Development of a New Flap for a Light Utility Transport Aircraft

The Bush Hawk XP, which is produced by Found Aircraft of Canada, is a small, piston-engined utility transport aircraft suitable for bushplane operations. The original version was made in the 1960s, and it uses a sealed, plain hinged flap. In the latest production version the gross weight is increased substantially, necessitating an improved flap design to achieve better airfield distances and climb performance.This paper describes the aerodynamic design and development of a new single-slotted flap for the Bush Hawk. The flap shape and locations when deflected were optimized using modern CFD methods, and wind tunnel tests were bypassed. The features of the flap aerodynamic design, the aircraft structure, and the flap drive systems are described. Flight test results are presented for the Bush Hawk with the new flap; they show outstanding performance in its category.