to the stars.

Edit: Okay I made a cad error. I rushed it. I done better this time.
I know why I screwed up the drawing. It was because I amateurishly started with the radius of the circle. I should have started with the most fundamental thing in physics, which is the speed of light, which informs the light cone, then derived the radius of the circle. I didn't run a real angular dimension check in cad to verify correctness and ended up with a stretched out test article. Causality flows from the pointy end to the round end!

Edit: I even screwed it up again. I haven't touched autocad in a very long time and even simple tasks apparently are hard now for me. Pic replaced with correct one.

Given a sphere filled with homogenous radiation which is pushing against everything else equally and with the absence of other forces, another smaller sphere inserted inside the larger sphere would not be biased in any particular direction. Now replace the internal sphere with the cone with half sphere base, I predict the cone would be biased toward the half spherical end. The surface area of the half sphere with and arbitrarily picked r=1.5 is 14.14, while the surface area of the cone with height=3.695 is 18.79. In terms of classical mechanics, the imbalance would create a bias toward the round end. Casimir forces are more complex than this, so this is a rough model.

« Last Edit: 10/06/2014 10:25 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Rodal

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Re: EM Drive Developments
« Reply #1607 on: 10/06/2014 03:31 PM »
Okay, so they flipped the entire test article.  I thought you were saying they had reoriented the dielectric inside the test article.

Flipping the test article does work for isolating any coupling from the power leads, which you had previously been concerned about.
The coupling is very concerning because the Eagleworks report admits that the effect of the magnetic dampening interacting with the field of the power cable gives a signal of about  ~25% of their measurements.  It affects their baseline in an erratic manner and they try to subtract its effect as a linear influence (therefore not taking into account any nonlinearity).  Since the Eagleworks data is also very nonlinear (for example the case where increasing the input power by a factor or 6 results in a decrease of the measured thrust of 10%) it is useful to further clarify this coupling effect.

Now, the magnetic damper is located downstream in the vacuum chamber, behind the inverted pendulum beam, while the tested article is in front, upstream in the vacuum chamber.

QUESTION: Ron, (if I understood correctly your statement <<Flipping the test article does work for isolating any coupling from the power leads>>), why do you think that flipping the test article would eliminate the effect of the magnetic damper with the power lead and the tested drive?  Wouldn't be the case that if there is coupling between the magnetic field from the damper, the power cable, and the electromagnetic fields in the tested article (both magnetic and electric fields inside it), that flipping the test article would still produce an artifact, now in the opposite direction?  (as also suggested in an example drawing by @frobnicat a couple of pages back)?
« Last Edit: 10/06/2014 03:59 PM by Rodal »

Offline DIYFAN

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Re: EM Drive Developments
« Reply #1608 on: 10/06/2014 04:06 PM »
Lurker and former engineer here making first post.  I'm intrigued by the theoretical outlays here, but wondering how many among us are potential DIY experimentalists?  I believe that sufficient information is now accessible to the public to independently replicate and confirm this technology widely.  I envision something along the lines of the DIY drone developers and their enthusiasm for advancing that field, with a rapid feedback loop and dispersion of information.

For starters, here is the latest published patent application:
http://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=0&ND=3&adjacent=true&locale=en_EP&FT=D&date=20130206&CC=GB&NR=2493361A&KC=A

YBCO superconducting film to line the inner cavity:
http://www.mtixtl.com/YBCO100nm-film-SrTiO3-101005.aspx

3GHz+ signal generators:
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR5.TRC1.A0.H0.X3ghz+signal+generator&_nkw=3ghz+signal+generator&_sacat=0

Microwave power amplifiers:
http://www.ebay.com/sch/i.html?_odkw=microwave+signal+amplifier&_from=R40|R40|R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xmicrowave+power+amplifier&_nkw=microwave+power+amplifier&_sacat=0

The architectural design, materials, and concepts are described in a fairly straight-forward manner in the patent publication.  YBCO film is superconducting above liquid nitrogen boiling point.  I estimate that an experiment could be put together for less than $2000 of parts.  Of course, the requisite time and knowledge for carrying it out would need to be conducted, probably with no compensation.  Who among us are willing and able?  Is there a Steve Jobs of propellentless devices among these ranks?  My thought is that to advance this tech quickly, technically capable and independent people, not beholden too much to dogma or larger institutions, are going to have to run with it and spread it as far and wide as possible.

