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#3580
by
Tellmeagain
on 06 Jul, 2016 16:50
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#3581
by
Rodal
on 06 Jul, 2016 16:56
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Probably Steve_D was referring to the reddit post, https://www.reddit.com/r/QThruster/comments/4riv6u/special_announcement_1701a_test_n10a73f/
So, it appears that
the data presented here for rfmwguy was due to thermal expansion of the power cable going to the magnetron ?The same problem that vitiated the data by Prof. Yang in China ?
That explains the thermal response: thermal exponential rise and thermal decaying exponential:
not due to thermal convection, but simply due to thermal expansion.
This would not happen if the tests would be powered by a self-contained battery...Prof. Yang's claims were nullified by running her tests powered with a self-contained battery
Shawyer has never reported a single test powered with a self-contained battery...
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#3582
by
tchernik
on 06 Jul, 2016 17:03
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I just want to commend Dave's honesty in this matter.
The sooner testers detect and remove these sources of errors, the better.
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#3583
by
Rodal
on 06 Jul, 2016 17:06
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
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#3584
by
tchernik
on 06 Jul, 2016 17:14
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
Yes, this seems to be the Achilles heel of this thruster idea (and several similar others). According to known physics, a self contained test device without external forces interacting with it shouldn't be able to move its center of gravity.
That means that if a battery powered tests with all external forces interacting with it removed doesn't show any displacement, then it is enough proof the Emdrive was mostly the result of thermal effects on the power cable.
The contrary would still allow some lingering doubts, but it would be a big boost to the credibility of the Emdrive.
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#3585
by
Tellmeagain
on 06 Jul, 2016 17:27
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
NASA EW's original test used liquid metal contacts, which was supposed to be immune from power line heat expansion problem.
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#3586
by
SteveD
on 06 Jul, 2016 17:29
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
Doc, one problem with the expanding wire hypothesis. 15mN is not a small amount of thrust when it comes to ion thrusters and the like. If an expanding lead could cause a 15mN anomaly then why isn't mention of it showing up in the Ion thruster literature. Additionally, I remember seeing some mention of NASA using an "integrated test article." The mini-EM Drive people believe that they have seen something with a fully integrated device (this may not be true).
Before you can say that this is clearly thermal expansion you have to do the work. To my mind that requires several steps:
1. Removing the can and testing for thrust with the leads simply going into a resistor.
2. An integrated test article with batteries testing both with and without HDPE insert.
Let me also point out that the magnetron or antenna assembly is something that is both inside and outside the can. Heating will cause a magnetized article to slowly demagnetize, losing energy and hence mass. Now 90% this really is thermal expansion of the wires, but if I had an unexplained thrust I might look at the thing that was both inside and outside of the closed system and was losing mass. Might want to do that resistor test first though.
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#3587
by
Rodal
on 06 Jul, 2016 17:34
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
NASA EW's original test used liquid metal contacts, which was supposed to be immune from power line heat expansion problem.
Didn't rfmwguy's original testing setup include Galinstan liquid contacts, and he eliminated them because of the obvious experimental artifacts they were producing in his initial tests ?
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#3588
by
TheTraveller
on 06 Jul, 2016 17:37
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Probably Steve_D was referring to the reddit post, https://www.reddit.com/r/QThruster/comments/4riv6u/special_announcement_1701a_test_n10a73f/
So, it appears that the data presented here for rfmwguy was due to thermal expansion of the power cable going to the magnetron ?
The same problem that vitiated the data by Prof. Yang in China ?
That explains the thermal response: thermal exponential rise and thermal decaying exponential: not due to thermal convection, but simply due to thermal expansion.
This would not happen if the tests would be powered by a self-contained battery...
Prof. Yang's claims were nullified by running her tests powered with a self-contained battery
Shawyer has never reported a single test powered with a self-contained battery...
That is not clear.
Dave's maggie has suffered a cracked magnet, so it needs to be replaced and further tests done to confirm the cable effect theory.
The observed power on thermal effects with the broken maggie versus working maggie power on are very, very much slower. The very slow rise time of the tests showing a thermal effect could not get close to the very rapid force rise time of the working maggie power on effects.
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#3589
by
Rodal
on 06 Jul, 2016 17:38
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
Doc, one problem with the expanding wire hypothesis. 15mN is not a small amount of thrust when it comes to ion thrusters and the like. If an expanding lead could cause a 15mN anomaly then why isn't mention of it showing up in the Ion thruster literature. Additionally, I remember seeing some mention of NASA using an "integrated test article." The mini-EM Drive people believe that they have seen something with a fully integrated device (this may not be true).
