### Author Topic: EM Drive Developments - related to space flight applications - Thread 8  (Read 1130442 times)

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #920 on: 09/24/2016 03:08 PM »
...

On the ship A = F/M rules. The energy / work required to be done on the constant mass of the ship to effect velocity change never varies. The ship doesn't care what some other frame calculates as the necessary energy to cause velocity change.

If only the ship cares, why does Shawyer speaks about increase of Kinetic Energy. In the ship referential, Kinetic energy is zero...

Why will some external frame alter the work needed to be done on the ship's mass by the EmDrive altering A= F/M? The work needed to be done on the ship's mass, to alter velocity, is constant, independent of any external frame.

This is almost like the twin paradox where only the local frame is important and frame to frame revelance is variable.
It Is Time For The EmDrive To Come Out Of The Shadows

#### tleach

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #921 on: 09/24/2016 03:21 PM »

...

The Earth's frame only matters if an inbound ship needs to match velocity.

However the work needed to be done on the ship's mass to alter the relative velocity to 0, in the ship's frame, stays constant and that is the only effect that is important.

You have to chose one reference frame. "alter the relative velocity to 0, in the ship's frame," if you chose the ship's frame the velocity is always zero and there is no relative velocity.  That would require a second frame.   What you should do is to consider the frame when the ship is at rest; ie: before any acceleration occurs.   Then calculate the final kinetic energy added after the acceleration has ended wrt to this rest frame.   For any reactionless drive the kinetic energy will eventually become larger than the energy used to accelerate the spacecraft.   This is the CoE conundrum all reactionless drives have.  Using 2 reference frames incorrectly as you have done  just introduces another error.  However the equations will never balance with this error so you still have the CoE conundrum.

I added the bolding. Hope you don't mind.

Please correct me if I am wrong, but shouldn't a distinction be made is between reactionless and propellantless. Several of the theories on the table are propellantless, but NOT reactionless. Woodward's MET theory interacts with all mass in the universe, pushing and pulling it's way across the skein using a rapidly moving, minutely varying mass. White's QVPT theory interacts with, and uses as "virtual propellant" the virtual particles of the Quantum Vacuum, making it somewhat akin to both a traditional ion drive and a magnetohydrodynamic drive (like the submarine drive in the Hunt for Red October).

I haven't followed Shawyer's theory as closely as the others, but I did watch one of the videos that Traveller posted awhile back, which Roger narrated and which seemed to me to detail a form of direct momentum transfer from the photons into the frustum. From the CoE perspective, this theory seems to me to be the most suspect. Though, if it works, I think it might satisfy Conservation of Momentum (someone with more physics training than I would have to explain why or why not), which I find an intriguing result worth further study in and of itself. And, this may sound a little crazy, but it is entirely possible in my mind that he could be holding something back and/or intentionally (possibly at the behest of certain organizations) spreading disinformation.
« Last Edit: 09/24/2016 03:53 PM by tleach »
T. Thor Leach

#### TheTraveller

##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #922 on: 09/24/2016 03:23 PM »

...

The Earth's frame only matters if an inbound ship needs to match velocity.

However the work needed to be done on the ship's mass to alter the relative velocity to 0, in the ship's frame, stays constant and that is the only effect that is important.

You have to chose one reference frame. "alter the relative velocity to 0, in the ship's frame," if you chose the ship's frame the velocity is always zero and there is no relative velocity.  If you use the ship's frame of reference you are expending energy and not seeing any increase in the kinetic energy.   What you should do is to consider the frame when the ship is at rest; ie: before any acceleration occurs.   Then calculate the final kinetic energy added after the acceleration has ended wrt to this rest frame.   For any reactionless drive the kinetic energy will eventually become larger than the energy used to accelerate the spacecraft.   This is the CoE conundrum all reactionless drives have.  Using the wrong reference frame  just introduces another error.  The equations will never balance with this error so you still have the CoE conundrum and sometimes in the opposite sense.

There is no error when only the ship's frame is considered.  In that frame A = F/M rules and a constant amount of work on the ship's mass results in a constant acceleration and velocity change.

