Leonardo da Vinci designed an ornithopter, a machine intended to fly by flapping wings like a bird.
Leonardo made extensive observations of birds and bats and recorded his ideas about flight in notebooks, especially during the late fifteenth and early sixteenth centuries. His proposed machines generally used a human operator to move large wings through pedals, levers, and other mechanical linkages. Some designs placed the pilot in a prone position so the body could operate the wing mechanisms.
No Leonardo ornithopter is known to have flown, and human muscles cannot produce enough sustained power for a machine of the proposed size. The designs nevertheless show his attempt to connect anatomy, mechanics, and observation of nature. An ornithopter is different from the aerial screw: the former uses flapping wings, while the latter uses a rotating helical surface. Modern experimental ornithopters have flown, but they use lightweight materials and carefully engineered power systems rather than Leonardo’s proposed human-powered arrangements.