Bell AH-1 Cobra

AH-1 HueyCobra/Cobra

A Bell AH-1G HueyCobra
Role	Attack helicopter
Manufacturer	Bell Helicopter
First flight	7 September 1965
Introduction	1967
Status	Active service
Primary users	United States Army (historical) Japan Self Defense Forces Republic of Korea Army Israeli Air Force
Produced	1967-present
Number built	1,116
Unit cost	US$11.3 million (1995) (AH-1 HueyCobra)^[1]
Developed from	UH-1 Iroquois
Variants	AH-1 SeaCobra/SuperCobra Bell 309 KingCobra

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The AH-1 was the backbone of the United States Army's attack helicopter fleet, but has been replaced by the AH-64 Apache in Army service.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 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.^[2]

Development

Background

Closely related with the development of the Bell AH-1 is the story of the Bell UH-1 Iroquois—predecessor 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.^[3]

It soon became clear that the unarmed troop helicopters were vulnerable against ground fire from Việt Cộng 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.^[4]

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.^[5]

Iroquois Warrior and Sioux Scout

Bell Model 207 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 D 255 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-armor missiles.^[6]

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.^[7] The Sioux Scout had all the key features of a modern helicopter gunship: 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 believed the Sioux Scout was too small, underpowered, unsophisticated, and fragile to be of practical use.^[7]

AAFSS

Army's solution to the shortcomings of the Sioux Scout was to launch the Advanced Aerial Fire Support System (AAFSS) competition.^[7] The AAFSS requirement would give birth to the Lockheed AH-56 Cheyenne–a heavy battlefield helicopter that would prove to be over-ambitious, over-complex and over-budget, before being canceled 10 years later in 1972.^[7] 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 helicopter–survival would be ensured only by the right mix of speed, agility and weapons.

Model 209

Bell 209 prototype of the AH-1 Cobra series, with skids retracted (FAA no. N209J)

At the same time, despite the Army's preference for the AAFSS–for which Bell Helicopter was not selected to compete–Bell stuck with their own idea of a smaller and lighter gunship.^[7] 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.^[7] Bell's Model 209 largely resembled the "Iroquois Warrior" mockup.^[8]

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.^[7] 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.^[7]

On 3 September 1965 Bell rolled out the prototype, and four days later it made its maiden flight, only eight months after the go-ahead. In April 1966, the Model 209 won an evaluation against the other rival helicopters. Then the Army signed the first production contract for 110 aircraft.^[7] 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.^[9]

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.^[8]

Into production

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.^[8] 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.^[10]

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.^[11] 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 1973. After passing qualification tests the following year, Bell was contracted with upgrading AH-1Gs to the TOW-capable AH-1Q configuration. A more powerful T53 engine and transmission was added from 1976 resulting in the AH-1S version. The AH-1S was upgraded in three steps, culminating with the AH-1F.^[7]^[12]

Operational history

For AH-1J, AH-1T, AH-1W, AH-1Z and other twin-engine variants, see AH-1 SuperCobra.

Bell AH-1G over Vietnam

AH-1Q Cobra in Fort Hood, Texas

A late-model AH-1 Cobra at ILA 2006 in Berlin

United States

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.^[7] 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.^[8] 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.^[7] Out of nearly 1,110 AH-1s delivered from 1967 to 1973 approximately 300 were lost to combat and accidents during the war.^[8]^[13]

The US 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 the US invasion of Panama in 1989, during Operation Just Cause.^[8]

During Operation Desert Shield (1990) and Operation Desert Storm (Jan-Feb 1991), the Cobras and SeaCobras deployed in a support role. The USMC deployed 91 SeaCobras and the US Army 140 Cobras, generally fitted with engine inlet sand filters and operating from forward, dispersed sites in the desert. Three AH-1s were lost in accidents during fighting and afterward.^[8] Cobras destroyed hundreds of Iraqi armored vehicles and other targets in the fighting, though the Army relegated the Cobra to the patrol and scout roles.

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 throughout the 1990s.^[8] In December 1995, Cobras deployed to Bosnia with the U.S. Army's 1st Armored Division as a part of Operation Joint Endeavor.

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.^[7]^[14] 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.^[7] AH-1 Cobras continue to be in service with the US military, by the US Marine Corps, which operate twin-engine AH-1 SuperCobras.

