interesting discussions going on at the NASA Spaceflight Forum (which now has its own Woodward Effect thread, instead of using the generic "propellantless propulsion" thread.
PaulMarch wrote:Folks:
Noting up front that Dr. Woodward prefers "Mach-Effect" (M-E) instead of the "Woodward-Effect" descriptor of his discovery, you folks haven't asked WHY should a time rate of change of internal energy combined with the bulk acceleration of the energy storing media create the M-E's posited inertial mass variations in the first place. Woodward merely points to the M-E’s math derivation and indicates that is what the math says ought to happen and then experimentally looks for the predicted inertial mass variation effects and goes from there. Jim does provide though a two dimensional analog in his book of an accelerated mass that creates “Kinks” in the ambient cosmological gravitational (g) field that somehow transiently shields the local accelerated mass from the cumulative inertial effects of the cosmological g-field and that transient shielding effect is what gives rise to the accelerated mass’s inertial mass fluctuations. I could buy that if the M-E didn’t have one other requirement that leads to some very strange predictions.
Woodward also posits that due to the fact that inertial reaction forces apparently occur instantaneously, (I can’t find any experiments that have directly measured this assumption.), that the M-E's posited gravitational effects with the mostly distant mass-energy in the causally connected universe that give rise to the M-E have to interact effectively in no-time. I.e. it’s Einstein’s famous “Spooky action at a distance” problem. And IMO it is a problem in this regard, for how does an instantaneous g-field interaction in spacetime, TRANSIENTLY shield a locally accelerated mass from the rest of the cosmological g-field? It would be nice if Dr. Woodward could explain to us how instantaneous g-field like Wheeler/Feynman radiation reaction forces can give rise to transient effects that take time to occur in the local laboratory frame of reference.
Best,
PaulMarch wrote:This is Woodward's reply to my previous question:
"Paul,
So you've become a critic after all these years? The answer to your question is on page 262 of the book.
The instantaneity of inertial reaction forces simply means that whenever something is pushed, the reaction force on it appears instantaneously. So if the thing pushed is extended, but rigid, there are no Mach effects (as explained repeatedly in Chapter 3 of the book) because the acceleration and reaction takes place simlutaneously throughout the body. But when an extended body does not react rigidly (and it absorbs internal energy), the effective mass of the body during the acceleration becomes a function of time, and the math of Chapter 3 follows in an elementary fashion.
You may want to review Chapter 2 as well, where the action-at-a-distance character of inertial forces is explained.
Troll physics: fill the bottle with water, push it back, empty the bottle of water, pull the bottle towards you. Repeat, obtaining reaction-less drive. Problem, Newton?
But with a capacitor instead of the bottle, so you can confuse yourself about the mass-energy movement and it's momentum. I'm thinking I'm going to get annoyed with this thing in the coming days and draw the troll science variation.
edit: on one hand its of course good to see them actually put this to the test, on the other hand what you have there is they either claim that mass energy equivalence is wrong or it is equivalent to troll variation with a bottle of water. Charging a capacitor should, in terms of mass movement, be no different from filling a bottle, except the amount is tiny and impulse of a flow of current through two wires in opposite directions is a zillion times more confusing than impulse of a flow of water through a pipe. Local conservation of energy and mass energy equivalence implies that it should work no different, gravitationally, from filling/emptying a squeezebottle through a pipe. The charging current in the wire pair has to have momentum. It does, by the way of electrons going along gradient in electric potential, and the electrons going along the - wire having more energy than electrons returning through the + wire.
You can do anything you want with laws except make Americans obey them. | What I want to do is to look up S. . . . I call him the Schadenfreudean Man.
Charging a capacitor should, in terms of mass movement, be no different from filling a bottle, except the amount is tiny and impulse of a flow of current through two wires in opposite directions is a zillion times more confusing than impulse of a flow of water through a pipe.
Moronic comments like this, written by people who have obviously never spent five minutes trying to understand the theory, are the biggest reason why Woodward never addresses criticisms online. The world is full of idiots like this, pretending they have found something no one else has found when in fact, they haven't spent two minutes trying to understand the theory they're criticizing. This above is just stupid in a can. BTW, for anyone who would likewise confuse the motion of electrons for the proposed motion of the gravinertial flux into and out of the active mass, let me remind you that the mass fluctuates at twice the frequency of the drive signal--so there cannot be any experimental error driven by the flow of electrons. This above is just idiotic.
