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#720 by SeeShells on 30 Mar, 2016 21:50
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My experience at MIT is that MIT students build their own instruments, many times with very low budgets.
For example, personally, from the time that I was a freshman, I was machining (under UROP: Undergraduate Research Opportunity Program at MIT) the nozzles for a research project with a hybrid rocket engine (nozzles made machined from solid graphite, hybrid rocket solid was simply a "Lexan" polycarbonate thick cylinder. MIT had a huge number of lathes and other equipment to fabricate instruments and experiments.
Concerning a budget, a torsional pendulum (a Cavendish pendulum) is not more expensive than any of the Teeter-Totter instruments featured in these threads by DIY.
For the reasons discussed here: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509734#msg1509734 such a torsional pendulum is a better instrument to measure micro-thrust of an electromagnetic thruster.
Actually the Cavendish pendulum fabricated by Brito, Marini and Galian in remote Argentina is cheaper, and requires an even lower budget. See how simple and low budget it is to make such a torsional pendulum:
This shows that it is incorrect to say that a Teeter-Totter is more inexpensive than a Cavendish torsional pendulum.
Such an experimental method was used by Brito, Marini and Galian to nullify a battery-powered "Mach Lorentz" electromagnetic propellant-less thruster:
Null Findings on Electromagnetic Inertia Thruster Experiments using a Torsion Pendulum
45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2 - 5 August 2009, Denver, Colorado
and by Marini and Galian in their peer-reviewed article in the AIAA Journal of Propulsion and Power:
Ricardo L. Marini and Eugenio S. Galian. "Torsion Pendulum Investigation of Electromagnetic Inertia Manipulation Thrusting", Journal of Propulsion and Power, Vol. 26, No. 6 (2010), pp. 1283-1290.
Dr. Rodal, you're quite right it isn't that costly to build. The goal in my teeter todder stand it to address two questions pressure and acceleration and the beam can accomadate both on the same stand.
Considering that both data sets can be cross checked against each other using the same test stand and same drive it seemed a reasonable compromise in the build.
I may build a Cavendish torsional pendulum at a later date.
Shell -
#721 by Rodal on 30 Mar, 2016 21:53
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...
Dr. Rodal, you're quite right it isn't that costly to build. The goal in my teeter todder stand it to address two questions pressure and acceleration and the beam can accomadate both on the same stand.
Considering that both data sets can be cross checked against each other using the same test stand and same drive it seemed a reasonable compromise in the build.
I may build a Cavendish torsional pendulum at a later date.
Shell
Excellent
When comparing experimental results we should always strive to consider what testing device was used (I made that point previously when people were comparing unreported results with asymmetrically placed dielectrics from a Teeter-Totter with the results obtained from a torsional pendulum).
Ideally, the equation of motion for the testing device should be analyzed to assess the significance of the measurement. -
#722 by tchernik on 30 Mar, 2016 22:07
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* The lowest measured anomalous force were obtained by:
a) NASA Eagleworks using a torsional pendulum
b) Tajmar using a torsional pendulum
The fact those measurements are small, yet still there while using the right instruments is what I find the most intriguing about this all affair.
Anything better than a photon rocket is a revolution, even if it doesn't give us flying cars or manned trips to Mars (in the short term). -
#723 by Rodal on 30 Mar, 2016 22:11
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* The lowest measured anomalous force were obtained by:
a) NASA Eagleworks using a torsional pendulum
b) Tajmar using a torsional pendulum
The fact those measurements are small, yet still there while using the right instruments is what I find the most intriguing about this all affair.
Anything better than a photon rocket is a revolution, even if it doesn't give us flying cars or manned trips to Mars (in the short term).
Beautifully stated: <<Anything better than a photon rocket is a revolution>> for a photonic drive (*)
I agree with you, that's why I'm still here 
_____
(*) the photonic laser thruster doesn't count because it is comprised of two spaceships: the center of mass-energy of the two spaceships does not accelerate, ever. The resource ship has to move in the opposite direction as the spaceship. A large infrastructure of resource ships is needed for long trips. -
#724 by rq3 on 30 Mar, 2016 22:30
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Some of the best thrust stands for microthrusters are tortion bars used with interferometers. This is similar to what I am going for. http://photonicassociates.com/ISBEP4-2.pdf
Tomorrow I get the aluminum support piece that runs along the top of the stand that the emdrive will hang from.
If that corner cube is supposed to do what I think you intend, it won't. -
#725 by FattyLumpkin on 30 Mar, 2016 23:49
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Is it completely unrealistic to suggest that EWL might be open to testing a DIYer's build if a significant thrust were indicated even by a DIYer's not so perfect equipment?
