|Bell Model 205 / UH-1 "Iroquois"|
Although basically similar to the earlier Model 204, the Model 205 introduced a longer fuselage, increased cabin space to accommodate a much larger number of passengers, and other changes. The military version of the Model 205 retains the Iroquois name, while the commercial utility version is designated Model 205A-1.
The initial production version for the US Army was the UH-1D powered by an 1100shp Lycoming T53-L-11 turboshaft engine, driving a 14.63m rotor. Accommodation provided for a pilot and 14 troops, or six stretchers and a medical attendant, or 1815kg of cargo. The first YUH-1D flew on 16 August 1961 and delivery to Army units began two years later. A further 352 UH-1Ds were built subsequently under licence in Germany for the German Army and Air Force. The UH-1D was followed into production by the UH-1H powered by an 1400shp T53-L-13 engine. By 1976 1242 had been built, including nine for the RNZAF. Production continues to meet export orders. A further 118 were built under licence in the Republic of China. Originally designated CUH-1H, ten similar helicopters were acquired for the Mobile Command, Canadian Armed Forces; subsequently redesignated CH-118. The designation HH-1H applies to 30 USAF helicopters (similar to UH-1H) for local base rescue.
The commercial Model 205A-1 is a 15-seat utility helicopter developed from the UH-1H, with a T5313B engine derated to 1250shp. It is designed for rapid conversion for alternative air freight, flying crane, ambulance, rescue and executive roles. External load capacity in the flying crane role is 2268kg. It is also licence-built by Agusta-BelI.
M.Taylor "Jane's Encyclopedia of Aviation", 1989
The undoubted success of the Bell UH-1A/B Iroquois gave convincing proof that there was little wrong with the basic design of this utility helicopter. As detailed in the Model 204 entry, the UH-1A/B was developed continuously for differing roles and with progressively more powerful engines.
In early 1960 Bell proposed an improved version of the Model 204 design with a longer fuselage, plus additional cabin space resulting from relocation of the fuel cells, thus providing accommodation for a pilot and 14 troops, or space for six stretchers, or up to 1814kg of freight. In July 1960, therefore, the US Army awarded Bell a contract for the supply of seven of these new helicopters for service tests, these having the US Army designation YUH-1D and being identified by the manufacturer as the Bell Model 205. The first of these flew on 16 August 1961, and following successful flight trials was ordered into production for the US Army, the first UH-1D being delivered to the 11th Air Assault Division at Fort Benning, Georgia, on 9 August 1963. The powerplant of these initial aircraft was the 820kW Avco Lycoming T53-L-11 turboshaft, and the standard fuel storage of 832 litres could be supplemented by two internal auxiliary fuel tanks to give a maximum overload capacity of 1968 litres of fuel. Large-scale production of the UH-1D followed for the US Army, as well as for the armed forces of other nations, and 352 were built under licence by Dornier in West Germany for service with the German army and air force.
The UH-1D was followed into production, by the more or less identical UH-1H which differed, however, in the use of the more powerful 1044kW Avco Lycoming T53-L-13 turboshaft engine. Delivery of the UH-1 H to the US Army began in September 1967, and this variant proved to be the final production version.
The UH-1H was built extensively for the US Army, nine were supplied to the RNZAF, and under the terms of licence agreement which was negotiated in 1969, the Republic of China (Taiwan) produced a total of 118 of these aircraft for service with the Nationalist Chinese army. Variants of the UH-1H include the CH-118 (originally CUH-1H) built by Bell for the Canadian Armed Force's Mobile Command, with the first of 10 being delivered on 6 March 1968; and the HH-1H local base rescue helicopter of which 30 were ordered for the USAF on 4 November 1970, deliveries being completed during 1973.
The UH-1D/H was employed extensively on a very wide range of duties in South East Asia, and was regarded by many as the workhorse helicopter par excellence in Vietnam. In particular, the type played a major role in special warfare operations in Laos, Cambodia, and in some of the remote areas of South Vietnam, and USAF historians have commented that in this latter theatre of operations nearly all battlefield casualties were evacuated by UH-1 helicopters.
