Author Topic: EM Drive Developments Thread 1  (Read 763178 times)

Offline Mulletron

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Re: EM Drive Developments
« Reply #3120 on: 11/10/2014 11:50 PM »
Fun to play around with:
http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4

A torsion pendulum sim.
« Last Edit: 11/10/2014 11:58 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #3121 on: 11/11/2014 12:00 AM »
Fun to play around with:
http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4

Nothing is suspended from a wire:

Quote from: Brady, March, White, et.al.
The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup

NASA Eagleworks has an inverted pendulum.

According to Paul March, NASA Eagleworks uses as a torsional spring two Riverhawk C-flex bearing blocks with torsional spring constant


(http://flexpivots.com/cantilevered-single-ended-pivot-bearings/) centered 2.38" above and below the centerline of the 24.00" long by 1.50" Faztek aluminum pendulum arm. The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation. 





However, the NASA report shows a linear flexure bearing  http://flexpivots.com/linear-flexure-bearing/


Figure 1. Torsion Pendulum, Vacuum Chamber, and Linear Flexure Bearing
« Last Edit: 11/11/2014 12:48 AM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3122 on: 11/11/2014 12:36 AM »
« Last Edit: 11/11/2014 12:40 AM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Notsosureofit

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Re: EM Drive Developments
« Reply #3123 on: 11/11/2014 12:48 AM »
Fun to play around with:
http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4

Nothing is suspended from a wire:

Quote from: Brady, March, White, et.al.
The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup

NASA Eagleworks has an inverted pendulum.

According to Paul March, NASA Eagleworks uses as a torsional spring two Riverhawk C-flex bearing blocks with torsional spring constant


(http://flexpivots.com/cantilevered-single-ended-pivot-bearings/) centered 2.38" above and below the centerline of the 24.00" long by 1.50" Faztek aluminum pendulum arm. The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation. 

However, the NASA report shows a linear flexure bearing  http://flexpivots.com/linear-flexure-bearing/

Well, the pic shows the bearing block anyway, not neccesarily the c-flex which would be trapped between the two halves of the block  (always used c-flex meself back then)
« Last Edit: 11/11/2014 12:54 AM by Notsosureofit »

Online Rodal

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Re: EM Drive Developments
« Reply #3124 on: 11/11/2014 12:52 AM »
Fun to play around with:
http://amrita.vlab.co.in/?sub=1&brch=280&sim=1518&cnt=4

Nothing is suspended from a wire:

Quote from: Brady, March, White, et.al.
The pendulum arm pivots about two linear flexure bearings in a plane normal to gravitational acceleration. The flexure bearings provide an essentially-frictionless and hysteresis-free interface between the static test stand fixed structure and the dynamic pendulum arm. Test article force is measured by measuring the pendulum arm displacement and calculating the force via the flexure bearing spring constants that were determined during test facility setup

NASA Eagleworks has an inverted pendulum.

According to Paul March, NASA Eagleworks uses as a torsional spring two Riverhawk C-flex bearing blocks with torsional spring constant


(http://flexpivots.com/cantilevered-single-ended-pivot-bearings/) centered 2.38" above and below the centerline of the 24.00" long by 1.50" Faztek aluminum pendulum arm. The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation. 

However, the NASA report shows a linear flexure bearing  http://flexpivots.com/linear-flexure-bearing/

Well, the pic shows the bearing block anyway, not necc the c-flecs  (always used c-flex me self back then)

So, who are we to believe you think based on your experience and looking at the picture?  (Honest question, not a trick question)

The report that states linear bearing or Paul March that stated C-Flex bearing?
« Last Edit: 11/11/2014 12:53 AM by Rodal »

Online Notsosureofit

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Re: EM Drive Developments
« Reply #3125 on: 11/11/2014 12:59 AM »
C-Flex , no doubt about it.  The circular bore is a dead givaway,  made too many of 'em.

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #3126 on: 11/11/2014 01:02 AM »
1) The dynamic response of this structure (the EM Drive on the torsional pendulum) is governed by the ratio of the excitation frequency to the natural frequencies of the structure.

2) Mulletron stated that he didn't care about the natural frequency of the pendulum...

3) Mulletron was under the completely wrong understanding that the pendulum at NASA Eagleworks was a hanging pendulum...

4)  blah blah blah...

...what is unknown is the lumped mass (the EM Drive) at a given distance from the center of rotation.

5) Moreover, we don't need to know the mass to compute the dynamic response at all. ... [per] [Rodal], March, Frob, NotSo...

