Leonardo da Vinci sketched an ornithopter, a flying machine intended to rise by flapping wings inspired by birds and bats.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo studied bird anatomy, wing movement and the flow of air in numerous notebooks. His proposed machines generally used a human operator’s arms and legs to power large wings through a system of levers, cables and pedals.
Leonardo’s ornithopters were never proven capable of carrying a person in sustained flight. Human muscles cannot deliver the power-to-weight ratio needed for bird-like flapping flight with the materials available to him. His designs nevertheless anticipated the later scientific study of aerodynamics and mechanical flight.
An ornithopter is not the same as a helicopter or an airplane. Modern ornithopters, including small remotely controlled models, use motors to flap wings. Leonardo’s drawings also included gliding and screw-based concepts, so not every flying-machine sketch in his notebooks was an ornithopter.