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Registered Member #27
Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058
There are many things that points to this being complete nonsense with a high degree of certainty, but that does not prove anything.
Proving that this effect is not real is quite difficult and no amount of math will do that. If current theories are not in agreement with reality then it is the theories that needs to be modified.
We have two independent claims by Shawyer: 1. That some machine he built is generating thrust. 2. That he has some math that explains how it works.
The correctness of one does not affect the correctness of the other so they have to be evaluated separately.
To get a reasonable proof that the experiment is flawed or not we have to reproduce the experiment very accurately.
To get a good proof that the math is flawed we need to get hold of the complete set of equations and check if they are valid and free of assumptions. Showing that some other set of equations we make up ourselves does not generate this effect proves nothing.
It all really boils down to the principle that spectacular claims demands spectacular evidence. Shawyer has come up so short in that sense that there is little point in making any large efforts to verify his claims. Replicating the experiment might be worthwhile since it is pretty simple, if nothing else it can put a solid nail in the coffin of the whole idea.
The variation of Q with velocity violates the premise that inertial frames are indistinguishable from one another... This alone should set alarm bells ringing
Here are some musings on field stress and radiation pressure. I start with a derivation and then attempt to mage some general statements about what the total force on the cavity walls will be like assuming sinusoidally varying EM firlds within.
This is a somewhat simpler deduction based in consevation of momentum.
And, a simple photon illustration.
In short, momentum conservation is the key.. Time averaging removes high-frequency components to the force. If no field energy escapes the cavity, there is no thrust.
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
"In short, momentum conservation is the key.. " I'm not sure it is; the very fact that he is putting this forward as a reactionless drive indicates that he doesn't consider momentum to be conserved in this case. This is now a philosphical question- if you never consider anything that claims to violate your paradigm how will you ever know when it's time for a new paradigm? I don't think it's likely to work- particularly since running it in reverse also seems to violate the conservation of energy. On the other hand, I do accept that it is perfectly possible that those "laws" might be a simplification. After all, mass was thought to be conserved until Einstein's work. I don't think this bloke is the new Einstein; but just saying that you don't need to do the experiment because the result is impossible is exaclty the problem that Galileo faced from the "educated" men of his day. Neil's comment about cooling drafts and cables is probably the explanation of the "force" measured here but that's a reason for doing a better experiment rather than saying "It is imposible because it breaches our dogma".
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I read his paper and he seems to have been pretty careful measuring the thrust. The only thing I can see going wrong is if he used electronic balances and the microwave leakage interfered with them. But even so he controlled for that by turning the thruster upside down to see if the measured force changed sign (which it did.)
Still, if I was going to invest in the guy, I'd want him to dangle his whole engine from a balance beam and show me it move when he turned the power on. He claimed a thrust of 0.214N/kW from his bigger engine, well over 20 grams, which I bet would easily move a steelyard type of beam even with a power cable at the fulcrum. Cooling air and water would mess things up, but I bet it would run fine for a few seconds without cooling.
shawyer wrote ... In each series of tests, the test runs were repeatedly carried out with the thruster in both a nominal position (thrust direction vertically up, thus measured thrust is negative) and an inverted position (thrust direction vertically down, thus measured thrust is positive). In all tests the thruster gave the correct thrust direction...
Tests were also carried out with the thruster sealed into an airtight enclosure to calibrate out thermal buoyancy effects...
A total of 450 test runs were carried out using 5 different magnetrons. Input and resonant tuning positions were varied to give a range of thrust outputs from a maximum of 16mN, at optimum tuning, down to zero when totally detuned. Substitution of the design parameters and measured Q into equation 10 gives a theoretical thrust output of 16.6 mN which is in close agreement with the thrust measured...
Registered Member #29
Joined: Fri Feb 03 2006, 09:00AM
Location: Hasselt, Belgium
Posts: 500
Bored Chemist: I am prepared to accept "new paradigms" as you put it, as long as what the person says makes sense. This does not make sense. It is a misrepresentation of what "group velocity" is about and I have grave doubts about the experimental evidence.
