High-Lift Challenges of High-Performance Wings

Abstract

One of the key-elements for high performance aircraft design is to design a high lift system within the given spatial constraints without having to increase the wing area to e.g. meet landing speed requirements or, vice versa allow to have a lower wing area, and therefore less wing weight and less drag. Recently and especially in the UP-WING project, very high aspect ratio wings have been designed to increase the aerodynamic performance. In addition to a careful aerodynamics and structural design due to the high flexibility of a high aspect ratio wing, the wing tip chord will be very short and can be easily subject to stall, especially at take-off conditions. However, wing tip stall has to be avoided since often it is not symmetric causing roll instability and is in addition coupled with loss of aileron effectiveness that will be in the wake of the area of separated flow.