Windswept_ The Story of Wind and Weather - Marq de Villiers [115]
Leonardo's sketchbooks show many gliding devices, most of them winglike objects strapped to a human body, looking curiously like modern hang gliders. In this as in many other things, Leonardo was precocious, and not much progress was made for another four hundred years or so. In the early nineteenth century George Cayley designed and built the first true glider, a small biplane made of cloth sails with a horizontal tail and two lateral fins. One of his designs carried a man about 900 feet.7 All through the nineteenth century the occasional dreamer attached wings to his body and leapt off a building, and occasionally survived; but hang gliding as a sport had to wait until the twentieth century, when NASA engineer Francis Rogallo and his wife built a wind tunnel in their home to develop a personal flying device consisting of a delta-winged sail controlled by ropes. Since then, activities using personal wind-powered devices have proliferated. On the ground, they include soft-winged sail-boards and rigid-winged kitewings (which can reach 24 miles an hour in good conditions), kite surfing, skate sailing, and ice sailing. In the air, parasailing, hang gliding, and wingsailing.
The Chinese were early experimenters with flying techniques. That they invented kites a long time ago, probably before the fifth century B.C., we know because philosopher Mo Zi, who lived between 478 and 392 B.C., made a wooden kite in the shape of a hawk that flew for a whole day. Some reports, dating back much earlier than that, indicate that the Chinese used umbrella-like devices to jump off towers or high mounds. But the first modern parachute descent was in 1783, by French physicist Louis-Sebastien Lenormand, who hurled himself off the tower of Montpellier Observatory and drifted safely to ground. Two years later Jean Pierre Blanchard ascended on high in his balloon, attached a parachute to his dog, and dropped it from several hundred yards. The dog landed safely but was said to have run away and was never seen again.
It was the gliding flight of storks, slow and stately birds, that inspired the first aircraft designs of Otto Lilienthal in the late nineteenth century. Lilienthal, who was one of the inspirations for the Wright brothers, built what he called a sailing apparatus very like the outspread pinions of a soaring bird. "It consists," his notes say, "of a wooden frame covered with shirting (cotton-twill). The frame is taken hold of by the hands, the arms resting between cushions, thus supporting the body. The legs remain free for running and jumping. The steering in the air is brought about by changing the center of gravity. This apparatus I had constructed with supporting surfaces of ten to twenty square meters. The larger sailing surfaces move in an incline of one to eight, so that one is enabled to fly eight times as far as the starting hill is high."
A flight of Otto Lilienthal
Lilienthal's reputation as a respectable scientist at last pushed experimentation with flight beyond the province of dreamers and fools. Over a span of five years he developed eighteen models of gliders, fifteen of them monoplanes and three biplanes. Each was essentially a hang glider, controlled by the pilot shifting his weight. "To invent an airplane is nothing," he once famously said. "To build one is something. But to fly is everything." To facilitate his flights, he built a conical hill in his backyard at Lichterfelde, near Berlin, so he could launch his gliders into the wind no matter which direction it was coming from. Alas, he was a victim of his own experiments, and he died after a crash of one of his hang gliders on August 10, 1896.8
After the Wright brothers, as we know, aviation developed at an extraordinary pace. By 1908, maybe ten people in all the world had been in an airplane. Four years later, literally thousands had flown. At the beginning of the twenty-first century, there were some eight thousand commercial flights aloft at any one