Trip to Home Depot in order? Like it.

Hope Depot is a man's best friend.  :)

For the cavity itself, metal 3d printing is now ubiquitous and affordable.

http://gpiprototype.com/services/metal-3d-printing.html
https://www.solidconcepts.com/technologies/direct-metal-laser-sintering-dmls/?gclid=CMCy2rWzmMECFQqCfgod3A4AXw
(and many others)

A simple CAD design and a submission to a 3d printing company can yield a well-formed prototype cavity within 1-2 weeks.  The prototype can be formed of a variety of metals.  The prototype could be tested in a non-superconducting configuration first to get a baseline.  Then, the inner portion of the cavity could be lined with YBCO film, cooled to liquid nitrogen temperatures, and tested in a superconducting configuration.

It even appears that some 3d printers are capable of printing using superconducting materials:
http://www.tamuk.edu/engineering/departments/mien/3D%20Printers/index.html



Offline Ron Stahl

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Re: EM Drive Developments
« Reply #1609 on: 10/06/2014 04:07 PM »
why do you think that flipping the test article would eliminate the effect of the magnetic damper with the power lead and the tested drive? 
Paul helped design the Eagle balance based upon lessons learned with Woodward's ARC Lite balance.  That balance was specifically designed so one could physically reorient the thruster without reorienting the power leads to it, so that if they were coupling, that coupling would not also flip--hence isolating the spurious from the actual thrust.  I can only presume Paul kept that protocol.  I haven't seen the detailed explanations of the Eagle balance that have been so public with Woodward's work, but Paul knows the value of that particular practice.

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1610 on: 10/06/2014 04:24 PM »
Taking a shot at an "axion condensate dark matter" energy to force calculation.

So theory and experiment both give a reduction in "sound speed" in a dilute condensate of ~ 10^-6.  So, let's say s = < 300 m/sec, given the assumption that the "axions" "interact" via gravity at c.

Using a rough experimental result of 10W => 50 micronewtons for comparison.

At 300 m/sec, I need to generate 2.5 X 10^22 phonons/sec at a power of 1.5 X 10-2 watts to generate that 50 micronewtons.

So 15 milliwatts out of 10 watts => 0.15%  (pretty high)

Edit +10^22 and phonons not photons
« Last Edit: 10/06/2014 04:27 PM by Notsosureofit »

Offline Rodal

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Re: EM Drive Developments
« Reply #1611 on: 10/06/2014 04:39 PM »
why do you think that flipping the test article would eliminate the effect of the magnetic damper with the power lead and the tested drive? 
Paul helped design the Eagle balance based upon lessons learned with Woodward's ARC Lite balance.  That balance was specifically designed so one could physically reorient the thruster without reorienting the power leads to it, so that if they were coupling, that coupling would not also flip--hence isolating the spurious from the actual thrust.  I can only presume Paul kept that protocol.  I haven't seen the detailed explanations of the Eagle balance that have been so public with Woodward's work, but Paul knows the value of that particular practice.

Thank you.

Concerning <<Paul helped design the Eagle balance based upon lessons learned with Woodward's ARC Lite balance>>

Question: Did Prof. Woodward's "ARC Lite balance" also use magnetic dampening ?
« Last Edit: 10/06/2014 04:45 PM by Rodal »

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #1612 on: 10/06/2014 04:53 PM »
Yes, but to a much lesser degree, and as I said, it is easy to isolate with a dummy load.  Woodward's thrusters form a perfect dummy load when the phase angle between the 1w and 2w portions of the signal are moved.  At 90* phase thrust is in one direction, and at 270* the other.  At 0* and 180* there is no thrust expected, so the thruster itself makes a perfect dummy load.

