The basic idea of creating motion by directing a jet of fluid in the opposite direction dates back to ancient times. In the 1st Century AD, the Greek mathematician Hero of Alexandria described a device propelled by squirting steam out of two opposing nozzles. But it’s doubtful it ever worked as the jets were probably too weak to overcome friction between its various components. In 1922, French engineer Maxime Guillaume was granted a patent for a simple jet engine. While never built, it had the right idea. It consisted of a series of turbines to compress air, which was then mixed with fuel and ignited. The resulting rapidly expanding gas produced thrust.
The first to succeed in making this approach work was a young RAF engineer named Frank Whittle. In the 1920s, he devised an arrangement of turbines and compressors he claimed would produce enough thrust for aircraft propulsion. The UK Air Ministry disagreed, however, leading him to set up his own company, which created the first working jet engine in 1937. By then, German physicist Hans von Ohain had hit on a similar design, allowing him to beat Whittle to the first actual flight of a jet aircraft – the Heinkel He 178 – in August 1939.