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#2340 by Mulletron on 20 Oct, 2014 14:52
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Been playing around with CAD. See yellow circle in dwg. The vector images in the PDF were squashed. This all hinges on IF the inside of the cavity is 6.25" at the small end. You can 3d orbit to see my construction from left to right. Hope this helps. The website won't let me upload a .dwg. The numbers are in inches and approximate.
The link to it is here:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing
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#2341 by Mulletron on 20 Oct, 2014 14:59
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Here is the PDF mentioned above.
http://www.emdrive.com/iac2014presentation.pdf
Is there a paper with more details to be published ?
"4 independent organisations, in 3 different countries" : what organisations ? with what kind of balance ? Someone present at the conference to take notes and give some context ?
...
Shawyer is now claiming with no no dielectric 952 mN/KW, compared to Cannae with dielectric 1.7 mN/KW (600 times less)
Sheeez
Where is it said the Superconducting Cannae isn't using dielectric? -
#2342 by Mulletron on 20 Oct, 2014 15:19
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Here is the PDF mentioned above.
http://www.emdrive.com/iac2014presentation.pdf
Is there a paper with more details to be published ?
"4 independent organisations, in 3 different countries" : what organisations ? with what kind of balance ? Someone present at the conference to take notes and give some context ?
...
Shawyer is now claiming with no no dielectric 952 mN/KW, compared to Cannae with dielectric 1.7 mN/KW (600 times less)
Sheeez
Where is it said the Superconducting Cannae isn't using dielectric?
Is the drawing shown next to puny Cannae 1 mN/KW symmetric and with dielectric?
Is the drawing shown next to mighty superconducting Cannae 1000 mN/KW unsymmetric and with no dielectric?
The language of engineers and scientists is drawings, spreadsheets, plots, numbers and formulas instead of words.
Those drawings aren't one for one with the table to the right. sheesh. -
#2343 by Mulletron on 20 Oct, 2014 15:23
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Well, for that we have wembley's information regarding no dielectric. So thereHere is the PDF mentioned above.
http://www.emdrive.com/iac2014presentation.pdf
Is there a paper with more details to be published ?
"4 independent organisations, in 3 different countries" : what organisations ? with what kind of balance ? Someone present at the conference to take notes and give some context ?
...
Shawyer is now claiming with no no dielectric 952 mN/KW, compared to Cannae with dielectric 1.7 mN/KW (600 times less)
Sheeez
Where is it said the Superconducting Cannae isn't using dielectric?
Is the drawing shown next to puny Cannae 1 mN/KW symmetric and with dielectric?
Is the drawing shown next to mighty superconducting Cannae 1000 mN/KW unsymmetric and with no dielectric?
The language of engineers and scientists is drawings, spreadsheets, plots, numbers and formulas instead of words.
Those drawings aren't one for one with the table to the right. sheesh.
PS: please take a look at my message on the AutoCAD drawing
I can't convert it to something else. It is a 3d drawing anyway. Find a free autocad viewer. The inside dimensions of the cavity are known to me, but not usable to me because of the lack of depth perception in the photo. The bottom diagonal line in the photo was mirrored from the top line instead of drawn manually, and it lined up close to the photo, so I got the center and the width of the small end pretty close to 6.25. That was the sanity check. -
#2344 by Mulletron on 20 Oct, 2014 15:31
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....
Well, sheeesh
I can't convert it to something else. It is a 3d drawing anyway. Find a free autocad viewer. The inside dimensions of the cavity are known to me, but not usable to me because of the lack of depth perception in the photo.
Can you at least post:
Large Diameter=?
Small Diameter=6.25 inches
Length=?
how much work is that instead of all that stuff about polyethylene having magic properties
How would you like it if I would post that I computed that polyethylene has magic thrusting capability with a Mathematica version 10.1 file that you cannot read?
The dims are in the pic, sheesh.......Hello McFly!!!!!!!! knock, knock, knock........
Edited for comedic effect. No disrespect meant, just busting ur balls a bit. Love you guys.
