Word: wings
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Dates: during 1960-1969
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Ample Incentive. Both the airlines and the military have long been anxious to fly faster in their subsonic jets. So there was ample incentive four years ago for Whitcomb and a team of NASA engineers at the Langley Research Center in Virginia to turn from the investigation of supersonic wing design to the problem of subsonic turbulence...
...source of the trouble was the upper surface of the conventional wing, which has a convex curve to provide lift.* When the plane reaches about 80% of the speed of sound, however, the velocity of the air flowing over the upper side of the wing reaches the sonic barrier. A shock wave forms about half way back from the wing's leading edge, disturbing the airflow and increasing drag-the resistance of air to the plane's passage...
...efforts to reduce turbulence, Whitcomb finally hit upon the design for what NASA now calls the "supercritical wing." To reduce the peak airflow speed and move the shock wave farther back on the wing, he drastically flattened the curvature of the upper wing surface. To compensate for the loss of lift that resulted, he increased the curvature near the wing's trailing edge and put a concave contour on the underside. "Some people think that I merely turned the wing upside down," Whitcomb says...
Reduced Drag. Wind-tunnel data revealed that when the airflow reached sonic and supersonic velocities along the redesigned upper surface, only a modest shock wave was generated near the trailing edge of the wing. There was negligible turbulence. Although the changes did not affect lift, drag was reduced by as much...
Elated by the results, NASA has ordered the construction of a flight-test version of Whitcomb's wing. At Edwards Air Force Base in California, the wing will be mounted on a modified F-8 jet-fighter and will undergo test flights in the summer of 1970. If the performance measured in Langley's wind tunnel is duplicated in flight, a new generation of more efficient subsonic jets may soon be cruising major U.S. air routes at speeds as high as 645 m.p.h...