JAPHAR: A joint ONERA/DLR research project on high speed airbreathing propulsion

An overview is presented of progress achieved by JAPHAR (Joint Airbreathing Propulsion for Hypersonic Application Research), which was designed to further knowlege of scramjet technology, specifically, dual mode ramjet (DMR) technology. Consideration is given to JAPHAR efforts to define a DMR combustion chamber that could operate successfully in subsonic and supersonic combustion, the benefit of the latter occurring around Mach 6.5. One way to meet requirements, without using variable geometry, is to design a double combustion chamber, with different levels of injection that allow the combustion process to be located at different places depending on the flight Mach number. DMR injection system development efforts and fundamental research on supersonic combustion are also described, and aerodynamic components of the propulsion system are investigated.