Silent jet
 

No flight of fancy: silent jet could change aviation

No noisier than a washing machine … the "silent jet" could be in the air by 2030.

November 7, 2006

CAMBRIDGE, England: A radically redesigned passenger jet could alleviate a complaint that inhibits the development of airports - the deafening sound of take-offs and landings.

Researchers from the Massachusetts Institute of Technology and Cambridge University spent three years designing the wide, streamlined jet, which they were expected to unveil in London yesterday. The "silent jet", which would sound about as noisy as a washing machine, 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.

The breakthrough could change aviation.

"People are still willing to pay more for the convenience of a closer-in airport," said Richard Aboulafia, a vice-president at Teal Group, an aerospace consulting firm in Fairfax, Virginia. "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 has been a focus of manufacturers such as Boeing and Airbus, and jet engine makers including General Electric, United Technologies and Rolls-Royce.

Their efforts have mainly involved tweaks to existing technologies, but the MIT-Cambridge team set out to redesign the plane from the ground up.

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 stabiliser common at the tail of passenger jets, instead using a pair of stabilisers at the wingtips.

The proposed aircraft has a 68-metre wingspan and is 44 metres 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.

The design allows the aircraft to remain in the air at slower speeds, which would allow it to cruise in for landing more quietly. It does not use wing flaps, which 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 engines in pods suspended under the wings, the silent jet uses three engines built into the middle of the aircraft, at the rear. They take in air from above the wing, which helps insulate people on the ground from jet noise at take-off.

Reuters