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#726 by Rodal on 31 Mar, 2016 00:05
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Is it completely unrealistic to suggest that EWL might be open to testing a DIYer's build if a significant thrust were indicated even by a DIYer's not so perfect equipment?
Don't know whether Eagleworks may be willing and able to test or not. (In 2014 they tested the Fetta "Cannae" device for example. In 2013, the Eagleworks team tested a device called the Serrano Field Effect Thruster, built by Gravitec Inc. at the request of Boeing and DARPA. Previously they also tested several other devices including a Mach Lorentz thruster, based on the Woodward effect). But I want to remark that:
1) A Cavendish pendulum is quite an inexpensive instrument that any DIY should be able to build (please refer to the previously posted picture of the pendulum used by Brito, Marini and Galian in Argentina), even cheaper than certain kinds of Teeter-Totter devices: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509771#msg1509771
2) What may be measured in a Teeter-totter may not be any thrust at all: for example one may be measuring just thermal expansion. Thermal expansion is not thrust: a spaceship's drive suffering thermal expansion will just get bigger, but it will not be self-accelerated by that expansion. Any resonant EM Drive experiences induction heating. Induction heating occurs at the speed of light. Thermal expansion of the copper in the EM Drive occurs at the speed of sound in the copper (which is 5 kilometers per second: it is much higher than the speed of sound in air).
One should analyze the equations of motion of a Teeter-totter to analyze the significance of the measurement.
At the very least, anyone using a Teeter-Totter should reverse the orientation of the EM Drive and measure the force with the EM Drive oriented in the reversed orientation. -
#727 by rfmwguy on 31 Mar, 2016 00:18
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If we talk torsion testing, let's get an expert like mr. Li (tellmeagain) involved here to advise builders about false readings as discussed in his paper. I trust his hands on experience.
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#728 by Rodal on 31 Mar, 2016 00:25
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If we talk torsion testing, let's get an expert like mr. Li (tellmeagain) involved here to advise builders about false readings as discussed in his paper. I trust his hands on experience.
I don't recall the contents of that paper. Does Mr. Li favor the Teeter-Totter measurement device over the Cavendish pendulum in the paper?
Is there an analysis with examples Li cites with torsional testing applications to rocket electromagnetic thrusters or gravitational measurements in the paper? Is there a link to the paper or a citation to find and read the paper ?
Do get him....(and the paper link or citation please) -
#729 by meberbs on 31 Mar, 2016 00:41
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The advise is based on experimental data. Ignore it at your peril.
As for space, there will need to be some level of background vibration to trigger what Roger calls Motor mode. This has been discussed many times before.
Doesn't matter if you believe Roger's explination of why this is necessary or not. That this occurs is an experimental fact & ignoring it could result in no force generation.
What exactly is required to make it work? You say vibration, but that isn't very specific, all of the atoms in the walls of the drive are vibrating with thermal energy.
You call this "experimental fact" but the description so far sounds to me like an experimental setup that has static friction greater than the generated thrust. Even an air track has some (very small) static friction based on some of the recent discussion. Keep in mind that the emDrive having any effect at all isn't an experimental fact yet, since there is no conclusive data available.
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#730 by Tellmeagain on 31 Mar, 2016 01:01
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Some of the best thrust stands for microthrusters are tortion bars used with interferometers. This is similar to what I am going for. http://photonicassociates.com/ISBEP4-2.pdf
Tomorrow I get the aluminum support piece that runs along the top of the stand that the emdrive will hang from.
Each side should have an oil damper. Other wise the movement will not be smooth. An decaying oscillation will be added to the otherwise smooth movement. This is from my own experience with the paper submitted to The Physics Teacher. -
#731 by mwvp on 31 Mar, 2016 01:01
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Please note the following:
http://www.emdrive.com/EmDriveForceMeasurement.pdfQuoteA number of methods have been used in the UK, the US and China
to measure the forces produced by an EmDrive thruster.
In each successful case, the EmDrive force data has been superimposed
on an increasing or decreasing background force, generated by the test
equipment itself.
Indeed, in the UK when the background force changes were eliminated,
in an effort to improve force measurement resolution, no EmDrive force
was measured.
For an EM Drive in outer space there is no such thing as a "background force". Taking the following quotation literally:QuoteIndeed, in the UK when the background force changes were eliminated,
in an effort to improve force measurement resolution, no EmDrive force
was measured.
one would surmise that there is no "Shawyer EM Drive" force to be measured for a Shawyer EM Drive device in outer space, according to that quotation. Hence no outer space propulsion ?
