The first helicopter can be traced back hundreds of years. In the early fourteenth century, the Chinese made toy flying tops that consisted of four rotor blades attached to a spindle. String was wound on the spindle, and, when pulled, sent the rotors spinning upward. In the sixteenth century, Leonardo da Vinci drew sketches of a flying machine with a twisting screw-like wing and an on-board power source. In 1784, two Frenchmen, Launoy and Bienvenu, gained widespread attention with a twin-rotor helicopter model operated by a spring -bow mechanism. Inventors experimented with helicopter designs throughout the nineteenth century but were unable to come up with an engine that was light-weight yet powerful enough to lift a full-size helicopter off the ground.

In the early 1900s, with the invention of the gasoline engine, new possibilities opened up for helicopter flight. In 1907, French inventor Louis Bréguet (1880-1955) achieved the...