The unique variable-sweep wings of the F-111A (formerly the TFX) supersonic jet fighter were successfully used during flight for the first time on Wednesday (6 January) at Fort Worth, Texas.
C.A. people on ground
F-111 in flight, wings open
3 shots pilot out of plane and on ground
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Background: The unique variable-sweep wings of the F-111A (formerly the TFX) supersonic jet fighter were successfully used during flight for the first time on Wednesday (6 January) at Fort Worth, Texas.
The aeronautical trick demonstrated by the F-111 on Monday makes it potentially the most versatile plane ever built. The wings were outstretched for takeoff, enabling the plane to get in the air after a run of less than 3,000 feet. Then, at 10,000 feet, pilot Richard Johnson swept back the wings in stages to the highspeed position. Later in the flight, Johnson unfolded the wings again --- out to a position only 15 degrees back from a line perpendicular to the fuselage.
The F-111 is designed for use by both the US Navy and the Air Force, at both high and relatively low speeds, and at both high and low altitudes. The backward sweeping of the wings is intended to minimize the slowing effects of the shock wave that is generated when the plane exceeds the speed of sound. A swept wing, however, generates much less lift at slow speeds; thus the need for the outstretched position. In Wednesday's hour-long flight, the F-111 was pushed to a speed of only 450 miles an hour. But the backward wing sweep will make possible high-altitude speeds of about 1,665 miles an hour, about three time the speed of sound, and low-altitude speeds of more than 700 miles an hour.