Research on hypersonic turbojet engine

JAXA successfully attains afterburner combustion for a hypersonic turbojet engine

An afterburner combustion test in progress

The experimental airplane, called the Silent SuperSonic Concept Model (S3CM), is an unmanned supersonic glider with no engine. Its aerodynamic shape is designed based on JAXA's original low-sonic-boom design technology concept. Its total length is 7.913 m, with a 3.510 m wing span, and 4.891 m² wing area. Its total weight is 1000 kg. The rudder and stabilators (differential) are used for flight control. After separation from the balloon, the flight control computer controls all flight sequences autonomously as the aircraft flies over the boom measurement system at designed conditions. The onboard sensors used for flight control are an embedded GPS/INS, an air data system, and a highly accurate Az accelerometer. The main structures are made from aluminum alloy. The manufactured outer shape of the main wing has a jig shape designed so that the deformed shape attributable to the dynamic pressure at the time of measurement of the sonic boom can be formed into the designed aerodynamic shape.

JAXA successfully attained afterburner combustion for a hypersonic pre-cooled turbojet engine under Mach-4 flight conditions. The experiment was conducted in a propulsion wind tunnel (at Kakuda Space Center in Miyagi Prefecture) from February to March 2016. An afterburner injects fuel into the exhaust stream of a jet engine, triggering high-temperature combustion that creates an increase in thrust. JAXA's experiments showed that the liquid hydrogen fuel supplied to the engine had an air pre-cooling effect and also a combustion capability at a high temperature (2,000 Kelvins) when the afterburner was active.

JAXA is planning to make adjustments to the intake and core engine operations in hopes of increasing overall thrust.

April 21, 2016

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