There are no reported "UK measurements" of the EM Drive "force" in vacuum. Were measurements in vacuum ever attempted by SPR Ltd.? Or were they attempted and no force was measured by SPR Ltd. in vacuum?
The advise is based on experimental data. Ignore it at your peril.
As for space, there will need to be some level of background vibration to trigger what Roger calls Motor mode. This has been discussed many times before.
Doesn't matter if you believe Roger's explination of why this is necessary or not. That this occurs is an experimental fact & ignoring it could result in no force generation.
"Trigger" the "Motor mode"?
Trigger and mode imply some kind of composite mechanism, like a firearm or mouse-trap. May I elaborate? I'm reluctant, as I doubt it will or perhaps can be appreciated, having tried before, and suspecting the cherished hopes of new-physics and elaborate theories being dashed is unbearable to some. Nevertheless...
Once upon a time I blurted out: http://forum.nasaspaceflight.com/index.php?topic=39004.msg1484276#msg1484276which featured this illustration:
and the document http://arxiv.org/abs/1303.0733 from whence it came.
If a piston separates high pressure from low pressure gas in a cylinder, or a rocket nozzle, force and acceleration may result.
In photonic damping (cooling) and amplification, there is the "density of states" (tuning) and damping/loss in the optical cavity (see below)
If there is no acceleration/vibration induced doppler shift, there will be no imbalance of radiation pressure. In space or free-fall, there will be no external damping to stop it BUT if the frustrum is flimsy, I suspect some acoustic mode may start vibrating the frustrum and dissipate energy from the desired acceleration.
The frustrum is both a photonic/microwave cavity filled with radiation pressure, and a mechanical "resonator" of sorts, in its inertial frame. Ideally it would continuously accelerate, but in practice it will be electrically pulsed and mechanically vibrated against a ballast for a couple reasons. Similar to what Woodward intends.
Oh I forgot to add, Peltier coolers, which have electron-dispersive junctions similar to the microwave dispersive frustrum, and pump heat like the photonic cooler, have been reported to produce exhaust-less thrust (heat notwithstanding), similar to the EM drive.
FWIW, YMMV.
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#732 by TheTraveller on 31 Mar, 2016 01:07
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Keep in mind that the emDrive having any effect at all isn't an experimental fact yet, since there is no conclusive data available.
Keep in mind that is your opinion. To others there are conclusive data available.
If you read Roger's papers, he makes it very clear a stationary EmDrive needs to experience some slight acceleration, big end to small end, to tigger Motor mode & further self acceleration. -
#733 by rfmwguy on 31 Mar, 2016 01:13
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Here is the paper link from T5:If we talk torsion testing, let's get an expert like mr. Li (tellmeagain) involved here to advise builders about false readings as discussed in his paper. I trust his hands on experience.
I don't recall the contents of that paper. Does Mr. Li favor the Teeter-Totter measurement device over the Cavendish pendulum in the paper?
Is there an analysis with examples Li cites with torsional testing applications to rocket electromagnetic thrusters or gravitational measurements in the paper? Is there a link to the paper or a citation to find and read the paper ?
Do get him....(and the paper link or citation please)
https://forum.nasaspaceflight.com/index.php?topic=38577.msg1443188#msg1443188 -
#734 by TheTraveller on 31 Mar, 2016 01:13
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....
To understand the EmDrive's Idle, Motor & Generator mode please read Roger's various papers at www.emdrive.com
Has been discussed here several times & in some detail. -
#735 by Tellmeagain on 31 Mar, 2016 01:16
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If we talk torsion testing, let's get an expert like mr. Li (tellmeagain) involved here to advise builders about false readings as discussed in his paper. I trust his hands on experience.
I don't recall the contents of that paper. Does Mr. Li favor the Teeter-Totter measurement device over the Cavendish pendulum in the paper?
Is there an analysis with examples Li cites with torsional testing applications to rocket electromagnetic thrusters or gravitational measurements in the paper? Is there a link to the paper or a citation to find and read the paper ?
Do get him....(and the paper link or citation please)
Dr. Rodal,
Spanish reporter JAVIER YANES mentioned our (father and daughter) paper on his report of EmDrive,
https://translate.google.com/translate?hl=en&sl=es&u=http://www.elespanol.com/ciencia/20151120/80741967_0.html&prev=search
He linked to the paper which is at, http://arxiv.org/abs/1510.07752 . The paper was submitted to The Physics Teacher and after 180 days it is still under review.
Also rfmwguy (Thank you!) had just posted the link.
Best,
Tellmeagain
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#736 by Rodal on 31 Mar, 2016 01:19
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If we talk torsion testing, let's get an expert like mr. Li (tellmeagain) involved here to advise builders about false readings as discussed in his paper. I trust his hands on experience.
