Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1803468 times)

Offline StrongGR


Are you saying that given the reasoning and calculations depicted in your paper. After doing some numerical analysis on the equations for the frustum configuration you are left with a really small effect orders of magnitude below that which has been reported so far by Shawyer, Yang, Cannae, EW, and jullian (The ukranian replicator, I am sure I probably butchered his name.)?

Just want to make sure I am understanding what your saying.

Yes, general relativity accounts for really a small part of the effect if this would be confirmed.
« Last Edit: 05/26/2015 05:12 PM by StrongGR »

Offline aero

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I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.

So how would that work? Would the gas be ionized in a preferred direction such that a gas molecule accelerated in the positive direction (to pick a coordinate direction) would be less massive (by an electron or a few electrons) than the gas returning. The ionized gas reaches the base plate and on contact is deionized by accepting electrons from the metal then the less strongly ionized (neutralized) gas is accelerated (drifts) back to the other end finding the region within the cavity where ionization occurs with electrons given up to the cavity walls or other end. The cycle repeats.

The ionized gas molecule would be slightly less massive than the neutral molecule but due to much greater charge, would move at a much higher speed, hence impart more momentum to the end plate than would the slightly more massive (heavier) but much slower neutral molecule.  The electrons added to the base plate don't actually circulate back with momentum because it is the charge that travels at near light speed, the electrons in the cavity metal oscilate with low or zero average momentum.

Paul March reported that at one time Eagleworks did use a dielectric gasket separating the big end (maybe both ends) from the frustum body but they replaced the gasket with a metal/metal contact seal. I wonder why. Perhaps without electrical continuity it didn't work.

Edit Add: I just described a recirculating ion gun didn't I? How hot is this antenna anyway?
« Last Edit: 05/26/2015 06:26 PM by aero »
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Offline TheTraveller

Isn't there some conference set for mid-September where we might hear more one way or the other on this topic? Unfortunately for the life of me I've forgotten what it's called but, I'm sure Mr Shawyer did a presentation at it in 2013 if that helps identify it.

Shawyer did say he would be presenting a peer reviewed paper in 2015,  detailing the superconducting work he has done with other companies.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline tchernik

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Japan has used a Maser to beam a scale model rocket up a few feet:

Microwave powered rocket ascends without fuel

http://www.technologyreview.com/view/420700/microwave-powered-rocket-ascends-without-fuel/

That looks like a beamed energy thermal rocket.

They would most definitely work, are very scalable, but alas, not propellentless.

Offline phaseshift

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Slowly making progress on this model.  This is all generated mathematically (well most of it), some is fudged a little until I have the appropriate math worked out.  This model is actually Shawyer's higher fidelity thruster with a tuning cylinder.  It also has no o-rings which I still am going back and forth on - I'm about to put them back in I think. This model does have spherical end plates.

I've just started working on the tuning mechanism. While its true that the RF can be tuned I want to do it initially by sizing the cavity and be able to see the affects of pulling the small plate in and out a small amount. 

I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Edit: This is not Shawyer's higher fidely thruster - selected the wrong drop down from the menu - they look very similar
« Last Edit: 05/26/2015 07:06 PM by phaseshift »
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline TheTraveller

Quote from: phaseshift
I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Make it a zip file, then attach.

Suggest you show the excitation mode (TM or TE) and m,n type as Df will change due to altering cut off wavelength.
« Last Edit: 05/26/2015 06:40 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 phaseshift

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Quote from: phaseshift
I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Make it a zip file, then attach.

Suggest you show the excitation mode (TM or TE) and m,n type as Df will change due to altering cut off wavelength.

Yes, that's getting adding 'shortly' - I have to labor through the math - not exactly like riding a bike, but it's slowly coming back to me :)
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline phaseshift

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Make it a zip file, then attach.


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

Offline tchernik

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Hello again esteemed NSF forum posters.

I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I would like to know if there is some kind of laundry list of experiments someone with an Emdrive could do to help clarify the nature of this phenomenon and validate more its existence, and eventually help others get better results. And if not, maybe add it to the Wiki.

