DESIGN OF A HIGHLY EFFICIENT TRANSPORT NLF AIRCRAFT WITH A BACKWARD SWEPT WING AND A LONG SINGLE-AISLE FUSELAGE

Abstract

This paper presents results of the numerical aerodynamic design and analysis of a highly efficient passenger aircraft with a backward swept wing (BSW) and a long single-aisle fuselage. Large efficiency is obtained with large aspect ratio wings and using natural laminar flow (NLF) shape designs. Several wing planforms are considered. Design cruise Mach number is increased by considering planforms with increasing wing leading- edge (LE) sweep. For each planform case with a fixed (LE) sweep a detailed NLF wing design was performed for the corresponding cruise design Mach number. With increasing LE sweep, it becomes more difficult to achieve NLF in the inner wing due to crossflow instability. Here, a natural laminar flow (NLF) design was still possible for the largest investigated LE sweep case by using a crossflow attenuated NLF (CATNLF) section design strategy. For the final high swept planform also off-design flow conditions were considered in order to improve the performance for these conditions. A final designed shape was achieved. It provided the flight shape (twist) and jig shape (bending) for a test in the European Transonic Wind Tunnel (ETW). First results of the final wind tunnel geometry are presented.