Active Flaps and Slats for Rotor Performance Enhancement

The comprehensive analysis UMARC was used to quantify the capabilities of trailing-edge flaps (TEFs) and leading-edge slats for helicopter performance improvement in high-speed forward flight. Suitable combination of lower harmonic TEF inputs were shown capable of reduction of rotor power requirement by about 4-5% at advance ratio of μ = 0.4. Leading-edge slats were shown to enhance the maximum rotor thrust by 25-30% at advance ratios larger than 0.2 and reduce power requirements by 10-20% at high thrust levels. Combining suitable flap deployments with slat deployments yielded a further power reduction of about 2%.