Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1803510 times)

Online SeeShells

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HxLarge
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Another observation: there has not been a single excitation of a TE mode in any MEEP run for Yang/Shell up to now.

Further exploration is required in order to find out how to excite TE modes using Meep.

Asymmetric location of the antenna just results in very asymmetric fields being excited.

I doubt it will fix it. The "rotation" looks more like simply reflections bouncing side to side, around a circle. 3 antenna will just have 3 overlapping sets of random reflections. We shall see...
Todd
I realize we are in a area of trying to hold onto a slippery fish of a resonate mode and the tighter we squeeze the easier it is for the fish to slip out. I'm looking forward to seeing the results of the meep run when aero does it. It may be we need to insert the loop halfway between the plates as the radiation pattern from a loop mimics a donut and equal on both sides of the loop and it could trap the modes. Still thinking that through but lets do this first one.

Shell

Online SeeShells

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...
I doubt it will fix it. The "rotation" looks more like simply reflections bouncing side to side, around a circle. 3 antenna will just have 3 overlapping sets of random reflections. We shall see...
Todd
To solve it, it is necessary to understand the fundamental mode shape one wants to excite: how the amplitude of the mode shape is supposed to vary along the intrinsic spherical coordinate system (certainly not the extrinsic Cartesian coordinate system).  The variation is governed by Associated Legendre Functions in the spherical polar angle, Spherical Bessel in the spherical radii, and Harmonic in the spherical azimuthal angle. 

The Cartesian system, and anything based on it is unnatural to the physical problem.
Dr. Rodal, I had to read that three times to pack that comment in. Well spoken.

shell

Online SeeShells

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Jose',

I'm ready to drop the brick, bury the hatchet and shake hands.

I have a dear friend who is a drummer and she is a phenomenal player and even won a Grammy, but to the band she is simply a knuckle dragging, bongo beating, grunting part of the band. We all know the drummer in a band is as important as any other member.

So I'm a drummer here with a hammer and a soldering iron and 50 years of building things trying to play with this group to make some beautiful music,  just don't laugh too much when I drag my knuckles.

Deal?

Shell

Online Rodal

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Jose',

I'm ready to drop the brick, bury the hatchet and shake hands.

I have a dear friend who is a drummer and she is a phenomenal player and even won a Grammy, but to the band she is simply a knuckle dragging, bongo beating, grunting part of the band. We all know the drummer in a band is as important as any other member.

So I'm a drummer here with a hammer and a soldering iron and 50 years of building things trying to play with this group to make some beautiful music,  just don't laugh too much when I drag my knuckles.

Deal?

Shell


Deal   :)

I'm on the road ... More later :)

Best regards

Offline TheTraveller

...

Cullen, Shawyer and Prof Yang are correct, as attached, to use the guide wavelength inside their waveguides (other side of the same coin as group velocity) to calc the end plate reflected Force generation.

Looking at the above-mentioned quotation by Yang you will notice that she mentions this as the introduction to her paper, for historical reasons, and that she does not actually support or much less use this in any of her calculations.   It is in section one of her paper, as a historical introduction, where she clearly states that this is what Roger Shawyer maintains and not her theory:



"Original idea..." "Roger Shawyer..." got it?  It is a historical introduction.  Just like a book about the quantum vacuum could start by mentioning the history of the super-rigid aether which was later proven to be wrong.

Get the difference?

 Tajmar starts his paper by quoting Shawyer's theory but is more up-front: in Tajmar's paper Tajmar makes it plain to distance himself from Shayer's "theory" calling it controversial ("pushing against itself" :)  ):

Quote from: Tajmar
It must be noted that Shawyers analysis and claims are highly controversial (e.g. Ref. 9) as this would obviously violate the conservation of momentum (pushing against itself) following his theory. Aside from the theoretical concept, most interesting are the experimental claims that have been published to date

Yang is more diplomatic, rather than saying that Shawyer's theory is controversial, she proceeds to develop her own theory: Yang never uses the group velocity in her calculations.  Yang uses a Finite Element formulation that dispenses with Shaweyr's theory.  Yang effectively throws Shawyer's theory to the dustbin: observe how Shawyer claims that there is no pressure on the sidewalls, while Yang shows that Shawyer is wrong as she calculates the pressure on the sidewalls and shows how important the pressure on the sidewalls is.

So far everybody has distanced themselves from Shaywer's "theory"  McCulloch has made it plain,  Tajmar also has distanced himself,  Yang is more diplomatic.  One has to understand Yang's formulation to understand that Yang also distances herself and rejects Shaywer's theory.  Yang is subtle: instead of saying how wrong Shawyer is with words, Yang uses equations.  One has to read Yang's paper beyond section one, and understand Yang's equations in order to understand how Yang rejects Shawyer's theory.

