Author Topic: EM Drive Developments Thread 1  (Read 797128 times)

Offline Star One

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Re: EM Drive Developments
« Reply #60 on: 08/01/2014 10:35 PM »
The nasa link is to an abstract only- it says abstract only available. One presumes the rest of the paper will be available after peer review.
Glad to see this has been investigated.

That would be best. The reporting on this & reaction online in places has been atrocious, it reminds me of the reporting and reaction to both the faster than light neutrinos & ancient gravity waves. The former was an error and the latter has taken a terrible battering under peer review. I'll be interested to see how this gets on with peer review.
« Last Edit: 08/01/2014 10:38 PM by Star One »

Offline Cherokee43v6

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Re: EM Drive Developments
« Reply #61 on: 08/01/2014 10:38 PM »
em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.
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Offline Star One

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Re: EM Drive Developments
« Reply #62 on: 08/01/2014 10:40 PM »

em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.

I think even if the EM thruster actually worked as advertised that it's my understanding you would still need a jet engine for an aircraft or rocket for a spacecraft to get off the ground in the first place.

Offline Cherokee43v6

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Re: EM Drive Developments
« Reply #63 on: 08/01/2014 10:41 PM »

em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.

I think even if the EM thruster actually worked as advertised that it's my understanding you would still need a jet engine for an aircraft or rocket for a spacecraft to get off the ground in the first place.

Exactly my point.
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Offline Star One

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Re: EM Drive Developments
« Reply #64 on: 08/01/2014 10:43 PM »
Can I ask as a layman is part of the problem here with anyone analysing this that only an abstract has been published, no doubt because they are waiting peer review?

Offline CriX

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Re: EM Drive Developments
« Reply #65 on: 08/01/2014 11:40 PM »
I know very little about this, but it doesn't seem to claim free energy.  Sonny describes the "q thruster" as being essentially like a water propeller, except pushing against vacuum virtual particles.... which sounds plausible... to these foolish ears.  It's definitely disconcerting that even their null device produced "thrust" though.
The end result for these propellantless propulsion devices is free energy, though.

Damnit!  I really want to believe that this is possible.  It seems "fair" that we should be able to spend 2 MegaWatts and get some momentum in exchange.  I hope you've not adequately looked into this.

Offline brokndodge

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Re: EM Drive Developments
« Reply #66 on: 08/02/2014 12:18 AM »
I'll be interested to see what changes they made to the "null" device and why they believed that those changes would prevent it from producing thrust.

Offline cuddihy

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Re: EM Drive Developments
« Reply #67 on: 08/02/2014 05:18 AM »
Chris robotbeat's point only holds if you start from the assumption that it can't work. Once you start there, you can then draw your system box in such a way that it excludes the claimed source of momentum/energy. QED you now can call it  'free' energy.
Of course, the argument is a tautology, and it's a way of dismissing the claims on their face by refusing the initial assumptions, but it comes up any time Woodward or White's work are being discussed.

That said, the paper linked clearly says the device constructed to not get results got results anyway, so QED the resonant cavity theory is falsified by this experiment... So not sure why anyone's excited...

Online Robotbeat

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Re: EM Drive Developments
« Reply #68 on: 08/02/2014 05:23 AM »
You could use this device to harvest energy from the Universe one way or anoter. But anyway, in my opinion it's at least as bad to violate conservation of momentum.
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Offline Optimistic Brian

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Re: EM Drive Developments
« Reply #69 on: 08/02/2014 05:53 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.

Online Stormbringer

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Re: EM Drive Developments
« Reply #70 on: 08/02/2014 06:32 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.

it is my opinion that because there are at least 5 instances of this general class of scheme that have had positive results that there is something to it.

1. Woodward's version is tested on a torsion balance in a vacuum chamber with atmosphere evacuated. he has shown thrust.
2. This present Shafley resonant cavity thing.
3. the Chinese version of this which was developed from number 2 above because he could not get anyone else interested. they report thiers is ten times as powerful at 100 to 500 mN.
4. Dr Whites QVPT. he has positive results too.
5. the Egyptian Girl's version of this thing. hers uses the dynamic casimir effect. hers is being considered for satellite maneuver and station keeping.
« Last Edit: 08/02/2014 06:37 AM by Stormbringer »
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Offline KelvinZero

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Re: EM Drive Developments
« Reply #71 on: 08/02/2014 07:49 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

The energy may in fact come from somewhere else. That is fine. What I just do not understand is proponents not admitting to themselves how fundamental a gift this would be.

Alternatively, perhaps this effect is somehow tied to a local reference frame, like pushing against water or solar wind. This would make it far less effective but still would be a vast improvement over the rocket equation. I dont know what would define that frame since I haven't seen any claim that this is the case.