I don't recall the contents of that paper. Does Mr. Li favor the Teeter-Totter measurement device over the Cavendish pendulum in the paper?
Is there an analysis with examples Li cites with torsional testing applications to rocket electromagnetic thrusters or gravitational measurements in the paper? Is there a link to the paper or a citation to find and read the paper ?
Do get him....(and the paper link or citation please)
Dr. Rodal,
Spanish reporter JAVIER YANES mentioned our (father and daughter) paper on his report of EmDrive,
https://translate.google.com/translate?hl=en&sl=es&u=http://www.elespanol.com/ciencia/20151120/80741967_0.html&prev=search
He linked to the paper which is at, http://arxiv.org/abs/1510.07752 . The paper was submitted to The Physics Teacher and after 180 days it is still under review.
Also rfmwguy (Thank you!) had just posted the link.
Best,
Tellmeagain
Thank you !
I just speed-read your paper (from the link provided by rfmwguy), and it looks (please correct me if I'm wrong) that you actually used a TORSIONAL PENDULUM.
Which is what I wrote is favored (by the academic and institutional R&D community) over the Teeter-Totter used by rfmwguy. Please see, for example: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509734#msg1509734
So I don't understand rfmwguy's post. Have you changed your mind and you now favor the Teeter-Totter over the torsional pendulum ? If so, why?
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#737 by Tellmeagain on 31 Mar, 2016 01:22
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Thank you !
I just speed-read your paper (from the link provided by rfmwguy), and it looks (please correct me if I'm wrong) that you actually used a TORSIONAL PENDULUM.
Which is what I wrote is favored over the Teeter-Totter used by rfmwguy. Please see, for example: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509734#msg1509734
So I don't understand rfmwguy's post. Have you changed your mind and you now favor the Teeter-Totter over the torsional pendulum ? If so, why?
I think you misunderstood him. I don't see from his post that he implied me favor Teeter-Totter over the torsional pendulum. And I don't. -
#738 by mwvp on 31 Mar, 2016 01:35
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....
To understand the EmDrive's Idle, Motor & Generator mode please read Roger's various papers at www.emdrive.com
Has been discussed here several times & in some detail.
Yea, OK. I intend to review it again, for the third or fourth time since its been a few months. Hopefully, very soon, I shall demonstrate graphically with simulations that in a perfect cavity the upper and lower sidebands result in a counter-propagating group velocity waveform, but when inductive, skin-effect, but moreover, frequency-discriminating losses are considered in the dispersive frustrum, it will be proven that the net group velocity is towards the tail, causing the radiation pressure imbalance and thrust.
What I am describing is theoretically and experimentally testable. We shall see.
For instance, the illustration suggests the energy should be close but just above cavity resonance:
Shawyer has, IMHO, not been entirely forthcoming. Understandably, for me anyways. -
#739 by Rodal on 31 Mar, 2016 01:50
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Thank you !
I just speed-read your paper (from the link provided by rfmwguy), and it looks (please correct me if I'm wrong) that you actually used a TORSIONAL PENDULUM.
Which is what I wrote is favored over the Teeter-Totter used by rfmwguy. Please see, for example: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509734#msg1509734
So I don't understand rfmwguy's post. Have you changed your mind and you now favor the Teeter-Totter over the torsional pendulum ? If so, why?
I think you misunderstood him. I don't see from his post that he implied me favor Teeter-Totter over the torsional pendulum. And I don't.
I read this post as saying that the Teeter-Totter may be preferred by DIY because of a lower budget and locale:I admire the ideal test stand advice and concede that ... teeter totters are less than ideal, but we might be getting ahead of ourselves. DIY test stands are certainly budget constrained, but believe what most DIY experimenters are striving for are personal Observational Results as opposed to a high-level institutional replication. In many cases, DIYers neither have the locale, equipment nor the budget; so my point is that any test stand that provides so my point is that any test stand that provides Observed results is useful.
...
but that doesn't necessarily follow either (see the picture of Brito, Marini and Galian's inexpensive torsional pendulum built in Argentina: https://forum.nasaspaceflight.com/index.php?topic=39772.msg1509771#msg1509771 ). A torsional pendulum is not more expensive than a Teeter-Totter. Concerning "the locale", it is actually the Teeter-Totter that may take more room (if a long Teeter-Totter beam is used as by the above DIY example).
Did your torsional pendulum require a much larger budget, not affordable by a DIY than the DIY Teeter-Totter ? Or did your torsional pendulum require a special locale not available to a DIY ?