A EmDrive powered ship, desiring to match a destination velocity, needs only to engage a known amount of work on the ship's mass to effect zero relative velocity.

External KE frames are not involved. Only relative velocity differences between the ship and destination are important and those velocity differences relate to the necessary work needed to be done on the ship's mass to effect the desired velocity change.
It Is Time For The EmDrive To Come Out Of The Shadows

#### tleach

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #923 on: 09/24/2016 03:33 PM »
The basic conservation laws are some of the strongest laws we know of governing the actions of systems and particles in our universe and are not thrown out the window when considering the actions of EM propulsion. They don't negate the data we have seen regarding the drives. They need to be used as a guide within the framework of physics in what maybe happening.

Shell recently stated, in no uncertain terms, that the conservation laws are not "thrown out the window when considering the actions of EM propulsion," which to me suggests that she and most of the attendees of the recent workshop feel that there is no violation taking place in the measurement results to date. So, rather than arguing about how it could never work because it violates CoE, maybe we should be trying to brainstorm possible interactions that would allow us to think about the EM drive as operating via a reaction of some sort.

It's easy to shoot down ideas. It's a little more difficult to come up with new ones. I know it's cliché, but we have to think outside of the box here (and yes, I am familiar with the 9 dot puzzle and was able to solve it without help).
« Last Edit: 09/24/2016 03:52 PM by tleach »
T. Thor Leach

#### Gilbertdrive

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #924 on: 09/24/2016 03:59 PM »
...

On the ship A = F/M rules. The energy / work required to be done on the constant mass of the ship to effect velocity change never varies. The ship doesn't care what some other frame calculates as the necessary energy to cause velocity change.

If only the ship cares, why does Shawyer speaks about increase of Kinetic Energy. In the ship referential, Kinetic energy is zero...

Why will some external frame alter the work needed to be done on the ship's mass by the EmDrive altering A= F/M? The work needed to be done on the ship's mass, to alter velocity, is constant, independent of any external frame.

This is almost like the twin paradox where only the local frame is important and frame to frame revelance is variable.

So, your answer means that Shawyer was wrong about citing the increase of Kinetic Energy, and the fact that Q was decreasing when the speed and the Kinetic energy was increasing ? Have I correctly understood ?

Also, it was not question of altering A=F/M. It was question of a decreasing acceleration AND decreasing force. Still A=F/M.
« Last Edit: 09/25/2016 09:55 AM by Gilbertdrive »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #925 on: 09/24/2016 04:20 PM »
A number of recent posts are addressing violation of conservation of momentum and violation of conservation of energy again. The posts have been addressing the propellant-less drive as it would be a closed-system and ignore any interaction with external fields If one would address a gravity assist maneuver with similar arguments, one would arrive at the obviously incorrect conclusion that there is a huge violation of conservation of energy and momentum, as the spaceship involved in a sling shot maneuver apparently gains  velocity out of nothing.

Obviously to properly consider conservation of mass and energy for a gravity assist maneuver, the spacecraft's effects on the planet must also be taken into consideration. The linear momentum gained by the spaceship is equal in magnitude to that lost by the planet, so the spacecraft gains velocity and the planet loses velocity.  The planet's enormous mass compared to the spacecraft makes the resulting change in the planet's speed negligibly small.
« Last Edit: 09/25/2016 04:16 AM by Rodal »

#### wicoe

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #926 on: 09/24/2016 04:20 PM »
If I look the total Kinetic Energy of the system rocket + propellant, from an earth reference Frame, CoE will always be satisfied. In the earth point of view, the rocket has stolen Kinetic Energy to it's propellant, and there is no paradox.

Good explanation...

This is also generally true for a photon rocket - in the Earth ref frame, the rocket gains more and more kinetic energy after emitting each photon as it accelerates, but it has to lose a bit of its mass with each photon (which is being converted into the energy of the photon), which offsets this difference.  In other words, the mass lost by the rocket plays the role of the propellant - it was moving with the rocket before a boost (and contributing to its kinetic energy), and then it gets converted into the energy of the photons.  I hope I got this right...

