Graziano & Raulin
Research Methods (9th edition)
George Cayley (1773-1857) was an English baronet, who became interested in the possibilities of aviation.
Cayley was well aware of the successes of balloonists since 1783 when, in a hot air balloon designed and built by the Montgolfier brothers in France, two men were the first humans to fly through the air. After that, larger balloons were built, capable of carrying more people. Hydrogen gas rather than hot air was used for lift, and steam-powered engines were eventually added to provide forward thrust.
Cayley was among a number of persons who saw serious limitations in balloon flight, and searched for ways to build successful heavier-than-air machines. Cayley built and flew models and full-size gliders, but never flew in them. He established the “fixed wing” concept for aircraft, a major departure from flapping-wing (ornithopter) contrivances.
In 1804, Cayley wrote Essay upon the Mechanic Principles of Aerial Navigation and, in 1809, published his important work, On Aerial Navigation. He later published descriptions of a future flying machine, including its lift surfaces, stabilizer, engine, and propeller. Shortly before he died in 1857, Cayley had worked out the mathematical and aerodynamic principles of heavier than air flight, and built the first full-sized glider designed to carry a person. However, it does not appear ever to have been flown.
Steam engines were available for propulsion, but were too heavy to work in flying machines. No engine suitable to power an airplane was available in Cayley’s time. It would not be until 1876, nine years after Cayley’s death, that the first practical gasoline engine was produced (by A. N. Otto in Germany). That engine was the prototype for later successes, such as those of the Wright brothers.