## Mach Effect progress

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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GIThruster
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CaptainBeowulf wrote:The idea of feeding a rocket thruster "fuel" can still raise an objection: you are supplying power to the thruster from an external source, so it never really goes over-unity, while the M-E thruster is getting over-unity by operating without an external "fuel" source.
Honestly it doesn't matter. When you do the math the way GoatGuy proposes, any thruster will eventually go overunity. The higher the thrust, the more quickly it will go overunity. This isn't changed by putting limits on the fuel. Doing the math the way GoatGuy proposes, we could take literally any rocket thruster, put it on such a swing arm, and attach it to a generator. It would eventually produce more energy than it can account for because acceleration is linear with force but energy is quadratic with velocity. In fact, I think if you look at the problem carefully you find that you have the same issue with a DC motor.
This objection arises because people usually think of chemical rockets when they think of rockets. In the case of a chemical rocket like a hydrolox rocket, the "fuel" is both the power source AND the propellant.

Again, it doesn't matter where the thrust comes from, what the thrust efficiency is, etc. If the thruster puts out a constant thrust of any level--and they all do, chemical, electric, nuclear--then doing the math the way GoatGuy proposes will inevitably arrive in a failure to conserve energy. That's because the math is wrong. In all these instances, acceleration is linear with force, but energy is quadratic with velocity, so there will always be a velocity and hence some time t, that you have an overunity condition arise. The answer is not to say you can't have thrusters that generate constant force. It is to say you're doing the math wrong.

It would be interesting to see this method of GoatGuy and Andrew applied to Deep Space 1. It seems to me possible it has already gone overunity by these accountings. One could at the very least say when it is due to go overunity, given it produces a constant force.

I should note to you too, that because velocity and hence energy are relative, there are always circumstances where all thrusters will appear to violate conservation using this method. If GoatGuy had realized this he would have abandoned the method.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

CaptainBeowulf
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Once I got to the point in the evening where I had a bit of spare time and could try to play around with the math a bit, it struck me once again how this topic causes people, myself included, to not see the forest for the trees.

Ok, as we established a while back and you just repeated - acceleration is linear with force but energy is quadratic with velocity. So yeah, you can actually make an analogy to a chemical rocket too. Even though you're feeding it "fuel" - power source + propellant from an external source - with continuous thrust you could mathematically run it to the point where you appear to have more kinetic energy in it than the amount of energy in the fuel you've fed to it. So, if that math was right, you could then begin to harvest electrical energy from the flywheel and use that energy to manufacture more fuel to feed the rocket. Clearly, this doesn't actually work.

I'd be much happier if I knew the math well enough to understand where it's going wrong, or how to do it right... but I guess at a certain point you need to be a physicist.

Nonetheless, I think after the last page and a half of rehashing things I'm fairly satisfied that a hypothetical sublight M-E drive still has no serious thermodynamic issues. It expends energy which causes both it and distant matter to accelerate, just like a rocket accelerates itself in one direction and its propellant in the opposite direction. It cannot be run in "heat pump" mode whereby it extracts enough energy from accelerating distant matter to make the acceleration self-sustaining. Acceleration of distant matter doesn't mean that matter now has less entropy - it means that entropy has increased globally by burning fuel aboard the M-E ship to accelerate both the ship and the distant matter.

chrismb
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CaptainBeowulf wrote: acceleration is linear with force but energy is quadratic with velocity. So yeah, you can actually make an analogy to a chemical rocket too. Even though you're feeding it "fuel" - power source + propellant from an external source - with continuous thrust you could mathematically run it to the point where you appear to have more kinetic energy in it than the amount of energy in the fuel you've fed to it.
Capt B's comment is never true. Even if Capt B has been persuaded otherwise by some hand-wavyness.

Just because it is repeatedly claimed, and that it has been 'shown' elsewhere, it does not make it true.

If the frame of reference is rigorously observed (and it has to be for KE calculations) it is impossible to derive more energy than that put in.

It is simple to disprove that last statement - merely show the forum a mathematical calculation ending in over-unity energy gain, and it will either disprove the last statement, or will have an error in it.

