Gyroscopes: Can Two Masses Stabilize?

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    Gyroscopes Two masses
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Discussion Overview

The discussion revolves around the concept of gyroscopes, specifically examining whether two counter-rotating masses on a common spindle can stabilize a system. Participants explore the implications of angular momentum, precession, and the effects of friction on stability, considering both theoretical and practical aspects of gyroscopic motion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether two counter-rotating masses will stabilize or if their angular momentum will cancel out, leading to a fall as if there were no spin.
  • Another participant believes that the system would act as a stable platform, suggesting that the motion of the gyros along a plane provides inertia that helps maintain alignment.
  • Some participants argue that the counter-rotation reinforces stability by canceling out some effects of precession, making the system potentially more stable than two gyros rotating in the same direction.
  • A participant raises a question about the influence of mass distribution, suggesting that if the outer gyro has less mass than the inner gyro, it might balance precession differently.
  • Concerns are expressed about the stresses in the bearings due to counter-rotating gyros, which may affect the overall stability.
  • Another participant mentions that the outer gyro will provide a dominant precession reaction, but its angular momentum will be reduced compared to a normal gyro.

Areas of Agreement / Disagreement

Participants express differing views on the stability of the system, with some asserting that it will be stable while others highlight potential issues with angular momentum and precession. The discussion remains unresolved regarding the overall effectiveness of the proposed gyroscopic system.

Contextual Notes

Participants assume equal mass for the gyros in some arguments, and there is uncertainty regarding the impact of varying mass distributions on precession. The discussion also acknowledges the potential for significant stresses in the bearings, which may complicate the analysis.

Zeinin
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Hey! this is my first post here, and I apologize if it is in the incorrect forum, but I have been banging my head against the wall over this concept and I can't seem to find a straight answer. It concerns gyroscopes.

The question is, can two counter-rotating masses on a common spindle stabilize? or does the angular momentum cancel out, causing the gyro to fall as if it had never been spun at all? Here is an image that might make it more clear:
http://waffleimages.inorpo.com/files/db/db30ce33c1c79796a5c309b88325f37936c1ed5d.jpe
The red and blue rings are the masses in question, and they are attached to the spindle via the yellow ball bearings. They counter-rotate, as evidenced by the green arrows showing the direction of rotation for each mass. Assuming that both rings are spinning at the same rate, and lower point of the frame is placed on a table, what will happen?
There are two possible outcomes here:
1. As the rate of spin drops due to friction, the inclination to precess is canceled out by the opposite rotations, meaning it stays upright until the last possible moment.
2. The two masses cancel each other's angular velocity and the whole assembly falls as it would if there was no spin on the weights.

My hope is that the device will act as traditional one-weight gyro, but with a much greater inclination toward stability. Remember, the spindle/frame is rotationally isolated from the weights. Will it fall, or will be rock steady?
 

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Your link comes up as a forbidden page, and the attachments aren't yet approved, so your answer will have to wait. From the written description, though, I believe that it would be a stable platform.
 
Counter rotating gyros should act as if they aren't spinning, except there are huge stresses in the bearings.
 
Stable platform. The mass in the gyros is in motion, all that motion (for one gyro) is along a plane. This gives the device inertia causing it to tend to stay aligned with that plane. Cuasing the motion of those masses to divert from alignment to that plane requires a force. Since the two planes are parralel to each other, niether gyro is providing a force to divert the other and in fact each is reinforcing the the other. Rotation in oppsite directions means that some or most of the effects of precession will oppose and cancel out, giving a platform that is more stable than two gyros rotating in the same direction.
 
LURCH said:
Stable platform. The mass in the gyros is in motion, all that motion (for one gyro) is along a plane. This gives the device inertia causing it to tend to stay aligned with that plane. Cuasing the motion of those masses to divert from alignment to that plane requires a force. Since the two planes are parralel to each other, niether gyro is providing a force to divert the other and in fact each is reinforcing the the other. Rotation in oppsite directions means that some or most of the effects of precession will oppose and cancel out, giving a platform that is more stable than two gyros rotating in the same direction.
I have a question for you. I've assumed these two gyros are of equal mass. Viewed from above, if the gyro furthest from the point of support tries to precess clockwise, and the other gyro (spinning in the opposite direction) wants to precess counterclockwise, then the sum precession will be clockwise due to the outer gyro having greater leverage.

Is that right so far?

So, if we make the outer gyro of less mass than the inner gyro, is it possible to balance precession?
 
Jeff Reid said:
Counter rotating gyros should act as if they aren't spinning, except there are huge stresses in the bearings.
Now that I see the diagram, the "outer" gyro will provide the dominant precession reaction, but the angular momentum will be greatly reduced compared to a normal gyro.

link videos showing that opposite spin is different than same spin:

http://demoroom.physics.ncsu.edu/html/demos/252.html

So, if we make the outer gyro of less mass than the inner gyro, is it possible to balance precession?
Yes, or the same mass but spinning slower than the inner gyro.
 
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