I would think that if EmDrive does produce thrust, there is an mechanism to be discovered by which it loses a bit of its mass as it accelerates and emits the lost energy into space in some form or another (minus the difference needed to compensate for the kinetic energy loss equivalent to that of a propellant).

#### wicoe

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #927 on: 09/24/2016 04:26 PM »
A number of recent posts are addressing violation of conservation of momentum and violation of conservation of energy again.  The posts have been addressing the propellant-less drive as it would be a closed-system and ignore any interaction with external fields  If one would address a gravity assist maneuver with similar arguments, one would arrive at the obviously incorrect conclusion that there is a huge violation of conservation of energy and momentum, as the spaceship involved in a sling shot maneuver apparently gains  velocity out of nothing.  Obviously to properly consider conservation of mass and energy for a gravity assist maneuver, the spacecraft's effects on the planet must also be taken into consideration. The linear momentum gained by the spaceship is equal in magnitude to that lost by the planet, so the spacecraft gains velocity and the planet loses velocity.  The planet's enormous mass compared to the spacecraft makes the resulting change in the planet's speed negligibly small.

Thanks for this clarification!  I would just like to point out that a gravity assist maneuver would not work in interstellar space (or would have a much smaller effect), while EmDrive is presumed to produce acceleration that does not depend on its position in the universe.  Or am I missing something?

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #928 on: 09/24/2016 04:41 PM »
A number of recent posts are addressing violation of conservation of momentum and violation of conservation of energy again.  The posts have been addressing the propellant-less drive as it would be a closed-system and ignore any interaction with external fields  If one would address a gravity assist maneuver with similar arguments, one would arrive at the obviously incorrect conclusion that there is a huge violation of conservation of energy and momentum, as the spaceship involved in a sling shot maneuver apparently gains  velocity out of nothing.  Obviously to properly consider conservation of mass and energy for a gravity assist maneuver, the spacecraft's effects on the planet must also be taken into consideration. The linear momentum gained by the spaceship is equal in magnitude to that lost by the planet, so the spacecraft gains velocity and the planet loses velocity.  The planet's enormous mass compared to the spacecraft makes the resulting change in the planet's speed negligibly small.

Thanks for this clarification!  I would just like to point out that a gravity assist maneuver would not work in interstellar space (or would have a much smaller effect), while EmDrive is presumed to produce acceleration that does not depend on its position in the universe.  Or am I missing something?

Consider, for example, the variable inertia effect of Mach/Sciama/Woodward, which is based on General Relativity.  Under this theory, the  inertial Mach Effect is due to gravitational effects from the rest of the universe's "external shell" (Sciama stated that instantaneous inertial forces in all accelerating objects are produced by a primordial gravity-based inertial radiative field created by distant cosmic matter and propagating both forwards and backwards in time at light speed). Therefore it should work in interstellar space as well.  It should work wherever there is inertia.  Also, such considerations flow naturally from Hoyle Narlikar's (HN) gravitational theory. (*)

______________________

(*) Hoyle was well known to insist on a steady-state universe, and he insisted in including the creation field to make the universe steady. If you remove the creation field (or C-field) from the original Hoyle Narlikar theory, the theory is no longer steady state and agrees with WMAP data.

J. V. Narlikar; N. C. Rana (1983). "Cosmic microwave background spectrum in the Hoyle-Narlikar cosmology". Physics Letters A. 99 (2-3): 75–76. Bibcode:1983PhLA...99...75N. doi:10.1016/0375-9601(83)90927-1.

http://repository.iucaa.in:8080/jspui/bitstream/11007/1590/1/130A_1983.pdf

J.V. Narlikar; R.G. Vishwakarma; Amir Hajian; Tarun Souradeep; G. Burbidge; F. Hoyle (2002). "Inhomogeneities in the Microwave Background Radiation interpreted within the framework of the Quasi-Steady State Cosmology". Astrophysical Journal. 585: 1–11. arXiv:astro-ph/0211036. Bibcode:2003ApJ...585....1N. doi:10.1086/345928.