Israel

The Israeli Air Force named its Cobras as the "Tzefa" (צפע), Hebrew for Viper.^[15] 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

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.^[16] 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 the mid-2000s.^[17]

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.^[18]

US Forest Service

In 2003, the US Forest Service acquired 25 retired AH-1Fs from the US Army.^[7] These have been designated Bell 209 and are being converted into Firewatch Cobras with infared and low light sensors and systems for real time fire monitoring.^[19]^[20] 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.^[7]

Variants

Single-engine

JGSDF AH-1S

U.S. Forest Service Bell 209 on the Bar Complex Fire in California. USFS photo.

Bell 209: Original AH-1G prototype with retractable skid landing gear. This model number is also used by the FAA for the civilian registration of former U.S. Army AH-1s used in firefighting service.

AH-1G HueyCobra: Initial 1966 production model gunship for the US Army, with one 1,400 shp (1,000 kW) Avco Lycoming T53-13 turboshaft.
JAH-1G HueyCobra: One helicopter for armament testing including Hellfire missiles and multi-barrel cannon.^[21]
TH-1G HueyCobra: Two-seat dual-control trainer.^[21]
Z.14 HueyCobra: Spanish Navy designation of the AH-1G.^[21]
YAH-1Q: Eight AH-1Gs with XM26 Telescopic Sight Unit (TSU) and two M56 TOW 4-pack launchers.^[8]
AH-1Q HueyCobra: Equipped with the M65 TOW/Cobra missile subsystem, M65 Telescopic Sight Unit (TSU), and M73 Reflex sight. All future versions will be equipped with the TSU and be equipped to fire the TOW missile subsystem.
YAH-1R: AH-1G powered by a T53-L-703 engine without TOW system.^[8]
YAH-1S: AH-1Q upgrade and TOW system.^[8]

AH-1S: The baseline AH-1S is an AH-1Q upgraded with a 1,800 shp (1,300 kW) T53-L-703 turboshaft engine. The AH-1S is also referred to as the "Improved AH-1S", "AH-1S Modified", or "AH-1S(MOD)" prior to 1988. (Prior to 1988, all upgraded aircraft were referred to as variants of the AH-1S.)^[8]
AH-1P: 100 production aircraft with composite rotors, flat plate glass cockpit, and improved cockpit layout for nap-of-earth (NOE) flight. The AH-1P is also referred to as the "Production AH-1S", or "AH-1S(PROD)" prior to 1988. These improvements are considered Step 1 of the AH-1S upgrade program.^[8]
AH-1E: 98 production aircraft with the Enhanced Cobra Armament System (ECAS) featuring the M97A1 armament subsystem with a three-barreled M197 20 mm cannon. The AH-1E is also referred to as the "Upgunned AH-1S", or "AH-1S(ECAS)" prior to 1988. These improvements are considered Step 2 of the AH-1S upgrade program.^[8] AH-1E aircraft included the M147 Rocket Management Subsystem (RMS) to fire 2.75-inch (70 mm) rockets.^[22]
AH-1F: 143 production aircraft and 387 converted AH-1G Cobras. The AH-1F incorporates all Step 1 and 2 upgrades to the AH-1S as well an M143 Air Data Subsystem (ADS), a laser rangefinder and tracker, an infrared jammer mounted above the engine exhaust, and an infrared suppressing engine exhaust system. The AH-1F is also referred to as the "Modernized AH-1S", "AH-1S Modernized Cobra", or "AH-1S(MC)" prior to 1988.

Model 249: Experimental demonstrator version fitted with a four-bladed rotor system, an uprated engine and experimental equipment, including Hellfire missiles.^[23]

Bell 309 KingCobra: Experimental version. One of two 309s produced was powered by a Lycoming T-55-L-7C engine.^[24]

Twin-engine

For all twin-engine variants, such as AH-1J, AH-1T, AH-1W, and AH-1Z, see AH-1 SuperCobra.

Operators

Operators of the AH-1 single-engined variant are shown in dark blue, the twin-engined variant in green, both variants in light blue and former operators in red.

For operators of AH-1J, AH-1T, AH-1W, AH-1Z and other twin-engine variants, see Bell AH-1 SuperCobra.

