Conceptual Study on Heat Resistant and Cooling System of Hypersonic Airplanes

Conceptual study of thermo protection structure of the hypersonic aircraft was carried out. Cruising speed of the reference aircraft is Mach 5 at the altitude of 24 km and liquid hydrogen is used as propellant of the engine and vehicle coolant. Precooled turbojet engines and ramjet engines are used as main propulsion system of the aircraft. CFRP is applied to the main structure of the fuselage. Ceramic tiles are glued to the surface of the vehicle to prevent the CFRP structure from high temperature free stream. Liquid hydrogen tanks and cabin are cooled by the liquid hydrogen fuel. Thermal protection and vehicle cooling structure of the reference hypersonic vehicle was carried out in this study. Weight of the ceramic tile is 2.3ton and weight of the vehicle cooling system was 2.4 ton. Furthermore main structure of the vehicle was optimized using Hypersizer program. The lightest structure was 24.7 ton. As a result, total weight of structure and thermal protection became 29.4 ton, whereas that of reference vehicle estimated by MDO study in 2008 was 32.4 ton.