1)  Primitive man get that.  But the governance of these ratios and fequencies is dependent on the relatively massive additions to the torsional pendulum here and there along its structure.

IOW, an empty torsional pendulum will have a natual frequency 'x', and anatural frequency 'y' when loaded with stuff at various points.

2) Mulletron's was an unnecessary hissy fit, true.

3) That's what it seems from reading the back and forth.

4) rimitive man think there be too much certainty in such a dearth of factual experimental information.

Primitive man continue to ask if there is some way to model ranges of behavior.

5)  Which primitive man flat out do not get, and which p.m. look at with very wary eye.  (Vewwy wawwy, per Elmer Fudd)
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #3127 on: 11/11/2014 01:03 AM »
Hope this mention [of] prosecution will not [cause to be entertained] a certain level of paranoia : fact is, like for any rational investigation activity, hair splitting is also part of the job of science.

Nothing but admiration of your command of my native lingo; still, you seemed to have a few grammatical oddities which I believe I've corrected...

Quote from: Frob
I propose the hypothesis that the microwave amplifier is the cause of the lack of punch of the signal, if the amplifier takes more than .1s to reach full power.

Me think me disagree here somewhat.  Can't be that amp is starting from no current whasoever.  The amp must be operating from a standby mode, where it is ready to give as square a wave as it can as soon as it is triggered. 

Otherwise, there would have to be a warm-up period for the amp, where they would have to shunt the signal elsewhere, till it got up to spec.

But they were sloppy on the frequencies, as earlier noted, so what do me know?
« Last Edit: 11/11/2014 01:04 AM by JohnFornaro »
Sometimes I just flat out don't get it.

Online Rodal

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Re: EM Drive Developments
« Reply #3128 on: 11/11/2014 01:20 AM »
....
Quote from: Rodal
5) Moreover, we don't need to know the mass to compute the dynamic response at all. ... [per] [Rodal], March, Frob, NotSo...

....

5)  Which primitive man flat out do not get, and which p.m. look at with very wary eye.  (Vewwy wawwy, per Elmer Fudd)

I (and several competitors) analyzed and solved field dynamic problems much more complicated than this without having to know the mass or the stiffness of the vibrating machinery.  You go out on the field with vibration sensors (amplitude vs time) and perform a Fourier Transform of the data on the spot: you get power spectral density vs frequency.  Same way as I did here: using FFT to analyze the data.  Happens every day in the field.  Actually many customers have had for years built-in vibration monitoring that automatically outputs Power Spectral density vs frequency.

For problems that involve non-stationary response I use (time-frequency) Wavelet analysis.
« Last Edit: 11/11/2014 01:28 AM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3129 on: 11/11/2014 01:31 AM »
This whole "frequency" thing is a distraction from the actual issues raised on page 206, starting here: http://forum.nasaspaceflight.com/index.php?topic=29276.msg1286223#msg1286223

The word "frequency" was never mentioned by anybody until the very bottom of page 206.
Challenge your preconceptions, or they will challenge you. - Velik

Offline aero

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Re: EM Drive Developments
« Reply #3130 on: 11/11/2014 06:20 AM »
@Rodal - Did you write that the side walls of the cone are not subject to heating?

Because if the side walls did warm the outside boundary layer of air then the warmer boundary layer would rise causing a reduced pressure over the outside of the cone walls. The result would be a net force toward the small end.

Actually, I just glanced at the ideal gas law relationship and no easy way to calculate the lift force on the cone walls popped out. Its a constant pressure set-up because pressure is atmospheric, but total pressure includes dynamic pressure of the rising boundary layer. And of course the aerodynamic force is generated by the difference in static pressures caused by dynamic pressures. In this case with very low heating (small temperature change) the dynamic pressure would be very small. But then the cone walls are quite large so a very small pressure difference might create a small measured thrust.

Say 1/4 of the cone on each side contributed to aerodynamic normal force. The total area normal dot axial direction is big end area minus small end area divided by two (2*1/4). That is, about 193 cm2. Since F = P*A, to develop 50 micro N needs 0.00259067 N/m2 or 2.6 milli-Pa.

Dynamic pressure = rho*V2/2 and rho at sea level is about 1.225 kg/m3. It boils down to requiring a rising air velocity greater than  V ~ 6.5 cm/s which is probably to much to be generated quickly enough to avoid a tell-tale time lag in the measured signal.

It was just a thought.

This idea doesn't even consider the Cannae superconducting thruster, to which it could not apply.

« Last Edit: 11/11/2014 06:42 AM by aero »
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Online Rodal

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Re: EM Drive Developments
« Reply #3131 on: 11/11/2014 11:47 AM »
@Rodal - Did you write that the side walls of the cone are not subject to heating?

