Father of Flight - Flapping Wing

This is a drawing of an experiment to test whether beating wings would raise a heavy load. A 12 metre (40 foot) 'wing', constructed with a net-and-cane framework covered in paper, was intended to be attached to a plank of wood weighing as much as a person. He hypothesised that if the long lever could be swiftly pushed down, the wing would make contact with the air, causing the plank to lift. Success meant elevating both a pilot and their flying apparatus, sustaining them in flight.
In his notebook, Leonardo wrote: ... but be sure that the force is rapid and if the above effect is not obtained, waste no more time on it!