THE first scientist who paid serious attention to the problems of mechanical flight and who tried to explain in mathematical terms the fundamental principles of mechanical flight was Sir George Cayley. He was born in 1773, and his interest in aeronautics was inspired in his boyhood by the Montgolfiers’ achievements with the balloon.
A man of many activities, Sir George Cayley was chiefly interested in science and engineering; and he brought to aeronautics the results of his experience in these two activities. He recognized with remarkable acumen many principles which ultimately became established practice. His first experiments with the Chinese or aerial top, for example, produced important contributions to the theory of the airscrew. He made the first complete and thorough study of lighter-than-air flight, and made what were perhaps the first serious contributions to mechanical flight.
His statement that “to make a surface support a given weight by the application of power to the resistance of the air” proves not only that he foresaw the aeroplane but also how clearly he appreciated principles which, although commonplaces later, were then undeveloped.
Perhaps the most remarkable example of his vision was his ability to foresee airships and aeroplanes. Although he made contributions of outstanding importance to mechanical flight (a term he used in relation to that branch of aeronautics which developed into the aeroplane), and although he is more commonly associated with mechanical flight, Cayley himself believed that the future of aviation depended on the airship, or, as he described it, the navigable balloon. That his early ideas were sound, and that he foresaw to a remarkable degree the later design of airships, can be seen from the accompanying illustration. This shows his first design for a navigable balloon.
DESIGN FOR A NAVIGABLE BALLOON produced in 1816-17 by Sir George Cayley. The balloon was based on the Montgolfiers’ hot air principle. It was 300 feet long, 45 feet high and 90 feet wide. Driven by a steam engine, the balloon had a possible speed in still air of fifteen miles an hour.
This design was produced in 1816-17. The Montgolfiers still influenced him, for this balloon was based on the Montgolfiers’ hot air principle. The balloon was 300 feet long, 45 feet high and 90 feet wide. It could be driven by a steam engine at fifteen miles an hour, and could carry a crew of seven.
This design was a natural evolution from his experiments with the conventional type of balloon. He maintained that the spherical form of the balloon should be lengthened horizontally, thus diminishing the cross-section. He was probably the first man to realize that it was essential to divide the gas into separate compartments. He anticipated a rigid structure, which he thought necessary to guard against what were then unknown laws of resistance.
Although he believed that the future of aeronautics depended on the airship, or navigable balloon, Cayley believed also that the airship and the aeroplane would be complementary to each other. Because of their buoyancy, large elongated balloons, he said, could carry a considerable cargo and thus offer greater facilities than mechanical means alone for transporting men and goods through the air. “Mechanical flight,” he wrote in 1843, “seems more adapted for use on a much smaller scale, and for less remote distances; serving, perhaps, the same purpose that a boat does to a ship, each being essential to the other”. The later history of the airship shows this statement to have been another example of Cayley’s vision.
From his early experiments in mechanical flight he obtained information about the resistance of different-sized surfaces moving at certain velocities. From these researches he experimented with a glider which was said to have had an area of 300 square feet. According to Cayley’s theories this glider, when carried forward against a light breeze, could be raised from the ground for several yards. These gliding experiments were apparently made without any human load, but there seems to have been a rudder which could be set to determine the angle of descent.
Cayley saw the future of aeronautics not in terms of separate experiments, nor as something to be taken step by step. He looked ahead, beyond his own times. It is true that he neglected certain factors which were vital links in the chain that led to the future he foresaw, but for the most part he was able to see aeronautical development in large sections rather than in single steps. Having, for example, experimented with his glider, he went farther ahead and studied the means of propulsion. He considered the type of steam engine invented by Boulton and Watt and the crude form of internal combustion engine with which experiments were being made at that time. Even then, he seems instinctively to have known that the internal combustion engine was the more suitable.
Sir George Cayley died in 1857. A distinguished engineer and scientist, he received too little credit in his lifetime for his contributions to aeronautics. Much of his work was ignored until years after his death; and when he was alive he protested against the very neglect from which his own work was to suffer. He complained that certain published experiments which preceded his own had been neglected to such an extent that each inventor had to take up the threads for himself, and that the progress of aeronautical science thereby lacked the continuity that was vital to it.