Author Topic: EM Drive Developments Thread 1  (Read 762229 times)

Online Rodal

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Re: EM Drive Developments
« Reply #2180 on: 10/17/2014 05:31 PM »
@aero                                                                McCulloch's table
Demonstrator by ratio
w_big = 0.28 meters                                          0.28  meters        AGREE
w_small = 0.18375 meters                                 0.04 meters         DISAGREE
height = 0.2975 meters

Demonstrator by photo
w_big = 0.28 meters                                          0.28  meters        AGREE
w_small = 0.0778 meters                                 0.04 meters         DISAGREE Whatever works
height = 0.381 meters

Experimental by photo
w_big    0.16 meters                                      0.16 meters         DISAGRE Agree
w_small    0.0778 meters                                    0.08 meters         AGREE
height    0.177 meters


You don't think Shawyer just extended the big end of the Experimental model to make the Demonstrator model, do you?

For the Experimental Thruster, using Fig. 6 of Shawyer's report (http://www.emdrive.com/IAC-08-C4-4-7.pdf) I get:

Large Base Diameter = 16 cm = 0.16 m
Small Base Diameter = 11 cm = 0.11 m
Length = 15.8 cm = 0.158 m

Where is the photograph you used for Shawyer's demonstrator drive?
« Last Edit: 10/17/2014 05:36 PM by Rodal »

Online aero

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Re: EM Drive Developments
« Reply #2181 on: 10/17/2014 05:36 PM »
Quote
Where is the photograph you used for Shawyer's demonstrator drive?

At the bottom of the page here: http://emdrive.com/
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Online Rodal

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Re: EM Drive Developments
« Reply #2182 on: 10/17/2014 05:43 PM »
@aero                                                                McCulloch's table
Demonstrator by ratio
w_big = 0.28 meters                                          0.28  meters        AGREE
w_small = 0.18375 meters                                 0.04 meters         DISAGREE
height = 0.2975 meters

Demonstrator by photo
w_big = 0.28 meters                                          0.28  meters        AGREE
w_small = 0.0778 meters                                 0.04 meters         DISAGREE Whatever works
height = 0.381 meters

Experimental by photo
w_big    0.16 meters                                      0.16 meters         DISAGRE Agree
w_small    0.0778 meters                                    0.08 meters         AGREE
height    0.177 meters


You don't think Shawyer just extended the big end of the Experimental model to make the Demonstrator model, do you?



For the Shawyer Demonstrator Thruster, using the picture at the bottom of the page here: http://emdrive.com/ I get:



Large Base Diameter = 28 cm = 0.28 m
Small Base Diameter = 15.9 cm = 0.159 m (2 times @aero's estimate)
Length = 22.6 cm = 0.226 m

RelativeRatio = Large Base Diameter/Small Base Diameter = 1.76
Symmetrized Measure of Base Diameter Difference = ((RR-1)+(1/RR-1))= 0.329
(1/Small Base Diameter - 1/Large Base Diameter)=2.72 (1/m)

I think that the only length that is relevant in a truncated cone analysis is the length of the truncated cone itself and not the length of the cylinder attached to it, so "Length" means Length of truncated cone


For the Experimental Thruster, using Fig. 6 of Shawyer's report (http://www.emdrive.com/IAC-08-C4-4-7.pdf) I get:

Large Base Diameter = 16 cm = 0.16 m
Small Base Diameter = 11 cm = 0.11 m  (+41% greater than @aero's estimate)
Length = 15.8 cm = 0.158 m (-11% less than @aero's estimate)

RelativeRatio = Large Base Diameter/Small Base Diameter = 1.45
Symmetrized Measure of Base Diameter Difference = ((RR-1)+(1/RR-1))= 0.142
(1/Small Base Diameter - 1/Large Base Diameter)=2.84 (1/m)
« Last Edit: 10/17/2014 07:40 PM by Rodal »

Offline frobnicat

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Re: EM Drive Developments
« Reply #2183 on: 10/17/2014 05:54 PM »
Without Brady b, Here we go :

