Blended blown flaps and vectored thrust for low-speed flight

Abstract

Short take-off and landing (STOL) capability is a recurring design goal for current and future aircraft design studies to meet reduced field length requirements, provide increased stores bring back capability, enhance carrier aircraft payload launch and recovery envelopes, and improve in-flight maneuvering. The Grumman Corporation has conducted a study to design and build an A-6 STOL demonstrator aircraft for the Navy that employes two-dimensional vectored nozzles and chordwise blowing for low-speed flight. If completed, this program would demonstrate operationally acceptable STOL performance with minimum loss in cruise performance. The results of a two-dimensional airfoil test determined that a plain blown flap with a large-radius, upper leading-edge blowing segment and a conventional-shaped trailing-edge section had better high-lift capability for the available blowing momentum of the design. Extensive three-dimensional wind tunnel testing verified predicted longitudinal characteristics, showed acceptable longitudinal and lateral-directional control, and defined design limitations associated with the high-lift system.