Just watching birds effortlessly flitting through the air makes me want to mount up on wings as the eagle. Apparently I am not the only one, nor the first with the desire. The first successful manned flights were in hot air balloons. But the monstrous lighter-than-air machines certainly didn’t flit. A dozen or so years later Sir George Cayley studied the birds carefully and discovered four important aerodynamic forces of flight: weight, lift, thrust, and drag. He correctly determined that birds got both lift and thrust from their wings to carry their weight and overcome drag. From well before Cayley’s day until even now, inventors have been designing and testing a type of flapping wing contraption called an “ornithopter,” trying for human-powered flight that would mimic the action of birds. The reason we don’t see any ornithopters in common use is that humans have too much weight and not enough power to develop the lift and thrust that birds do with their favorable power to weight ratios.
Otto Lilienthal
Otto Lilienthal is called the first true aviator because he actually launched himself into the air, “flew,” and landed safely enough to tell about it – many times. His was lifetime committed to carefully studying bird flight to figure out what their design secrets were. After crashing three ornithopters, he turned to building gliders. Beginning in the early 1890’s Lilienthal built 18 gliders (uch like today’s hang gliders) and many monoplanes and biplanes. It was in one of these early gliders that he had his first successful flight. Then August 9, 1896, his glider lost lift and crashed from a height of more than 50 feet. He died the following day.
The Wright brothers, who credited Lilienthal with the inspiration to figure out how to fly, continued their study of bird flight, made glider experiments, conducted wind tunnel tests, and employed their knowledge of engineering to build the first successful flying machine. On December 17, 1903, theirs were the first manned powered flight – four of them, each under 60 seconds.