http://arxiv.org/pdf/astro-ph/0211036.pdf

Jayant V. Narlikar, Geoffrey Burbidgeii, R.G. Vishwakarmaiii , (2008) Cosmology and Cosmogony in a Cyclic Universe Journal of Astrophysics and Astronomy 28(2-3) · January 2008
http://arxiv.org/pdf/0801.2965.pdf
« Last Edit: 09/24/2016 09:11 PM by Rodal »

#### tchernik

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #929 on: 09/24/2016 05:03 PM »
Welcome back doc.

Without you and the other knowledgeable posters here, I'm afraid we would be stuck in 1st year pre-grad physics.

#### Chrochne

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #930 on: 09/24/2016 05:16 PM »
Off topic - http://www.nasa.gov/press-release/nasa-to-hold-media-call-on-evidence-of-surprising-activity-on-europa - NASA calls on conference about the Europa moon on 26th. I presume it will be some interesting news. - Its not aliens just to make that clear

"Astronomers will present results from a unique Europa observing campaign that resulted in surprising evidence of activity that may be related to the presence of a subsurface ocean on Europa"

Lets hope it will support a reason to go there. Europa is my personal favorite in our solar system .

Edit: Link fix
« Last Edit: 09/24/2016 05:22 PM by Chrochne »

#### Bob012345

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #931 on: 09/24/2016 05:32 PM »
...
In the ship's frame, the only one which matters, the energy needed to alter velocity in relation to some desired destination is always the same as the ship's mass does not alter. Well not so much as it matters.
All inertial (constant velocity) frames matter, because physics is the same in all inertial frames. This is the fundamental principle of relativity. If you want to jump between frames, then you have to start being careful with transformations, and generally you can't compare energy between frames. Conservation of energy as normally discussed requires you to be talking about a single inertial reference frame. Being in the accelerating frame of the ship requires you to account for non-inertial effects, just like how the Coriolis effect appears if you are in a rotating frame.

BTW Jim Woodward makes a good comment:
http://ssi.org/epi/Over-Unity_Argument_&_Mach_Effect_Thrusters.pdf

Quote
We routinely hear a criticism of METs based upon an argument that claims: if a
MET is operated at constant power input for a sufficiently long time, it will acquire
enough kinetic energy to exceed the total input energy of operation. Assuming this
argument to be correct, critcs assert that METs violate energy conservation as the ratio of
the acquired kinetic energy to total input energy exceeds “unity.”

Contrary to this “over-unity” assumption, this argument is based on flawed
physics and, consequently, wrong. The fact that the argument applies to all simple
mechanical systems (in addition to METs) should have alerted critics to their mistake.
But it didn’t.

So, a dumb idea that should have been quickly buried is still with us. The
purpose of this essay is to carry out a long overdue burial.

I hadn't researched Woodward's theories too thoroughly before, but I had the impression he was a general competent physicist, who was poking for (unlikely) loopholes in general relativity. After reading that paper I no longer have that impression.

After performing a step of just using the transitive property of equality (if a = b and b = c, then a = c), he says:
Quote
Now we have done something stupid and wrong.
It is possible he is referring to the first step in that sequence, where the figure of merit is defined, but that figure of merit comes straight out of theories such as Shawyer's. If that is wrong then the theory that it comes from must be wrong.

he then remarks:
Quote
But this is the mathematics of those who make the “over unity” energy conservation violation argument about the operation of METs.  The real question here is how could anyone, having done this
calculation or its equivalent, think that they had made a profound discovery about anything?

Simple, the step with defining the figure of merit only applies to METs and the like. Making a single assumption when every other step is valid, and ending up in a contradiction is a common way to disprove the assumption. That is what is done here, but Woodward tries to twist this inside out.

