Morphing Aircraft: An Improbable Dream?

Compliant aircraft, with a range of deformations comparable to birds, has been a dream for many years. Earlier aviation pioneers tried to replicate aspects of bird flight, but higher air speeds and larger payloads have required aircraft design to deviate from their biological inspiration. The design of conventional fixed wing aircraft can only be optimized for a limited region of the flight envelope; mechanisms such as deployable flaps and wing sweep are used extensively to enlarge this envelope. The development of more accurate analysis tools, advanced smart materials, and the increasingly demands for improved aircraft performance, are driving research into compliant morphing aircraft. These aircraft have the potential to adapt and optimize their shape to improve flight performance or achieve multi-objective mission roles. However this technology has rarely been adopted on production aircraft. This paper will critically review the progress made to date on compliant morphing aircraft research, and summarize the challenges that need to be addressed before such technology can be adopted widely. In particular the need to demonstrate system level performance benefits for morphing technology is emphasized.