Ramjet for long-range missile succeeds in windtunnel
Aerojet has successfully completed a series of high-speed windtunnel tests of a hypersonic dual combustion ramjet (DCR) that will power the US Navy's planned Mach 6 HyFly long-range strike missile.
The Sacramento, California-based company is developing the engine for Boeing's Phantom Works under a joint Defense Advanced Research Projects Agency (DARPA) and Office of Naval Research (ONR) effort that calls for the production of up to 14 engines for ground and flight tests. The flight-test timetable for the HyFly vehicle, originally aimed at a Mach 4 flight test by the end of this year, has been slowed by development issues and is not expected to get under way until 2006.
The DCR, which was tested in the windtunnel at speeds of Mach 4, 5 and 6.5 at NASA Langley Research Center, Virginia will power the missile after an initial rocket boost. The engine uses liquid hyrdocarbon fuel during hypersonic cruise to give the missile a range of around 1,100km (600nm) and a block speed of up to 4,400ft/s (1,340m/s). The DCR, which was originally conceived by Johns Hopkins University Applied Physics Laboratory in Maryland, is distinguished by its unusual multiple inlet design.
Two main inlet systems feed a dual-mode ramjet and scramjet (supersonic-combustion ramjet). One system feeds a subsonic gas generator in which a fuel-rich mixture is created before being mixed with supersonic air from the second inlet system. The heart of the DCR is a divergent combustor that allows the engine to transition from ramjet to scramjet mode at higher Mach numbers.
The latest tests follow work conducted in the Arnold Engineering Development Center's Aerodynamic Propulsion Test Unit (APTU) in Tennessee, which marked the first time a fully integrated hypersonic cruise missile engine using conventional liquid hydrocarbon fuel was tested at critical flight take-over (rocket boosted to air-breathing at Mach 4) conditions.
ONR and DARPA successfully conducted the first ground test of a full-scale, hypersonic missile engine using liquid hydrocarbon fuel on 30 May 2002 in a windtunnel. The test demonstrated robust operation of the engine at simulated hypersonic cruise conditions at Mach 6.5 at 90,000ft (27,500m).
GUY NORRIS / LOS ANGELES
Source: Flight International
