Concept Aircraft: Prototypes, X Planes and Experimental Aircraft (Aviation Factfile)

X stands for the unknown in mathematics and physics. An 'X-Plane' is an experimental or research aircraft designed to explore the boundaries of aeronautical science, and the term has become shorthand for any development model, research aircraft, or technology demonstrator. Fuelled by the desire to conquer the unknown, the aviation industry has created some of the most remarkable and spectacular aircraft ever to fly, including rocket-powered spacecraft, vertical take-off aeroplanes, giant transporters, and experimental rotorcraft. X-planes are by no means exclusively military. In just over a century, civilian engineers and test pilots have advanced aeronautics from the tentative hops of the Wright Flyer to beyond the atmosphere with the SpaceshipOne, and are certain to go higher, faster, and further.X-Planes and PrototypesJim Winchester is an author of many years' experience who has written widely on various aspects of aviation. He is the author of several books including Fighters of the 20th Century, Combat Legends: A-4 Skyhawk, and Fighter. He contributes to many publications including Air Forces Monthly and Aeroplane. He lives in west London, U.K.