The last paragraph of the paper attempts to show the "correct" way of doing this. As part of that he says:
Quote
We know that, starting from t= 0, if we let the integration interval t get very large, the work equation integral will first equal and then exceed the energy calculated by the figure of merit equation.  So we require that t be sufficiently small that this obvious violation of energy conservation does not happen.
He then tries to get around this limit by continuously jumping into the current rest frame of the device. This causes him to be comparing energy between reference frames which is not valid as Bob012345 has pointed out.

The only thing this paper has destroyed for me is the thought that Woodward has any credibility. Unless this paper is some kind of bad joke, or test to see who can find them flaws in it.

The figure of merit itself is not a mistake, it's how people use it to prove a constant force basically does not cause a constant acceleration which is implicit in the criticisms. As I understand Woodward's comments, he's saying one can think of that supposed break even limit as an interval. After that interval, reset or re-guage the problem. Think of a rocket doing a long series of small burns. One ends up with a series of frames, in each energy was not violated but it's a simple undeniable fact of nature that the devices velocity in the last frame is the linear sum of all the frames yet the kinetic energy is different in each frame and far exceeds the sum of input energies in the last frame. But it's not a paradox at all. It's just how nature works and has always been built into classical mechanics.  Woodward's argument is reasonable.

Also, note what he does with the work energy theorem. In every frame, force times distance equals the change in kinetic energy, no energy issues here. Notice how the distance grows with time squared, and one can reconfigure to so it's the same as velocity squared. The work grows as velocity squared as does kinetic energy! That's why it works. There is no paradox in reality. Accept it, it's natures gift.

P.S. If someone still insists it can't work because 'momentum isn't conserved' assume it is, and assume however it is, the ship is just borrowing additional kinetic energy from the 'exhaust' of the universe just as it is in a rocket.

#### Star One

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #932 on: 09/24/2016 05:44 PM »
Welcome back doc.

Without you and the other knowledgeable posters here, I'm afraid we would be stuck in 1st year pre-grad physics.

Seconded good to see you back Doctor Rodal.

#### Bob012345

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #933 on: 09/24/2016 05:52 PM »
Each delta v requires the same burn, not more to account for the fact that future fuel is more effective. The reason we don't see more paradoxes with rockets is that they require so much mass that they run out before that point would be reached and they are so very inefficient so most kinetic energy is wasted.

Also, I don't consider the energy issue a paradox if you use the work-energy theorem. It's the mechanical power times the time that always equates to the kinetic energy change in every observer frame. So there is no paradox. There is just a mixing of energy from different frames that confuses people.

I think I have the right solution for this paradox that completes the answer that Meberbs did.

I shall first formulate the paradox a very clear way.

For classical rockets, unlike a car pushing against a road, the Delta V is the same for each burn.
So, in the earth reference frame, the faster the rocket is, the more Kinetic Energy gained, for the same amount of energy spent.
So, at a certain speed, the rocket gains more Kinetic Energy in the earth reference frame that the energy it has spent.

My solution of the paradox is.

Yes, it is true that in earth referential the rocket gains more Kinetic Energy that it has spent. But the rocket is not alone. The propellant that was expulsed at the opposite direction has now less Kinetic Energy in a earth reference frame. And the faster the rocket was, the more Kinetic Energy it has lost. It compensates the fact that the ship has gained more Kinetic Energy.

If I look the total Kinetic Energy of the system rocket + propellant, from an earth reference Frame, CoE will always be satisfied. In the earth point of view, the rocket has stolen Kinetic Energy to it's propellant, and there is no paradox.

In fact several messages already explicited that, but maybe another formulation can help. Tellmeagain and Meberbs have already made very good explanations.

Everything you said about the rocket is true, however, if you let the rocket burn long enough (unfortunately, you can't because of practical mass limits), even accounting the exhaust energy balance, you would run into the same problem as with the EmDrive.

Regarding the car  for constant power input, acceleration is constant up to a point, then decreases because losses are proportional to velocity. If you could re-guage at the turning point, as Woodward suggests his device can in space, it would remain accelerating.

#### meberbs

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #934 on: 09/24/2016 06:37 PM »
The figure of merit itself is not a mistake, it's how people use it to prove a constant force basically does not cause a constant acceleration which is implicit in the criticisms.
If it is not a mistake then CoE is broken. Denying this is pointless.

