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BigBad

Mon Mar 04 2013, 03:29AM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
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Posts: 600

<Grins and shakes head>

So what are you claiming? You turn it on and off, and it's gained a certain amount of speed?

What happens if you do that twice? Gains twice as much speed?

Kinetic energy is 0.5 m v^2

So if you've turned it on twice, you've gained 4 times as much energy as turning it on once.

Three times? You've gained 9 times as much energy.

Where did the extra energy come from???

You can easily show that turning it on and off enough times, and you've got a perpetual motion machine, with more energy back than you put in.

2Spoons

Mon Mar 04 2013, 05:09AM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
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You are not making sense. Read my post again. Engage brain. Electrical energy goes in > convert to microwaves > into cavity > generates force > generates acceleration > results in transfer energy from cavity to kinetic energy, which originally came from electrical source. No magic. No breaking of conservation of energy. Switching on and of is completely irrelevant.
Have you ever noticed how you can turn on an electric motor, let it spin up a bit, turn it off, and it keeps on spinning?! Turn it on again and it goes faster!

Patrick

Mon Mar 04 2013, 05:34AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

the ultra-light impulse means, if your not careful in choosing a course, space dust and solar wind can oppose you desired direction. (and if the unwanted naturally occuring forces are not throughly random with time, direction, and intensity, youll have a significant deflection.)

Mattski

Mon Mar 04 2013, 06:10AM

Registered Member #1792 Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527

Dr. Slack wrote ...

Quote from the wikipedia article - "Any claim of a reactionless drive is treated with skepticism by the physics community, since reactionless drives violate the well-established principle of the conservation of momentum, which has enormous experimental support. Shawyer claims that his drive does not violate the conservation of momentum"

But that's just scientists. However if a furry thinks it works ...

Now now, don't imply that furries can't be scientific.

Shawyer claims that the force on the narrow end is smaller than the force on the wide end, and his derivation of the force imbalance seems reasonable. But there will also be a force on the tapered sidewall between the two ends for the same reason that there is a force at the ends themselves, and this is probably where the missing force is hiding, and when this is added back in the net force should be zero as would be intuitively expected for a sealed resonator.

If somebody claims to have violated conservation of momentum or energy then expect big proof before believing them...

edit:

2Spoons wrote ...

...
results in transfer energy from cavity to kinetic energy, which originally came from electrical source. No magic. No breaking of conservation of energy.
...

And just how does this energy in the cavity turn into kinetic energy? The energy stored in the cavity can decrease through heat producing loss mechanisms (resistive current flow in cavity walls or dielectric loss) or by leaving the cavity. If the cavity is perfectly sealed, superconducting, and filled with a vacuum then the energy in the cavity does not decay, and so any acceleration would imply either non-conservation of energy or some unknown mechanism by which electromagnetic energy can be lost in a resonator.

BigBad

Mon Mar 04 2013, 03:25PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
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Posts: 600

2Spoons wrote ...

You are not making sense. Read my post again. Engage brain. Electrical energy goes in > convert to microwaves > into cavity > generates force > generates acceleration > results in transfer energy from cavity to kinetic energy, which originally came from electrical source. No magic. No breaking of conservation of energy. Switching on and of is completely irrelevant.
Have you ever noticed how you can turn on an electric motor, let it spin up a bit, turn it off, and it keeps on spinning?! Turn it on again and it goes faster!

You've not understood the point, that's not the same thing, an electric motor has a reference frame, the casing that moves in the opposite direction if only slightly. The EMDrive does not have such a thing. That changes everything!

That means that every time you switch it on, at best the initial speed is the reference frame. That means that every time you switch it on, it must gain the same amount of speed.

That violates conservation of energy.

Also there's a more complicated argument that's even worse.

Consider if the object is moving, and then you stop it with an EMDrive connected to a battery.

Does the battery gain or does it lose energy?

If you can run EMDrive as a dynamo, then the battery gains energy.

OK... but then it all goes bad.

If you look at the same situation from a moving frame of reference, where the EMDrive is initially stationary and then starts moving then the battery must lose energy.

But it's the same battery! Even though moving reference frames have different amounts of energy, you can't have the same battery gain AND lose energy at the same time.

Normal rockets and electric motors have the same problem, but they push off on something, and the books balance if you do the arithmetic carefully, but for EMDrive, they cannot.

Thomas W

Mon Mar 04 2013, 06:06PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
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Posts: 1276

At an atomic level, from what i have learned Energy is the same thing as mass, the equation relating them both is rather commonly known... E = MC^2

Patrick

Mon Mar 04 2013, 07:41PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

there must be a way to measure the forces to extreme accuracy (which affirms its operation), if this mechanism is to be believed. else the conventional expalanation taught and observed countless times, must exclude this device from reality.

Dr. Slack

Mon Mar 04 2013, 08:37PM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

Patrick wrote ...

there must be a way to measure the forces to extreme accuracy (which affirms its operation), if this mechanism is to be believed. else the conventional expalanation taught and observed countless times, must exclude this device from reality.

Unfortunately not. The answer you want is the small difference between two very large quantities. In the original Shawyer experiments, the cavity had thick RF cables and cooling water pipes going to it. You can't measure microNewtons of force (or at least report on them with a straight face) under those conditions. A self-contained power source and cavity would be better, but the energy density of the source then becomes an issue for practical run times. The easiest way to do it would be in orbit (for some definitions of the word easy).

2Spoons

Mon Mar 04 2013, 09:34PM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615

BigBad wrote ...

You've not understood the point, that's not the same thing, an electric motor has a reference frame, the casing that moves in the opposite direction if only slightly. The EMDrive does not have such a thing. That changes everything!

That means that every time you switch it on, at best the initial speed is the reference frame. That means that every time you switch it on, it must gain the same amount of speed.

Your point was not clear from your first post.

Consider then that the 'motive' part of this EM drive is an EM wave. Could this be operating against an absolute reference frame i.e. the universe itself, or however you want to phrase it? I think that would answer all of your objections?

BigBad

Mon Mar 04 2013, 09:49PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600

It was proven by Poincare that you can't use electromagnetism to detect an absolute reference frame, so if it relies on doing this, or enables you to do this, then we can rule it completely out.

Since work is force times distance, if there is an absolute reference frame, then you would have to apply that much work to change the speed.

Since energy is a square law on speed, that would require an extremely large amount of energy to accelerate much, unless you happened to be moving at a speed very close to that of the frame of reference.

But the orbital velocity of the Earth is about 30km/s, so it's difficult to see how you could happen to be moving at the right speed.

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