It's important to note there have never been any criticisms from the peer review literature. They only come from the irresponsible and ignorant.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
GIThruster wrote:It's important to note there have never been any criticisms from the peer review literature
I suppose that November 2001 publication by the Power Electronics and Electric Machinery division of Oak Ridge National Laboratory (ORNL), by unnamed authors, does not really qualify as "peer reviewed".
The set of experiments that Woodward and Fearn have done over the past year makes clear, at least to me, the Mach effect is real. The open question at this time is if it can be scaled up to produce useful thrust.
Woodward indicated in a recent email that there is reason this might not be possible and that the thrust might be no better than the proposed "photon rocket". He will soon do the next round of experiments, with better materials, to answer this question. I guess we all have to wait an additional 6 months or so to find out.
I read on NBF that White is going to make presentation on his warp field experiments at some starship conference in Dallas in August. Since he is focusing on this and not his QVF thruster concept, I assume the latter did not work out as expected.
Betruger wrote:Are the details of that reason confidential?
No.
Woodward met with Carver Mead, who presented him with the math showing the thrust from a mach effect device is limited to photon rocket levels. The details are in an email on the email list. I suggest you join the email list. "GIThruster" has the details on how to get added to the list.
I thought he'd already observed reproducible thrusts well in excess of photon rocket performance... He's not losing kilowatts into his test articles, is he?
kurt9 wrote:The set of experiments that Woodward and Fearn have done over the past year makes clear, at least to me, the Mach effect is real. The open question at this time is if it can be scaled up to produce useful thrust.
Woodward indicated in a recent email that there is reason this might not be possible and that the thrust might be no better than the proposed "photon rocket". He will soon do the next round of experiments, with better materials, to answer this question. I guess we all have to wait an additional 6 months or so to find out.
I think you may have misunderstood the conversation. Paul March was the one who said if we can't get better than transducer action we have only a photon rocket. Basically, if we can't draw force from the negative inertia of negative mass, we can't have the kinds of high thrust efficiencies we'd really like. I discussed this with Jim back in 2006 and I'm pretty sure he believes tapping into negative mass is expected. In fact I think it's possible his current experiments are doing this. He is planning higher frequency experiments soon so we should see some decent thrust figures from them.
I read on NBF that White is going to make presentation on his warp field experiments at some starship conference in Dallas in August. Since he is focusing on this and not his QVF thruster concept, I assume the latter did not work out as expected.
Sonny was instructed to focus on the warp issue rather than test his MLT. . .er. . .I mean his QVT. I would not expect any thrust from the QVT in DC operation. Paul March has been saying for a couple years now they're going to put one of Jim's current design thrusters on the Eagle balance but I haven't seen any sign when that's going to happen. I think Sonny would need to turn up a null result on his warp field and his QVT before he would consent to put an M-E thruster on his balance.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
93143 wrote:I thought he'd already observed reproducible thrusts well in excess of photon rocket performance... He's not losing kilowatts into his test articles, is he?
No. Jim's only been dissipating about a watt of power in the current experiments. He is planning however to go to some higher power thrusts soon--I'd guess 3-400 watts.
The comparison to photon rockets was really just Paul March's imagery as to how poor the thruster will operate if it can't access negative inertia. He's right. Without that sort of contribution M-E Thrusters would only be electric to kinetic transducers rather than gravinertial transistors. It's the later and the ability to tap into negative mass that makes them such an exciting possibility.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
kurt9 wrote:Woodward met with Carver Mead, who presented him with the math showing the thrust from a mach effect device is limited to photon rocket levels. The details are in an email on the email list. I suggest you join the email list. "GIThruster" has the details on how to get added to the list.
My take away from the notes about the meeting with Carver Mead was that Jim has never really focused his attention on the conservation issue. Since Carver did, he's taking it more seriously. Still, Mead's observation was just one of the two historic objections to M-E physics--basically that unless one identifies a second power source into the thruster, power out is limited to the electrical power in. Obviously so. This is why we have to look at the MET as a transistor rather than a transducer, IMHO.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
This site has some good general level discussion of why reactionless drives would normally be limited to photon drive efficiency (it does not address M-E drives directly):
1. There is a special frame of reference. In this case, the "reactionless" drive is really pushing against an infinitely massive special frame of reference.
(ed note: which means you've just destroyed Einstein's Relativity, with all the collateral science damage that implies)
or
2. There is no special frame of reference. In this case, the only way to sort of preserve conservation of energy is to limit drive efficiency to that of a photon drive. This is not a very useful drive, though, since it has the same (low) performance as a photon drive.
