June 18, 2007 Hypersonic flight moved a step closer to commercial reality on Friday when the Australian Defence Science and Technology Organisation (DSTO) and the US Defense Advanced Research Projects Agency (DARPA) successfully tested a rocket powered by one of the world’s fastest air-breathing engines. The scramjet-engined rocket reached speeds of Mach 10 - ten times the speed of sound - approximately 11,000 km/h – and would reduce the 5500 km flight from New York to London to a simple 30 minute affair or the 16,000 km long haul from New York to Sydney in under an hour and a half. Scramjets are air-breathing Supersonic Combustion RAMJETs and promise aircraft of hypersonic (Mach 5 plus) speeds. The flight reached an altitude of 530 kilometres, and reached speeds of Mach 10 during re-entry.
The flight took place at the Woomera Test Facility in South Australia under the HyCAUSE (Hypersonic Collaborative Australia/United States Experiment) collaborative effort between DARPA and DSTO, also representing the research collaborators in the Australian Hypersonics Initiative (AHI).
"This test has obtained the first ever flight data on the inward-turning scramjet engine design," said Dr. Steven Walker, Deputy Director of the Tactical Technology Office at DARPA. "DARPA will compare this flight data to ground test data measured on the same engine configuration in the US."
"We are pleased with this joint effort between the US and Australia and believe that a hypersonic airplane could be a reality in the not too distant future."
While DSTO was the lead Australian research agency for the flight, the AHI’s collaborative partners include the University of Queensland, the University of New South Wales at the Australian Defence Force Academy, and the Australian National University, together with the State Governments of South Australia and Queensland.
DSTO scientist Dr Warren Harch said hypersonic propulsion using supersonic combustion ramjet (scramjet) technology offered the possibility of very high speeds and fuel efficiencies.
“This technology has the potential to put numerous defence and civilian aerospace applications within our reach during the next couple of decades,” Dr Harch said.
Hypersonics is the study of velocities greater than five times the speed of sound (Mach 5) and could have a significant impact on Defence as well as on international transport and future access to space.
Future defence applications for hypersonic vehicles include long-range time critical missions, with civilian applications including low-cost satellite launching and high-speed aircraft.
Dr Harch said DSTO’s scientific contributions to the research program had been the computer modelling of the combustion processes, non-linear mechanics, guidance and control, and trajectory analysis.
“Assisting with telemetry collection is another important area, which presents quite a challenge when working with a vehicle travelling at hypersonic speeds,” Dr Harch said.
As part of its continuing commitment to a research program in Hypersonics, in November last year DSTO signed the $74 million Hypersonics International Flight Research Experimentation (HiFire) Agreement with the United States Air Force. Up to ten Hypersonic flight experiments are planned to occur at Woomera over the next five years under the agreement.
The Mach Number is named after the Austrian physicist Ernst Mach. Mach 1 is the speed of sound, which is approximately 760 miles per hour at sea level. An airplane flying less than Mach 1 is traveling at subsonic speeds, faster than Mach 1 would be supersonic speeds and beyond Mach 5 would be hypersonic.
