#### Mulletron

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##### Re: EM Drive Developments
« Reply #2040 on: 10/12/2014 05:42 PM »
We must be sure to understand that emdrive doesn't need MiHsC to work if dielectric thrust holds true. MiHsC is an optimization factor. Here on earth in strong gravity MiHsC's effect is essentially zero. Once in microgravity is it helpful. The effect is pretty much nothing otherwise unless you have fancy meta materials.
OK, let's analyze the meaning of "dielectric thrust"

To analyze this concept we need to specify what it entails.  Are you referring to the paper you quoted on chirality of the molecule and the quantum vacuum?  or are you referring to something else?

Thanks

The perceived importance of the dielectric media to the operation of the device. And yes. Also Dr. White's research on QVT.
Challenge your preconceptions, or they will challenge you. - Velik

#### Rodal

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##### Re: EM Drive Developments
« Reply #2041 on: 10/12/2014 05:46 PM »
I've attached a sketch of the Eagleworks cavity with the area ratios. Note that the base is 2.25 times larger than the throat. Does this mean that a particle oscillating between the base the throat at constant speed will impart 2.25 times the momentum on the throat as it does on the base?

Well and good, but if that particle has inertial mass of 1 unit as measured in the laboratory frame, what is it's inertial mass at the base? Of course it is 2.25 times that amount at the throat but what is the reference frame?

It is an important consideration because the answer will tell us how many oscillating particles are needed to produce the measured thrust.

For McCulloch's formula and for Shawyer's formula it is not only the ratio of the large and small flat areas that matter, but instead it is the dimensional difference of their reciprocals:

F = (PowerInput* Q / frequency) *(1/SmallDiameter- 1/LargeDiameter)

So you see, the dimensions of both surfaces enter the equation and not just their ratio

Of course, as it is obvious from the equation, they are inapplicable as the limit of SmallRadius --> 0 is approached, since the force goes to Infinity as that limit (a pointy cone) is approached.

EDIT: Also observe that it is not the surface area and it is not therefore the square of the radius of the flat surfaces that enters the formula but instead is the radius itself.
« Last Edit: 10/12/2014 10:03 PM by Rodal »

#### Rodal

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##### Re: EM Drive Developments
« Reply #2042 on: 10/12/2014 05:52 PM »
We must be sure to understand that emdrive doesn't need MiHsC to work if dielectric thrust holds true. MiHsC is an optimization factor. Here on earth in strong gravity MiHsC's effect is essentially zero. Once in microgravity is it helpful. The effect is pretty much nothing otherwise unless you have fancy meta materials.
OK, let's analyze the meaning of "dielectric thrust"

To analyze this concept we need to specify what it entails.  Are you referring to the paper you quoted on chirality of the molecule and the quantum vacuum?  or are you referring to something else?

Thanks

The perceived importance of the dielectric media to the operation of the device. And yes. Also Dr. White's research on QVT.

The chirality theory has been already dealt with.  It is not-explanatory due to the extremely small size of the effect predicted (nanometer per second velocity due to 10 Tesla magnetic field) and due to the fact that a 9 inch solid Teflon rod injection molded has practically no overall directionality and chirality.

It is much inferior to Prof McCulloch's theory as an explanatory theory from a quantitative and material viewpoint.
« Last Edit: 10/12/2014 05:54 PM by Rodal »

#### Mulletron

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##### Re: EM Drive Developments
« Reply #2043 on: 10/12/2014 05:56 PM »
We must be sure to understand that emdrive doesn't need MiHsC to work if dielectric thrust holds true. MiHsC is an optimization factor. Here on earth in strong gravity MiHsC's effect is essentially zero. Once in microgravity is it helpful. The effect is pretty much nothing otherwise unless you have fancy meta materials.
OK, let's analyze the meaning of "dielectric thrust"

To analyze this concept we need to specify what it entails.  Are you referring to the paper you quoted on chirality of the molecule and the quantum vacuum?  or are you referring to something else?

Thanks

The perceived importance of the dielectric media to the operation of the device. And yes. Also Dr. White's research on QVT.

The chirality theory has been already dealt with.  It is not-explanatory due to the extremely small size of the effect predicted (nanometer per second velocity due to 10 Tesla magnetic field) and due to the fact that a 9 inch solid rod injection molded has no directionality.

That's fine and all. The key point to get is that modified inertia doesn't make things move. It makes things easier to move. You still have to thrust against something in order to move.
Challenge your preconceptions, or they will challenge you. - Velik

#### Rodal

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##### Re: EM Drive Developments
« Reply #2044 on: 10/12/2014 06:01 PM »
We must be sure to understand that emdrive doesn't need MiHsC to work if dielectric thrust holds true. MiHsC is an optimization factor. Here on earth in strong gravity MiHsC's effect is essentially zero. Once in microgravity is it helpful. The effect is pretty much nothing otherwise unless you have fancy meta materials.
OK, let's analyze the meaning of "dielectric thrust"

To analyze this concept we need to specify what it entails.  Are you referring to the paper you quoted on chirality of the molecule and the quantum vacuum?  or are you referring to something else?

