I am well convinced that Aerial Navigation will form a most prominent feature in the progress of civilization.
George Cayley
Sir George Cayley was an English pioneer of aerial navigation and aeronautical engineering and designer of the first successful glider to carry a human being aloft. He is one of the most important people in the history of aeronautics.
Cayley’s contribution to the history of manned flight is so important that he is recognized by many as “The Father of Aeronautics”. He has also been called the world’s first aeronautical engineer. As early as 1799, he had grasped the basic issue of heavier than air flight, that lift should balance weight and thrust must overcome drag, which should be minimized. His summary was presented in his treatise on the flight, On Aerial Navigation, published in the early years of the 19th century: “the whole problem is confined within these limits, viz, to make a surface support a given weight by the application of power to the air.” Cayley had identified and defined the four forces acting on an airplane in flight: lift, weight, thrust, and drag.
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) revealed that even at school Cayley was developing his ideas on the theories of flight. It has been claimed that these images indicate that Cayley identified the principle 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 weight.
“About 100 years ago, an Englishman, Sir George Cayley, carried the science of flight to a point which it had never reached before and which it scarcely reached again during the last century.”
Wilbur Wright, 1909.
Cayley knew by then that manpower alone would never be sufficient to successfully fly an aircraft. However much the “make a big set of wings and flap them like hell” school of flying, as portrayed by Jacob Degen (who cheated with a hydrogen balloon) believed (or pretended to believe), that flapping was the answer, Cayley knew otherwise. He turned his attention to the issue of power for fixed-wing aircraft that was heavier than air.
He suggested that a more practical engine might be made using gaseous vapors rather than gunpowder, thus foreseeing the modern internal combustion engine. He also contributed in the fields of prosthetics, air engines, electricity, theatre architecture, ballistics, optics, and land reclamation, and held the belief that these advancements should be freely available.
According to the Institution of Mechanical Engineers, George Cayley was the inventor of the hot air engine in 1807: “The first successfully working hot air engine was Cayley’s, in which much ingenuity was displayed in overcoming practical difficulties arising from the high working temperature.” His second hot air engine of 1837 was a forerunner of the internal combustion engine.

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Cayley’s long term vision in regards to air travel
“I may be expediting the attainment of an object that will in time be found of great importance to mankind; so much so, that a new era in society will commence from the moment that aerial navigation is familiarly realised. . . . I feel perfectly confident, however, that this noble art will soon be brought home to man’s convenience, and that we shall be able to transport ourselves and our families, and their goods and chattels, more securely by air than by water, and with a velocity of from 20 to 100 miles per hour.”
George Cayley