Abstract: A gas turbine engine drive for a marine propeller having a forward and reverse drive transmission having controls operative during engine operation in a braking neutral position to decrease engine inertia and to brake the input and engine and also the output and propeller prior to shifting to either a forward or reverse drive to reduce shift shock, and a positive neutral position to positively disconnect the input and output so the engine can drive accessories without driving the output and propeller, and operative when the engine is not operating to brake the input and engine and also the output and propeller. In another control, the reverse drive signal decreases engine inertia in braking neutral.

Abstract: A power train having a gas turbine engine with controlled power transfer between the load turbine drive train and the compressor turbine drive train and a power shift transmission is shown. The engine control system includes a fuel control responsive to input and output speeds and compressor discharge pressure and an output power characteristic, horse power and torque, program control responsive to compressor and auxiliary torque and speed controlling the power transfer clutch between the compressor and engine to maintain proper turbine inlet temperature at a proper constant high value in a wide range of operation for optimum efficiency. Overcontrols responsive to acceleration and the temperature of the power transfer clutch and ambient air are provided. The power shift transmission control pressure is controlled by compressor discharge pressure and engine output or transmission input speed to provide a shift actuating pressure proportional to the torque produced by the engine.