-
#320 by rfmwguy on 17 Dec, 2015 20:54
-
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force? -
#321 by glennfish on 17 Dec, 2015 20:55
-
Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
To me it's an issue of, given a frustum mag orientation, we need to develop a model of the thrust behavior which includes all the balloons, lorenz forces, air flows, and maybe a modicum of EMDrive. Get enough data to derive a function that looks like:
displacementaka thrust = function(power on time)orientation
Wrap some standard deviations around that for orientation up and orientation down
It's a numbers game statistically. Run enough samples until either the standard deviations no longer overlap, or until you realize you don't have time to do enough runs.
To me, it doesn't matter how many confounding error sources there are, as long as they are always there and consistent. Thrust with orientation up will be the same as thrust with orientation down if and only if there is no thrust, all other things being equal. If there is thrust within the limits of your measurement devices, it will emerge statistically at some point. If there isn't, or it isn't within the limits of your measurement devices, it will not.
The debate then would become, were all other things equal. -
#322 by lmbfan on 17 Dec, 2015 21:05
-
Great discussions...yes, my mag temp idled between 150 and 170 degrees C depending on whether it was 30% or 50% power cycle respectively. 100% power for long duration was not measured on the original mag, but another pullout mag I tested got to 200 deg C quickly at 100% power. Thus confirmed my concern that getting a "matched" set of mags (one on each side of the balance beam) would be difficult...they're just not built precise enough.
Here's a simple test somebody can plug into some software...imagine a 4 inch square metallic box with 2 opposite sides open (vertical sides).
Heat the thing to 170 degrees C from a CENTRAL point within the box, conducting heat to the remaining walls via air convection and direct mechanical attachment.
Ambient air was 28 degrees C and humidity was about 56% in the tests I ran within a few days of each other.
The metal was galvanized steel. It is safe to assume 14 gauge steel or 0.0677 inches thick on 4 sides (5 & 6 are open). The weight was 750 mg (magnetron alone).
For those wishing to dig deeper, the non-hermetic box on top is about 3 inches tall and 3.75 inches square...made of the same material.
Below is a cropped image someone sent me of my mag, suggesting a heatsink idea.
These simple details should be enough to quantify the amount of vertical lift component (perhaps not turbulence).
Are we talking millinewtons? micronewtons? How similar is this to the 40 or so micronewtons of horizontal (torsional) Lorentz force? Remember vertical Lorentz force was not measured nor estimated in Mr Li's paper.
Please find attached a simple model of the above in the common IGES format. I'd think that adding some type of thermal mass to the center of the housing would be advisable, seeing as how there is a lot more geometry here than the outer housing. This is NOT a simulation of any kind, this is just a model I make available to anyone who has the knowhow to do a simulation. If I have some spare time later, I might be able to run an extremely simple thermal analysis, but as I have never attempted one before, I would not know if it was set up properly.
Added: 2" hole on the bottom of the top piece, .5"X1.5" hole on the side of the top piece for connector.
If these are harmful to the model, I can remove them easily, I can also add any other simple features. I can also export the model in STEP or STL format if necessary. Rename "mag_asm.txt" to "mag_asm.igs" (IGES files are plain text).
-
#323 by SeeShells on 17 Dec, 2015 21:09
-
Throwing this out there for discussion.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convection effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured. If the sample population was representative of the true statistical population (which was NOT shown), the statistical test may be only showing the effect of transient thermal natural convection effects.
rfmwguy I'd consider a heat lamp ~250w http://www.acehardware.com/product/index.jsp?productId=35077376
Mount it pointing down a couple of inches from where your magnetron would be facing the frustum endplate. Monitor the thermal rise in temp, and the lift over time with your digital distance hardware and plot it.
I'm down for a few days... Dr's orders so I'll not be posting much but HAD to reply to this.
Shell -
#324 by Rodal on 17 Dec, 2015 21:11
-
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
Take a gander at this: http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459128#msg1459128
There is no constant, rising plume of thermal lift from a hot cup of coffee. There is no constant, rising plume of thermal lift from your test either. It is time dependent, due to vortex shedding fluid dynamics effects.
When you turn the magnetron on and off you superimpose additional transient thermal convection effects that disturb a damped balance that was previously subject to transient thermal convection. One cannot account for the additional effects of turning the magnetron ON and OFF, simply linearly, because the problem you are dealing with (thermal convection) is nonlinear. The effect of turning the magnetron ON may be counterintuitive, if one does not visualize what is happening to the air flow when you are turning the magnetron ON.
