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#440
by
simplex1
on 07 Sep, 2016 23:58
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This is what an experimenter said after he had changed the orientation of the truncated cone:
"
I flipped the cone and I had the thrust pointing in the opposite direction. Unfortunately this thrust is around 7 times smaller." (Source:
http://www.masinaelectrica.com/tag/emdrive-frustrum-size)
The thrust should be the same.
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#441
by
RotoSequence
on 08 Sep, 2016 00:02
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The thrust should be the same.
This is only true if there are
no thermal effects, which is obviously not the case.
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#442
by
Bob Woods
on 08 Sep, 2016 00:09
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This is what an experimenter said after he had changed the orientation of the truncated cone:
"I flipped the cone and I had the thrust pointing in the opposite direction. Unfortunately this thrust is around 7 times smaller." (Source: http://www.masinaelectrica.com/tag/emdrive-frustrum-size)
The thrust should be the same.
I suggest you go back to earlier threads and start reading and you will find vast amounts of discussion on this and other items. Around March 2015 would be a good start.
But there is no thermal lift in a vacuum.
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#443
by
jay343
on 08 Sep, 2016 00:50
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Considering that the frustum is asymmetrical and that outer surface heating is not uniform, it's hard to estimate the net effect of heated air flowing around the device under test. But what if you eliminate it? Suppose you enclose the frustum in a symmetrical styrofoam jacket. Maybe that would eliminate any aerodynamic effects of heated air flowing around the frustum...
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#444
by
oyzw
on 08 Sep, 2016 01:04
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
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#445
by
Tellmeagain
on 08 Sep, 2016 01:58
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
Worse. Now you have both air jet effect as well as hot air balloon effect.
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#446
by
masterharper1082
on 08 Sep, 2016 02:27
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
Worse. Now you have both air jet effect as well as hot air balloon effect.
No, not worse. Air jet is a transient effect. There's only so much mass in the frustum to jet. Unless you have hooked up an air compressor to it.
Buoyancy force is parallel to gravity, and perpendicular to thrust from torsional pendulum experiments, which have the best thrust measurement capability.
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#447
by
masterharper1082
on 08 Sep, 2016 02:35
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Considering that the frustum is asymmetrical and that outer surface heating is not uniform, it's hard to estimate the net effect of heated air flowing around the device under test. But what if you eliminate it? Suppose you enclose the frustum in a symmetrical styrofoam jacket. Maybe that would eliminate any aerodynamic effects of heated air flowing around the frustum...
As the frustum is powered, it dumps resistive heat into the copper. Its temperature will rise much more with an insulating blanket - could cause a problem with material compatibility, and throw the unit even further out of tune unless using automatic retuning (mechanical or frequency-based).
Why not apply a blanket electrical heater on the inside of the frustum to characterize the natural convection force?
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#448
by
meberbs
on 08 Sep, 2016 03:40
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
Worse. Now you have both air jet effect as well as hot air balloon effect.
No, not worse. Air jet is a transient effect. There's only so much mass in the frustum to jet. Unless you have hooked up an air compressor to it.
Buoyancy force is perpendicular to gravity.
Most designs seal the inside pretty well, so the air jets should be small and possibly continuous for the entire time the power is on in many cases. At the force scale we are discussing these small jets could be quite significant.
Buoyancy is purely vertical as a force, but there are multiple ways depending on the experimental setup that it could be translated to a horizontal deflection, not to mention that some experiments have used vertical orientation.
Most emDrive experimental data I have looked at has had clear non-signal noise factors comparable to the "signal." Also I have noticed a trend that the more sensitive an experiment, and the lower the noise floor, the smaller the apparent signal. This is an indication to me that most experiments likely have multiple layers of error sources, and it is not clear any apparent signal is real.
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#449
by
FattyLumpkin
on 08 Sep, 2016 04:28
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The balloon effect could be mitigated entirely by filling (actually pumping out) the frustum via a Schrader valve to a pressure that is below ambient and is calculated not to exceed ambient when heated to maximum by the RF + I'd charge the frustum with nitrogen. This would be a very simple and inexpensive step in building a frustum. This has been mentioned several times before....any disagreements? Please? I've made the calculations and a 1/16" frustum should not collapse with the relatively small amount that the internal pressure is to be reduced.
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#450
by
TheTraveller
on 08 Sep, 2016 04:45
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Balloon effect has no effect on the resonant cavity, because cavity can leak air
How is your build going?
BTW I have had feedback that Prof Yang has not retired, is still working and that her positive results were verified at another Chinese facility.
Roger has stated he is doing cryo work with a UK aerospace company. Others tell me that there are more companies working on cryo EmDrive drives, so why not the Chinese?
