Hybrid Laminar Flow Control Activities within the Frame of Clean Sky 2

Abstract

Reducing the environmental footprint of passenger aircraft is one of the most important challenges the aircraft industry is facing today. A decrease of fuel burn and consequently also CO2 plays an essential role in defining next generation aircraft. Obviously, any means to lower cruise drag are to be explored, where Hybrid Laminar Flow Control (HLFC) is one promising option. By influencing the boundary layer of a wing section in a way that delays the transition of the flow from laminar to turbulent, i.e. by increasing the laminar flow wing surface region, a significant drag reduction can be achieved. Within the Clean Sky 2 programme HLFC activities were focused on maturing existing HLFC principles with the goal to provide solutions which can be easily adapted for industrial needs of aircraft manufacturers. During the last eight years the HLFC activities concentrated on developing and maturing manufacturing technologies for HLFC up to a Technology Readiness Level (TRL) 5/6. Moreover, an innovative and simplified HLFC system was elaborated and its system integration into a wing was demonstrated with a final maturity of TRL 4. This paper aims to give an overview of the work performed and describes the chosen design approach to achieve an overall solution for an HLFC wing. In the end, the final overall solution and its key features is explained on a ground-based demonstrator manufactured within the programme.