Rigidity in space and precession are two main properties of a gyroscope. These properties are the basic principle of operation behind many attitude, heading, and inertial reference systems found in aircraft.

Consider a gyroscope with its mass rotating about a given axis. If a force is applied on the rotating mass in its plane of rotation, the force will induce a torque about an axis situated 90° to its plane of rotation. Because the gyro’s mass is rotating, this force will be applied at a right angle to the gyroscope’s rotational axis. This is called gyroscopic precession.

Rigidity determines how prone is the gyro to process torque on its spin axis as the airframe is displaced. This is the law of conservation of angular momentum. Concentrating the gyroscope’s mass at its periphery will give the instrument more stability which ultimately will improve its rigidity in space.