Structural Concept of an Adaptive Shock Control Bump Spoiler

Drag reduction technologies in aircraft design are the key enabler for reducing emissions and for sustainable growth of commercial aviation. Laminar wing technologies promise a significant benefit by drag reduction and are therefore under investigation in various European projects. However, of the established moveable concepts and high-lift systems, thus far most do not cope with the requirements for natural laminar flow wings. To this aim new leading edge high-lift systems have been the focus of research activities in the last five years. Such leading edge devices investigated in projects include a laminar flow-compatible Kruger flap [1] and the Droop Nose concept [2, 3] and these can be considered as alternatives to the conventional slat. Hybrid laminar flow concepts are also under investigation at several research institutes in Europe [4]. Another challenge associated with laminar wings aside from the development of leading edge moveables is the need to address the control of aerodynamic shocks and buffeting as laminar wings are sensitive to high flow speeds. One possible method of decreasing the wave drag caused by the aerodynamic shock is through the use of shock control bumps (SCBs). The objective of SCBs is the conversion of a single strong shock into several smaller and weaker λ-shocks resulting in a drag benefit when deployed correctly. A particular desirable characteristic of SCBs is that they would be adaptable in position and height as the shock position changes with varying conditions such as speed, altitude, and angle of attack during the flight. However, as a fixed case, SCBs can also help to control laminar buffeting by fixing the shock into given positions at the SCBs location. In this paper a concept for an adaptive shock control bump spoiler is presented. Based on a concept of a fixed SCB-spoiler an adaptive spoiler design with two conventional actuators is presented. Design drivers and interdependencies of important design parameters are discussed. The presented design is simple and aims for a high TRL without adding much complexity to the spoiler. It is robust and able to form a bump with a height of 0.6% which position can be adapted in a range of 10% chord.