WIND-TUNNEL INVESTIGATION OF THE STATIC LONGITUDINAL STABILITY AND TRIM CHARACTERISTICS OF A SWEPTBACK-WING JET-TRANSPORT MODEL EQUIPPED WITH AN EXTERNAL-FLOW JET-AUGMENTED FLAP

摘要

A wind-tunnel investigation has been carried out to determine the static longitudinal stability and trim characteristics of a sweptback-wing jet-transport model equipped with an external-flow jet-augmented flap. The investigation included tests of the model to determine the effects of wing position, vertical position of the horizontal tail, and size of the horizontal tail.nThe results of the investigation indicated that static longitudinal stability and trim could be achieved up to a lift coefficient of about 6 with a horizontal tail having an area of about 25 percent of the wing area. In order to achieve this result, it was necessary to locate the horizontal tail well above the chord plane of the wing and to incorporate both variable incidence and an elevator. For the flap-down, power-off condition, the downwash factcr was found to be relatively large (0.8 to 0.9) the downwash factor decreased with increasing momentum coeffi¬cient, the greatest reduction occurring for the low tail position.