For example, some people say the Q factor is relevant for getting more thrust, but others disagree. Maybe experiment no. 1 should be raise the Q factor somehow and see the impact on thrust at the same power input? maybe eventually do it with superconducting cavities, supposed to raise Q factor by a lot?

Some say higher power is the key. So experiment no 2 should be measuring thrust a different input power regimes?

Others say air or a dielectric inside the cavity may be relevant to having thrust or not (or much more or less). So experiment no 3. should be running it with and without a dielectric inside with a same power input, and experiment no 4. running it with and without air (e.g. with pure Nitrogen) in the cavity, maybe even with a vacuum cavity?

And so on. It seems there are many theories hinting at potential factors and explanations, and it would be great if people with so many potential explanations gave hints to the experimentalists what to do, in order to do some triage of potential causes or factors impacting thrust (and help determine if there is any anomalous thrust or not).
« Last Edit: 05/26/2015 10:40 PM by tchernik »

Offline phaseshift

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Hello again esteemed NFS forum posters.

I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I would like to know if there is some kind of laundry list of experiments someone with an Emdrive could do to help clarify the nature of this phenomenon and validate more its existence, and eventually help others get better results. And if not, maybe add it to the Wiki.

For example, some people say the Q factor is relevant for getting more thrust, but others disagree. Maybe experiment no. 1 should be raise the Q factor somehow and see the impact on thrust at the same power input? maybe eventually do it with superconducting cavities, supposed to raise Q factor by a lot?

Some say higher power is the key. So experiment no 2 should be measuring thrust a different input power regimes?

Others say air or a dielectric inside the cavity may be relevant to having thrust or not (or much more or less). So experiment no 3. should be running it with and without a dielectric inside with a same power input, and experiment no 4. running it with and without air (e.g. with pure Nitrogen) in the cavity, maybe even with a vacuum cavity?

And so on. It seems there are many theories hinting at potential factors and explanations, and it would be great if people with so many potential explanations gave hints to the experimentalists what to do, in order to do some triage of potential causes or factors impacting thrust (and help determine if there is any anomalous thrust or not).

I also think that environmental factors should be measured at the time of the experiments, temperature, humidity, barometric pressure, phase of the moon (lol), etc. would like a laundry list of those.
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline Star One

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Isn't there some conference set for mid-September where we might hear more one way or the other on this topic? Unfortunately for the life of me I've forgotten what it's called but, I'm sure Mr Shawyer did a presentation at it in 2013 if that helps identify it.

Shawyer did say he would be presenting a peer reviewed paper in 2015,  detailing the superconducting work he has done with other companies.

Well that's good to hear. If it's at that conference I hope there will be presentations from other interested parties.
« Last Edit: 05/26/2015 07:21 PM by Star One »

Offline deltaMass

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Based on the different theories listed in the Wiki, which one is thought to have the best predictive ability, based on the data laid out in the same Wiki?

Offline demofsky

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I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.

So how would that work? Would the gas be ionized in a preferred direction such that a gas molecule accelerated in the positive direction (to pick a coordinate direction) would be less massive (by an electron or a few electrons) than the gas returning. The ionized gas reaches the base plate and on contact is deionized by accepting electrons from the metal then the less strongly ionized (neutralized) gas is accelerated (drifts) back to the other end finding the region within the cavity where ionization occurs with electrons given up to the cavity walls or other end. The cycle repeats.

The ionized gas molecule would be slightly less massive than the neutral molecule but due to much greater charge, would move at a much higher speed, hence impart more momentum to the end plate than would the slightly more massive (heavier) but much slower neutral molecule.  The electrons added to the base plate don't actually circulate back with momentum because it is the charge that travels at near light speed, the electrons in the cavity metal oscilate with low or zero average momentum.

Paul March reported that at one time Eagleworks did use a dielectric gasket separating the big end (maybe both ends) from the frustum body but they replaced the gasket with a metal/metal contact seal. I wonder why. Perhaps without electrical continuity it didn't work.

Edit Add: I just described a recirculating ion gun didn't I? How hot is this antenna anyway?

I personally prefer to look at this as a recirculating ionic wind tunnel.    :P

Either way, zapping nice heavy ions back and forth really helps with the orders of magnitude of the effect, whatever it might be.  What might be happening is that the ions are standing in for us as nice heavy virtual protons to help out with the practical application of the various theoretical frameworks emerging here and elsewhere.  Hm. 


Offline deltaMass

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Gas model.
Pressure inside is everywhere the same. So the total force on the small end is less than that on the big end.


The trick is to notice what happens on the sidewalls!

So heavy ions or light atoms or light - it's all the same.
Standard physics says "no net thrust"

Offline aero

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Gas model.
Pressure inside is everywhere the same. So the total force on the small end is less than that on the big end.


The trick is to notice what happens on the sidewalls!

So heavy ions or light atoms or light - it's all the same.
Standard physics says "no net thrust"

No no no - That's only true for static pressure case where P = Ps = constant. In the dynamic case, Pt = Ps + Pd

In the recirculating ion gun cavity model there is dynamic pressure and ram pressure to consider. The largest momentum component (and velocity) would be moving toward the small end, hence along the central axis with lesser momentum component along the frustum walls. Similar mass with some extra electrons but spread across a much larger area so lower velocity.

Look at the dynamic pressure components. Higher velocity stream along the central axis so total pressure, static plus dynamic presses the small end while the same thing happens at the large end. The difference being that dynamic pressure is 1/2 rho V2 in both cases. But much smaller velocity gives much smaller dynamic pressure

From Prof. Yang's translated paper -
Quote
regardless whether charge particles are presented within the volume, the surface electromagnetic force can change the momentum within the volume V.

As I understand it, the change in momentum results from the change in velocity of the particles (for the case with particles present) so there is more involved here than just static, dynamic or total pressure.
« Last Edit: 05/26/2015 08:39 PM by aero »
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Offline deltaMass

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I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.

Offline Rodal

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...I have to admit I am less thrilled about the theoretical explanations than about the experimental reports...
We had discussed (towards the end of thread 2) whether to split the tread, but the overwhelming response was that "United we stand and divided we fall," that it is to the benefit of everybody to keep theoretical, experimental and strongly skeptical discussions under the same thread so that we can arrive at a common understanding of the truth behind this, which is dictated by that inflexible ruler, Mother Nature   :)


« Last Edit: 05/26/2015 08:41 PM by Rodal »

Offline frobnicat

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I wonder if "sealed" and "gas tight" are truly synonymous here. After all, there is an RF connector (at least)

I'll ask Shawyer.

It wouldn't matter unless the test was done in a vacuum.  In ambient, the partial vapor pressure of the water wouldn't change (well...not much...heating MIGHT drive the moisture out somewhat).  This is a potential explanation of why there is a difference between tests at ambient pressure and those in a vacuum (if the device is NOT a pressure vessel).  Is it possible to get to White as well to ask about their test unit?

We know from at least one post of Paul March (in thread 2, but I don't have the link at hand, sorry) that the frustum at Eagleworks is not gas tight, as it was said to be venting to vacuum (when operated in vacuum). I don't recall more details about specifics, total area of gaps between inside and outside for instance. The venting seems not designed (no venting ports) but rather the consequence of no specific measure to make the frustum airtight. Also there was discussion of the gap between cone and end plates, motivated by simulations of near field with MEEP. Maybe Aero you recall the possible range for such gap ?

Offline Rodal

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I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 

Just like the great job you did addressing energy conservation.

It seems to me that she also needs to take into account directional attenuation  in order to get a non-zero Poynting vector.

If you have a chance to look at her equations, I'll for one, would appreciate knowing what you think about them   :)
« Last Edit: 05/26/2015 08:37 PM by Rodal »

Offline aero

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Quote
Maybe Aero you recall the possible range for such gap ?
Paul suggested to me that the gap could not be larger than 0.002 inches, and likely much smaller due to the frequency and tightness of the bolts holding the frustum to the end plates.
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