Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1876207 times)

Offline Rodal

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...
When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.

Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration.
what matters is what she means:  her words: "net EM ... directs towards the minor end plate". The microwave EM is inside not outside, hence no ambiguity
« Last Edit: 05/24/2015 07:07 PM by Rodal »

Offline phaseshift

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"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline Blaine

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This is a conversation on reedit about using two different metals for a DIY experiment for EM Drive.  I butted in but the headline and description read as fallows:

The EmDrive has been ridiculed by other scientists because Sawyer does not take into account of the sidewalls into his calculations. They say that the microwaves also push down on the sidewalls so no net positive force in any direction is created.

However, I think I have an idea that may improve the net force of the EmDrive. Microwaves bounce around inside the EmDrive before that energy is converted to heat. What if the sidewalls were made of a metal that converted the energy to heat more rapidly than the flat-ends? For example, the sidewalls could be made off copper and the flatends could be made of tin. Tin heats up more slowly than copper so the microwaves would bounce off the tin generating a force. When the microwaves hit the copper sidewalls some of that force is converted to heat quicker than the tin, and therefore there will less force on the sidewalls as compared to the tin.

So, if the EmDrive is multicompound with tin ends and copper sides then a bigger force will be generated



You have a few misconceptions about what is going on. The argument about 'pushing' on the walls involves momentum exchange which should be conserved so there is no way net force should be apparent from the outside. This is what the controversy is about.

The EM waves don't really 'bounce around'. If the chamber is resonating the waves are standing waves and would appear to not move if you could see them.

The heat comes from the resistive loss (low Q) of the chamber. This somewhat different from the momentum exchange and has to do with energy loss rather than momentum. The difference is on the quantum level, but they are two different things. In fact reducing the heat by making the chamber super conducting is expected to increase the thrust, which is the opposite of your idea. This is because we're talking about two different things (friction or heat vs. momentum).

Force from thermal expansion is very minimal and is internal to the junction between the two metals, there should really be no apparent external force or movement due to thermal heating or differencing in heating coefficients.
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[–]BlaineMiller 1 point 4 minutes ago*

Ah, but look at it from a chemistry point of view. Couldn't the different materials on the side wall also produce microwave radiation? Because if what if we were talking about thermal agitation of two different metals?

Thermal agitation is one source of microwaves at the heart of atoms and molecules. Any action that these atoms have at higher temperatures above absolute zero can cause them to absorb and emit radiation, including microwaves. Maybe the thermal motion of the atoms in the copper is somehow absorbing enough radiation to make it possible to ignore that there would be zero net force. In other words, the sides of this asymmetrical cavity would not feel any force. All the extra radiation would be inside the copper atoms because of thermal motion of atoms because of thermal agitation and microwave absorption properties of the end metal.
« Last Edit: 05/24/2015 07:13 PM by Blaine »
Weird Science!

Offline deltaMass

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http://www.gizmag.com/scientists-create-real-protons-from-virtual-ones/20689/

Huh, that's interesting.
People are playing around with "electron mirrors" these days with a view to reflecting gammas. The inertia of such a contraption is exceedingly low and, being charged, is highly amenable to being vibrated. I wonder if there's a way to do a direct dynamic Casimir experiment with this technique.

Offline SeeShells

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...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)
Ahhh the Quantum Vacuum, the QV. If there wasn't so much evidence that it exists as appearing and disappearing particles and forces from somewhere out of the planck levels of space and possible links into another dimension of space time, I'd think QV is a Genie in the bottle.
Reading about the QV http://en.wikipedia.org/wiki/Vacuum_state
What is that time period I need to "give it back"? a femtosecond, 1 week, a couple years, the forecast age of the universe? I'm not sure if it is a set time as we see it. And what if I warped, just a little and just enough spacetime with an EM field, would that have an effect of the borrowed time and during that time I had it couldn't I just strip of a little something extra before I gave it back?
My head is feeling a little mushy and I think I need some hot tub time with something cold.
To all, thanks for putting up with me and my crackpot ideas of our world.

Online WarpTech

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Quote from: Rodal
----

Her conclusion and final paper attached.

Very interesting.  Thus we see here that Prof. Yang, far from imitating Shawyer, states a completely different conclusion: that the "measured net EM thrust" is directed towards the small end (towards the "minor end plate"), (the complete opposite of what Shawyer states).  She also states that this thrust direction (towards the small end) agrees with her theoretical prediction of thrust direction.

AND her theory predicts the thrust level per power input.  All without needing new  physics.

"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd

Offline deltaMass

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If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?
« Last Edit: 05/24/2015 07:28 PM by deltaMass »

Offline Rodal

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...Would appreciate a look at this lecture chap 7.

Quote from: Germain Rousseaux
The ‘‘Galilean’’ equations used by van Tiggelen et al.
[1] in bianisotropic media as well as Feigel [2] in dielectric
media to prove the existence of the so-called ‘‘Feigel effect’’
are a mixing of these two separate Galilean transformation
laws. Hence, I suggest that the effects predicted by
van Tiggelen et al. and Feigel are not observable within the
realm of Galilean Physics as they are based on wrong hypotheses.
...’ Now, to be honest, the
authors try in their reply to formulate a Lorentz-covariant
theory in order to show that ‘‘zero-point momentum is
allowed in a fully Lorentz-invariant model.’’ I would leave
this point to others for discussion but stand still on the
impossibility to describe the Feigel–van Tiggelen effect in
a Galilean way.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248901
« Last Edit: 05/24/2015 07:34 PM by Rodal »

Offline deltaMass

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http://www.gizmag.com/scientists-create-real-protons-from-virtual-ones/20689/

Huh, that's interesting.
People are playing around with "electron mirrors" these days with a view to reflecting gammas. The inertia of such a contraption is exceedingly low and, being charged, is highly amenable to being vibrated. I wonder if there's a way to do a direct dynamic Casimir experiment with this technique.
Another approach is to use a nanotube fixed at one end only. The free end will achieve pretty high velocities. But the news is not good, even from state-of-the-art, which is 10 nm length and 100 GHz frequency for goodness sake. That's still only 6 Km/s at the tip.