Before you can say that this is clearly thermal expansion you have to do the work. To my mind that requires several steps:
1. Removing the can and testing for thrust with the leads simply going into a resistor.
2. An integrated test article with batteries testing both with and without HDPE insert.
Let me also point out that the magnetron or antenna assembly is something that is both inside and outside the can. Heating will cause a magnetized article to slowly demagnetize, losing energy and hence mass. Now 90% this really is thermal expansion of the wires, but if I had an unexplained thrust I might look at the thing that was both inside and outside of the closed system and was losing mass. Might want to do that resistor test first though.
Also <<Before you can say that this is>> a force that can be used for space propulsion <<you have to do the work.>>:
1) I thought you stated that the magnetron was not firing.
...I'm afraid, since run 3 was a null, this chart shows that the vast majority of any reported effect must be thermal in nature. Since the magnetron did not fire during test 3, that means we are dealing with a cause other than heat from the magnetron. ...
If the magnetron was not firing, it clearly was not due to the EM Drive microwave producing a force that can be used for space propulsion
2) the decay of the force is way too slow to be electromagnetic in nature and it looks like a thermal exponential decay
3) the longer he heats the more displacement he gets?
Wasn't the EM Drive supposed to give a constant force for a constant power input?
Isn't his power input a constant during the test ? 900 watts?
---------
Bottom line: when you get experimental results that contradict your assumptions (constant force for constant power input, long exponential decay typical of thermal force) you should re-visit your assumption that this is a force that can be used for space propulsion
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#3590
by
FattyLumpkin
on 06 Jul, 2016 17:42
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To the best of my knowledge, Dave has every intention to test with the frustum in different positions on the pendulum and with the pendulum itself being located if various orientations: N, S, E... etc.
Additionally, following the testing "campaign" with the maggie he intends to move to a solid state signal generator/onboard power (as suggested by Dr. Rodal several times in previous NSF pages). As to the design of the pendulum or lack of a partial vacuum, indeed, state of the art facilities would be preferable, were one to possess the $$$$. I wonder what Cannae wants: $/hour for use of their setup?
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#3591
by
tchernik
on 06 Jul, 2016 17:46
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I want to remember the esteemed audience of this thread, that R. Shawyer showed a test device pushing itself in a rotary platform. Unless we say he was faking it, thermally expanding wires can only explain so much.
My take on Dave's findings is that he found a big artifact in his setup, and that he will avoid it in the future.
But I fully agree this emphasizes the need of a self contained battery-powered test.
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#3592
by
SteveD
on 06 Jul, 2016 17:47
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Actually, now that I stop to think about it the Traveller reported a "wow" signal after leaving his amplifier on all night feeding into the can while the rf source was turned off. He then pulsed a rf signal when he started his morning tests and his scale went over limited. After running all night, you'd think that the wires were as expanded as they were likely to get. Likewise Dave reported very little rf activity, but not no rf activity.
Like I said 90% it's just expanding wires but I'd still like to be sure that some form of unconventional effect related to heat (or the dissipation of heat) isn't involved.
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#3593
by
Tellmeagain
on 06 Jul, 2016 17:51
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
NASA EW's original test used liquid metal contacts, which was supposed to be immune from power line heat expansion problem.
Didn't rfmwguy's original testing setup include Galinstan liquid contacts, and he eliminated them because of the obvious experimental artifacts they were producing in his initial tests ?
They were constructed in different ways. It is hard to see whether the EW contacts suffer from the same artifacts.
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#3594
by
Rodal
on 06 Jul, 2016 18:07
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We hope that the next time we see a published report on the EM Drive by NASA Eagleworks, Shawyer, Tajmar, etc. they will run the test powered with a self-integrated battery !
Prof. Yang's results were nullified by running the test powered with a self-integrated battery
Brito, Marini and Galian nullified a type of MLT thruster by running the test powered with a self-integrated battery
NASA EW's original test used liquid metal contacts, which was supposed to be immune from power line heat expansion problem.
Didn't rfmwguy's original testing setup include Galinstan liquid contacts, and he eliminated them because of the obvious experimental artifacts they were producing in his initial tests ?
They were constructed in different ways. It is hard to see whether the EW contacts suffer from the same artifacts.
It depends on the boundary conditions and the movement. Galinstan expands with heat, its coefficient of thermal expansion is not zero.
The galinstan bath and the contacts may not be at uniform homogeneous temperature. Due to misalignment and movement the contacts may get too close to the walls, or worse, come in contact.
Furthermore Galinstan does not have zero viscosity. Furthermore its viscosity is a function of temperature and rate of change of fluid deformation.
If you would establish electrical contacts with a moving contact having friction, its effect (the frictional force) would be easier to understand, I suppose.
Extremely small forces are intended to be measured by experimentalists. The effects of different things that are usually ignored when measuring much larger forces , may suddenly raise their ugly head, no matter whether experimentalists wish that they would be negligible.
