Helicopters use rotors to provide lift and thrust, unlike conventional aircraft that use thrust to generate speed, which forces air across their wings to provide lift. The Chinese invented flying tops (small bamboo blades) as toys more than 2,000 years ago but it wasn’t until 1480 that Leonardo da Vinci proposed an aerial screw. This machine generated lift by forcing air downwards through helical blades, but there is no evidence that da Vinci’s design worked in practice. The problem of torque rotating the craft also wasn’t addressed.
In 1754, Russian inventor Mikhail Lomonosov developed a blade attached to a wound up spring but it could only lift small weights. Frenchman Gustave de Ponton d’Amécourt coined the word hélicoptère in 1861 but his steam-powered model couldn’t get off the ground. Italian Enrico Forlanini finally built a working model in 1878. His unmanned vehicle reached a height of 12 metres and hovered for about 20 seconds.
By July 1901, Hermann Ganswindt took to the air in Berlin in what was probably the first powered flight, although Thomas Edison was hot on his heels. Despite coming up with a feasible design with a petrol engine, Edison’s patented machine never flew. Five years later, French brothers Jacques and Louis Breguet built a primitive quadcopter (Gyroplane 1) and took to the air for about a minute, but the craft was so unsteady it had to be tethered. Compatriot Paul Cornu built a twin-rotor device later in the year and flew unaided and un-tethered for 20 seconds.
Several companies then began experimenting with rotor-powered flight, and Raúl Pescara and Étienne Oehmichen were soon trading speed and distance records. By 1932, Russian engineers Boris Yuriev and Alexei Cheremukhin had reached 600 metres. The following year, German manufacturer Heinrich Focke modified an autogyro and built the FW-61. In the United States, Igor Sikorsky decided to use one main rotor for vertical lift and a small tail rotor to counter its torque and the VS-300 became the first practical helicopter. A derivative, the R-4 was the first model to be mass-produced.
The age of the helicopter had arrived.