Leonardo da Vinci’s ornithopter was a proposed flying machine powered by flapping wings inspired by birds.
Leonardo studied bird anatomy and flight for decades, producing many sketches of wings, joints, and control systems. His ornithopter designs attempted to reproduce the up-and-down motion of a bird’s wings with a human-operated mechanism. Some versions placed the pilot in a prone position and used pedals, levers, or hand controls to move the wings.
No Leonardo ornithopter is known to have flown. Human muscles cannot supply the power-to-weight ratio needed to flap wings of the proposed size, and the machines lacked a sufficiently light engine. Leonardo eventually recognized that gliding and the study of air currents offered more realistic paths than purely human-powered flight.
An ornithopter is not the same as an airplane, helicopter, or parachute. It is defined by flapping wings. Modern experimental ornithopters have flown with engines or small mechanical systems, but those successes do not establish that Leonardo’s full-scale designs were practical.