The Fairchild Republic A-10 Thunderbolt II, commonly referred to by the nicknames “Warthog” or “Hog”, was designed for close air support (CAS) of friendly ground troops, attacking armored vehicles and tanks, and providing quick-action support against enemy ground forces. The A-10 was designed for close air support (CAS) of friendly ground troops, attacking armored vehicles and tanks, and providing quick-action support against enemy ground forces. Although the A-10 can carry a considerable amount of munitions, its primary built-in weapon is the 30×173 mm GAU-8/A Avenger autocannon. One of the most powerful aircraft cannons ever flown, it fires large depleted uranium armor-piercing shells.
The GAU-8 is a hydraulically driven seven-barrel rotary cannon designed specifically for the anti-tank role with a high rate of fire. The cannon’s original design could be switched by the pilot to 2,100 or 4,200 rounds per minute; this was later changed to a fixed rate of 3,900 rounds per minute. The cannon takes about half a second to reach top speed, so 50 rounds are fired during the first second, 65 or 70 rounds per second thereafter. The gun is accurate enough to place 80 percent of its shots within a 40-foot (12.4 m) diameter circle from 4,000 feet (1,220 m) while in flight. The GAU-8 is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30-degree dive.
The fuselage of the A-10 Thunderbolt II is built around the cannon. The GAU-8/A is mounted slightly to the port side; the barrel in the firing location is on the starboard side at the 9 o’clock position so it is aligned with the aircraft’s centerline. The rotary cannon’s 5-foot, 11.5-inch (1.816 m) ammunition drum can hold up to 1,350 rounds of 30 mm ammunition, but generally holds 1,174 rounds. To protect the GAU-8/A rounds from enemy fire, armor plates of differing thicknesses between the aircraft skin and the drum are designed to detonate incoming shells. The front landing gear is offset to the aircraft’s right to allow placement of the 30 mm cannon with its firing barrel along the centerline of the aircraft.
The General Electric GAU-8/A Avenger is a 30 mm hydraulically driven seven-barrel Gatling-style autocannon designed specifically for the anti-tank role, the Avenger delivers very powerful rounds at a high rate of fire. The GAU-8/A ammunition feed is linkless, reducing weight and avoiding a great deal of potential for jamming. The feed system is double-ended, allowing the spent casings to be recycled back into the ammunition drum, instead of ejected from the aircraft, which would require considerable force to eliminate potential airframe damage. The feed system is based on that developed for later M61 installations, but uses more advanced design techniques and materials throughout, to save weight.