An investigation has been made in the Langley 11-inch hypersonic tunnel to determine the ability to trim and maintain static longitudinal stability and control of a delta-wing configuration at high angles of attack. Three-component force tests were made at a Mach number of 6.7 and a Reynolds number of 0.47 x 106 (based on root chord) at angles of attack from 27° to 56°. It was found that the wings with the center of gravity located at 42 percent of the mean aerodynamic chord could be trimmed throughout the test angle-of-attack range without loss in longitudinal stability and control. If the center of gravity can be located farther rearward, the sometimes large losses in lift due to trimming can be avoided'(as less control would then be required in order to trim) without necessarily decreasing stability. Positive nose deflections yielded small pitching-moment increments at the higher angles of attack, but were stabilizing throughout the test angle-of-attack range. Negative flap deflections produced large pitching-moment increments and were destabilizing for all angles of attack. Unported trailing-edge flaps were found to be generally less effective than the smooth-bottom flaps.
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