QUIET PROPULSIVE-LIFT TECHNOLOGY READY FOR CIVIL AND MILITARY APPLICATIONS.

Quiet propulsive-lift technology has reached the point of useful application. This statement reflects more than two years of flight research with the Quiet Short-Haul Research Aircraft (QSRA) at the NASA Ames Research Center that culminated in repeated unarrested landings aboard the USS Kitty Hawk in July last year. The QSRA, modification of a De Havilland C-8 Buffalo, was designed as an austere research aircraft for investigating terminal equals -area operations with an advanced propulsive-lift aircraft. The modification to the C-8 consisted of adding a new swept wing with four top-mounted Lycoming YF-102 turbofan engines to provide high levels of propulsive-lift through upper-surface blowing (USB). The low budget of the QSRA program motivated fixed landing gear and leading-edge flaps. They limit top speed to 190 knots. Nevertheless, the new wing and propulsion system have an aerodynamic configuration capable of efficient cruise at a Mach number of 0. 74. Studies by Boeing Commercial have shown that this technology could also be used to advantage in civil transports.