September 9, 2005

Engineers Plan Out ‘Silent’ Airliner of the Future

DUBLIN -- A new generation of barely- audible, fuel-efficient passenger aircraft described as "flying wings" with "virtual windows" could arrive in two decades, engineers from Britain's Cambridge University said on Friday.

"The noise level we're looking for would be to take it below the background noise that people experience outside airports ... below traffic noise levels," said Paul Collins, a mechanical engineer with the "Silent Aircraft Initiative."

It will be 20 years or more before the concept, which looks more like the U.S. military's B-2 Stealth Bomber than a jumbo jet, could enter service.

But a noise reduction approach that goes beyond the aircraft's frame and engines means there could be benefits much sooner for those living beneath flight paths.

"We're not just looking to reduce the noise an aircraft makes but also to change the way it's flown to produce significant noise savings," aerospace engineer Tom Reynolds told journalists at the British Association for the Advancement of Science's annual festival in the Irish capital.

Working with air-traffic controllers, the researchers hope they can begin flight tests with conventional aircraft as early as next year to look at a new, steeper landing approach that would limit the amount of time planes spend at low altitudes.

The scientists hope that, with oil prices at record highs, their new designs will make economic as well as environmental sense.

"It's really a win-win from an operational point of view because you get less noise and less fuel burn at low altitude," Reynolds said of the project, backed by aerospace giants such as Boeing, Rolls Royce and British Airways.


The men, who are working with the Massachusetts Institute of Technology in the United States, believe their concept could cost as much to develop and buy as today's passenger jets but should be much cheaper to run thanks to its unusual shape.

"The blended wing body is an inherently more efficient design," said Reynolds, pointing out that, unlike conventional airliners, the entire body of their aircraft will provide lift.

In terms of silencing, Anurag Agarwal, another aerospace engineer on the project, said mounting the engines on top of the plane would bounce much of the noise upwards off its surface.

Longer engines would also allow space for more mufflers while widening them might also help: "If we push more air through at a lower velocity we get less noise," Agarwal said.

The triangular cabin, merging into the wings, means the configuration inside will be unlike anything flying today.

"It's like a flying wing and the passengers are accommodated in this wing," said Agarwal of a layout providing more space.

For passengers concerned they may be stuck in a middle aisle without a view, Reynolds said one solution may be to remove the windows altogether, thereby reducing cut outs in the fuselage.

"You could compartmentalize the cabin into a number of narrower sections and if you combine that with virtual windows you may not, in real terms, experience anything different."

The initial plan is to work on a transatlantic model the size of a Boeing 767 with 250 seats and a 4,000-mile range but Agarwal said it could be expanded to carry 800: "One advantage is that it becomes more efficient as you make it bigger."