Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1876525 times)

Offline TheTraveller

.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.

Give me another 6 weeks and I will have plenty of hard numbers for you and everybody else. Test runs will be streamed on YouTube and open to comments and discussion in real time. All data will be displayed in real time, logged and available for anyone to review.

My goal is to draw a line in the sand, stop the doubts and get on with developing a supportive theory from the experimental data.
"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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.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.
This is a better way to frame your question:

What are the conjectured time intervals necessary to

a) store the N*photon energy

and

b) let the N*photon momentum go. ?
« Last Edit: 05/27/2015 09:15 PM by Rodal »

Offline TheTraveller

Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.
...
Great idea to look at convection currents when doing experiments in air.   Either natural convection currents produced by power dissipation at the EM Drive external surfaces or forced convection from heated moist air pressurized in its interior and leaving through gaps.   Something that researchers doing experiments in air can use to validate or nullify experimental explanations.  (Not so much for Quantum Vacuum as those are virtual particle pairs that have an ephemeral life governed by Heisenberg's uncertainty principle)

Shawyer covered that. See the sealed Faraday Cage around the 1st Experimental device. I really don't know why this is still being brought up. It was designed out of his 1st test protocol.

According to Shawyer, the thrust is not being caused by heated air nor radiated thermal energy nor ionic jets nor thermal expansion nor CG movement.
« Last Edit: 05/27/2015 06:26 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 Rodal

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Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.
...
Great idea to look at convection currents when doing experiments in air.   Either natural convection currents produced by power dissipation at the EM Drive external surfaces or forced convection from heated moist air pressurized in its interior and leaving through gaps.   Something that researchers doing experiments in air can use to validate or nullify experimental explanations.  (Not so much for Quantum Vacuum as those are virtual particle pairs that have an ephemeral life governed by Heisenberg's uncertainty principle)

Shawyer covered that. See the sealed Faraday Cage around the 1st Experimental device. I really don't know why this is still being brought up. It was designed out of his 1st test protocol.
I don't see anything there that can effectively eliminate natural and forced convection currents.
Aerodynamics shows that natural convection currents can exist in very confined spaces (thus the narrow gaps necessary for insulating glass panes in double-pane windows, for example).   It takes a very small, narrow gap of air to eliminate convection and favor conduction in air, as natural convection of a gas is always a preferred method of heat transfer than conduction (unless the air gap is very small).

The thrust is not being caused by heated air
I don't recall seeing any analysis proving that statement.  What I recall is @frobnicat posting a good analysis showing that air exhaust was a plausible explanation for the measured thrust.  Thus this possibility still remains open until proven otherwise. 

I am not saying that it has been proven that convection is an explanation for the thrust, or even addressing its Bayesian probability.  Just saying that the post from @cometo indicating how to show air convection currents is indeed a positive, helpful post, for experiments done in air, under ambient conditions.
« Last Edit: 05/27/2015 06:22 PM by Rodal »

Offline TheTraveller

I don't recall seeing any analysis proving that statement.  What I recall is @frobnicat posting a good analysis showing that air exhaust was a plausible explanation for the measured thrust.  Thus this possibility still remains open until proven otherwise. 

I am not saying it is an explanation, but the post indicating how to show air convection currents is indeed a positive post.

We have very little real data and that we do have has been data mined to death. So there is a lot of guesstimation. Shawyer has claimed hot air was controlled for and was not the cause of the thrust measured in his 1st experimental device. He claims 7 UK aerospace companies, microwave engineers and academics vetted the full reports data.

Would be nice to have that report. I'm working to make that happen.

In the Chinese devices, the test device movement is horizontal, so external rising hot air and internal buoyancy effects of heated air should have little effect on horizontal thrust. However CG movement, from thermal expansion could affect measured thrust as the device balances on a lower knife edge.
« Last Edit: 05/27/2015 06:25 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 rfmwguy

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@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.


Offline deltaMass

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@Rodal: The net stored momentum of all cavity photons is zero, almost. There is a contribution from the source.
« Last Edit: 05/27/2015 06:29 PM by deltaMass »

Offline TheTraveller

@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.

You can go to the members page and see all their postings and attachments.

As example for Mulletron:
http://forum.nasaspaceflight.com/index.php?action=profile;area=showposts;u=45378
"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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@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.
As to the benefits of splitting the EM Drive thread, the last time we asked, at the end of the 2nd thread, the common wisdom was that the majority did not want to split the thread.  The argument was made that the benefit of having everybody in the same thread and thus creating synergy was far greater than the drawback of exponential growth of the thread and arguments between posters.

