The A-10 Thunderbolt II is an American single-seat, twin-engine, straight-wing jet aircraft developed by Fairchild-Republic for the United States Air Force to provide close air support (CAS) of ground forces by attacking tanks, armored vehicles and other ground targets with a limited air interdiction capability. It is the first U.S. Air Force aircraft designed exclusively for close air support. The A-10's official name comes from the Republic P-47 Thunderbolt of World War II, a fighter that was particularly effective at close air support. The A-10 is more commonly known by its nickname "Warthog" or simply "Hog". As a secondary mission, it provides airborne forward air control, guiding other aircraft against ground targets. A-10s used primarily in this role are designated OA-10 Criticism that the U.S. Air Force did not take close air support seriously prompted a few service members to seek a specialized attack aircraft. In the Vietnam War, large numbers of ground-attack aircraft were shot down by small arms, surface-to-air missiles, and low-level anti-aircraft gunfire, prompting the development of an aircraft better able to survive such weapons. In addition, the UH-1 Iroquois and AH-1 Cobra helicopters of the day, which USAF commanders had said should handle close air support, were ill-suited for use against armor, carrying only anti-personnel machine guns and unguided rockets meant for soft targets. The F-4 Phantom II was pressed into close air support, but usually in emergencies, as its high cruising speed and fuel consumption hindered its ability to loiter. The lack of a gun on most F-4 variants, coupled with the relative ineffectiveness of the standard 20 mm round on M61 Vulcan-equipped F-4Es against hard targets, made strafing runs either impossible or ineffective.
The A-10 has superior maneuverability at low speeds and altitude, thanks to straight, wide wings with downturned "droop" wing tips. These also allow short takeoffs and landings, permitting operations from rugged, forward airfields near front lines. The aircraft can loiter for extended periods of time and operate under 1,000 feet (300 m) ceilings with 1.5-mile (2.4 km) visibility. It typically flies at a relatively slow speed of 300 knots (345 mph or 555 km/h), which makes it a much better candidate for the ground-attack role than fast fighter-bombers, which often have difficulty targeting small and slow-moving targets. Engine exhaust passes over the aircraft's horizontal stabilizer and between the twin tails, decreasing the A-10's infrared signature and lowering the likelihood that the aircraft can be targeted by heat-seeking missiles. The placement of the engines behind the wings partially shields them from anti-aircraft fire. The leading edge of the mainplane is honeycomb to provide strength with minimal weight compromise. Honeycomb panels of this type on the A-10 include the flap shrouds, elevators, rudders, and other sections of the fins. There are several reasons for the unusual location of the A-10's General Electric TF34-GE-100 turbofan engines. First, the A-10 was expected to fly from forward air bases, often with semi-prepared substandard runways that presented a high risk of foreign object damage to the engines. The height of the engines lowers the chance that sand or stones will enter the inlet. This also allows engines to remain running, allowing for shorter servicing and rearming turn-around times by ground crew. Servicing and rearming are further helped by having wings closer to the ground than would be possible if the engines were wing-mounted. The position also reduces the IR signature, which starts low anyway due to the engines' 6:1 bypass ratio. Because of their high position, the engines are angled upward nine degrees to bring the combined thrust line closer to the aerodynamic center of the aircraft. This avoids trimming measures to counteract a nose-down pitching moment if the engines were parallel to the fuselage. The heavy engines require strong supports, so their pylons are connected to the airframe by four boltsAlthough the A-10 can carry considerable disposable stores, its primary built-in weapon is the 30 mm GAU-8/A Avenger Gatling gun. One of the most powerful aircraft cannons ever flown, it fires large depleted uranium armor-piercing shells. In the original design, the pilot could switch between two rates of fire: 2,100 or 4,200 rounds per minute; this was changed to a fixed rate of 3,900 rounds per minute. The cannon takes about half a second to come up to speed, so 50 rounds are fired during the first second, 65 or 70 rounds per second thereafter. The gun is consistently accurate; it can place 80% of its shots within a 40-foot (12.4 m) circle from 4,000 feet (1,220 m) while in flight.[20] The GAU-8 is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30 degree diver.
The A-10 has superior maneuverability at low speeds and altitude, thanks to straight, wide wings with downturned "droop" wing tips. These also allow short takeoffs and landings, permitting operations from rugged, forward airfields near front lines. The aircraft can loiter for extended periods of time and operate under 1,000 feet (300 m) ceilings with 1.5-mile (2.4 km) visibility. It typically flies at a relatively slow speed of 300 knots (345 mph or 555 km/h), which makes it a much better candidate for the ground-attack role than fast fighter-bombers, which often have difficulty targeting small and slow-moving targets. Engine exhaust passes over the aircraft's horizontal stabilizer and between the twin tails, decreasing the A-10's infrared signature and lowering the likelihood that the aircraft can be targeted by heat-seeking missiles. The placement of the engines behind the wings partially shields them from anti-aircraft fire. The leading edge of the mainplane is honeycomb to provide strength with minimal weight compromise. Honeycomb panels of this type on the A-10 include the flap shrouds, elevators, rudders, and other sections of the fins. There are several reasons for the unusual location of the A-10's General Electric TF34-GE-100 turbofan engines. First, the A-10 was expected to fly from forward air bases, often with semi-prepared substandard runways that presented a high risk of foreign object damage to the engines. The height of the engines lowers the chance that sand or stones will enter the inlet. This also allows engines to remain running, allowing for shorter servicing and rearming turn-around times by ground crew. Servicing and rearming are further helped by having wings closer to the ground than would be possible if the engines were wing-mounted. The position also reduces the IR signature, which starts low anyway due to the engines' 6:1 bypass ratio. Because of their high position, the engines are angled upward nine degrees to bring the combined thrust line closer to the aerodynamic center of the aircraft. This avoids trimming measures to counteract a nose-down pitching moment if the engines were parallel to the fuselage. The heavy engines require strong supports, so their pylons are connected to the airframe by four boltsAlthough the A-10 can carry considerable disposable stores, its primary built-in weapon is the 30 mm GAU-8/A Avenger Gatling gun. One of the most powerful aircraft cannons ever flown, it fires large depleted uranium armor-piercing shells. In the original design, the pilot could switch between two rates of fire: 2,100 or 4,200 rounds per minute; this was changed to a fixed rate of 3,900 rounds per minute. The cannon takes about half a second to come up to speed, so 50 rounds are fired during the first second, 65 or 70 rounds per second thereafter. The gun is consistently accurate; it can place 80% of its shots within a 40-foot (12.4 m) circle from 4,000 feet (1,220 m) while in flight.[20] The GAU-8 is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30 degree diver.
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