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#1640 by Monomorphic on 26 Apr, 2016 13:59
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Please tell us what you see...Torsion pendulum
http://cannae.com/cannaes-new-torsion-pendulum/
Lots to see here...
I'm not sure if it is intentional to use the high resolution images on the website, but these have not been downsized for web. It's hard to know where to start.
Their summary is pretty good"We have some unique features built into our equipment including liquid metal contacts which can be disengaged during test runs, laser micrometer and irradiance meter displacement sensors, Li-ion vacuum battery power sources, and high voltage operational capability. The whole test apparatus is located in a 36 inch diameter vacuum chamber base (visible in the picture). "
I was able to see a little more clearly what is on the screen.
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#1641 by Rodal on 26 Apr, 2016 14:05
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Please tell us what you see...Torsion pendulum
http://cannae.com/cannaes-new-torsion-pendulum/
Lots to see here...
I'm not sure if it is intentional to use the high resolution images on the website, but these have not been downsized for web. It's hard to know where to start.
Their summary is pretty good"We have some unique features built into our equipment including liquid metal contacts which can be disengaged during test runs, laser micrometer and irradiance meter displacement sensors, Li-ion vacuum battery power sources, and high voltage operational capability. The whole test apparatus is located in a 36 inch diameter vacuum chamber base (visible in the picture). "
I was able to see a little more clearly what is on the screen.
"battery power sources,"
does this mean that his test is battery powered and the batteries are self-contained in the torsional pendulum?
If so, this would be a marvelous test:
1) Torsional pendulum much superior to teeter-totter, as shown in experiments in Aerospace Industry and universities since the 1950's with electromagnetic micro-thrusters. The teeter-totter being a notorious unconvincing and bad test because of its lack of stiffness, hence the steady-state force being governed by whatever damping device is used to dampen its motion. As compared to the torsional pendulum, where the steady-state force is governed by the well specified torsional stiffness of the torsional pendulum.
2) battery-powered self-integrated means that the center of mass-energy is in the testing rig, which is much more convincing than most experiments (DIY, Shawyer, Tajmar, Shieh, etc.) that have the center of energy outside the testing rig.
It looks like Guido Fetta has been following good scientific advice, which is very encouraging !!! -
#1642 by Vesc on 26 Apr, 2016 14:07
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Please tell us what you see...Torsion pendulum
http://cannae.com/cannaes-new-torsion-pendulum/
Lots to see here...
Looks like they are also set up to test with the unslotted device, which was originally supposed to be the non-thrusting control device, but when EW tested it, saw thrust as well. I can't tell for sure (from the picture) if they are using a dielectric insert.
Also there's a spectrum analyzer running in the background, plotting a bell shape. But I can't make out the center freq. Resolution is not good enough... -
#1643 by Vesc on 26 Apr, 2016 14:18
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If so, this would be a marvelous test:
1) Torsional pendulum much superior to teeter-totter, as shown in experiments in Aerospace Industry and universities since the 1950's. The teeter-totter being a notorious unconvincing and bad test because of its lack of stiffness, hence the steady-state force being governed by whatever damping device is used to dampen its motion. As compared to the torsional pendulum, where the steady-state force is governed by the well specified torsional stiffness of the torsional pendulum.
2) battery-powered self-integrated means that the center of mass-energy is in the testing rig, which is much more convincing than most experiments (DIY, Shawyer, Tajmar, Shieh, etc.) that have the center of energy outside the testing rig.
IIRC, EW used a torsional pendulum and was able to calibrate it for deflection forces using electromagnets as controls. -
#1644 by Rodal on 26 Apr, 2016 14:29
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Emidio Laureti has been patiently posting in the "other" forum, his experimental results and explanations for his PNN Q-Thruster. Unfortunately his discussions are met by name-calling and vituperations, without calculations, without using mathematical analysis (which are the hallmark of Physicists and Engineers, instead of using words and "laws").
I wonder whether Emidio Laureti could post here instead, where he may be met with strong objective criticism, but it would be moderated so that the criticism is scientific, focusing on experiments and calculations, instead of vituperations and name calling. It is encouraging that Emidio's reaction to vituperation has been to use a gentle sense of humor and he has not been defensive at all, so it may be worthwhile to have a discussion with him that is free of invectives, and concentrates instead on his PNN experiments from a scientific viewpoint instead.
