The USA has revived plans to develop technology for a hypersonic strike missile. Flight testing is planned to begin next year under the Defense Advanced Research Projects Agency's (DARPA) Hypersonic Flight (HyFly) programme, a follow up to its cancelled Affordable Rapid Response Missile Demonstrator (ARRMD).
Under the DARPA/US Air Force ARRMD programme, Boeing Phantom Works was developing technology for a Mach 6.5, 400nm range, 2,500lb-class (1,135kg-class) air-breathing missile. The DARPA/US Navy HyFly programme aims to demonstrate a 324km (600nm) range vehicle with an average speed above M4, a maximum sustainable speed exceeding M6, and the ability to dispense a simulated submunition.
Work on ARRMD was halted after delays in developing the Pratt & Whitney HyTech hydrocarbon-fuelled supersonic-combustion ramjet (scramjet) engine for the chosen waverider missile, says Phantom Works president George Meullner. "They could not sustain combustion. It was a test cell issue and Pratt & Whitney fixed it, but DARPA pulled the plug.
The HyFly programme, Muellner says, will involve the Aerojet dual-combustion ramjet/scramjet engine evaluated for ARRMD, but rejected in favour of the HyTech scramjet. This results in a missile with a more conventional circular cross-section. DARPA's plans call for freejet engine testing this year, followed next year by ground tests of a flight-weight engine, a drop test of the integrated vehicle and booster separation flight test, and short-duration flight testing.
Flight tests will be initiated as early as possible and will increase in difficulty and risk as they progress. DARPA has yet to announce a contractor for HyFly, but Muellner suggests the Phantom Works will receive the contract based on its work on ARRMD.
Source: Flight International