Geared turbofan with four star/planetary gear reduction

摘要

A gas turbine engine has a fan rotor, a turbine rotor driving the fan rotor, and an epicyclic gear reduction positioned between the fan rotor and the turbine rotor. The epicyclic gear reduction includes a ring gear, a sun gear, and no more than four intermediate gears that engage the sun gear and the ring gear. The fan drive turbine is configured to drive the sun gear to, in turn, drive the ring gears to, in turn, drive the fan rotor.