The Bell AH-1 Cobra (company designation: Model 209) is a two-bladed, single engine attack helicopter manufactured by Bell Helicopter. It shares a common engine, transmission and rotor system with the older UH-1 Iroquois. The AH-1 is also referred to as the HueyCobra or Snake.
The AH-1 was the backbone of the United States Army's attack helicopter fleet, but has been replaced by the AH-64 Apache in Army service. Upgraded versions continue to fly with the militaries of several other nations. The AH-1 twin engine versions remain in service with United States Marine Corps (USMC) as the service's primary attack helicopter. Surplus AH-1 helicopters have been converted for fighting forest fires. The United States Forest Service refers to their program as the Firewatch Cobra. Garlick Helicopters also converts surplus AH-1s for forest firefighting under the name, FireSnake.
Closely related with the development of the Bell AH-1 is the story of the Bell UH-1 Iroquoispredecessor of the modern helicopter, icon of the Vietnam War and still one of the most numerous helicopter types in service today. The UH-1 made the theory of air cavalry practical, as the new tactics called for US forces to be highly mobile across a wide area. Unlike before, they would not stand and fight long battles, and they would not stay and hold positions. Instead, the plan was that the troops carried by fleets of UH-1 "Hueys" would range across the country, to fight the enemy at times and places of their own choice.
It soon became clear that the unarmed troop helicopters were vulnerable against ground fire from Vi?t C?ng and North Vietnamese troops, particularly as they came down to drop their troops in a landing zone. Without friendly support from artillery or ground forces, the only way to pacify a landing zone was from the air, preferably with a machine that could closely escort the transport helicopters, and loiter over the landing zone as the battle progressed. By 1962 a small number of armed UH-1As were used as escorts, armed with multiple machine guns and rocket mounts.
The massive expansion of American military presence in Vietnam opened a new era of war from the air. The linchpin of US Army tactics were the helicopters, and the protection of those helicopters became a vital role.
Iroquois Warrior and Sioux Scout
Bell had been investigating helicopter gunships since the late 1950s, and had created a mockup of its D-255 helicopter gunship concept, named "Iroquois Warrior". In June 1962, Bell displayed the mockup to Army officials, hoping to solicit funding for further development. The Iroquois Warrior was planned to be a purpose-built attack aircraft based on the UH-1B components with a new, slender airframe and a two-seat, tandem cockpit. It featured a grenade launcher in a ball turret on the nose, a 20 mm belly-mounted gun pod, and stub wings for mounting rockets or SS.10 anti-tank missiles.
The Army was interested and awarded Bell a proof of concept contract in December 1962. Bell modified a Model 47 into the sleek Model 207 Sioux Scout which first flew in July 1963. The Sioux Scout had all the key features of a modern attack helicopter: a tandem cockpit, stub wings for weapons, and a chin-mounted gun turret. After evaluating the Sioux Scout in early 1964, the Army was impressed, but also felt the Sioux Scout was undersized, underpowered, and generally not suited for practical use.
Army's solution to the shortcomings of the Sioux Scout was to launch the Advanced Aerial Fire Support System (AAFSS) competition. The AAFSS requirement would give birth to the Lockheed AH-56 Cheyennea heavy battlefield helicopter that would prove to be over-ambitious, over-complex and over-budget, before being canceled 10 years later in 1972. The Cheyenne program developed future technology and demonstrated some impressive performance, but was never made to work as a functional gunship. It served to underline an important rule of the combat helicoptersurvival would be ensured only by the right mix of speed, agility and weapons.
At the same time, despite the Army's preference for the AAFSSfor which Bell Helicopter was not selected to competeBell stuck with their own idea of a smaller and lighter gunship. In January 1965 Bell invested $1 million to proceed with a new design. Mating the proven transmission, the "540" rotor system of the UH-1C augmented by a Stability Control Augmentation System (SCAS), and the T53 turboshaft engine of the UH-1 with the design philosophy of the Sioux Scout, Bell produced the Model 209. Bell's Model 209 largely resembled the "Iroquois Warrior" mockup.
In Vietnam, events were also advancing in favor of the Model 209. Attacks on US forces were increasing, and by the end of June 1965 there were already 50,000 US ground troops in Vietnam. 1965 was also the deadline for AAFSS selection, but the program would become stuck in technical difficulties and political bickering. The U.S. Army needed an interim gunship for Vietnam and it asked five companies to provide a quick solution. Submissions came in for armed variants of the Boeing-Vertol ACH-47A, Kaman HH-2C Tomahawk, Piasecki 16H Pathfinder, Sikorsky S-61, and the Bell 209.
On 3 September 1965 Bell rolled out its Model 209 prototype, and four days later it made its maiden flight, only eight months after the go-ahead. In April 1966, the model won an evaluation against the other rival helicopters. Then the Army signed the first production contract for 110 aircraft. Bell added Cobra to the UH-1's Huey nickname to produce its HueyCobra name for the 209. The Army applied the Cobra name to its AH-1G designation for the helicopter.
The Bell 209 demonstrator was used for the next six years to test weapons and fit of equipment. It had been modified to the match AH-1 production standard by the early 1970s. The demonstrator was retired to the Patton Museum at Fort Knox, Kentucky and converted to approximately its original appearance.
The Bell 209 design was modified for production. The retractable skids were replaced by simpler fixed skids. A new wide-blade rotor was featured. For production, a plexiglass canopy replaced the 209's armored glass canopy which was heavy enough to harm performance. Other changes were incorporated after entering service. The main one of these was moving the tail rotor from the helicopter's left side to the right for improved effectiveness of the rotor.