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#451
by
TheTraveller
on 08 Sep, 2016 04:53
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NASA tests: "For the EMdrive, the device that was tested here, thrust was consistently observed on the device to be between 30-and-50 microNewtons, giving us that 1.2 N/MW figure. But the limits of the measuring device’s threshold was just 10-to-15 microNewtons! In other words, these results may be consistent and interesting, but this isn’t as robust as anyone wants it to be." Source: http://www.forbes.com/sites/startswithabang/2016/09/02/nasas-impossible-space-engine-the-emdrive-passes-peer-review/#1be7fbba692c
The thrust obtain by NASA is consistent with the thermal balloon lift I have calculated in my previous post (38.33 micro N).
It is true, some people claim they debunked the hot air balloon theory but the thrust obtained by them is much higher than the one observed by NASA so likely they made some mistakes.
Would suggest you ignore that data, as from what I'm told it is not even close to the paper's results as the thrust is reported to be much higher and uncertainty is much lower.
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#452
by
FattyLumpkin
on 08 Sep, 2016 04:58
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Traveller, What data is it that you suggest we ignore?
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#453
by
TheTraveller
on 08 Sep, 2016 05:07
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Traveller, What data is it that you suggest we ignore?
Ignore the thrust was 30-50uN and the min force recordable was 10 to 15uN. From what I'm told that is not correct and that the paper's thrust was much higher and the thrust uncertainty was much lower.
We know from other EW papers that thrust can be measured at the 1uN level. Question is the uncertainty.
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#454
by
FattyLumpkin
on 08 Sep, 2016 05:17
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Got it, what was leaked was confusing: EWL got much better results in there last campaign (especially in TE012) Can't imagine results getting worse, not to mention they were using PLL. Ciao!
BTW thanks for disclosing those frustum dimensions the other day. Can you tell us how you were feeding it, wave guide + maggie or dipole antenna in the frustum? or? FL
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#455
by
meberbs
on 08 Sep, 2016 05:25
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...
BTW I have had feedback that Prof Yang has not retired, is still working and that her positive results were verified at another Chinese facility.
Roger has stated he is doing cryo work with a UK aerospace company. Others tell me that there are more companies working on cryo EmDrive drives, so why not the Chinese?
Where is your info from on this?
This seems to contradict the fact that Yang retracted her original results, because she realized a flaw in the experimental setup, and a better setup did not produce significant force. (I forget if it was a 0, or just below experimental error, but those basically mean the same thing)
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#456
by
TheTraveller
on 08 Sep, 2016 05:27
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Got it, what was leaked was confusing: EWL got much better in there last campaign (especially in TE012) Can't imagine results getting worse, not to mention they were using PLL. Ciao!
BTW thanks for disclosing those frustum dimensions the other day. Can you tell us how you were feeding it, wave guide + maggie or dipole antenna in the frustum? or? FL
Single freq Rf via solid state Rf amp. Coax feed to 1/2 loop antenna on the side wall as is standard excitation method with accelerator cavities.
Bit smaller than this. More info in the document.
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#457
by
TheTraveller
on 08 Sep, 2016 05:33
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...
BTW I have had feedback that Prof Yang has not retired, is still working and that her positive results were verified at another Chinese facility.
Roger has stated he is doing cryo work with a UK aerospace company. Others tell me that there are more companies working on cryo EmDrive drives, so why not the Chinese?
Where is your info from on this?
This seems to contradict the fact that Yang retracted her original results, because she realized a flaw in the experimental setup, and a better setup did not produce significant force. (I forget if it was a 0, or just below experimental error, but those basically mean the same thing)
When did Prof Yang retract any of her peer reviewed papers?
BTW that last paper was using a single freq Rf source. As I and others have discovered, EW included, the freq needs to be adjusted to produce the lowest VSWR or it doesn't work. As far as I know Prof Yang did not use a S11 freq tracker and that may be why the data in her latest paper was low. Doing freq control via using a 2nd sense port is not effective for freq control.
That how to control the freq info is just a bit of EmDrive Engineering 101. Using a 2nd sense port doesn't work. Using tuning to lowest reflected power does work and there is no need of a 2nd hole in the frustum to support the sense port.
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#458
by
FattyLumpkin
on 08 Sep, 2016 05:44
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Damn! beautiful workmanship!!! Re the "big" build...I was scared off by the comment that was made that the frustum could be resonating well (say in TE013) but not produce thrust. I didn't want to put several thousands of dollars into a build that was going to fail. While I do understand confidentiality and NDAs, there are folks out here like myself who just what to contribute before we leave. Some one on Reddit asked about the size of Emdrives just yesterday...Imagine scaling your TE013 frustum up to the size of the inside diameter of a rocket fairing: +/- 4.5 meters for the base -large diameter...imagine the Q and the concomitant thrust that such a cavity would produce. I only wish to build a x 2 larger cavity that would resonate in the upper Megahertz range. But x 4 the surface area and x 8 the volume...how much would that increase Q?...am looking forward to the day when I can build big cavities and blast away! : ) K
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#459
by
FattyLumpkin
on 08 Sep, 2016 05:56
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Traveller what about antenna like this?