Helicopter armament systems developed by the United States military since the early 1960s include offensive and defensive weapons and gear of various types, including machine guns, grenade launchers, autocannon, and rockets.

Introduction

The United States Army began to experiment with air mobile tactics during the Korean War, and by 1962, was developing armed helicopters for attack and defense. That year saw the deployment of the UTTHCO (Utility Tactical Transport Helicopter Company) to help the South Vietnamese Army and to test new air mobile theory. Weapons used by UTTHCO were often crude and made from parts and weapons readily available in the field.Mutza, 2004. p. 23.

By 1965, the United States had deployed an Air Mobile unit, the 17th Cavalry, which began to use more standardized armament. During the Vietnam War, the US Army, US Marine Corps, and US Air Force developed and used armament systems for a variety of helicopters.

With the arrival of dedicated gunship helicopters such as the AH-1 Cobra, introduced in 1967, and later the AH-64 Apache, armament subsystems for non-specific types would begin to drop off, although defensive armament packages remained popular.

Designated systems Systems designated by the US Army include:

Nomenclature Aircraft Weapon(s)Armament Subsystem, Helicopter, Caliber .30 Machine Gun, Twin, M1Bell OH-13 Sioux and Hiller OH-23 RavenM37C machine gunArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Twin, M2 OH-13 Sioux and OH-23 RavenM60C machine gunHelicopter Armament Subsystem, 2.75-Inch Rocket Launcher, M3UH-1B/C/M IroquoisMk 4/Mk 40 Folding-Fin Aerial Rocket (FFAR)Helicopter Armament Subsystem, 2.75-Inch Rocket Launcher, M4CH-34 Choctaw Mk 40 FFARArmament Subsystem, Helicopter, 40-MM Grenade Launcher, M5UH-1B/C/M IroquoisM75 grenade launcherArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Quad, M6 UH-1B/C Iroquois M60C machine gunArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Twin, M7OH-6 Cayuse M60C machine gunArmament Subsystem, Helicopter, 40-MM Grenade Launcher, M8OH-6 CayuseM129 grenade launcherArmament Subsystem, Helicopter, 7.62-MM Machine Gun - 2.75-Inch Rocket Launcher, M16UH-1B/C Iroquois M60C machine gun and Mk 40 FFARArmament Subsystem, Helicopter, 2.75-Inch Rocket Launcher, M17UH-1B/C IroquoisMk 40 FFARArmament Subsystem, Helicopter, 7.62-MM Machine Gun - 2.75-Inch Rocket Launcher, Twin, High Rate, M21UH-1B/C/M IroquoisM134 machine gun and Mk 40 FFARGuided Missile Launcher, Helicopter Armament Subsystem, M22UH-1B/C IroquoisSS.11 (as AGM-22) missileArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Door Mounted, Lightweight, M23UH-1D/H IroquoisM60D machine gunArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Door Mounted, Lightweight, M24CH-47 Chinook M60D machine gunGuided Missile Launcher, Helicopter Armament Subsystem, M26UH-1B/C IroquoisBGM-71 TOW missileArmament Subsystem, Helicopter, 7.62-MM Machine Gun, High Rate, M27OH-6 CayuseM134 machine gunArmament Subsystem, Helicopter, 7.62-MM Machine Gun - 40-MM Grenade Launcher, M28AH-1G/Q/R/S CobraM134 machine gun and M129 grenade launcherArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Door Mounted, Lightweight, M29UH-1B/C IroquoisM60D machine gunArmament Subsystem, Helicopter, 30-MM Cannon, M30UH-1B/C IroquoisXM140 cannonArmament Subsystem, Helicopter, 20-MM Cannon, M31UH-1B/C IroquoisM24A1 cannonArmament Subsystem, Helicopter, M32ACH-47A ChinookM60D machine gun or M2HB machine gun. Armament Subsystem, Helicopter, M33ACH-47A Chinook M60D machine gun or M2HB machine gunArmament Subsystem, Helicopter, 20-MM Cannon, M34ACH-47A ChinookM24A1 cannonArmament Subsystem, Helicopter, 20-MM Cannon, High Rate, M35AH-1G CobraM195 cannonArmament Subsystem, Helicopter, 7.62-MM Machine Gun, Ramp Mounted, Lightweight, M41CH-47 ChinookM60D machine gunArmament Subsystem, Helicopter, 7.62-MM Machine Gun - 2.75-Inch Rocket Launcher - 40-MM Grenade Launcher, Twin, High Rate, M50UH-1B/C/M IroquoisM134 machine gun, M75 grenade launcher, and Mk 40 FFARArmament Subsystem, Helicopter, 40-MM Grenade Launcher, M51AH-56 CheyenneM129 grenade launcherArmament Subsystem, Helicopter, 30-MM Cannon, M52AH-56 CheyenneXM140 cannonArmament Subsystem, Helicopter, 7.62-MM Machine Gun, High Rate, M53AH-56 CheyenneM196 machine gunArmament Subsystem, Helicopter, Door Mounted, M59UH-1D/H IroquoisM213 machine gun or XM175 Grenade LauncherArmament Subsystem, Helicopter, 7.62-MM Machine Gun, M64AH-1G CobraM134 machine gunGuided Missile Launcher, Helicopter Armament Subsystem, M65AH-1E/F/P/Q/R/S CobraBGM-71 TOW missileArmament Subsystem, Helicopter, Door Mounted, M93UH-1F/P/N IroquoisM134 machine gunArmament Subsystem, Helicopter, Door Mounted, M94UH-1F/P/N IroquoisM134 machine gun or M129 grenade launcherArmament Subsystem, Helicopter, 20-MM Cannon, M97AH-1E/F/P Cobra M197 electric cannonArmament Subsystem, Helicopter, M120AH-1 CobraM134, M60C machine gun or XM140 cannon, XM188, M197 electric cannonArmament Subsystem, Helicopter, M139AH-64 ApacheM230 chain gun and Mk 66 Wrap-Around Fin Aerial Rocket (WAFAR)

