U.S. Patent Specifications

A starter system for an aircraft gas‐turbine engine comprising a starter motor and a gear mechanism connected between the starter motor and the engine whereby during starting the motor drives a turbine/compressor rotor assembly of the engine, which gear mechanism comprises a first gear train giving a first ratio of motor rotational speed to rotor assembly rotational speed suitable for starting under normal ground conditions and a second gear train giving a second ratio less than the first ratio and suitable for starting the engine in flight, and means for selecting the desired gear train.