Concept study of flying test bed for hypersonic airbreathing engines

Abstract

In Japan, National Aerospace Laboratory of Japan (NAL) has initiated to study the spaceplane concept and develop the required hypersonic technology bases since 1987. The primary purpose of the spaceplane program is to provide technology as well as base research and development capabilities in critical disciplines for the future development of manned space transportation systems. Hypersonic airbreathing propulsion systems that should be applied for future space transportation systems are urgent developmental subject. The realization of spaceplane systems is depending on airbreathing propulsion system performance. Basic concepts of the Flying Test Bed (FTB) that are studied at the National Aerospace Laboratory (NAL) are unmanned, autonomously controlled, self-accelerating to hypersonic region and reusable vehicles. Hypersonic airbreathing test engines to be installed on the FTB have not yet confirmed its reliability during previous ground tests. Therefore, the FTB must maintain sufficient stability margin even in case of test engine's malfunction including sudden stop. Two turbo-jet engines for take-off, fly-back cruse and landing and one rocket engine for accelerating to hypersonic region are installed in the FTB. Three propellants that are kerosene for jet engines and rocket engine fuel, liquid oxygen for rocket engine oxidizer and liquid hydrogen for test engine fuel are *1 National Aerospace Laboratory of Japan, 7-44-1 Jindaiji-Higashi, Chofu, Tokyo, 182-8522, Japan Copyright©2001 by the American Institute of Aeronautics and Astronautics, Inc. All right reserved. installed in the FTB fuselage. Kerosene tanks are separated into two tanks to control vehicle center of gravity by kerosene transfer. The FTB has a acceleration capability of up to flight MACH number of 6. The FTB will horizontally take-off by jet engines, and accelerate to flight Mach number of 6 by a rocket engine. The FTB will turn to launch site direction without engine thrust and glide-back to launch site and horizontally land. This paper describes the FTB system analysis results that include vehicle sizing analysis and flight analysis by NAL.