The problem is when the inertial frame of reference is changed. If that is done then immediately stationary objects 'gain' KE. This is false maths. It is as inaccurate as to suggest a car generates enormous power by accelerating the earth beneath it, rather than recognise the accelerating car cannot be the frame of reference. Similarly, the frame of reference can be changed to hide other 'mathematical sleights of hand'.

It is better to stop with the 'blahblahblah' and start just putting some numbers down. Can someone show the forum this 'over unity' energy calculation, or is it impossible for them to do so (because there is no such calculation):-

Barry Kirk
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I'm not sure about the math here so, I'm making a couple of assumptions.

What are the implications of the following.

1. If an ME thruster accelerates, something happens, I'm being a bit vague here, but what happens is that energy is bled out of the thruster.

2. If an ME thruster moves out of a gravity well, it also bleeds out energy.

These energy loses would prevent the ME thruster from becoming a power source.

Perhaps it would manifest as a drag force on the mechanical vibration that would require energy input to overcome.

I saw something about a WarpStar which using fuel cells for a power source would be able to make a round trip to the moon with a very small amount of fuel mass fraction.

These energy losses would probably make such a vehicle impossible, but it still leaves the ME thruster as viable space drive. A ME thruster still has the potential to be much more efficient than a conventional rocket.

An ME thruster space vehicle would be much easier to power with a Nuke, or even beamed energy.

Here is another possibility.

Would ME thrusters make a space elevator easier to construct, using ME thrusters to reduce the "effective weight" at various points. You would have to power it by running power cables up the space elevator.

You might not need a space elevator to go all the way to Geo Sync.

Here is an example.

Build a power cable 200 miles long with one end at the ground and the other end some distance off the ground, most likely over 50 miles altitude.

Suspend the cable using ME thrusters at intervals with the ME thrusters powered from the power cable.

Power your ME thruster vehicle off of the power cable in the same way that an electric train is powered off it's tracks.

The power cable doesn't have to be straight. It could follow the same profile that a conventional rocket follows. IE, straight up at the beginning and than curve towards the horizontal.

Actually the flight profile would probably be a little different since the acceleration is more constant since vehicle mass is constant.

At this point your ME thruster vehicle is more of a booster stage.

Not sure if any of this makes sense.

GIThruster
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I don't understand what you mean by that energy is bled out of the thruster. If you could explain that I would respond to the following.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Barry Kirk
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Again, I don't know the math or the equations of the ME thruster.

But what if for example an ME thruster that is generating thrust and accelerating creates a force that counteracts the vibration of the mass. This force would tend to reduce the amplitude of the vibration and would require energy to be added to maintain the amplitude of the mechanical vibration.

This energy that needs to be added would prevent the ME thruster from actually generating energy.

The same mechanism could be used when an ME thruster travels out of a gravity well.

If that is the case, an ME thruster could be used as a power source as a vehicle is entering a gravity well. If that energy was dissipated with a braking resister, it might reduce a vehicle velocity and therefore heat shield requirements for a space craft on a moon or mars return.

GIThruster
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I'm still not entirely certain what you're saying but I'll take a shot at trying to answer your questions here.

M-E thrusters have electrical power in and generate stationary thrust. What makes them unique is they don't need propellant to do this, so they avoid the "rocket equation" and all the troubles this entails for space travel.

Not sure what your references to vibration are, but if you're talking about the mechanical cycle of the thruster, the energy lost here is all lost as dissipation or as result of the "loss tangent" of the ceramic used. That loss rate is well defined for most ceramics and typically runs from 0.01 to 0.1%. So even high loss materials are converting about 1/1000 of the power into them directly into heat that is wasted. In large assemblies of thrusters, that heat will be enough such that it needs to be removed, but at present this is not a concern. Commercial grade thrusters may well need thermal management systems but most spacecraft components do.

Paul March and I worked together on the WarpStar paper you're referencing. I'm glad more people have read it than the few who showed at STAIF '07. The point of that study was to take a baseline thrust efficiency measured in force/electrical power in N/W and look at the practical implications of this so far as space travel. STAIF is after all the Space Technologies and APPLICATIONS International Forum and we wanted to draw an illustration so people clearly understood what Jim's technology entails in the short term.

