- A plane that could change the future of travel has been
flown for the first time by Nasa at seven times the speed of sound.
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- The 12ft long X-43A aircraft used a scramjet engine on
its 11 second flight to reach a speed of 4,780mph.
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- The mission came more than half a century after the test
pilot Chuck Yeager broke the sound barrier and more than 100 years after
the Wright brothers' first powered flight.
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- Scientists believe that this latest breakthrough could
also usher in a new generation of air and space transport.
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- If the many engineering challenges can be overcome, this
technology could make it possible to fly from London to Sydney in a couple
of hours. The aircraft could also make it easier to launch payloads into
space.
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- The experimental plane uses a combustion ramjet so the
craft is not burdened with oxygen or an oxidant. Scramjets take their oxygen
from the air, which is forced into the engine at very high speed.
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- The X-43A scoops air molecules from the thin upper atmosphere
to provide enough oxygen for combustion. Nasa said the craft's brief flight
on Saturday broke the world speed record for an atmospheric engine.
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- Three years ago a similar test ended in an explosion.
This mission was the first time a non-rocket, air-breathing scramjet engine
had powered a vehicle in flight at hypersonic speeds.
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- The scramjet is revolutionary because the fuel is combusted
in a stream of air compressed by the speed of the aircraft. In a normal
jet engine the fan blades compress the air.
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- However, scramjets start to work only at about Mach 6,
or six times the speed of sound. They must first be given a jump start,
in this case from a modified Pegasus rocket. The mission began when a B-52B
bomber took off from Edwards Air Force Base with the aircraft under its
wing.
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- The X-43A was launched at 40,000ft, 400 miles off southern
California. The Pegasus rocket then took the craft to nearly 100,000ft
and a speed of 3,500mph.
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- In a complex series of vital manoeuvres, the 1.3 ton
wedge-shaped craft separated from its booster rocket and accelerated away
under the power of its scramjet.
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- The engine was designed to operate for about 10 seconds,
leaving the plane to glide through the atmosphere, conducting a series
of aerodynamic moves for several minutes before it splashed down in the
Pacific.
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- "It's been a great, record-breaking day," said
Larry Huebner, of the Nasa Langley Research Centre's Hyper-X division.
"We achieved positive acceleration of the vehicle while we were climbing
and maintained outstanding vehicle control.
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- "This was a world-record speed for air-breathing
flight."
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- In a reference to the Wright brothers he said: "To
put this in perspective, a little over 100 years ago a couple of guys from
Ohio flew for 120ft in the first controlled powered flight.
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- "Today, we did something very similar in the same
amount of time, but our vehicle under air-breathing power went over 15
miles."
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- Joel Sitz, the X-43A project manager at Nasa's Dryden
Flight Research Centre, said the test flight was a total triumph. "It
was fun all the way to Mach 7," he said.
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- "We separated the research vehicle from the launch
vehicle, as well as separating the real from the imagined. The ramjet-scramjet
is the Holy Grail of aeronautics in my mind.
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- "If you go from ground to space, you need to use
a ramjet-scramjet if you're going to do it in the most efficient way you
can."
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- The first X-43A flight ended in failure on June 2, 2001,
after the modified Pegasus rocket used to accelerate the plane veered off
course and was detonated. An investigation board found that preflight analyses
failed to predict how the rocket would perform. This left the control system
of the booster unable to maintain stable flight. The latest flight has
given researchers a new boost of confidence.
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- Griffin Corpening, the project's chief engineer at Nasa's
Dryden Flight Research Centre, said success was "all the sweeter because
of all the challenges we've had to step up to and overcome".
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- Previously, the world's fastest air-breathing aircraft
was the SR-71, which cruised slightly faster than Mach 3.
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- Nasa said that by the end of the year it could test a
vehicle at Mach 10 - around 7,000mph.
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- The flight is part of the £140 million Hyper-X
programme, a research effort designed to demonstrate alternate propulsion
technologies for access to space and high-speed flight within the atmosphere.
Nasa has a long history in hypersonic flight. The record-breaking X-15
reached a top speed of Mach 6.7.
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- For decades, engineers at Nasa's Langley Research Centre
have put futuristic flight vehicles through their paces in the centre's
hypersonic wind tunnel.
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- The Langley and Dryden Flight Research Centre, at Edwards,
California, jointly conduct the Hyper-X programme. ATK GASL, formerly MicroCraft
Inc, in Tullahoma, Tennessee, built both the vehicle and the engine. Boeing
Phantom Works in Huntington Beach, California, designed the thermal protection
and onboard systems.
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- However, a variety of technological hurdles mean that
it will be decades before such a plane could enter service. Nasa's role
in developing the technology remains in doubt, as the agency recently cut
funding for more advanced versions of the X-43A.
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- © Copyright of Telegraph Group Limited 2004. http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2004/03/29/
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