Engineers tweak scramjet

A new international entry into the hypersonic arena will be tested on Saturday. Hyshot III, a prototype scramjet part-developed by Ministry of Defence spin-out Qinetiq will be released from aboard a rocket over the South Australian desert at 12.30PM local time.

The University of Queensland-run trial is a kamikaze mission for Hyshot III. From an altitude of 330km, it will accelerate towards the Earth. At 35km above ground, the missile-like craft will have gained enough speed for the experimental engine to be switched on.

If all goes to plan Hyshot III will then go hypersonic - the team are aiming for Mach 7.6. That's a face-rearranging 9000km/h.

Engineers will have six seconds to monitor the performance of the scramjet before it's turned off. Half a minute and 23 kilometres later the £1m Hyshot III will eat sand.

Scramjets - supersonic combustion ramjets - work by harnessing the enourmous air pressure generated at supersonic speeds to force large amounts of oxygen into the combustion mix. Conventional supersonic jets have to slow the air down to use it.

Predecessor Hyshot II was the first scramjet to fly successfully. It went the same speed as the Hyshot III team are after.

The idea this time is to improve efficiency. Queensland associate professor Michael Smart told the Melbourne Age: "It actually looks like a big silver bullet and it has intakes to take in the air at the front of it, whereas the previous one, HyShot II, was a very rectangular-looking thing with wedges. This bullet shape has, hopefully, a more efficient intake."

It's not rocket science

If the technology can be made viable, scramjets have the beating of conventional rockets too. Not having to carry their own oxygen in solid or liquid form means they're much more efficient.

While military applications are obviously the driver for the work, the researchers hope hypersonic travel will eventually be available to the great unhosed. London to Sydney would take just two hours.

As The Register has reported in the past, things can go spectacularly wrong with these experiments. Project leader Dr Allan Paull told the BBC: "You are dealing with extremes of conditions. You're working out on the edge and with a lot of the stuff no one has ever tried before. You've got to expect things to go wrong".

For details of American efforts to get scramjets fired up see here.®