The Langley Research Center maintained an active hypersonic research program from the early days of the formation of NASA in 1958. The goals of the Hypersonic Research Engine (HRE) project, which began in 1964, were to design, develop, and construct a ramjet/scramjet for flight test from Mach 4 to 8. The flight test goal was lost when the X-15 aircraft program was cancelled in 1968. Ground tests of full scale models then became the project focus with structural cooling tests in the NASA Langley 8-Foot High Temperature Structures Tunnel, and internal thrust performance tests in the NASA Lewis Plum Brook Hypersonic Test Facility (HTF).

Tests were conducted in the HTF at Mach 5, 6, and 7 with this gaseous hydrogen fueled, water-cooled, boiler-plate Aerothermo-dynamic Integration Model. Parameters investigated included fuel/air ratio, angle of attack, and various simulated altitudes and inlet contraction ratios. Good ramjet/scramjet engine performance was obtained over the tested Mach number range.