Though the first actual helicopter wasn’t built until the 1940s, it is believed that Leonardo da Vinci’s sketches from the late fifteenth century were the predecessor to the modern day flying machine. As with many of da Vinci’s ideas, he never actually built and tested it – but his notes and drawings mapped out exactly how the device would operate.
Da Vinci scrawled next to his sketches of the screw-like machine the following description: "If this instrument made with a screw be well made – that is to say, made of linen of which the pores are stopped up with starch and be turned swiftly, the said screw will make its spiral in the air and it will rise high."
Also known as the "Helical Air Screw" or simply the "airscrew", the device was designed to compress air to obtain flight – similar to today’s helicopters. Da Vinci was a big proponent of the many possibilities offered by the screw shape, and he used the shape for other inventions and designs as well.
Da Vinci’s helicopter measured more than 15 feet in diameter and was made from reed, linen and wire. It was to be powered by four men standing on a central platform turning cranks to rotate the shaft. With enough rotation, da Vinci believed the invention would lift off the ground. Unfortunately, due to weight constrictions, modern scientists do not believe da Vinci’s invention would have been able to take flight.