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#1160
by
rfmwguy
on 03 Jan, 2016 11:57
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Well...a cavity filled with nitrogen rather than hydrogen might be a better idea 
Yes, but I was thinking along the lines to choose the smallest atom to fill the cavity contents. Which is why I suggested Hydrogen. But any gas and pressures used. Would be an interesting additional test using the same EM Drive testbed.
Don
Good points. I've had arcing in some of my earlier static tests...for a second there I was imagining lakehurst, nj
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#1161
by
TheTraveller
on 03 Jan, 2016 12:10
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Well...a cavity filled with nitrogen rather than hydrogen might be a better idea
Yes, but I was thinking along the lines to choose the smallest atom to fill the cavity contents. Which is why I suggested Hydrogen. But any gas and pressures used. Would be an interesting additional test using the same EM Drive testbed.
Don
Good points. I've had arcing in some of my earlier static tests...for a second there I was imagining lakehurst, nj
My spherical end plate frustum will be sealed, with a digital pressure gauge and port. Plan to do tests at 1 Torr atmo, 1 Torr N2, normal atmo & normal atmo N2. Can pump down and fill with most gases. Really not interested in using H2. Have experience with it and the leak rate.
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#1162
by
rfmwguy
on 03 Jan, 2016 12:19
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Well...a cavity filled with nitrogen rather than hydrogen might be a better idea
Yes, but I was thinking along the lines to choose the smallest atom to fill the cavity contents. Which is why I suggested Hydrogen. But any gas and pressures used. Would be an interesting additional test using the same EM Drive testbed.
Don
Good points. I've had arcing in some of my earlier static tests...for a second there I was imagining lakehurst, nj
I'll venture a guess that ew allows the vacuum to ingress and egress. Don't think their frustum walls can support vacuum to air differential, but not sure. Tell you one thing, mags are used in CVD systems where a plasma is created. I'd want to understand exactly what might happen with various gases first before I flipped the switch.
Of course ejection of those gases would morph it from an emdrive to a plasma thruster. Lots of testing possibilities is what I like about the project...its new territory.
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#1163
by
TheUberOverLord
on 03 Jan, 2016 12:22
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Well...a cavity filled with nitrogen rather than hydrogen might be a better idea
Yes, but I was thinking along the lines to choose the smallest atom to fill the cavity contents. Which is why I suggested Hydrogen. But any gas and pressures used. Would be an interesting additional test using the same EM Drive testbed.
Don
Good points. I've had arcing in some of my earlier static tests...for a second there I was imagining lakehurst, nj
My spherical end plate frustum will be sealed, with a digital pressure gauge and port. Plan to do tests at 1 Torr atmo, 1 Torr N2, normal atmo & normal atmo N2. Can pump down and fill with most gases. Really not interested in using H2. Have experience with it and the leak rate.
Well any different gases and different pressures would be welcomed tests. If a force is involved in creating thrust minus thermal trust. Thrust results might increase or decrease substantially, by many magnitudes. Dependant of cavity contents and pressures.
I think it's safe to say that changes in cavity contents, temperature and pressures would and does cause changes in resonance for the same EM Drive.
Don
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#1164
by
Mulletron
on 03 Jan, 2016 12:30
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Would it not be interesting to see the cavity pressurized at normal atmospheric levels and then times x atmospheric levels. Using our typical atmosphere components as well as trying other gases in both normal and vacuum testbed environments? Down the road, but soon?
After all. Since the contents of the cavity may have already shown decreases and increases in measured thrust output. Might it not be possible that the contents of the cavity could increase or decrease the magnitude of thrust many times over? Depending on what the contents of the cavity contains. In both a vacuum and at normal atmospheric pressures.
Since it might be possible that depending on the contents of the cavity. More thrust in a vacuum might be created than at normal atmospheric pressures.
If particles in the cavity are somehow involved in this thrust process. Would it not be worthwhile to be thinking about this for future tests?
Note: One thing that always perplexed me about the vacuum tests so far. Was that there was no test data on if the cavity had normal atmospheric contents and pressure in the vacuum. Would the thrust results have remained as low as they were?
Would love to see a test with a cavity using normal atmospheric pressure but the cavity contents filled with Hydrogen and then compare the results using the same EM Drive setup with the cavity contents replaced with normal atmospheric contents at the same atmospheric pressure.
