The first jet engine to run refused to stop when its fuel was cut
On 12 April 1937, Frank Whittle's team started the Power Jets WU, the first turbojet ever to run. It promptly sped up out of control, even after the fuel was shut off. Near panic followed. The culprit turned out to be fuel that had leaked into the combustion chamber during checks and pooled there, burning until it was gone.
Whittle had been at it for years. As a cadet at RAF College Cranwell he formally put his turbojet idea to his superiors in 1928 and filed his first patent on 16 January 1930. The government showed little interest, and progress was slow. Hans von Ohain took out a German patent on a comparable design in 1935, and his axial-flow approach, rather than Whittle's centrifugal compressor, eventually became the industry norm. A Frenchman, Maxime Guillaume, had patented a gas-turbine aircraft engine as early as 1921, but compressors of the day could not make it work.
Von Ohain's engine flew first. On 27 August 1939 the Heinkel He 178, piloted by Erich Warsitz, became the first aircraft propelled by a turbojet, and Britain's first jet flight came in 1941. The basic principle is simple: a compressor squeezes incoming air, fuel burns in it, the hot gas spins a turbine that drives the compressor, and whatever energy remains leaves through a nozzle as a fast jet.
Materials were the real bottleneck. Early non-British engines needed overhauls every 10 or 20 hours because turbine blades crept and failed, while British engines using Nimonic alloys lasted far longer; by 1949 the de Havilland Goblin was type-tested for 500 hours without maintenance. For airlines, jets proved so dependable, with some exceeding 99.9 percent dispatch reliability, that two- and three-engine airliners and more direct ocean routes became possible.
Turbojets are wasteful at low speeds, so most aircraft moved on to turbofans. They survived where sustained supersonic flight mattered, most famously in Concorde's Olympus 593. At Mach 2, Concorde's intake did far more squeezing than the engine itself: 63 percent of total compression against 8 percent from the compressor.
Source: Turbojet