One of the implications of a working gravinertial technology is that we don't need expensive macro-engineering projects like cables or better known as "tethers". One criterion to make space travel cheap and ubiquitous is to remove it from reliance upon very large shared systems such as launch pads and mission control. I think we'll likely always see traffic control systems as we do with aircraft at least in busy areas, but private air strips often don't have more than a radio that sometimes, someone is on. We ought to be looking to emulate this "little as possible" requirement for space travel infrastructure, so building tethers is not high on the priorities list.

Rather than use M-E to build something like a tether, I'd like to see the technology applied to an interplanetary skycrane. Vehicles like the S-64 Sikorsky, and all tractor trailers, that transport cargo externally, are good models for future mass transport. Imagine a ship that can fly down into a parking lot and clamp onto a trailer that was just loaded at the factory or had just come off a ship or rail, and fly away with it. That's the kind of utility that would make spaceflight safe, quick, convenient and economical--the four hallmarks of any "golden age" in travel. If we can transport people and stuff like this, we can easily become a truly space faring people.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Barry Kirk
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GIThruster wrote:I'm still not entirely certain what you're saying but I'll take a shot at trying to answer your questions here.

M-E thrusters have electrical power in and generate stationary thrust. What makes them unique is they don't need propellant to do this, so they avoid the "rocket equation" and all the troubles this entails for space travel.
It's the stationary thrust part that I'm addressing. What isn't being addressed is an M-E thruster where the whole thruster "assembly" is accelerating or traveling in/out of a gravity well.

By way of analogy, an electrical generator should generate electricity for no energy input, except that the back EMF retards the rotation of the generator requiring mechanical makeup energy to be applied. That mechanical energy that is supplied is essentially being converted into another form, electrical energy.

In the same way, is it possible that an M-E thruster would have a analogous back EMF that would drain energy from it? This energy would have to be made back up thus preventing the M-E thruster from becoming a power source.

Sadly, that would make an M-E thruster a much less efficient means of getting to space. I'm not saying that it wouldn't be far more efficient than any existing rocket. Just that it would be less efficient than your talking about.

Even with such a power drain, an M-E thruster has the potential to make us into a space faring civilization, so the implications are huge.

Having said that, I'll go back to your "static" M-E thruster. In such a case there wouldn't be any power drain other than electrical resistance and the mechanical dissipation you talked about.

A "static" M-E thruster might make it possible or at least far easier to build very large towers and or or cables, the purpose of which would be to provide a power cable through which to power your WarpStar vehicle as it accelerates into orbit.

GIThruster
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There are actually a small handful of misunderstanding developing here and some of them are likely mine.

I don't think it's fair to say that an EMF back action occurs in an electric motor that is in any way significant so far as the performance of that motor is concerned. Maybe it is but I'm not familiar with that dynamic. I think rather, the big picture here is to recognize that an electrical motor is a transducer, that converts electrical force, energy and power into mechanical force, energy and power. Motors are tranducers but M-E thrusters are not. Primarily, they are gravinertial transistors. They don't convert electrical power into mechanical power so much as they control the flow of gravinertial flux and the force, energy and power that represents. So when looking at efficiency issues, the N/W rating for a gravinertial transistor is not a conversion rate, but rather just the working numbers the transistor needs be provided with and should be expected to generate. In short--if you don't keep in mind that an M-E thruster is a transistor, you will misunderstand what the efficiency rating represents.

For instance, what the 1 N/W thrust efficiency rating used in the Warpstar illustration really means is, one could use thus-and-such sized power system. If we have 1 N/W thrusters, we can power our interplanetary cruisers with fuel cells. In fact, we could power our launch systems with rechargable batteries. (This does however, also rely upon a reasonable thrust to weight ratio which Warpstar did not deeply examine as those papers are 8 pages max. I can tell you though that the numbers chosen were very reasonable.)

As far as the issues that arise when an thruster is traveling and especially when it is accelerating: to do this math requires things like Lorenz transforms. There are indeed engineers here in this forum who can do that sort of math, but in general they are the province of physicists which we do not have in house. It is IMHO therefore wise to steer clear of the issues that arise when you start talking about accelerating, non-inertial frames of reference, etc. It is wise to bear in mind that M-E thrusters develop constant stationary thrust, just like any other thruster, and leave it to the physicists to work out the implications of what this means once they start accelerating.
Last edited by GIThruster on Tue Jan 15, 2013 4:25 pm, edited 1 time in total.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Barry Kirk
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Just a minor point... I said Generators, not Motors... I was talking about Generators having a mechanical back force which is why you need a source of mechanical power to turn them.