I find it noteworthy that the effect you are showing is statistical: it is NOT present every time the magnetron goes on. This statistical nature leads to me to think that it is due to natural convection air flow.
-
#325 by Rodal on 17 Dec, 2015 21:48
-
I answered your question. Now a QUESTION for you
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
:
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force, under the same identical test configuration, during the same overall test?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
(my answer is that this is due to transient thermal convection effects on the teeter totter balance)
-
#326 by Flyby on 17 Dec, 2015 22:29
-
.....
A few weeks ago, I used those Yang plots to determine the efficiency of her EMdrive while the input power increased.
2) The experimental results of Prof. Yang showed strong nonlinearity between the measured force and the input power (see attached chart). Prof. Yang's experiments show diminishing returns (actually slight decrease in measured forces for input power exceeding 300 Watts and general flat response) for increasing input power.
Hence it does not follow that the thermal artifacts will scale linearly in experiments conducted at much higher input power. On the contrary, Prof. Yang's experimental results show strong nonlinearity, with the touted "EM Drive" force dependence on input power effectively dissappearing after about 300 watts, the dependence looks practically flat at input powers greater than 300 W. The nonlinearity of the "force" vs. input power experimental relation of Prof. Yang has not yet been scientifically modeled hence its nature can only be speculated until a verifiable model is demonstrated.
This shows that if anything, experiments conducted at ambient conditions with low power may be highly misleading and NOT linearly scalable to higher powers, just as it would be highly misleading to conflate the flight of an insect with the flight of an airplane (the aerodynamics are completely different at very low Reynolds numbers).(The range of Reynolds number in insect flight is about 10 to 10^4, which lies in between the two limits that are convenient for theories that try to simplify the nonlinearity of Navier Stokes fluid dynamics: inviscid steady flows around an airplane's airfoil and Stokes flow experienced by a swimming bacterium. For this reason, this intermediate Reynolds number range used by insects in their flight is not as well understood as the high Reynolds number regime for airplanes. )
What I did is to bring all generated forces back to 1kW of power to get an idea how her frustum performed while she gradually increased the power...
It didn't show a straight linear relation, but a steep decline in efficiency at first, then leveled out for a long period and at the end showed improvement again, which might hint that a drastic increase in power "might" yield better then expected results.
I find it puzzling to why it stayed almost completely level from around 800W up to 2200W...
The performance degrading from 300W to 700W is probably due to thermal effects?
added:
to eliminate yang's individual test variations I averaged the force results (blue line) to get a single value.
-
#327 by OnlyMe on 17 Dec, 2015 22:31
-
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
A QUESTION for you:
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
The EMDrive wiki says Berca had at least two inconclusive tests before a successful test. So not every time.
Shawyer, I am sure did not always get results he published and has been at it for how many decades?
Yang had a lab and working group and it seems funding, but it doesn't really say how many failures might have Preceded the success she claims.
Eagleworks also played around a bit. How many frustums? Seems Paul implied more than one which would seem to suggest not all were successful.
Why did rfmwguy's experiment fall on the low side of repeatable results? A very low Q? To start and novel approach with the mesh.., and did he not mention that when he added the tuning rings the resonance or Q improved by, what double? But I don't think he reran the tests at that point.
Tajmar, for one seems inconclusive based on design and was not looking for thrust. "Direct Thrust Measurements of an EM Drive and Evaluation of Possible Side-Effects". I could very well be mistaken but I understood his purpose was to try and find ways to address thermal and systemic issues... Hence putting the frustum in an insulated boxe filled with fiber glass to reduce or eliminate thermally induced convection noise.
I believe you are attempting to hold DIY low budget projects to standards even some labs would have difficulty with.
Was what rfmwguy saw thrust that cannot be accounted for as thermal, impossible to say from where either of us sit.., without independently retesting his whole system. As I have said a few times to get out of the noise I believe the DIY experiments are going to need at least double digit mN of thrust... I thought that is essentially where rfmwguy said he was aiming for in 2016. Low double digits.
-
#328 by Rodal on 17 Dec, 2015 22:49
-
Berca's previous null tests had a different configuration, and experimental setup.
Berca's tests with identical test configuration were reproducible.
