LOW SPEED WIND TUNNEL TEST OF A MORPHING LEADING EDGE

Because of the large potential of drag reduction natural laminar flow is one of the challenging aims of the current international aerospace research. For the achievement of the absolutely essential surface quality new concepts for the high lift system at the leading edge are required. Five years ago DLR started a new morphing activity aiming at a smart leading edge device [1]. The concept incorporates a flexible glass fibre structure of the leading edge which is actuated by conventional actuators and kinematic stations. The glass fibre structure is especially tailored to achieve a desired aerodynamic target shape and fully closed so that there are not steps and gaps for a high quality surface. In a first step a functional demonstrator was realized and tested in a ground test which is able to continuously alter the shape of a leading wing edge under wing bending loads. As a second step a European consortium of leading research groups and European aeronautic industry started the common project SADE in 2008 which aims to demonstrate the functionality of smart high lift devices in low speed wind tunnel tests. A functional full-scale demonstrator of 5m span and 3m chord is planned in the project. The paper gives a survey on the concept of the smart leading edge, the design of the wind tunnel demonstrator and on the recent results from the wind tunnel tests. The paper will focus on the validation of finite element calculations with the comparison of stress/strain data and the predicted deformations under aerodynamic loading