A team of 40 researchers from Cambridge
University and the Massachusetts Institute of Technology
spent three years working on the wide, streamlined jet,
which they plan to unveil in London on Monday.
The "silent jet," which from outside an airport would sound
about as noisy as a washing machine or other household
appliance, would carry 215 passengers and could be in the
air by 2030.
"Noise really is one of the major barriers to airport
expansion and the expansion of flights," said Edward
Greitzer, an MIT professor who helped run the project. "It
gets a lot of complaints."
The breakthrough could bring a welcome change to aviation,
industry experts said.
"People are still willing to pay more for the convenience of
a closer-in airport," said Richard Aboulafia, vice president
at Teal Group, an aerospace consulting firm in Fairfax, Va.
"There is an economic value to being able to keep your air
transport close in town, which means you've got to be
quiet."
Reducing noise in recent years has been a focus of makers of
planes, such as Boeing and Airbus, and jet engines,
including General Electric, United Technologies and
Rolls-Royce.
While their efforts have mainly involved tweaks to existing
technologies, the MIT-Cambridge team set out to redesign the
plane from the ground up, with a focus on quiet.
Instead of the tube-and-wing model common today, the Silent
Jet is a flying wing, evoking current "stealth" military
aircraft. It lacks the central vertical stabilizer common at
the tail of current passenger jets, instead using a pair of
stabilisers at the wingtips.
The proposed plane has a 222-foot wingspan and is 144 feet
long from nose to tail, comparable in size to a Boeing 767.
"You take the fuselage and you squish it, and you spread it
out, and it's an all-lifting body," said Zoltan Spakovsky,
an associate professor at MIT who worked on the project.
The design allows the plane to remain in the air at slower
speeds, which would allow it to cruise in for a landing more
quietly. The plane does not use wing flaps, which are common
on today's passenger jets and create much of the landing
noise.
The MIT-Cambridge team also designed what they said could be
a quieter and more fuel efficient engine system. Rather than
placing the jets in pods suspended under the wings, the
silent jet uses three engines built into the middle of the
plane, at the rear. They take in air from above the wing,
which helps to insulate people on the ground from jet noise
at takeoff.
Airplane makers may prove more likely to cherry-pick
individual technologies developed for the new jet than to
adopt the whole redesign for their products, executives
said.
"In a project like this, the idea is to really focus on one
goal and see what you could do in the extreme," said Billy
Glover, director of environmental performance at Boeing
Commercial Airplanes in Seattle, one of the industry experts
the researchers have used as a sounding board. "But as you
go to a real design process, you have a lot of other
trade-offs."
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