Sir George Cayley (1773-1857),English flight pioneer and aerodynamicist. Cayley spent much of his life engaged in his own experiments,devoting himself to the study of flight. In 1808,he built and flew a large glider,thought to be the first heavier-than-air machine ever flown. He built and tested a variety of designs,including flapping- wing ornithopters,and bi- and triplanes. He realised that stability and control were derived from the horizontal and vertical surfaces of an aircraft's tail,and that a lightweight propeller could be used to power an aircraft. In 1853,his coachman flew across a valley in one of his gliders,the first manned glider flight |