Woodward didn't have any coupling with the magnetic dampener.

Offline Rodal

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Re: EM Drive Developments
« Reply #1613 on: 10/06/2014 04:59 PM »
Yes, but to a much lesser degree, and as I said, it is easy to isolate with a dummy load.  Woodward's thrusters form a perfect dummy load when the phase angle between the 1w and 2w portions of the signal are moved.  At 90* phase thrust is in one direction, and at 270* the other.  At 0* and 180* there is no thrust expected, so the thruster itself makes a perfect dummy load.

Woodward didn't have any coupling with the magnetic dampener.
thanks.

And what specific kind of "Woodward's thruster" was tested by Woodward et.al. with that setup, the MLT or MET type of thruster?

Offline Mulletron

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Re: EM Drive Developments
« Reply #1614 on: 10/06/2014 05:09 PM »
Yes, but to a much lesser degree, and as I said, it is easy to isolate with a dummy load.  Woodward's thrusters form a perfect dummy load when the phase angle between the 1w and 2w portions of the signal are moved.  At 90* phase thrust is in one direction, and at 270* the other.  At 0* and 180* there is no thrust expected, so the thruster itself makes a perfect dummy load.

Woodward didn't have any coupling with the magnetic dampener.

Indeed on pages 10, 11, and 14. Dummy loads are mentioned. 10, 11 for Cannae. 14 for Emdrive. I gather that they used pretty darn good controls as experimentalist and this wasn't their first rodeo. They had lessons learned from previous campaigns. I do have issues with the seemingly small number of test campaigns, but I concede that it takes time to setup and run carefully. I have to bring up the fact that dummy loads by their very essence, convert rf to heat. How was the waste heat isolated? If, for instance, the waste heat of the dummy load were contributing to impulse EXACTLY the same as the test article, because the dominant effect was heat radiation, the dummy load null test would be invalid. So where was the dummy load? I can tell you from my own experience that dummy loads get very very hot.

Also, yes you are right, if the rf mode is setup where the standing wave is at minimum E, but max I at the boundary, it would be a dummy load and dump the rf as heat.

http://www.ece.rutgers.edu/~orfanidi/ewa/ch09.pdf

Here is a link with TMI on waveguide theory, and a Navy neets mod. See page 1-26 and on mostly. The whole thing will teach you so much.
« Last Edit: 10/06/2014 05:22 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Rodal

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Re: EM Drive Developments
« Reply #1615 on: 10/06/2014 05:21 PM »
Yes, but to a much lesser degree, and as I said, it is easy to isolate with a dummy load.  Woodward's thrusters form a perfect dummy load when the phase angle between the 1w and 2w portions of the signal are moved.  At 90* phase thrust is in one direction, and at 270* the other.  At 0* and 180* there is no thrust expected, so the thruster itself makes a perfect dummy load.

Woodward didn't have any coupling with the magnetic dampener.

Indeed on pages 10, 11, and 14. Dummy loads are mentioned. 10, 11 for Cannae. 14 for Emdrive. I gather that they used pretty darn good controls as experimentalist and this wasn't their first rodeo. They had lessons learned from previous campaigns. I do have issues with the seemingly small number of test campaigns, but I concede that it takes time to setup and run carefully. I have to bring up the fact that dummy loads by their very essence, convert rf to heat. How was the waste heat isolated? If, for instance, the waste heat of the dummy load were contributing to impulse EXACTLY the same as the test article, because the dominant effect was heat radiation, the dummy load null test would be invalid. So where was the dummy load? I can tell you from my own experience that dummy loads get very very hot.