GIThruster
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The "back reaction" against all acceleration is inertia, which is just what M-E devices manipulate. I don't think there is another back reaction involved which standard theory does not account for.
Last edited by GIThruster on Tue Jan 15, 2013 4:31 pm, edited 1 time in total.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Barry Kirk
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No problem...

CaptainBeowulf
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It is simple to disprove that last statement - merely show the forum a mathematical calculation ending in over-unity energy gain, and it will either disprove the last statement, or will have an error in it.

The problem is when the inertial frame of reference is changed. If that is done then immediately stationary objects 'gain' KE. This is false maths. It is as inaccurate as to suggest a car generates enormous power by accelerating the earth beneath it, rather than recognise the accelerating car cannot be the frame of reference. Similarly, the frame of reference can be changed to hide other 'mathematical sleights of hand'.
I think this is why the math becomes very difficult for the majority of us. It's a question of how to do the transformations of inertial reference frames of a thruster under constant acceleration. It appears that for someone remaining in the original reference frame and watching a thruster accelerate away, the thruster will appear to gain more kinetic energy than it should, so that at time t it will appear to go over-unity. GoatGuy's simple application of the math shows it go over-unity at such a point.

I believe that GoatGuy posted his math on the NBF forum years ago. These days he seems to just write long rambling posts like we do here. When I have time I'll see if I can find his equation.

IIRC GIThruster said that the math disproving GoatGuy's math was posted in detail on a mailing list. I don't know whether he feels comfortable copying the content of those messages here. I would like to see the disproof in detail, but I don't know if any of us here will follow it properly. GIT, please post the detailed mathematical disproof if you feel you can.

Beyond this, though, I think we're at a bit of an impasse. One option would be for us all to go buy some textbooks and work our way through to the end of 4th year undergrad physics - the furthest point that textbooks can take you (beyond that you go to grad school and have to write your own stuff). At that level we should in theory be able to redo the math for ourselves. However, I don't think any of us have a spare year or two to do this.

The other option is to continue to monitor Woodward's experimental regime and see if he ends up with a more consistent, and ultimately stronger, thrust signal. If he does, and he then goes on to self-contained devices, this subject will attract more attention. If there is a real over-unity issue someone who knows all the relevant math in detail will raise it. If there isn't, I'm sure people will write up detailed comparisons of conventional rockets to M-E thrusters in terms that we'll be able to understand. This is probably the easiest way to get the answer.

chrismb
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CaptainBeowulf wrote: It appears that for someone remaining in the original reference frame and watching a thruster accelerate away, the thruster will appear to gain more kinetic energy than it should, so that at time t it will appear to go over-unity.
No, this will never happen. Why does it appear this way to Capt B? If the observer and all his calculations remain in the original inertial frame, viz he is not subjected to an acceleration, the final KE of a system he observes will never exceed the energy expended in causing changes to that system.

The only complexity that arises, that does catch people out, is calculating a 'power' of a thrust based on the accelerating object as the point of reference, e.g. x amount of ejected propellant at y m/s = z kW.

This is false if it is attempted. The power expended in accelerating the propellant must also always be done with respect to the one, single, non-accelerating inertial frame, else the maths ends up in a right pickle. This is where most of the fallacies appear to come from.

Any equations you might find that suggest an over-unity outcome of KE versus expended chemical/electrical power will almost certainly have this fallacy, or similar, embedded within it.

Rockets follow the conventional laws of thermodynamics and of Newtonian physics. There is no doubt whatsoever.

GIThruster
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chris, I'm not a physicist, but I think the trouble people commonly find here is they fail to note that all thrusters generate constant stationary force. Although the force generated is constant when stationary, it is not when measured by an observer in the scenario you envision. The thruster is accelerating, and though its force is constant in its own rest frame, it is not constant when accelerating. I believe the proper terminology is to say that force is not "invariant".

Beyond that I'm not going to go. I'm just noting to you that this trouble only comes up when engineers pretend to be physicists and ignore the need to do transforms that is so obvious to the physicist.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis