Rotor RPM

Rotor RPM is the rotational speed of a helicopter’s main rotor, measured in revolutions per minute. It must stay within the approved operating range so the rotor can produce lift efficiently and remain stable. Rotor RPM changes with power, collective input, airspeed, and flight conditions, especially in hover and autorotation. The pilot monitors the RPM gauge and uses throttle, governor, and control inputs as required to keep it in limits.