These are the 2015 claims for the PNN F242 performance:
• Force: 600uN (with a tolerance of +- 100uN)
• Input power 150W
• Force/InputPower = 4 mN/kW (comparable to NASA TM212 2014 report, and to Iulian Berca's results)
Still, much lower than Cannae Superconducting, and Yang's non-superconducting EM Drive claimed 1,000 mN/kW
Here: https://neolegesmotus.wordpress.com/2016/04/24/f242-is-now-at-2-56-grams-of-thrust/
2.56 grams of thrust (25 milliiNewtons) are claimed at 180 W, in 2016, which gives:
• Force/InputPower = 139 mN/kW
which is comparable to Shawyer's Demonstrator and Flight Thruster, but still below Yang's claims.
Also, he claims that PNN F242 is 10 times lighter than the EmDrive. Not clear what are his assumptions in this regard.
Don't know why the contraption features a red cross pattée. The form appears very early in medieval art, for example in a metalwork treasure binding given to Monza Cathedral by Queen Theodelinda (d. 628), queen of the Lombards in Italy, and is often associated with the Crusades, sometimes used by the Teutonic Knights, and the Knigths Templar.
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#1645 by OttO on 26 Apr, 2016 14:47
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Below is the link for an old article:
http://arxiv.org/abs/0707.1216
Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk
So my question is this: With Cu ions and polymer can we manage to make something acting like a ferrit.
If so perhaps the stuff will act like a kind of gyroscope.
The effect if big enough will be strange: motor mode and resisting mode... due to precession for example -
#1646 by Rodal on 26 Apr, 2016 14:50
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Below is the link for an old article:
http://arxiv.org/abs/0707.1216
Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk
So my question is this: With Cu ions and polymer can we manage to make something acting like a ferrit.
If so perhaps the stuff will act like a kind of gyroscope.
The effect if big enough will be strange: motor mode and resisting mode... due to precession for example
To fix concepts, what in the EM Drive would be the rotor and what would be the stator of such a motor ?
What stationary medium would the EM Drive "screw" itself into?
Does this imply a notion of the Quantum Vacuum as a medium with respect to which the EM Drive can accelerate?
We are back to Frobnicat's "road" issues: what is the "road" and the issues of frame-indifference. -
#1647 by OttO on 26 Apr, 2016 15:15
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Below is the link for an old article:
http://arxiv.org/abs/0707.1216
Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk
So my question is this: With Cu ions and polymer can we manage to make something acting like a ferrit.
If so perhaps the stuff will act like a kind of gyroscope.
The effect if big enough will be strange: motor mode and resisting mode... due to precession for example
To fix concepts, what in the EM Drive would be the rotor and what would be the stator of such a motor ?
What stationary medium would the EM Drive "screw" itself into?
Does this imply a notion of the Quantum Vacuum as a medium with respect to which the EM Drive can accelerate?
We are back to Frobnicat's "road" issues: what is the "road" and the issues of frame-indifference.
Well if we have a gyroscopic effect then the detected force would be a kind of artefact and no star drive
And to test it on a rotating apparatus would be the worst to do it would be like putting a powerball on the thing.
http://www.powerballs.com/how-it-works/
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#1648 by Rodal on 26 Apr, 2016 16:05
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Below is the link for an old article:
http://arxiv.org/abs/0707.1216
Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk
So my question is this: With Cu ions and polymer can we manage to make something acting like a ferrit.
If so perhaps the stuff will act like a kind of gyroscope.
The effect if big enough will be strange: motor mode and resisting mode... due to precession for example
To fix concepts, what in the EM Drive would be the rotor and what would be the stator of such a motor ?
What stationary medium would the EM Drive "screw" itself into?
Does this imply a notion of the Quantum Vacuum as a medium with respect to which the EM Drive can accelerate?
We are back to Frobnicat's "road" issues: what is the "road" and the issues of frame-indifference.
Well if we have a gyroscopic effect then the detected force would be a kind of artefact and no star drive
And to test it on a rotating apparatus would be the worst to do it would be like putting a powerball on the thing.
http://www.powerballs.com/how-it-works/
Excellent, insightful points
That's why I do like the fact that Monomorphic is going to be testing in a linear bearing.
On the other hand the linear bearing (of course it has drawbacks, no measurement apparatus is perfect) brings the fact that it is not a rotational test, unlike the torsional pendulum and unlike the teeter totter. -
#1649 by zellerium on 26 Apr, 2016 17:20
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I'll start work on cutting the pieces for the wedge today. I'm hoping to incorporate a waveguide this time, instead of direct insertion of the magnetron.
Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting -
#1650 by Rodal on 26 Apr, 2016 17:34
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I'll start work on cutting the pieces for the wedge today. I'm hoping to incorporate a waveguide this time, instead of direct insertion of the magnetron.
Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting
Welcome back Zellerium. Thank you for updating your experimental data in the wiki EMDrive tabulation.
Do you have any comments on the following ?
http://arxiv.org/abs/1506.04248QuoteHere we report the direct observation of an extraordinary optical momentum and force directed perpendicular to the wavevector, and proportional to the optical spin (i.e., degree of circular polarization). This transverse spin-dependent optical force, a few orders of magnitude weaker than the usual radiation pressure, was recently predicted for evanescent waves [10] and other structured fields
A force, perpendicular to the longitudinal axis, has been measured and reported by several EM Drive experimenters, including at these Universities in Germany and in the USA:
* Prof. Tajmar et.al at TU Dresden
* Zeller, Kraft, Echols at California Polytechnic State Univ., San Luis Obispo, USA
I do notice that the force is a few orders of magnitude weaker than the usual radiation pressure, but it is in the perpendicular direction, and who knows whether it may be subject to magnification (as remarked by Rotosequence)
Are you absolutely positive that the perpendicular force you measured was due to Lorentz forces due to the cables? Was it reduced by moving the cables? -
#1651 by Monomorphic on 26 Apr, 2016 17:46
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Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting
Thank you for the kind words!
I've been running sims on the waveguide today and noticed the TM mode excitation. Have already changed the orientation back to TE.
Didn't X_Ray also talk about a narrow band accepting aperture recently? He called it a periodic bandpassfilter.
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#1652 by zellerium on 26 Apr, 2016 17:54
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I'll start work on cutting the pieces for the wedge today. I'm hoping to incorporate a waveguide this time, instead of direct insertion of the magnetron.
Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting
Welcome back Zellerium. Thank you for updating your experimental data in the wiki EMDrive tabulation.
Do you have any comments on the following ?
http://arxiv.org/abs/1506.04248QuoteHere we report the direct observation of an extraordinary optical momentum and force directed perpendicular to the wavevector, and proportional to the optical spin (i.e., degree of circular polarization). This transverse spin-dependent optical force, a few orders of magnitude weaker than the usual radiation pressure, was recently predicted for evanescent waves [10] and other structured fields
A force, perpendicular to the longitudinal axis, has been measured and reported by several EM Drive experimenters, including at these Universities in Germany and in the USA:
* Prof. Tajmar et.al at TU Dresden
* Zeller, Kraft, Echols at California Polytechnic State Univ., San Luis Obispo, USA
I do notice that the force is a few orders of magnitude weaker than the usual radiation pressure, but it is in the perpendicular direction, and who knows whether it may be subject to magnification (as remarked by Rotosequence)
Are you absolutely positive that the perpendicular force you measured was due to Lorentz forces due to the cables? Was it reduced by moving the cables?
I believe the perpendicular force we observed was due to a lorentz force caused by the grounding wire which had not been intertwined with the postive and negative wires. I'm not sure of the connection to the paper you linked but unfortunately I don't have time to dive into it today.
I have successfully eliminated the horizontal deflection and have been observing slight vertical deflection (ie axial force) but only on certain occasions.
The sensitivity of our resonance is probably responsible for the inconsistent results: Our VNA is located in another building and we have been attempting to 'lock' the resonance and carry the cylinder over to the testing setup. When it is attached to the VNA it usually only takes a light tap to cause the resonance to shift or disappear completely.
Luckily a professor has purchased a portable VNA that I'll be using soon (this weekend perhaps) and I'll be able to lock a resonant position without moving the cavity and hopefully get some repeatable axial forces.
The deflections I have seen have been between 1~5 mN, just barely above the noise of our pendulum.
I also want to borrow a thermal camera to get a better idea of the heat distribution and the possible force caused by it.
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#1653 by zellerium on 26 Apr, 2016 18:03
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Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting
Thank you for the kind words!
I've been running sims on the waveguide today and noticed the TM mode excitation. Have already changed the orientation back to TE.
Didn't X_Ray also talk about a narrow band accepting aperture recently? He called it a periodic bandpassfilter.