Instead of water or air, think cavity contents. If thrust has anything to do with cavity contents, pressures and/or the resonance of the particles in the cavity contents:
Water: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol2.html#c2
Air: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol.html
Don
As to your note, I remember Star-Drive mention the Eagleworks frustum is allowed to vent atmo while in the vacuum chamber.
I agree with you on swapping out gases and dielectrics based on their properties. For instance, Oxygen is paramagnetic. Nitrogen is diamagnetic. If a pure oxygen atmosphere produced different results (and not blowing up) than a pure nitrogen atmosphere, that would be a significant lead.
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#1165
by
Mulletron
on 03 Jan, 2016 12:34
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...
Lately I've been focused on just the type 3 cavity and really thinking hard about all of the properties of the air and why it seems important to thrust (Shawyer did away with the dielectric). It must be the related to the collective natural motion of the molecules in the cavity, but perturbed by some still unknown method. No doubt, that if the reports of thrust are not due to some artifact, there must be an explanation; maybe even one of the above. I don't know what could be behind the thrust with any certainty. What I'm proposing with the sound is (in my view) agnostic to the underlying thrust mechanism. It is simply adding energy to the system. If an anisotropy is present, I believe this may be a way to expose it by bringing forces up to a measurable level.
Has it ever been discussed, that we might have accidently stumbled over some kind of a "Maxwell Daemon"?: http://physicsworld.com/cws/article/news/2010/nov/19/information-converted-to-energy
It has been discussed in earlier threads.
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1334265#msg1334265and other places.
A surefire way to find any post from earlier threads is to use this type of search in Google:
maxwell's demon emdrive site:nasaspaceflight.com
https://www.google.com/search?q=maxwell%27s+demon+emdrive+site%3Anasaspaceflight.com&ie=utf-8&oe=utf-8
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#1166
by
TheUberOverLord
on 03 Jan, 2016 12:38
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Would it not be interesting to see the cavity pressurized at normal atmospheric levels and then times x atmospheric levels. Using our typical atmosphere components as well as trying other gases in both normal and vacuum testbed environments? Down the road, but soon?
After all. Since the contents of the cavity may have already shown decreases and increases in measured thrust output. Might it not be possible that the contents of the cavity could increase or decrease the magnitude of thrust many times over? Depending on what the contents of the cavity contains. In both a vacuum and at normal atmospheric pressures.
Since it might be possible that depending on the contents of the cavity. More thrust in a vacuum might be created than at normal atmospheric pressures.
If particles in the cavity are somehow involved in this thrust process. Would it not be worthwhile to be thinking about this for future tests?
Note: One thing that always perplexed me about the vacuum tests so far. Was that there was no test data on if the cavity had normal atmospheric contents and pressure in the vacuum. Would the thrust results have remained as low as they were?
Would love to see a test with a cavity using normal atmospheric pressure but the cavity contents filled with Hydrogen and then compare the results using the same EM Drive setup with the cavity contents replaced with normal atmospheric contents at the same atmospheric pressure.
Instead of water or air, think cavity contents. If thrust has anything to do with cavity contents, pressures and/or the resonance of the particles in the cavity contents:
Water: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol2.html#c2
Air: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol.html
Don
As to your note, I remember Star-Drive mention the Eagleworks frustum is allowed to vent atmo while in the vacuum chamber.
But no test data was produced using their EM Drive comparing the cavity using normal atmospheric contents and at normal atmospheric pressure in their vacuum chamber vs. the cavity being at vacuum pressure. To date, I don't think a test like that in a vacuum has ever been tried, with a EM Drive?
Don
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#1167
by
Mulletron
on 03 Jan, 2016 12:45
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I do not recall any test of a pressurized EmDrive placed inside a vacuum. It has been discussed back in thread 2 I believe, but it is difficult.
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#1168
by
TheUberOverLord
on 03 Jan, 2016 12:55
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I do not recall any test of a pressurized EmDrive placed inside a vacuum. It has been discussed back in thread 2 I believe, but it is difficult.
Not sure why it would be difficult for those like EW to do. Sure it would be difficult for a typical DIY to accomplish in a vacuum, but not necessarily at normal atmospheric pressures. Done safely of course with different gases and pressures.
Maybe I'm wrong, but at face value looking at some of RS past EM Drive testbeds. They looked like they could have pulled off a test like this in a vacuum chamber, with some minor modifications?
Done well, one could then start experimenting with many different pressures and gases rather quickly. From test to test. With or without a vacuum chamber.
It might even help to compare any thrust differences currently speculated to be caused by thermal artifacts by using different gases and pressures in EM Drive cavities?
Just saying that tests like this might help better determine if any particle interactions in the cavity contribute to thrust levels from EM Drives.
Don
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#1169
by
Mulletron
on 03 Jan, 2016 12:59
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I would imagine a copper frustum (if you could seal it properly) would blow up like a balloon inside a vacuum chamber.
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#1170
by
TheUberOverLord
on 03 Jan, 2016 13:01
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I would imagine a copper frustum (if you could seal it properly) would blow up like a balloon inside a vacuum chamber.
Yes. But RS seemed to show some frustums ("In pictures') of those past testbeds. That at face value, seem like they could survive in a vacuum chamber. Maybe I am giving those pictures too much credit?
That said, I'm sure that EW could have pulled off a test like this and am somewhat surprised it's not been a high priority for vacuum testing of EM Drives. At least at this stage of EM Drive testing.
Don
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#1171
by
Mulletron
on 03 Jan, 2016 13:10
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#1172
by
TheUberOverLord
on 03 Jan, 2016 13:11
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(...)
I'll venture a guess that ew allows the vacuum to ingress and egress. Don't think their frustum walls can support vacuum to air differential, but not sure. ....
I believe Paul March mentioned in an earlier post, that their frust did leak and vacuum equalized inside and out. Tread 5? somewhere I think.
That's my point.
Since particle involvement in a frustum cavity of a EM Drive has not yet been ruled out as a contributor to thrust. It seems to me to be a missing standard step at this stage of EM Drive testing in a vacuum to not have normal atmospheric content and pressures in the frustum cavity as a part of a vacuum test.
Especially more so at this stage of EM Drive testing where it would seem that when the frustum cavity does not have normal atmospheric content and pressures in a vacuum, that much less thrust is the result.
Don
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#1173
by
OnlyMe
on 03 Jan, 2016 13:17
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I would imagine a copper frustum (if you could seal it properly) would blow up like a balloon inside a vacuum chamber.
Yes. But RS seemed to show some frustums ("In pictures') of those past testbeds. That at face value, seem like they could survive in a vacuum chamber. Maybe I am giving those pictures too much credit?
That said, I'm sure that EW could have pulled off a test like this and am somewhat surprised it's not been a high priority for vacuum testing of EM Drives. At least at this stage of EM Drive testing.
Don
Since Eagleworks has been the only significant vacuum capable
tester, I think just getting any results in vacuum, has been/is the goal...
Still waiting on peer review for anything more from them.
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#1174
by
SeeShells
on 03 Jan, 2016 13:24
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Well...here's my first shot at computing an endplate 'energy' picture from the meep data.
I hesitate to call this the thermal signature because I'm guessing at the equation.
This picture was generated with the following algorithm:
(where each frame element is the <x,y,z> H field 3 vector)
for each frame 1..112
for each row
for each col
sum[row][col] += abs( VCos_Angle(data[frame][row][col] , z) ) * vlength(data[frame][row][col]);
This sum is then output as the height of a cylinder and colored as in the picture. Elements whose resulting value < 1e-6 are ignored. The "MAX" shown is automatically computed as the highest value of the sum array. The MIN is 0 to 3 decimal points as shown. Values are in 'meep units'.
This was my best guess at a reasonable way to compute this. If a different algorithm is desired, let me know.
This meep model file is from aero modeling SeeShells' device. It is the same data as used to generate the H field animations I've been posting.
It looks pretty darn close to both TM12 and TE12!
Doing this for the small end is pretty trivial. Doing it for the conical section is a son-of-a-gun, but I'm working on it 
What model are you running?
This meep model file is from aero modeling SeeShells' device. It is the same data as used to generate the H field animations I've been posting.
(I thought that Shell and aero were expecting TE01 instead of TE12)(completely different mode !!! )
Actually the mode shown by the Meep model does not look like any of these modes, really...
That's the reason why I had suggested making this verification comparison
All Meep runs need verification to compare with reality The problem is not with Meep, the issue is with the particular models
pardon the word "garbage" which is not meant to be offensive, it is enshrined in computer science:
https://en.wikipedia.org/wiki/Garbage_in,_garbage_out
I'm a programmer, I totally understand GIGO
There are a LOT of steps in this chain, and some guesswork on my part, so each of those requires scrutiny.
FIRST and foremost in my mind: is the algorithm (posted above) correct?
Following right behind that is: did I implement it correctly? i.e. does this output accurately reflect what the meep model generates? If I have that right then we work back up the chain to the meep model itself.
One note: This looks to me to match the data I see in the animations. Of course part of the same tool chain is used (conversion of the CSV files output from the h5totxt to the POV-Ray include files using C++ code I wrote), so the errors could be common to that. I have manually spot-checked data values and found them to have been copied correctly from input to output, but peer review is a 'very good thing'.
I was never comfortable with the fact that the above graphic didn't show the square waveguides. And I was right to question that - this is the wrong Z slice! ZERO is the middle of the simulation grid (the way I used h5totxt) and therefore the 'big end' is -112 and the 'small end' is 58. Verified by running this against -113 (which shows basically nothing as all the data is <1e-6) and 59 also shows nothing. The above graphic was 34 so almost at the small end, but not quite..
Attached is the big end and small end graphics with the correct Z slices.
I believe you can see the mode in this animation of 10 slices for on cycle and how it relates to Maxheadroom's graphic in thermal. I paused it at the peak of of the energy in the mode to see. It matches the CSV data quite closely. How close it matches the real world using the thermal camera is to be seen.
Shell
Added: What would be interesting is to drop the small end CSV data sample down into the mode and see it it also agrees and the difference in energy levels.
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#1175
by
OnlyMe
on 03 Jan, 2016 13:25
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(...)
That's my point.
Since particle involvement in a frustum cavity of a EM Drive has not yet been ruled out as a contributor to thrust. It seems to me to be a missing standard step at this stage of EM Drive testing in a vacuum to not have normal atmospheric content and pressures in the frustum cavity as a part of a vacuum test.
Especially more so at this stage of EM Drive testing where it would seem that when the frustum cavity does not have normal atmospheric content and pressures in a vacuum, that much less thrust is the result.
Don
That may be a long game goal, but I don't believe anyone including Eagleworks, is at that stage yet. Got to demonstrate thrust clearly out of the noise and thermal effects before, any sort of tweaking becomes practical. You need a documented and repeatable baseline thrust, to work with.
The frustum once shown to function in atmosphere, very well may need to be gas filled, to function in vacuum. But you need a working EMDrive to begin with....
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#1176
by
TheUberOverLord
on 03 Jan, 2016 13:31
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I would imagine a copper frustum (if you could seal it properly) would blow up like a balloon inside a vacuum chamber.
Yes. But RS seemed to show some frustums ("In pictures') of those past testbeds. That at face value, seem like they could survive in a vacuum chamber. Maybe I am giving those pictures too much credit?
That said, I'm sure that EW could have pulled off a test like this and am somewhat surprised it's not been a high priority for vacuum testing of EM Drives. At least at this stage of EM Drive testing.
Don
Since Eagleworks has been the only significant vacuum capable tester, I think just getting any results in vacuum, has been/is the goal...
Still waiting on peer review for anything more from them.
(...)
That's my point.
Since particle involvement in a frustum cavity of a EM Drive has not yet been ruled out as a contributor to thrust. It seems to me to be a missing standard step at this stage of EM Drive testing in a vacuum to not have normal atmospheric content and pressures in the frustum cavity as a part of a vacuum test.
Especially more so at this stage of EM Drive testing where it would seem that when the frustum cavity does not have normal atmospheric content and pressures in a vacuum, that much less thrust is the result.
Don
That may be a long game goal, but I don't believe anyone including Eagleworks, is at that stage yet. Got to demonstrate thrust clearly out of the noise and thermal effects before, any sort of tweaking becomes practical. You need a documented and repeatable baseline thrust, to work with.
The frustum once shown to function in atmosphere, very well may need to be gas filled, to function in vacuum. But you need a working EMDrive to begin with....
Not trying to be sarcastic. But I think even most DIY EM Drive builders, have had better test plans with even more limited budgets. If test A fails, what should test B and so on?
Looks like EW and others doing EM Drive vacuum testing need better test plans before doing test A and failing and not having any test B.
What's the point in doing the vacuum test otherwise. To say "No particles in the cavity means little to no thrust in a vacuum. But we can't say what would/could happen if their were particles in the cavity in a vacuum".
So did the EM Drive vacuum test fail due to no particles in the cavity? Or did the test fail because one can't create the same thermal artifacts one can in a normal atmosphere?
Don
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#1177
by
OnlyMe
on 03 Jan, 2016 13:34
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(...)
Not trying to be sarcastic. But I think even most DIY EM Drive builders, have had better test plans with even more limited budgets. If test A fails, what should test B and so on be?
Looks like EW and others doing EM drive vacuum testing need better test plans before doing test A and failing and not having any test B.
What's the point in doing the vacuum test otherwise. To say "No particles in the cavity means no thrust in a vacuum. But we can't say what would/could happen if their were particles in the cavity in a vacuum".
So did the EM Drive vacuum test fail due to no particles in the cavity? Or did the test fail because one can't create the same thermal artifacts one can in a normal atmosphere?
Don
Everyone has been starting from scratch design wise... And if you think back Eagleworks began testing several even unrelated designs. Even adding a dielectric or an empty can is a different design... no one started with a blueprint that had any guarantee of success from either of the earlier testers, Shawyer or Yang... And each experimenter has to be evaluated independently, at present.., at least until there is some real evidence or confirmation that they have been testing the same design. Small changes in dimensions or microwave supply make a big difference it seems.
Edit: BTW everyone including EW has been working on a limited budget so far!
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#1178
by
TheUberOverLord
on 03 Jan, 2016 13:47
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(...)
Not trying to be sarcastic. But I think even most DIY EM Drive builders, have had better test plans with even more limited budgets. If test A fails, what should test B and so on be?
Looks like EW and others doing EM drive vacuum testing need better test plans before doing test A and failing and not having any test B.
What's the point in doing the vacuum test otherwise. To say "No particles in the cavity means no thrust in a vacuum. But we can't say what would/could happen if their were particles in the cavity in a vacuum".
So did the EM Drive vacuum test fail due to no particles in the cavity? Or did the test fail because one can't create the same thermal artifacts one can in a normal atmosphere?
Don
Everyone has been starting from scratch design wise... And if you think back Eagleworks began testing several even unrelated designs. Even adding a dielectric or an empty can is a different design... no one started with a blueprint that had any guarantee of success from either of the earlier testers, Shawyer or Yang... And each experimenter has to be evaluated independently, at present.., at least until there is some real evidence or confirmation that they have been testing the same design. Small changes in dimensions or microwave supply make a big difference it seems.
Edit: BTW everyone including EW has been working on a limited budget so far!
Well understood. But nobody in this test case by EW. Knows what that same EM Drive testbed would/could have done outside of a vacuum. So if one wants to do only a vacuum test of an EM Drive. Should one of the steps ("At this stage of EM Drive testing") be at least filling the frustum cavity with normal atmospheric pressure and contents?
I mean, without using the same EM Drive testbed outside of a vacuum chamber and also dropping that step while only doing a vacuum test of a EM Drive seems to have created a "Black Hole" of missing data. Making it extremely complicated to determine what the end results mean.
Does anyone disagree that replacing the normal atmospheric particles in a EM Drive cavity at normal atmospheric pressure with a vacuum instead, changes the EM Drive cavities resonance?
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1469066#msg1469066Note: Even the same cavities harmonics would change in a vacuum. Not to mention that light travels faster in a vacuum than it does in a normal atmosphere. Think of all these variables being changed with the exact same EM Drive.
Don
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#1179
by
OnlyMe
on 03 Jan, 2016 14:14
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The black hole in DIY data is more an issue of being able to record credible data, before time or money run out.
For EW, it is almost certain that they had a great deal more that has not been shared, than what has been. Even in peer reviewed and published work, you will seldom see all of the data from everything that was tried.
We all want to see and know everything about every step.., including how long Shell sits impatiently twiddling her thumbs, while waiting for some delivery she has no control over.
The truth is this is not interactive reality TV. What is discussed here does have some impact on both the DIY builds and testing and likely even EW, but we will never see everything that happen behind the scenes.
On the issue of vacuum and resonance, I am sure that it does and it has been mentioned in past posts, even to the point that in EWs early vacuum tests it was not possible to fine tune the resonance while in vacuum. I don't that it is true, but I would be surprised if that were not one of the things EW has, at least attempted to resolve.
The way a frustum is being constructed in most of these early attempts, it would be impractical to test where the air pressure was not the same inside and out.., without as mentioned by someone else the thing blowing up like a balloon. Shell did mention she could gas fill her build with a gas that would help eliminate arcing. I assume that would still be to the same pressure inside and out.
ADD: The speed of light in vacuum vs air over the distances inside a frustum..? I don't think they can be thought of as significant. Someone mentioned way back that even red shifting would be insignificant, where the distances and accelerations involved are comcerned.
