Machinery's hanbook doesn't say, and the formulas I've found on the web are too far beyond my understanding. My goal is to determine how much resistance a particular flywheel, at a particular speed, has to being twisted around an axis perpendicular to the axis of rotation. Thank You, Eric R Snow
Eric, Take a look at
Thanks Fred, it looks like the answers just might be there. Eric
Good site.
The confusing thing about gyroscopes is that reaction torque in one axis is proportional to angular rate in the other axis, both axes being orthogonal to the spin axis. If there is no rate on axis 1 then there is no gyrodynamic torque on axis 2, and conversely.
The "and conversely" is the confusing part. Gyro torque on axis 2 from rate on axis 1 must produce rate on axis 2 to result in a countertorque on axis 1 to impede it's rotation. Dizzy yet?
In your flywheel example, let's say your flywheel axel is horizontal and the machine is mounted on a horizontal turntable. If the turntable and its bearings were rigid enough to permit absolutely no deflecton from horizontal, then you could spin that turntable as easily as if the flywheel weren't spinning because there would be no countertorque resisting table motion, though there might be bolt-ripping torque on the table bearing trying to twist the table so the flywheel axis could nod up or down.
If the flywheel axis is free to rock up and down and there is lots of angular momentum in the flywheel, this system could be very stiff to turntable rotation because "rocking" angular rate is possible to produce countertorque in response to table rotation rate. Stiill, if there is no angular rate there is no torque. The sneaky thing about gyros is that very small angular rates about one axis can produce very large torques about another axis. .
Steady torque on the table would result in a steady rocking rotaton rate, however small, that would eventually "tumble" the gyro. .
I'm not making this stuff up. I worked in an aerospace gyro lab nearly 40 years ago.
There are some interesting effects if you try to walk while carrying a large gyro spun up to speed. If you try to change direction the gyro will exert considerable resistance and refuse to change in the desired direction while at the same time obstinately swinging out about its horizontal axis. If you are not expecting to this, its apparently impossible behaviour can be quite disturbing.
With experience it's quite easy to apparently naturally carry a spun up gyro. You steer it by applying the appropriate force about the horizontal axis to to persuade it to change its direction about the vertical axis.
Some of the larger gyros were very quiet and would take a very long time to spin down once power was removed. A favorite trick was to put one of these in a suitcase and give it to a hotel porter to carry through a revolving door!
Jim
Oh man thats cold.
Really cool..but cold man..cold. I love it!
Gunner
Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry
This was the standard film in the physics class. The showed the hidden camera filming an MIT student who is given a suitcase to carry down a hallway. A hallway with a
90 degree turn....Hilarious.
Jim
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