Methodology for Evaluating a Distributed Variable-Camber Trailing-Edge System in Preliminary Aircraft Design

Abstract

A controlled adjustment of the wing camber during cruise flight by an extension of each separate flap allows for wing shape optimization, depending on the current mission point including the prevailing conditions, contributing to an increase in efficiency. This is referred to as variable camber (VC). This paper aims to investigate a methodology for a retrofit application of VC technology with differential flap setting, especially for a segmented trailing-edge system at the overall aircraft level in the preliminary design phase. In addition, an assessment is conducted to clarify whether actuation on the basis of a central shaft system or a decentralized power-by-wire system is advantageous. The investigation is based on a commercial aircraft with a maximum takeoff mass of 270 t and compares the potential of a VC application with an aerostructural twist optimization of the wing. Different configurations of the trailing-edge flaps, ranging from a common two-flap configuration up to a configuration with six trailing-edge devices, are covered in order to give a holistic implementation recommendation, including actuation and flap segmentation. Depending on the reference aircraft, the study shows a considerable fuel-saving potential for VC applications, e.g., 3.5% for the pre-optimized reference on a long-range mission.