To be very clear Prof Yang never rejects nor refutes Shawyer's photon based theory. What see did was to explain how the Shawyer EMDrive works using classic electrodynamics.

She said:
Quote
In addition, the microwave thrusters can be explained using the classical electrodynamics theory.

As for Shawyer's use of Cullen 15, I guess you will now try to say either Shawyer or Cullen got it wrong?

In regard to Tajmar rejecting Shawyer, who was it Tajmar thanked for giving him assistance? Strange to reject a theory that just helped you build a frustum that produced Force.

BTW have you figured out how to properly calc resonance when the end plates are spherical and the resonant length is the distance between them?
« Last Edit: 08/05/2015 03:41 PM by TheTraveller »
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Offline Ricvil

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Many symmetry brokens can ocurrs  in the tapered cavity.
The position of the antenna inside cavity can broke the circular symmetry.
The loss of metal of cavity and gain of magnetron can broke parity-time  symmetry.
I'm no surprised if the fields inside cavity evolves to a bloch oscillation, both longitudinal and circular.
Would be interesting to seek for spatio-temporal oscillations of the center of mass of energy density inside cavity.
« Last Edit: 08/05/2015 05:01 PM by Ricvil »

Offline TheTraveller

When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

Shawyer says to use the diameter as the cutoff.
« Last Edit: 08/05/2015 03:27 PM by TheTraveller »
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Online SeeShells

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When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

Shawyer say to use the diameter as the cutoff.
Would that still be the case with this design? Or should I split the diff between the two?
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1053151;image

Offline TheTraveller

When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

Shawyer say to use the diameter as the cutoff.
Would that still be the case with this design? Or should I split the diff between the two?
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1053151;image

That design will introduce massive phase distortion when the spherical wave (concave at the small end) bounces off that concave small end plate. Much worse than a flat plate.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline Blaine

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Why is there still talk of cutoff? I thought this forum has carefully been over that there is no real cutt-off for tapered cavities like the EmDrive.  So, why are we back to this kind of talk?
Weird Science!

Disclaimer: My field-theoretical skills are decades rusty. But there is a thought that keeps bothering me for a while, that I wonder if I should share it here.
Here we go, even at the risk of totally embarrassing myself:

I was wondering what the importance of resonance is? What does it change in our concept?
I believe there are two aspects:

One is that is allows to add energy continuously that allows building up to a critical point. Like light amplification in a Laser.
That's what I feel we are focussing on, when we discuss resonance here.
But there is another aspect I believe. Resonance shapes a locally stable 4-dimensional "body" of energy. 4-dimensional because we have real and imaginary parts that depend on locality.
(I do remember calculating these field forms back in college and I was always flabbergasted about their weird physical forms.)

Now, when we discuss Conservation of Energy we work under the assumption of a 3-dimensional space.
Hence when we bounce energy in a closed system back and forth, both directions should cancel out. But what happens if we expand that thought to 4 dimensions (add the imaginary part)?

If we could physically shape a frustum complementary to our energy "body" in a way that exposes its surface only in areas of the real part in one direction and the imaginary part in the other direction, should we get a "thrust"?
We would not need new particles. We would only work with complex (real and imaginary) physical concepts we already know.

Is such construct even possible?

Online SeeShells

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When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

Shawyer say to use the diameter as the cutoff.
Would that still be the case with this design? Or should I split the diff between the two?
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1053151;image

That design will introduce massive phase distortion when the spherical wave (concave at the small end) bounces off that concave small end plate. Much worse than a flat plate.
Interesting...

Offline deltaMass

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Any comments on something else to monitor?

Filming both end plates with an IR camera to show mode shapes?
A field meter external to the box to see what kind of leakage, if any, is present. I don't think it's necessary to have that on the rotor if it's easier to sit it at a stationary place.

You might also want to think about control experiments with a dummy load. I already made a comment about that.

Offline CraigPichach

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Wow, that's a big find - thank you for posting this.

You think that is on the order of less than 20 micro-seconds? Wish could zoom in there.

I thought I read somewhere that there was a delay and some were attributing it to the need for the unit to vibrate though this seems to discount it (and opens up some doors).


In the NASA thrust data they seem to take seconds before seeing "thrust" on their Q-Thruster frustrums... any thoughts as to why the delay? Shouldn't this be occurring as soon as resonance is reached in an order of microseconds? Does it take them that long to reach resonance? Any thoughts?

To my knowledge (I may be wrong) Eagleworks didn't experience any significant delay after applying power and before measuring thrust. They used a solid-state RF amp that was already tuned for the matching resonant frequency of the cavity. See data available in the original paper, especially:

Figure 22. TE012 test data, quality factor of 22000, applied power of 2.6 watts, net average thrust of 55.4 micronewtons.

attached below. See "RF ON" in red applied for 30 seconds, with a thrust signature appearing when RF was switched on, and disappearing when switched off.