Offline Rodal

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...
"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd

Yeap, it's kind of funny that we are looking at Prof. Yang's this late in the game.  After all she achieved much higher reported thrust than Shawyer. I think the reason is that Yang does not give the dimensions of her EM Drive.  We naturally concentrated on NASA first.  Also Shawyer because he gave some dimensions (the big diameter of the Exp and the Demo).

It is evident that Prof. Yang's theory is not Shawyer's theory.
« Last Edit: 05/24/2015 07:42 PM by Rodal »

Offline TheTraveller

...
"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd

Yeap, it's kind of funny that we are looking at Prof. Yang's this late in the game.  After all she achieved much higher reported thrust than Shawyer. I think the reason is that Yang does not give the dimensions of her EM Drive.  We naturally concentrated on NASA first.  Also Shawyer because he gave some dimensions (the big diameter of the Exp and the Demo).

It is evident that Prof. Yang's theory is not Shawyer's theory.

That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline Rodal

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...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well,let's forget all the differences between Yang's approach from Shawyer's, using waveguide modes like TM01 (she is using FEA instead based on standing waves), cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Also I don't understand the point you make about predictions.  Prof Yang uses standard FEM analysis based on Maxwell's equations, identical to COMSOL formulation to predict the modes.  Completely different from Shawyer
« Last Edit: 05/24/2015 09:38 PM by Rodal »

Online dustinthewind

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... Wonderfully the one explanation that is left and it's likely to be the one... spacetime.

Thanks all and question it, pull it out and kick it around like a EM can.
Shell

That is the only way at the moment I see how we can violate conservation of momentum with out using propellant is by using information delay over space and time.  Normally the universe appears to conserve these forces (and charge) given enough time.  Once we start modulating information faster than the universe can keep up with it (over space and time) then we might be able to tip the balance so to speak. 

Offline Mulletron

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...Would appreciate a look at this lecture chap 7.

Quote from: Germain Rousseaux
The ‘‘Galilean’’ equations used by van Tiggelen et al.
[1] in bianisotropic media as well as Feigel [2] in dielectric
media to prove the existence of the so-called ‘‘Feigel effect’’
are a mixing of these two separate Galilean transformation
laws. Hence, I suggest that the effects predicted by
van Tiggelen et al. and Feigel are not observable within the
realm of Galilean Physics as they are based on wrong hypotheses.
...’ Now, to be honest, the
authors try in their reply to formulate a Lorentz-covariant
theory in order to show that ‘‘zero-point momentum is
allowed in a fully Lorentz-invariant model.’’ I would leave
this point to others for discussion but stand still on the
impossibility to describe the Feigel–van Tiggelen effect in
a Galilean way.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248901

We all know that Feigel was falsified. What you are quoting is greater than 7 years old and was responded to by another letter * which you conveniently left out. Your amateur attempts at misdirection, rather than academic rebuttal won't go unnoticed. Try harder Doctor. I kindly ask you to excuse yourself from discussion, as you are of no help.

* http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248902

Finally from here:
Quote
Second, the final result
obtained by Feigel for the Casimir momentum density, ∼ ~ R χnr
EMk3dk, seems to lack
a reference frame since this equation is not Lorentz or even Galilean invariant [23].

http://arxiv.org/abs/1404.5990v2

 (free open reference) this is published


« Last Edit: 05/24/2015 08:08 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline TheTraveller

...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well, I will refrain from reengaging on the fact that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using TM01, cut off length, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Please don't  put words in my mouth. I never said the Yang & Shawyers theories were the same. I said both theories claimed to be able to predicted the observed thrust. I also stated both theory approaches were different.

How do I know for sure the predicted thrust is the measured thrust? I don't. But then I'm just an engineer that builds stuff on assumption the models I'm using produce close  to reality results. My excel spreadsheet can't yet do that but every day it gets closer to that goal.

You see I'm not really that interested in the theory other than what it teaches me about how the 4 variables interact.
« Last Edit: 05/24/2015 08:08 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline deltaMass

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This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

Offline Rodal

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...
We all know that Feigel was falsified. What you are quoting is greater than 7 years old and was responded to by another letter * which you conveniently left out. Your amateur attempts at misdirection, rather than academic rebuttal won't go unnoticed. Try harder Doctor. I kindly ask you to excuse yourself from discussion, as you are of no help.
...
Wow.  What a kind response to somebody answering your "...Would appreciate a look at this lecture chap 7."

Offline TheTraveller

This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

The test program I  plan to run will remove ALL doubt that the EMDrive generates real propellantless thrust without needing a space test.

One of my goals is to be able to hold the EMDrive & while switching it on and off, to be able to FEEL the thrust.
« Last Edit: 05/24/2015 08:18 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline deltaMass

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http://www.eagleyard.com/uploads/tx_tdoproductstorage/EYP-TPA-0808-02000-4006-CMT04-0000.pdf

is a nice little asymmetric cavity device just itching to get into space.
But 50 mW in gets you 2 Watts out?
Heh. Forget cavities  8)

Offline deltaMass

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This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

I fully agree.  I think that the space test should be in a controlled course, to also eliminate doubt from anomalies.
Removing doubt is readily achieved by running two identical devices side by side, and only switching on one of them.

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