Formation Flying Commercial Aircraft - Assessment Using a New Approach - Wing Span Load and Camber Control

Abstract

The idea of flying commercial aircraft in formation to reduce fuel usage, has been around for some time. There are many results available using idealized approaches e.g. vortex lattice formulations. In view of the greater importance being attached to environmental aspects, the need has arisen to evaluate the possible advantages and disadvantages. This paper steps up the analysis level exploiting a recently developed design method that allows span loading and camber control on wings with without winglets. The method has been adapted to assess the aerodynamics of wings in formation and then to redesign them to eliminate induced roll effects. From a limited number of flight formation configurations assessed so far, the method predicts induced drag reductions of near 30%, affording overall drag reductions of the order of 15%. The benefits may well be larger, using other formation spacing parameters. Limited results using an Euler solver reflect benefits of the same order. The technique has proved to be easy and robust in use. It is enlightening as it gives, at every stage, a feel for what is happening in terms of camber development, pressure distributions and Centre of Pressure location. Favourable characteristics of the configuration can be enhanced whereas those that are not beneficial can be minimised or avoided as the design progresses Several avenues of further work and development have arisen.