Operating Systems

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The Gatling gun is perhaps the historically oldest operating system described here. Unlike blowback, recoil and gas operation, cycling energy is typically not derived from the fired cartridge but from external sources. Though fundamentally different from the other systems and never found in man-portable form, Gatling's current significance warrants inclusion here.

When first deployed around 1865 Gatling's guns employed hand cranks to control cycling and firing. In most modern applications cycling energy comes from external electric or hydraulic motors. The significant task of accelerating massive ammunition feed belts is also usually delegated to motors. Note that some models do derive partial operating energy from ammunition gases. The continuous rotary motion of the barrels and smooth movement of other elements helps attain high cyclic rates. These motions resemble those found in high-speed manufacturing systems.

Phalanx CIWS The modern Gatling gun is usually composed of 3 to 7 barrels in a circular array. In operation, the barrels and inner receiver rotate together. Independent bolts, one aligned and moving with each barrel, follow a helical cam track in the outer receiver. The cam track controls the feeding, locking, and extracting functions by moving each bolt fore and aft relative to its barrel. The timing of the system is fixed by the position of the bolt in track versus rotation. Each bolt typically contains its own striker or other firing device. (Cannon cartridges are usually electrically primed.)

Until about 1950 the Gatling gun was considered a 19th century anachronism. Then, demand for longer-range rapid-fire aircraft guns saw the revival of this concept in the form of the 20mm Vulcan automatic cannon. The Vulcan cannon, and its' copies and derivatives remain widely deployed in fighter aircraft throughout the world. Other special applications include use with the awesomely powerful 30mm round in the Fairchild A-10 "tank buster" ground attack aircraft, and the 20mm Phalanx Close In Weapons System (abbreviated CIWS and pronounced "see-wiz") used aboard U.S Navy ships as a last-ditch defense against sea-skimming missiles such as Exocet. The Gatling-derived Vulcan system was also scaled down for use in helicopters and fixed-wing gunships during the Vietnam era as the 7.62mm NATO-cartridged General Electric Minigun.

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