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#440 by flux_capacitor on 13 Aug, 2015 16:11
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How did you determine the very wide angle for this setup?
If the attenuation keeps growing with the angle, you would end up with 90° half-cone angle, which doesn't make sense.
Actually the 90° half-cone angle, thus the perfect half-sphere, was the value and the shape I started from
I first chose Ds = 150 mm (to be just above the cylindrical cut-off diameter at 2.45 GHz),
and Db = 4x that value = 600 mm (arbitrarily, I just wanted to maximize the difference between the two end diameters).
So my "cavity" was at the beginning a perfect half-sphere of r2 = 300 mm… which could not resonate in TE013 mode (according to TT's spreadsheet) until I moved the ends a bit, slightly increasing the distance between them from 225 mm at the beginning to the optimal distance of 230.75 mm, keeping the end diameters constant. Hence the half-cone angle reduced from 90° initially to 77.18° after tweaking. -
#441 by rfmwguy on 13 Aug, 2015 16:30
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Mine too, but I'll revert back to my college days one more time
LATE NITE, past my bedtime.
Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
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#442 by SeeShells on 13 Aug, 2015 16:37
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Well you're younger than I am kiddo.
Mine too, but I'll revert back to my college days one more time
LATE NITE, past my bedtime.
Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time? 60...HA!
If I wake up early I might join in but don't count your chickens. -
#443 by flux_capacitor on 13 Aug, 2015 17:17
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I keep thinking about the idea I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
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#444 by Mulletron on 13 Aug, 2015 17:26
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Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072 -
#445 by rfmwguy on 13 Aug, 2015 17:43
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Too bad if you dont skype in...they mentioned they'd like to get more perspectives on builders and I mentioned you. Think if people hear realistic, serious stories on theory and build, it'll let them know its not a fringe element working on these things. Right now, my thought is many think it is another cold-fusion type device. Lots of notions to clear up. Seems like a good place to start...
Well you're younger than I am kiddo.
Mine too, but I'll revert back to my college days one more time
LATE NITE, past my bedtime.
Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time? 60...HA!
If I wake up early I might join in but don't count your chickens. -
#446 by Rodal on 13 Aug, 2015 18:05
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I keep thinking about the idea I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
This is a very interesting shape to test the outer limits of the theories and methods involved.
Due to the extreme spherical conical shape of this cavity, the limitations of the spreadsheet approach (that in a kludgy way intends to model a spherical cone as a large series of cylindrical waveguides) is more crudely exposed:
the natural frequency of mode TE013 is 2.132 GHz (instead of 2.45 GHz), a difference of 15% in frequency (for cone angles of 15 degrees the spreadsheet is 1 to 2% different from the exact solution)
It does resonate, and it resonates well:
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
although this is not much more than the Q calculated for the 30 degrees cavity, so it looks like there are diminishing returns after 30 degrees
I attach below the contour plots for
1) the magnetic field in the spherical radial direction
2) the electric field in the azimuthal circumferential direction
Note how distorted is the magnetic field in the spherical radial direction
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#447 by Flyby on 13 Aug, 2015 18:13
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Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
Thanks for explaining how you got to that "apparent random" angle...It makes sense now.
STL files are the preferred choice for 3dprinting...
It doesn't really matter because even if you model it with a nurbs modeler software package (smooth and continuous surfaces), in the end, an STL file is a format that only understands 3d points, so all the surfaces are automatically converted to polygons....hence always be an approximation of the real surface.
it is all a matter of conversion resolution then...
what would be the best placement for the waveguide entrance then?
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#448 by Rodal on 13 Aug, 2015 18:37
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I keep thinking about the idea I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
This is a very interesting shape to test the outer limits of the theories and methods involved.
Due to the extreme spherical conical shape of this cavity, the limitations of the spreadsheet approach (that in a kludgy way intends to model a sherical cone as a large series of cylinders) is more crudely exposed:
the natural frequency of mode TE013 is 2.132 GHz (instead of 2.45 GHz), a difference of 15% in frequency (for cone angles of 15 degrees the spreadsheet is 1 to 2% different from the exact solution)
It does resonate, and it resonates well:
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
although this is not much more than the Q calculated for the 30 degrees cavity, so it looks like there are diminishing returns after 30 degrees
I attach below the contour plots for
1) the magnetic field in the spherical radial direction
2) the electric field in the azimuthal circumferential direction
Note how distorted is the magnetic field in the spherical radial direction
And these are the 3D plots of
1) the magnetic field in the spherical radial direction
2) the electric field in the azimuthal circumferential direction
The longitudinal magnetic field is the important field: it makes it look like a manta ray spaceship
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#449 by Mr. Peter on 13 Aug, 2015 18:52
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Quote from: Rodal
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
Hello sir.
I'm just lurking here. Appreciation for all the work you sir and all you guys do for emdive community.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
Could the inner portion of the cavity be lined with YBCO thin film and N2 cooled? Does YBCO film do the job at 2.3G or 23G freq?
Best, Peter
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#450 by Rodal on 13 Aug, 2015 19:08
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Welcome to the forum !Quote from: Rodaltheoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
Hello sir.
I'm just lurking here. Appreciation for all the work you sir and all you guys do for emdive community.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
Could the inner portion of the cavity be lined with YBCO thin film and N2 cooled? Does YBCO film do the job at 2.3G or 23G freq?
Best, Peter
Concerning operation of the cavity in the superconducting range, in my humble opinion that is way too complicated to give a thoughtful answer without doing the pertinent analysis, which I haven't done.
Shawyer claims to have been working on superconducting designs for years, but the very limited financial situation of his company reported in a number of posts by WallofWolfStreet in this forum (reported by WWS to be deeply in debt to hundreds of thousand of pounds, not a single employee, etc.) and the lack of experimental measurements (his latest paper in Acta Astronautica dealt mainly with futurustic designs) does not show progress that can be independently assessed. -
#451 by Rodal on 13 Aug, 2015 19:23
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...
For the 30 degree superconducting cavity Shawyer is entering asymmetrically from the lateral conical surface:
what would be the best placement for the waveguide entrance then?
see above image -
#452 by flux_capacitor on 13 Aug, 2015 19:48
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What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
I wonder this exactly since the beginning. After proving this technology is genuine (we're not sure for now) I think we could get high thrust from a cooled frustum, not necessarily superconducting, but just copper cooled with liquid nitrogen. I don't know if the Q would increase (?) but the power could certainly ramp up.
TT's spreadsheet, from Shawyer's advice and using Shawyer's thrust formulae, predict above 1.2 N of force for 2 kW of input power by a design similar to the one I've posted. Yang already used 2.5 kW on a non-superconducting, non-cooled copper frustum in ambient air. So with liquid nitrogen we could go way beyond that! -
#453 by Mr. Peter on 13 Aug, 2015 20:01
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Mr. Rodal, thank you for explanation.
Do you think that cooling copper/silver frustum with N2 might increase the Q-factor? I guess, in that case, the resistivity of copper might be reduced by a factor of 8, but I don't know, 2.4 Gig or even 24Gig is quite high and emdrive cavity is not a standard one.
So what do you thing about N2 cooling in order to gain the Q?
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#454 by WarpTech on 13 Aug, 2015 20:02
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Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Cool! The first section is equivalent to the PV Model of gravity, which I have been attempting to correlate to the waveguide physics. This paper appears to do exactly that!
Thank you! Good find!
Todd
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#455 by TheTraveller on 13 Aug, 2015 20:20
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Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
http://www.publications.parliament.uk/pa/cm200607/cmhansrd/cm061205/text/61205w0031.htm Scroll to almost the bottom.QuoteElectromagnetic Relativity Drive
Alan Duncan: To ask the Secretary of State for Trade and Industry how much his Department has provided to the electromagnetic relativity drive design proposed by Roger Shawyer; and from what budget funding has been drawn. [103254]
Margaret Hodge [holding answer 27 November 2006]: Awards have been made to Satellite Propulsion Research Ltd from the DTI’s Small Firms and Enterprise budget.
July 2001—£43,809 paid.
A feasibility study into the application of innovative microwave thruster technology for satellite propulsion. The study involved development of an experimental thruster followed by independent tests and evaluation
August 2003—£81,291 total grant awarded, £68,399 paid to date.
A follow-on from the above project, to design and develop a demonstration model engine. To be tested on a dynamic test rig, to demonstrate continuous thrust and the conversion of thrust into kinetic energy.
Both grants were awarded against the criteria of the DTI’s Smart scheme that was designed to help fund pioneering and risky R and D projects in small and medium enterprises.
Highly qualified technical experts and academics carried out an assessment on behalf of the Department.
Bolding added.
1st & 2nd funding was for Shawyer's Experimental EMDrive:
http://emdrive.com/feasibilitystudy.html
3rd & 4th funding, not mentioned, was awarded for the Demonstrator EMDrive and rotary test rig:
http://emdrive.com/demonstratorengine.html
http://emdrive.com/dynamictests.html (longer video is on the home page)
Seems both EMDrives were independently tested and passed a UK gov review panel as the report shows.
Really like those statements:
1) The study involved development of an experimental thruster followed by independent tests and evaluation
2) Highly qualified technical experts and academics carried out an assessment on behalf of the Department -
#456 by venir on 13 Aug, 2015 20:37
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Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
Long time lurker here, but to me this statement is not what the link you quote states at all. It states only that technical and academic experts carried out an assessment of the claims and were involved with the tests. At no point does it state what the result of that review was. -
#457 by TheTraveller on 13 Aug, 2015 20:40
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Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
Long time lurker here, but to me this statement is not what the link you quote states at all. It states only that technical and academic experts carried out an assessment of the claims and were involved with the tests. At no point does it state what the result of that review was.
The results was SPR got the funding from the UK gov to both build the Experimental EMDrive and the later much more complex Demonstrator EMDrive and the rotary test rig.
More data here attached. Pages 10 - 14.
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#458 by Mr. Peter on 13 Aug, 2015 20:41
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What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
I wonder this exactly since the beginning. After proving this technology is genuine (we're not sure for now) I think we could get high thrust from a cooled frustum, not necessarily superconducting, but just copper cooled with liquid nitrogen. I don't know if the Q would increase (?) but the power could certainly ramp up.
TT's spreadsheet, from Shawyer's advice and using Shawyer's thrust formulae, predict above 1.2 N of force for 2 kW of input power by a design similar to the one I've posted. Yang already used 2.5 kW on a non-superconducting, non-cooled copper frustum in ambient air. So with liquid nitrogen we could go way beyond that!
Hello mr. flux_capacitor!
Yes, it's definitely worth to give it a go.
Btw, as far as I can tell, you can get YBCO thin film for about $254, 15 pieces, 1cm2 each.
I guess those films are flexible to some degree.
The Rs is < 1 m Ohm @ 10 GHz, 77K, 0T, but I'm not sure if its fine at 24Gig.
If so, the superconducting babyEmdrive with its tiny cavity can be made.
Not cheap, but still, not arm and leg.
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#459 by mittelhauser on 13 Aug, 2015 23:05
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The results was SPR got the funding from the UK gov to both build the Experimental EMDrive and the later much more complex Demonstrator EMDrive and the rotary test rig.
More data here attached. Pages 10 - 14.
You are aware that the documents you are so happy about are from 7 years ago?!?
One of the biggest concerns about Sawyer's claims are that he hasn't provided reasonable proof in a decade (e.g. he hasn't even done a vacuum test!!!!).
The fact that they gave him money 7 years ago and nothing recently (as far as we know) is a HUGE indictment against his claims...
In other words, every time you post that type of thing, it makes me doubt more.
Which (to be clear - yet again) is a shame because I really want to believe.
My only hope now is that Sawyer stumbled upon something by accident and is just a lousy scientist and businessman - and some of the people in this thread (maybe even you TT) will produce some real evidence....
