Installation Effects of a Propeller Over a Wing with Internally Blown Flap

Aiming at maximum climb performance, the lift-to-drag ratio and the installed thrust of a STOL transport aircraft can be enhanced through a synergistic propeller integration. ReynoldsAveraged-Navier-Stokes simulations have been conducted on a generic geometry to quantify the aerodynamic interactions between the propulsion system and a wing with blown flaps. At takeo , a conventional tractor configuration shows a distinct thrust vectoring e ect inducing large lift and drag increments. By relocating the propeller at midchord above the wing, the lift over drag ratio and the installed e ciency are considerably improved while losing half of the lift augmentation. Compared to a simple over-the-wing installation, a channel wing design with a partially embedded propeller has the advantage that the thrust vector is closer to the center of gravity resulting in a smaller pitching moment due to thrust. An issue of over-the-wing propellers is the inhomogeneous inflow to the propeller which leads to cyclic variations in blade load and reduced net thrust.