6 entries

Thresholds : mean=0.50   stddev=0.35

 a    b    L    Q    P    F    c                        mean   stddev
---------------------------------------------------------------------

 a    b    L    Q    P    F    c      exterm            mean   stddev
---------------------------------------------------------------------
a^0  b^-2 L^1  Q^1  P^1  F^-1 c^-1   (a^-1 + b^-1)^-1   0.49   0.29
a^2  b^-1 L^1  Q^1  P^1  F^-1 c^-1   (a^ 1 + b^ 1)^-2   0.19   0.27
a^1  b^-1 L^2  Q^1  P^1  F^-1 c^-1   (a^ 1 + b^ 1)^-2  -0.43   0.24
a^-1 b^-2 L^-1 Q^1  P^1  F^-1 c^-1   (a^-2 + L^-2)^-2   0.24   0.31
a^-2 b^-2 L^0  Q^1  P^1  F^-1 c^-1   (a^-2 + L^-2)^-2  -0.37   0.16
a^-2 b^-2 L^2  Q^1  P^1  F^-1 c^-1   (a^-2 + L^-2)^-1  -0.10   0.16
a^-1 b^-2 L^1  Q^1  P^1  F^-1 c^-1   (a^-1 + L^-1)^-2  -0.08   0.26
a^-1 b^-2 L^2  Q^1  P^1  F^-1 c^-1   (a^-1 + L^-1)^-1   0.35   0.20
a^0  b^-2 L^1  Q^1  P^1  F^-1 c^-1   (b^-1 + L^-1)^-1   0.33   0.26
a^-1 b^-2 L^2  Q^1  P^1  F^-1 c^-1   (b^-1 + L^-1)^-1  -0.28   0.35
a^-1 b^1  L^2  Q^1  P^1  F^-1 c^-1   |a^-2 - b^-2|^1   -0.07   0.29
a^0  b^0  L^1  Q^1  P^1  F^-1 c^-1   |a^-1 - b^-1|^1    0.24   0.25 <-
a^-1 b^0  L^2  Q^1  P^1  F^-1 c^-1   |a^-1 - b^-1|^1   -0.38   0.17
a^-1 b^-2 L^2  Q^1  P^1  F^-1 c^-1 sqrt(b^-1 L^-1)^-1   0.49   0.29

Checked : 94140625
Validated : 21769


Checked is number of all the combinations, Validated is number of formulas that respect dimensional consistency for kg m s units. Mean and standard deviation thresholds are lowered to yield approximately same number of selected formulas as previous run with all seven data points.

Relative values for MiHsC
(a^0  b^0  L^1  Q^1  P^1  F^-1 c^-1   |a^-1 - b^-1|^1 ) / mean value (without log)
  0.63   1.45   1.01   1.10   1.12   0.88
As per order Shawyer a & b, Juan 11 & 12, Brady a & c
This is quite good except Shawyer's results : should we skip those two outliers ?  :D
 
Rodal you are right that Q is more significant without Brady b : the Qless  F = 13100 P/c (a-b)^2/(ab)  no longer appears easily when relaxing mean constraint up to 12 (fudge factor in 163000 and 1/163000).
a^1  b^1  L^0  Q^0  P^1  F^-1 c^-1   |a^-1 - b^-1|^2   -9.63   0.46
is to be found amongst 200 formulas of similar or better levels of deviation.
It is not robust. But I still like it !

Waiting for adjusted inputs...
« Last Edit: 10/17/2014 05:55 PM by frobnicat »

Online aero

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Re: EM Drive Developments
« Reply #2184 on: 10/17/2014 05:58 PM »
Quote
I think that the only length that is relevant is the length of the truncated cone itself and not the length of the cylinder attached to it, so "Length" means Length of truncated cone

I don't know. I speculate that knowing the big diameter, we might be able to back the small diameter out of Shawyer's performance model using his published data. He does say that the thrust agrees with his performance model and it does use diameters of the ends of the cavity.

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Online Rodal

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Re: EM Drive Developments
« Reply #2185 on: 10/17/2014 05:58 PM »
...
This is quite good except Shawyer's results : should we skip those two outliers ?  :D
 
.....

What statistical argument can you use to state that those two are outliers?
« Last Edit: 10/17/2014 06:01 PM by Rodal »

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #2186 on: 10/17/2014 06:08 PM »
Quote
Where is the photograph you used for Shawyer's demonstrator drive?

At the bottom of the page here: http://emdrive.com/

Don't know if it's been mentioned, but the demo unit has a tuning plunger in the straight section.  You can see the motor and drive gears etc hanging out on the rear.

Offline frobnicat

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Re: EM Drive Developments
« Reply #2187 on: 10/17/2014 06:10 PM »
...
This is quite good except Shawyer's results : should we skip those two outliers ?  :D
 
.....

What statistical argument can you use to state that those two are outliers?

It was a sarcastical argument, not a statistical argument. I'm not seriously considering to lower the data count to 4 samples.

Online Rodal

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Re: EM Drive Developments
« Reply #2188 on: 10/17/2014 06:13 PM »
...
Waiting for adjusted inputs...
We still would like to hear whether there is an argument that can be made, explaining the formulas that model the experimental results either as:

A) an experimental artifact
B) a photon rocket

You can use the whole data (including the outlier) if you like to make the argument.   For the photon rocket argument I don't understand how the photons get out of the EM Drive and how does it get to do better than a perfect photon rocket.

