Re: Decent Gyro chips?

Sjouke Burry wrote:

Foucault's pendulum precesses because the earth's rotation exerts a torque on the pendulum by moving its mounting point. A Foucault pendulum has to follow the earth, but a gimballed gyro doesn't, so it doesn't exhibit the precession.

Oh yes it does. I modified a big giro from an airplane,
an on balancing(any imbalance causes it to drift) ,
i could not stop it from moving.
Until i found out i was measuring earth rotation.
To my surprise it was quite accurate !!
360 degr/day, 15 degr/hour,15arcmin/minute.

That isn't precession, it's just the rotation of the Earth. The distinction is that when something precesses, its axis moves with respect to an inertial frame, due to an applied torque component perpendicular to the rotation axis. Your gyro's rotation axis was merely remaining stable in an inertial frame--yet another successful test of the law of conservation of angular momentum. Precession is what spinning tops do when they aren't supported at their centre of mass.

Take a wheel of a bicycle, and spin it while holding it up vertically by one end of the axle. It will precess due to the torque of its weight acting on half the length of its axle. If you hold both ends, it doesn't precess because there's no torque applied. Torque applied along the rotation axis also doesn't cause precession--it just changes the rotation rate.

Cheers,

Phil Hobbs
.

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