Kitabı oku: «Story of the Aeroplane»

The Ocean of Air

Around the dry land of the earth are the oceans of water. We may never have seen them, but we have knowledge of them and their navigation, and their names suggest very definite and concrete objects of thought. We sometimes do not realize, however, that we live and move and have our being at the bottom of a vaster and deeper ocean that covers to a depth of many miles the whole earth, and to the surface of which man nor beast nor bird has ever ascended; an ocean with currents and whirlpools and waves of more than mountain height; an ocean in which we are as much at home as are the finny tribes and the monsters of the deep in their watery caverns. This is the ocean of the air. We are about to consider man’s efforts to rise from the bottom of this ocean and wing his flight a little way through the atmosphere above him. His excursions upward are limited, for he could not live near the surface heights of this ocean, vast and deep and boundless. The art and science of his flight through the air, because of its relation to the flight of birds, we call aviation. (Avis: Latin, a bird.)

Early Attempts at Aviation

“The birds can fly and why can’t I?”

This query of Darius Green’s, in various forms, has suggested itself to man since the dawn of history. Born with an inspiration to look upward and aspire, the navigation of the air has appealed with peculiar force to his imagination and through the centuries has at different times led bold and adventurous spirits to attempt what the world long regarded as impossible. The heavens seemed reserved for winged insects, birds and angels. Audacious man might not venture out upon the impalpable air. Can man fly? After more than four thousand years it was left for man to answer yes, to rise from the earth on wing and thrill the world “with the audacity of his design and the miracle of its execution.” Bold enterprise! Fitting achievement to usher in a new century! A seeming miracle at first, but destined soon to excite no more curiosity than the flight of bees and birds. The solution of the problem of human flight was no miracle nor was it the swift work of genius accomplished at a magic master stroke. It was the result of intelligence and industry patiently applied for years till the barriers of difficulty gave way and man ventured out with assurance on the highways of the air.

Just when he first attempted to fly is not known. Ancient Greek mythology abounds in stories of flying gods and mortals. Kites which bear some relation to the aeroplane were toys among the Chinese thousands of years ago. A Greek by the name of Achytes is reported to have made a wooden dove which flew under the propelling power of heated air. Baldad, a tribal king in what is now England, so tradition has it, attempted to fly over a city but fell and broke a leg. A similar accident is said to have happened to a Benedictine monk in the eleventh century and to others attempting like exploits in after years. A fall and a broken leg seem to have been the usual results of these early attempts at aerial flight.

In the fifteenth century students and inventors gave serious attention to the navigation of the air and trustworthy accounts of their labors come down to us. Jean Baptiste Dante, a brother of the great Italian poet, made a number of gliding flights from high elevations and while giving an exhibition at a marriage feast in Perugia, like his predecessors in the middle ages, alighted on a roof and broke a leg. Leonardo da Vinci, the great painter and sculptor, was an amateur aviator of no mean attainment for his day. He invented a machine which the operator was to fly by using his arms and legs to set wings into flapping motion, like those of birds. This was called an orthopter, or ornithopter, a name which may be properly applied to any similar device. Another machine invented by him was in the form of a horizontal screw ninety-six feet in diameter. By the twisting of this the machine was designed to fly upward. This was called a helicopter. Da Vinci’s third invention in this line was the parachute, with which successful descents were made from towers and other elevations. In the early half of the eighteenth century the Swedish philosopher, Emanuel Swedenborg, sketched in one of his works a flying machine of the orthopter style which he knew would not fly but which he suggested as a start, saying “It seems easier to talk of such a machine than to put it into actuality, for it requires greater force and less weight than exists in the human body.”

In 1742 the Marquis di Bacqueville at the age of sixty-two attempted to make a gliding flight from the tower of his home in Paris across the river Seine to the gardens of the Tuileries, started successfully in the presence of a great multitude, but suddenly halted over the river and fell into a boat, paying the historic penalty of a broken leg.

At this point it may be well to classify the flying devices thus far considered.

Early Flying Machines

1. The orthopters, or as they are less commonly called, the ornithopters. The word “orthopter” means straight wing and the word “ornithopter” bird wing. This class of machines includes those designed to fly by the flapping of wings, somewhat in imitation of birds.

2. The helicopters. The word “helicopter” means spiral wing. Flying machines of this class are designed to fly by the rapid horizontal rotation of two spiral propellers moving in opposite directions but so shaped that their combined effect is to move the machine upward. They are like a pair of tractor propellers of the modern aeroplane but arranged horizontally to lift the machine instead of drawing it forward in a vertical position.

3. The gliders. As the name suggests, these were designed to coast or glide down the air, to start from a high elevation and by sailing through the air in an oblique direction reach a lower elevation at some distance from the starting point. Down to the latter part of the nineteenth century only the gliders were successfully used in man flight. In reality they can scarcely be called flying machines for they could not lift their own weight, though late experiments prove that when once in air they may rise above their starting point under the influence of a strong wind. The glider, however, performed a most important part in the evolution of the aeroplane. In coasting the air from hills, sand dunes and towers against steady wind currents a number of inventors through a series of years learned how to guide and control these gliders in their downward flight-an essential preparation for the application of motive power to lift the glider against the force of gravity and thus make it a veritable flying machine or aeroplane.