Not investigating these simple aspects with awesome consequences is like not taking your own claim seriously. Similarly with anyone proposing FTL without investigating how the paradoxes would be resolved. If you cannot describe these cases then you cannot describe what you are claiming to have produced.

Offline QuantumG

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Re: EM Drive Developments
« Reply #72 on: 08/02/2014 08:05 AM »
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

Maybe it doesn't, ya know.
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Offline KelvinZero

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Re: EM Drive Developments
« Reply #73 on: 08/02/2014 08:27 AM »
Perhaps I should have qualified that.. :)

Offline IslandPlaya

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Re: EM Drive Developments
« Reply #74 on: 08/02/2014 10:21 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

The energy may in fact come from somewhere else. That is fine. What I just do not understand is proponents not admitting to themselves how fundamental a gift this would be.

Alternatively, perhaps this effect is somehow tied to a local reference frame, like pushing against water or solar wind. This would make it far less effective but still would be a vast improvement over the rocket equation. I dont know what would define that frame since I haven't seen any claim that this is the case.

Not investigating these simple aspects with awesome consequences is like not taking your own claim seriously. Similarly with anyone proposing FTL without investigating how the paradoxes would be resolved. If you cannot describe these cases then you cannot describe what you are claiming to have produced.
*If* the effect is real I would speculate (as I have done before in other threads) that the kinetic energy your device gains during operation is always less than the energy input into the device.
This ties the effect to a local reference frame as you state. I would further speculate that this reference frame is the CMB rest frame.
See http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from for a discussion...
Now this is a lot of handwaving and I don't know what mechanism would be involved, but it would address the free-energy objection.
I think  ;)

Offline KelvinZero

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Re: EM Drive Developments
« Reply #75 on: 08/02/2014 10:37 AM »
Heh.. thats quite cool.. and with a 400km/s relative velocity we should be gaining energy, not expending it at least to begin with.. Just put on the brakes and end up shooting from our solar system at a pretty fair clip!

http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation#CMBR_dipole_anisotropy

what is in exactly the opposite direction of in the direction of "galactic longitude l = 263.990.14, b = 48.260.03" anyway?

Offline IslandPlaya

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Re: EM Drive Developments
« Reply #76 on: 08/02/2014 10:53 AM »
Not sure if you missed the /sarc tags in the first part of your post.  ::)
"Putting the brakes" on to be at rest wrt the CMB would take the same amount of energy (with caveats due to special relativity) as would accelerating to 400km/s in any direction.

Offline mboeller

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Re: EM Drive Developments
« Reply #77 on: 08/02/2014 11:35 AM »
first device:  www.emdrive.com
second device:  www.cannae.com

good discussions (2 threads) can be found here, including a lot of links:
http://www.talk-polywell.org/bb/viewforum.php?f=10&sid=3b93a639a0baff9ff89938b7b90beebd
« Last Edit: 08/02/2014 11:36 AM by mboeller »

Offline KelvinZero

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Re: EM Drive Developments
« Reply #78 on: 08/02/2014 11:39 AM »
No sarcasm. I don't understand the method in this thread and as far as I know it has not mentioned pushing on a particular frame, but I am pretty sure you would have to gain energy, or it is a mystery where that energy is going. In any case the important thing is that the amount of energy expended goes up proportional to the square of your current velocity relative to this medium.. otherwise, free energy.

The obvious example is movement in air with a propeller. This is an example of where pushing against some medium is sort of like propellantless propulsion and it would obey the classical velocity squared rule. However you would not have to expend any energy just to come to rest with respect to the air, in fact you could gain energy while doing so. For example you could allow the wind to turn the propeller, generating energy like a windmill and creating drag until your velocity matched that of your surroundings.

Offline CapitalistOppressor

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Re: EM Drive Developments
« Reply #79 on: 08/02/2014 12:05 PM »
The abstract just doesn't give enough information.

That said, there appear to have been three items tested on the rig, including an inert object and two test articles, one of which was modified so as not to produce thrust.

The fact that the modified one still produced thrust is a problem.  But we don't know the modifications.  It seems apparent that they were feeding energy into the modified test article.  Otherwise they wouldn't have needed an inert object.

As it is they are saying the inert object did not do anything, while both the engine and modified engine achieved measurable thrust. 

This would maybe make sense if the modifications were to the shape of the container, and were intended to test the theoretical predictions by the inventor. 

There is some supposed theory from the US inventor Guiddo Fetta underlying his Cannae Drive which seem to point to the shape of the container affecting the thrust.  I could see them modifying the shape of the container to test that hypothesis.  If flooding the modified container with microwaves also produced thrust it would mean the shape does not affect the thrust and you have bad theory.  But that doesn't necessarily mean you don't have an effect.

Frankly the seeming violation of conservation of momentum makes it extremely likely that there is an experimental problem.  The fact that the modified engine still produced thrust is a minor issue in comparison.



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