Abstract: Clearance control means is provided for a gas turbine engine. In one embodiment relating to compressor blade clearance, means is provided for developing a first signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Schedule means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal. The schedule output signal is representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. Means is provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control signal representative of the difference therebetween.

Abstract: An integrated control system for a gas turbine engine of the turbofan type receives signals from a plurality of engine sensors and from the engine operator and generates control signals therefrom. A first control signal regulates the fan exhaust nozzle area in order to control inlet throat Mach number to maintain a low level of engine noise. Additional control signals regulate fuel flow to control engine thrust and fan pitch to control fan speed. A plurality of schedules are utilized to maintain a predetermined relationship between the controlled parameters and a number of fixed and calculated limits can override the control signals to prevent unsatisfactory engine performance.