Shifts in Q (as Steve C indicates) do not occur in moving cavities. The "educated men" of Galileo's day would not look through the telescope at the moons of Jupiter. I am attempting to question the results of a probable scam artist who is misrepresenting a reasonably well understood phenomenon. Invoking the "closed mind" argument is a sign of pseudoscience in action! If you don't believe what I am saying, why not go through a century and a half of electrodynamics yourself. There is nothing that indicates that the fundamental conservation laws can be violated. It is through ignorance that these scam artists ply their wares..
If someone offers experimental and/or convincing theoretical evidence to the contrary, I will eat every one of my words... In the meantime, as I said previously, I will not be betting the retirement fund on this gamble.... Will you?
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize
Registered Member #29
Joined: Fri Feb 03 2006, 09:00AM
Location: Hasselt, Belgium
Posts: 500
I'll cough up 50EUR to someone who does the experiment under Steve C's conditions and 150 EUR to the first person who does the experiment AND offers ideas on a coherent physical/mathematical theoretical basis for what is going on. In addition, if possible, we/he/she can submit a paper to Physical Review or IEEE Transactions.
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
Thanks for the link to the paper.
I'm interested in figure 2.4, which shows a single photon pinging off both ends and walls. It appears to be valid to equate the group velocity with the speed of light resolved normal to the end plate, so either can be used to compute the force on the plates. However it also neatly shows that the photons change axial velocity with each interaction with the sloping walls, the mean of the arrival and departure angle on the walls is, as you would expect from geometrical optics, normal to the wall, thus has an axial component. From first principles without wading into the detail, I can guarrantee that in a sttioanry system, the force on the walls equals the difference of the forces on the ends.
The change of Q with speed is interesting. He is using the relatavistic expression for the addition of velcoties, and he is adding the spacecraft speed to the group velocity of the wave. I'm not sure that is a valid thing to do, as the photon is not moving at the group velocity axially, but at 'c' at some angle. This is where I appeal for somebody else to do the maths and say what the direction of the resultant photon path, still travelling at 'c' will be, as a result of adding the craft velocity.
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
"Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize " OK. I take it you mean US dollars. IIRC the exchange rate is about $1.85 to the pound at the moment. If someone takes up the challenge and provides the evidence I will send you a cheque for £100 (there's a bit of leeway for exchange rate changes there) and you can forward it (that way the recipient doesn't get stung for 2 sets of currency fees if they happen not to be in the UK.)
If anyone is planning to take this on please send a note to this thread - if there are lots of folks building kit and we only pay out for the "first to publish" then there will be a lot of disapointed people.
Of course nobody here is going to accept responsibility for anyone microwaving themself to death or anything like that. (Apart from anything else, that would be cheating- the microwaves are not meant to escape).
Don't get me wrong, I think this is almost certainly bull. I'm just pointing out that if someone says "I have a toy that breaches the law of conservation of momentum" you can not logically say "That cannot be true because it would breach the law of conservation of momentum" as a refutation. (Of course, you an say that a zillion previous experiments have not shown that effect) That would be the same argument as saying "I know God exists because it says so in the bible".
BTW, this looks a bit like buying a lottery ticket- I can afford to trash £100 without much trouble. If it happens to work then I get to be associated with one of mankind's greatest discoveries. All I have to do now is dream of fame and fortune until the "draw".
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Yes I do mean US dollars. Thanks for your support BC!
I guess I should also define that the money (my $150 plus anything anyone else pledges) will go to the first person to post pictures of their experiment, and a link to a movie, on 4hv. We'll need some kind of proof that the pictures and movie were made by you.
Also, as a minimum I think I'd like to see something like a flashlight bulb lit by a small coupling loop in the cavity, to prove that you really did bother to generate some microwaves in there. I'm sure WaveRider can work out what size the coupling loop should be, to make sure the bulb won't light unless you hit resonance with a decent Q factor.
WaveRider: It would be cool to get a paper in some journal, jointly authored by you and a couple of us. Or maybe you could give the experiment as a project to one of your students? Now I think about it, the hardest part of the whole thing is probably designing a truncated conical cavity that has a resonant mode at 2.45GHz: we could use your help with that.
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