GAU-12 Equalizer

Infobox Weapon
name=GAU-12/U Equalizer
origin=flagcountry|United States
type=Rotary cannon
is_ranged=Y
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designer=General Electric
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weight=270 lb (122 kg)
length=83.2 in (2.11 m)
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width=10 in (256 mm)
height=11.5 in (292.2 mm)
crew=
cartridge=
caliber=25 mm (0.98 in)
action=Hydraulic, Electric, Pneumatic
rate=3600 - 4200 rounds per minute
velocity=(HEI) 3400 ft/s (1040 m/s); (API) 3280 ft/s (1000 m/s).
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feed=Linked or linkless
sights=Lead Computing Optical Sight System (LCOSS)
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The General Electric GAU-12/U Equalizer is a five-barrel 25 mm Gatling gun-style rotary cannon. The GAU-12/U is used by the United States, the UK, and several other NATO nations, which mount the weapon in their fighter jets (e.g., the Harrier), airborne gunships (e.g., the AC-130), and land-based fighting vehicles. The GAU-22/A is a 4-barrel version designed for use on the F-35 Lightning II.

Development

The five-barrel 'Equalizer' cannon was developed in the late 1970s, based on the mechanism of the GAU-8/A Avenger cannon, but firing a new NATO series of 25 mm ammunition. The GAU-12/U cannon is operated by a 15 hp (11 kW) electric motor, in external mounts supplied by a bleed air-drive pneumatic system. Its rate of fire is normally 3,600 rounds per minute, with a maximum of 4,200 rounds per minute.

The Equalizer normally uses PGU-20/U armor-piercing incendiary (API) or PGU-22 or PGU-25 high-explosive incendiary (HEI) ammunition. With a harder-hitting projectile and comparable muzzle velocity, it is more lethal than the older M61 Vulcan, and more effective than the older 30 mm ADEN cannon it replaces.

Current uses

The current principal application for the Equalizer is the AV-8 Harrier IIs of the U.S. Marine Corps, Italian Navy and Spanish Navy. The Harrier II carries the Equalizer system in a pair of pods mounted on the fuselage sides, with the cannon in the port pod and 300 rounds of ammunition in the starboard pod, fed through a bridge at the aft ends of the pods that also contains the drive system for the gun. The complete installation, which includes a double-ended feed system that returns empty cartridges to the magazine, weighs 900 lb (410 kg) empty and 1,230 lb (560 kg) loaded.

RAF and Fleet Air Arm Harriers have not adopted the Equalizer for their Harrier GR Mk7 and 9s. The British had originally planned a pair of ADEN 25 guns (using the same ammunition as the GAU-12/U, but based on the 30 mm ADEN cannon). That gun was canceled in 1999 after protracted development problems, and British Harrier GR Mk7/9s are without gun armament.Fact|date=June 2007

The Equalizer is also used in the AC-130U 'Spooky' gunship (where one cannon is mounted on the port side) and the U.S. Marine Corps LAV AD air-defense vehicle. Other applications have been planned for the GAU-12/U, including a mounting for the AH-1 Cobra attack helicopter.

The latest application of the GAU-12/U is the GAU-22/A [Maher, Dave. "National Defense Industrial Association". 30 March 2006 [http://www.dtic.mil/ndia/2006garm/thursday/maher.pdf 25mm Gun Systems for the F-35 Joint Strike Fighter] . Access Date: 13 August 2007] for the F-35 Lightning II. In the CTOL version of the aircraft it will carry the gun internally, while on the STOVL and CV versions an external podded gun will be available. The major difference between the GAU-12/U and the GAU-22/A is the use of a 4-barrel system, rather than the 5 barrels on the standard GAU-12/U. The 4-barrel version is purported to reduce weight and improve accuracy. This system is currently undergoing testing and qualification. The weapon's current contractor is General Dynamics Armament Systems.

pecifications

* Type: Five-barreled rotary cannon
* Caliber: 25 mm (0.98 in)
* Operation: electric
* Length: 83.2 in (2.11 m)
* Weight (complete): 270 lb (122 kg)
* Rate of fire: 3,600 - 4,200 rounds per minute
* Muzzle velocity: (HEI) 3,400 ft/s (1,040 m/s); (API) 3,280 ft/s (1,000 m/s)
* Projectile weight: (HEI) 6.5 oz (184 g); (API) 7.6 oz (215 g)
* Muzzle energy: (HEI) 73,394 ft·lbf (99,507 Joules); (API) 79,289 ft·lbf (107,500 Joules)

References

Media

External links

* [http://www.gdatp.com/products/Gun_Systems/GAU-12U/GAU-12U.htm GAU-12/U page] and [http://www.gdatp.com/products/Gun_Systems/JSF/JSF.htm F-35 JSF gun system page on General Dynamics Armament and Technical Products (manufacturer) site]
* [http://www.fas.org/man/dod-101/sys/ac/equip/gau-12.htm FAS.org: GAU-12 Equalizer]
* [http://www.globalsecurity.org/military/systems/aircraft/systems/gau-12.htm Globalsecurity.com's article on the GAU-12]