Just like flocking birds, jet planes that fly in formation save energy by surfing on air currents created by the leaders. Manually keeping the plane in the sweet spot is exhausting, however, so engineers at NASA's Dryden Flight Research Center, UCLA, and Boeing are developing a system that does the job automatically. "A 777 airplane flying 250 days a year, going from New York to L.A. and back once a day, would save a half a million to a million dollars in fuel," says Brent Cobleigh of Dryden, the project's chief engineer.
Photographs courtesy of NASA/Dryden Flight Research Center
The savings are made possible by the sideways mini-tornadoes, or vortices, generated by the wingtips. One half of the vortex helps lift a trailing plane, whereas the other half makes it nose-dive, so precise positioning is a must. Cobleigh and his colleagues ran 26 flights using two F/A-18 fighter jets (above) equipped with enhanced GPS systems and wireless data links to help pilots stay on track. The trailing jet cut its fuel use by 14 percent to 20 percent. Testing of an autopilot version is on hold due to budget cuts, but if it pans out, the system could be a boon for commercial jetliners, which produce much larger, longer-lasting vortices. "You probably could set up a mile back. The passengers on board might not even see the lead airplane," says Cobleigh.