As I understand Woodward's comments, he's saying one can think of that supposed break even limit as an interval. After that interval, reset or re-guage the problem. Think of a rocket doing a long series of small burns. One ends up with a series of frames, in each energy was not violated but it's a simple undeniable fact of nature that the devices velocity in the last frame is the linear sum of all the frames yet the kinetic energy is different in each frame and far exceeds the sum of input energies in the last frame. But it's not a paradox at all. It's just how nature works and has always been built into classical mechanics.  Woodward's argument is reasonable.
No it is not reasonable. There is no physical thing that changes about the device after it has been running x seconds. Changing the reference frames and comparing the energy across them is something you already recognized that you can't do; have you forgotten? You don't get to start doing it yourself now that you find it convenient. His argument just ignores the problem that would be obvious if you just did it right and stuck to a single frame.

P.S. If someone still insists it can't work because 'momentum isn't conserved' assume it is, and assume however it is, the ship is just borrowing additional kinetic energy from the 'exhaust' of the universe just as it is in a rocket.
The argument isn't that it can't work because momentum is not conserved, the argument is that certain theories (Shawyer's) are wrong because they don't allow momentum or energy to be conserved.
Everything you said about the rocket is true, however, if you let the rocket burn long enough (unfortunately, you can't because of practical mass limits), even accounting the exhaust energy balance, you would run into the same problem as with the EmDrive.
The rocket doesn't have the problem exactly because it stops working when it runs out of fuel to borrow energy from. Any rocket you can imagine, even the most efficient possible (matter-antimatter reactor with a laser exhaust) will not result in any paradox, energy will always be perfectly balanced. Yet for the proposed explanations of the EMDrive, where it does not have exhaust of any form including a medium to push against, it is easy to find examples that break CoE.

#### zen-in

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #935 on: 09/24/2016 09:20 PM »

There is no error when only the ship's frame is considered.  In that frame A = F/M rules and a constant amount of work on the ship's mass results in a constant acceleration and velocity change.

A EmDrive powered ship, desiring to match a destination velocity, needs only to engage a known amount of work on the ship's mass to effect zero relative velocity.

External KE frames are not involved. Only relative velocity differences between the ship and destination are important and those velocity differences relate to the necessary work needed to be done on the ship's mass to effect the desired velocity change.

You have a mistaken understanding of the concept of frames of reference.   Considering the hypothetical case where you are inside a space capsule that is travelling at 10,000 km/Hr directly away from the Sun.   If you had no instruments that would tell you what your speed was wrt to the Sun, or even a window to look out of, you would not know if you were stationary wrt to the Sun or moving.   You would have the spacecraft reference frame.  If the space capsule was being accelerated you would not know if the force you were experiencing was gravity or due to an acceleration because you would have no means of measuring the change in velocity.   The velocity and the ΔV in the space capsule's reference frame are both 0.   So in the space capsule reference frame the change in kinetic energy (KE = M*ΔV2/2 = 0 because ΔV=0).  Your earlier example that used the reference frame of the EM-Drive is flawed because the kinetic energy will always be zero even as the EM-Drive consumes large amounts of power.   You have to use an external fixed frame of reference.   When you do that CoE is violated and of course momentum is not conserved.   This is true for any reactionless drive.   I don't consider planetary assist to be reactionless propulsion because the planet is pulling the spacecraft and momentum is tranferred using gravity.
« Last Edit: 09/24/2016 09:47 PM by zen-in »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #936 on: 09/24/2016 10:47 PM »
.... When you do that CoE is violated and of course momentum is not conserved.   This is true for any reactionless drive.   I don't consider planetary assist to be reactionless propulsion because the planet is pulling the spacecraft and momentum is tranferred using gravity.
At the Estes Park Breakthrough Propulsion Workshop, Dr. Jean-Philippe Montillet of the École Polytechnique Fédérale de Lausanne, Switzerland, presented a paper titled "Model of the EM Drive with the EMG coupling" (that mathematically and physically) explains the EM Drive as a capacitor, where:

* Surface currents propagate inside the cavity on the conic wall (between the two end plates)
* electromagnetic resonant modes create electric charges on each end plate
* Mach/Woodward effect is triggered by Lorentz force from surface currents on the conic wall
* acceleration of RF cavity as due to the variation of Electro Magnetic density from evanescent waves inside the skin layer

A polymer insert placed asymmetrically in the cavity results in greater asymmetry, while decreasing Q. The cavity's acceleration is a function of all the above factors.  The model can explain acceleration with and without the polymer insert (to a more significant or less significant extent).

