September 9, 2005

Engineers plan out “silent” airliner of the future

By Paul Hoskins

DUBLIN (Reuters) - 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

"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

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

"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."