Thanks

The perceived importance of the dielectric media to the operation of the device. And yes. Also Dr. White's research on QVT.

The chirality theory has been already dealt with.  It is not-explanatory due to the extremely small size of the effect predicted (nanometer per second velocity due to 10 Tesla magnetic field) and due to the fact that a 9 inch solid rod injection molded has no directionality.

That's fine and all. The key point to get is that modified inertia doesn't make things move. It makes things easier to move. You still have to thrust against something in order to move.

Well, I rather pursue mathematical explanations rather than wordy explanations or wordy refutations.

Do you have a mathematical formula for what you call "Dr. White's QVT theory" to predict thrust force, so that we can compare it with Prof. McCulloch's formula and Shawyer's formula?

#### Rodal

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##### Re: EM Drive Developments
« Reply #2045 on: 10/12/2014 06:08 PM »
Is there a formula from Dr. White where the material constants and geometrical dimensions of the dielectric appear?
I don't recall any such "dielectric" material dependence in Dr. White's papers
« Last Edit: 10/12/2014 06:09 PM by Rodal »

#### Rodal

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##### Re: EM Drive Developments
« Reply #2046 on: 10/12/2014 06:14 PM »
From my knowledge, the formula from Prof. McCulloch's and the formula from Shawyer remain the only formulas that come close to predicting the experimental thrusts in the USA, UK and China experiments.  Everything else is orders of magnitude off.
« Last Edit: 10/12/2014 06:15 PM by Rodal »

#### MikeMcCulloch

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##### Re: EM Drive Developments
« Reply #2047 on: 10/12/2014 06:15 PM »
Just a note: MiHsC does predict movement. If you assume conservatn of m'tum, and change m, v changes. See my papers on the flyby anomaly (in MNRAS, 2008) or the Tajmar effect (in EPL, 2011).

#### Rodal

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##### Re: EM Drive Developments
« Reply #2048 on: 10/12/2014 06:25 PM »
Just a note: MiHsC does predict movement. If you assume conservatn of m'tum, and change m, v changes. See my papers on the flyby anomaly (in MNRAS, 2008) or the Tajmar effect (in EPL, 2011).
I agree 100%.  That's my reading of your papers, and you also make that clear in your blog.  It follows from conservation of momentum.

#### Mulletron

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##### Re: EM Drive Developments
« Reply #2049 on: 10/12/2014 06:47 PM »
From my knowledge, the formula from Prof. McCulloch's and the formula from Shawyer remain the only formulas that come close to predicting the experimental thrusts in the USA, UK and China experiments.  Everything else is orders of magnitude off.

The paper says clearly and provides data that the dielectric is key. The question is how.

Now on the flipside, with no dielectric present, you would get uneven heat of the cavity from fore to aft and some movement of the device. How else could it move? Internal stresses would convert to wall strain. Where is the reaction mass?
Challenge your preconceptions, or they will challenge you. - Velik

#### Rodal

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##### Re: EM Drive Developments
« Reply #2050 on: 10/12/2014 07:07 PM »
From my knowledge, the formula from Prof. McCulloch's and the formula from Shawyer remain the only formulas that come close to predicting the experimental thrusts in the USA, UK and China experiments.  Everything else is orders of magnitude off.

The paper says clearly and provides data that the dielectric is key. The question is how.

Now on the flipside, with no dielectric present, you would get uneven heat of the cavity from fore to aft and some movement of the device. How else could it move? Internal stresses would convert to wall strain. Where is the reaction mass?
OK, but that is an experimental finding by Brady et.al.  NASA presents no theory for it whatsoever.

As far as I know Dr. White has not published in the open literature a mathematical formula to predict "thust" from the dielectric.  The only such theory is the chirality paper that you uncovered, but unfortunately its prediction is several orders of magnitude off and furthermore a 9 inch solid Teflon rod that has been injection molded should have no directional chirality to exploit.

Furthermore, what they state is

<<There appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF resonator in the thrust chamber. The geometry, location, and material properties of this resonator must be evaluated using numerous COMSOLŪ iterations to arrive at a viable thruster solution. We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.>>

So, some "very early tests" at a significantly higher frequency with unknown Q.

Given the fact that they have other data showing one experiment given 10% less thrust with 6 times higher input Power, this "dielectric" stuff is not that paramount.

