Aerojet has completed Mach 6 ground testing of a flightweight combustor for its dual-combustion ramjet, clearing the way for flight tests of the HyFly hypersonic missile technology demonstrator.
The company has already delivered two dual-combustion ramjets to Boeing and the HyFly is expected to be tested shortly, under the US Defense Advanced Research Projects Agency/Office of Naval Research programme.
The dual-combustion ramjet comprises a ramjet that burns liquid fuel in a subsonic ramjet to generate a fuel-rich gas that is burned in a supersonic-combustion ramjet. The entire engine is made of a lightweight high-temperature ceramic matrix composite.
HyFly is intended to demonstrate a missile configuration with 740km (400nm) range and a cruise speed exceeding M6 after launch from a Boeing F-15E. Two launches were conducted in 2005 to verify separation and booster operation, but testing of the dual-combustion ramjet-powered vehicles was delayed by design changes.
The US Department of Defense is conducting an analysis of alternatives for a high-speed strike weapon, with options including missiles based on HyFly, the scramjet-powered Boeing X-51A and Lockheed Martin's high-Mach turbine-powered RATTLRS.