Also, yes you are right, if the rf mode is setup where the standing wave is at minimum E, but max I at the boundary, it would be a dummy load and dump the rf as heat.
As way of background to @Mulletron's question, this is the excerpt from the report (p.14):

<<The net force is calculated by accounting for the null force present in the system. Null testing is performed by attaching the RF drive system to a 50 ohm load and running the system at full power. The null force testing indicated that there was an average null force of 9.6 micronewtons present in the as tested configuration. The presence of this null force was a result of the DC power current of 5.6 amps running in the power cable to the RF amplifier from the liquid metal contacts. This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system.>>

and Fig. 20 caption:

<<Figure 20. Null Test on Torsion Pendulum average null force is 9.6 micronewtons due to 5.6A DC current in power cable (routes power from liquid metal contacts to RF amplifier; interacts with magnetic damper system)>>

and see attached picture Fig. 13 RF Resistive Load mounted on torsion pendulum
« Last Edit: 10/06/2014 05:25 PM by Rodal »

Offline MikeMcCulloch

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Re: EM Drive Developments
« Reply #1616 on: 10/06/2014 05:27 PM »
Thank you for the warm welcome! Please note that I am at an early stage looking into the EmDrive. With some playful mathematics I found that MiHsC agrees with some EmDrive results, but the physics still needs more work, as I discuss here:
http://www.physicsfromtheedge.blogspot.co.uk/2014/10/mihsc-vs-emdrive-data-1.html
In the meantime I'd like to collect more data, so if anyone knows of any result not in the table on my blog please do let me know & I can collate it for all to see (I'll need the geometry of the cavity, power, Q, frequency and dielectic properties, all of which seem to be important, and of course the thrust observed).

Online aero

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Re: EM Drive Developments
« Reply #1617 on: 10/06/2014 05:28 PM »
I was looking for any evidence that dark matter interacts with RF waves. This leads to considering the red shift as perhaps due to dark matter interaction.

I found one guy who claims that dark matter does not exist, the missing mass is diatomic hydrogen. That was interesting so here is the link.

http://www.newtonphysics.on.ca/hydrogen/

I found another guy who claims that light interaction with dark matter does cause the red shift. That was more interesting because he gave some math. Under the constraints of his model, which seem valid for light in interstellar space, he gives the equation:

dp/dt = -H p as the change in momentum, p, of a photon, where H is the Hubble constant equals about 2.2 x 10^-18 per second.
Note that the value of H has been changing and being refined rapidly over the last few years. This value is from about 2013.

The reason this is interesting is because this change in momentum attributed to dark matter implies an equal and opposite change in momentum in the dark matter.

At this point I'm not going to derive the effect that this proposed coupling of RF wave photons and dark matter may have on the thruster cavity. It seems small though.

Here is the link:

http://arxiv.org/ftp/arxiv/papers/0704/0704.1044.pdf

Oh, this is a very popular thread, two posts during the time it took me to type mine. Gotta work on my typing speed.
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Offline Mulletron

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Re: EM Drive Developments
« Reply #1618 on: 10/06/2014 05:31 PM »
Yes, but to a much lesser degree, and as I said, it is easy to isolate with a dummy load.  Woodward's thrusters form a perfect dummy load when the phase angle between the 1w and 2w portions of the signal are moved.  At 90* phase thrust is in one direction, and at 270* the other.  At 0* and 180* there is no thrust expected, so the thruster itself makes a perfect dummy load.

Woodward didn't have any coupling with the magnetic dampener.

Indeed on pages 10, 11, and 14. Dummy loads are mentioned. 10, 11 for Cannae. 14 for Emdrive. I gather that they used pretty darn good controls as experimentalist and this wasn't their first rodeo. They had lessons learned from previous campaigns. I do have issues with the seemingly small number of test campaigns, but I concede that it takes time to setup and run carefully. I have to bring up the fact that dummy loads by their very essence, convert rf to heat. How was the waste heat isolated? If, for instance, the waste heat of the dummy load were contributing to impulse EXACTLY the same as the test article, because the dominant effect was heat radiation, the dummy load null test would be invalid. So where was the dummy load? I can tell you from my own experience that dummy loads get very very hot.

