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#3820 by Rodal on 19 May, 2015 23:10
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...Personally, I do not find Shawyer's equation to be that far off. I agree, his theory is flawed if you consider only perfectly conducting walls and group velocity. But, given asymmetrical losses, his assumption that F2 - F1 > 0 is exactly what it is. Two forces that are not exactly equal, opposing each other. The "how and why" are debatable, but the reality of it is not. Had someone done a Buckingham Pie Theory analysis of this, just based on input variables, the Max. potential thrust, 2*Q*P/c multiplied by an unknown Df based on the geometry, and whose value is to be experimentally determined, is exactly what you should get.
Right on !
Todd D.
Actually, there are three expressions, independently derived, with different physical models:
Shawyer
McCulloch
Notsosureofit
With similar dependence on P and Q
F = (P*Q / c ) * parameter
and of course, the expression P/c is in common with a photon rocket.
The three expressions just differ on the value of the parameter. Concerning a Buckingham Pie Theory Dimensionless analysis, this was done in EM Drive Thread 1, where frobnicat wrote a computer program to compare hundreds of equations to the experimental data, and it turns out that this form of expression (common to Shawyer, McCulloch and Notsosureofit) was a natural outcome of the analysis.
For the skeptic in me, P is directly related to heat, the surprising parameter is Q which is not related to heat. -
#3821 by rfcavity on 19 May, 2015 23:14
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Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.
I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.
With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.
Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Guess you have not read the Chinese data:
http://www.emdrive.com/NWPU2010translation.pdf
http://www.emdrive.com/NWPU2010testresults.pdf
http://www.emdrive.com/yang-juan-paper-2012.pdf
The thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
as a quick way to dismiss their results.
A.single paper is not a magic wand which causes all previous results to disappear. It cannot chan ge the tens of thousands of previous measure ments that have taken place in the last 50years. How do you refute cavities in pillbox shape that are used in GPS satellite atomic clocks? These have been characterized down to sub nanowatt levels, and no mystery power draw is observed and no thrust is observed in the GPS satellites (the location of which must be known very well.)
I don't refute the past nor existing devices as you should not. However that does not say they are all that is possible or that we know all possible variations of the theories thus embodied.
There is not a single paper, there are many.
Before signing a license deal with SPR, involving both the US and UK governments, Boeing would have crawled all over the SPR, all their devices, test rigs and especially the Demonstrator Engine and its static and dynamic test rigs. As part of that license deal, SPR built, tested and shipped the Flight Thruster to Boeing. SPR's claims for the results of the Flight Thruster are well known to Boeing. Never heard Boeing claim the Flight Thruster did not meet contract conditions.
BTW on the EagleWorks slide showing the various SPR devices, the Flight Thruster is labelled as a "High Fidelity Test Article". As the slide is from NASA. I'm sure SPR did not write that on the slide.
Just maybe something is happening that is inside the existing theories, yet largely unrealised. Both the Chinese and SPR state no new physics is needed and both CofE and CofM are conserved. Their theory math supports their claims and as well the theory math predicts the thrust they measured in 3 different ways.
It doesn't matter what Boeing or SPR does, they can't change physics.
Any portion of an atomic clock has been characterized to a degree many magnitudes greater than any of these test setups demonstrate. Just ask NIST. Unexpected results that have a divergence of the magnitude the papers you posted have claimed would have been identified during their development.
If you so strongly believe that these are happening, the timing on the GPS satellites have no correction for the effects observed from Eagleworks and the Chinese lab. Therefore, you should not use GPS receivers or trust any computer time that receives its time from NIST (basically most computers connected to the internet) until this 'new physics' is characterized. Because it would have a huge effect on those calculations. -
#3822 by WarpTech on 19 May, 2015 23:14
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...
It has not been ignored.
Sgawyer has discussed the TC and time to recharge the cavity energy lost to kinetic.
