Flight can be traced back as far as 400 B. when Archytas, a Greek scholar, built a wooden pigeon that moved through the air. Several inventors made many attempts at flight but none succeeded. Such attempts include the omithopter, which was a machine that created lift by moving wings and caused propulsion with a propeller attached to the backed and was originally designed by Leonardo de Vinci but never succeeded in full flight. It was later stated that man's muscles simply did not have the power needed to move aeronautical equipment fast enough to achieve flight, that a person would have to have the ability to increase their heart rate up to 800 beats per minute such as a bird to create the lift needed to fly. In 1804 a British inventor named George Cayley built the first glider that carried his coachman across a valley but he could not achieve control of the flight direction. As years went on inventors created the first powered planes but were never successful in flight and typically gave up their attempts after one or two tries. After reading of Lilienthal's gliding flights in Germany, the Wright brother's vowed to continue his work after his death. Unable to find an engine manufacturer to meet their specifications of 8 horsepower and engine weight of less than 200 pounds, they decided to design and build their own engine. Aided by their bicycle mechanic Charlie Taylor, they were able to build an engine that produced 12 horsepower. With the engine built, they then faced the problem of how to build a propeller since very little was known on the subject. Surprisingly, with their previously collected wing data, they were able to build accurately the engine propellers. Using the basic airframe of their 1902 Glider, the Kitty Hawk Flyer was born. When the Wright brothers had made the final altercations they decided to test out the flyer. They had a coin toss to see who would be the tester and Wilbur won.