Flutter data obtained by use of rocket-propelled vehicles in the transonic speed range for two pairs of high-aspect-ratio swept wings are presented herein. Two wings, swept 45°, fluttered at a Mach number of 0.89 and the other two wings, swept 60°, fluttered at a Mach number of 1.09.nA reference flutter speed was calculated' by means of a theory which includes effects of mode shape and sweep and involves the use of two-dimensional flutter derivatives based on flow normal to the wing. The agreement between the calculated and measured flutter speeds was very good, the experimental values being slightly higher in each, case. The closeness of the agreement indicates that the method of calculation gives usable results in the transonic speed range for swept wings of high aspect ratio, provided that the normal-flow Mach number is suffi¬ciently subsonic. A comparison of the test results with previous experi¬ments on straight wings of comparable aspect ratio indicates that the turn-up of the curve of flutter-speed coefficient against Mach number lies at higher Mach numbers for swept wings than for the unswept wings.
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