Japan has picked a pre-cooled turbojet as the core of the ATREX expander-cycle air turbo ramjet under research for potential application in the air-breathing flyback booster of a future two-stage-to-orbit (TSTO) spaceplane. Using a pre-cooled turbojet would increase the payload fraction of the TSTO vehicle to over 40%, says IHI Aerospace.
After studying a range of configurations, IHI selected an engine with a four-stage fan and a bypass duct after the fan. Other configurations studied ranged from an engine with eight-stage compressor and no bypass to a design with extra boost stages between fan and bypass duct.
Bypass flow increases turbine efficiency and reduces Mach number at turbine exit, and the four-stage fan with bypass design is the easiest to develop, says IHI. The Japan Aerospace Exploration Agency plans to run a series of ground-test engines at speeds up to Mach 6 over the next three years, potentially leading to flight tests before 2010.
Source: Flight International
