I engaged with a length argument on this very thready about that issue. And after reading that paper over multiple times the only thing clear in my mind is that I dont believe that essay is meant to answer the question we want it to answer. Yes I know that sounds absurd. I can even admit it sounds like denial. But its the only logical conclusion I can reach after reading that essay and arguing about it here. That last paragraph in that paper in particular feels pretty weird. how can you spend 3/4 of an essay arguing that you cannot arbitrarily choose a time to restart acceleration. But then at the end argue that is exactly what you would need to do.My gut tells me that if he actually believes a MET behaves in the manner described in that last paragraph then the only thing that he can be describing is the oscillating nature of the fluctuating mass in a MET device. which is constantly being accelerated and deccelerated as its mass fluctuates.Unfortunately I have no way of confirming if my gut feeling is accurate as I have no line of communication with Woodward or Fern.

To wrap this up, we ask: is it possible to do a correct calculation of the sort thatcritics did that does not lead to wrong predictions of the violation of energy conservation?By paying attention to the physics of the situation, yes, such a calculation is possible.

We routinely hear a criticism of METs based upon an argument that claims: if aMET is operated at constant power input for a sufficiently long time, it will acquireenough kinetic energy to exceed the total input energy of operation

Unfortunately I have no way of confirming if my gut feeling is accurate as I have no line of communication with Woodward or Fern.

...Light changing the mass of a dielectric: URL: Mass change of dielectric media induced by propagation of electromagnetic waves by C.Z. Tan

But the principle of the Mach Effect Thruster is that it is not the electrical energy of the onboard power source that is converted into acceleration. Instead, the powersource merely enables the creation of the gravinertial flux, which then exchanges momentum with the rest of the mass of the universe....Hence, if the Wheeler-Feynman absorber aspect of Woodward's theory holds true, the mechanism for the instantaneous exchange of energy with the rest of the Universe can be explained, and hence, indeed, a Mach Effect Thruster also doubles as a generator of local energy, leeched from the distant universe....Hence, from a local point of view, it does indeed represent a free energy device, but only because it is sourcing this energy from the closed system that is the entire universe. Thus, the surplus energy that is extracted here, thanks to the Mach Effect Thruster, is taken away from the entire rest of the Universe.So the net energy gain is zero. The system in which this takes place is just colossal - it is the entire Universe.

Does anyone have a digital copy of Woodward's book?I'm looking for a specific section of the book where he says he addresses an issue with his thrust derivation. I have not seen him address this issue elsewhere. I am in particular looking for pages 77 and 127.I'd like to be able to see how he addressed this issue, but I'm not going to buy a book to read two or three pages of interest.Thanks in advance.

I have the kindle version. Unfortunately those pages are the book page numbers not the ebook one so I couldnt provide you the information you want.

In the case of a rocket motor, the thing to observe is that there is one invariantvelocity involved: that of the exhaust plume with respect to the motor. All observers,irrespective of their own motions, agree on both the magnitude and direction of thisvelocity. And it is the velocity that yields momentum conservation. An argument basedon an incorrect application of Newton’s second law to METs was advanced as a criticismof Mach Effects by an Oak Ridge scientist many years ago. It is dealt with on pages 77and 127 of Making Starships and Stargates: the Science of Interstellar Propulsion andAbsurdly Benign Wormholes. It will not be discussed further here.

... Now as is always the case, internal forces (f) are always equal and opposite to one another, and so they sum to zero. Because the "rocket + some exhaust" system is in free space, it experiences no external forces either, so F=0. Remember that the force applied to the rocket by the exhaust is equal and opposite the force on the exhaust applied by the rocket. Since we have included this portion of the exhaust in our control volume, these forces are themselves internal, and sum to zero (see attached figure). Now if we applied F=ma we would get that 0=ma so a=0. Apparently rockets don't work....

Quote from: wallofwolfstreet on 03/30/2016 01:56 AM... Now as is always the case, internal forces (f) are always equal and opposite to one another, and so they sum to zero. Because the "rocket + some exhaust" system is in free space, it experiences no external forces either, so F=0. Remember that the force applied to the rocket by the exhaust is equal and opposite the force on the exhaust applied by the rocket. Since we have included this portion of the exhaust in our control volume, these forces are themselves internal, and sum to zero (see attached figure). Now if we applied F=ma we would get that 0=ma so a=0. Apparently rockets don't work....Your rocket works perfectly ! You have just forgotten that you have included in your rocket system all the plume delivered by its propulsion motor, so in fact the center of gravity of your whole rocket system does not move and so its acceleration a is zero even if the massive plume goes in one direction and the usefull rocket in the opposite direction ! One point that you seem to miss : The laws of galilean dynamics are valid only when expressed in a galilean referential (the natural referential attached to the rocket is not galilean as the rocket is accelerated and so is prone to fictious forces)To discriminate True forces from Fictious forces is rather simple : True forces are invariant when observed from different galilean referentials. By opposition Fictious forces change with the galilean referential from which they are observed.

