Development study on ATREX engine

This is the status report of the development study on ATREX engine (Air Turbo Ramjet) that is now under way in the Institute of Space and Astronautical Science (ISAS) in cooperation with the Ishikawajima Harima Heavy Industries (IHI). the Kawasaki Heavy Industries (KHI). the Mitsubishi Heavy Industries (MHI) and the Daimler-Benz Aerospace AG (DASA). ATREX engine will be applied for the propulsion system of fly-back booster of TSTO space plane’. ATREX is the fan-boosted ramjet producing the effective thrust from sea level static to flight Mach number 6. ATREX is worked on the expander cycle with three heat exchangers of hydrogen fuel, that is, the precooler, the internal heat exchanger and the regeneratively cooled combustor as shown in Fig.1. ATREX employs the tip turbine configuration which allows compactness and light weight of turbo machinery and the variable geometry airintake and plug nozzle which allows to operate under the wide range flight conditions. ATREX development study has been conducted with the sea level static tests since 1990. ATREX engine tested is the scaled model designated by “ATREX-500” of which fan inlet diameter is 300 mm and overall length 2.200 mm. From 1992 have been performed the wind tunnel tests on the primary aerodynamic components such as the axisynunetric variable geometry air intakes, the variable geometry plug nozzles and the flying test bench with ATREX model. The application study on advanced carbon-carbon composite for the tip- turbine and fan assembly has been conducted². The flight test of ATREX is now planning in order to verify the engine performance and functions in the practical flight conditions by using an unmanned flying test bench. In 1995 and 1996 was tested ATREX-500 installing two type of precooler and the regeneratively cooled combustor under the sea level static conditions to examine the engine performance and the icing problem on the precooler. The present paper addresses the test results of precooled ATREX-500 engine.