A gyroscope is a rotating body that is mounted in such a way that it is free to turn about any of three mutually perpendicular axes. If the wheel spins with high angular speed about the innermost axis, the base may be turned in any manner without transmitting a torque, except for frictional torque, to the rotating wheel, which will therefore maintain its axis of rotation unchanged as the support is tilted in any manner so long as the wheel rotates of a rapidly. Since the angular momentum depends upon the moment of inertia and upon the angular velocity, a heavy wheel rotating at high speed would have large angular momentum and correspondingly great stability. If a torque is applied perpendicular to the axis of spin, there will be precession of the axis.
Two principal characteristics of the behavior of gyroscopes are (1) stability of the axis and (2) precession. Both these characteristics are employed in the many applications of gyroscopes. In those applications which require stability great care must be taken in mounting the gyroscope wheel so that as little torque as possible is transmitted to the axis. In this class of application are the gyropilot, gyrohorizon indicator, directional gyro and to some extent the gyrocompass. The latter, however, is constructed such that when it is in any position except that with its axis parallel to the axis of the earth, there will be a torque which will cause precession into that position. For rotating bodies that show gyroscopic action, the greater the angular momentum, the more marked will be the effect. Some of these effects are useful, others harmful. As a car turns a corner, the gyroscopic action of the wheels produces a torque tending to overturn the car. If the flywheel rotates counterclockwise as one looks forward in a car, the force on the front 25 wheels decrease when the car turns to the right but increases when the car turns to the left.
Posted 2011-01-29 and updated on Jan 29, 2011 8:42pm by crisd