CFD Calculations of Closely Coupled Scissor Wings-Inviscid, Viscous, and Vortex Lattice with Rollup Results

The Scissor Wing Configuration was investigated in the takeoff, landing, and low speed maneuverability area. In this area of operation the scissor lifting surfaces are close to each other and are strongly coupled aerodynamically. Two dimensional viscous and three dimensional vortex lattice results are presented for the scissor wings both of which used a NASA 64A-006 wing section. A multi-element vortex panel code was utilized for the inviscid predictions along with a momentum integral boundary layer code for the viscous predictions. A non-linear vortex-lattice code with wake roll-up was used for the induced drag predictions.

Studies were conducted with gap variations between the two wings, longitudinal variation between the two wings, variations in the relative angle between the two wings, leading edge flap variations, and trailing edge flap variations. Two dimensional results demonstrate that with proper selection of the gap between the wings, the longitudinal distance between the trailing edge of one wing and the leading edge of the other, and the relative angle between the wings improved lift-drag characteristics can be realized over the single wing. Both leading edge and trailing edge flaps, of proper percent chord and deflection, are shown to be able to simulate the optimum geometry without flaps. The dimensional vortex lattice results with wake rollup show a lower induced drag when compared to a comparable single wing.