Designing a Combat Aeroplane: Interdisciplinary Aspects

Abstract

The major engineering disciplines involved in the design of an aeroplane, namely aerodynamics, structural design and internal power, mechanical and avionics systems design, are introduced. It is shown how the requirements for a multi-role combat aeroplane influence these branches of engineering and how they interact. Examples are chosen which illustrate the interactions. Wing design is driven by aerodynamic considerations, but strength and stiffness considerations strongly influence and constrain the design; fuel carriage also has an influence. Modern developments in flight control system design, exploiting Active Controls Technology, are described, and it is shown how these remove some of the restrictions previously imposed by the requirement for inherent aerodynamic stability. The benefits of ACT combine with those of advanced variable-camber wing design to provide very significant benefits in combat performance, but ‘fail-safe’ design measures must be taken, necessitating multiplex redundancy in sensing, computing, actuation and power supplies. It is shown how performance requirements influence engine and air intake design, namely the choice of engine reheat boost and bypass ratio and the type of intake. Its location interacts strongly with weapon carriage layout, which is affected by weapon drag, flutter and stability considerations.