Advanced technology payoffs for future small propulsion systems

Abstract

The objectives of the NASA/Army-sponsored Small Engine Component Technology (SECT) study were to identify high-payoff technologies for year-2000 small gas turbine applications and to formulate the required technology programs. The projected technologies were evaluated in terms of their influence on operating cost for the four candidate applications: rotorcraft, commuter, cruise missile, and auxiliary power unit (APU). This paper reviews the reference missions, engines, and aircraft, the year-2000 technology projections, cycle studies, advanced engine selections, and technology evaluations. Conventional simple cycles and heat-recovery cycles were both evaluated. The resulting direct operating costs (DOC) were nearly equal for simple and heat-recovery engines at low fuel prices ($l/gal). Heat-recovery engines clearly were advantageous at high fuel prices ($2/gal). System DOC improvements ranged from 6 to 11 % for the rotorcraft and the commuter application. Reductions in engine DOC for the APU ranged from 37 to 41%. Missile cost per mile was reduced by nearly 80%, relative to today's rocket-powered system, and by 50% over a near-term turbojet propulsion system. The high-payoff technologies identified include ceramic materials for the rotorcraft, commuter, and APU engines and carboncarbon (C-C) materials and boron slurry fuel for cruise missiles.