Biplane Design Could Break Sound Barrier
March 15, 2012

Biplane Design Could Break Sound Barrier

MIT researchers have found a way to produce a cheaper, quieter and fuel-efficient biplane that is capable of traveling at supersonic speeds.

The team has shown through a computer model that a modified biplane can produce significantly less drag than a conventional single-wing aircraft at supersonic cruise speeds.

Qiqi Wang, an assistant professor of aeronautics and astronautics, said less drag would allow the plane to require less fuel, making it cheaper to fly, and would also make it quieter.

“The sonic boom is really the shock waves created by the supersonic airplanes, propagated to the ground,” Wang said in a press release. “It´s like hearing gunfire. It´s so annoying that supersonic jets were not allowed to fly over land.”

The Concorde supersonic jet use to bring passengers from New York to Paris in just three-and-a-half hours.  However, high costs, limited seating and noise disruption lead the plane to retire from service on November 26, 2003.

Wang designed a way for the jet's wings to be positioned one above the other, canceling out the shock wave produced from either wing alone.

The concept for the plane is derived from German engineer Adolf Busemann's idea from the 1950s.  He came up with a biplane design that essentially eliminates shock waves at supersonic speeds.

Wang and colleagues designed a computer to simulate the performance of Busemann's biplane at various speeds.  They found that smoothing out the inner surface of each wing slightly helped create a wider channel through which air could flow.

They also found that by bumping out the edge of the higher wing, and the bottom edge of the lower wing, the conceptual plane was able to fly at supersonic speeds, with half the drag of the Concorde.

“If you think about it, when you take off, not only do you have to carry the passengers, but also the fuel, and if you can reduce the fuel burn, you can reduce how much fuel you need to carry, which in turn reduces the size of the structure you need to carry the fuel,” Wang said in a press release. “It´s kind of a chain reaction.”

The team now plans to design a three-dimensional model to account for other factors that affect the flight.

The group will publish their results in the Journal of Aircraft.