A rotary cannon, rotary autocannon, rotary gun or Gatling cannon, is any large-
caliber
In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel Gauge (firearms) , bore – regardless of how or where the bore is measured and whether the f ...
multiple-barreled automatic firearm
An automatic firearm is an auto-loading firearm that continuously chambers and fires rounds when the trigger mechanism is actuated. The action of an automatic firearm is capable of harvesting the excess energy released from a previous discharg ...
that uses a
Gatling-type rotating barrel assembly to deliver a sustained
saturational direct fire at much greater
rates of fire than single-barreled
autocannon
An autocannon, automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large-caliber ( or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bull ...
s of the same caliber. The loading, firing and ejection functions are performed simultaneously in different barrels as the whole assembly rotates, and the rotation also permits the barrels some time to cool. The rotating barrels on nearly all modern Gatling-type guns are powered by an external force such as an
electric motor, although internally powered
gas-operated versions have also been developed.
The cyclic multi-barrel design synchronizes the firing/reloading sequence. Each barrel fires a single
cartridge when it reaches a certain position in the rotation, after which the spent casing is ejected at a different position and then a new round is loaded at another position. During the cycle, the barrel has more time to dissipate some heat away to the surrounding air.
Due to the usually cumbersome size and weight of rotary cannon, they are typically mounted on
weapons platforms such as
vehicles,
aircraft, or
ships, where they are often used in
close-in weapon systems.
History
In 1852 a revolving barrel gun with a unique method of ignition was proposed by an Irish immigrant to America by the name of Delany.
The
Gatling gun
The Gatling gun is a rapid-firing multiple-barrel firearm invented in 1861 by Richard Jordan Gatling. It is an early machine gun and a forerunner of the modern electric motor-driven rotary cannon.
The Gatling gun's operation centered on a cyc ...
was another gun to use rotating barrels. It was designed by the American inventor
Dr. Richard J. Gatling in 1861 and patented in 1862.
Hand cranked and hopper fed, it could fire at a rate of 200 rounds per minute. The Gatling gun was a field weapon, first used in warfare during the
American Civil War and subsequently by European and Russian armies.
The design was steadily improved; by 1876 the Gatling gun had a theoretical rate of fire of 1,200 rounds per minute, although 400 rounds per minute was more readily achievable in combat. By 1893, the M1893 Gatling gun could fire 800 to 900 rounds per minute.
Ultimately the Gatling's weight and cumbersome artillery carriage hindered its ability to keep up with infantry forces over difficult ground and was superseded by lighter and more mobile machine guns such as the
Maxim gun. All models of Gatling guns were declared obsolete by the U.S. Army in 1911, after 45 years of service.
Development of modern Gatling-type guns
After the Gatling gun was replaced in service by newer recoil- or gas-operated non-rotating machine guns, the approach of using multiple rotating barrels fell into disuse for many decades. However, some examples were developed during the interwar years but only existed as prototypes, or rarely used. During
World War I,
Imperial Germany worked on the
Fokker-Leimberger
The Fokker-Leimberger was an externally powered, 12-barrel rifle-caliber rotary gun developed in Germany during the First World War. The action of the Fokker-Leimberger differed from that of a Gatling in that it employed a rotary split-breech des ...
, an externally powered 12-barrel Gatling gun that could fire more than 7,200 7.92×57mm rounds per minute.
After
World War II, the
U.S. Army Air Force
The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
determined that an automatic cannon of improved design with an extremely high rate of fire was required to achieve a sufficient number of large-caliber hits on fast-moving enemy jet
aircraft. Using experience gained from
20mm MG 151 and
30mm MK 108 cannon used by ''
Luftwaffe'' aircraft, a larger-caliber cannon shell for the new gun was deemed desirable, as it contained room for an explosive with more destructive force than the .30 and .50 caliber machine gun cartridges previously employed, and thus capable of destroying aircraft with only a few hits on target.
In June 1946, the General Electric Company was awarded a U.S. military defense contract to develop an aircraft gun with a high rate of fire which GE termed ''Project Vulcan''. While researching prior work, ordnance engineers recalled the experimental electrically driven Gatling weapons of the turn of the 20th century. In 1946, a Model 1903 Gatling gun borrowed from a museum was set up with an electric motor drive and test-fired by General Electric engineers. The 40-year-old design briefly managed a rate of fire of 5,000 rounds per minute.
In 1949 General Electric began testing the first model of its modified Gatling design, now called the ''Vulcan Gun''. The first prototype was designated the T45 (Model A). It fired ammunition at about 2,500 rounds per minute, from six barrels driven by an
electric motor. In 1950, GE delivered ten initial model A .60 cal. T45 guns for evaluation. Thirty-three model C T45 guns were delivered in 1952 in three calibers: .60 cal., 20mm, and 27mm, for additional testing. After extensive testing, the T171 20mm gun was selected for further development. In 1956, the T171 20mm gun was standardized by the U.S. Army and U.S. Air Force as the M61 20mm Vulcan aircraft gun.
One of the main reasons for the resurgence of the electrically or hydraulically powered multiple-barrel design is the weapon's tolerance for continuous high
rates of fire. For example, 1000 rounds per minute of continuous fire from a conventional single-barrel weapon ordinarily results in rapid barrel heating followed by stoppages caused by overheating. In contrast, a five-barreled machine gun firing 1000 rounds per minute fires only 200 rounds per barrel per minute, an acceptable rate of fire for continuous use. The only limiting factor is the rate at which loading and extraction can occur. In a single-barrel design, these tasks must alternate; a multiple-barrel design allows them to occur simultaneously, using different barrels at different points in the cycle. The design also solves the problem of defective ammunition, which can cause a normal machinegun to malfunction when a cartridge fails to load, fire, or eject from the weapon. As it is powered by an independent source, the gun simply ejects the defective round along with the rest of the cartridges while continuing to operate.
