Cost-effective HLFC design concept for transport aircraft

Abstract

Resource-efficient flying is a central goal of current and future developments in aviation. Laminar technology is one of the most promising ways to contribute for the achievements to reach the goals of Flightpath 2050. The hybrid laminar flow control (HLFC), based on the combination of active flow control by boundary layer suction and natural laminar flow downstream, is a favourable way to laminarize leading edges with large sweep angle. While the resistance-reducing effective of HLFC technology has already been proven with wind tunnel and flight tests, solutions for the cost-effective production are still subject of current developments. The particular difficulty lies in the combination of industrially producible designs while maintaining the aerodynamic performance. For this purpose, DLR is developing a leading-edge design, based on a cost-effective, micro-perforated outer skin with intrinsic pressure drop distribution. Furthermore the leading edge will be fully demountable for maintenance and cleaning reasons. The resulting combination of low manufacturing and operational costs should leverage the breakthrough of HLFC technology for industrial application. In the following paper the aerodynamic and structural design of the leading edge as well as the manufacturing technology of the outer skin are described. In addition the structural concept for fin application is presented. The presented work and achieved results were developed in the CleanSky2 project NACOR (New Aircraft Configurations and Related Issues, Grant Agreement No. CS2-AIR-GAM-2014-2015-01), funded by the European Commission and the Federal Ministry for Economic Affairs and Energy.