Sometimes good things come from bad mistakes.........
In 1962, the U.S. Army decided that it needed an armed 'escort helicopter' to accompany the airborne assault force recommended by the Howze Board. The Army's utility and attack transport helicopter, the Bell UH-1, was about to be joined in Vietnam by armed versions of the same machine, the UH-1B. The UH-1B Iroquois was armed with rockets, machineguns and 40mm grenade launchers, but was not really the solution the Army was looking for. Out of these experiments came a requirement for an Advanced Aerial Fire Support System, a type of 'super' escort helicopter. Lockheed responded with the AH-65 Cheyenne, an truly advanced 'compound' helicopter (one which had a conventional propeller system as well as a lift-generating rotor); the main rotor of the Cheyenne was a rigid type, and this and many complex systems gave rise to delays and problems. Sadly, the program failed and the AH-65 was cancelled.
Out of the wreck of the AAFSS came a privately funded prototype from Bell, designed to satisfy the 'interim AAFSS', the less ambitious requirement from the U.S.Army. The Bell Model 209 HueyCobra was modified (broader rotor blades, substitution of retractable skids with fixed ones, etc). The '540' rotor head, drive train, and Lycoming T-53 turboshaft from the UH-1 Iroquois were mated with a SCAS (Stability Control Augmentation System) and an new incredibly slim fuselage, housing two crew members. The pilot in a raised cockpit behind the gunner, whose view from the front cockpit was unobstructed and made for easy aiming of the weapon systems. Maximum speed was 193 mph and the helicopter had a useful range of 425 miles. The first flight of what was to become the AH-1 took place on the 7th September, 1965, and it became obvious that this was what was needed in the growing war in South East Asia. Army orders ramped up quickly, so that by mid-1968, 838 AH-1 helicopters had been produced. By 1968, the 4th Aviation Battalion, 4th Infantry Division, based on Pleiku, were re-equipping from UH-1 Hueys to the AH-1G Cobra. Units like the 101st Aviation Battalion of the 101st Airborne Division were flying the developed AH-1G by 1971, (some of which were fitted with a 20mm cannon under the left stub wing), and were heavily involved in the fighting around the Laotian border.
The HueyCobra performed armed escort, fire suppression and interdiction roles. The chin turret from Emerson contained a 7.62 minigun or 40mm grenade launcher or a combination of these weapons;later a three-barrel 20 mm XM197 cannon was carried. The stub wings on either side of the cockpit were equipped with four hardpoints capable of carrying rockets (usually 2.75"), gun pods or TOW missiles.
Developed versions included the AH-1J for the United States Marine Corps leading to a whole family of HueyCobras with two engines - a requirement the Corps had insisted upon for improved safety in over-sea operations. As well as combat in Vietnam, the HueyCobra flew in numerous minor actions such as the invasion of Grenada, and around 400 Cobras of various marks even made major inroads into Iraqi armor during the First Gulf War in 1991. Highly maneuverable, I have heard it described as an aircraft that you didn't so much fly, as 'strap on'. This maneuverability caused the AH-1F to be chosen as the mount of the 'Sky Soldiers' Demonstration Team of the Army Heritage Foundation.
The AH-1 construction sequence moved through various models with major versions including the AH-1G and AH1-S. Paradoxically, the -S was refined through several steps to become the AH-1F (sometimes, retrograde 'naming' sequences happen, e.g. Tempest II versus Tempest V). The HueyCobra was supplied to many of America's allies, even those who lost that status afterwards, as was the case in 1971 when Iran acquired the AH-1J. The Iranians have since reverse engineered this type and made slight upgrades to produce the Toufan 2 (Storm 2). Israel has also received the HueyCobra in quantity.
Unusual duties for the AH-1 included 'Red Catcher Patrol', a constant watch on the Czechoslovak and East German borders at the height of the Cold War, to seek out possible infiltrators from the then-Communist states. An example of the units undertaking this little-known duty was the 4th Squadron of the 2nd Armored Cavalry.
Given the availability of older versions of the AH-1, it was natural that civilian applications would be found for this helicopter. The Washington State Department of Natural Resources uses the AH-1 to fight fires; some are equipped with an under-slung 'bucket'. Similarly, the U.S. Forest Service uses converted AH-1 airframes as the 'Firewatch Cobra' and the 'StarSafire' with upgraded communications and special IR sensors to see through smoke to the root of a fire. Garlick Helicopters has also converted the AH-1 into a model called the 'FireSnake'
Here we see something of an oddity. The British Army Museum of Flying at Middle Wallop is an excellent facility, but its primary focus lies (obviously) on equipment that the Army has flown (or, even, captured). It was therefore somewhat strange to find this U.S. Army AH-1F in the Museum's extension. It is shown as being equipped with the TOW missile system, 2.75" rockets and a 20 mm XM197 cannon. Despite the fact that Bell tried very hard to get the British Army to adopt the HueyCobra, the British stuck with the indigenous Westland Lynx for the battlefield attack role. Built in 1970 (construction number 20934), with a Lycoming T-53-L-703 turboshaft, this AH-1F was a gift to the Museum from the U.S. Department of Defense in 2003.
By any standard, the AH-1 has been spectacularly successful. Over 1,100 have been built, and whether you are referring to the SeaCobra, SuperCobra or KingCobra, the many versions performed superbly, and their 40 year plus service life shows no sign of ending soon. Truly, a classic helicopter.