UH-1N Iroquois

The Bell UH-1N Twin Huey is a medium military helicopter that first flew in April, 1969.[1] The UH-1N has a fifteen seat configuration, with one pilot and fourteen passengers. In cargo configuration the UH-1N has an internal capacity of 220 ft³ (6.23 m³. An external load of 5,000 lb (2,268 kg) can be carried by the UH-1N.

Development

Based on the stretched fuselage Bell 205, the Bell 212 was originally developed for the Canadian Forces (CF) under the designation CUH-1N Twin Huey. Later the CF adopted a new designation system and the aircraft was re-designated as the CH-135 Twin Huey.[2] The CF approved the development of the aircraft on 1 May 1968[1] and purchased 50 aircraft, with deliveries commencing in May 1971.[3]
Canadian CH-135 Twin Hueys serving with the Multinational Force and Observers Sinai, Egypt 1989

The US military came very close to not procuring the Twin Huey. The purchase of the aircraft for US military use was opposed by the Chairman of the House Armed Services Committee at the time, Mendal Rivers. Rivers took this position because the aircraft powerplant, the Pratt & Whitney Canada PT6T was produced in Canada. The Canadian government had not supported US involvement in Vietnam and had opposed US policies in southeast Asia, as well as accepting US draft dodgers. Rivers was also concerned that procurement of the engines would result in a negative trade deficit situation with Canada. Congress only approved the purchase when it was assured that a US source would be found for the PT6T engines. As a result the United States military services ordered 294 Bell 212s under the designation UH-1N, with deliveries commencing in 1970.[3]

Unlike in the Canadian Forces, in US service, the UH-1N retained the official name "Iroquois" from the single engined UH-1 variants, although US service personnel refer to the aircraft as a "Huey" or "Twin Huey".[4]

The Bell 412 is a further development of the Bell 212, the major difference being the composite four-blade main rotor.[3]

[edit] Design
A USAF UH-1N during Exercise WOUNDED EAGLE '83
A Marine UH-1N sitting on the flight line at NAS Whiting Field, Florida, in 1982
U.S. Navy HH-1N from NAS China Lake at the Mojave Spaceport.

The UH-1N's main rotor is powered by a PT6T-3 Turbo Twin Pac made up of two Pratt & Whitney Canada PT6T turboshaft engines. They are capable of producing up to 1,342 kW (1,800 shp). Should one engine fail the remaining engine can deliver 671 kW (900 shp) for 30 minutes or 571 kW (765 shp) enabling the UH-1N to maintain cruise performance at maximum weight.[3]

The United States Marine Corps (USMC) modified a large number of their UH-1Ns with a Stability Control Augmentation System (SCAS) which provides servo inputs to the rotor head to help stabilize the aircraft during flight. This modification removed the gyroscopic "Stabilization Bar" on top of the main rotor head, instead relying on the computer system for stability.

[edit] Operational history

[edit] Military service

USMC UH-1Ns were used by the USMC during its 2003 invasion of Iraq. UH-1Ns provided reconnaissance, and communications support to Marine ground troops. They were also called upon to provide close air support during heavy fighting in Nasiriyah.[5]

[edit] Significant flights

On 6 March 1972, Hendrick V. Gorick of the United States Navy Antarctic Development Squadron Six (VXE-6) jumped at an altitude of 20,500 ft (6,248 m) from a UH-1N helicopter. In doing so he set a record for parachute jumping over the Antarctic continent.[citation needed]

[edit] Variants

[edit] U.S. variants

UH-1N Iroquois
Initial production model, used by the USAF, USN, and USMC. Over the years the primary operators, the USMC has developed a number of upgrades for the aircraft including improved avionics, defenses, and a FLIR turret.
VH-1N
VIP transport configuration[1]
HH-1N
SAR variant.[1]
UH-1Y Venom
Essentially a massive UH-1N replacement/upgrade for the USMC, designed to coincide with a similar upgrade for the AH-1W attack helicopter to AH-1Z Viper standard.

[edit] Foreign variants

Agusta-Bell AB 212
Civil or military utility transport version. Built under license in Italy by Agusta.
Agusta-Bell AB 121EW
Electronic warfare version for Turkey.
Agusta-Bell AB 212ASW
Anti-submarine warfare, anti-shipping version of the AB 212 helicopter, built under license in Italy by Agusta. Operated by the Italian Navy, Hellenic Navy and Islamic Republic of Iran Navy, Greece, Iran, Italy, Peru, Spain, Turkey, and Venezuela.[3]

The AB-212ASW is a Model 212 Twin Huey with a prominent radome above the cockpit. Early production had a dome-shaped radome, while later production had a flatter "drum" radome. A left side winch is used for dipping the Bendix ASQ-18 sonar. Other changes include structural reinforcement for a gross weight of 11,197 lbs (5080 kg), ECM, shipboard deck tie-down attachments and corrosion protection. Armament is two Mk 44 or Mk 46 torpedoes or two depth charges in the ASW role and four AS.12 air-to-surface wire-guided missiles for the anti-shipping role.[6][7]

CH-135 Twin Huey
Canadian version of the UH-1N.[1][3]
CUH-1N Twin Huey
Original Canadian Armed Forces designation for the UH-1N utility transport helicopter.[1][3]

[edit] Operators
Austrian UH-1N (Bell 212)
Canadian Coast Guard UH-1N (Bell 212)
The USAF's 20th Special Operations Squadron conducts a training exercise using a specially-painted UH-1N
Canadian CH-135 Twin Huey serving with 408 Tactical Helicopter Squadron 1985
AB.212 of Italian Air Force, airshow at Pratica di Mare AFB, Italy
A UH-1N helicopter, with Philippine Army officers aboard, prepares to land
United States Navy HH-1N Twin Huey, 2004

