1 OVERVIEW ON DRAG REDUCTION TECHNOLOGIES FOR CIVIL TRANSPORT AIRCRAFT

Abstract. Drag reduction is one of the main objectives of the transport aircraft manufacturers. The drag breakdown of a transport aircraft at cruise shows that the skin friction drag and the lift-induced drag constitute the two main sources of drag, approximately one half and one third of the total drag. Hybrid laminar flow technology and innovative wing tip devices offer the greatest potential for drag reduction. Aircraft performance improvement in off-design conditions can also be obtained through trailing edge optimisation, control of the shock boundary layer interaction and of the boundary layer separation. The paper will give an overview of the results obtained for the different mentioned topics and will try to evaluate the potential gains offered by the different technologies