Design Aspects of the Elastic Trailing Edge for an Adaptive Wing

Abstract

According to predictions of market researchers a large growth in numbers of passengers as well as of airfreight volume can be expected for the civil transport aircraft industry. This will lead to an increased competition between the aircraft manufacturers. To stay competitive it will be essential to improve the efficiency of the new aircraft generation. Especially the transonic wings of civil aircraft with their fixed geometry offer a large potential for improvement. Such fixed geometry wings are optimized for only one design point characterized by the parameters altitude, mach number and aircraft weight. Since these vary permanently during the mission of the aircraft the wing geometry is only seldom optimal. As aerodynamic investigations have shown one possibility to compensate for this major disadvantage lies in the chordwise and spanwise differential variation of the wing camber for mission duration. This paper describes the design of a flexible flap system for an adaptive wing to be used in civil transport aircraft that allows both a chordwise as well as a spanwise differential camber variation during flight. Since both lower and upper skins are flexed by active ribs, the camber variation is achieved with a smooth contour and without any additional gaps. This approach for varying the wing's camber is designed to be used for replacement and enhancement of a given flap system. In addition the kinematics of the rib structure allows for adaptation of the profile contour to different types of aerodynamic and geometric requirements.