ABSTRACT |
Lift (L) and drag (D) characteristics have been obtained in flight for the X-29A airplane (a forward-swept-wing demonstrator) for Mach numbers (M) from 0.4 to 1.3. Most of the data were obtained near an altitude of 30,000 ft. A representative Reynolds number, for M = 0.9 and a pressure altitude of 30,000 ft, is based on the mean aerodynamic chord. The X-29A data (forward-swept wing) are compared with three high-performance fighter aircraft뾲he F-15C, F-16C, and F/A18. The lifting efficiency of the X-29A, as defined by the Oswald lifting efficiency factor, e, is about average for a cantilevered monoplane for M = 0.6 and angles of attack up to those required for maximum L/D. At M = 0.6 the level of L/D and e, as a function of load factor, for the X-29A was about the same as for the contemporary aircraft. The X-29A and its contemporaries have high tran-sonic wave drag and equivalent parasite area compared with aircraft of the 1940s through 1960s.
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