Airfoil design and testing for high-lift rotorcraft applications

This paper describes the design of two series of rotorcraft airfoils for a heavy lift helicopter and a heavy lift tiltrotor. A newly emerging method of using a variable camber distribution is described. The use of a multi-point design optimization method was coupled with a traditional conformai mapping technique. The resulting airfoils were wind tunnel tested and provided validation for the method showing its strengths and weaknesses. The resulting airfoils were then analyzed using a Navier-Stokes CFD code, and compared to the design code and the test data. The results of this work demonstrate a method for design of heavy lift rotorcraft and the limitations of computational models to capture trailing edge separation. These limitations must be appreciated to avoid costly design mistakes.