Energy Sink

[philip]

Can anyone tell me, if energy is neither created or destroyed (they say), where does the energy go when torque is applied to forcibly precess a gyroscope. When torque is stopped the gyroscope will stop precessing though the angular velocity of spinning gyroscope does not alter if good bearings are used, no energy is lost or gained here. Neither does heat appear or disappear anywhere in/on the gyro/gyro shaft, again assuming good bearings are used. I could install some kind of high rpm gyro on a motor shaft, with an axis perpendicular to the motor shaft, power it up and have loads of energy output from the motor just, disappear (not that this is the purpose of this site to determine ways to make energy disappear).  Or have I missed something

Phil

are you sure the gyro wheel would not heat up?

I'm certain that no heat appears in the gyro itself (and this would be an interesting effect in itself if it did). In the bearings there would be small losses from friction but very small in comparison to the energy that can be input.

Phil

[philip]

Probably this,the images, gives some inspiration:

http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=JP56029066&F=0
GO TO "Original document"

S
  dL

Thanks
Looks similar to one of Schauberger's turbines and an engine by Richard Clem at http://www.rexresearch.com/clemengn/clemengn.htm. Definitely onto something.
Phil

[tinu]

Very interesting question, indeed. It took me some time to figure it out but imo the answer is quite simple at the end.

First, let?s take the bicycle wheel example, as it is better&simpler. The wheel will stop due to friction because the articulation does not allow 2-axis rotation. So, once you try rotating the fork in horizontal plane, angular momentum conservation would tend to rotate it also in a third plane (a vertical one, perpendicular to the wheel axis) but this movement is not allowed due to the mechanical setup. Hence, the energy is lost in friction. (And no ideal bearing exist for this case).
However, if you replace the articulation with one having 3-dimensions freedom degree, by applying a torque in horizontal plane, a precession movement will be seen. Nothing new here, as this issue was raised in the first place, in the very first post.

The question is: why do you think that the precession movement will stop once the external torque is removed? Because, imo it will not. Try for yourself with a ball (a large one, preferably a basketball). It is possible to superpose as many rotation components as you wish. They will not cease once you apply the external torque, although they may be affected (may be composed) in a way similar to the precession movement you see for a gyroscope. Hence, the external energy does not disappear but it is stored as an angular momentum on a particular rotation axis. If a kind of regenerative brake is applied, one can recover the energy spent in the first place. Agree?

[philip]

Very interesting question, indeed. It took me some time to figure it out but imo the answer is quite simple at the end.

First, let?s take the bicycle wheel example, as it is better&simpler. The wheel will stop due to friction because the articulation does not allow 2-axis rotation. So, once you try rotating the fork in horizontal plane, angular momentum conservation would tend to rotate it also in a third plane (a vertical one, perpendicular to the wheel axis) but this movement is not allowed due to the mechanical setup. Hence, the energy is lost in friction. (And no ideal bearing exist for this case).
However, if you replace the articulation with one having 3-dimensions freedom degree, by applying a torque in horizontal plane, a precession movement will be seen. Nothing new here, as this issue was raised in the first place, in the very first post.

The question is: why do you think that the precession movement will stop once the external torque is removed? Because, imo it will not. Try for yourself with a ball (a large one, preferably a basketball). It is possible to superpose as many rotation components as you wish. They will not cease once you apply the external torque, although they may be affected (may be composed) in a way similar to the precession movement you see for a gyroscope. Hence, the external energy does not disappear but it is stored as an angular momentum on a particular rotation axis. If a kind of regenerative brake is applied, one can recover the energy spent in the first place. Agree?

True, in a system free to move in three dimensions the wheel will simply reflect this torque around another axis at right angles to which it was applied (eg if torque is applied around an x axis it would reflect around the y axis). And if the system was free to move in all dimensions there would little resistance by the wheel/gyro to being rotated.

But for this example I will stay with the mechanical setup I have described, with the rotating fork in, say, a horizontal plane (as in the diagram) that resists any rotation into another plane. The wheel will try to move into some other plane at right angles to the wheel axis but is resisted by the vertical fork which opposes this rotation with an equal and opposite torque. And it is this equal and opposite torque reflected back to the horizontal plane that is the resistance we feel when we try to rotate the wheel.
(the amount of torque will depend on the rpm of the wheel and the rate at which it is rotated around the vertical axis).

If we applied torque and rotated the spinning wheel on the forks around the horizontal plane (as in the diagram) the moment we let go the rotation of the wheel around the vertical axis would slow at a rate determined by the rpm of the wheel and the moment of inertia of the system around the vertical axis.

eg If a very light aluminium wheel was spun at say 20000 rpm (without exploding) this would be very difficult to rotate around the vertical axis of the forks. A large amount of torque (work) would be required and the second I let go the rotation of wheel around the vertical axis would stop dead. The work that I have applied could not have just disappeared into the bearings. Yet the same aluminium wheel spun at 0 rpm having been rotated around the vertical axis would spin freely.

[tinu]

Thanks for replying, Phil.
I?m having some difficulties with my English but I could hopefully follow your entire message.

There is one point I do not agree and imo it would be pointless to discuss further before making it clear. I have to firstly say that I do not have practical experience with gyros and my reasons are mostly logic and mainstream science based. No offense pls. I?m just expressing my thoughts and I admit that I may be wrong.

You say that ?if the system was free to move in all dimensions there would little resistance by the [wheel]??. I have to strongly disagree with ?little resistance?. Resistance can and it actually will be very high if the angular momentum is high enough, even if the wheel is free to move in all dimensions! The wheel is not important here. Let?s replace it with the ?Earth?. The Earth, Moon, Sun etc are free to move in all three dimensions. And yet, they oppose a huge resistance. (It is well known that rotation axis of planets are very stable. That?s why North Star is always there, in the same spot on the sky). Ok, one will ironically say that this is just because planets and stars have a huge mass. Not really, I would reply. It is not because they have huge mass but because they have a huge angular momentum. A light wheel rotating at a huge speed will have an insignificant rest mass but it will have a very high angular momentum and it will behave kind of ?like a planet? in respect to the resistance opposed when one tries to change its rotation axis. Therefore, when you later on say that ?eg If a very light aluminium wheel was spun at say 20000 rpm (without exploding) this would be very difficult to rotate around the vertical axis of the forks? I would reply that you are right, of course, but the forks have nothing to do with it and they can be completely disregarded. Hopefully I made my idea clear, but then I?m having problems understanding why do you want to keep the forks in the setup?

Let?s clear the above little step. Ok?