Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1873345 times)

Offline Flyby

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What really bothers me in the new Shawyer video are the projections for the future.
Sadly, they kinda eat away his credibility..

Unless he can really show off by standing on a floating platform, powered by his supercooled EMdrive, I'm not prepared to "believe" him because he said so...
I have serious doubts on the needed scalability of the effect (IF it is real) due to the increased thermal effects it will cause.
Assuming there is indeed a measurable force (we're still not 100% sure, although there are intriguing results that point in that direction) it is far from certain that it will ever produce to projected "tons of thrust".

I think one of the first things to test AFTER it has been proven the device works (we're still not past that stage), is to test out whether or not an increased Q has a positive effect on the output forces. It will make all the difference whether we'll have "floating cars" or just micro-thrusters for satellites/solar probes.

With only a few hundred grams of thrust, our lifestyle will not change, but space exploration might...

I was hoping for an explanation on how the thrust force is generated, yet the vagueness of his answer left me perplexed. There is no real argumentation on how CoM is established, except for the confirmation it does.. But, sorry to say, words are easy and cheap...

Also very confusing on having it compare to a rocket engine, saying it isn't a rocket engine, yet use action-reaction to explain the thrust, which is in essence how a rocket engine works... there is an uncomfortable mixing of systems/concepts there. It just isn't a satisfactory explanation for me.

How hard can it be to really show off some of his older outdated test rigs in action? just to convince a larger audience, now his "invention" got the spotlights? Why would you limit yourself to gestures and words only? It's a flawed marketing strategy, certainly when you had such a hard time to convince the scientific community for almost a decade...

Sigh.. kinda disappointing... :'(

ps.
It is strange he almost never looks straight to the interviewer or the camera...feels more like a internal monologue then a communication to persuade others...Needs some media training, for sure.. :)
« Last Edit: 05/24/2015 10:18 AM by Flyby »

Offline Star One

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This may sound harsh but he often seems his own worst enemy when it comes to promoting it.

Offline deltaMass

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He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.

Offline CW

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(...)

ps.
It is strange he almost never looks straight to the interviewer or the camera...feels more like a internal monologue then a communication to persuade others...Needs some media training, for sure.. :)

When I watched the interview, his constant averting his eyes from the interviewer or camera evoked an impression towards me, as a neutral spectator, that he was literally trying to completely escape the subject at hand. I didn't like that at all. Also, quickly diverting the focus towards applications just increased the feeling of something fishy going on. It left me with a feeling of a marketing man saying 'Yes, our rainbows have a bigger pot of gold at their end. It's a 2nd generation gold pot to boot!' .

I think it is very easy to convince the public that Mr. Shawyer's devices in fact do what he claims: Make a demonstration! We don't need your second generation thrusters that are said to work wonders (IIRC 30kN/kW). A couple Newton per kW, that clearly and visibly accelerate a compact test article for some time and in a useful manner, is all that any critic of your devices needs to shut up, Mr. Shawyer. Is it so hard to do? Really?? And please don't start possibly claiming that as per contract with XYZ you cannot reveal such a demonstration. Such a claim, if made, would maybe impress a hamster, but not human adult scientist-level minds. It is not us, who have to convince ourselves, that your device works as claimed. It is your task to convince us by unambiguous demonstration, that it works as claimed.. .
« Last Edit: 05/24/2015 11:48 AM by CW »
Reality is weirder than fiction

Offline StrongGR

He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.

Here it is not a matter on how you sell a product. We are in need of a serious verification of the effect to ascertain it is real. NASA took the step in the right direction but further independent repetitions are strongly needed.

Offline deltaMass

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Well, you are absolutely right. I was responding to the critique of the body language of course.

Online kdhilliard

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I'm pretty sure he is not saying that he has actually felt the thrust with his hand from any of his exiting drives, but instead that were you to build a model with higher thrust you could feel it

From the video you could take it either way. Either he has, or you would, feel a force. What is odd though is how do you get from a reaction-less drive that operates by bouncing microwaves around in a cavity, to something that behaves more like a traditional rocket. How do you make that leap. Perhaps Shawyer found the rocket like behaviour when he built his prototype, has mashed the two together because he is not quite sure what is going on, and has been hand-waving ever since.

Point of terminology - As Shawyer points out, this is not a reactionless drive, rather a propellant less drive.

Paraphrasing Newton's third law, Action = Reaction. Let's don't break that law along with all the others. If reaction = zero, then Action = zero and zero doesn't show on most force measuring devices that I know of.

Zaphod: Yes, his words could be taken either way, but taking everything as a whole I'm confident he did not meant that he (or anyone else) has actually felt this trust from an existing EmDrive.  Otherwise he wouldn't need the elaborate test rigs to demonstrate that he had created something novel.

Aero: Yes, Shawyer do claim that it isn't reactionless and that it obeys Newton's laws, but simply claiming so is not enough when the theory he describes doesn't obey these laws.  He's trying to have it both ways.

Law 3 (action vs. reaction) concerns the interaction of two bodies.  In the case of the EmDrive the bodies are the cavity and the photons which are reflecting back and forth inside it.  Every time a photon is reflected off an end plate, it exerts a force against the end plate and the end plate exerts an equal and opposite force against it.  Shawyer claims that there is a net imbalance of forces in the cavity (contrary to most everyone else's application of Maxwell's laws), but that's fine.  He already has had his action and reaction.  Invoking the third law a second time to declare a new reaction force when there are no new additional bodies interacting the the cavity just doesn't make any sense.

He is welcome to claim that he has invented a repulsor drive which can repel your hand when held in close proximity to an end plate or hover some distance over the ground via some perhaps unexplained interaction with the Earth, but that is not what he has done.  He claims to offer a complete fundamental theory behind the operation of the EmDrive, but this theory is not self-consistent.  What he describes does not obey Newton's laws, no matter how much he says to the contrary.

This isn't much different from how Shawyer states that the device obeys Conservation of Energy because the specific thrust declines with acceleration along the thrust vector such that (T/P) < 1/v, meaning that the power consumed is always larger than the work done T v < P.  But this is not enough because CoE is invariant across all inertial reference frames and Shawyer's construction is not.  If a system obeys CoM, then if it obeys CoE in any one frame it obeys CoE in all frames, but Shawyer's system violates CoM so CoE will be violated in all but one frame.  Shawyer conveniently constructs it so that CoE holds in the reference frame from which the cavity starts accelerating from v=0.

~Kirk

Offline Rodal

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He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.
perhaps not a good idea to generalize in the manner of speaking, particularly when it comes to the reluctance to make eye contact, etc., that maybe individual traits...I wonder what it would be like to listen to famous British engineers like James Watt, George and Robert Stephenson, Charles Babbage, Oliver Heaviside, Sir Frank Whittle, and Sir Christopher Cockerell to name a few... Too bad that we don't have videos of Heaviside as I think he would have been a very interesting one to hear.   Maybe there is some film of Frank Whittle around.


Here is one Brit with great penetrating eyes narrating looking at you right in your eyes and cadence in his voice (@ 1:50) what it was like to work with Whittle

« Last Edit: 05/24/2015 01:01 PM by Rodal »

Offline Flyby

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He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.

I'm not expecting toothpaste or white teethed, tanned faced,  ear to ear smiles... TBH, that would be even less productive then what it is now.

If you've seen some of the interviews with Edward Witten, on string theory, you can clearly see he's not skilled in media training either. That In contrast fe, with Michio Kaku, who's very skilled in using media.
Yet, I'm by far more captivated by E.Witten's interview(s) because it feels so much more authentic and has so much more substantial content.

but, to put things in the correct perspective, it is not my intention to play on his personality. Everybody has his sets of skills and weak points. I do not have anything personal against R.Shawyer. On the contrary. It's just I see it as a missed opportunity : If you know you're not very well in explaining with words, you simply need to show it. Sadly, he did neither...

There would be absolutely no shame into simply saying that he doesn't really know how it works. But evoking theories that can be easily shredded by theoretical physicists does not help his case and that's something, even as an engineer, he should realize.

I doubt it is a pure cultural thing, more of an individual attitude, as i know plenty of engineers that are reasonable and passionate debaters...
however, I used to have a prof in philosophy that had the same characteristics : talking for more then an hour, with his eyes closed and not looking at his audience...     
It's....bizarre...gives you an odd feeling...

I just can not hide my disappointment on the interview.. sorry for that...
With all the raging pro/contra debates i was expecting more for him... my fault probably..
« Last Edit: 05/24/2015 01:19 PM by Flyby »

Offline Flyby

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Concerning the 3rd presentation video.


At 19:23 timeframe, a road map for the EMdrive development is shown.

Does any one have a more readable version of it?
With this low resolution, it's just impossible to make anything out of it...
« Last Edit: 05/24/2015 01:40 PM by Flyby »

Offline Star One

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It would be better if he had just said sorry I don't really know how it works.

Offline Rodal

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Besides the previously discussed facts that Shawyer's theory implies:

1) The Design Factor is calculated as if the EM Drive instead of being a single truncated conical cavity, it is composed of two disjointed separate waveguides, one waveguide having the cut-off frequency of the Big End and the other waveguide having the cut-off frequency of the Small End.

2) Mass of waveguide associated with the Small End is positive, normal mass

3) Mass of waveguide associated with the Big End is negative, exotic mass

4) Total mass of EM Drive cavity is zero.



We have another exotic thing going on when we calculate the Work.  Let's remember from our first course in Physics that the Work of a force is the product of the force vector and the displacement:

Work = Force * displacement

ForceDirection (+) & DisplacementDirection (+)   then Work (+)
ForceDirection (-) & DisplacementDirection (-)   then Work (+)

ForceDirection (+) & DisplacementDirection (-)   then Work (-)
ForceDirection (-) & DisplacementDirection (+)   then Work (-)




the usual case: POSITIVE WORK

When a force acts on a moving body and the direction of the force and the direction of the displacement coincide, then the transfer of energy from the body which exerts the force to the body which is moved is positive. 

A positive value of the Work corresponds to the transmission of energy from the acting body to the body which is moved.  This is the usual case in the overwhelming number of physical cases: the stretching a spring under a tensile force, the compressing of a spring under a compressive force , the displacement of a weight sliding with friction on a surface under the action of a force, etc.



the unusual case: NEGATIVE WORK

When the directions of the force and of the displacement are opposite then conversely, the energy is transmitted from the body which is moved, to the body exerting the force.  In this case, the Work of the force is negative.

Please observe that what Shawyer's theory proposes is that the Thrust Force (directed towards the Big End) is in the opposite direction to the movement of the EM Drive (which is described as taking place towards the Small End).  Hence Shawyer's theory is describing negative Work being done by the EM Drive when it moves towards the Small End.



5) Shawyer's theory (since Shawyer's "Thrust force" exerted by the  microwave photons is in the opposite direction to the movement of the cavity) implies that energy is being transmitted from the copper cavity (the body being moved) to the photons in the cavity (which are exerting the Thrust Force). 

This is the direct opposite of what most people have been discussing in this thread (envisioning the photon's energy as being transmitted to the copper cavity).  Shawyer's theory implies the complete opposite: that energy from the copper cavity is transmitted to the photons  inside the cavity.


Shawyer theory:

motion of Metal Cavity  <====> opposite direction to Thrust force exerted by microwave photons

hence: Negative Work being done

Energy from Metal Cavity (being moved) ==> is transmitted to ==> microwave photons inside cavity (exerting force)



Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.
« Last Edit: 05/24/2015 02:49 PM by Rodal »

Offline SeeShells

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I'm going out on a limb here and I'm going to try to keep it simple as we have many readers that get lost in heavy equations (me too) and collage phd physics. I've been reading so many papers these last few weeks and watching youtube videos trying to get up to speed and polish up an education that is 40 something years old and it's daunting.

Our universe's laws of CoE and CoM, quarks, gluons and gravity... etc, etc. all are ordered, they are clean and fit like a beautiful picture of how our universe works. We're even unraveling what happens around a black hole and even leading to wonderful ideas of what happens in one. The reason all the theories work is because they lay their foundations in solid harmonic (working together) coupled, fundamental forces. I feel comfort that the world is ordered and locked together and things work the way they are supposed to. That's the engineer in me.

I'll tell you where I'm coming from and where I'm going with this thought. I read this weeks ago shortly after I joined this group and it will not go away. I keep coming back to this perception I have of how this self assembled universe works and the one thing that is outside of it all.
Wikipedia~ Our universe started from a dense soup of quark gluon mix and self assembled the only way it could according to those basic forces. The electromagnetic, strong, and weak interactions associate with elementary particles, whose behaviors are modeled in quantum mechanics (QM). For predictive success with QM's probabilistic outcomes, particle physics conventionally models QM events across a field set to special relativity, altogether relativistic quantum field theory (QFT).[4] Force particles, called gauge bosons—force carriers or messenger particles of underlying fields—interact with matter particles, called fermions. Everyday matter is atoms, composed of three fermion types: up-quarks and down-quarks constituting, as well as electrons orbiting, the atom's nucleus. Atoms interact, form molecules, and manifest further properties through electromagnetic interactions among their electrons absorbing and emitting photons, the electromagnetic field's force carrier, which if unimpeded traverse potentially infinite distance. Electromagnetism's QFT is quantum electrodynamics (QED).~
That's beautiful (Shell)

The one "force" that ignored all this mix of neatly assembled pieces and parts and the fundamental forces had to play its game was and is space time.

Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.

It fits and as strange as it sounds when all else is eliminated and believe me great thinkers and beautiful minds have beat this can and kicked it up down and around and I've read most. 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

Offline Notsosureofit

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Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.

You only have to prove it instantaneously.  Then it will hold in the frame of reference of the cavity due to GR.  Inertial frames won't do it, they aren't accelerating.

I think I can state this differently;

All you need for a mathematical "proof" of a thought experiment in this case is to show that a finite force remains in the limit as the work done by the cavity motion goes to zero in some inertial frame. (ie the cavity is accelerating)

"showing it" is the interesting part....
 

Offline zaphod_vi

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Quote
Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.

Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.

Online WarpTech

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[...]

The cutoff and guide wavelengths are different for TE and TM modes and what m,n values you use. This affects Df.

I adopted my spreadsheet to handle both TE01 and TM01 modes so a 1 cell binary change flips between them.

Length is then determined by numerically intergating 1,000 diameter changes between the end plates and working out the averaged guide wavelength to give 1/2 wave resonance. Then the driving Rf can be a harmonic of the averaged guide wavelength. Length is then adjusted so the external Rf harmonic is the same as the selected Rf wavelength.

Is there any particular combination of length, radii and frequency, that would make the energy difference between the TM01 and TM11, or other mode very large? If there is a way to maximize this gap in energy, it will maximize the energy stored in TM01, I think...

Offline phaseshift

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Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.


Until proven otherwise I'll point to Lisa Randall's gravity brane and the hypothetical finite length 4th spacial dimension.  Inflate that dimension using RF energy and the strength of gravity is diminished.  The Universe itself inflated  3 spatial dimensions in the inflationary period, so there is a mechanism.

Upcoming experiments at CERN this summer are looking to confirm/disprove predictions from her theory. As I understand these are the first predictions to come from string theory that are testable.
« Last Edit: 05/24/2015 03:27 PM by phaseshift »
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Offline Notsosureofit

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Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.


Until proven otherwise I'll point to Lisa Randall's gravity brane and the hypothetical 4th spacial dimension.  Inflate that dimension using RF energy and the strength of gravity is diminished.  The Universe itself inflated  3 spatial dimensions in the inflationary period, so there is a mechanism.

Upcoming experiments at CERN this summer are looking to confirm/disprove predictions from her theory. As I understand these are the first predictions to come from string theory that are testable.

Yes, that could give a gradient and the cavity could "fall" toward the small end.

All you need is for the cosmological constant to be a function of the radiation field strength (like in the early universe ?)
« Last Edit: 05/24/2015 03:52 PM by Notsosureofit »

Offline Rodal

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Streamed live on Apr 25, 2013
Special guest theorists Lisa Randall from Harvard University and Raman Sundrum from University of Maryland, who join CERN physicists to look at how the LHC experiments are investigating extra dimensions.
« Last Edit: 05/24/2015 04:00 PM by Rodal »

Offline TheTraveller

[...]

The cutoff and guide wavelengths are different for TE and TM modes and what m,n values you use. This affects Df.

I adopted my spreadsheet to handle both TE01 and TM01 modes so a 1 cell binary change flips between them.

Length is then determined by numerically intergating 1,000 diameter changes between the end plates and working out the averaged guide wavelength to give 1/2 wave resonance. Then the driving Rf can be a harmonic of the averaged guide wavelength. Length is then adjusted so the external Rf harmonic is the same as the selected Rf wavelength.

Is there any particular combination of length, radii and frequency, that would make the energy difference between the TM01 and TM11, or other mode very large? If there is a way to maximize this gap in energy, it will maximize the energy stored in TM01, I think...

Shawyer says you only need to excite the frustum in TM mode and have end plate to end plate resonance at the effective 1/2 guide wavelength and the external Rf to be a harmonic of that effective guide wavelength.

End result is all 4 physical dimensions of the frustum, big & small diameter, end plate spacing and external Rf all affect each other. To get good thrust at a set frequency needs the 3 physical dimensions to be manulipulated in an interactive process that properly models how they interact.

I also feel doing a frequency sweep to look for resonance mush be done slowly as it takes time for a high Q frustum to react to the external Rf and fully fill the cavity. Sweep too fast and you may miss the high Q sweet spots.

The sweep must excite the cavity in TM mode. Putting a stub antenna through the frustum side wall will not, as far as I understand the process, excite TM mode. It will just excite TE mode. It seems you need to put the probe in the middle of one end to excite TM mode. But I'm not yet a microwave engineer, so there may be other ways to excite TM mode.

Any comments on how to excite TM mode, in a frustum, with a coax feed would be most welcome.
« Last Edit: 05/24/2015 04:16 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
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