It seems like since the beginning of time, man has always been intrigued by the idea of flight, more specifically, the idea of flapping flight seen in birds. Birds seem to fly with little to no effort so it is not surprising that the earliest designs in flight would emulate birds.
The first writings on trying to use the idea of flapping flight date all the way back to the 4th century BC in the epic Ramayana, but there were not any recorded designs made from the descriptions in the writing. The first person to research the flight of birds in depth was a legend of the Renaissance, Leonardo da Vinci. He began studying the flight of birds in the late 15th century and designed sketches a model known as the ornithopter, which in Greek means “bird wing”. The ornithopter would later be used for inspiration for the design of the helicopter.
The sketches of the ornithopter made by da Vinci used a system of pulleys and gears powered by the arms and legs that would make the wings move in the fashion that a bird’s wing does. Da Vinci’s design was not based on an idea of having a wing attached to each arm of a human and having that person flapping their arms up and down because he discovered that humans were not strong enough to generate the power needed to fly. The amount of lift needed to put a human in the air was physically impossible to achieve so the lift to drag ratio compared to that of a bird was much too small due to the lack of lift generated. The only way to overcome that factor was to add the system of pulleys that would multiply the force exerted by the human’s arms and legs and transfer that power to the wings to make them flap fast enough to generate the lift needed to fly. Da Vinci did not make a full scale model of his design, but many other future innovators in flight would try to perfect da Vinci’s design and build a machine that would allow humans to fly through the phenomenon of flapping flight.