However I wonder what is the ~70N quick peak during a few seconds before the "net thrust" of ~60N.

You may mistake NASA's data with Shawyer's, who reported, using a magnetron:
Quote from: Roger Shawyer
The engine only starts to accelerate when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period.

I suspect the "warm up period" includes the fine tuning of the moveable small end plate through a stepper-motor, seeking for the correct resonant frequency.

Offline deltaMass

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Disclaimer: My field-theoretical skills are decades rusty. But there is a thought that keeps bothering me for a while, that I wonder if I should share it here.
Here we go, even at the risk of totally embarrassing myself:

I was wondering what the importance of resonance is? What does it change in our concept?
I believe there are two aspects:

One is that is allows to add energy continuously that allows building up to a critical point. Like light amplification in a Laser.
That's what I feel we are focussing on, when we discuss resonance here.
But there is another aspect I believe. Resonance shapes a locally stable 4-dimensional "body" of energy. 4-dimensional because we have real and imaginary parts that depend on locality.
(I do remember calculating these field forms back in college and I was always flabbergasted about their weird physical forms.)

Now, when we discuss Conservation of Energy we work under the assumption of a 3-dimensional space.
Hence when we bounce energy in a closed system back and forth, both directions should cancel out. But what happens if we expand that thought to 4 dimensions (add the imaginary part)?

If we could physically shape a frustum complementary to our energy "body" in a way that exposes its surface only in areas of the real part in one direction and the imaginary part in the other direction, should we get a "thrust"?
We would not need new particles. We would only work with complex (real and imaginary) physical concepts we already know.

Is such construct even possible?
I'm very familiar with imaginary work. It's when you sit in a comfortable chair thinking about the things you have to do  8)
https://en.wikipedia.org/wiki/Virtual_work

Bear in mind that the concept of imaginary quantities in electrical theory is merely a construct that makes the calculations easier to use and understand. It actually indicates a phase shift; nothing more.
« Last Edit: 08/05/2015 04:59 PM by deltaMass »

Offline aero

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SeeShells has indicated that fields generated using 3 antennas located around the frustum would be interesting. The first natural thought is to separate the antennas by 120 degrees but on second thought, that seems as though it would mix the x and y Electric components. Further, the Magnetic component might not be well excited using a lateral antenna, perhaps a longitudinal antenna would be preferable for the Magnetic component.

In an attempt to shed light on this conumdrum, I made 6 resonance runs with Harminv, one with the antenna excited by each of the 6 EM field components. I did not change or move the antenna in any way. It is still the same antenna and cavity as used in generating the data showing the "Orbital Angular Momentum" posted yesterday. (Note: I don't know that that run showed Orbital Angular Momentum, but it looks like it to me.)

This is the Harminv results showing the Q and the amplitude of the detected resonance for each component.

TE components   Ex               Ey               Hz
    Q             31,402           3,358,973           11,631
    |amp|   0.1187663886   0.3789006804   0.0618615679

TM components     Ez           Hx               Hy
    Q            (62,063,123)   65,881,511        (94,789)
    |amp|   0.232817953       0.3178146164   0.0868050483

I see from this table that the antenna location/orientation results in strong excitement of the TM mode, but the TE mode is not strongly excited by this antenna with only the Ey field component causing strong resonance. Using 3 different antenna locations/orientations is a natural consideration and it should be straight forward to locate the antennas individually to achieve strong resonance for each individual field component. A difficulty arises in emplimentation.

Each individual antenna will generate it's own field components at the common frequency but it is desired, even necessary that the fields positively reinforce the resonant field in the cavity. That means they must be in phase with the resonant fields. Does that mean that the E field component antennas need to be separated by one wavelength and the H field antenna removed from both by in interger multiple of 1/4 wavelength? No - 1/4, 1-1/4, 2-1/4 ... wavelengths?

Ideally I could run all possible reasonable combinations but the bash shell software needed is beyound me and although this model completes quickly when running resonance, it still takes time to manually do the parameterization. I need a really good guess at the antenna locations to start with.
Retired, working interesting problems

Offline rfmwguy

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@deltamass and others - question O-the-Day

CoE and CoM and coriolis effect at luminal velocities (boom!)

Struggling with my theory a bit. Pour water (uncompressable) into a funnel (part of a frustum) and the Z axis velocities at the top (big end) exceed Z axis velocities at the bottom (small end). Right? (in flow and out flow equate)

If wrong, what is the relative speed of the water molecules to each other?

Now, substitute fixed speed photons in place of water molecules in a funnel (frustum). Something has to give.

