III.

History

Jet power as a form of propulsion has been known for hundreds of years, although its use for propelling vehicles that carry loads is comparatively recent. The earliest known reaction engine was an experimental, steam-operated device developed about the first century bc by the Greek mathematician and scientist Hero of Alexandria. Known as the aeolipile, Hero's device did no practical work, although it demonstrated that a jet of steam escaping to the rear drives its generator forward. The aeolipile consisted of a spherical chamber into which steam was fed through hollow supports. The steam was allowed to escape from two bent tubes on opposite sides of the sphere, and the reaction to the force of the escaping steam caused the sphere to rotate.

The development (1629) of the steam turbine is credited to the Italian engineer Giovanni Branca, who directed a steam jet against a turbine wheel, which in turn powered a stamp mill. The first recorded patent for a gas turbine was obtained in 1791 by the British inventor John Barber.

In 1910, seven years after the first flights by the American inventors Orville and Wilbur Wright, the Romanian scientist Henri Marie Coanda designed and built a jet-propelled biplane, which took off and flew under its own power with Coanda as pilot. Coanda used an engine that he termed a reaction motor, but, discouraged by the lack of public acceptance of his aircraft, he abandoned his experiments.

During the next 20 years the gas turbine was developed further in both the United States and Europe. One result of the experimental work of that period was the perfection in 1918 of a turbosupercharger driver by an exhaust gas turbine for conventional aircraft engines. In the early 1930s many patents covering gas turbines were awarded to a number of European engineers. The patent granted the British aeronautical engineer Sir Frank Whittle in 1930 is generally conceded to have outlined the first practical form of the modern gas turbine. In 1935 Whittle applied his basic design to the development of the W-1 turbojet engine, which made its first flight in 1941.

Meanwhile, the French aeronautical engineer René Leduc had exhibited (1938) a model of the ramjet in Paris, and a jet airplane that was powered by an axial-flow turbojet designed by the German engineer Hans Joachim Pabst von Ohain made its first flight in 1939. In the following year, under the direction of the aeronautical engineer Secundo Campini, the Italians developed an airplane powered by a turboprop engine with a reciprocating-engine-driven compressor. The first American-built jet airplane, the Bell XP-59, was powered by the General Electric 1-16 turbojet, adapted from Whittle's design in 1942. The first jet engine of exclusively American design was produced by Westinghouse Electric Corp. for the U.S. Navy in 1944.

From a principle first described in 1906, the pulse jet was developed by the German engineer Paul Schmidt, who received his first patent in 1931. The V-1, or buzz bomb, first flown in 1942, was powered by pulse jet. Also in the mid-1940s the first commercial airline flights using turboprop engines occurred. In 1947 the Bell X-1 experimental airplane, powered by a four-chambered liquid-rocket engine and carried to the stratosphere in the belly of a bomber for launching, was the first pilot-operated craft to break the sound barrier. Subsequently the Douglas Skyrocket experimental airplane, powered by a jet engine in addition to a liquid-rocket engine, broke the sound barrier at low altitude after taking off under its own power.

The first commercial jet airplane, the British Comet, was flown in 1952, but this service was stopped after two serious accidents in 1954. In the U.S., the Boeing 707 jet was the first jet airplane to be tested commercially, in 1954. Commercial flights began in 1958.

The continuous development of jet propulsion for air power has resulted in such advances as piloted aircraft capable of attaining speeds several times greater than the speed of sound, and intercontinental ballistic missiles and artificial satellites launched by powerful rockets.