Can you make an experimental artifact argument?
« Last Edit: 10/17/2014 06:19 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #2189 on: 10/17/2014 06:15 PM »
...
This is quite good except Shawyer's results : should we skip those two outliers ?  :D
 
.....

What statistical argument can you use to state that those two are outliers?
It was a sarcastical argument, not a statistical argument. I'm not seriously considering to lower the data count to 4 samples.
OK, but I wear my humorous hat only with Kernosabe  :)

But seriously, that Brady (b) is a statistical outlier on the basis of its deviation from the statistical cluster formed by the data without it.
« Last Edit: 10/17/2014 06:16 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #2190 on: 10/17/2014 06:30 PM »
Quote
I think that the only length that is relevant is the length of the truncated cone itself and not the length of the cylinder attached to it, so "Length" means Length of truncated cone

I don't know. I speculate that knowing the big diameter, we might be able to back the small diameter out of Shawyer's performance model using his published data. He does say that the thrust agrees with his performance model and it does use diameters of the ends of the cavity.

Do you agree that there is a cylindrical section to Shawyer's Demonstrator EM Drive that has the same diameter throughout? and that the diameter of this cylindrical section is the same as the diameter of the small base of the truncated cone? And therefore the smaller diameter at the end of the cavity is the same as the diameter of the small base of the truncated cone?

Did I miss something ?

If my logic above is not faulty, then our large discrepancy (a factor 2 between us ) is a matter of measurement and scaling.
One of us must be closest to the real answer ...

« Last Edit: 10/17/2014 08:17 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #2191 on: 10/17/2014 07:27 PM »
Another explanation for the EM Drive experimental findings based on a theory that allows electromagnetic fields to modify the space-time metric of General Relativity:

http://inspirehep.net/record/1220790/files/arXiv%3A1302.5690.pdf

http://arxiv.org/pdf/1310.5029.pdf

"Some axisymmetric electromagnetic modes of a truncated conical cavity are then presented
and used as source in the weak-field approximation of the equations, previously obtained,
to determine the force on the cavity. It is found that a coupling of the same magnitude
as used in [5] between the scalar  and the electromagnetic field results in a correct
magnitude and sign for the forces reported in asymmetric resonant cavities. ...The theory, however, does not seem to be completely satisfactory because in its linearized version it also predicts strong gravitational effects
by the Earth’s magnetic field, which are clearly not observed. A possible resolution of
this problem is considered in the last section."

"It was shown that the weak field approximation of a rather general scalar-tensor theory of
gravity, which includes an additional scalar with strong coupling to the electromagnetic
field, as proposed in[5], could account for the forces reported on asymmetric resonant
cavities. Although highly speculative, it is interesting that this was done using the
same coupling coefficient adjusted by[5] to explain discordant measurements of Newton
gravitational constant. It is also of interest that the inclusion of the external scalar 
can help to reconcile the Solar System tests with values of the Brans-Dicke parameter
close to unity (see relation (15)). The weakest part of the theory seems to be that
there is no clear way of preventing large gravitational effects due to the magnetic field
of the Earth, as predicted by Eq. (17). A possible solution can be sought in non-linear
effects,...Note that if this is possible for a static magnetic field, it could possibly not be the
case for a static electric field outside its sources, because the difference of sign would not allow real solutions.
It is so expected that static magnetic and electric fields show no unusual
gravitational effects, while non-stationary electromagnetic fields do. "



Online aero

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Re: EM Drive Developments
« Reply #2192 on: 10/17/2014 07:43 PM »
Quote
I think that the only length that is relevant is the length of the truncated cone itself and not the length of the cylinder attached to it, so "Length" means Length of truncated cone

I don't know. I speculate that knowing the big diameter, we might be able to back the small diameter out of Shawyer's performance model using his published data. He does say that the thrust agrees with his performance model and it does use diameters of the ends of the cavity.

Do you agree that there is a cylindrical section to Shawyer's Demonstrator EM Drive that has the same diameter throughout? and that the diameter of this cylindrical section is the same as the diameter of the small base of the truncated cone? And therefore the smaller diameter at the end of the cavity is the same as the diameter of the small base of the truncated cone?

Did I miss something ?

If my logic above is not faulty, then our large discrepancy (a factor 2 between us and a factor of 4 between my estimate and McCulloch's estimate) is a matter of measurement and scaling.  Of the photograph you and I are using is not the Demonstrator Drive, and Prof. McCulloch has better information as to what the dimensions of the Demonstrator Drive are?

