Success paves way for further trials of faster dual combustion ramjet-powered vehicle

The boost phase of the US Navy and Defense Advanced Research Projects Agency (DARPA) HyFly hypersonic tactical strike demonstrator has been successfully tested to speeds in excess of Mach 3, paving the way for follow-on tests of the Mach 6-capable dual combustion ramjet (DCR)-powered vehicle.

The tests, conducted in partnership with Boeing, the Office of Naval Research (ONR) and DCR developer Aerojet, were undertaken using a US Air Force Boeing F-15E which launched the HyFly vehicle over the US Navy’s sea range at the Naval Air Weapons Center at Point Mugu, California.

This test was the second of an apparently scaled back series of five HyFly flight tests that are due to be carried out from 2005 to 2007. In the first flight test, conducted on 26 January, an unpowered HyFly vehicle demonstrated safe separation from an F-15E as well as vehicle guidance and control functions. During the next three test flights, the HyFly vehicles will be powered by a booster and DCR, enabling speeds up to Mach 6. The original programme schedule called for up to eight flight tests, two of which were to use half-scale, short-duration engines, but it appears these plans have been scaled back.

The HyFly programme is aimed at proving the DCR-powered hypersonic missile concept with a missile configuration that Boeing describes as being “compatible with launch from surface ships and submarines as well as US Navy and Air Force aircraft”.

The core technology at the heart of the concept is the DCR, also known as ramjet-scramjet (supersonic combustion ramjet). In the DCR, the ramjet element of the engine provides a “pilot”, or combustion source, for the scramjet combustor.

Although initially aimed at developing a fast-response, hypersonic cruise missile, the HyFly concept could also be developed for potential space access applications by coupling the DCR with a turbine engine in a combined-cycle propulsion system.

Ground tests of the HyFly concept carried out in 2003 marked the first time a fully integrated hypersonic cruise missile engine using conventional liquid hydrocarbon fuel was tested at critical flight takeover speeds.

GUY NORRIS/LOS ANGELES

Source: Flight International