Helicopter will take to the air

Leonardo da Vinci : Artist
Leonardo’s helicopter was designed as a human powered machine. Unfortunately for Leonardo, engines had not been invented yet and humans have nowhere near the power to weight ratio required for them to produce enough energy to lift themselves against the force of gravity.
It was designed to work by having two men standing in the central circular platform. Each man would take hold of a wooden shaft and walk around the central shaft. This would rotate the “blades” of the helicopter and supposedly produce flight.