Models
M61 Vulcan and other designs
The ''
M61 Vulcan'' 20 mm autocannon is the best-known of a family of weapons designed by
General Electric and currently manufactured by
General Dynamics
General Dynamics Corporation (GD) is an American publicly traded, aerospace and defense corporation headquartered in Reston, Virginia. As of 2020, it was the fifth-largest defense contractor in the world by arms sales, and 5th largest in the Uni ...
. The M61 is a six-barreled 20mm rotary cannon that fires at up to 6,600 rounds per minute. Similar systems are available in calibers ranging from 5.56 mm to 30 mm (the prototype
T249 Vigilante
The T249 Vigilante was a prototype 37 mm self-propelled anti-aircraft gun (SPAAG) designed as a replacement for the Bofors 40 mm gun and M42 Duster in US Army service. The system consisted of a 37 mm T250 six-barrel Gatling gun mou ...
AA platform featured a 37 mm chambering).
Another multi-barrel design is the hydraulically driven
GAU-8 Avenger
The General Electric GAU-8/A Avenger 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 ...
30 mm autocannon, carried on the
A-10 Thunderbolt II (Warthog) attack aircraft, a heavily armored close air-support aircraft. It is a seven-barreled cannon designed for tank-killing and is currently the largest bore multi-barrel weapon active in the U.S. arsenal, and heaviest autocannon ever mounted into an aircraft, outweighing the WW II German ''Bordkanone'' BK 7,5 75mm aircraft-mount, tank-killing single barrel autocannon by some 630 kg (1,389 lb), with ammunition.
The
Gryazev-Shipunov GSh-6-23 and
GSh-6-30 are Russian gas-powered rotary cannon with maximum cyclic rates of 9,000 to 10,000 rounds per minute.
Self-driven examples
While electric motors were used to rotate the Vulcan barrels, a few examples of self-operated Gatling-derived weapons use the blow-forward, recoil or gas impulse from their ammunition. The Bangerter machine gun uses a blow-forward operation and is the most complex example. The Slostin machine gun uses a similar operation but with gas pistons on each barrels. The
GShG-7.62 machine gun
The ''Glagolev-Shipunov-Gryazev'' GShG-7.62 (russian: Глаголев-Шипунов-Грязев ГШГ-7,62) is a four-barreled rotary machine gun designed in the Soviet Union, similar to firearms such as the M134 Minigun. It is a hybrid weapon ...
and
GSh-6-23
The Gryazev-Shipunov GSh-6-23 (russian: Грязев-Шипунов ГШ-6-23) (GRAU designation: 9A-620 for GSh-6-23, 9A-768 for GSh-6-23M modernized variant) is a six-barreled 23 mm rotary cannon used by some modern Soviet/Russian military ...
, both use a more effective, simpler gas piston drive in the center of the barrel cluster.
Minigun
Technically not a "cannon", the Minigun is more correctly classified as a
rotary machine gun.
During the
Vietnam War, the 7.62 mm caliber M134
Minigun was originally created to arm rotary-wing aircraft, and could be fitted to various helicopters as either a crew-served or a remotely operated weapon. With a rate of fire from 2,000 to 6,000 rounds per minute from a 4,000-round linked
belt
Belt may refer to:
Apparel
* Belt (clothing), a leather or fabric band worn around the waist
* Championship belt, a type of trophy used primarily in combat sports
* Colored belts, such as a black belt or red belt, worn by martial arts practition ...
, the Minigun proved to be one of the most effective non-explosive projectile weapons ever built and is still used in helicopters today.
As the GAU-2B/A, the Minigun was also used on the U.S. Air Force
AC-47
The Douglas AC-47 Spooky (also nicknamed "Puff, the Magic Dragon") was the first in a series of fixed-wing gunships developed by the United States Air Force during the Vietnam War. It was designed to provide more firepower than light and medi ...
,
AC-119 and
Lockheed AC-130 gunships. The AC-47 was known during the Vietnam War as
"Puff the Magic Dragon" and was said to be "the only thing that scared the
VC". This weapon was also used on selected USAF helicopters. With sophisticated navigation and target identification tools, Miniguns can be used effectively even against concealed targets. The crew's ability to concentrate the Minigun's fire very tightly produces the appearance of the 'Red Tornado'
AC-119K Stinger Gunship Photo 1.
from the light of the tracer
Tracer may refer to:
Science
* Flow tracer, any fluid property used to track fluid motion
* Fluorescent tracer, a substance such as 2-NBDG containing a fluorophore that is used for tracking purposes
* Histochemical tracer, a substance used for tr ...
s, as the gun platform circles a target at night.
See also
* Revolver cannon
* Chain gun
* List of multiple-barrel firearms
Below is a list of multiple-barrel firearms of all forms from around the world.Small Arms Illustrated, 2010
Pistols
Rifles
Flare launchers
Less lethal
Automatic rifles
Submachine guns
Shotguns
Machine guns
Grenade launchers
S ...
References
External links
List of Military Gatling & Revolver cannon
* ttp://www.techeblog.com/index.php/tech-gadget/feature-cg-animation-shows-gatling-gun-cycle-of-operation CGI animated GAU-17/A
Fokker Leimberger
Fokker Leimberger
{{Modern Gatling Guns
Autocannon
Multi-barrel machine guns