Because if the side walls did warm the outside boundary layer of air then the warmer boundary layer would rise causing a reduced pressure over the outside of the cone walls. The result would be a net force toward the small end.

Actually, I just glanced at the ideal gas law relationship and no easy way to calculate the lift force on the cone walls popped out. Its a constant pressure set-up because pressure is atmospheric, but total pressure includes dynamic pressure of the rising boundary layer. And of course the aerodynamic force is generated by the difference in static pressures caused by dynamic pressures. In this case with very low heating (small temperature change) the dynamic pressure would be very small. But then the cone walls are quite large so a very small pressure difference might create a small measured thrust.

Say 1/4 of the cone on each side contributed to aerodynamic normal force. The total area normal dot axial direction is big end area minus small end area divided by two (2*1/4). That is, about 193 cm2. Since F = P*A, to develop 50 micro N needs 0.00259067 N/m2 or 2.6 milli-Pa.

Dynamic pressure = rho*V2/2 and rho at sea level is about 1.225 kg/m3. It boils down to requiring a rising air velocity greater than  V ~ 6.5 cm/s which is probably to much to be generated quickly enough to avoid a tell-tale time lag in the measured signal.

It was just a thought.

This idea doesn't even consider the Cannae superconducting thruster, to which it could not apply.
For the transverse electric mode TE012 the electric field is circular, perpendicular to the long axis of the truncated cone.  The electric field is zero at the inner copper surface.  The only heating takes place because of the magnetic field in the long axial direction which heats the flat ends of the cone in circular areas centered at the center of the flat areas, as per attached picture.   Therefore there is no heating whatsoever of the round lateral surface of the cone.  Moreover, due to the Polyethylene insulation that Eagleworks placed at the interior small flat end, only the central portion of the big flat end gets all the power heating:

The following actions by NASA Eagleworks further maximized the increase in temperature of the flat ends:
1) They insulated the exterior surfaces of the flat ends of the cone by covering them with PCBoard polymer
2) They insulated the interior surface of the small flat end of the truncated cone by covering it with Polyethylene, which they called a  Quantum Vacuum dielectric.
3) Thus the only heated area under mode TE012 was a smaller central circular interior surface of the big flat end.
4) If the only copper surface at the big end was a 0.002 inch copper layer on the interior of the PCBoard (ref. @notSoSureOfIt) then this very thin copper would have served to significantly increase the temperature at the interior of the big flat end.

The Eagleworks truncated cone instead of pushing against the Quantum Vacuum is an inefficient heater heating a small central portion of the big flat end.  The steep force measured by Eagleworks is the inertial reaction due to this heating, that gets transmitted to the pendulum arm by the two bolts at the bottom of the PCBoard.

Electric field in Red
Magnetic field in Blue
« Last Edit: 11/11/2014 02:05 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3132 on: 11/11/2014 02:02 PM »


The test campaigns are discussed in the video too.

@39:25 the slide says the conical frustum has a 4" dielectric resonator!?!?!
« Last Edit: 11/11/2014 02:07 PM by Mulletron »
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Online Rodal

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Re: EM Drive Developments
« Reply #3133 on: 11/11/2014 02:11 PM »


The test campaigns are discussed in the video too.

@39:25 the slide says the conical frustum has a 4" dielectric resonator!?!?!

NASA Ames Research Director’s Colloquium, August 12, 2014.

discusses Infrared camera image of the Cannae test article at @36 minutes

Of course, as posted previously, there is no heating of the exterior round lateral surface of the cone.
White did not comment on interior heating of the big end or the insulation they placed on the exterior of the flat areas of the cone or the insulation they placed on the interior small end.

Observe that when White discusses the truncated cone TE012 test results he shows the electric field shown below (this seems to contradict the "Anomalous" report that states that this electric field is a calculation for the future truncated cone design ?)

White repeatedly discusses the initial results using TE012 mode without the dielectric they measured no thrust force and he says this is in agreement with this Quantum Vacuum theory.  White does not discuss the fact that the "dielectric" polymer insulates the interior surface small flat end from heating and thus all the heating is then concentrated on the big flat end interior surface.

White states that the test campaign results agrees with the Q-Thruster Quantum Vacuum Plasma White modeling (he does not use the word "plasma" though). Notice that White never addresses the fact that according to his previous publications the Q-Thruster force should be perpendicular to both the electric and magnetic fields, and therefore his predicted thrust force should be perpendicular to the actual measured force.