His superconducting space plane uses 8 EM Drives, arranged like 2 side by side 4 cylinder inline motors, driven in short pulses of less than 1 TC and phased apart to deliver continuous thrust.
If the thruster had 2 compartments, a cylinder, where resonance was easy to establish at high Q, and a long frustum designed for maximum attenuation connected at one end of the cylinder. Between the two, there is a "shutter" that can rapidly open and close. When closed, the cylinder resonates as a cylinder. When open, energy expands into the frustum chamber where it is attenuated. After the shutter closes again, the energy in frustum attenuates and energy in cylinder recharges.... repeat. I keep looking for ways to decouple the resonant amplifier from the attenuator.
Todd -
#3823 by Notsosureofit on 19 May, 2015 23:29
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Any portion of an atomic clock has been characterized to a degree many magnitudes greater than any of these test setups demonstrate. Just ask NIST. Unexpected results that have a divergence of the magnitude the papers you posted have claimed would have been identified during their development.
If you so strongly believe that these are happening, the timing on the GPS satellites have no correction for the effects observed from Eagleworks and the Chinese lab. Therefore, you should not use GPS receivers or trust any computer time that receives its time from NIST (basically most computers connected to the internet) until this 'new physics' is characterized. Because it would have a huge effect on those calculations.
The "Notsosureofit" formula mentioned above, was derived from, and is consistent with, the behavior of clocks in a gravitational field (ie accelerating frame of reference). Whether the force is zero or not remains to be seen.
I suppose I should add that these dispersion effects are well known at optical wavelengths and have been used a anti-reflection surfaces both by varying the dielectric constant and by nano-sized conical resonators. (probably the cone receptors in the eye as well but I'm no biologist) -
#3824 by deltaMass on 19 May, 2015 23:42
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And in other news, our Roumanian pal Iulian has gone silent.
http://www.masinaelectrica.com/emdrive-independent-test/ -
#3825 by Rodal on 19 May, 2015 23:48
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And in other news, our Roumanian pal Iulian has gone silent.
Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report
...
_____
Seriously speaking, I hope that Iulian is OK, and is getting the necessary, safe, protection -
#3826 by snow on 20 May, 2015 00:00
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And in other news, our Roumanian pal Iulian has gone silent.
Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report
...
he could have hurt himself. he was using no protection and was asked to rotate the thing a few times. -
#3827 by LasJayhawk on 20 May, 2015 00:00
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The cesium beam standards on the GPS satellites runs slow in space as compared to earth, and is corrected for.
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#3828 by deltaMass on 20 May, 2015 00:15
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Which is to say that you've missed the point being made about GPS systems.
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#3829 by deltaMass on 20 May, 2015 00:19
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Just to disambiguate that, if I may - he was asked a few times to rotate it to an upside down orientation once.And in other news, our Roumanian pal Iulian has gone silent.
Iulian is a shining example to us all (myself included) as Iulian works silently and humbly and posts only when he has something new to report
...
he could have hurt himself. he was using no protection and was asked to rotate the thing a few times. -
#3830 by VAXHeadroom on 20 May, 2015 00:31
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I was wondering if we would be able to get a faster turnaround with prototyping and maybe even cut costs if we could use 3D printing and e.g. conductive graphene filament like this one:
We could share computer designs and use local 3D printing services. Would that work?
That's what I've been planning on doing. Makes construction a great deal simpler for some of the pieces. I'm getting the bottom plate printed in aluminum and I will drill and tap the bolt holes myself. This makes it much easier to create the spherical concave surface.
Probably more useful to use ABS or PLA and make forms over which to construct other cavities for testing.
- been lurking for a few days and reading a LOT, you finally asked a question about which I have some expertise
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#3831 by LasJayhawk on 20 May, 2015 00:47
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Which is to say that you've missed the point being made about GPS systems.
No, not really. We have to correct for relativistic effects, but still have a margin of error.