Current operators

Two Pakistani Army AH-1S Cobras at AVN Base, Multan

Three Israeli AH-1F Cobras over Masada

USFS Bell 209 at Fox Field during the California wildfires of October 2007

Bahrain

Bahrain Air Force acquired 24 AH-1Ps and 6 TAH-1P trainers.^[8] Bahrain has 10 AH-1Es, 6 AH-1Ps and 6 TAH-1Ps in inventory as of January 2010.^[25]

Israel

Israeli Air Force has 54 AH-1 "Tzefa" צפע ("Viper"), consisting of 5 AH-1G, 30 AH-1S, 6 AH-1E, and 13 AH-1F variants in inventory as of January 2010.^[25]

Japan

Japan Ground Self-Defense Force received 2 AH-1Es for exhaustive evaluation.^[8] 89 AH-1S Cobras were license-manufactured by Fuji Heavy Industries from 1984 to 2000.^[26] Has 84 AH-1S Cobras in use as of January 2010.^[25] JGSDF uses AH-1S Step 3 that were roughly equivalent the United States Army's AH-1Fs. The engine is the T53-K-703 turboshaft, which Kawasaki Heavy Industries produced under license.^[8]

Jordan

Jordanian Air Force received 24 AH-1Ss and 9 AH-1Fs.^[8] Jordan has 22 AH-1S and 9 AH-1F Cobras in use as of January 2010.^[25]

Pakistan

Pakistan Army received 20 AH-1S Cobras in the 1980s (later upgraded to AH-1F) and ordered more AH-1Fs in 2004.^[8] Pakistan has 18 AH-1S and 8 AH-1F Cobras in use as of January 2010.^[25] Pakistan ordered more Cobras in 2008 and received 14 AH-1Fs from United States in March 2010.^[27]^[28]^[29]

Philippines

Several reconditioned AH-1 Cobras were purchased for the Philippine Air Force from Israel.^[30]

South Korea

Republic of Korea Army received 42 AH-1S and 20 AH-1F Cobras.^[7] It has 50 AH-1S Cobras in service as of January 2010.^[25]

Thailand

Royal Thai Army received 4 AH-1Fs in 1990.^[8] The RTA has 2 AH-1Fs in use as of January 2010.^[25]

Turkey

Turkish Army received 32 used AH-1P/S Cobras. These were upgraded to AH-1F standards.^[7] The Turkish Army has 23 AH-1P Cobras in inventory as of 2010.^[25]

United States

U.S. Forest Service (25 AH-1Fs, converting to Bell 209 Firewatch Cobras)^[19]
Florida Division of Forestry (3 AH-1Ps, converting to Bell 209 "Firesnakes")^[7]

Former operators

Spain

Spanish Navy purchased eight new-build AH-1Gs, designating the type the "Z-14". These were equipped with the M35 20 mm cannon system, and were used to support coastal patrol boats. Four of these were lost in accidents. The remaining helicopters were retired in 1985 with three sent back to the US, and one kept in storage in Spain.^[31]

United States

United States Army replaced its AH-1s with AH-64 Apaches.
United States Customs Service used a small number of AH-1Gs between 1981 and 1986.
United States Marine Corps used AH-1Gs prior to delivery of AH-1Js.

Specifications

AH-1G HueyCobra

Data from Modern Military Aircraft,^[32] Verier,^[33] Modern Fighting Aircraft^[34]

General characteristics

Crew: 2: one pilot, one co-pilot/gunner (CPG)
Length: 53 ft (16.2 m) (with both rotors turning)
Rotor diameter: 44 ft (13.4 m)
Height: 13 ft 6 in (4.12 m)
Empty weight: 5,810 lb (2,630 kg)
Max takeoff weight: 9,500 lb (4,310 kg)
Powerplant: 1× Lycoming T53-L-13 turboshaft, 1,100 shp (820 kW)
Rotor system: 2 blades on main rotor, 2 blades on tail rotor
Fuselage length: 44 ft 5 in (13.5 m)
Stub wing span: 10 ft 4 in (3.15 m)

Performance

Never exceed speed: 190 knots (219 mph, 352 km/h)
Maximum speed: 149 knots (171 mph, 227 km/h)
Range: 310 nmi (357 mi, 574 km)
Service ceiling: 11,400 ft (3,475 m)
Rate of climb: 1,230 ft/min (6.25 m/s)

Armament

2 × 7.62 mm (0.308 in) multi-barrel Miniguns, or 2 × M129 40 mm Grenade launchers, or one of each, in the M28 turret. (When one of each was mounted, the minigun was mounted on the right side of the turret, due to feeding problems.)
2.75 in (70 mm) rockets - 7 rockets mounted in the M158 launcher or 19 rockets in the M200 launcher
M18 7.62 mm Minigun pod or XM35 armament subsystem with XM195 20 mm cannon

AH-1F "Modernized" Cobra

Data from Verier,^[33] Modern Fighting Aircraft^[34]