What gives for CoE and CoM?

p.s. Don't tell me a wormhole opens up ;^)

Offline CraigPichach

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Hmm, good question (though velocities will be larger at the smaller end as opposed to the larger end) - i.e. incompressible so Volume Flow 1 = Volume Flow 2 and Velocity = Volume Flow / Area. So Velocity1 x Area1 = Velocity 2 x Area 2. Quick check with units m3/s x 1/m2 = m/s. So if Velocity and Volume Flow are the same for photons... (hmm, are photons as mass "incompressible"???). This is for a contained incompressible fluid however, which usually light is not.

Reminds me of Joule-Thomson effect - you take a gas, don't allow heat transfer and throttle it (i.e. drop the pressure and allow it to expand). It's an adiabatic system so the temperature of the gas drops basically to keep that equation equaling zero.. in some cases to cyrogenic temperatures. I see it everyday, I get why they have to, but still don't get physically how the vibration of all those atoms adjust.

Now as RF are the photons acting as a "contained fluid" and velocity is locked? If so, even if compressible, there is still conservation of mass in that case where mass = volume x density so your "photon density as mass" could adjust - and does this impact the "quantum vacuum"??. Or does that create "photon as fluid pressure on the vacuum" (negative mass)? Note that Eagleworks seems convinced that magnetohydrodynamics are in play so ironically I think you are going down the path I think they are on.

That being said, I think someone should do a real experiment an order of magnitude above background to verify this phenomena.



@deltamass and others - question O-the-Day

CoE and CoM and coriolis effect at luminal velocities (boom!)

Struggling with my theory a bit. Pour water (uncompressable) into a funnel (part of a frustum) and the Z axis velocities at the top (big end) exceed Z axis velocities at the bottom (small end). Right? (in flow and out flow equate)

If wrong, what is the relative speed of the water molecules to each other?

Now, substitute fixed speed photons in place of water molecules in a funnel (frustum). Something has to give.

What gives for CoE and CoM?

p.s. Don't tell me a wormhole opens up ;^)
« Last Edit: 08/05/2015 06:03 PM by CraigPichach »

Offline jmossman

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During the cordless and totally self contained rotary table EMDrive experiments, the following data will be monitored, data logged and streamed live.

Force generated - calculated
Angular velocity - measured
Angular acceleration - calculated & measured
Forward Rf power - measured
Reflected Rf power - measured
VSWR - calculated
Frequency - measured
Rf amp power consumed - measured
Internal frustum pressure - measured
End plate, side wall and ambient temperature - measured

Any comments on something else to monitor?
Time
Date
Local Magnetic Field
Apx location
Temperature
Humidity
A compass close by to view
Vibration
Digital Stop Watch
Heavy Power Devices locally ie: Transformers
Any High Voltage Power Lines
Turn off Any Fluorescent Lights or if needed screen in Faraday cage (transformer inside)

About all I can think of after the first sip cup of coffee.

Shell
...
Filming both end plates with an IR camera to show mode shapes?

Voltage feeding the RF amp?  (may already be part of your V*I "Rf amp power consumed")

Battery voltage?
« Last Edit: 08/05/2015 05:54 PM by jmossman »

Offline rfmwguy

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Hmm, good question (though velocities will be larger at the smaller end as opposed to the larger end) - i.e. incompressible so Volume Flow 1 = Volume Flow 2 and Velocity = Volume Flow / Area. So Velocity1 x Area1 = Velocity 2 x Area 2. Quick check with units m3/s x 1/m2 = m/s. So if Velocity and Volume Flow are the same for photons... (hmm, are photons as mass "incompressible"???).

Reminds me of Joule-Thomson effect - you take a gas, don't allow heat transfer and throttle it (i.e. drop the pressure and allow it to expand). It's an adiabatic system so the temperature of the gas drops basically to keep that equation equaling zero.. in some cases to cyrogenic temperatures. I see it everyday, I get why they have to, but still don't get physically how the vibration of all those atoms adjust.

@deltamass and others - question O-the-Day

CoE and CoM and coriolis effect at luminal velocities (boom!)

Struggling with my theory a bit. Pour water (uncompressable) into a funnel (part of a frustum) and the Z axis velocities at the top (big end) exceed Z axis velocities at the bottom (small end). Right? (in flow and out flow equate)

If wrong, what is the relative speed of the water molecules to each other?

Now, substitute fixed speed photons in place of water molecules in a funnel (frustum). Something has to give.

What gives for CoE and CoM?

p.s. Don't tell me a wormhole opens up ;^)
This is where my theory is trying to go, but brain cells put up a brick wall. Cannot compress photons, velocity is fixed (or is it?), mass is variable according to einstein as C is approached...(tilt)!

So, I ponder...thanks for your post.

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