Transport and utility helicopters

UH-1 Iroquois

XM3, XM3E1/M3, and TLSS The M3, sometimes referred to as "Aerial Rocket Artillery" (ARA), consisted of two 2.75" 24-Tube rocket launchers, one on either side of the aircraft, along with a Mk 8 sight. The launchers fired in pairs, one from each side to prevent the aircraft from becoming off balance. M3 systems were attached to the helicopter using Bell designed stores racks.US Army TACOM-RI. 5 October 2005 U.S. Army Helicopter Weapon Systems (Page 1 of 2) . Access Date: 7 May 2007United States, 1969. p. B-1 The only difference between the XM3 and XM3E1 was that the launch tubes on the E1 were 4" longer. The XM3E1 was standardized as the M3.

A subvariant of the M3 system was developed in 1964 by the US Army Limited War Laboratory that allowed equipped helicopters to produce a protective smoke screen. Called the "Troop Landing Smoke Screen" (TLSS), the system used modified M3 launch racks to dispense M8 smoke grenades.Squieler, 1966. p. 1 This system was later tested using M6 and M7 riot control grenades.United States, 1965. p. 2

XM5/M5 The XM5/M5 system consists of a nose turret for a single 40mm M75 grenade launcher. The mount was fully flexible and controlled by the pilot via a hand-controlled sight electronically linked to the turret. The system either provided 150 or 302 rounds of ammunition.Mutza, 2004. p. 25 This system was also part of the armament kit for the ACH-47A.Drendel, 1974. p. 8

M6 Series

The M6 system was one of the first systems to make use of the XM156/M156 universal mount, providing two M60C 7.62×51mm machine guns on either side of the helicopter.Mutza, 2004. p. 22 This system would later be expanded upon, but initially gave the UH-1 increased firepower and an improved offensive system over the skid mounts originally used.

The various development stages of the M6 system mainly had to do with the "station" to which the M156 mount was attached. The position of the XM6 is not stated, but the XM6E2 was fitted to "station 69" (likely forward of the main cabin) and the XM6E3 was fitted to "station 136." Since the XM6E3 was standardized as the M6, "station 136" is assumed to be the aft of main cabin position that would become standard for M156 based systems.

