Secondary Power System Options for Future Military Aircraft

This paper summarizes a recent study for twin-engine military transport aircraft. Five major system arrangements plus a number of variations were analyzed. Power sources and drive equipment included: the main engines, engine-mounted accessory gearboxes, airframe-mounted accessory drive gearboxes, electrical batteries, auxiliary power units, air-turbine motors, ram air turbines, monopropellant emergency power units, bipropellant emergency power units, and various integrated power units which can be operated in two or more modes. The comparative impact of these system arrangements on aircraft weight, range, and life-cycle cost are shown.