@52 minutes there are a few "softie" questions for about 8 minutes.  The "toughest" question asked is concerning the requirement for negative mass for the Alcubierre drive and where is this negative mass coming from.  White answers that it comes from the Quantum Vacuum.

Another question he answers is regarding conservation of momentum, he says that his theory predicts conservation of momentum because the Q-thruster is like a submarine using the water to propel itself and that he plans to measure the "Quantum Vacuum wake" by using another EM drive behind it.

He answers that the Alcubierre drive doesn't violate causality and that it cannot be used for time travel to the past because the spacecraft never travels faster than the speed of light in its local spacetime.
« Last Edit: 11/11/2014 03:01 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3134 on: 11/11/2014 03:07 PM »
There's no reason thermal effects and quantum effects can't both exist. Electronics get hot. The issue is which one is more?

Key points:
@45:20 dielectric importance in TE012 and ongoing
@54:15 conservation of momentum (saved by the qv bell, pushing off the qv? no way)

What's up with the disparity between the 4" dielectric slug from the slides and the reported 6.25"x1.06" slugs from the paper? Much inconsistency with this one.

Was dielectric important to TM211?

This thing really boils down to the limited understanding of the QV.

@56:00 @ 57:00, smart guy questions, I guess Dr. White is a negative vacuum energy kinda guy, as many are.

Dr. White seems to have realized he should curb his use of the word "plasma." Q-thruster is less likely to anger heavy hitter theoretical physicists, who know there is no such thing as a QV plasma.
Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #3135 on: 11/11/2014 03:14 PM »

....
What's up with the disparity between the 4" dielectric slug from the slides and the reported 6.25"x1.06" slugs from the paper? Much inconsistency with this one.

...
This inconsistency parallels the inconsistency of showing in his slide for the TE012 truncated cone test the electric field shown below, which in the "Anomalous" report is indicated to be the electric field of a future dielectric design and NOT the  tested design.

So, 4 inches must be diameter of the dielectric shown in this COMSOL Electric Field prediction.

« Last Edit: 11/11/2014 03:15 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3136 on: 11/11/2014 03:42 PM »
I'm wondering if someone screwed up while drafting the paper and those 6.25"x1.06" dielectrics are actually what is in Cannae. A tall narrow cylinder.

If the dielectric in the conical frustum is 4" (Tall or wide or both? What is supporting it?), we have our cavity estimates way off.

I'm not willing to bother anyone by emailing them for clarification. Anyone else already have a dialogue going?
« Last Edit: 11/11/2014 04:16 PM by Mulletron »
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Online Rodal

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Re: EM Drive Developments
« Reply #3137 on: 11/11/2014 05:01 PM »
I'm wondering if someone screwed up while drafting the paper and those 6.25"x1.06" dielectrics are actually what is in Cannae. A tall narrow cylinder.

If the dielectric in the conical frustum is 4" (Tall or wide or both? What is supporting it?), we have our cavity estimates way off.

I'm not willing to bother anyone by emailing them for clarification. Anyone else already have a dialogue going?
Equally (or more ?) likely that White conflated the new "dielectric" design and COMSOL FE analysis with the one used for actual testing by Brady and March as White rushed to present the Power Point presentation for the NASA Ames colloquium.

In the report one would have had to have the confluence of:

A) the several authors of the paper missing the dielectric mistake as opposed to just White making the mistake in his Ames presentation.

B) Probably more care would go into the AIAA paper and presentation, besides the multiple authors as opposed to an internal NASA presentation with only 8 minutes of questions

C) for the report there would have had to be several errors: the insert with the 6" dimension instead of 4" and most important the narrative that the COMSOL FE electric field is for a new design not yet tested.  It is unlikely that someone would refer to a future design unnecessarily.  More likely that White made the mistake in putting the Ames presentation together as Brady and March were the ones more involved in actual testing and this detail may not have been as vivid in White's mind compared to Brady and March.
« Last Edit: 11/11/2014 05:04 PM by Rodal »

Offline Mulletron

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Re: EM Drive Developments
« Reply #3138 on: 11/11/2014 06:14 PM »
This just goes to show that given the lack of detailed information, this stuff must be taken with a grain of salt and there is no point wasting steam going down the analytical rabbit hole and throwing numbers at ghosts. Even worse, it could lead us to the wrong conclusions.

The point of yesterday's "hissy fit".

Challenge your preconceptions, or they will challenge you. - Velik

Online Rodal

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Re: EM Drive Developments
« Reply #3139 on: 11/11/2014 06:25 PM »
Don't sermonize to others what they may be able to accomplish based on your own experience.

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