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#3720 by xyzzy on 10 Jul, 2016 18:21
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Using Roger's force equation we get (2 × 10,000Qu x 0.4886Df x 900Pwr) / 299,700,000c = 29mN. Dave's best result 18.4mN.
Please be careful with those numbers. The power levels may be difficult to compare.
Roger's equation likely assumes only the net microwave power losslessly and reflectionlessly injected into the cavity. The 900 W (as stated) may however be a completely different kettle of fish.
Since I can't remember it being stated otherwise, I'll assume it also likely contains various losses:
- to the transformer magnetization (core losses)
- to the windings and wires (I2R losses)
- to the filament (some 30 W, give or take a dozen)
- to the finite efficiency of microwave generation process in the magnetron itself
- to the thermal losses in the magnetron metallic structure and antenna lead
- to the reflection due to the antenna mismatch (power that does not get radiated inside the cavity)
- to the transmission back into the magnetron (the antenna works both ways - receives and transmits)
- to imprecise frequency lock (the magnetron is being pulled away from its natural resonant frequency)
- possibly to remaining spectral components that are off-center and thus do not form resonance
All this is enough to cause a lot of losses. My guess would be 50 to 60 % at the least, likely even more.
The 18.4 mN can also include other components (such as thermo-mechanical) as well as a possible peak (overshoot) from an under-damped dynamic response of the system, making the underlying force less than that.
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#3721 by TheTraveller on 10 Jul, 2016 18:58
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Using Roger's force equation we get (2 × 10,000Qu x 0.4886Df x 900Pwr) / 299,700,000c = 29mN. Dave's best result 18.4mN.
Please be careful with those numbers. The power levels may be difficult to compare.
Roger's equation likely assumes only the net microwave power losslessly and reflectionlessly injected into the cavity. The 900 W (as stated) may however be a completely different kettle of fish.
Since I can't remember it being stated otherwise, I'll assume it also likely contains various losses:
- to the transformer magnetization (core losses)
- to the windings and wires (I2R losses)
- to the filament (some 30 W, give or take a dozen)
- to the finite efficiency of microwave generation process in the magnetron itself
- to the thermal losses in the magnetron metallic structure and antenna lead
- to the reflection due to the antenna mismatch (power that does not get radiated inside the cavity)
- to the transmission back into the magnetron (the antenna works both ways - receives and transmits)
- to imprecise frequency lock (the magnetron is being pulled away from its natural resonant frequency)
- possibly to remaining spectral components that are off-center and thus do not form resonance
All this is enough to cause a lot of losses. My guess would be 50 to 60 % at the least, likely even more.
The 18.4 mN can also include other components (such as thermo-mechanical) as well as a possible peak (overshoot) from an under-damped dynamic response of the system, making the underlying force less than that.
Of course the equations power is the forward power, which as you suggest will be less than 900Wrf.
Also remember there is an oil damper which will turn some of the torque generated my Dave's EmDrive into heat in the oil. That energy is not returned as the power is cut and the stored energy in the wire is released, some of which also ends up heating the oil.
The lever arm of the EmDrive to the oil damper is very much longer than the lever arm of the torsion wire to the oil damper. So the system is not symmetrical.
Then remember the oil damper is off axis from the tension wire, resulting in an off axis centre of resistance. Have advised Dave the oil damper needs to operate in line with the torsion wire twist and untwist to ensure a symmertical treatment of the wire twist and untwist. -
#3722 by xyzzy on 10 Jul, 2016 18:59
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It seems to me that for Dave and perhaps you, that using a Lipo battery to drive the heater circuit would be an easy way to eliminate the heater wire heating issues that Dave is facing without having to deal with the much larger power requirements of the HV circuit. Since the heater circuit is switched off once the maggie gets operating, the total AH required wouldn't be that high.
...
Very good idea! That would finally allow to get rid of those pesky 10 amperes going over the wires (without having to use a monster sized battery to pull the full kW out of). Anode current is only some 300 mA by comparison, so if only the anode current is left remaining, the wire influence should decrease a lot.