Some M6 systems were coupled the four guns with four MA-2/A 2.75" 2-Tube rocket launchers on each side of the aircraft, giving an even greater punch. This arrangement was later supplanted by the XM16/M16 system.

XM9 A variant of the XM6/M6 system, the XM9 substitutes the four M60C 7.62×51mm machine guns with two M75 grenade launchers, one on either side of the aircraft.

XM11, XM22/M22, and the Maxwell System

Both of these armament systems were designed to allow the UH-1 to fire the AGM-22 missile. Sources claim that the XM11 provided an XM70 sight and support racks for 6 missiles, three on each side of the aircraft. However, US Army FM 1-40 says that the XM11 designation was unassigned.

The M22 was an improvement providing a more specific sight, the XM58, and using the XM156 universal mount. The M22 also provided for a total of 6 missiles, three on each side of the aircraft. The XM11 is associated with the standard SS.11 missiles (AGM-22A), while the XM22/M22 system was designed around the US upgraded AGM-22B missiles.Mutza, 2004. p. 41

The Maxwell System was a hybrid system designed by Warrant Officer Robert Maxwell as a field modification. Maxwell's unit had been sent both the M3 and XM11 systems, and he noticed that often aircraft with the M3 system returned after only firing half or less than half of their total rocket load. By removing one or two banks of rockets (and reducing the total carried to 12 or 18 total rockets versus 24) and adding a single launching mount for an AGM-22 missile he effectively gave the aircraft both suppression and point attack capabilities. The general lack of point targets in South East Asia meant that SS.11/AGM-22 missile saw very limited use in general.

XM16/M16

The XM16/M16 system mated the previous M6 with either two M157 or two M158 2.75" 7-Tube rocket launchers utilizing the M156 Universal Mount. Sighting was accomplished by using the M60 series reflex sight. The combined weight and aircraft limitations meant that only seven-tube launchers could be used.Mutza, 2004. p. 24

XM17 The XM17 utilized "Kellet pylons" to mount two XM159 2.75" rocket launchers, one on each side of the aircraft.

XM21/M21 A further variation on what had essentially become a basic system, the XM21/M21 subsystem replaced the XM16/M16's four M60Cs with two M134 7.62×51mm Miniguns.

XM23/M23 The M23 system provides a pintle mount at both main cabin doors for an M60D 7.62×51mm machine gun, with the weapon feeding from either a standard ammunition box or a larger purpose built box connected to the mount.Mesko, 1984. p. 53 The M23 is specifically designed for long fuselage UH-1s (UH-1D/H/N).

XM26

With the development of the BGM-71 TOW missile Hughes had been given the contract to develop a launching system for the UH-1. By 1968 development had shifted over to development of a system for the AH-56 helicopter which was eventually canceled. The XM26 provided two 3-Tube launchers on either side of the aircraft, as well as the necessary sighting equipment. While the XM26 was more of a test platform, the two prototypes were deployed operationally as an emergency measure in South Vietnam to counter the Easter Invasion in 1972.Mutza, 2004. p. 67

XM29 and the Sagami Mount The XM29 was an experimental door pintle for the main cabin doors of short fuselage UH-1s (at the time the UH-1B/C), for an M60D 7.62×51mm machine gun. The problem with this system was that it could not be used in conjunction with external armament subsystems.United States, 1969. p. B-2

Far more common on such helicopters, including the later UH-1F/P/M specifically, was the Sagami Mount, a skeleton frame mount that swung out from a fixed position at the rear of the cabin. This mount was designed for the M60D, but in certain instances, primarily by the US Navy Seawolves, dual M60 machine guns, M2HB machine guns or M134 Miniguns were fitted.

Sources debate the origin of the "Sagami" name, with it being attributed to the soldier responsible for its creation,Mutza, 2004. p. 26 as well as, to the name of the US facility on Okinawa where it was developed.US Army TACOM-RI. 5 October 2005 U.S. ARMY HELICOPTER WEAPON SYSTEMS (Page 2 of 2). Access Date: 7 May 2007

XM30 An experimental system, the XM30 provided fully flexible mounts using the XM156/M156 universal mounts for two XM140 30mm cannon, with 600 rounds of ammunition per gun.Gervasi, 1984. p. 242

XM31