Leonardo da Vinci modeled an ornithopter concept on the flapping wings of bats.
An ornithopter is an aircraft designed to fly by flapping wings rather than using fixed wings or propellers. Leonardo studied birds and bats extensively, examining their wing shapes, joints, feathers, and methods of generating lift.
His flying-machine sketches show a human pilot connected to large wings through a system of levers and pedals. The pilot would have supplied the muscular power, but a person cannot produce enough sustained power to flap wings of the required size. Leonardo’s machine was therefore not a successful aircraft.
The bat comparison is especially important because bat wings are membrane-like and supported by elongated fingers, making them visually closer to some of Leonardo’s proposed surfaces than feathered bird wings. The sketches demonstrate scientific observation as well as imaginative engineering.