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38-444: The five-barrel Equalizer cannon was developed in the late 1970s, based on the mechanism of the 30mm GAU-8/A Avenger cannon, but firing a new NATO series of 25 mm ammunition. The GAU-12/U cannon is operated by an 11 kW (15 hp) electric motor , or 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. For use in

76-418: A Close-In Weapon System , as the gun was not automatic nor did it use radar tracking. Instead the gun was manually aimed using a digital gun sight and fire control. Sea Vulcan consisted of a 540-round helical drum magazine, a one-piece aluminum turret that can be opened with just a screwdriver, and the main gun. One unique advantage of the system was that it was capable of operating independently of ship's power;

114-416: A constant out-flow, and a varied in-flow (varied by the actuator and valve). A pressure transmitter will monitor the pressure in the vessel and transmit a signal from 20–100 kPa. 20 kPa means there is no pressure, 100 kPa means there is full range pressure (can be varied by the transmitters calibration points). As the pressure rises in the vessel, the output of the transmitter rises, this increase in pressure

152-465: A given weight. The projectiles incorporate a plastic driving band to improve barrel life. The cartridges measure 11.4 inches (290 mm) in length and weigh 1.53 pounds (0.69 kg) or more. The Avenger's rate of fire was originally selectable, 2,100 rounds per minute (rpm) in the low setting, or 4,200 rpm in the high setting. This rate was later changed to a fixed rate of 3,900 rpm. At this speed it would take 18 seconds of sustained fire to empty

190-581: A projectile weight of about 13.3 oz (378 grams or 5,833 grains). The PGU-14/B's projectile incorporates a lightweight aluminum body, cast around a smaller caliber depleted uranium penetrating core. In 1979, the Avenger was tested against M47 Patton tanks and caused "severe damage". An innovation in the design of the GAU-8/A ammunition is the use of aluminum alloy cases in place of the traditional steel or brass. This alone adds 30% to ammunition capacity for

228-425: A single burst with no damage or ill effects to the weapons system itself. However, this constant rate of fire would shorten the barrel life considerably and require added barrel inspections and result in shorter intervals between replacement. Each barrel is a very simple non-automatic design having its own breech and bolt . Like the original Gatling gun , the entire firing cycle is actuated by cams and powered by

266-404: Is 1,013 m/s, almost the same as the substantially lighter M61 Vulcan's 20 mm round, giving the gun a muzzle energy of just over 200 kilojoules . The standard ammunition mixture for anti-armor use is a five-to-one mix of PGU-14/B Armor Piercing Incendiary, with a projectile weight of about 14.0 oz (395 grams or 6,096 grains) and PGU-13/B High Explosive Incendiary (HEI) rounds, with

304-664: Is a 30 mm hydraulically driven seven-barrel Gatling-style autocannon that is primarily mounted in the United States Air Force 's Fairchild Republic A-10 Thunderbolt II . Designed to destroy a wide variety of ground targets, the Avenger delivers 30mm rounds at a high rate of fire . The GAU-8/A is also used in the Dutch Goalkeeper CIWS ship weapon system, which provides defense against short-range threats such as highly maneuverable missiles, aircraft, and fast-maneuvering surface vessels. The GAU-8/A

342-639: 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 Equalizer was also used as the basis for the Sea Vulcan 25 , a turret mounted gun for naval ship self-defense, although not as

380-553: The AC-130 gunship, the fire rate is limited to 1,800 rounds per minute in order to conserve ammunition and reduce barrel wear. The GAU-22/A is a four-barrel version of the GAU-12/U designed for use on the F-35 Lightning II . The GAU-22/A's major difference is the use of four barrels, rather than the GAU-12/U's five barrels. The GAU-22/A is lighter and has a reduced rate of fire of 3,300 rounds per minute, but maintains

418-463: The magazine , weighs 900 lb (410 kg) empty and 1,230 lb (560 kg) loaded. The detachable pods are located and shaped to be interchangeable with the usual ventral strakes or fences under the Harrier, both serving to help trap a cushion of high-pressure air under the aircraft to add lift while in hover mode. The strakes can easily be removed and the pods attached in their place, serving

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456-470: The A-10 carries the full-up Avenger system. Pneumatic actuator A pneumatic control valve actuator converts energy (typically in the form of compressed air ) into mechanical motion. The motion can be rotary or linear , depending on the type of actuator. A pneumatic actuator mainly consists of a piston or a diaphragm which develops the motive power. It keeps the air in the upper portion of

494-454: The A-10 is rated at "5 mil , 80 percent", meaning that 80 percent of rounds fired will hit within a cone with an angle of five milliradians ; this equates to a 40-foot (12-meter) diameter circle at the weapon's design range of 4,000 feet (1,200 m). By comparison, the M61 has an 8-milliradian dispersion. Because the gun's recoil forces could push the entire plane off target during firing,

532-774: The A-10A to the F-16A/B Block 10, and during Desert Storm their aircraft were equipped with the GPU-5/A Pave Claw pod housing the 30mm GAU-13/A, which was a four-barrel variant of the seven-barrel GAU-8 Avenger used by the A-10. These aircraft were redesignated F/A-16 and were the only F-16s equipped with this type of weapon. However, the F-16s suffered from poor accuracy (due to the less rigid pylon mounting and stronger vibrations when firing), lack of CCIP software, and faster flight speeds giving pilots less time to aim. The gun

570-499: The GAU-8/A has a muzzle velocity that is comparable to that of the M61 Vulcan , it uses heavier ammunition and has superior ballistics. The time of flight of its projectile to 4,000 feet (1,200 m) is 30 percent less than that of an M61 round; the GAU-8/A projectile decelerates much less after leaving the barrel, and it drops a negligible amount, about 10 feet (3.0 m) over the distance. The GAU-8/A precision when installed in

608-415: The GAU-8/A is 10,000 pounds-force (45 kN), which is slightly more than the output of each of the A-10's two TF34 engines of 9,065 lbf (40.3 kN). While this recoil force is significant, in practice a cannon-fire burst slows the aircraft by only a few miles per hour in level flight. Some of the GAU-8/A technology has been transferred into the smaller 25 mm GAU-12/U Equalizer , which

646-485: The aircraft's center of gravity than ejecting them. The feed system is based on that developed for later M61 installations, but uses more advanced design techniques and materials throughout, to save weight. The GAU-8/A is extremely accurate and can fire up to 3,900 rounds per minute without complications. The 30-mm shell has twice the range, half the time to target, and three times the mass of projectiles fired by guns mounted in comparable close air support aircraft. While

684-518: The airplane's tail whenever the gun is removed for inspection in order to prevent the aircraft from tipping rearwards. The gun is mounted slightly to the port side with the active firing cannon barrel on the starboard side at the 9 o'clock position and on the aircraft's center line. The front landing gear is positioned to the starboard side. The gun is loaded using Syn-Tech's linked tube carrier GFU-8/E 30 mm Ammunition Loading Assembly cart. The A-10 with its GAU-8/A gun entered service in 1977. It

722-458: The cylinder, allowing air pressure to force the diaphragm or piston to move the valve stem or rotate the valve control element. Valves require little pressure to operate and usually double or triple the input force. The larger the size of the piston, the larger the output pressure can be. Having a larger piston can also be good if the air supply is low, allowing the same forces with less input. These pressures are large enough to crush objects in

760-481: The firing of the gun. When the GAU-8 is being fired, the smoke from the gun can make the engines stop, and this did occur during initial flight testing. Gun exhaust is essentially oxygen-free, and is capable of causing flameouts of gas turbines . The A-10 engines now have a self-sustaining combustion section. When the gun is fired, the igniters come on to reduce the possibility of a flameout. The average recoil force of

798-480: The front landing gear, which is mounted slightly off-center on the starboard side of the nose. The GAU-8/A utilizes recoil adapters. They are the interface between the gun housing and the gun mount. By absorbing (in compression) the recoil forces, they spread the time of the recoil impulse and counter recoil energy transmitted to the supporting structure when the gun is fired. The A-10 engines were initially susceptible to flameout when subjected to gases generated in

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836-433: The fuselage underside, 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 (unlike previous Harriers which used dual cannons, with each pod containing a 30mm ADEN gun and its own ammunition supply). The complete installation, which includes a double-ended feed system that returns empty cartridges to

874-582: The gun and ammunition magazine were powered by a 3,000 psi (21 MPa) pneumatic drive and the turret motor by twin lead–acid batteries . Intended as a higher-firepower alternative to conventional deck-mounted machine guns and cannon, the weapon employs the Navy's Mk 24 target designator and laser range finder for enhanced accuracy. The gun was developed in the mid-1980s as a cost-effective protection for ships smaller than frigate or corvette or patrol boats, but did not enter this service. The GAU-12

912-451: The magazine. In practice, the cannon is limited to one and two-second bursts to avoid overheating and conserve ammunition; barrel life is also a factor, since the USAF has specified a minimum life of at least 20,000 rounds for each set of barrels. There is no technical limitation on the duration the gun may be continuously fired, and a pilot could potentially expend the entire ammunition load in

