Wanna know what’s behind the trademark BRTTTTT noise of the A-10 Warthog’s GAU-8/A Avenger Gatling Gun? Then, watch this.
Dubbed Warthog, Hog or just Hawg, the A-10 Thunderbolt II is, basically, an airplane built around the GAU-8 Avenger 30-mm hydraulically driven seven-barrel Gatling-type cannon. The Avenger cannon is the Hog primary weapon and is able to fire 3,900 bullets per minute.
“It’s a highly-accurate point-and-shoot weapon that grants our pilots superior firepower and flexibility in a close-combat ground fight,” a Warthog pilot once told us. The GAU-8 is rated at “5 mil, 80 percent”, meaning that 80% of rounds will hit within a 5-mil circle with mils being milliradiants (at 1,000 feet five mils would be 5 m hence 80% of rounds would hit within a 5-m circle and that’s a 70 rounds a second).
Everything in the A-10 is designed to “make room” to the gun, including the nose landing gear, offset to the right of the aircraft so that the firing barrel lines up along the center of the airframe. More in detail, as the gun’s recoil forces could push the entire plane off target during strafes, the gun itself is mounted laterally off-center, slightly to the port side of the fuselage centerline, with the actively “firing” barrel in the nine o’clock position (when viewed from the front of the aircraft), so that the firing barrel lies directly on the aircraft’s centerline. The firing barrel also lies just below the aircraft’s center of gravity, being bore-sighted along a line 2 degrees below the aircraft’s line of flight. This arrangement accurately centers the recoil forces, preventing changes in aircraft pitch or yaw when fired.
Each of its seven barrels has an internal riffling groove which passes through the whole length of the barrel so that a spin on each round can be induced. The 1,150 30-mm rounds of bullets stored in the drum weigh about 4,000 pounds: this means that the weight of the rounds and their shells has to be taken in consideration to position of the center of gravity of the aircraft. Without the rounds, you would actually have to put ballast in the nose on an empty gun to balance the airplane!
Other design features of the Warthog support the operation of the Avenger. For instance, as explained by Major Cody “ShIV” Wilton, the commander of the A-10 Demo Team, in a pretty epic walkaround video we have published last year, the slat on each wing, that are not slats in the traditional airplane sense as they do not generate lift nor help the pilot land any slower it, but they smooth the airflow off the wing in the engine and prevent stalls when the aircraft flies at high AOA (Angle Of Attack), also helps diverting the gun gas underneath the wing so it doesn’t suffocate the engine (as the gun gas does not have oxygen) when the aircraft uses the gun. There’s also a wind fence that, when the gun is shooting, diverts the gas down the fuselage.
The stunning video below, produced by the 3D Mil-Tech YouTube channel, shows with unprecedented details, how the GAU-8 Avenger works: it gives an idea of the seven-barrel carriage assembly including the double-ended feed system which allows the spent casings to be returned to the ammunition drum.
What a fine piece of machinery!