George Cayley - Flying Machines

Flying Machines

He is mainly remembered for his pioneering studies and experiments with flying machines, including the working, piloted glider that he designed and built. He wrote a landmark three-part treatise titled "On Aerial Navigation" (1809–1810), which was published in Nicholson's Journal of Natural Philosophy, Chemistry and the Arts. The 2007 discovery of sketches in Cayley's school notebooks (held in the archive of the Royal Aeronautical Society Library in London, England) reveal that even at school Cayley was developing his ideas on the theories of flight. It has been claimed that these images indicate that Cayley modeled the principles of a lift-generating inclined plane as early as 1792. To measure the drag on objects at different speeds and angles of attack, he later built a "whirling-arm apparatus", a development of earlier work in ballistics and air resistance. He also experimented with rotating wing sections of various forms in the stairwells at Brompton Hall. These scientific experiments led him to develop an efficient cambered airfoil and to identify the four vector forces that influence an aircraft: thrust, lift, drag, and gravity. He discovered the importance of the dihedral angle for lateral stability in flight, and deliberately set the centre of gravity of many of his models well below the wings for this reason; these mechanics influenced the development of hang gliders. As a result of his investigations into many other theoretical aspects of flight, many now acknowledge him as the first aeronautical engineer. His emphasis on lightness led him to shift the forces in the landing gear wheel from compression to tension by using string as wires, in effect re-inventing the wheel. This wire wheel principle was (and is) later used by others for bicycles, cars and many other vehicles.

The model glider successfully flown by Cayley in 1804 had the layout of a modern aircraft, with a kite-shaped wing towards the front and an adjustable tailplane at the back comprising horizontal stabilisers and a vertical fin. A movable weight allowed adjustment of the model's centre of gravity. Around 1843, he was the first to suggest the idea for a convertiplane, an idea which was published in a paper written that same year. During some point prior to 1849 he designed and built a biplane in which an unknown ten-year-old boy flew. Later, with the continued assistance of his grandson George John Cayley and his resident engineer Thomas Vick, he developed a larger scale glider (also probably fitted with "flappers") which flew across Brompton Dale in 1853. The first adult aviator has been claimed to be either Cayley's coachman, footman or butler: one source (Gibbs-Smith) has suggested that it was John Appleby, a Cayley employee—however there is no definitive evidence to fully identify the pilot. An obscure entry in volume IX of the 8th Encyclopædia Britannica of 1855 is the most contemporaneous account with any authority regarding the event. A 2007 biography of Cayley (Richard Dee's The Man Who Discovered Flight: George Cayley and the First Airplane) claims the first pilot was Cayley's grandson George John Cayley (1826–1878). Dee's book also reports the re-discovery of a series of sketches from Cayley's school exercise book which suggest that Cayley's first designs concerning a lift-generating inclined plane may have been made as early as 1793.

A replica of the 1853 machine was flown at the original site in Brompton Dale by Derek Piggott in 1973 for TV and in the mid-1980s for the IMAX film On the Wing. The glider is currently on display at the Yorkshire Air Museum. Another replica, piloted by Allan McWhirter, flew in Salina, Kansas just before Steve Fossett landed the Virgin Atlantic GlobalFlyer there again in March 2003, and later piloted by Richard Branson at Brompton in summer 2003.