An ornithopter (from Greek ornis, ornith- "bird" and pteron "wing") is an aircraft that flies by flapping its wings. Designers sought to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, they are usually built on the same scale as flying animals. Larger, crewed ornithopters have also been built and some have been successful. Crewed ornithopters are generally either powered by engines or by the pilot. Early history Some early crewed flight attempts may have been intended to achieve flapping-wing flight, but probably only a glide was actually achieved. They include the purported flights of the 11th-century Catholic monk Eilmer of Malmesbury (recorded in the 12th century) and the 9th-century poet Abbas Ibn Firnas (recorded in the 17th century). Roger Bacon, writing in 1260, was also among the first to consider a technological means of flight. In 1485, Leonardo da Vinci began to study the flight of birds. He grasped that humans are too heavy, and not strong enough, to fly using wings simply attached to the arms. He, therefore, sketched a device in which the aviator lies down on a plank and works two large, membranous wings using hand levers, foot pedals, and a system of pulleys. In 1841, an ironsmith kalfa (journeyman), Manojlo, who "came to Belgrade from Vojvodina", attempted flying with a device described as an ornithopter ("flapping wings like those of a bird"). Refused by the authorities a permit to take off from the belfry of Saint Michael's Cathedral, he clandestinely climbed to the rooftop of the Dumrukhana (import tax head office) and took off, landing in a heap of snow, and surviving. The first ornithopters capable of flight were constructed in France. Jobert in 1871 used a rubber band to power a small model bird. Alphonse Pénaud, Abel Hureau de Villeneuve, and Victor Tatin, also made rubber-powered ornithopters during the 1870s. Tatin's ornithopter was perhaps the first to use active torsion of the wings, and apparently it served as the basis for a commercial toy offered by Pichancourt 1889. Gustave Trouvé was the first to use internal combustion, and his 1890 model flew a distance of 80 meters in a demonstration for the French Academy of Sciences. The wings were flapped by gunpowder charges activating a Bourdon tube. From 1884 on, Lawrence Hargrave built scores of ornithopters powered by rubber bands, springs, steam, or compressed air. He introduced the