As the Mach/Woodward effect can be derived straight from the fully covariant nonlinear Hoyle Narlikar gravitational theory or it can also be obtained from linearized General Relativity it is really as much of a gravitational effect as gravity assist.  The difference being that gravity assist is something that people are now familiar with (since it was first used for interplanetary flight by the Mariner 10 in the mid-70's) and the Mach/Woodward effect is something that people are normally unfamiliar with (because time-dependent terms in General Relativity are usually ignored)

Gravity assist flight of a spacecraft is an open system where momentum is transferred by gravity to spaceship and so is the Mach/Woodward effect a gravitational effect.  Both of them are explained by General Relativity.  If somebody explains the acceleration of an EM Drive based on a gravitational effect (the Mach/Woodward effect), it would be incorrect to address conservation of momentum and energy solely based on the spaceship momentum while ignoring the effect of gravity.

Of course, nobody nowadays will write about "overunity" of gravity assist (as the spaceship involved in a sling shot maneuver apparently gains  velocity out of nothing, if one ignores gravity) because it is evident that gravity assist is ... gravity-assisted.

Similarly, the Mach/Woodward effect drive perhaps should be renamed "Mach Effect Gravity Assist" (MEGA) drive, to make it more obvious to the readers that the Mach Effect is a gravitational effect, and thus it would be completely incorrect to address conservation of momentum and energy without taking into account the gravitational effect.
« Last Edit: 09/25/2016 12:40 AM by Rodal »

#### MrFrankenverse

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #937 on: 09/24/2016 11:49 PM »
This rebuttal of the CoE over unity arguments seems pertinent: http://ssi.org/epi/Over-Unity_Argument_&_Mach_Effect_Thrusters.pdf

#### RotoSequence

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #938 on: 09/25/2016 12:02 AM »
At the Estes Park Breakthrough Propulsion Workshop, Dr. Jean-Philippe Montillet of the École Polytechnique Fédérale de Lausanne, Switzerland, presented a paper titled "Model of the EM Drive with the EMG coupling" (that mathematically and physically) explains the EM Drive as a capacitor, where:

* Surface currents propagate inside the cavity on the conic wall (between the two end plates)
* electromagnetic resonant modes create electric charges on each end plate
* Mach/Woodward effect is triggered by Lorentz force from surface currents on the conic wall
* acceleration of RF cavity as due to the variation of Electro Magnetic density from evanescent waves inside the skin layer

I'm sensing a link between the idea of EM drives as a capacitor, TheTraveler's anomalous impulse that he's had difficulty reproducing, and Seashell's (paraphrased from memory) "cyclic high impulse jerk..."

« Last Edit: 09/25/2016 12:03 AM by RotoSequence »

#### WarpTech

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##### Re: EM Drive Developments - related to space flight applications - Thread 8
« Reply #939 on: 09/25/2016 12:28 AM »

P.S. I saw HMXHMX say the videographers have to do some editing. Honestly, given the nirvana I imagine going on at this conference I would rather watch those videos unedited.

Not really. There were many times when the room turned into a fur-ball of multiple conversations all at once. Interruptions, everyone running out to see a rainbow, projector issues, dinner plans, etc. These parts of the recording would be useless to everyone and would make the resulting video much longer than it needs to be. We were in there for 3 whole days, I'd estimate there are probably at least 24 hours of video and audio to sift though and piece together into a coherent presentation. It would be a waste of the viewers time to listen to that garble.

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