Design of a High-Lift System with Droop Nose Device

Abstract

T HE realization of wings with an extended portion of laminar flow, such as is being designed in the European project New Aircraft Concept Research (NACRE), imposes to use high-lift systems that preserve the smoothness of the wing as far downstream as possible. Our choice was to develop a system equipped with a single slotted trailing-edge flap and amorphing droop nose device. A similar concept was earlier presented by Morgan [1], and high-lift systems with a droop nose bending around a hinge line were also studied by Khodadoust and Washburn [2] and Khodadoust and Shmilovich [3]. In the next section we use a design of experiment (DOE) approach, starting from a general description of the high-lift airfoil consisting of 12 parameters. Five of them were selected and optimized by a response surfacemethod. The performance of the best candidate is analyzed in a third section and compared there with a high-lift system equipped with a vented Krueger leading-edge flap. In the fourth section a flow control system with vortex generators (VG) is investigated in order to improve the overall performance of the high-lift system with flexible droop nose device.