Also, yes you are right, if the rf mode is setup where the standing wave is at minimum E, but max I at the boundary, it would be a dummy load and dump the rf as heat.
As way of background to @Mulletron's question, this is the excerpt from the report (p.14):

<<The net force is calculated by accounting for the null force present in the system. Null testing is performed by attaching the RF drive system to a 50 ohm load and running the system at full power. The null force testing indicated that there was an average null force of 9.6 micronewtons present in the as tested configuration. The presence of this null force was a result of the DC power current of 5.6 amps running in the power cable to the RF amplifier from the liquid metal contacts. This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system.>>

and Fig. 20 caption:

<<Figure 20. Null Test on Torsion Pendulum average null force is 9.6 micronewtons due to 5.6A DC current in power cable (routes power from liquid metal contacts to RF amplifier; interacts with magnetic damper system)>>

and see attached picture Fig. 13 RF Resistive Load mounted on torsion pendulum

The dummy load was inside! Processing.......

Okay It wasn't elucidated that I can see, but in order to derive the  9.6 micronewton null force, you would have to take into account the thrust from the test article first, subtract the thrust (if any from the dummy load, which takes into account a lot of variables, including non linearaties of the heat produced by the dummy load itself coupled with the geometry of the test chamber. AND this is assuming the dummy load impulse effects were less than the test article, otherwise the dummy load's heat offload would dominate the impulse measured and it would appear thrust is happening, but they got the sign wrong...........(amiright?).You know what? This all sounds like BS because 1, we don't have enough info and 2 the effects are way small. I'm about to abandon this level of critical analysis of the paper because there are way too many assumptions based on too little info. The emdrive's supposed thrust is so close to the noise floor, that this way of analyzing it is not effective. We're gonna have to wait and see what other people do.
« Last Edit: 10/06/2014 05:45 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Rodal

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Re: EM Drive Developments
« Reply #1619 on: 10/06/2014 06:06 PM »
...

The dummy load was inside! Processing.......

Okay It wasn't elucidated that I can see, but in order to derive the  9.6 micronewton null force, you would have to take into account the thrust from the test article first, subtract the thrust (if any from the dummy load, which takes into account a lot of variables, including non linearaties of the heat produced by the dummy load itself coupled with the geometry of the test chamber. AND this is assuming the dummy load impulse effects were less than the test article, otherwise the dummy load's heat offload would dominate the impulse measured and it would appear thrust is happening, but they got the sign wrong...........(amiright?).You know what? This all sounds like BS because 1, we don't have enough info and 2 the effects are way small. I'm about to abandon this level of critical analysis of the paper because there are way too many assumptions based on too little info. The emdrive's supposed thrust is so close to the noise floor, that this way of analyzing it is not effective. We're gonna have to wait and see what other people do.
Well, these are some of the reasons why I have been bringing this up.  But there are more,  there are also magneto-thermo mechanical and dynamic aspects to this coupling as well.  That is why the classical set-up of Cavendish has been used to measure gravitational inverse-square law and the Casimir force in classical experiments and that's why Brito et al used a Cavendish type of setup with oil damping that falsified their inverted flexure beam experiments. 

I understand why Dr. White's team went this way: they wanted to have the setup to be small enough to fit inside their vacuum chamber.  This is the inverted pendulum they had. They did not have access to one as for example designed by Prof. Martinez-Sanchez at MIT to eliminate mode coupling between swinging and torsional modes.

Fine, we have to live with this: these are the experimental results we have and we need to take these issues into account in order to assess their validity.  So, we continue as we have been doing, we have made a lot of progress in analyzing this, and we should continue.

So, Ron's comments and answers concerning Mulletron's and my questions would still be appreciated, because the better we understand this coupling the better we can assess the significance of the results.

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