31 July 2002

London to Sydney in two hours. Or is it all just hot air?

By Cahal Milmo

A revolutionary jet engine that could cut the flight from London to Sydney to two hours has been tested successfully in open flight for the first time, scientists said yesterday.

Researchers hope that the prototype unmanned "scramjet", built partly with British technology, will have reached more than 5,000mph – or seven times the speed of sound – during a flight over the Australian desert.

The experimental hypersonic engine, which is called HyShot, could revolutionise travel by sending passengers into the stratosphere at extremely high speeds for the fraction of the current cost of flying. Blueprints for the scramjet were produced in the Forties but scientists have so far struggled to turn the technology, which has no moving parts, into working reality.

Last year, the American space agency Nasa watched its attempt to harness the power of the scramjet fail dramatically when its £100m prototype, the X-43A, went out of control and was destroyed over California.

But experts at the University of Queensland claimed success early yesterday when the HyShot was blasted 190 miles into sky above Woomera in the Australian outback. A small scramjet attached to a conventional rocket was activated for the final few seconds of a 10-minute flight as the vehicle plummeted back to earth. It was the first time that one of the jets, which operate by sucking oxygen from the atmosphere through specially shaped intakes into a combustion chamber, has fired in the open atmosphere.

Dr Allan Paull, the leader of the five-nation HyShot project, said: "It was a world first in what it attempted to do and we certainly did what we attempted. We've just got to analyse the data sent back during the flight to assess what happened within the scramjet, but I'm feeling pretty confident."

The scramjet develops such thrust that its speed is measured in kilometres per second rather than per minute. Moments before it was obliterated in the desert, scientists believe the HyShot would have reached 2.4km/sec, equivalent to 5,340 mph or Mach 7. The fastest
military jets can now reach Mach 3.

QinetiQ, formerly Britain's Defence Evaluation and Research Agency, one of the partners in the project, provided onboard monitoring equipment for yesterday's flight.

If scientists can now turn propelling a scramjet to the ground into a workable technology, the resulting aircraft would transform long-haul travel, making it possible to travel almost anywhere in two hours with the only by-product being water.

The engine can be propelled into the outer reaches of the Earth's atmosphere without a large fuel load, which would cut the cost of space travel from £3,000 per kg of cargo to £30.

But such a goal remains a long way from reality. Scramjets, which mix forced oxygen with hydrogen fuel to create the massive thrust, only work effectively at Mach 5, which means they have to be attached to conventional rockets to function. Even then, the friction caused by such vast speed would heat the fuselage to more than 1,000°C.

Passengers in a scramjet might be able to travel from New York to Tokyo in only 70 minutes but they would have to do so without any windows.

QinetiQ said yesterday that the next step in the Australian trials would be to fly a scramjet horizontally for two minutes before it crashes back to earth.