Arguments between posters, as long as they remain polite, and they concentrate on technical matters, are not to be seen as bickering, but on the contrary as a means to arrive at a common truth.  We can all learn from each other.

Division into small groups of people holding the same view, leads to group-think (http://en.wikipedia.org/wiki/Groupthink)


Quote
Group members try to minimize conflict and reach a consensus decision without critical evaluation of alternative viewpoints, by actively suppressing dissenting viewpoints, and by isolating themselves from outside influences.

Loyalty to the group requires individuals to avoid raising controversial issues or alternative solutions, and there is loss of individual creativity, uniqueness and independent thinking. The dysfunctional group dynamics of the "ingroup" produces an "illusion of invulnerability" (an inflated certainty that the right decision has been made). Thus the "ingroup" significantly overrates its own abilities in decision-making, and significantly underrates the abilities of its opponents (the "outgroup"). Furthermore groupthink can produce dehumanizing actions against the "outgroup".

Group-think has terrible consequences for innovation and R&D.  There is all kind of data showing that the most innovative research groups are composed of individuals with very different backgrounds.  It is their differences that fosters innovation.

Think of when we were children trying to figure out the world: how we explored everything and we were not afraid to ask questions.  Most scientists and engineers are the most creative and innovative when they are young.  Same with groups: having different people, and new people joining the forum with different viewpoints is actually a plus, although it may produce some self-questioning of held-beliefs and produce arguments.  Better than being fossilized into a common way of thinking assuming that everything has already been taken into account.


Please check with NSF site administrators, as I am not familiar with the latest rules on creating new threads.  The only thread I introduced at NSF was this 3rd thread as Chris warned that he had to close the 2nd thread because it was too long. :)
« Last Edit: 05/27/2015 07:21 PM by Rodal »

Offline phaseshift

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I am very surprised by those poll results.  Based on those results, where individuals who feel their is propellantless thrust are slightly more numerous than those who claim no thrust, implies that the general consensus places the odds of their being a genuine, previously unknown//non-classical force at about 50% (ignoring all the people who don't have an opinion).

I find that to be an extremely high estimate given everything we have seen so far.  Yes, their have been replications, but this isn't a result that can easily be validated.  Lots of hard to control for confounding factors, and  it's a huge claim being made. 

I would have put the odds at somewhere in the 2-3% range.  Maybe 5% if I was feeling optimistic.  Interesting to learn that the forum overall is leaning to a much greater likelihood.  Just my two cents.


Edit:  Here is the link to the poll:  http://forum.nasaspaceflight.com/index.php?topic=37644.0

Not surprising considering the thread's demographic :)
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.
Maybe a good idea to put the data on the wiki: http://emdrive.echothis.com/Experimental_Results, no?
« Last Edit: 05/27/2015 07:12 PM by bprager »

Offline deltaMass

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I finally  figured out how to make my microwave fly! Give a good solid kick!
But it doesn't fly very far, I think because the cord comes unplugged right away.

If you replicate my experience, be very careful, you could get hurt - I recommend combat boots.
Clearly you didn't put the right gravity warp virtual vacuum plasma magnetochiral floobie dust in it.
« Last Edit: 05/27/2015 07:15 PM by deltaMass »

Offline deltaMass

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@Rodal: The net stored momentum of all cavity photons is zero, almost. There is a contribution from the source.
was using WarpTech's statement << It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.>> to frame the question in terms of the time intervals that he conjectures for these processes to require, in order to address your prior point (does the data show that or not ?)

If the "net stored momentum of all cavity photons is zero, almost" that answers your question: as the time interval for storage is then practically zero, and not visible in the data charts.

You are not going to find "small fractions of a second" time bursts in 20 sec data that does not have that level of time discretization detail.

...For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.
For the purposes of Todd's argument, we should be talking about stored energy and not stored momentum, since he explicitly mentions CoE. I recall calculating the stored energy a ways back to be substantially less than 1 Joule (if this forum had a half-decent search function, I'd quote the exact figure :(). I think it was Q*P/omega, so for EW that's roughly 6,000*85/(2*Pi*1.9e9) = 5e-5 J. Looks about right. How long does the input power take to accumulate that energy? t = 5e-5/85 = 0.5 usec.

I am pointing out that 20 seconds is substantially longer than 0.5 microseconds.

Offline tchernik

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I finally  figured out how to make my microwave fly! Give a good solid kick!
But it doesn't fly very far, I think because the cord comes unplugged right away.

If you replicate my experience, be very careful, you could get hurt - I recommend combat boots.

The best part is that your Microwave propulsion technology proposal is clearly propellentless, but not reactionless.

And we can be reasonably certain it respects both conservation of momentum and energy.  ;D

Offline Rodal

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...For the purposes of Todd's argument, we should be talking about stored energy and not stored momentum, since he explicitly mentions CoE. I recall calculating the stored energy a ways back to be substantially less than 1 Joule (if this forum had a half-decent search function, I'd quote the exact figure :(). I think it was Q*P/omega, so for EW that's roughly 6,000*85/(2*Pi*1.9e9) = 5e-5 J. Looks about right. How long does the input power take to accumulate that energy? t = 5e-5/85 = 0.5 usec.

I am pointing out that 20 seconds is substantially longer than 0.5 microseconds.
Fair enough.  We agree on the possible time interval and that "stored energy" is the correct term to use.  WarpTech will answer for himself, but my interpretation (perhaps wrong ?) of what he was proposing is a series of very short time bursts (~ microseconds) that will not be visible in a 20 second long time chart. 

Therefore we cannot use the time charts to assess whether his model is correct or not.

Microsecond bursts would be  invisible in the time chart, since it does not have that kind of resolution, and I expect that NASA's Eagleworks torsion pendulum dynamics x(t) (being measured) would not show that kind of response to F(t):

m d2x/dt2 + c *dx/dt + K x = F(t)

where x is a rotational degree of freedom around the torsional axis, m is the moment of inertia, c is the damping and K is the torsional stiffness

microsecond bursts would get damped out, and the response governed by the pendulum dynamics. Which is what we see: a response (for NASA Eagleworks) that is governed by the pendulum dynamics, with some small amplitude noise on it (see my Autocorrelations and Power Spectral Density analysis of Eagleworks data earlier in the thread).
« Last Edit: 05/27/2015 08:09 PM by Rodal »

Online WarpTech

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.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.

Maybe my words are so elaborate this time, but all I am saying is a photon rocket has a thrust of,

F = dp/dt = P/c, P is power, p is momentum.

So far, all experiments show a thrust,

F < Q*P/c < Q*dp/dt

So it is not as efficient as a photon rocket of power Q*P. Sorry, I'm at lunch. Don't have time right now to work out a detailed duty cycle expression, but you get the picture.







Offline maciejzi

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Would it be possible to use magnetic forces (e.g. electromagnets) to capture the microwaves in the cavity for a longer period of time?

Maybe instead of extremely high Q cavities it would be easier to use electromagnets around the frustum to keep the microwaves inside and/or direct the microwaves in the required direction and/or slow them down as required?

I mean instead of superconducting frustum, which requires heavy cooling, it may be easier to achieve the required thrust by putting the frustum in electromagnetic trap or even to replace the copper walls with electromagnets and injecting the microwaves in such magnetic box?

Offline KittyMoo

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Would it be possible to use magnetic forces (e.g. electromagnets) to capture the microwaves in the cavity for a longer period of time?

Maybe instead of extremely high Q cavities it would be easier to use electromagnets around the frustum to keep the microwaves inside and/or direct the microwaves in the required direction and/or slow them down as required?

I mean instead of superconducting frustum, which requires heavy cooling, it may be easier to achieve the required thrust by putting the frustum in electromagnetic trap or even to replace the copper walls with electromagnets and injecting the microwaves in such magnetic box?
No

Offline X_RaY

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Hello i am new in this forum. Based on my own simple model(flat end plates) the frequency has to be approximately 2.52GHz.
I hope this is helpfull :)

Hi, can you share your model?

Yes, its an simple libreoffice file. I use this to calculate resonance fequencys of shaped cone cavitys. Some days ago i implemented the trust/frequency things up to 30GHz based on a file of the forum "Shawyer Design Factor Frequency Scanner Version 2014 May 12 B.xls"

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.
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   :)
I tried. The formatting of the equations is execrable, but despite that and after reading all of it, and then realising that she was using Maxwell to produce evidence of an asymmetrical force, I knew the entire paper was wrong. The reason it's wrong is because group velocity is being conflated with phase velocity.

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