"The idea of a vehicle that could lift itself vertically from the ground
and hover motionless in the air
was probably born at the same time that man first dreamed of flying."
Igor Sikorsky, helicopter pioneer.
Leonardo da Vinci (born in Italy in 1452) was blessed with an encyclopedic knowledge of invention, science, music, engineering and many other areas, including human-powered flight. Also an accomplished artist (Mona Lisa comes to mind), da Vinci drew sketches of human-powered flying machines, one of which was an "aerial screw" operated by four men running on a turntable.
Long before Sir Isaac Newton propounded his laws of motion, Leonardo's intellect may have led him to conclude that the surfaces of his spiral flyer would produce the reactive force that was eventually labeled "lift." Considering the very low density of the atmosphere, there was no way those four athletes could move enough air to lift men and machine off the ground; nevertheless, da Vinci's aerial screw was a logical, if not practical, step in the right direction.