The U.S. Marine Corps was interested in the Cobra and ordered an improved twin-engined version in 1968 under the designation AH-1J. This would lead to more twin-engine variants. In 1972, the Army sought improved anti-armor capability. Under the Improved Cobra Armament Program (ICAP), trials of eight AH-1s fitted with TOW missiles were conducted in October 1973. After passing qualification tests the following year, Bell was contracted with upgrading 101 AH-1Gs to the TOW-capable AH-1Q configuration. Following AH-1Q operational tests, a more powerful T53 engine and transmission were added from 1976 resulting in the AH-1S version. The AH-1S was upgraded in three steps, culminating with the AH-1F.
By June 1967, the first AH-1G HueyCobras had been delivered. Originally designated as UH-1H, the "A" for attack designation was soon adopted and when the improved UH-1D became the UH-1H, the HueyCobra became the AH-1G. The AH-1 was initially considered a variant of the H-1 line, resulting in the G series letter.
AH-1 Cobras were in use by the Army during the Tet offensive in 1968 and through the end of the Vietnam War. Huey Cobras provided fire support for ground forces, escorted transport helicopters and other roles, including aerial rocket artillery (ARA) battalions in the two Airmobile divisions. They also formed "hunter killer" teams by pairing with OH-6A scout helicopters. A team featured one OH-6 flying slow and low to find enemy forces. If the OH-6 drew fire, the Cobra could strike at the then revealed enemy. Bell built 1,116 AH-1Gs for the US Army between 1967 and 1973, and the Cobras chalked up over a million operational hours in Vietnam. Out of nearly 1,110 AH-1s delivered from 1967 to 1973 approximately 300 were lost to combat and accidents during the war. The U.S. Marine Corps used AH-1G Cobras in Vietnam for a short time before acquiring twin-engine AH-1J Cobras.
AH-1 Cobras were deployed for Operation Urgent Fury, the invasion of Grenada in 1983, flying close-support and helicopter escort missions. Army Cobras participated in Operation Just Cause, the US invasion of Panama in 1989.
During Operations Desert Shield and Desert Storm in the Gulf War (1990-91), the Cobras and SuperCobras deployed in a support role. The USMC deployed 91 AH-1W SuperCobras and the US Army 140 AH-1 Cobras; these were operated from forward, dispersed desert bases. Three AH-1s were lost in accidents during fighting and afterward. Cobras destroyed many Iraqi armored vehicles and various targets in the fighting.
Army Cobras provided support for the US humanitarian intervention during Operation Restore Hope in Somalia in 1993. They were also employed during the US invasion of Haiti in 1994. US Cobras were also used in operations later in the 1990s.
The US Army phased out the AH-1 during the 1990s and retired the AH-1 from active service in March 1999, offering them to NATO allies. The Army retired the AH-1 from reserves in September 2001. The retired AH-1s have been passed to other nations and to the USDA Forest Service. The AH-1 continues to be in service with the US military, by the US Marine Corps, which operate the twin-engine AH-1W SuperCobra and AH-1Z Viper.
The Israeli Air Force named its Cobras as the "Tzefa" (???), Hebrew for Viper. Since the mid-1970s Lebanon has been Israel's most active front. The Cobra helicopter's unique abilities and its precision weapons have made it perfect for the Lebanese theatre and IAF Cobras have been a constant feature of the fighting for more than 20 years. The first Cobra attack took place on 9 May 1979, near Tyre. Having crossed the border over the Mediterranean at dusk, two AH-1s scored direct hits with 2 missiles fired by each helicopter.
Cobra helicopter gunships were also used widely by the Israeli Air Force in the 1982 Lebanon War to destroy Syrian armor and fortification. IAF Cobras destroyed dozens of Syrian armored fighting vehicles, including many of the modern Soviet T-72 tanks. As part of their service in southern Lebanon the Cobras were very active in Israel's major operations against Hezbullah in operations "Accountability" and "Grapes of Wrath".
Pakistan was supplied with around 20 AH-1F gunships in 1983, these were later upgraded with the C-NITE thermal imaging package. Prior to that Iran had donated some AH-1 helicopters to Pakistan in mid 1970s, which Pakistan used as its main gunship helicopters against insurgents during the Balochistan conflict. The recent insurgencies in the Waziristan regions have seen Pakistani AH-1 gunships in action against Taliban and Al Qaeda fighters as well as their tribal allies. Pakistani gunships have also been used in operations against tribal uprisings in the Balochistan province, supporting the Pakistan Army against well-armed Bugti and Marri tribesmen under the late Nawab Akbar Khan Bugti and the Balochistan Liberation Army, since c. 2005.
Pakistan has several AH-1F and AH-1S Cobra attack helicopters. Sustainment of these aircraft is difficult, but possible through commercial channels. Additionally, the U.S. Government will use $75 million in FY 2009 Pakistan Counterinsurgency Funds to update a portion of the existing Cobra fleet. Pakistan will likely seek to replace its current AH-1 Cobras when the AH-1Z becomes available for export, probably in 2015.
US Forest Service
In 2003, the US Forest Service acquired 25 retired AH-1Fs from the US Army. These have been designated Bell 209 and are being converted into Firewatch Cobras with infrared and low light sensors and systems for real time fire monitoring. The Florida Division of Forestry has also acquired 3 AH-1Ps from the US Army. These are called Bell 209 "Firesnakes" and are equipped to carry a water/fire retardant system.
Source: Wikipedia (02/07/2012)