Plain English Meaning

A fast-spinning wheel does two useful things: it tries to keep pointing the same way no matter how the aircraft moves around it, and when something pushes on it, it reacts in a sideways, delayed way. Flight instruments like the attitude indicator, heading indicator, and turn coordinator are built around these two behaviours.

Full Definition

The two physical properties of a spinning rotor that make gyroscopic flight instruments work: rigidity in space (the spinning rotor resists changes to the direction its spin axis is pointing) and precession (when an outside force is applied to the rotor, the resulting movement shows up about 90 degrees around the rotor in the direction of spin, rather than where the force was applied).

Context Anchor

Seen when learning how gyroscopic flight instruments work, especially instruments that show , direction, or .