An investigation into the aerodynamic efficiency of tailless aircraft

Abstract

From the perspective of aerodynamics, tailless aircraft are defended by many as potentially the most efficient aircraft configuration. The supporting argument being that the reduced surface area resulting from the tailless configuration directly results in reductions in drag. However, the efficiency of such configuration is realized through the utilization of active control systems. Without active control, the expected aerodynamic efficiency gains are partially or wholly negated by design compromises required to provide stability and control. The magnitude of washout required to stabilize such aircraft are usually quiet high, in the order of 8 to 10 degrees depending on the wing loading, airfoil type and control requirements of the aircraft. This high magnitude of wash out required dictates the lift distribution, such that only limited locations on the wing are flown at the design lift coefficient, thus increasing the associated induced drag. This paper discusses the efficiency of tailless configuration without active control and through the presentation of a case study undertaken with the use of both theoretical and empirical methods available proposes an all moving wing tip configuration as the design configuration of choice when considering tailless aircraft.