17 August 2002

Air-breathing jet flies at 5,000mph

By Roger Highfield, Science Editor

Aviation has entered the era of the hypersonic jet after an air-breathing engine exceeded 5,000mph.

The "hypersonic ignition" by the scramjet is one of the most important milestones in aviation since the sound barrier was broken in 1947. The technology could slash the cost of launching satellites, which rely on huge supplies of oxygen on board.

It also raises the possibility that, one day, passenger aircraft could fly from London to Sydney in a few hours.

The first detailed analysis of data from the launch last month in Australia shows that the scramjet, which has no moving parts, had reached 7.6 times the speed of sound (Mach 7.6). Hypersonic travel starts at Mach 5.

Rather than carry onboard oxygen to burn hydrogen fuel, a scramjet engine scoops up and compresses oxygen as it travels through the atmosphere, cutting launch costs considerably.

The initiative by the University of Queensland, backed by an international consortium that includes QinetiQ in Britain, involved the world's first flight test of an air-breathing ramjet engine, also known as a scramjet, on July 30.

After analysing data from the test, the project leader, Dr Allan Paull, of the University of Queensland's "HyShot" programme, announced yesterday: "Our honest understanding from preliminary data is that the experiment worked. We'll now be submitting the results to international peer review."

The test of the air-breathing engine capable of speeds in excess of Mach 5 was the first time engineers had made a scramjet work in flight, outside an air tunnel.

Last month, a Terrier Orion Mk70 rocket fitted with the scramjet had been launched from Woomera, a former British rocket testing range in the south Australian desert, to an altitude of nearly 200 miles. It was allowed to plunge back to Earth.

The scramjet was supposed to kick into action on the way back down 22 miles above Earth, with data transmitted by radio until it began to burn up at about 12 miles up. This ignition took place within the last few seconds of the 10-minute flight.

Then the team faced a nail-biting wait for the telemetry officers to come in from the dust with their precious data, before analysis could begin.

The ground-breaking Australian experiment, which cost about £500,000, came after a failed test a year ago of Nasa's multi-million dollar, unmanned X-43A scramjet prototype and a previous failed launch by the HyShot crew.

The HyShot scramjet has previously worked in a wind tunnel test, where the Mach 5 speeds at which it operates could be simulated.

Dr Paull said that he was negotiating with various groups to conduct a £30 million programme of six flights over five years, leading to a free flying scramjet engine.

Prof John Hay, Vice-Chancellor of University of Queensland, said: "Dr Paull has received approaches from top Australian researchers based in Nasa, Boeing and other organisations keen to return to Australia to work on the HyShot program if suitable funding is available."