An apparatus and method for detecting an impact on a rotor blade

摘要

A gas turbine engine (10) comprises a fan rotor (26) having a plurality of fan blades (24) and an apparatus (34) for detecting an impact on the fan blades (24). The apparatus (34) comprises speed sensors (48,48B) arranged to measure the speed of rotation of the fan rotor (26) and the turbine rotor (58) and to produce speed signals. A processor unit (40) analyses the speed signals to determine the angle of twist between the ends of the fan rotor (26). The processor unit (40) is arranged to analyse the angle of twist to determine if the angle of twist of the fan rotor (40) oscillates by more than a predetermined level from an average level. The processor unit (40) is arranged to produce a signal indicative of an impact to at least one of the fan blades (24) if the angle of twist oscillates by more than the predetermined level and sends a signal to an indicator device (44,46). <IMAGE>