The US Air Force Research Laboratory (AFRL) has launched an initiative, dubbed Robust Scramjet, to expand the scale and operability of supersonic combustion ramjets (scramjets) in the run-up to the planned use of the propulsion concept for larger hypersonic and space launch vehicles in the next decade, writes Guy Norris.

Initial work awarded under the programme includes two $49.4 million contracts: one for Ronkonkoma, New York- based GASL, which is testing Pratt & Whitney's hypersonic GDE-1 (ground demonstration engine), and one for Johns Hopkins University in Baltimore, Maryland.

The five-year contracts cover the development of improved diagnostic tools and components for larger scramjets, including the construction of design concepts and "component-level engine simulations".

The initiative to start the scaling-up of scramjets comes in the wake of the recent launch of the joint US Department of Defense and NASA National Aerospace Initiative (NAI), aimed at early ground-based testing of key high-Mach technologies and flight demonstrations near the end of the decade (Flight International, 29 July-4 August).

Current and planned hypersonic test engines, including the P&W GDE-1 and follow-on GDE-2, are scaled for missile-sized applications.

The AFRL is concerned that increased attention needs to be given to design features for much larger engines in the 25,000-100,000lb-thrust (111-450kN) class which will be required for sub-orbital flight.

Source: Flight International