Improving flight safety
Engineers propose new tail fin design

By Sarah Yang, Public Affairs

29 November 2001 | Wake turbulence — the strength of air disturbance generated in a plane’s wake — may have played a role in the Nov. 12 crash of an American Airlines Airbus A300 in New York. New research in the School of Engineering suggests that when triangular flaps are added to the design of aircraft wings, the flaps dramatically cut the strength of turbulence created in a plane’s wake.

In the days following the recent crash in Queens, which killed 265 people, accident investigators reported that the tail fin of the Airbus jet had sheared off after the pilots struggled against the wake turbulence left by a Boeing 747 that had taken off less than two minutes earlier.

“The wing we designed could make substantial differences in flight safety and airport capacity,” said Ömer Savas, professor of mechanical engineering. He and former grad students Jason Ortega and Robert Bristol experimented with wing designs that would quickly render wake turbulence harmless.

For decades, engineers have sought ways to disrupt the stability of “wake vortices,” or wak turbulence, in efforts to transform the forceful swirls into benign puffs of air. Wing designs have included small pulsing jets mounted at the wing tips, spars and oscillating spoilers. Most of the designs have been ineffective or impractical; some involved moving parts that required more maintenance.

Savas found in testing a design with triangular extensions jutting behind each wing that wake vortices dissipated two to three times faster than traditional wing designs.

“Our model is a significant improvement over current designs,” said Savas. “In addition to improving safety, cutting the distance that the wake vortex remains coherent would allow planes to take off and land closer in time together without compromising safety. That leads to more efficient use of runway capacity, a major problem at congested airports around the country.”

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