It would also reduce the number of required wires from 3 to 2 (GND and -HV), which would make the use of a coaxial cable possible (a symmetrically built cable would cause very few external side effects, whether they be lorentz or thermo-mechanical in nature).
However, caution should be exercised around lithium batteries. A magnetron can (and does) leak quite a lot of stray RF out via the filament, and the inductors in the base don't remove all. Stray RF can get rectified across chemical barriers in a battery and (if it's too high) can cause damage. Lithium batteries in particular are not known for being chemically stable, and if you blast them with a magnetron (there are some youtube videos around), they apparently like to explode and catch fire.
Instead, I would consider the use of 3 NiMH (or even NiCd) cells in series to be more preferable. A filament only needs some 30 W, and that can be provided by the more conventional batteries too - without having to use lithium. The old style NiCd are still available from some specialty shops because they have some long-lived legacy industrial applications, and of course there are many more modern NiMH cells around - with highly improved capacities compared to the old NiCd days.
Non-lithium batteries tend to be more robust and, compared to lithium chemistries, much less likely to explode violently while sprouting flames and discharging heavily toxic gases.
There have been people who involuntarily witnessed a lithium battery explosion indoors in a small room, and while the direct effects of the explosion and fire were nothing to sneeze at, the toxicity of the gases ended up being a big medical problem, taking months to years to "heal" and never fully going away.
Safety first! No need to risk your lives and health! -
#3723 by Monomorphic on 10 Jul, 2016 19:58
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Houston, we are GO.
After a couple weeks downtime so I could improve the test rig, I am now ready to begin powered testing again. I was running into some thermal plume issues with the magnetron mounted beneath the emdrive, so I moved it back to the side. I also removed the old blue laser since it is redundant with the new Omron laser displacement sensor.
I worked some on the harness for the power leads. And I doubled the size of the oil dampening paddle.
Also included a screen shot of the latest 'tap' calibration test. The first bump simulates forward thrust, the second reverse thrust. I think I have a very well dampened system here.
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#3724 by WarpTech on 10 Jul, 2016 20:25
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Houston, we are GO.
After a couple weeks downtime so I could improve the test rig, I am now ready to begin powered testing again. I was running into some thermal plume issues with the magnetron mounted beneath the emdrive, so I moved it back to the side. I also removed the old blue laser since it is redundant with the new Omron laser displacement sensor.
I worked some on the harness for the power leads. And I doubled the size of the oil dampening paddle.
Also included a screen shot of the latest 'tap' calibration test. The first bump simulates forward thrust, the second reverse thrust. I think I have a very well dampened system here.
Maybe a little too much damping, but nice job! We wouldn't want anyone confusing the slow decay for thermal cooling. -
#3725 by Monomorphic on 10 Jul, 2016 20:41
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Maybe a little too much damping, but nice job! We wouldn't want anyone confusing the slow decay for thermal cooling.
I agree there may be just a little too much dampening.
I'm using very heavy weight oil. I can switch to a lighter weight or change out the paddle for something smaller. The original paddle was 3 inches. This one is 6 inches. Perhaps a 4.5 inch paddle would work better. Very easy to switch it out.
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#3726 by TheTraveller on 10 Jul, 2016 21:34
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Seems where was some confusion on Dave's frustum dimensions.
I originally used 6.25 Small Dia, 10.0 Big Dia, 8.1 Length which gave me a TM013 resonance of 2.459GHz.
Seems the actual length was 8.175, which drops the TM013 resonance to 2.452GHz or 11MHz higher than Dave's measured 2.441GHz.
I'm happy with that.
BTW Dave has altered the position of his oil damper to be in line with the torsion wire, as attached, plus the altered power cabling has eliminated the heater current anomaly with the faulty maggie. Dave informs that a new maggie has been ordered.
My spreadsheet TM013 resonance data for Dave's frustum is attached.
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#3727 by Rodal on 10 Jul, 2016 22:29
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Seems where was some confusion on Dave's frustum dimensions.