One of us must be closest to the real answer ...



I don't know. I did post asking Prof M if he had better information. I also emailed Shawyer and Juan's university asking the same question. We will see if anyone responds.

I had assumed that the tapered cavity extended within the cylindrical section but you may be right. However, as was pointed out by Notsosureofit, it looks like there is some sort of mechanism in the cylindrical section. If there is a moveable small end, then I can't guess what the interior of the cylinder looks like.
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Offline Notsosureofit

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Re: EM Drive Developments
« Reply #2193 on: 10/17/2014 07:53 PM »
The upper gizmo is the motor and at the bottom it's driving a variable resistor as position feedback.  It probably was fed w/ a fixed frequency generator.
Hanging out the back is prob a limit switch.
« Last Edit: 10/17/2014 07:56 PM by Notsosureofit »

Online Rodal

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Re: EM Drive Developments
« Reply #2194 on: 10/17/2014 07:57 PM »
....
I don't know. I did post asking Prof M if he had better information. I also emailed Shawyer and Juan's university asking the same question. We will see if anyone responds.

I had assumed that the tapered cavity extended within the cylindrical section but you may be right. However, as was pointed out by Notsosureofit, it looks like there is some sort of mechanism in the cylindrical section. If there is a moveable small end, then I can't guess what the interior of the cylinder looks like.
Prof. McCulloch has answered that "I think I estimated 4cm using the design factor, probably wrongly. Your photographic method is better"

So it is up to us now to decide.  Can you please double check your diameter estimate? I double checked mine and it is 2 times your estimate for the small base of the Demonstrator
« Last Edit: 10/17/2014 08:05 PM by Rodal »

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #2195 on: 10/17/2014 08:11 PM »
For the O.D. of the copper straight section I get 18.8 cm if that helps  (using the pot as ref)

15.3 cm using the RF connector, but not sure of the right connector and worse camera angle,  sooo ?
« Last Edit: 10/17/2014 08:21 PM by Notsosureofit »

Online Rodal

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Re: EM Drive Developments
« Reply #2196 on: 10/17/2014 08:14 PM »
For the O.D. of the copper straight section I get 18.8 cm if that helps  (using the pot as ref)

Can you also please estimate the OD of the big diameter base end?

(Using your same method)

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #2197 on: 10/17/2014 08:28 PM »
For the O.D. of the copper straight section I get 18.8 cm if that helps  (using the pot as ref)

Can you also please estimate the OD of the big diameter base end?

(Using your same method)

29.6 cm for the pot
24.1 cm for the connector
still might have some camera distortion in that picture

(of course I'm comparing to parts I have here)
« Last Edit: 10/17/2014 08:31 PM by Notsosureofit »

Offline RotoSequence

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Re: EM Drive Developments
« Reply #2198 on: 10/17/2014 08:46 PM »
Another explanation for the EM Drive experimental findings based on a theory that allows electromagnetic fields to modify the space-time metric of General Relativity:

http://inspirehep.net/record/1220790/files/arXiv%3A1302.5690.pdf

http://arxiv.org/pdf/1310.5029.pdf

The proposed experiment looks exceptionally simple. Has this experiment been conducted? If there were positive results, the fringe forums would be ablaze with excitement over the possibilities.

I suspect that an experiment may have already been performed in the ten months since the paper was published, but due to the unpopularity of null results in scientific publishing, the results haven't made it very far.
« Last Edit: 10/17/2014 08:54 PM by RotoSequence »

Online Rodal

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Re: EM Drive Developments
« Reply #2199 on: 10/17/2014 08:57 PM »
Another explanation for the EM Drive experimental findings based on a theory that allows electromagnetic fields to modify the space-time metric of General Relativity:

http://inspirehep.net/record/1220790/files/arXiv%3A1302.5690.pdf

http://arxiv.org/pdf/1310.5029.pdf

The proposed experiment looks exceptionally simple. Has this experiment been conducted? If there were positive results, the fringe forums would be ablaze with excitement over the possibilities.

Don't know, but I agree that the experiment is simple and if it would be positive we should have heard about it.

Also, if one is going to posit an interaction of the EM Drive magnetic field, the first interaction one should explore is the interaction between the microwave cavity's magnetic field with the Earth's magnetic field.  This should be proportional to the Power Input.  One could also posit PowerInput*Q.  What I haven't determined is magnetic interaction with the Earth's field producing the required magnitude of forces, the direction, and the dependence on the diameters of the bases.  Waiting for frobnicat to help me with that...
« Last Edit: 10/17/2014 08:57 PM by Rodal »

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