(ed note: the photon drive, where one lousy Newton of thrust takes three hundred freaking megawatts!!)
Woodward noted in his e-mail that if Mead's argument holds, what's he's done is essentially build a lab-scale gravity wave generator. That in itself would be a significant accomplishment, since standard gravity wave physics has predicted that this would not be possible. Nonetheless, the whole thing would IMO hold together theoretically: the lab-scale gravity wave generator, remodeled into a thruster, could produce thrust at photon drive level, agreeing with the established physics points made above (conservation of momentum and energy + Einstein relativity).
The point as I see it is that if the lab-scale gravity wave generator works while agreeing with the established physics framework, it strongly suggests that Wheeler-Feynman radiation-reaction is responsible for a gravinertial field throughout the causally connected universe (possible it bounces back at us when it hits our future particle horizon). This in turn means that Woodward's ADM negative bare mass electron model may well be right, or at least on the right track. That in turn means that you may still be able to expose the negative bare mass of the electron, which would allow the Woodward scheme to work (or perhaps an even simpler one - see the concept of "negative mass drive").
Also, Fearn seems to think that they may have previously underestimated the thrust they were getting, rather than overestimating it.
WRT to the ArsTechnica conversation, I would note that what is local conservation of momentum is in fact a somewhat hazy construct. What is the local frame? Normally you should definitely be able to see a back-reaction on whatever you are pushing against when you make something move. So, with a rocket you can see the propellant being exhausted out the back. When you walk around or drive a car, you don't see the Earth's rotation affected because it's just too massive compared to you, but in fact we all transfer a little bit of momentum back and forth from the planet when we move. However, the whole local Earth system conserves momentum, so it really makes no difference. If the entire causally connected universe is interconnected by a W-F gravinertial field, then it is all "local" if you can find a way to push/pull on that field. Only further experimental work can demonstrate if the W-F gravinertial field is correct or not. I want to see more work done just at the level of theoretical interest, even if it doesn't lead to a working spacedrive.
kurt9 wrote:The set of experiments that Woodward and Fearn have done over the past year makes clear, at least to me, the Mach effect is real. The open question at this time is if it can be scaled up to produce useful thrust.
Woodward indicated in a recent email that there is reason this might not be possible and that the thrust might be no better than the proposed "photon rocket". He will soon do the next round of experiments, with better materials, to answer this question. I guess we all have to wait an additional 6 months or so to find out.
I think you may have misunderstood the conversation. Paul March was the one who said if we can't get better than transducer action we have only a photon rocket. Basically, if we can't draw force from the negative inertia of negative mass, we can't have the kinds of high thrust efficiencies we'd really like. I discussed this with Jim back in 2006 and I'm pretty sure he believes tapping into negative mass is expected. In fact I think it's possible his current experiments are doing this. He is planning higher frequency experiments soon so we should see some decent thrust figures from them.
I now remember discussion about the importance of the 2nd term effect (negative mass) from the basic math being necessary for useful thrust, not just for wormhole possibilities. Somehow I got this and the related issue involving the necessity for bulk acceleration of the dielectric material used to realize Mach effect mixed up in my head.
In any case, Woodward seems to take Mead's concerns seriously.
Jim's May 10, 2013 weekly e-mail distribution post should shed some light on the Carver Mead "graviton" rocket thrust limit conjecture in regards to the M-E.
"To recap Carver's argument, he noted that both gravity and electromagnetism, as long range fields, have zero rest mass field quanta (assuming that gravitons actually exist of course). As such, one can simply write E = pc for the energy and momentum carried by the field. Now, if a MET produces thrust by completely converting the power applied to it (that is, dE/dt) into the equivalent momentum flux in the field, then the momentum flux will be dp/dt = (1/c)dE/dt and this is the thrust. As an example, if dE/dt = 100 watts, then dp/dt is a third of a uN. I'm going to call this relationship between power and thrust the "Mead limit".
There are a couple of questions here. Can METs beat the Mead limit? If they do, is there supporting plausible physics that underpins such behavior? The first question is one for experiment. The second one for "theory". Tonight's email chiefly addresses the first question. For if the Mead limit is found to apply in fact, then the second question is one for casual speculation at best.
Several weeks ago, I decided to go after the experimental question by building a device designed to run at higher frequency, one that would exceed the Mead limit if it could be made to perform as well as the devices that have been running now seemingly forever. Then, last weekend, it dawned on me that the answer to this question was already present in the data that these devices have been producing for upwards of a year. Indeed, the behavior is present in plots in chapter 5 of the book already. And it is especially obvious in the constant frequency runs that have been featured in the last few email attachments. Talk about feeling foolish. Especially galling is that there is a cheap tourist trick of analysis that makes interpretation of the data, at least in approximation, trivial. But on to the file (that will be attached to a following email).
