From Wikipedia, the free encyclopedia
|
GAU-12/U Equalizer |
| Type |
Rotary cannon |
| Place of origin |
 United States |
|
Production history |
| Designer |
General
Dynamics |
|
Specifications |
| Weight |
270 lb (122 kg) |
| Length |
83.2 in (2.11 m) |
| Width |
10 in (256 mm) |
| Height |
11.5 in (292 mm) |
|
| Caliber |
25 mm (0.98 in) |
| Action |
Hydraulic, Electric, Pneumatic |
| Rate of fire |
3600 - 4200 rounds per minute |
| Muzzle velocity |
(HEI) 3400 ft/s (1040 m/s); (API) 3280 ft/s (1000 m/s). |
| Feed system |
Linked or linkless |
| Sights |
Lead Computing Optical Sight System (LCOSS) |
The General Dynamics 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, Italy and Spain, which
mount the weapon in their fighter jets such as the AV-8B Harrier
II, airborne gunships
such as the Lockheed AC-130, and land-based
fighting vehicles.
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
driven 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 United States 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 GR7 and
GR9s. 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 GR7/9s are without gun armament.
The Equalizer is also used in the AC-130U Spectre 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.
GAU-22/A
The GAU-22/A is the latest application of the
GAU-12/U, which is a four barrel version designed for use on the F-35 Lightning
II.[1] 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 four barrel system, rather than the five
barrels on the standard GAU-12/U. The four barrel version is
purported to reduce weight and improve accuracy. This system is
currently undergoing intensive testing and qualification. The
weapon's current contractor is General Dynamics Armament and Technical
Products.
Specifications
(GAU-12)
- 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) 73,400 ft·lbf (99,500
joules); (API) 79,300 ft·lbf (107,500 joules)
Media
Test firing of GAU-22 gun
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