Antiaircraft gun

Antiaircraft gun, artillery piece that is fired from the ground or shipboard in defense against aerial attack. Antiaircraft weapons development began as early as 1910, when the airplane first became an effective weapon. In World War I, field artillery pieces up to about 90 mm (3.5 inches) in calibre were converted to antiaircraft use by mountings that enabled them to fire nearly vertically. Aiming methods were inadequate, however, and in the interwar decades great progress was made in the development of range finders, searchlights, time fuzes, and gunlaying mechanisms to help artillery pieces hit the rapidly moving targets presented by aircraft.  In World War II, rapid-firing and automatic antiaircraft guns were introduced, radar was applied to target tracking, and tiny radio-wave proximity fuzes exploded the ammunition as it approached the target. Against dive-bombers and low-level attack aircraft, a 40-millimetre (1.5-inch) gun, first produced by the Bofors firm of Sweden, was widely used by the British and U.S. forces. It fired 2-pound (0.9-kilogram) projectiles to a height of 2 miles (3.2 km) at 120 rounds per minute. The Soviets based their 37-millimetre weapon on this gun. Heavier antiaircraft guns, up to 120 mm, were used against high-flying bombers. The most effective of these was the German 88-millimetre Fliegerabwehrkanone; its abbreviated name, flak, became a universal term for antiaircraft fire. In 1953 the U.S. Army introduced the Skysweeper, a 75-millimetre automatic cannon firing 45 shells per minute, aimed and fired by its own radar-computer system. With the introduction of guided surface-to-air missiles in the 1950s and ’60s, heavy antiaircraft guns such as this were phased out, though radar-guided automatic guns of 20 to 40 mm continued to provide a defense against low-flying aircraft and helicopters.

Attack aircraft

Attack aircraft, also called Ground Attack Aircraft, or Close Support Aircraft, type of military aircraftthat supports ground troops by making strafing and low-level bombing attacks on enemy ground forces, tanks and other armoured vehicles, and installations. Attack aircraft are typically slower and less maneuverable than air-combat fighters but carry a large and varied load of weapons (automatic cannons, machine guns, rockets, guided missiles, and bombs) and have the ability to fly close to the ground.  During World War I, Germany and Britain strafed each other’s trenches from low-flying biplanes, but true attack aircraft did not emerge until early in World War II, when they acquired an important new mission, that of destroying tanks and other armoured vehicles. These new armoured monoplanes could endure heavy antiaircraft fire while attacking tanks and troop columns at very close range. The most important types were the Soviet Ilyushin Il-2 Stormovik and the U.S. Douglas A-20 Havoc, which were armed with 20-millimetre cannons and .30- or .50-inch machine guns. Two other American attack aircraft of the 1940s and ’50s were the Douglas B-26 Invader and the Douglas A-1 Skyraider. All of these types were piston-engined, propeller-driven aircraft.

After World War II, faster jet aircraft were developed for attack missions. Among the U.S. types were the Grumman A-6 Intruder, first flown in 1960; the U.S. Navy’s McDonnell Douglas A-4 Skyhawk, first flown in 1954; and the Ling-Temco-Vought A-7 Corsair, first flown in 1965. The Fairchild Republic A-10A Thunderbolt II, a two-seat, twin-engine aircraft first flown in 1972, became in the mid-1970s the principal close-support attack aircraft of the U.S. Air Force. Its primary armament is a nose-mounted, seven-barreled, 30-millimetre cannon that is an extremely effective “tank killer.” The Soviet Union’s evolving lines of jet-powered attack aircraft date back to the Sukhoi Su-7 (known in the West by the NATO-assigned name Fitter), a single-seat, single-engine aircraft that entered service in the late 1950s and was progressively improved after that time. Soviet development efforts culminated in the late 1970s and ’80s with the MiG-27 Flogger-D and the Sukhoi Su-25 Frogfoot. Late in the Cold War standoff, the Warsaw Pact and NATO alliances countered each other’s numerous armoured divisions in central Europe with the Soviet Su-25 and the U.S. A-10A respectively, which were designed to approach tank formations at treetop level before popping up to attack with guided missiles and rotary cannon.

Conventional fighters and tactical fighter-bombers have also been pressed into service as ground attack aircraft, a role aided by the use of sophisticated electronic targeting systems and precision-guided munitions. Attack helicopters loaded with machine guns, automatic cannon, and antitank rockets and missiles have also tended to assume the close-support functions of fixed-wing aircraft.