Also, the information from @wembley is that Shawyer no longer uses any dielectric.
« Last Edit: 10/12/2014 07:28 PM by Rodal »

#### aero

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##### Re: EM Drive Developments
« Reply #2051 on: 10/12/2014 07:52 PM »
I've attached a sketch of the Eagleworks cavity with the area ratios. Note that the base is 2.25 times larger than the throat. Does this mean that a particle oscillating between the base the throat at constant speed will impart 2.25 times the momentum on the throat as it does on the base?

Well and good, but if that particle has inertial mass of 1 unit as measured in the laboratory frame, what is it's inertial mass at the base? Of course it is 2.25 times that amount at the throat but what is the reference frame?

It is an important consideration because the answer will tell us how many oscillating particles are needed to produce the measured thrust.

For McCulloch's formula and for Shawyer's formula it is not only the ratio of the large and small flat areas that matter, but instead it is the dimensional difference of their reciprocals:

So you see, the dimensions of both surfaces enter the equation and not just their ratio

Of course, as it is obvious from the equation, they are inapplicable as the limit of SmallRadius --> 0 is approached, since the force goes to Infinity as that limit (a pointy cone) is approached.

EDIT: Also observe that it is not the surface area and it is not therefore the square of the radius of the flat surfaces that enters the formula but instead is the radius itself.

Quote
What if the resonant cavity walls acted like a Hubble horizon, especially for Unruh waves of a similar length (as they are in this case)? Then the inertial mass of the photons would increase towards the cavity's wide end, since more Unruh waves would fit there, since mi=m(1-L/2w), where w is the cavity width.

This looks to me like a 1-D derivation. More Unruh waves would also fit is a larger area, not simply on a 1-D line. The equation would look the same in 2-D, with area replacing width. With a little algebra the equation becomes
F = PowerInput*Q * (Large area-Small area)/(frequency*Large area*Small area)

Not quite what I had before but the area difference is explicit.
Retired, working interesting problems

#### Rodal

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##### Re: EM Drive Developments
« Reply #2052 on: 10/12/2014 07:59 PM »
I've attached a sketch of the Eagleworks cavity with the area ratios. Note that the base is 2.25 times larger than the throat. Does this mean that a particle oscillating between the base the throat at constant speed will impart 2.25 times the momentum on the throat as it does on the base?

Well and good, but if that particle has inertial mass of 1 unit as measured in the laboratory frame, what is it's inertial mass at the base? Of course it is 2.25 times that amount at the throat but what is the reference frame?

It is an important consideration because the answer will tell us how many oscillating particles are needed to produce the measured thrust.

For McCulloch's formula and for Shawyer's formula it is not only the ratio of the large and small flat areas that matter, but instead it is the dimensional difference of their reciprocals:

F = (PowerInput* Q / frequency) *(1/SmallDiameter- 1/LargeDiameter)

So you see, the dimensions of both surfaces enter the equation and not just their ratio

Of course, as it is obvious from the equation, they are inapplicable as the limit of SmallRadius --> 0 is approached, since the force goes to Infinity as that limit (a pointy cone) is approached.

EDIT: Also observe that it is not the surface area and it is not therefore the square of the radius of the flat surfaces that enters the formula but instead is the radius itself.

Quote
What if the resonant cavity walls acted like a Hubble horizon, especially for Unruh waves of a similar length (as they are in this case)? Then the inertial mass of the photons would increase towards the cavity's wide end, since more Unruh waves would fit there, since mi=m(1-L/2w), where w is the cavity width.

This looks to me like a 1-D derivation. More Unruh waves would also fit is a larger area, not simply on a 1-D line. The equation would look the same in 2-D, with area replacing width. With a little algebra the equation becomes
F = PowerInput*Q * (Large area-Small area)/(frequency*Large area*Small area)

Not quite what I had before but the area difference is explicit.

The derivation was indeed 1-dimensional.  Prof. McCulloch and I stated that it was 1-Dimensional at various times.

Concerning "fitting more Unruh waves" in a 2-D derivation , I think that it is not just a question of placing a dependence on area, but one would have to consistently account for and properly derive the dependence on:

1) The tapered section geometry (the angle of the cone)

2) 2-Dimensional mode shapes

in order to be a consistent 2-Dimensional analysis.
« Last Edit: 10/12/2014 10:03 PM by Rodal »

#### aero

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##### Re: EM Drive Developments
« Reply #2053 on: 10/12/2014 08:16 PM »
Probably true. The cone half angle is like 1.5/9, opposite/adjacent. That is arctan(1.5/9), or more precisely, 0.1813 radians.

Deriving the 2-D equations looks like a job for Dr. Rodal or Prof. M.