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#2345 by Rodal on 20 Oct, 2014 15:39
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Dimensions in metric units (based on http://forum.nasaspaceflight.com/index.php?topic=29276.msg1273869#msg1273869):
Brady et. al. truncated cone, frustum, dimensions
Length = 0.27635 m
Large Diameter = 0.30523 m
Small Diameter = 0.15875
EDIT: Let's wait until JohnFornaro provides his AutoCAD dimension assessment since the above dimensions are predicated on an assumed small diameter of 6.25 inches (is that known for sure or is it an arbitrary dimension?) and since it is better to have 3 assessments (this last one +aero+JohnFornaro) to calculate
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#2346 by Notsosureofit on 20 Oct, 2014 15:40
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http://scitation.aip.org/content/aip/magazine/physicstoday/news/10.1063/PT.5.7115?utm_medium=email&utm_source=Physics+Today&utm_campaign=4848808_Physics+Today%3a+The+week+in+Physics+13-17+October&dm_i=1Y69,2VXD4,E1MTSN,AG4QR,1
Just an odd analogy that just popped up. Note the motion to the right of the resonating "Hawking Black Hole" -
#2347 by Rodal on 20 Oct, 2014 15:42
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http://scitation.aip.org/content/aip/magazine/physicstoday/news/10.1063/PT.5.7115?utm_medium=email&utm_source=Physics+Today&utm_campaign=4848808_Physics+Today%3a+The+week+in+Physics+13-17+October&dm_i=1Y69,2VXD4,E1MTSN,AG4QR,1
Just an odd analogy that just popped up. Note the motion to the right of the resonating "Hawking Black Hole"
Outstanding !
Notice: <<continuing emission of Hawking phonons>>
phonons ==> hence heat ! -
#2348 by Mulletron on 20 Oct, 2014 15:52
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Ok, instead of Sheeshing around I will post the Mulletronized dimensions in a language that we can understand (and more noticeable than muted colors on a black background, sheesh
:
Brady et. al. truncated cone, frustum, dimensions
Length = 0.27635 m
Large Diameter = 0.30523 m
Small Diameter = 0.15875
compared to the dimensions now in McCulloch's chart:
Length = 0.345 m (25% longer)
Large Diameter = 0.28 (8% smaller)
Small Diameter = 0.17 0.15875 (7% larger)
I think someone needs to have a word with you. This disrespectful language about trash bags being made of PE is nonsense. Panty hose are made of Nylon. That doesn't make Nylon any less of a world changer. I spend an hour doing an autocad for the group and you want to pitch a fit. You didn't even click on the picture. Sheesh. -
#2349 by Rodal on 20 Oct, 2014 17:54
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1) Does Shawyer explain Conservation of Energy as due to unequal Doppler shift in the forward and aft directions ? (See below)Here is the PDF mentioned above.
http://www.emdrive.com/iac2014presentation.pdf
Is there a paper with more details to be published ?
"4 independent organisations, in 3 different countries" : what organisations ? with what kind of balance ? Someone present at the conference to take notes and give some context ?
2) New Shawyer Superconducting EM Drive (just like in his new patent) attached below.
3) Notice "piezoelectric compensation for Doppler shift"
4) Notice that fore and aft walls of new Shawyer EM Drive are curved. They are not longer flat bases of a truncated cone. Perhaps the reason for this is to be able to analyze the resonant modes with a closed-form solution, and thereby to have a better handle at what frequencies the resonant mode frequencies are expected.
5) Notice that there is no longer a cylindrical section to Shawyer's EM Drive that previously was actuated by a motor in order to change the active length of the cavity in order to mechanically control the frequencies at which resonance takes place.
6) Notice that the radial-direction "length" of EM Drive in this new design is now significantly shorter than the length of the circumferential-direction fore and aft surfaces.
EDIT: It is interesting that in Shawyer's superconducting EM Drive design he has considerably reduced the ratio of the radial length "L" of the cavity with respect to the "diameters of the bases".
Previous Shawyer's design and NASA Eagleworks frustum approximately L = BigDiameter and L > SmallDiameter
in Shawyer's new design L < BigDiameter and L < SmallDiameter
this now is closer to meeting the required acceleration for Unruh waves as one needs to meet:
(Diameter/(CavityLength) > 4
7) Notice Shawyer's new EM Drive cavity is made of superconducting yttrium-barium-copper-oxide next to low-thermal-expansion Invar nickel–iron alloy.
8) The picture (attached at the bottom) in the Single Stage to Orbit vehicle shows the old cylinder+truncated cone design of EM Shawyer drive rather than the new superconducting design.
9) This is all that I have been able to find on Cannae's superconducting device (notice it is ~ 3 years old):
http://web.archive.org/web/20121102082714/http://www.cannae.com/proof-of-concept/experimental-results
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#2350 by Rodal on 20 Oct, 2014 18:44
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Bob Ludwick sent me the following message that I post in its entirety (I added bolding for emphasis):
From: Robert Ludwick
Sent: Sunday, October 19, 2014 10:13 PM
To: Dr. J. Rodal
Subject: Microwave sources
Hello Dr. Rodal,
IslandPlaya, made this comment, perhaps facetiously:
"Indeed! We need microwave sources that are stable to <0.1 Hz and tunable."