I originally used 6.25 Small Dia, 10.0 Big Dia, 8.1 Length which gave me a TM013 resonance of 4.65GHz.
Seems the actual length was 8.175, which drops the TM013 resonance to 2.452GHz or 11MHz higher than Dave's measured 2.441GHz.
I'm happy with that.
...
I'm not happy with that: it looks like you have a typo in there, when you wrote (bold added for emphasis):which gave me a TM013 resonance of 4.65GHz
TM013 for those dimensions cannot have a resonant frequency exceeding 4.6 GHz and changing the length from 8.1 to 8.175 (less than 1% difference) cannot change the resonant frequency from 4.65GHz to 2.452GHz (190% change)
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#3728 by TheTraveller on 10 Jul, 2016 23:01
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Seems where was some confusion on Dave's frustum dimensions.
I originally used 6.25 Small Dia, 10.0 Big Dia, 8.1 Length which gave me a TM013 resonance of 4.65GHz.
Seems the actual length was 8.175, which drops the TM013 resonance to 2.452GHz or 11MHz higher than Dave's measured 2.441GHz.
I'm happy with that.
...
I'm not happy with that: it looks like you have a typo in there, when you wrote (bold added for emphasis):which gave me a TM013 resonance of 4.65GHz
TM013 for those dimensions cannot have a resonant frequency exceeding 4.6 GHz and changing the length from 8.1 to 8.175 (less than 1% difference) cannot change the resonant frequency from 4.65GHz to 2.452GHz (190% change)
Typo. 2.459GHz. Modified the original post.
Thanks for the sharp eye
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#3729 by Monomorphic on 10 Jul, 2016 23:40
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Maybe a little too much damping, but nice job! We wouldn't want anyone confusing the slow decay for thermal cooling.
Looks like the 4.5" paddle was the way to go. Here are four (4) tap tests. Two forward thrust taps and 2 reverse thrust taps. Return to center happens much more quickly.
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#3730 by zellerium on 11 Jul, 2016 00:21
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Hi all,
Finally closing off the EM Drive experiment we did at Cal Poly. In case you hadn't heard, observed deflections appeared to be caused purely by thermal effects. Removing the hose clamp securing the wires to the cylinder caused deflections to change in unpredictable patterns leading us to believe that thermal expansion of the leads was the only cause of pendulum deflection.
Some possible reasons our cylindrical resonator didn't work:
Asymmetry was not large enough (1 inch thick dielectric disc in ~7 inch by 4.25 in diameter cavity)
Quality of the resonator may not have been high enough
Force measurement resolution wasn't high enough
But at least we learned a lot and had fun doing it. I'll probably try again someday soon when I have the resources.
Attached is the final paper, all corresponding appendices can be found on my LinkedIn profile: https://www.linkedin.com/in/kurtwadezeller
Thank you to everyone for your support and efforts toward the EM Drive!
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#3731 by FattyLumpkin on 11 Jul, 2016 00:56
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Warp Tech's report re EWL paper is troubling: My studies are taking me far and wide in research of the literature, and although unsubstantiated rumors re a probable FOIA filing are beginning to surface. Are these rumors new? I don't recall having ever seen any mention of them in previous NSF strings/postings et al. (before). If someone does file a FOIA for disclosure of the EWL paper now in review, could it create some sort of "clamp down"? I know nothing about the intricacies the FOIA law in this regard. M McCullough said release of the paper was imminent? What to think? Thoughs about this folks?
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#3732 by zen-in on 11 Jul, 2016 02:03
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Warp Tech's report re EWL paper is troubling: My studies are taking me far and wide in research of the literature, and although unsubstantiated rumors re a probable FOIA filing are beginning to surface. Are these rumors new? I don't recall having ever seen any mention of them in previous NSF strings/postings et al. (before). If someone does file a FOIA for disclosure of the EWL paper now in review, could it create some sort of "clamp down"? I know nothing about the intricacies the FOIA law in this regard. M McCullough said release of the paper was imminent? What to think? Thoughs about this folks?