950-421: The muzzle to the rearmost point of the ammunition system, and the ammunition drum alone is 34.5 inches (88 cm) in diameter and 71.5 inches (1.82 m) long. Power for operating the gun is provided by twin hydraulic motors pressurized from two independent hydraulic systems. The magazine can hold 1,174 rounds, although 1,150 is the typical load-out. Muzzle velocity when firing armor-piercing incendiary rounds

988-461: The pipe. On 100 kPa input, you could lift a small car (upwards of 1,000 lbs) easily, and this is only a basic, small pneumatic valve. However, the resulting forces required of the stem would be too great and cause the valve stem to fail. This pressure is transferred to the valve stem, which is connected to either the valve plug (see plug valve ), butterfly valve etc. Larger forces are required in high pressure or high flow pipelines to allow

1026-611: The presence of a clockworking inertia-driven mechanical fuze in the mid-body, protects the round from shocks, misfires and cookoffs, making it safer to handle and fire. 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 detachable pods mounted on

1064-401: The rotation of the barrels. The seven-barrel carriage assembly itself is driven by the aircraft's dual hydraulic system. 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 returned to the ammunition drum. Additionally, returning empty cases to the drum has less effect on

1102-453: The same function while adding useful firepower. RAF and Fleet Air Arm Harriers did not adopt 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 were without gun armament until retirement. The Equalizer

1140-549: The same, high accuracy of 5 milliradians , 80% circle of the GAU-12 and A-10's GAU-8. The weapon is produced by General Dynamics Ordnance and Tactical Systems. The Nammo 25 mm PGU-47/U APEX (Armor Piercing with Explosive) projectile has been developed for the GAU-22/A. It features a tungsten carbide penetrator in the tip and an explosive fragmentation body, to be multi-purpose against both hardened and soft targets. Also,

1178-402: The valve to overcome these forces, and allow it to move the valves moving parts to control the material flowing inside. The valve's input is the "control signal." This can come from a variety of measuring devices, and each different pressure is a different set point for a valve. A typical standard signal is 20–100 kPa. For example, a valve could be controlling the pressure in a vessel that has

GAU-12 Equalizer - Misplaced Pages Continue

1216-483: The weapon is mounted laterally off-center, slightly to the port side of the fuselage centerline, with the active firing barrel lying 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. This configuration also leaves space for

1254-462: The weapon, although it was not available during the initial competition; the M61 Vulcan was used as a temporary replacement. Once completed, the entire GAU-8 assembly (correctly referred to as the A/A 49E-6 Gun System) represents about 16% of the A-10 aircraft's unladen weight. Because the gun plays a significant role in maintaining the A-10's balance and center of gravity, a jack must be installed beneath

1292-640: Was designed by General Electric and has been produced by General Dynamics since 1977. The GAU-8 was created as a parallel program with the A-X (or Attack Experimental) competition that produced the A-10. The specification for the cannon was laid out in 1970, with General Electric and Philco-Ford offering competing designs. Both of the A-X prototypes, the YA-10 and the Northrop YA-9 , were designed to incorporate

1330-662: Was developed for the AV-8B Harrier II aircraft. The GAU-12 is about the same size as the 20 mm M61 . GE has also developed the GAU-13/A , a four-barreled weapon using GAU-8/A components, which has been tested in podded form as the GPU-5/A . The Avenger also forms the basis for the Dutch-developed Goalkeeper CIWS naval air-defense gun. No current or contemplated aircraft other than

1368-463: Was found to be ineffective against point targets, and less effective than cluster munitions for area targets, leading the Air Force to quickly abandon the plan. The GAU-8 itself weighs 620 pounds (280 kg), but the complete weapon, with feed system and drum, weighs 4,029 pounds (1,828 kg) with a maximum ammunition load. It measures 19 ft 5 + 1 ⁄ 2  in (5.931 m) from

1406-537: Was produced by General Electric , though General Dynamics Armament and Technical Products has been responsible for production and support since 1997 when the division was sold by Lockheed Martin to General Dynamics . In November 1988, the US Air Force sought to pursue the idea of a dedicated CAS F-16 using the GAU-8 Avenger cannon from the A-10. The 174th Tactical Fighter Wing was transitioned off of

1444-752: Was utilized as the principal armament for the Rutan ARES . The four-barrel GAU-22 is carried internally by the F-35A (the CTOL version of the F-35) on the port side of the fuselage, with 181 PGU-47/U APEX rounds. In contrast, the F-35B STOVL and C CATOBAR aircraft mount the GAU-22 in a stealthy external gun pod under the fuselage, together with 220 rounds. GAU-8 The General Electric GAU-8/A Avenger

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