I wonder if it will make a difference in the acceleration required to establish the Unruh waves within the cavity?
Retired, working interesting problems

#### Mulletron

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##### Re: EM Drive Developments
« Reply #2054 on: 10/12/2014 08:55 PM »
New insights page 3.

http://arxiv.org/abs/1012.5264
Challenge your preconceptions, or they will challenge you. - Velik

#### Notsosureofit

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##### Re: EM Drive Developments
« Reply #2055 on: 10/12/2014 09:34 PM »
Apparantly the dielectric block in Figure 15. was just the starting point for the COMSOLanalysis iteration
process used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster.

From Figure 18:

"Cu Frustrum Test Configuration:
2, 6.25" x 1.06" PE Discs at small End"

#### Rodal

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##### Re: EM Drive Developments
« Reply #2056 on: 10/12/2014 09:39 PM »
Apparantly the dielectric block in Figure 15. was just the starting point for the COMSOLanalysis iteration
process used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster.

From Figure 18:

"Cu Frustrum Test Configuration:
2, 6.25" x 1.06" PE Discs at small End"

Fantastic information @notsosureofit   !!!!!

You determined the material:  Polyethylene  (PE)

and the dimensions 6.25" x 1.06"

apparently what they used was 2 (two?) solid disks 6.25 inches in diameter by 1.06 inches thick

There was apparently no inner hole, or they did not record the inner diameter in the report?
« Last Edit: 10/12/2014 09:41 PM by Rodal »

#### JohnFornaro

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##### Re: EM Drive Developments
« Reply #2057 on: 10/12/2014 10:13 PM »
I wonder if it will make a difference in the acceleration required to establish the Unruh waves within the cavity?

Who or what, with such confidence,  is "establishing" waves which have never been detected before?
Sometimes I just flat out don't get it.

#### Notsosureofit

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##### Re: EM Drive Developments
« Reply #2058 on: 10/12/2014 10:14 PM »
Apparantly the dielectric block in Figure 15. was just the starting point for the COMSOLanalysis iteration
process used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster.

From Figure 18:

"Cu Frustrum Test Configuration:
2, 6.25" x 1.06" PE Discs at small End"

Fantastic information @notsosureofit   !!!!!

You determined the material:  Polyethylene  (PE)

and the dimensions 6.25" x 1.06"

apparently what they used was 2 (two?) solid disks 6.25 inches in diameter by 1.06 inches thick

There was apparently no inner hole, or they did not record the inner diameter in the report?

Hmmm, goin to have to think back to the '50s when PE was used between Cu plates as HV capacitors.
« Last Edit: 10/12/2014 10:16 PM by Notsosureofit »

#### frobnicat

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##### Re: EM Drive Developments
« Reply #2059 on: 10/12/2014 10:44 PM »
.../...
For McCulloch's formula and for Shawyer's formula it is not only the ratio of the large and small flat areas that matter, but instead it is the dimensional difference of their reciprocals:

So you see, the dimensions of both surfaces enter the equation and not just their ratio

Of course, as it is obvious from the equation, they are inapplicable as the limit of SmallRadius --> 0 is approached, since the force goes to Infinity as that limit (a pointy cone) is approached.
.../...

This looks to me like a 1-D derivation. More Unruh waves would also fit is a larger area, not simply on a 1-D line. The equation would look the same in 2-D, with area replacing width. With a little algebra the equation becomes
(2)F = PowerInput*Q * (Large area-Small area)/(frequency*Large area*Small area)

Not quite what I had before but the area difference is explicit.

Dimensional analysis (sanity check)  (Q dimensionless) :
(1) kg m /sē = kg mē /s^3  s /m  OK
(2) kg m /sē != kg mē /s^3  mē s /mē /mē = kg /sē   the expression lacks a meter unit somewhere

Regarding (1) and divergence when SmallRadius tends to 0, regardless of the soundness of the backing explanation (I just plain don't get it) the scaling behaviour could be interpreted as :
- the smaller both radius (that is, the thinner the cavity, at constant LargeRadius/SmallRadius) the stronger the force (linearly). That sounds strange but :
- if we consider that the wavelength must fit into the SmallRadius then the thinner the cavity, the higher must be the frequency, so as to cancel the increase in thrust from a thinner design. This is less strange : at constant power and Q, a thinner cavity, half radius from a given design, could yield same thrust only by doubling the frequency.

A cone (SmallRadius=0) would be no more thrusting than truncated cone at SmallRadius ~ c / frequency (ie. 15.8 cm at 1.9GHz). That is c would appear somewhere in the formula as to asymptotically limit the divergence when going thinner...
But I don't understand the backing theory, this is just formal frobnicating.
« Last Edit: 10/12/2014 10:49 PM by frobnicat »

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