The first dozen slides are selected from those sent last week. They include some pictures of the apparatus and the results for the 10 second steady power/thrust test. Immediately following are slides (13 through 16) with the results of a 14 second steady power/thrust test done after replacement of the lower flexural bearing in the balance. They are essentially identical to the shorter interval test. That is, after an initial transient thrust pulse lasting a couple of seconds settles, a steady thrust of a micronewton or two ensues. When the device is switched off, there is a prominent thrust pulse of a couple of seconds duration that quickly settles. The steady thrust, the focus of earlier attention, is right about at the Mead limit for this device. So it cannot be used to settle the question of exceeding the Mead limit.
Until last weekend, the obvious thrust switching transients, noted many time in earlier work, were simply noted and ignored. Last weekend, however, I paid attention to the transients. For two reasons. First, Carver's argument has an implicit assumption: the relationship between thrust and power is: thrust = constant X power. Always. This may be intuitively likely. But it is not necessarily so. If it is so, then the thrust transients in the displays MUST be accompanied by transient power surges that produce them. That is, the voltage squared (proportional to the power) traces (dark blue) should show signs of power transients that produce the thrust transients.
The cheap tourist trick observation is that the thrust balance, as far as transients are concerned, behaves as a "ballistic pendulum". A horizontal and damped pendulum -- which complicates careful analysis -- but a ballistic pendulum nonetheless. If your introductory physics text was Sears and Zemanski, you'll remember that they have a chapter on impulse, force and energy, with the ballistic pendulum as an example. Rudimentary analysis requires only elementary algebra. Impulse is force times time = change in momentum. Shoot a bullet into a block of wood suspended on strings, and the bullet plus block acquires kinetic energy equal to that of the bullet before inelastic impact. The block rises on strings until its potential energy in the gravity field equals the initial kinetic energy. You can compute the velocity of the bullet without fancy timing apparatus.
In our case, the two second thrust transients recorded MUST be produced by a force transient that satisfies the force times time condition to be equal to the thrust times 2 seconds. Especially obvious in the case of the outgoing transient, there is no corresponding power transient that the Mead analysis requires to be present. This is less obvious for in incoming transient, but it is also true there. This can be seen by inspection of slides 18 and 19. Depending on the duration of the power transient assumed, the dark blue traces should show VERY pronounced deviations from simple rise to and fall from steady power supporting the steady thrust condition. No, there is nothing in the system that would filter out such power transients. The implicit assumption in Carver's argument is as a matter of fact wrong in this case.
You may be thinking, gee, that's weird. If power transients aren't producing the thrust transients, what is? The Mach effect. Remember, the first Mach effect is NOT proportional to the power. It is proportional to the rate of change of the power (that is, dP/dt). So simply turning the device on and off should produce transients. Everything needs to be tuned to produce the Mach effect of course. But that does not depend on power transients beyond the simple switching of the power. The size of the transient thrusts should depend on how quickly the power is switched. Power switching is effected by the closing/opening of a relay that controls the driving signal to the power amplifier. One may expect the rise time of the power to be a bit slower than the fall time in these circumstance, and accordingly that the outgoing thrust transient will be a bit larger than the incoming transient.
The data acquisition rate for the routinely stored data is 100 Hz, so detailed analysis of fast transients using it isn't possible. But in slides 18 and 19 it is possible to determine that the rise time is at least a few ms and fall time is less than 10 ms. The cheap trick comes in here. The Mach effect thrust pulse that produces the ballistically measured thrust pulse of 2 s duration is just the measured average of the thrust pulses, say, a few uN, times 2 s divided by the rise/fall time, less than 10 ms. That is, the measured thrust transients tell you that the Mach effect switching transients are on the order of at least hundreds of uN. Given that there is no corresponding power transient, the Mead limit is far exceeded -- indicating that Carver's argument does not apply to these devices AS A MATTER OF FACT. Since Mach effects are derived from elementary physics first principles, we see that the assumption that thrust = constant X power always is false. Heidi and I, and others, are working on how this all works in detail. It is not a trivial problem."
In other words how you get around the Mead thrust output limit is by maximizing the M-E equation's first term's time rate of change of input power or dP/dt. That is when you start extracting from or dumping energy into the G/I field.