AIRCRAFT ARMAMENT, the weapons carried on a plane for offensive attack or for defense against enemy aircraft and ground targets. Early warplanes tended to carry either a small-caliber weapon capable of a high number of strikes per second or a larger, slower-firing weapon capable of high penetration and destruction. As technology advanced, aircraft often began to be outfitted with both.
The early, low-powered American fighter aircraft of World War I carried a single drum-fed Lewis gun, which was difficult for the pilot to reload single-handedly. With the development of more powerful aircraft engines and synchronized guns, planes began to be outfitted with twin belt-fed machine guns such as the British Vickers .303 Mk 1. Between the world wars, American fighters carried either two Browning air-cooled .30 caliber machine guns or one .30 and one .50 caliber machine gun. Although aircraft on both sides employed aerial cannon in World War I, the first models that proved to be practical in combat appeared during World War II. The P-39 Airacobra, for example, carried a 37 mm coaxial cannon. The most widely used was the Swiss 20 mm Oerlikon, as carried by the P-38 Lightning. Some B-25 bombers used primarily for attacking ground targets adopted the much larger 75 mm M4 cannon.
Flexible guns mounted to defend heavier aircraft had to remain small and light until engineers developed a new mount that allowed the gunner to overcome slip-stream interference. During and immediately following World War I, standard armament consisted of one or two Lewis guns mounted on a Scarff ring. Enclosed turrets first appeared in 1932 on the B-10 bomber, followed by American adoption of the British power turret, usually mounting twin .50 caliber guns. Remote-controlled turrets came in 1942 and became standard after World War II, as in the retractable twin turrets with 20 mm cannon on the B-36.
By the 1940s, radar-aimed 20 mm cannon had become standard equipment on bombers such as the B-52, while fighter aircraft carried radar-guided and computer-fired air-to-air rockets. The earliest of these was the Folding Fin Aircraft Rocket ("Mighty Mouse") carried by a modified F-86 and heavily used during World War II and the Korean War. Rockets generally replaced guns as the primary fighter weapon, although most fighters continued to carry at least one gun.
Developments in air-to-air ordnance during the 1950s included the infrared-homing Sidewinder missile, the heat-seeking Falcon missiles, and the MB-1 Genie, equipped with a nuclear warhead capable of destroying any aircraft within 1,000 feet of detonation. Gunnery developments included the 20 mm T-171 Vulcan multibarreled cannon capable of firing up to 6,000 rounds per minute. The radar-guided Sparrow missiles and the Phoenix missile, carried by the U.S. Navy's F-14 fighter, were developed during the 1970s.
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