Angola

* Angolan Air Force (Bell 212)

Argentina

* Argentine Air Force (Bell 212)
* Argentine Army (Bell 212)

Austria

* Austrian Air Force (Agusta-Bell 212, Bell 212)

Bangladesh

* Bangladesh Air Force (Bell 212)

Bahrain

* Royal Bahraini Air Force (Bell 212)

Bolivia

* Bolivian Air Force (Bell 212)

Brunei

* Royal Brunei Air Force

Canada

* Canadian Forces (CH-135)
o 403 (Helicopter) Operational Training Squadron[8]
o 408 Tactical Helicopter Squadron[9]
o 422 Tactical Helicopter Squadron (disbanded 16 August 1980)[8]
o 424 Transport & Rescue Squadron[10]
o 427 Tactical Helicopter Squadron[11]
o 430 Tactical Helicopter Squadron (430e Escadron Tactique d'Hélicoptères)[12]
o 444 Combat Support Squadron[13]
o VU32 - Navy Utility Squadron[14]
o Aerospace Engineering Test Establishment[15]
o Base Flight Cold Lake[16]
o Base Rescue Goose Bay[13]
o Rotary Wing Aviation Unit, Canadian Contingent, Multinational Force and Observers, El Gorah Egypt, 1986-1990[17]
* Canadian Coast Guard (Bell 212)

Chile

* Chilean Air Force (Bell 212)

Colombia

* Colombian Air Force (Agusta-Bell 212)
* Colombian Army (UH-1N)
* Colombian Navy (Bell 212)
* Colombian Police (Bell 212)

Croatia

* Croatian Air Force (Agusta Bell 212)
* Croatian Police (Agusta Bell 212)

Dominican Republic

Ecuador

* National Police (Bell 212)

El Salvador

Germany

* German Federal Police (Bell 212)

Ghana

Greece

* Hellenic Air Force (Bell 212)
* Hellenic Army (Bell 212)
* Hellenic Navy (Bell 212ASW/EW)

Guatemala

Guyana

Indonesia

* Indonesian Army (Bell 212)

Iran

* Islamic Republic of Iran Army (Bell 212)
* Islamic Republic of Iran Air Force (Bell 212)
* Islamic Republic of Iran Navy (Bell 212ASW)

Israel

* Israeli Air Force

Italy

* Italian Air Force (Agusta-Bell 212)
* Italian Navy (Agusta-Bell 212ASW)
* Polizia di Stato (Agusta-Bell 212)

Jamaica

* Jamaica Defence Force (Bell 212)

Japan

* Japan Coast Guard

Jordan

Lebanon

Libya

Mexico

Morocco

Montenegro

Panama

Peru

* Peruvian Navy (Agusta-Bel 212ASW)

Philippines

Saudi Arabia

* Royal Saudi Air Force (Agusta-Bell 212)

Serbia

* Serbian Police

Singapore

* Used by Republic of Singapore Air Force for Search and rescue missions (retired in 1985, all three Bell 212s were sold to Sri Lanka).

Somalia

South Korea

Spain

* Spanish Army (Agusta-Bell 212)
* Spanish Navy (Agusta-Bell 212ASW)

Sri Lanka

* Sri Lanka Air Force (Bell 212)

Sudan

Thailand

* Royal Thai Air Force (Royal Flight)
* Royal Thai Army
* Royal Thai Navy (Bell 212)
* Royal Thai Police Wing

Tunisia

Turkey

* Turkish Army (Agusta-Bell 212)
* Turkish Navy (Agusta-Bell 212ASW)

Uganda

United Arab Emirates

United Kingdom

* Army Air Corps (Bell 212)

United States

* United States Air Force
* United States Marine Corps
* United States Navy

Uruguay

Venezuela

Yemen

Zambia

[edit] Specifications (USMC UH-1N, as modified)
U.S. Navy HH-1N cockpit.
HH-1N rotor head.

Data from USMC UH-1N Fact Sheet,[18] The International Directiory of Military Aircraft, 2002-2003[19]

General characteristics

* Crew: 4 (Pilot, copilot, crew chief, gunner)
* Capacity: 6-8 combat-equipped troops, or equivalent cargo
* Length: 41 ft 8 in (12.69 m)
* Rotor diameter: 48 ft 0 in (14.6 m)
* Height: 14 ft 5 in (4.4 m)
* Disc area: 1,808 ft² (168.0 m²
* Empty weight: 6,000 lb (2,721.5 kg)
* Loaded weight: 10,500 lb (4,762.7 kg)
* Useful load: 4500 lb (2038.0 kg)
* Max takeoff weight: 10,500 lb (4,762.7 kg)
* Powerplant: 2× Pratt & Whitney Canada T400-CP-400 turboshaft, 900 shp (671 kW), (total 1,250 shp) each

Performance

* Maximum speed: 120 knots (135 mph, 220 km/h)
* Cruise speed: 110 knots (126 mph, 207.3 km/h)
* Range: nmi (286 mi, 460 km)
* Service ceiling 17,300 ft (5,273 m)
* Rate of climb: 1,755 ft/min (8.9 m/s)
* Power/mass: hp/lb (W/kg)Armament
* 2.75-inch rocket pods,
* GAU-16 .50 Cal. Machinegun,
* GAU-17 7.62mm minigun or M240 7.62mm lightweight machinegun