Venture hopes to make jets seen but not heard

A U.S.-British team of researchers from academia and the aerospace industry believes that the passenger aircraft of the distant future will not only be fuel efficient but also virtually silent.

Leaders of a long-range research venture called the Silent Aircraft Initiative were scheduled today to release a conceptual design for a plane they say could cut through the air with practically no sound bothering those below, thanks to its unique shape and design features to limit engine noise.

The design adds a new twist to aviation’s long history of mixed success developing flying wings designed to be more fuel- and space-efficient than conventional aircraft with long, narrow fuselages.

The design, to be announced in a news conference at the Royal Aeronautical Society in London, would blend fuselage and wings together so that the entire airframe provides lift -- an approach that to date has been confined largely to payload-carrying military aircraft such as long-range bombers.

The body shape of the “silent aircraft” would allow for a slower landing approach and takeoff to cut airport noise -- a form of environmental pollution that makes it politically unpopular to expand airports and flight schedules.

“The silent aircraft can help address this concern and thus aid in meeting the increasing passenger demand for air transport,” said Edward Greitzer, professor of aeronautics at the Massachusetts Institute of Technology.

Even if he’s right, don’t expect to see -- or hear -- such a plane anytime soon. The project is aimed at establishing research knowledge that could lead to development of an aircraft by 2030. Whether such a plane could become a commercial success is anybody’s guess.

But the project, led by researchers at Cambridge, Mass.-based MIT and Cambridge University in England, has plenty of commercial interest. The two universities say more than 30 aviation companies around the world participated in the design, including aircraft maker Boeing Co. and engine maker Rolls-Royce.

Rolls-Royce wouldn’t participate if the project didn’t have the potential to help shape future aircraft design, said Martin Brodie, a spokesman for the London-based company.

“We have a very strong record of involvement in environmental programs anyway, so this is just a logical thing for us to get involved in,” Brodie said.

More than 40 researchers from MIT and Cambridge as well as engineers from the 30 companies have been collaborating on the design since the project’s launch three years ago. Funding has come largely from the British government’s Department of Trade and Industry, which committed money seven years ago to establish the Cambridge-MIT Institute, a joint venture between the schools that also has worked on other projects.

For now, the aviation project’s goal is not to produce a marketable aircraft.

“The goal was to find out what technologies would be required, and what an aircraft would look like if a step-change in noise reduction was one of the key drivers for design,” said Zoltan Spakovszky, an MIT aeronautics professor and a chief engineer on the project.

One aspect of the plane’s design eliminates flaps -- hinged sections on the rear of each wing -- to reduce a major source of noise as the plane cuts through the air at takeoff and landing.

To reduce sound reaching the ground, the jet engines would be embedded into the plane’s body, rather than hung from the wings as on conventional airliners.

The engines would have variable-size jet nozzles, allowing slower jet propulsion during takeoff and landing but efficient cruising at higher speeds.