Leonardo da Vinci sketched an ornithopter, a machine with wings intended to flap like a bird’s.
Leonardo closely observed birds and studied how their wings generated lift and thrust. His ornithopter drawings show human-powered mechanisms linking the pilot’s movements to large wings. Some designs used pedals, levers, and ropes to imitate the action of a bird’s muscles and joints.
No Leonardo ornithopter achieved sustained flight. Human muscles cannot provide the same power-to-weight ratio as the flight muscles of birds, and the proposed machines were too heavy and mechanically inefficient. Nevertheless, Leonardo’s anatomical observations and aerodynamic questions made these studies important in the early history of flight.
An ornithopter differs from Leonardo’s aerial screw. The ornithopter relies on flapping wings, whereas the aerial screw uses rotary motion around a central shaft. Modern experimental ornithopters exist, but Leonardo’s versions remained designs and investigations rather than successful aircraft.