Performance enhancement evaluation of an actuated trailing edge flap

Abstract

Abstract An analytical evaluation of the performance enhancement due to a servo-actuated trailing edge flap was carried out using the coupled rotor-fuselage model (CRFM). The performance enhancement from a trailing edge flap is achieved by introducing effective camber around the azimuth for a nominal aerofoil. An investigation on the best combination of flap parameters, namely the span, position, chord and deflection was carried out in order to identify an optimal configuration within given design constraints. The effects on vibratory control loads over a range of speed for a flap of 10% span, 20% chord, actuated at once per rev has expanded the retreating blade envelope for a Lynx aircraft by some 20kt. The flap hinge load was also examined and it was found not to be excessive. It was also confirmed that an actuated trailing edge flap does not have adverse effect on the pilot's control inputs to trim to a particular flight condition. This paper will discuss the aerodynamic enhancements derived from the application of the trailing edge flap and present conclusions drawn from this study.