X-51A WaveRider hypersonic flight test vehicle

Here’s the scramjet being loaded onto a B-52.

Arcing through the hazy air above California, this is the incredible sight of a scramjet as it flies at six times the speed of sound.

The experimental aircraft set a record for hypersonic flight, blazing through the air for more than three minutes at Mach 6, or more than 4,500 mph.

The X-51A Waverider scramjet was released from a B-52 bomber last week before its engine took it to Mach 6 and it flew autonomously for 200 seconds.

Scramjets work by using oxygen rushing in through the engine at supersonic speeds to ignite hydrogen fuel.

The U.S Air Force said the previous record for a hypersonic scramjet burn was 12 seconds.

We are ecstatic to have accomplished many of the X-51A test points during its first hypersonic mission,’ said Charlie Brink, an X-51A program manager with the Air Force Research Laboratory.

We equate this leap in engine technology as equivalent to the post-World War II jump from propeller-driven aircraft to jet engines,’ Mr Brink said.

A passenger plane traveling at Mach 6 would cut the flight time from London to Sydney to little more than two hours.

Dr Andrew Coates, of the Mullard Space Science Lab at University College London, said the effects for passengers aboard a scramjet-powered plane would be ‘more akin to space travel than airline travel’.

They would need protective clothing to counteract the effects of the G-forces pressing on the body during acceleration to 5,000mph.

British scientists have worked on designs for scramjets but do not expect one to be available for commercial flights until at least 2020.

Professor John Fielding, Head of Aerospace at Cranfield University said that the prohibitive cost of scramjets would be a ‘major issue’ before any commercial design could be developed.