Your rocket works perfectly ! You have just forgotten that you have included in your rocket system all the plume delivered by its propulsion motor, so in fact the center of gravity of your whole rocket system does not move and so its acceleration a is zero even if the massive plume goes in one direction and the useful rocket in the opposite direction !

One point that you seem to miss : The laws of galilean dynamics are valid only when expressed in a galilean referential (the natural referential attached to the rocket is not galilean as the rocket is accelerated and so is prone to fictious forces)

To discriminate True forces from Fictitious forces is rather simple : True forces are invariant when observed from different galilean referentials. By opposition Fictitious forces change with the galilean referential from which they are observed.

I gotta say, your derivation of a=0 is downright hilarious. You start by assuming the net force is zero, completely ignore the term you just got through saying was important (by setting it to zero too, in brazen disregard for the claimed operating principle of the device), and then declare that since there's no force (something you assumed a priori), there's no acceleration.

That's not what the Oak Ridge guys did, by the way.

An M-E thruster is not supposed to be a closed system. You can't declare F_{net} to be zero arbitrarily. This means you now have to address what v is, and since the transactional interaction is in all directions and largely due to the action of the distant matter rather than the power input to the device, you can't assign v=c.

I'd assign v=0, actually, under the assumption for the sake of argument that the theory is correct, but I have yet to arrive at a satisfactory theoretical demonstration of this. I think I've managed to show numerically that a naive application of the Doppler effect results in v being linear with the peculiar velocity of the thruster for small values thereof, but even if I haven't screwed up somewhere that's a pretty weak result... and I'm rather busy these days so I can't devote a lot of effort to this right now...

This would imply to me that you could place a control volume around the device and the radiating gravinertial field, and within this control volume F_{net}=0 because the Force on the MET is equal and opposite the force applied to the local gravinertial field (and hence it can be contained in a finite control volume).

Is the MET like a photon rocket, emitting gravinertial waves in place of photons, or is it like a charge in space, experiencing a force caused by some other, far off charge?

I don't understand how v=c logically follows from the above argument though.

What exactly are you applying the Doppler effect to here? The gravinertial wave emanating from the MET?

That's from your attempt to equate it with a photon rocket. Again, this seems to proceed from viewing the device as a pure gravity wave generator in a potentially empty universe, rather than something that exploits the mechanism of inertia to generate a large transactional (therefore locally instant) response from all matter within its cosmic horizon.

Yes. The cosmic redshift is isotropic, so it nulls out. But the Doppler effect due to the peculiar velocity of the source does not. So an M-E thruster should preferentially interact with matter in its direction of motion relative to the local comoving velocity, which in an expanding universe with a cosmic horizon might mean (I haven't proved this) that the mechanism is self-compensating with respect to the relative-velocity objection on the grounds of energy conservation. (I need to do some more thinking about how exactly this stuff works in the context of cosmic expansion; I may be barking up the wrong tree entirely. I should also read the latest papers and see if any of this is addressed...)

Given the theoretical justifications offered so far for MET's working they cannot work in an empty universe.

Not sure I get why this would be a problem?

This preamble has to do with the MET because mass fluctuations only lead to an apparent force within a closed system IF you take the INCORRECT F=ma approach as opposed to the more general F=d/dt(p) approach. If you have a closed system (i.e. nothing transfers across the system boundary) and you apply cyclic mass variations within the system, you would see that:F_{net}=(dm/dt)v + ma0=(dm/dt)v + ma (F_{net}=0 because the system is closed)0=0 + ma (since there is no flow of mass across the system boundary)***a=0And so (following this derivation) cyclic mass variation won't actually yield any propulsive benefits.Basically I want to see how Woodward addresses this issue, and whether it is done so in such a way as to make METs viable. I want to see why Woodward finds this argument "incorrect" as he says. Welcome other posters to point out any issues with this derivation as well of course.

Isn't that what I just said?

I propose you to make the modelisation of the Woodward device using the following scheme which relies only on the law of Force Equality betweeen Action and Reaction....

Exactly the same argument applies as with the rocket - what happens when that gravinertial radiation leaves the control volume? And you can't claim the thruster itself isn't generating force until then, because you can always draw the box smaller so that the wavefront in question has already left.

More like the latter, I think. Remember; this device is supposed to be tapping into the mechanism underlying inertia. If you view it as a simple non-transactional radiator, you are ignoring the Machian interaction and thus missing the whole reason it's supposed to work.