What is an unsubstantiated rumor? Is it a possible rumor that some unknown person said they might have heard? Whatever it is it has nothing to do with space related uses of em drives and experiments to validate or understand the alleged effect; which is what this forum is for. -
#3733 by masterharper1082 on 11 Jul, 2016 02:39
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Has anyone seen this paper? Any theory that seems to reconcile dark energy and dark matter, and can create mass has my interest...
https://www.google.com/url?sa=t&source=web&rct=j&url=http://math.mit.edu/~huncheng/Weyla.pdf&ved=0ahUKEwiXuduEnurNAhWB54MKHR_AC7gQFggvMAU&usg=AFQjCNHRXdXfHYkwmSvAeYOZUIsLaaxCFA&sig2=0r9rrxEJRjMVxlS0fTv50w
The last sentence, in particular, is intriguing...
"It is interesting to ponder if there are ways to observe the S particles if
they exist in nature."
Have we created an S-particle manipulation device? -
#3734 by Star One on 11 Jul, 2016 06:25
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Does anyone know the status of the new paper by White and March?
No
I just received the paper Dr. White published in September. A Discussion on Characteristics of the Quantum Vacuum, published in Physics Essays, Sept. 2015. http://physicsessays.org/browse-journal-2/product/1396-11-harold-sonny-white-a-discussion-on-characteristics-of-the-quantum-vacuum.html
It's not what you're looking for but I found it to be a very inspiring read. I'm currently working on a response to this discussion.
Last I heard, after several re-writes of their copper frustum in-vacuum paper, there is no hope in sight of getting it past the peer reviewers for the Journal in question. Not much else going on, due to budget cuts. It sounds like any work being done is on their own time.
So are you saying that funding for their work has been cut?
So there is no desire to publish it. Easy as that. Only thing they can do is try to publish it without official approaval, which they will of course will not do.
Thanks. So that's the end of that then. Pretty downbeat ending to the whole enterprise. -
#3735 by DaCunha on 11 Jul, 2016 10:42
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Thanks. So that's the end of that then. Pretty downbeat ending to the whole enterprise.
Hard to accept...
but if so the Referees and Nasa must have had a reason for their decisions. I am quite sure by now that the concept is not working as we
expected it to work.
The Thing is: If an Experiment shows negative results (though scientifically constructive and in this sense positive) These results are never published nowadays.
So no News from Eagleworks means, that the EMDrive concept probably does not work, meaning that the thrust could not be measured in their improved Setup.
However, there are many more experimental ideas to test, so I am not losing my confidence, that at least the solar system will be colonized sometime. -
#3736 by Rodal on 11 Jul, 2016 11:52
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Thanks. So that's the end of that then. Pretty downbeat ending to the whole enterprise.
Hard to accept...
but if so the Referees and Nasa must have had a reason for their decisions. I am quite sure by now that the concept is not working as we
expected it to work.
The Thing is: If an Experiment shows negative results (though scientifically constructive and in this sense positive) These results are never published nowadays.
So no News from Eagleworks means, that the EMDrive concept probably does not work, meaning that the thrust could not be measured in their improved Setup.
However, there are many more experimental ideas to test, so I am not losing my confidence, that at least the solar system will be colonized sometime.
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#3737 by rfmwguy on 11 Jul, 2016 13:22
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I don't post my data here any longer, but I will address what is a misconception: As far as I know, EWs paper is not rejected but stalled. From here, I can only speculate and this is my best educated guess:Thanks. So that's the end of that then. Pretty downbeat ending to the whole enterprise.
Hard to accept...
but if so the Referees and Nasa must have had a reason for their decisions. I am quite sure by now that the concept is not working as we
expected it to work.
The Thing is: If an Experiment shows negative results (though scientifically constructive and in this sense positive) These results are never published nowadays.
So no News from Eagleworks means, that the EMDrive concept probably does not work, meaning that the thrust could not be measured in their improved Setup.
