Sir George Cayley is sometimes called the father of aeronautics. His contributions are mostly obscure, if nothing else because he came of age when the science of aerodynamics bordered the ludicrous in public’s estimation. It was the age of Bonaparte, and Europe was concerned with more earthly matters.
His was also the time when the industrial revolution began, and there was still shortage of knowledge in propulsion systems. Besides, his achievements remained dormant for over half a century before being considered again by modern age pioneers, such as Lilienthal, Lanchester and the Wright Brothers. However, Cayley’s writings clearly demonstrate that he had grasped fundamental concepts well ahead of anybody else. For example, writing about lift
He investigated the lift of cambered wings and the movement of the center of pressure. This led to understanding that a region of low pressure is established on the upper side of the wing.
Cayley’s lifetime achievements are discussed concisely by CH Gibbs-Smith. His ideas spanned from helicopters to airships, from kites to birds, but his name is not formally linked to any of the aerodynamics advances, and certainly he was in no way able to build a heavier-than-air flying machine. Yet, it is also recognized that he made fundamental discoveries by great reasoning and imagination, such as :
Many of his contributions remained in the form of drawings and hand sketches. These included “inventions” such as the tandem wing configuration, the convertiplane, the helicopter with two counter-rotating propellers. He did devise methods for testings airfoils at angle of attack, and he built and tested several unmanned gliders.
His experimemtal system consisted of a whirling arm (the precursor to the modern wind tunnel) to measure the drag and lift of various airfoils. The hirling arm was 5 feet long (about 1.65 m) and attained tip speeds between 10 and 20 feet per second (3.3-6.6 m/s).
Fig. 1 below shows a drawing of an airfoil (streamlined body) based on the contour of a trout. This idea failed to influence later scientists, until aerodynamic theories in the early 20th century evidenced the benefits of thick airfoil sections. (This shape is not too different from a symmetrical NACA airfoil).
Figure 1: Streamlined body based on the shape of a trout.
Cayley’s life was the subject of at least two biographies (listed below). His
private journals are the most important source of his thinking. These became
available to the public through the Royal Aeronautical Society some seventy
years after his death. Some of his fundamental discoveries were published in the