Rapid thrust response control logic for shaft-driven lift fan STOVL engine

摘要

A short take-off and vertical landing (“STOVL”) aircraft has a conventional gas turbine engine that is selectively mechanically connected to a vertically-oriented lift fan by a drive shaft when the aircraft operates in a vertical flight mode. An engine control provides for rapid response thrust control of the lift fan and low rotor spool when the pilot initiates desired changes in thrust. The control achieves the rapid thrust response by varying the inlet guide vanes of the lift fan, together with selective fuel flow scheduling. These variations result in a substantially constant low rotor speed, which facilitates the desired rapid thrust response and corresponding aircraft control.