Chapter 1 - Historical Background and Current Scenario

Abstract

The idea of flying was born by seeing the birds evolutions in the air. First trials indeed, used structures that replicated somehow the animal wings, like pterodactyls, bats, birds themselves. However, as the technology evolved since the first engine-powered flight, the structures became stiffer and stiffer to afford the operational aerodynamic loads. However, the dream of having a full-deformable wing did not stop. Studies of adaptive wings and examples of innovative technology implementation continued without interruptions since the aircraft invention. Nowadays, the technology seems sufficiently mature to come to real morphing structures. At least, the first steps in that direction are being moved. This chapter deals with the origin of the concept of the variable wing and its evolution through history, remarking significant activities, whether theoretical or experimental that tried to implement adaptive aerodynamic surfaces on real aircraft. This trip will move from Europe to the United States and back, through the Americas, illustrating the examples that marked the history of adaptive wings. A specific detail will be given to the role of the University of Napoli “Federico II” and the Italian Aerospace Research Centre that have developed their own know-how through very significant cooperative projects since 2000. Shape variable structures have been illustrated per their main components (structural, actuation, sensor, control, and skin systems), describing for each of them the meaning, the technological status, and the future, expected evolutions and challenges. This text is enriched with a wide bibliography, updated in 2016, conceived as an operational help to the reader who wants to deepen specific concepts. This text is not exhaustive, but is thought to open all the possible ways to further investigations along any direction.