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The most important question that should have been top center: with reactionless propulsion it is possible to create a free energy device. Attach the thruster t

The most important question that should have been top center: with reactionless propulsion it is possible to create a free energy device. Attach the thruster to a wheel. When the thruster is firing, it consumes constant power and the wheel accelerates, spinning ever faster. The wheel can be attached to a generator that produces power which is thrust times the rim velocity. Thus, after a certain speed, the wheel produces more power than the thruster consumes. This was discussed on a rocketry list.

bellerocky 12y ago
And where would the "free energy" be coming from? Pretty sure you'd be losing energy, as energy doesn't come from thin air.
VikingCoder 12y ago
At least one of the theories on the article talked about pushing on virtual particles, like a submarine pushing on the water around it. This would imply to me that efficiency goes down with speed. Just a thought.
- Gravityloss 12y ago
  But there is a problem with that, that there should be some kind of aether of virtual particles that would have small velocity compared to the thruster. Yet there is little evidence so far for such a thing. http://en.wikipedia.org/wiki/Aether_theories http://en.wikipedia.org/wiki/Aether_theories
ghshephard 12y ago
I"m not following why you think the wheel generator will produce more power than is required to spin the wheel in the first place. Friction is a pretty big issue in your scenario. It seems orthogonal to the actual results.
- Gravityloss 12y ago
  The whole thing was a thought experiment to show how extraordinary the supposed result is. Power of the wheel = thrust * rim velocity. That's just basic physics you should learn in high school. P_1 = F * v This means if your force, that is, thrust, is constant, you generate more power the faster you go. That's also why cars accelerate faster from 20 to 30 km/h than from 120 to 130 km/h - they have constant power which means they have more force at lower speeds and thus higher acceleration at lower speeds. The claimed thruster produces a constant thrust for a certain power, let's use a factor k for that: P_2 = k * F Now if we want perpetual motion, we can set P_1 = P_2, and solve F * v = k * F v = k If we let the speed be faster, we can actually generate power from the wheel in excess of what the thruster uses. We can also have some friction, let's say the wheel generator is 50% efficient. We then need to run the wheel twice as fast to get the same effect. There actually exists a trivial "reactionless" thruster if we use a flashlight and the light pressure. But it turns out the velocity is the speed of light then.
  - gus_massa 12y ago
    I totally misinterpret your first comment. It looks like "This is even more amazing! We have a perpetual mobile machine!!" but it's really is "This also break the energy conservation law! So we have a serious problem." In special relativity, momentum and energy are much related, so if you break the conservation of one of them, you break also the conservation of the other. (It's not very clear if the authors say that this device break the momentum conservation, all the information is very confusing.) But the example is nice. Just get two of these devices and put them in the opposite sides of a carrousel or a spinning space station so you don't have to worry about friction.
    - Gravityloss 12y ago
      Thanks for the comment, now I realize the post was not very well written in that regard. It is hard to express these contradicting ideas in a small space: 1. If this works, forget spacecraft. Free energy for everyone! 2. I think it's a measurement error. There are other reasons to think so as well, a person said that the "out there" advanced space propulsion research community traditionally gives a lot more leeway than some other research disciplines where this might have come up.

bellerocky 12y ago

And where would the "free energy" be coming from? Pretty sure you'd be losing energy, as energy doesn't come from thin air.

VikingCoder 12y ago

At least one of the theories on the article talked about pushing on virtual particles, like a submarine pushing on the water around it. This would imply to me that efficiency goes down with speed. Just a thought.

Gravityloss 12y ago
But there is a problem with that, that there should be some kind of aether of virtual particles that would have small velocity compared to the thruster. Yet there is little evidence so far for such a thing. http://en.wikipedia.org/wiki/Aether_theories http://en.wikipedia.org/wiki/Aether_theories

ghshephard 12y ago

I"m not following why you think the wheel generator will produce more power than is required to spin the wheel in the first place. Friction is a pretty big issue in your scenario. It seems orthogonal to the actual results.

Gravityloss 12y ago
The whole thing was a thought experiment to show how extraordinary the supposed result is. Power of the wheel = thrust * rim velocity. That's just basic physics you should learn in high school. P_1 = F * v This means if your force, that is, thrust, is constant, you generate more power the faster you go. That's also why cars accelerate faster from 20 to 30 km/h than from 120 to 130 km/h - they have constant power which means they have more force at lower speeds and thus higher acceleration at lower speeds. The claimed thruster produces a constant thrust for a certain power, let's use a factor k for that: P_2 = k * F Now if we want perpetual motion, we can set P_1 = P_2, and solve F * v = k * F v = k If we let the speed be faster, we can actually generate power from the wheel in excess of what the thruster uses. We can also have some friction, let's say the wheel generator is 50% efficient. We then need to run the wheel twice as fast to get the same effect. There actually exists a trivial "reactionless" thruster if we use a flashlight and the light pressure. But it turns out the velocity is the speed of light then.
- gus_massa 12y ago
  I totally misinterpret your first comment. It looks like "This is even more amazing! We have a perpetual mobile machine!!" but it's really is "This also break the energy conservation law! So we have a serious problem." In special relativity, momentum and energy are much related, so if you break the conservation of one of them, you break also the conservation of the other. (It's not very clear if the authors say that this device break the momentum conservation, all the information is very confusing.) But the example is nice. Just get two of these devices and put them in the opposite sides of a carrousel or a spinning space station so you don't have to worry about friction.
  - Gravityloss 12y ago
    Thanks for the comment, now I realize the post was not very well written in that regard. It is hard to express these contradicting ideas in a small space: 1. If this works, forget spacecraft. Free energy for everyone! 2. I think it's a measurement error. There are other reasons to think so as well, a person said that the "out there" advanced space propulsion research community traditionally gives a lot more leeway than some other research disciplines where this might have come up.