Fun fact: the GPS satellites all gave gamma ray detectors on them. -
#3832 by deltaMass on 20 May, 2015 01:01
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Which is to say that you've missed the point being made about GPS systems.
No, not really. We have to correct for relativistic effects, but still have a margin of error.
Fun fact: the GPS satellites all gave gamma ray detectors on them.
I mean thisQuote from: rfcavityIt doesn't matter what Boeing or SPR does, they can't change physics.
Any portion of an atomic clock has been characterized to a degree many magnitudes greater than any of these test setups demonstrate. Just ask NIST. Unexpected results that have a divergence of the magnitude the papers you posted have claimed would have been identified during their development.
If you so strongly believe that these are happening, the timing on the GPS satellites have no correction for the effects observed from Eagleworks and the Chinese lab. Therefore, you should not use GPS receivers or trust any computer time that receives its time from NIST (basically most computers connected to the internet) until this 'new physics' is characterized. Because it would have a huge effect on those calculations. -
#3833 by Notsosureofit on 20 May, 2015 01:07
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Which is to say that you've missed the point being made about GPS systems.
No, not really. We have to correct for relativistic effects, but still have a margin of error.
Fun fact: the GPS satellites all gave gamma ray detectors on them.
Another fun fact: if you go to the Wikipedia page for GPS satellites and look at the equation for delta(1/gamma) you might see some similarity to spherical cavity ends.
http://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System#Relativity
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#3834 by Rodal on 20 May, 2015 01:28
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http://en.wikipedia.org/wiki/Global_Positioning_System#Spherical_cones
The solution space [x, y, z, b] can be seen as a four-dimensional geometric space. In that case each of the equations describes a spherical cone, with the cusp located at the satellite, and the base a sphere around the satellite. The receiver is at the intersection of four or more of such cones.
Stereographic projection of a spherical cone's generating lines (red), parallels (green) and hypermeridians (blue). Due to conformal property of Stereographic Projection, the curves intersect each other orthogonally (in the yellow points) as in 4D. All curves are circles or straight lines. The generatrices and parallels generates a 3D dual cone. The hypermeridians generates a set of concentric spheres. -
#3835 by phaseshift on 20 May, 2015 01:35
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This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
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#3836 by phaseshift on 20 May, 2015 01:39
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Both end plates are reversible - one side is flat the other spherical - for testing.
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#3837 by Rodal on 20 May, 2015 02:16
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This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
That is a really impressive job!
I have recalculated the small diameter, using Shawyer's paper http://www.emdrive.com/IAC-08-C4-4-7.pdf, see page 7, where Shawyer statesQuote from: ShawyerThe engine was built to operate at 2.45 GHz, with a design factor of 0.844 and has measured Q of 45,000 for an overall diameter of 280 mm.
(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
I have used this information
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
Design Factor = 0.844,
and inverted the equation for the Design Factor (see: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) to obtain the following correct dimension:
small diameter = 0.09613 m
Therefore, the dimensions should be corrected as follows
rfFrequency=2.45*10^9;
cavityLength=0.345; (ESTIMATED from Photographs)
bigDiameter=0.28 m; (provided by Shawyer)
smallDiameter= 0.09613 m; (obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
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#3838 by phaseshift on 20 May, 2015 02:33
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This is a 3D model of the "Shawyer Demo". I built it as close as I can figure that it has to be and examining the several photographs that have been shared here. The dimensions are from published values.
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
While this is a crude SketchUp model if anyone wants the model I'm happy to share it.
That is a really impressive job!
I have recalculated the small diameter, using Shawyer's paper http://www.emdrive.com/IAC-08-C4-4-7.pdf, see page 7, where Shawyer statesQuote from: ShawyerThe engine was built to operate at 2.45 GHz, with a design factor of 0.844 and has measured Q of 45,000 for an overall diameter of 280 mm.
