The Engine That Reinvented Flight: How the Jet Was Born Twice

For the first four decades of powered flight, every airplane was pulled or pushed through the air by a propeller spun by a piston engine. The propeller has a hard ceiling: as its tips approach the speed of sound, efficiency collapses, capping how high and fast an aircraft can practically fly. Breaking past that ceiling required a fundamentally different way to make thrust. The answer — the gas-turbine jet engine — was invented twice, independently, by two men who never collaborated. In England, Royal Air Force officer Frank Whittle patented a turbojet design in 1930 and ran a working engine on a test stand in 1937, fighting official indifference for years. In Germany, physicist Hans von Ohain developed his own turbojet at almost the same time; his engine powered the Heinkel He 178, the world's first jet-powered flight, in August 1939. The principle is elegant: a compressor squeezes incoming air, fuel is burned in that compressed air, and the hot, high-energy exhaust both spins a turbine (which drives the compressor) and blasts rearward to produce thrust — Newton's third law made into propulsion. With no propeller tips to limit it, the jet could fly higher, where thin air means less drag, and far faster. The consequences were total. Within two decades the jet transformed military aviation and then civil travel, giving rise to the swept-wing airliners that shrank the world. Nearly every airliner, business jet, and military fast-jet flying today is a descendant of those two secret engines built on the eve of a war.