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27 November 2024 12:59
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Question |
| Asked by: |
Jerry Volland |
| Subject: |
Does Precession Occur In Non-Gyroscopic Systems? |
| Question: |
Does precession occur in non-gyroscopic systems? For example, does the planar movement of an accelerating flywheel attached to a swing arm constitute precession?
http://www.spaceoffice.us/ipm.htm
Jerry |
| Date: |
6 May 2006
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Answers (Ordered by Date)
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| Answer: |
Jerry Volland - 06/05/2006 12:40:48
| | | Also, will tipping a half-wheel gyro at the right time produce precession?
Jerry
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| Answer: |
Glenn Hawkins - 06/05/2006 13:46:50
| | | Hello Jerry, Jerry quite contrary,
If the swing arm is absolutely, directly overhead and the swing action is absolutely aliened in the same direction of rotation all that happens is pendulum action. If however it keeps swing long enough I believe with less certainty that the disk will find a way to gradually come out of alignment. Then of course you’d have tinny processional effects alternating clockwise then counter clockwise as the pendulum swings forward then rearward.
If the swing arm were offset then it’d attempt to precess right, then left depending on forward swing then rearward swing.
This is an interesting question you ask, “tipping a half-wheel gyro at the right time.” If you ever test it let us know. You’re going to have a mess that should be difficult to sort out. I believe the gyro would twist left or right depending on whether the half-wheel were up or down when tilted. Also the contraption would move sideways left, or right depending again on whether tilt occurred when the full half was up, or down. I’d like to know the answer from a real test and hear any ideas of how this may, or may not be of any use.
Glenn,
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| Answer: |
Sandy Kidd - 09/05/2006 13:20:03
| | | Jerry,
There is no difference between what we call a gyroscope and a flywheel (which a gyroscope in effect is)
I see a gyroscope as a device which is accelerated only by the force of gravity, and is consequently subject to nutation and precession.
What you are describing here is in effect what we tend to call an accelerated system and as such is not subjected to nutation or precession.
If you accelerate your flywheel it will rotate just below the horizontal under (no apologies for using centrifugal acceleration) here, until it is accelerated fast enough to generate enough torque, to accelerate inwards towards its axis of system rotation.
This is not precession which is normally seen in a decaying system.
It’s quite a bit more involved than this but in effect the outcome is similar to passive or gravity accelerated systems, in as much as no angular momentum will be detected and no centrifugal force will be found to be present either, in essence the same as a passive or gravity accelerated gyroscope in precession, just rotating considerably faster.
It can be seen that there is no precession as such in an accelerated system, which this is, and using the word precession with regard to accelerated systems is wrong and can be very misleading.
Hope this helps.
Sandy.
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| Answer: |
Jerry Volland - 21/05/2006 12:03:39
| | | Glenn,
Yes, I agree that an offset pendulum arm would result in some precession, since this would in effect be swinging a gyro. However, with the setup I described, the increasing speed of rotation is what causes the pendulum action - at least after the acceleration stops. (Why?) Also, I haven't tested a half wheel, but I have tipped a 1/10 wheel, which is just a rotating weight. This produces forwards movement.
Sandy,
I agree that this is an accelerated system; the rotational speed of the flywheel increases, and the mass of the flywheel is accelerated by being pulled into a curve. I also accept your conclusion that precession would be absent, for the most part, in such a situation. What I'm trying to understand is why the centrifuge force also vanishes with a weighted spoke when the shaft is accelerated to the side by a spring. With all the mass on one side, there aren't any opposing reactions to cancel out.
Jerry
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