(Unfortunately, Shawyer does not provide the small diameter or the cavity length in his paper)
I have used this information
bigDiameter = 0.28 m;
f = 2.45*10^9 Hz;
cst = 1.7062895542683174;
cM = 299705000 m/s (speed of light in air);
Design Factor = 0.844,
and inverted the equation for the Design Factor (see: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110 ) to obtain the following correct dimension:
small diameter = 0.09613 m
Therefore, the dimensions should be corrected as follows
rfFrequency=2.45*10^9;
cavityLength=0.345; (ESTIMATED from Photographs)
bigDiameter=0.28 m; (provided by Shawyer)
smallDiameter= 0.09613 m; (obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
I believe the dimensions I used were published and copied here to the forum some time ago - I don't recall the source and I'm sure it would take awhile to find the original post - here are the dimensions as posted though (I had copied to a file)
Notice that the force per power input reported by Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives". Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:
reported measurement ForcePerPowerInput (milliNewtons/kW)
(* Cannae Superconducting *) 761.9 to 952.4
(* Shawyer Demo *) 80 to 243
(* Shawyer Experimental *) 18.82
(* Brady c TE mode *) 21.31
(* Brady a TM mode*) 5.396
(* Brady b TM mode*) 3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176
lengths in meter
rfFrequency in 1/second (microwave frequency during test)
power in watts
force in milliNewtons
force per PowerInput in milliNewtons/kW
c= 299705000 m/s (speed of light in air)
c= 299792458 m/s (speed of light in vacuum) (for Cannae Superconducting)
(the difference between c in air compared to c in vacuum is negligible)
Note: SmallDiameter for Shawyer's EM Drives obtained from his reported ShawyerDesignFactor .
Force/PowerInput of a Photon Rocket = 1 / c
(* Cannae Superconducting *)
rfFrequency = 1.047*10^9;
cavityLength = 0.01+0.004+0.006+0.01 = 0.03;
bigDiameter =(22.86-2*(0.00430)) = 0.220;
smallDiameter = bigDiameter-2*0.01=0.200;
power = 10.5
Q = 1.1*(10^7)
measured force = 8 to 10
measured ForcePerPowerInput = 761.9 to 952.4
Force/PowerInput of a Photon Rocket =0.003336
measured ForcePerPowerInput to the one of a photon rocket = 228,400 to 285,500
(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;
bigDiameter=0.16;
smallDiameter=0.127546;
power = 850
Q = 5900
measured force = 16
measured ForcePerPowerInput = 18.82
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =5,640
(* Shawyer Demo *)
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853
power = 421 to 1200
Q = 45000
(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )
measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830
All Brady cases have the following dimensions:
cavityLength=0.332;
bigDiameter=0.397;
smallDiameter=0.244;
(* Brady a TM mode*)
rfFrequency=1.9326*10^9;
power = 16.9
Q = 7320
measured force = 0.0912
measured ForcePerPowerInput = 5.396
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =1,617.2
(* Brady b TM mode*)
rfFrequency=1.9367*10^9;
power = 16.7
Q = 18100
measured force = 0.0501
measured ForcePerPowerInput = 3.000
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =899.12
(* Brady c TE mode *)
rfFrequency = 1.8804*10^9;
power = 2.6
Q = 22000
measured force = 0.05541
measured ForcePerPowerInput = 21.31
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =6,386.7
(* Fearn, Zachar, Woodward & Wanser*)
rfFrequency = 39,300;
power = 170
measured force = 0.002
measured ForcePerPowerInput = 0.01176
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 3.526
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As it is my intention to duplicate Shawyer's model first I need to go with his dimensions - though now I want to verify where these dimensions came from.
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#3839 by phaseshift on 20 May, 2015 02:38
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If I knew the dimensions of the Chinese device, or perhaps the Boeing device, I would just as soon use them. Now that I have a script that can render any model from parameters I can play around for a while and see what I like.
