Low-speed aerodynamic characteristics of the double-delta supersonictransport.

Abstract

Extensive tests of the double-delta supersonic transport (SST) show that unique lowspeed aerodynamic characteristics are inherent using this concept, and the double-delta transport will offer low-speed handling qualities and safety of operation that will surpass the levels of current jet transports. Flow visualization studies show coiled vortex sheets that increase in strength with increasing angle of attack and provide steady unseparated flow well beyond the range of practical flight attitudes. The double-delta wing does not experience lift stall, pitch-up, or increase in drag due to stall. Lateral control power is retained and directional stability increases with increase in attitude. These favorable aerodynamic characteristics lead to a simple, conventional control system and an airplane that is simple to operate, displaying excellent stability, control, and safety margin characteristics. Abused takeoff procedures are less critical than for current jets because of greater lift and rate of climb margins. Lateral control power provides favorable aileron response during approach and landing. Ground effect simplifies the flare maneuver prior to touchdown. Directional and lateral control characteristics combine to provide excellent cross-wind landing characteristics. Achievement of these characteristics using a simple fixed geometry wing is one of the attractive features of the double-delta S ST.