Many consider him to be the first true scientific aerial investigator and the first person to understand the underlying principles and forces of flight and the first man to create the wire wheel.
Among the many things that he developed are self-righting lifeboats, tension-spoke wheels, [11] the "Universal Railway" (his term for caterpillar tractors),[12] automatic signals for railway crossings,[13] seat belts, small scale helicopters, and a kind of prototypical internal combustion engine fuelled by gunpowder (Gunpowder engine).
[14] 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.
"[17] Cayley 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),[18] which was published in Nicholson's Journal of Natural Philosophy, Chemistry and the Arts.
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.
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.
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 principles influenced the development of hang gliders.
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 consisting of horizontal stabilisers and a vertical fin.
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 front of Wydale Hall in 1853.
A replica of the 1853 machine was flown at the original site in Brompton Dale by Derek Piggott in 1973[25] for TV and in the mid-1980s[26] for the IMAX film On the Wing.
The University of Westminster also honours Cayley's contribution to the formation of the institution with a gold plaque at the entrance of the Regent Street building.
[32][33] (J W Clay's expanded edition of Dugdale's Visitation of Yorkshire incorrectly gives the date as 9 July 1795,[34] as does George Cayley's entry in the Oxford Dictionary of National Biography.