Ah yes, that definitely looks like an elegant solution. I guess the trick would be sizing everything so that the intermediate cavities can dissipate enough heat to withstand deformation to maintain their resonant properties. I'd be afraid of the first cavity rejecting too much back to the magnetron. Maybe some absorbtive load inside could mitigate that effect?
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#1654 by Monomorphic on 26 Apr, 2016 18:21
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In lieu of a custom waveguide, I am considering using the waveguide that was mounted in the microwave. I think I can mount this fairly easily to the wedge geometry since it has flat side-walls. That little bump out will be inside the cavity, but I don't think it will have much of a negative impact.
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#1655 by zellerium on 26 Apr, 2016 18:33
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In lieu of a custom waveguide, I am considering using the waveguide that was mounted in the microwave. I think I can mount this fairly easily to the wedge geometry since it has flat side-walls. That little bump out will be inside the cavity, but I don't think it will have much of a negative impact.
That's what we used, it seemed to work well. However the white paint is non-conductive and arcing occured until we sanded off enough to make electrical connection with the cavity. -
#1656 by X_RaY on 26 Apr, 2016 18:43
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It may be a better solution to integrate metallic tuning rods into the first cavity to get impedance match. This of course costs a bit of microwave power, also the additive filter cavities due to eddy currents at the inner surfaces, but it narrows the local bandwidth in the EMDrive main cavity.Hey Monomorphic,
That waveguide orientation is going to excite a TM mode in your wedge, correct? Do you have any reasoning behind this decision?
Also, have you considered using any sort of matched load similar to Yang?
High power ferrite circulators (what I believe Yang used) are probably not within any DIY budget, but with your FEKO experience I would bet you could devise a narrow band accepting aperture on the frustum side and a wideband matched load on the other side of the waveguide.
I wonder where the tradeoff of power into the cavity vs quality of resonance would be optimized for a magnetron.
I greatly admire all the work you've been doing! Thanks for posting
Thank you for the kind words!
I've been running sims on the waveguide today and noticed the TM mode excitation. Have already changed the orientation back to TE.
Didn't X_Ray also talk about a narrow band accepting aperture recently? He called it a periodic bandpassfilter.
Ah yes, that definitely looks like an elegant solution. I guess the trick would be sizing everything so that the intermediate cavities can dissipate enough heat to withstand deformation to maintain their resonant properties. I'd be afraid of the first cavity rejecting too much back to the magnetron. Maybe some absorbtive load inside could mitigate that effect?
The biggest issue would be the measurement of VSWR or even S-parameter in this configuration including the magnetron.
Against the thermal problems one could use materials with very small thermal expansion coefficient with a thin copper,silver or gold layer.
edit
Some kind of isolator circuit (circulator & load) should be work to protect the magnetron against overheating. -
#1657 by CW on 26 Apr, 2016 19:16
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Question to the HF gurus:
If spectral variation and sort of wandering bandwidths are a problem for reliable and stable mode shaping, then I wonder if there is a way to model and build a very narrow bandwidth 'pre-filter' wave guide that eats the poluted spectrum of an off-the-shelf magnetron and only then feeds the cleared narrow bandwidth spectrum with stable center frequency into an EM drive cavity?
BR
CW -
#1658 by SeeShells on 26 Apr, 2016 19:21
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In lieu of a custom waveguide, I am considering using the waveguide that was mounted in the microwave. I think I can mount this fairly easily to the wedge geometry since it has flat side-walls. That little bump out will be inside the cavity, but I don't think it will have much of a negative impact.
On for a bit but although I wanted to comment about monomorphic's build. Nice thinking out of the box and great work.
I loved the idea of using the microwave launcher. It does work well.
Shell
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#1659 by X_RaY on 26 Apr, 2016 19:26
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Question to the HF gurus:
That's exactly the idea behind the prefilter structure. The output of the filter will be several dB lower than the noisy magnetron source alone but with smaller BW.
If spectral variation and sort of wandering bandwidths are a problem for reliable and stable mode shaping, then I wonder if there is a way to model and build a very narrow bandwidth 'pre-filter' wave guide that eats the poluted spectrum of an off-the-shelf magnetron and only then feeds the cleared narrow bandwidth spectrum with stable center frequency into an EM drive cavity?
BR
CW
It works. It is standard technique.
http://tinyurl.com/z7b4lam
http://www.2comu.com/showroom_waveguide_filter.html
http://www.smtconsultancies.co.uk/products/rtcc/rtcc.php
