Calculation and Comparison of Aerodynamic Coefficients of a 4-Bladed Tilt Rotor at Cruise and Hover Design Points (EUROFAR).

Abstract

The numerical investigations have been made to compare results of the Lifting Body Surface-Method (LBS-Method) with those of other methods. The results were presented on the EUROFAR Rotor Aerodynamics Meeting at MBB, Ottobrunn, 6 December 1989. Basic equation of the LBS-Method is a linearized integro-diffential equation well known a Ffowcs Williams/Hawkings equation. The solution is obtained by a velocity and an acceleration potential. The LBS-Method was developed for wings, propellers and rotors in subsonic flow. In order to include viscous effects a transpiration model can be used. However, here experimental 2-D airfoil characteristics are considered. It is shown that a modification of the LBS-Code is necessary for the efficiency that has to be replaced by the "Figure of Merit".Computed and compared are aerodynamic coefficients of a 4-bladed rotor at cruise and hover design points.