Development of a Computer Assisted Toolbox for Aerodynamic Design of Aircraft at Subcritical Conditions with Application to Three-Surface and Canard Aircraft.

摘要

The thesis describes an investigation on the aerodynamics of three-surface aircraft at the conceptual design level. A 'three-surface aircraft' is characterized by having an additional lifting surface: a main wing, canard and horizontal tail. Contrary to the contemporary conventional and canard aircraft, the three-surface aircraft, having one additional lifting surface, offers potentially a capability to vary, hence optimize, the lift distribution between the surfaces over the center of gravity and weight envelope. The investigation suggests that the three surface aircraft will find only limited application as long as the positive static stability criterion is a prerequisite. If the stability criteria are relieved, the three-surface configuration might well be an attractive alternative to the conventional and canard configuration. The only application which seems likely for the common naturally stable aircraft, is a configuration for which the main wing is required to be positioned aft of the passenger cabin, allowing improved passenger comfort and a simplified main wing-fuselage structural joint, resulting in reduced structural weight.