However, there are many more experimental ideas to test, so I am not losing my confidence, that at least the solar system will be colonized sometime.
Only one reviewer has not approved it.
The hang-up relates to the theory, not the test results.
This speculation is NOT based on anyone's info at EW, but I would consider it very trustworthy...and I didn't ask further questions.
The builders network is quite active off-forum and there are many private conversations we all choose not to make public for obvious reasons. So, drawing conclusions now is premature especially considering there is Summer recess for academia and reviewer(s) are likely out and about. So I wouldn't draw any conclusions, especially since many papers, especially at high levels of publishing, can take years to publish. While the wait is annoying, that's the way this thing is going. -
#3738 by Rodal on 11 Jul, 2016 14:30
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So, drawing conclusions now is premature especially considering there is Summer recess for academia and reviewer(s) are likely out and about.
No, to the contrary.
Those familiar with peer-reviewing for academic journals know that, generally speaking, Professors that are peer-reviewers, are generally not "out and about" during summer recess, for example having fun in a remote location, incommunicado , where they would not be available for reviewing articles in journals. All to the contrary, it is during summer recess that Professors that are peer-reviewers have more time to dedicate to review articles submitted to peer review journals. Actually, the Summer recess is when Professors have more time to actually do writing and research! They are generally busier reviewing articles for peer-review journals in the summer than the rest of the year. Summer is research, conferences, writing, haggling with publishers, etc. Summer is a time to catch up with research, papers, grants, etc., that may have been put off because of teaching during the school year. In the USA, in engineering and science, most professors work on research over the summer and hence receive money during the summer from research grants. (Of course this depends on the academic institution one is talking about, but this applies to what professors that are peer-reviewers do during the summer). Also, Ph.D. students and post-Ph.D. Researchers are not enjoying themselves in some island, they usually do not take the summer off. Their research is generally being paid by research grants, and hence they are expected to be working on their PhD and their research. Also Assistant Professors have to actively compete to get tenure, and the summer is a period in which to write papers (publish or perish !) and yes, peer-review other papers
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#3739 by rfmwguy on 11 Jul, 2016 15:55
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As with a potential for more test data you were not familiar with, there is good reason to believe that out of session travel and other commitments likely have lead to a delay. My point is there is no rejection to our collective knowledge and out of session delays lead to a further delay. Speculation by builders? Yes, but the belief is based on those with a good track record of calling it like it really is.So, drawing conclusions now is premature especially considering there is Summer recess for academia and reviewer(s) are likely out and about.
No, to the contrary.
Those familiar with peer-reviewing for academic journals know that, generally speaking, Professors that are peer-reviewers, are generally not "out and about" during summer recess, for example having fun in a remote location, incommunicado , where they would not be available for reviewing articles in journals. All to the contrary, it is during summer recess that Professors that are peer-reviewers have more time to dedicate to review articles submitted to peer review journals. Actually, the Summer recess is when Professors have more time to actually do writing and research! They are generally busier reviewing articles for peer-review journals in the summer than the rest of the year. Summer is research, conferences, writing, haggling with publishers, etc. Summer is a time to catch up with research, papers, grants, etc., that may have been put off because of teaching during the school year. In the USA, in engineering and science, most professors work on research over the summer and hence receive money during the summer from research grants. (Of course this depends on the academic institution one is talking about, but this applies to what professors that are peer-reviewers do during the summer). Also, Ph.D. students and post-Ph.D. Researchers are not enjoying themselves in some island, they usually do not take the summer off. Their research is generally being paid by research grants, and hence they are expected to be working on their PhD and their research. Also Assistant Professors have to actively compete to get tenure, and the summer is a period in which to write papers (publish or perish !) and yes, peer-review other papers
I'm using very heavy weight oil. I can switch to a lighter weight or change out the paddle for something smaller. The original paddle was 3 inches. This one is 6 inches. Perhaps a 4.5 inch paddle would work better. Very easy to switch it out.