Paul March already addressed in previous threads that he had no test (with a dielectric, and mode shape TM212) resulting in no thrust. -
#329 by oliverio on 17 Dec, 2015 23:12
-
Might I ask why no one has suggested just putting the frustrum in a sealed box, then heating the box to very high heats. If my understanding is correct, the sorts of flow dynamics discussed here should be gone in a closed system heated to 200 degrees Celsius. There is no way the frustrum could heat the air enough (relatively speaking) to cause significant thermal lift.
-
#330 by SeeShells on 17 Dec, 2015 23:36
-
Doc, while it was not consistent each time, its easy to see from the video of the mag spectrum that its own rf stability is more likely the cause rather than a transient thermal natural convection effect, which I am trying to understand what you mean here.Whatever we work out, I'm at a point where DIY experimentation may not be worthwhile unless we can figure a way to characterize thermal dynamics.
From my perspective, I knew there was lift, what I was looking for was an interruption of it during mag on conditions. I believe I saw this clearly as either attenuation, reversal or a hold of the lift progression.
Remember, the thermal mass of the magnetron assembly does not permit instantaneous heating or cooling. If you look at the thermal videos, you see it is quite gradual...much slower than the instantaneous changes to the thermal lift profile I observed when mag switched between on and off, so my posit is that quick changes to a lift profile CANNOT be due to instantaneous heating or cooling at mag transition.
Where am I off base here?
Your experiments do NOT show that effect consistently with every ON and OFF turning of the magnetron: the thermal lift profile observed when magnetron was switched on and off was not the same through time You had to appeal to statistics to arrive at a conclusion. The statistics are based on a small sample population hence questionable from a statistical viewpoint.
Physically, the effect you observed may be due to transient thermal natural convection. There was no analysis of the transient thermal natural convectin effect in your experiment (due to the hot magnetron sitting on top of the upper plate of the EM Drive). Transient thermal natural convection effects will result in statistical-looking effects like the one you measured.
Remember, the displacement was downward (against lift), not upwards during mag-on at a higher occurance over the 2000 or so data points. Your suggestion seems to imply vertical (upward) jetting which I cannot visualize in my test. The rising plume of thermals should (if I understand basic fluid dynamics) impose an upwards lift, not a downward force.
Is there something you can point me to help me understand an opposite effect of what I am thinking? i.e. a rising, thermal plume causing a downwards force?
A QUESTION for you:
Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
The EMDrive wiki says Berca had at least two inconclusive tests before a successful test. So not every time.
Shawyer, I am sure did not always get results he published and has been at it for how many decades?
Yang had a lab and working group and it seems funding, but it doesn't really say how many failures might have Preceded the success she claims.
Eagleworks also played around a bit. How many frustums? Seems Paul implied more than one which would seem to suggest not all were successful.
Why did rfmwguy's experiment fall on the low side of repeatable results? A very low Q? To start and novel approach with the mesh.., and did he not mention that when he added the tuning rings the resonance or Q improved by, what double? But I don't think he reran the tests at that point.
Tajmar, for one seems inconclusive based on design and was not looking for thrust. "Direct Thrust Measurements of an EM Drive and Evaluation of Possible Side-Effects". I could very well be mistaken but I understood his purpose was to try and find ways to address thermal and systemic issues... Hence putting the frustum in an insulated boxe filled with fiber glass to reduce or eliminate thermally induced convection noise.
I believe you are attempting to hold DIY low budget projects to standards even some labs would have difficulty with.
Was what rfmwguy saw thrust that cannot be accounted for as thermal, impossible to say from where either of us sit.., without independently retesting his whole system. As I have said a few times to get out of the noise I believe the DIY experiments are going to need at least double digit mN of thrust... I thought that is essentially where rfmwguy said he was aiming for in 2016. Low double digits.
Berca's previous null tests had a different configuration, and experimental setup.
Berca's tests with identical test configuration were reproducible.
Paul March already addressed in previous threads that he had no test (with a dielectric, and mode shape TM212) resulting in no thrust.
What we are discussing about RFMGUY's test is not that he had different results with different tests. What we are discussing is that he measured different results during the same identical test, when turning the magnetron on at different times.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, but never one of showing no force when the RF was turned on. NASA's measurements showed that an experimental force trace measurement every time that the RF was turned on during the same test.
I would propose that due to the nature of rfmwguy's magnetron setup and his power supply driving it he could be unsure if the output of the magnetron was exciting anything in the frustum from run to run.
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1449178#msg1449178
Even after he did a modification to the magnetron to increase stability the Spectrum Analyzer still showed splatter and AM modulation all around the center tune frequency of the frustum.
Simply because of the splatter and AM modulation of the RF from the magnetron you could never be sure of a "lock" into a mode that might lead to thrust.
Shell -
#331 by rfmwguy on 18 Dec, 2015 00:13
-
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year. -
#332 by oliverio on 18 Dec, 2015 00:13
-
One question for you theoretical physicists, since my intuitions break down at the level of particle-wave duality.
I know it to be the case analytically that inside a resonant cavity, there exists a standing wave that will sometimes migrate too. Of course it cannot be the case that the energy itself is moving with the same velocity as the wavefront, because it would imply nearly stationary photons. Instead I assume I should conceive of this resonant cavity as containing an oscillating field rather than a set of bouncing quasiparticles.
However, that said, I have a new question: if one were measuring discrete points of this resonant field, would the energy density of the oscillating field be varying at the speed of light still? I.e. should I conceive of the resonant waveform as "one big phota" (pardon the pun) bouncing back and forth? Pardon the crude analogy, but a bit like a piece of jell-o being oscillated? -
#333 by Rodal on 18 Dec, 2015 00:19
-
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
What we are discussing is not that there were different results with different tests. What we are discussing is that it shows different results (including NO "anomalous force") , when turning the magnetron on at different times, during the same identical test.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, and different shapes of the force trace, but never one of showing no force when the RF was turned on. NASA's measurements showed an experimental force trace measurement every time that the RF was turned on during the same test.So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles.
A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
The following tests were suggested:
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459176#msg1459176
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459173#msg1459173
to show that there is an anomalous force in your tests that cannot be explained by transient thermal convection effects.
If interested in this you have to attempt to carry out the tests previously described, with the magnetron heated (ON and OFF) but not having RF going into the cavity.
If interested in understanding the fluid dynamic and lifting effects you have to take Schlerein optical videos to see what is actually happening when you are turning the magnetron on,and off, instead of assuming what is going on, based on intuition.
Either that or:
1) test in a vacuum, and hence eliminate all thermal convection effects
2) move the magnetron out of the way, and have RF coming into the cavity symmetrically as proposed by Shell.
I understand that you are saying that the effect is due to RF going into the cavity. I find that evidence lacking when you don't have tests conducted with the magnetron heated (ON and OFF) and no RF going into the cavity.
If you have the interest, it would be revealing at least to do the tests proposed with a heated magnetron (ON and OFF) without RF going into the cavity, to show that the effect is related to RF going into the cavity.
-
#334 by rfmwguy on 18 Dec, 2015 00:44
-
I left that determination up to a professional statistician. I did not get that pronouncement from them.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
What we are discussing about your test is not that it had different results with different tests. What we are discussing is that it shows different results (including NO "anomalous force") , when turning the magnetron on at different times, during the same identical test.
Paul March has many tests were he shows the experimental measurement vs time. There is not a single such trace showing Paul March's results during the same test where he would get no experimental force when turning the RF on. The issue with NASA's test was one of drift of the baseline, and different shapes of the force trace, but never one of showing no force when the RF was turned on. NASA's measurements showed an experimental force trace measurement every time that the RF was turned on during the same test.So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles.
A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
We have a disagreement here. I have no problem with that. To convince me otherwise, I will need data that demonstrates the possibility of triple digit micronewton force generation in a vertical axis. Lorentz is out. If you have another specific error source in mind, lets hear it. Point me to some examples. My eyes and mind are open. -
#335 by Rodal on 18 Dec, 2015 00:50
-
...A statistical analysis is unconvincing (and therefore not straightforward) for your tests because the sample population in your tests is way too small to arrive at a conclusion that your sample population is representative of the true statistical population, nor is the sample population large enough to determine what is the appropriate statistical distribution for a parametric test.
I left that determination up to a professional statistician. I did not get that pronouncement from them.
We have a disagreement here. I have no problem with that. ...
I have not seen a statistical argument in these threads disagreeing with the fact that the sample population in your tests is way too small (to arrive at a conclusion that your sample population is representative of the true statistical population). Therefore I have not seen a justification that you can use only statistical tests to arrive at a robust statistical conclusion based on your test results.
PS: I am a member of the American Statistical Association, and use statistical models (as well as information theory) to make a living.
-
#336 by Tetrakis on 18 Dec, 2015 00:56
-
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
I think 100mg in such a large, hot setup in air is at least in the ballpark of thermal convection forces. Simply opening the doors of a milligram balance can throw it off by about ten milligrams. As I said about 150 pages ago in this thread, such a small force can't really be considered a positive result. You have two effects, poorly characterized air currents and "the EMDrive effect" (Or, as some troublingly refer to it, "Thrust"), but without either high vacuum or, as you aim to achieve, large forces, you can't convincingly disentangle them. You are right that characterizing these thermal effects would be like chasing phantoms, and this is exactly why any statistically significant values you obtain are suspect.
If you want to answer your question about whether or not the EMdrive works, you should do what you propose: design a better, more robust experiment with a higher expected S/N ratio. But just as importantly, you need to define a null hypothesis before you carry out that experiment. If you continue your tests with this better device, what evidence would indicate that it doesn't work? -
#337 by OnlyMe on 18 Dec, 2015 01:04
-
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... No warrantee how long the magnetron could handle it.
PS it would probably work better for a solid copper frustum where each of the three pieces could have a separately cast part and there would hopefully be a larger thrust signal to work with. -
#338 by oliverio on 18 Dec, 2015 01:13
-
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and a provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... Not warrantee how long the magnetron could handle it.
At this rate why not just pack the box with sand? Its specific heat is large I believe, and intuition tells me that a very hot object inside a box of sand will be cool to the touch after some massive internal heat flux. -
#339 by OnlyMe on 18 Dec, 2015 01:15
-
Q) Why is yours the first (and only) EM Drive test I know of that has to appeal to statistics to show an EM Drive force?
A) 1) Simplicity. Comparison between displacement track of beam with mag ON versus mag OFF. Lift track upwards was smooth/relatively linear and without stickiness during mag OFF (as heating started). 2) Lack of anyone willing to perform an analysis of thermal plumes or other potential error sources, including Lorentz force other than the horizontal vector; not applicable my tests imho.
Q) Am I correct that all the other tests (by Shawyer, Yang, NASA, Tajmar, Berca, etc.) claim that the EM Drive thrust in their tests is a reproducible effect, every time that the RF is turned on?
A) Not to my knowledge. All had several tests without measureable results.
Q) What (in your opinion) is responsible for the statistical nature of your tests, such that sometimes turning the magnetron ON had no measurable effect?
A) The use of a standard magnetron and (poorly filtered) power supply (in which I demonstrated afterwards with a spec an) did not always provide an instant, stable lock or frequency in comparison to lower power solid state sources or filtered power supplies. In addition, my VNA sweep of the frustum afterwards showed that frustum resonance was below average mag frequency.
As someone else said, I had planned to move to Phase II testing in 2016 with a goal of double-digit millinewton displacement numbers as compared to 177 micronewtons. This was also discussed here while you were away.
Unless someone demonstrates or points out a potential error source that approaches a triple-digit micronewton level, I will not chase those phantoms. Lorentz force in the horizontal axis falls into this category as does thermal plume turbulence (fluid analysis), imho. Show me a non-jet down force test result or example and I may take that off of my phantom list. There were no jets identified on the top plate emanating from the mag per my thermal scans, nor was there uneven heating of any of the outer surfaces; a clear sign of air jets.
So, statistics are most straight-forward way to analyze beam displacement variances between mag on and mag off cycles. No other error source hypothesis approaches the force level needed to interrupt the thermal lift track; Lorentz, air jets, plume turbulence, thermal expansion, etc., etc.
If anyone has other ideas...I'm all ears and will test for them if funding allows next year.
If you can isolate the current frustum in a outer can essentially, the whole device could be encased in a cast high temperature resistant material. Preferably in separate sections so it could be disassembled without destruction. Weight should not real be a problem for the balance beam. The outer thermally resistant casting should slow down any exterior convection based thermal effects and by controlling the shape make modeling what exterior thermal effects there are easier to model. The outer cast material can also be sealed to eliminate out gassing and any ballooning, and being ridged resolve ballooning.
Casting material that can stand 2600-3000 degrees F is available.
You would have to tune the frustum and then seal the final portion of the casing..., preventing any additional tuning.
The material I was thinking of is normally used in making forges. It is ridged and depending on how thick the casting is would act as a thermal barrier and heat sink initially and a provide more uniform heat dispation as it heats up. This material should be able to handle even the magnetron at 100%... Not warrantee how long the magnetron could handle it.
At this rate why not just pack the box with sand? Its specific heat is large I believe, and intuition tells me that a very hot object inside a box of sand will be cool to the touch after some massive internal heat flux.
The current frustum is made of a wire mesh.
... And I am unsure how the magnetron would react to being packed in sand.
: