Advanced propulsion developer Reaction Engines is nearing its first step toward validating its novel air-breathing hybrid rocket design at hypersonic conditions by firing up a vintage General Electric J79 turbojet to act as a heat source for testing, expected later this month. The ex-military engine, formerly used in a McDonnell Douglas F-4, is a central element of Reaction’s specially developed high-temperature airflow test site, which will soon be commissioned at Front Range ...