Such sources are readily available from several sources. This one from
Keysight(formerly HP, then Agilent, now Keysight) is representative:
http://literature.cdn.keysight.com/litweb/pdf/5989-0698EN.pdf
It is tunable in 0.001 Hz steps and is as stable as the reference source if
driven externally. Off the shelf cesium reference sources are stable in the
e(-13) range, which means that 0.001 Hz steps in the sub-3 GHz range where all
the EmDrive testing has been done are actually meaningful. Using the internal
source it is stable to +/- 2.5 parts in 10^(-10)/day.
It sounds expensive, until you add up the wasted time and false starts that
can reasonably attributed to testing high Q devices ‘on the cheap’.
Whether or not the Mini-Circuits free running VCO driven by a variable power
supply was causing flaky experimental results, it would be nice to be able
(until Q’s approach Sawyer’s postulated 1e9, where phase noise much closer
than 1 Hz to the carrier becomes an issue) to take source stability off the
‘What’s going on here?’ table.
Bob Ludwick -
#2351 by aero on 20 Oct, 2014 18:56
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I mentioned cosine losses earlier. I wonder, would the RF waves in a small piece of the cavity parallel to the side wall of the cavity produce thrust in the axial direction like delta thrust = delta force * cos(cone half-angle)?
Question: Would the taper, or cone half angle result in cosine losses from the forces generated by the EM thruster? If so, what would be the relative magnitude of such cosine losses?
It is a little bit important because the experimentally measured thrust would necessarily include the cosine loss while our force models do not. But it should be an easy fix to the math models. -
#2352 by Rodal on 20 Oct, 2014 19:15
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I mentioned cosine losses earlier. I wonder, would the RF waves in a small piece of the cavity parallel to the side wall of the cavity produce thrust in the axial direction like delta thrust = delta force * cos(cone half-angle)?
Question: Would the taper, or cone half angle result in cosine losses from the forces generated by the EM thruster? If so, what would be the relative magnitude of such cosine losses?
It is a little bit important because the experimentally measured thrust would necessarily include the cosine loss while our force models do not. But it should be an easy fix to the math models.
I can't calculate a net thrust force for these devices based on classical mechanics so I can't comment on the contribution from the cone revolving surface vs. the contribution from the cone bases. I posed the question of what happens in the limit as the small base becomes infinitesimally small towards a point (in which case his formula goes to infinity) to Dr. McCulloch and he answered that he had to think about it. It seems to me that infinite (let alone finite) forces are precluded, and therefore that the revolving cone surface must have an important negative contribution to preclude the infinity that occurs with a pointy cone.
Shawyer points out that the main losses are due to "extraction of kinetic energy, which lower the loaded Q" he thus differentiates between a loaded Q and an unloaded Q, due to conservation of energy:
"The Q of any resonant circuit can be defined as the stored energy divided by the energy loss per cycle. Thus as soon as kinetic energy is extracted from the engine, the stored energy, and hence the Q, falls."
See: http://emdrive.com/firstgenapplications.html -
#2353 by aero on 20 Oct, 2014 19:40
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I mentioned cosine losses earlier. I wonder, would the RF waves in a small piece of the cavity parallel to the side wall of the cavity produce thrust in the axial direction like delta thrust = delta force * cos(cone half-angle)?
Question: Would the taper, or cone half angle result in cosine losses from the forces generated by the EM thruster? If so, what would be the relative magnitude of such cosine losses?
It is a little bit important because the experimentally measured thrust would necessarily include the cosine loss while our force models do not. But it should be an easy fix to the math models.
Shawyer points out that the main losses are due to "extraction of kinetic energy, which lower the loaded Q" he thus differentiates between a loaded Q and an unloaded Q, due to conservation of energy:
"The Q of any resonant circuit can be defined as the stored energy divided by the energy loss per cycle. Thus as soon as kinetic energy is extracted from the engine, the stored energy, and hence the Q, falls."
See: http://emdrive.com/firstgenapplications.html
You quoted me but didn't address my question. Sure there are other losses but cosine loss is the reduction of the thrust component in the axial direction, (direction of acceleration) due to the rocket engine being pointed at an angle to the axial direction. In this case of course the whole EM thruster is pointed in the axial direction but the nozzle with flat ends is not shaped to redirect the off axis forces in the axial direction. Maybe a drawing will help.
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#2354 by Rodal on 20 Oct, 2014 19:44
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I mentioned cosine losses earlier. I wonder, would the RF waves in a small piece of the cavity parallel to the side wall of the cavity produce thrust in the axial direction like delta thrust = delta force * cos(cone half-angle)?
Question: Would the taper, or cone half angle result in cosine losses from the forces generated by the EM thruster? If so, what would be the relative magnitude of such cosine losses?
It is a little bit important because the experimentally measured thrust would necessarily include the cosine loss while our force models do not. But it should be an easy fix to the math models.
Shawyer points out that the main losses are due to "extraction of kinetic energy, which lower the loaded Q" he thus differentiates between a loaded Q and an unloaded Q, due to conservation of energy:
"The Q of any resonant circuit can be defined as the stored energy divided by the energy loss per cycle. Thus as soon as kinetic energy is extracted from the engine, the stored energy, and hence the Q, falls."
See: http://emdrive.com/firstgenapplications.html
You quoted me but didn't address my question. Sure there are other losses but cosine loss is the reduction of the thrust component in the axial direction, (direction of acceleration) due to the rocket engine being pointed at an angle to the axial direction. In this case of course the whole EM thruster is pointed in the axial direction but the nozzle with flat ends is not shaped to redirect the off axis forces in the axial direction. Maybe a drawing will help.
I build my posts my frequent adding and re-editing. Yes, I added this [at 7:29PM before your 7:40PM message] to address your question:
"I can't calculate a net thrust force for these devices based on classical mechanics so I can't comment on the contribution from the cone revolving surface vs. the contribution from the cone bases. I posed the question of what happens in the limit as the small base becomes infinitesimally small towards a point (in which case his formula goes to infinity) to Dr. McCulloch and he answered that he had to think about it. It seems to me that infinite (let alone finite) forces are precluded, and therefore that the revolving cone surface must have an important negative contribution to preclude the infinity that occurs with a pointy cone."
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#2355 by aero on 20 Oct, 2014 19:44
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Shawyer did answer my email in which I ask him for the dimensions of the resonance cavity.
His answer was,
"The small end diameters are set just above the cut-off diameter corresponding to the mode and frequency of the design."
Maybe that will help someone here. Not me. -
#2356 by aero on 20 Oct, 2014 19:49
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@Rodal
I think we are talking past each other. Look at my drawing - if that doesn't communicate let me know what it does say to you. -
#2357 by Rodal on 20 Oct, 2014 19:53
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@Rodal
As a direct answer to the statement "cosine loss is the reduction of the thrust component in the axial direction, (direction of acceleration) due to the rocket engine being pointed at an angle to the axial direction", I cannot understand these EM Drives as a thrusting rocket producing vectors of force, therefore I cannot use the analogy to validate a cosine loss.
I think we are talking past each other. Look at my drawing - if that doesn't communicate let me know what it does say to you.
From classical (Maxwell's equations) electromagnetic microwave cavity theory I am closer to Frobnicat regarding the electromagnetic tensor causing presure on the cavity surfaces that cancel out (no net thrust to accelerate the center of mass of the EM Drive). -
#2358 by Rodal on 20 Oct, 2014 19:59
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@Rodal
As a direct answer to the statement "cosine loss is the reduction of the thrust component in the axial direction, (direction of acceleration) due to the rocket engine being pointed at an angle to the axial direction", I cannot understand these EM Drives as a thrusting rocket, therefore I cannot use the analogy to validate a cosine loss.
I think we are talking past each other. Look at my drawing - if that doesn't communicate let me know what it does say to you.
From classical (Maxwell's equations) electromagnetic microwave cavity theory I am closer to Frobnicat regarding electromagnetic tensor causing presure on the cavity surfaces that cancel out (no net thrust to accelerate the center of mass of the EM Drive).
Perhaps you can pose this question with your drawing to Dr.McCulloch to see whether your picture and analogy of cosine thrust can be related to his theoretical explanation. I can't comment on that.
I am interested in Dr. McCulloch's equation regarding mathematically modeling the experiments. Regarding the Unruh wave explanation, I have a problem with mathematically justifying the required acceleration, as I have posted.
EDIT: It is interesting that in Shawyer's superconducting EM Drive design he has considerably reduced the ratio of the radial length "L" of the cavity with respect to the "diameters of the bases".
Previous Shawyer's design and NASA Eagleworks frustum approximately L = BigDiameter and L > SmallDiameter
in Shawyer's new design L < BigDiameter and L < SmallDiameter
this now is closer to meeting the required acceleration as one needs to meet:
(Diameter/(CavityLength) > 4 -
#2359 by Rodal on 20 Oct, 2014 21:16
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I just posted this in Dr. McCulloch's blog:
Although Shawyer does not describe the cavity mode shapes the cavity is resonating at, Brady et.al. does. Brady et.al (NASA) used COMSOL Finite Element analysis to analyze the mode shapes. It is interesting that Brady et.al (A and B in your table above) in your table correspond to the TRANSVERSE MAGNETIC field mode shape TM211, while Brady et.al. (C in your table above) corresponds to the TRANSVERSE ELECTRIC field mode shape TE012.
The TRANSVERSE ELECTRIC mode shape (TE012) resulted in 7 to 4 times greater thrust force/PowerInput than the TRANSVERSE MAGNETIC mode shapes (TM211).
See attached (electric field in red and magnetic field in blue):
: