Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1803790 times)

Offline frobnicat

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Let's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions.  It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum.  Nature has its own laws.

You yourself said that a CoE issue is a CoM issue and reciprocally (if relativity is to hold). So how can you say that CoE is a red herring and straw man argument, when as far as em drive effect apparent impossibility is concerned, apparent CoE breaking fits the bill as much as apparent CoM breaking ?

(10mN corrected to 10N, thanks, wanted to leave margin against uncertainties, don't change the argument, could be ever so slightly above photon rocket, .2N for 50W for instance, already apparently breaking CoE...)

What I wrote  is that assuming constant acceleration at constant power is a straw man argument.

I also add to that now that assuming a limiting velocity as a constraint is another straw man argument.

Perhaps I should add a list of unwarranted assumptions to the EM Drive wiki ?

Efficiency of vehicles is governed by thermodynamics, and not just based on kinematics or dynamics or frame-indifference.

I still don't get your inclusion of second law in that.

Could you please explain what is your proposed phenomenology of not constant acceleration at constant power ? a(t) = function( power(t) + what else ) ? Have you a precise idea or is it just a hint ? Since you seem to discard completely a(t) = cst * power(t), do you see any consistent alternative ?

Offline SeeShells

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Let's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions.  It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum.

Somebody already started a poll on people's beliefs on the EM Drive.

While I use Bayesian Statistical Analysis (on things like the stock market, that are driven by people's beliefs) to make a living, this emphasis on what people in this forum believe regarding something governed by Nature escapes me.

Nature has its own laws.
You're right Mother Nature has her own laws and some of them like Quantum Mechanics seem to violate them. When I first read about quantum entanglement I said no, no way can one particle effect another particle that is entangled instantaneously, but it happens. We have tried to comprehend these laws as best we can and as faulted as we are many a time we are simply dead wrong.

Our views on violation's of any of natures is naive thinking don't get huffy and close your mind because an equation points to a violation of CoM, CoE or thermodynamics. Keep the door open, keep an open mind just because a road sign says One Way doesn't mean you can't drive down it and look at the sights. Even Einstein called entanglement spooky action, but accepted the data. I see very spooky actions in the EMdrive. We need more data from real tests, solid data, data we can plug in our mathematical models to see if they agree.

Ok, off the soap box and on to having fun in my shop, the iron is hot and I want to melt something.

Offline frobnicat

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I still don't get your inclusion of second law in that.

Could you please explain what is your proposed phenomenology of not constant acceleration at constant power ? a(t) = function( power(t) + what else ) ? Have you a precise idea or is it just a hint ? Since you seem to discard completely a(t) = cst * power(t), do you see any consistent alternative ?
You can't break the first law.  Agreed. 

You cannot break the 2nd law either (most of the time at least  ;)  )

All you prove by assuming unwarranted assumptions (constant acceleration at constant power) is that, Ahem  :), your assumption (constant acceleration at constant power) was unwarranted.

If you want to prove more, you can go for example, next to the 2nd Law, that should impose further restrictions on efficiency.

And constant thrust at constant velocity at constant power ? Is it unwarranted also ?

We have from Eagleworks reports 50N at constant velocity for 50W, for 40s.

Hypothesis 1 : this is from forces that are spurious, in the sense : acting between moving assembly and local grounded agents (vacuum chamber walls, earth magnetic field, earth g ...). I guess you think this is a viable hypothesis. This would make the device not only commercially un-useful for space flight but the whole concept as utterly irrelevant to any space propulsion application (even a marginal one) and irrelevant on this forum. We might still learn interesting other aspects...

Hypothesis 2 : this is a "real" propulsive component. Should it dislike acceleration, it can be made to run in the same conditions as reported results, at constant velocity (with appropriate mounting on actuators on an accelerating spacecraft body) on 40s intervals and still be of propulsive use (and have apparent CoE breaking as consequence). If it's acting 40s then what fundamental limit would prevent it to act for 400s ? for 40000s ? Assuming this can't act more than 40s continuous, what duration would it have to be "resting" before it's switched on again ? Or can it do only a 40s run only once in its all life, needing a complete remelt and rebuild, or fresh copper maybe  ? Does it need a certain amount of energy to be "bootable" to a 40s run again ? Where exactly your second law fits in this picture ?

In my picture of a perpetuum movement of the first kind from constant thrust at constant velocity at constant power, second principle is respected as inefficiencies bleed (and radiate in space) waste heat at every step. Only if averaged thrust/power ratio don't exceed 1/c this schemes becomes impossible, from 1st law alone. Second law only brings a small margin above 1/c before we are in trouble, and with 50N at constant velocity for 50W, for 40s, we are in trouble.
« Last Edit: 06/06/2015 06:16 PM by frobnicat »

Offline Rodal

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...Where exactly your second law fits in this picture ?

In my picture of a perpetuum movement of the first kind from constant thrust at constant velocity at constant power, second principle is respected as inefficiencies bleed (and radiate in space) waste heat at every step. Only if averaged thrust/power ratio don't exceed 1/c this schemes becomes impossible, from 1st law alone. Second law only brings a small margin above 1/c before we are in trouble, and with 50N at constant velocity for 50W, for 40s, we are in trouble.
Well, this will turn a lot of people off  ;), because it gets technical, by I see the 2nd law useful in restricting constitutive equations.  Through the Clauss-Duhem inequality.  It would address the constitutive equations issues brought up by WarpTech.

See this, for example, from Prof. David Steigmann, Prof at Berkeley:

https://www.researchgate.net/publication/245381814_On_the_Formulation_of_Balance_Laws_for_Electromagnetic_Continua

I have not seen this having been done for the Quantum Vacuum yet (not just White's theory, but any theory, including chirality, for example, etc.)

I have not seen it done by Prof. Wooodward's group either, yet.
« Last Edit: 06/06/2015 06:53 PM by Rodal »

Offline WarpTech

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Rather than try to keep up with this conversation on preferred frames and CoM, CoE violations. Here is the solution. I've updated both of my recent papers and the solution to this Energy Paradox problem is simply Einstein's Equivalence Principle, and once you read it you will understand that it makes no difference if it is conventional propulsion, a photon rocket or an EM Drive, CoE and CoM are NOT violated.

Please read it and add them to the Wiki so this paradox can go away and the straw man can go back to scaring crows. (ha ha ha)

Regarding the preferred frame. Is the gravitational potential you are standing in now a preferred frame, relative to one at a different altitude? Granted, I prefer sea level with a cocktail myself.  8)

Thank you and enjoy!

Todd



Offline Tetrakis

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Rather than try to keep up with this conversation on preferred frames and CoM, CoE violations. Here is the solution. I've updated both of my recent papers and the solution to this Energy Paradox problem is simply Einstein's Equivalence Principle, and once you read it you will understand that it makes no difference if it is conventional propulsion, a photon rocket or an EM Drive, CoE and CoM are NOT violated.

Please read it and add them to the Wiki so this paradox can go away and the straw man can go back to scaring crows. (ha ha ha)

Regarding the preferred frame. Is the gravitational potential you are standing in now a preferred frame, relative to one at a different altitude? Granted, I prefer sea level with a cocktail myself.  8)

Thank you and enjoy!

Todd

Can you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.

Offline WarpTech

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Can you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.

Frame invariance, meaning "Lorentz Invariance" is not applicable in an accelerated reference fame. It is not even applicable when the acceleration value is small. In order for frame invariance to be applied correctly, it must be comparing two inertial reference frames where acceleration = 0. It does not equal 0  in a gravitational field or in a ship with a constant thrust-to-power ratio.
« Last Edit: 06/06/2015 08:04 PM by WarpTech »

Offline rfmwguy

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Interesting 2012 article on the Pioneer Spacecraft...seems its been decelerating for several years. Its called the Pioneer Anomaly "The effect is something like when you're driving a car and the photons from your headlights are pushing you backward" Seems classical science types are all happy with the explanation: http://www.space.com/16648-pioneer-anomaly-spacecraft-mystery-solved.html

wiki link: http://en.wikipedia.org/wiki/Pioneer_anomaly

This dove-tails into a discussion of Anisotropy: http://en.wikipedia.org/wiki/Anisotropy see the "Physics" paragraph. Mechanically, the Frustum does have the potential (pun intended) of this property with the large and small diameters.

« Last Edit: 06/06/2015 08:30 PM by rfmwguy »

Offline deltaMass

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Can you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.

Frame invariance, meaning "Lorentz Invariance" is not applicable in an accelerated reference fame. It is not even applicable when the acceleration value is small. In order for frame invariance to be applied correctly, it must be comparing two inertial reference frames where acceleration = 0. It does not equal 0  in a gravitational field or in a ship with a constant thrust-to-power ratio.
I'm a little behind the curve at the moment. Have to digest Higgins and these new papers of yours.

Re. acceleration and SR, it's not so bad. The trick is to utilise an "instantaneous comoving inertial frame", which of course is continually refreshed. In SR, accelerations transform like gamma3

Offline Rodal

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Can you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.

Frame invariance, meaning "Lorentz Invariance" is not applicable in an accelerated reference fame. It is not even applicable when the acceleration value is small. In order for frame invariance to be applied correctly, it must be comparing two inertial reference frames where acceleration = 0. It does not equal 0  in a gravitational field or in a ship with a constant thrust-to-power ratio.

Not just that, but  "frame-invariant" absolutists are not taking into account that frame-invariance only applies to isotropic constitutive material properties. Frame-invariance does not apply to chiral anisotropy and diverse kinds of anisotropy where there are preferred material frames.  Blindly imposing absolute frame-invariance on the EM Drive is precluding anisotropic explanations based on chirality for example. 

I will add  imposition of frame-invariance aka "assumption of isotropy" to the list of assumptions that are often being made.

It is fine to make assumptions, but they should be stated.  For example, the frame-invariance absolutists, should preface by "assuming isotropy" etc....

van Tiggelen has something to say about it (momentum from the QV).

Having said that, it is not clear to me that anisotropy  (chirality, etc.) is involved here. Even in that case one should be able to distinguish a preferred frame of co-moving, embedded material coordinates, where the 1st and 2nd Law of Thermodynamics, as well as momentum conservation still apply.  (But when there is anisotropy, sometimes there are non-intuitive things that can happen).
« Last Edit: 06/06/2015 09:12 PM by Rodal »

Offline Prunesquallor

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Rather than try to keep up with this conversation on preferred frames and CoM, CoE violations. Here is the solution. I've updated both of my recent papers and the solution to this Energy Paradox problem is simply Einstein's Equivalence Principle, and once you read it you will understand that it makes no difference if it is conventional propulsion, a photon rocket or an EM Drive, CoE and CoM are NOT violated.

Please read it and add them to the Wiki so this paradox can go away and the straw man can go back to scaring crows. (ha ha ha)

Regarding the preferred frame. Is the gravitational potential you are standing in now a preferred frame, relative to one at a different altitude? Granted, I prefer sea level with a cocktail myself.  8)

Thank you and enjoy!

Todd

I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments.
Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?

Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power.

What will happen?
Retired, yet... not

Offline birchoff

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Rather than try to keep up with this conversation on preferred frames and CoM, CoE violations. Here is the solution. I've updated both of my recent papers and the solution to this Energy Paradox problem is simply Einstein's Equivalence Principle, and once you read it you will understand that it makes no difference if it is conventional propulsion, a photon rocket or an EM Drive, CoE and CoM are NOT violated.

Please read it and add them to the Wiki so this paradox can go away and the straw man can go back to scaring crows. (ha ha ha)

Regarding the preferred frame. Is the gravitational potential you are standing in now a preferred frame, relative to one at a different altitude? Granted, I prefer sea level with a cocktail myself.  8)

Thank you and enjoy!

Todd

Quote
Could the EM Drive create an artificial gravitational potential?

Gotta ask, given your analysis so far what would need to occur inside the EmDrive for it to create an artificial gravitational potential?

Offline wallofwolfstreet

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I have a question Todd on your Resolution of the Space-Drive Energy Paradox paper.

It pertains to the following section, so I include it here:


The correct interpretation is such that to exceed the limiting velocity, a higher
input power is required. It is incorrect to assume that because a force is being exerted, the
velocity will continue to accelerate beyond the limit at which the kinetic energy exceeds
the total input energy and the system becomes a perpetual motion machine of the first
kind. [1]

The physics is similar in nature to hovering in a gravitational field, where Special
Relativity does not apply. The Newtonian gravitational potential Φ has units of ( m / s)2,
such that the gradient derivative yields an acceleration vector. It represents the potential
energy per unit mass and may be treated identically to the velocity squared in Newtonian
kinetic energy, v2 = 2E / m.

In order to remain stationary at a given altitude in a gravitational field, a constant
force must be exerted, along with a constant acceleration and a constant input power.
There is no gain in altitude, no increase in the potential energy and no increase in
velocity. Although power and force are being expended constantly. 


Question:  When a conventional machine is hovering in a gravitational field, like a helicopter or a falcon 9, it is expending power constantly to generate a force equal to the force of gravity.  There is no gain in kinetic energy of the machine.  All of the power being expended is transferred to surrounding air in the case of the helicopter or propellant for the falcon 9.  When an EMdrive has reached it's limiting speed, and is expending power with no gain in kinetic energy,where does this power go such that CoE is obeyed?       

Offline WarpTech

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....

I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments.
Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?

Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power.

What will happen?

Assuming identical input power is available, when you detach Stage 2 from Stage 1, it now has half the mass, so it can accelerate up to ~ 2*delta-v.


Offline TheTraveller

Off the shelf, DIY Mini EMDrive case?:

Ebay: "Copper-Shot-Glass-Gift-Present-Shooter-Drinking-Party-Cups-Alcohol-Spirits"

Have bought a few to measure up and using the EMDrive Calculator to see what resonate frequencies and excitation modes it can work with, versus predicted Df and thrust.
« Last Edit: 06/06/2015 10:55 PM by Chris Bergin »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline WarpTech

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...
Could the EM Drive create an artificial gravitational potential?

Gotta ask, given your analysis so far what would need to occur inside the EmDrive for it to create an artificial gravitational potential?

As I've said, over a very narrow bandwidth near the cut-off wavelength, this is exactly what it's doing. The attenuation of the waves is identical to a frequency dependent metric, g_uv, where in this case;

-g_11/g00 = 1 + a^2/k^2, where "a" is attenuation function (Zeng & Fan's Hankel functions) and "k" is the wave number. It has no effect on atoms or lasers, but will strongly affect EM waves with a wavelength in the vicinity of the cut-off.

Todd

Offline WarpTech

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I have a question Todd on your Resolution of the Space-Drive Energy Paradox paper.

It pertains to the following section, so I include it here:


...

In order to remain stationary at a given altitude in a gravitational field, a constant
force must be exerted, along with a constant acceleration and a constant input power.
There is no gain in altitude, no increase in the potential energy and no increase in
velocity. Although power and force are being expended constantly. 


Question:  When a conventional machine is hovering in a gravitational field, like a helicopter or a falcon 9, it is expending power constantly to generate a force equal to the force of gravity.  There is no gain in kinetic energy of the machine.  All of the power being expended is transferred to surrounding air in the case of the helicopter or propellant for the falcon 9.  When an EMdrive has reached it's limiting speed, and is expending power with no gain in kinetic energy,where does this power go such that CoE is obeyed?     

It goes into maintaining a state of compressed, time dilated matter, just as in a gravitational field. In order to do so, it is pushing up-hill against a gravity well that is resisting the acceleration. There is constant force on your feet while standing on the ground. Power is being applied by the gravitational field, yet you're not moving or gaining energy. Where is the power going? It is going into maintaining your state of compression.

Therefore, the EM Drive, if it is creating and can maintain a gradient in (P/F)^2, then it it will accelerate until it reaches a gradient in the potential energy per unit mass that exerts an equal and opposite force. At which point, it is the same as standing on the ground just to maintain the relative compression. If you turn off the engine, it will no longer "feel" like an accelerated reference frame. It will become a weightless inertial reference frame, and so the feeling of compression to the floor would disappear.

I guess it would be correct to say, the power goes into maintaining a gravitational field, aka an accelerated reference frame, even though it's not gaining any relative velocity.

Todd

Offline wallofwolfstreet

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....

I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments.
Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?

Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power.

What will happen?

Assuming identical input power is available, when you detach Stage 2 from Stage 1, it now has half the mass, so it can accelerate up to ~ 2*delta-v.

Let's change the question up a bit.  After Stage 1 has been powered for long enough that it's maximum delta-v has been achieved, turn it off.  Don't detach it this time.  Your spaceship, made of the two identical emdrive stages, is now floating through space at delta-v plus whatever initially velocity it had.  Let's say that the spaceship is in deep space, negligible gravity.  In this inertial frame, the spaceship has no way of "knowing" whether it is moving or standing still.  How does Stage 2 "know" it is currently moving at it's limiting velocity, without invoking a preferred frame?  If it is allowed to act as Stage 1 has, than kinetic energy will have gone up 4 times, even though power expended only doubles.   
« Last Edit: 06/06/2015 10:30 PM by wallofwolfstreet »

Offline zen-in

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...

Have bought a few to measure up and using the EMDrive Calculator to see what resonate frequencies and excitation modes it can work with, versus predicted Df and thrust.

It may be a Copper colored glaze on glass so the conductivity would not be very high.   On thread 2 someone mentioned they had a machinist spin a cone for them.   That's a good way to go, especially if they can put a straight section in at the thin end (closed) end.   The only downside is the surface after metal spinning is not very smooth, because of the way the metal gets moved.

Offline WarpTech

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....

I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments.
Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?

Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power.

What will happen?

Assuming identical input power is available, when you detach Stage 2 from Stage 1, it now has half the mass, so it can accelerate up to ~ 2*delta-v.

Let's change the question up a bit.  After Stage 1 has been powered for long enough that it's maximum delta-v has been achieved, turn it off.  Don't detach it this time.  Your spaceship, made of the two identical emdrive stages, is now floating through space at delta-v plus whatever initially velocity it had.  Let's say that the spaceship is in deep space, negligible gravity.  In this inertial frame, the spaceship has no way of "knowing" whether it is moving or standing still.  How does Stage 2 "know" it is currently moving at it's limiting velocity, without invoking a preferred frame? ...

Because, when the engine was running, every sub-atomic particle of matter was accelerated and in dong so, their momentum increased. Relative to where it started from, the wavelength of every matter-wave has been reduced in size and this represents the real stored energy of inertia. Therefore, the matter that was accelerated "knows" it was accelerated because it possesses more inertia than when it started. In this regard, when the engine is turned off, it is equivalent to orbiting at a constant gravitational potential (v^2), in free-fall at a constant velocity, as opposed to hovering at this potential when the engine was running.

Einstein's Equivalence Principle still rocks!  ::)

Todd

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