New Ultra High Capacity Aircraft (UHCA) - Challenges and Problems from an Aeroelastic Point of View.

Abstract

To meet future air transport requirements, technical studies of a new class of Ultra High Capacity Aircraft (UHCA) with passenger capacities of 600 and possibly more are presently being conducted in many aircraft companies. Thereby, the aircraft designers are faced with a variety of new and challenging technical problems. Among those, aeroelastic problems are generally accepted to be of primary concern. It appears that with increasing size and hence structural flexibility of such super transport aircraft limits of technical feasibility are being approached. In the present paper the impact of aeroelasticity on the design of UHCA is highlighted. First, the adverse effects of static aeroelastic deformations on the controllability, aerodynamic performance and static flight stability of such highly flexible aircraft with swept-back wings are discussed,and the design concept of an aeroelastic adaptive wing is outlined. Then, as a dynamic aeroelastic key problem, the wing-with-engine nacelle flutter stability problem is analyzed, and corresponding flutter stability boundaries are presented. Finally, some other important dynamic aeroelastic problems relevant to UHCA are pointed out, namely the gust load design problem, the influence of structural flexibility on the dynamic flight performance and stability, and aeroservoelastic problems arising with the application of automatic flight control systems using active control technology.