A sleek aircraft called the X-51A WaveRider has set the record for the longest hypersonic flight using an air-breathing “scramjet” engine. The engine operated for about 150 seconds – smashing the record set by NASA’s X-43 vehicle, which flew for 10 seconds or so in 2004.

The X-51A, a collaboration between the US military and private firms, was dropped from a B-52 bomber off the California coast at about 1700 GMT on Wednesday. A solid rocket booster then accelerated the aircraft to 4.5 times the speed of sound, or Mach 4.5, before its air-breathing engine took over and pushed the craft to about Mach 5. The scramjet engine burned fuel for about 150 of the 211 seconds that the X-51 was airborne before it dove into the ocean as designed.

The flight fell short of its intended goals: 300 seconds of flight time and a speed of Mach 6. At a certain point, the aircraft seemed to decelerate before accelerating again, and engineers are now analysing the flight data to figure out why, says Christina Kelly, spokesperson for Boeing Phantom Works, which designed the vehicle. “But they got 95 per cent of it right,” she says, pointing out that the vehicle successfully released from the B-52 and shot a straight course across the sky (see video).

It may take a couple of months to pinpoint the problem, and then engineers will incorporate any fixes into three other X-51 test vehicles, Kelly says, with the next flight likely to occur later this year.

The $250 million, eight-year project is one of several around the world that use scramjets(supersonic combustion ramjets). These vehicles reach rocket-like speeds but, unlike rockets, do not need to carry oxygen to ignite their fuel supply. Instead, they take oxygen from the atmosphere, using the shape of their bellies to suck in and compress air at supersonic speeds (see Spaceplanes and scramjets: A 50-year history).

The X-51A is the first scramjet to burn regular jet fuel. As The Register reports:

The test is significant aerospace news, as it is the first hypersonic flight by a hydrocarbon-fuelled scramjet as opposed to one running on hydrogen. Hydrogen scramjets have achieved Mach 10, but they are less likely to develop into practical aerospace craft as hydrogen is bulky and difficult to store in large quantities. Any hydrogen-fuelled aircraft, missile etc would be almost entirely fuel tank.

Ultimately, air-breathing engines are likely to be used to power high-speed missiles that could strike anywhere in the world within an hour or less, reports the Los Angeles Times.

They may also be used someday as reusable space planes, though it’s likely they would still need rockets to accelerate them to the speeds needed to escape Earth’s gravity. Some also argue that rockets alone will always be more efficient at space flight, since they can be smaller than air-breathing craft and also climb out of the atmosphere faster, subjecting them to lower stresses and temperatures.

Source: Maggie McKee, space editor

There are some people who want the comforts of home with them – even when ‘roughing it’ on safari in Africa.
For these five-star campers, BAE Systems and Design Q have come up with the ultimate in travel luxury.
The four-engined Avro Business Jet Explorer Four has been designed to land on short runways and uneven landing strips, delivering its wealthy passengers directly into wildlife areas.
Then, with the flick of a switch, a door on the side of the jet opens and a viewing platform extends from the fuselage – offering spectacular open-air views.

Plane for the plains: With the flick of a switch, the jet transforms into an open-air viewing platform for passengers. At a cool £16m, however, its only for the elite traveller
For a cool £16 million, A-list animal lovers will get the chance to by the ‘safari jet’, which has room for two pilots and eight passengers and crew.
Inside the aircraft, a galley kitchen can deliver gourmet meals to an eight-seat dining area, and large sofas fold out to provide on-board beds.
To top it all off, once passengers have had their fill of the good life and wildlife in any given area, they simply transform the aircraft back into its ‘flying mode’ and jet off to the next destination.

Opulence: As the sun sets on their exotic landing ground, passengers can relax in their spacious living area, complete with comfy sofas, as the crew serves them cool drinks.

Made to order: Further into the aircraft, a dining area and sleeping quarters can be found. Marble flooring and state-of-the-art entertainment systems can also be included.

The 100ft aircraft is being built to order in the UK, and a spokesman for BAE/Design Q says the aircraft will ‘offer a new level of sophistication for the discerning customer’.
With marble floors and quality finishes throughout, the interiors can be modified and designed to suit the individual needs of the owner.
For more remote locations and rougher landing grounds, the jet can be fitted with stronger and bigger tyres, and the fuselage can be strengthened to cope with the extra strain.
These images are an artist’s impression of the finished product, based on BAE designs.