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#3595
by
TheTraveller
on 06 Jul, 2016 18:14
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Actually, now that I stop to think about it the Traveller reported a "wow" signal after leaving his amplifier on all night feeding into the can while the rf source was turned off. He then pulsed a rf signal when he started his morning tests and his scale went over limited. After running all night, you'd think that the wires were as expanded as they were likely to get. Likewise Dave reported very little rf activity, but not no rf activity.
Like I said 90% it's just expanding wires but I'd still like to be sure that some form of unconventional effect related to heat (or the dissipation of heat) isn't involved.
Actually everything was cold. Have a master AC off. What happened was I left the PowerAmp enable switched on and when I powered the whole system on, I got a thump and the battery powered scale went over limit, which I managed to repeat twice before my amp died from all the AC off and on cycles I did.
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#3596
by
SteveD
on 06 Jul, 2016 18:24
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1) I thought you stated that the magnetron was not firing.
You've read the same reddit post that I have. All that I can say is that Dave has indicated that the magnetron was not firing enough to substantiate the theory that 15mN of thrust was caused by resonant rf energy in the can.
If the magnetron was not firing, it clearly was not due to the EM Drive microwave producing a force that can be used for space propulsion.
2) the decay of the force is way too slow to be electromagnetic in nature and it looks like a thermal exponential decay
We have identified a source of experimental error and have developed a plan for dealing with it (place liquid metal connectors at the pivot) and/or we have observed that heat plays a role in some form of effect that does not conform of Shawyers' theories. Obviously, the thing to do is to implement the suggestion for mitigating the source of error, retest, then evaluate the results. Do you have a link to an English translation of Yangs latest paper?
3) the longer he heats the more displacement he gets?
Since this was a horizontal test, shouldn't we expect the beam to continue to move horizontally though at a slower rate as the twisting of the various wires impose resistance (at least until some critical point)? The longer the test lasts, the more the beam moves. Objects in motion do have a tendency to remain in motion.
Wasn't the EM Drive supposed to give a constant force for a constant power input?
Isn't his power input a constant during the test ? 900 watts?
No, simply that it appears to give constant force for constant power at the velocities within the limits of the measuring apparatus.
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#3597
by
FattyLumpkin
on 06 Jul, 2016 18:50
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RE Yang's most recent publication: I don't recall what the final NSF consensus was re the "results", however, having studied what is available in English, indeed, Yang does nullify the "significant" thrust measurements/results form her previous study. However, in her latest study the test equipment she used was only sensitive to forces = or >300 micro Newtons. This being the case forces of < 300 micro Newtons +/- 14% cannot be R/O.
"The results show that three-wire torsion pendulum thrust measurement system can measure thrust not less than 3 mN under the existing experimental conditions with the relative uncertainty of 14%"
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#3598
by
Tellmeagain
on 06 Jul, 2016 18:56
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It depends on the boundary conditions and the movement. Galinstan expands with heat, its coefficient of thermal expansion is not zero.
The galinstan bath and the contacts may not be at uniform homogeneous temperature. Due to misalignment and movement the contacts may get too close to the walls, or worse, come in contact.
Furthermore Galinstan does not have zero viscosity. Furthermore its viscosity is a function of temperature and rate of change of fluid deformation.
If you would establish electrical contacts with a moving contact having friction, its effect (the frictional force) would be easier to understand, I suppose.
Extremely small forces are intended to be measured by experimentalists. The effects of different things that are usually ignored when measuring much larger forces , may suddenly raise their ugly head, no matter whether experimentalists wish that they would be negligible.
Also the surface tension. I agree with you on better using integrated batteries.
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#3599
by
TheTraveller
on 06 Jul, 2016 18:57
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1) I thought you stated that the magnetron was not firing.
You've read the same reddit post that I have. All that I can say is that Dave has indicated that the magnetron was not firing enough to substantiate the theory that 15mN of thrust was caused by resonant rf energy in the can.
Steve,
I'm in the very private email discussion group that is working with Dave. He doesn't know when the top ring magnet cracked other that it was not working when he did his last test run. The bad maggie is being replaced and a few other suggested tidy ups implemented before restarting the test series.
New items will be using a phase change substance to limit the maggie temp increase as Dave has lost 2 maggies to overheat plus better monitoring of the maggie anode voltage to see if it is possible, as I believe it is, to detect when maggie to frustum lock occurs and a better feed of the high current to the maggie that should not cause any issues with the filament current.
There is a lot of work yet to be done.
But I say again, none of the measured thermal effects with the frustum small end pointing UP has shown anything like the very rapid initial force generation when the maggie locks to the frustum.
I should add, the observed delay time with just a side flick of a pen on the side of the beam and the active power off decay time are around the same value of 5 minutes, 20 seconds, which suggests there is not much thermal in the power off decay.