Since that time, a small number of UH-1Hs have been selected to fulfill an electronic counter-measures role under the designation EH-1H, and examples with advanced systems were being delivered from 1981. Under the US Army's Stand-Off Target Acquisition System (SOTAS) programme, four UH-1Hs were modified for evaluation. Their role was to obtain radar data of battlefield movements, relaying them to commanders on the ground and providing real-time information on the tactical situation.
However, the US Army intends to retain the basic UH-1H in large-scale service until the beginning of the 21st century, for deployment in roles that include command and control, electronic warfare, medical evacuation, minefield emplacement, resupply, and troop transport. In order to make this plan possible, the existing fleet of UH-1Hs is the subject of a major product improvement programme which adds advanced avionics and equipment to give these helicopters the necessary capabilities and extended life.
Bell also produces a commercial version of the UH-1H under the designation Model 205A-1. It is powered by a 1044kW Avco Lycoming T5313B turboshaft, derated to 932kW. Normal fuel capacity of the Model 205A-1 is 814 litres, with an optional fuel capacity of 1495 litres. Because it is intended for a wide range of users, special attention has been given to interior design to permit quick conversion for air freight, ambulance, executive, flying crane and search roles. Maximum accommodation is for a pilot and 14 passengers.
Agusta in Italy also builds the Model 205 under licence with the designation AB 205A-1, this being virtually the same as the Bell production model. Customers have included the Italian armed forces, as well as those of several other countries. In Japan the Fuji-Bell Model 205A-1 is available.
D.Donald "The Complete Encyclopedia of World Aircraft", 1997
Although basically similar to the earlier Model 204, the Model 205 introduced a longer fuselage, increased cabin space to accommodate more passengers as well as other changes.
CH-118: Similar to UH-1H, for Mobile Command, Canadian Forces. First of 10 delivered on 6 March 1968. Originally designated CUH-1H.
EH-1H: Electronic countermeasures configuration, with the Quick Fix I airborne communications interception, emitter locating and jamming system, including an AN/APR-39(V)2 radar warning receiver, XM130 chaff/flare dispenser and AN/ALQ-144 infra-red jammer. The FY81 budget added US$5.1 million to convert initial Quick Fix IA systems in the EH-1H to Phase IB configuration, plus survivability equipment to protect the aircraft against known and postulated threats, including hot metal/plume suppression. However, the Quick Fix mission has been taken over by the much larger Sikorsky EH-60A version of the Black Hawk utility transport helicopter.
HH-1H: It was announced on 4 November 1970 that a fixed price contract worth more than US$9.5 million had been received from the USAF for 30 HH-1H aircraft (generally similar to the UH-1H) for use as local base rescue helicopters. Deliveries were completed during 1973.
UH-1D: This US Army version of the Model 205 Iroquois has an 820kW Lycoming T53-L-11 turboshaft, 14.63m rotor, normal fuel capacity of 832 litres and overload capacity of 1,968 litres. Relocation of the fuel cells increased cabin space to 6.23m3, providing sufficient room for a pilot and 12 troops, or six litters and a medical attendant, or 1,815kg of freight. A contract for a service test batch of seven YUH-1Ds was announced in July 1960 and was followed by further very large production orders from the US Army and from many other nations of the non-Communist world. First YUH-1D flew on 16 August 1961 and delivery to US Army field units began on 9 August 1963. The UH-1D was superseded in production for the US Army by the UH-1H, but 352 UH-1Ds were built subsequently under licence in Germany for the German Army and Air Force. Prime contractor was Dornier.
UH-1H: Following replacement of the original T53-L-11 turboshaft by the 1,044kW T53-L-13, the version of the Model 205 for the US Army was designated UH-1H. Deliveries of an initial series of 319 aircraft for the US Army began in September 1967. Another 914 ordered subsequently in several batches, with delivery extending into 1976. Under a licensing agreement concluded in 1969, the Republic of China produced UH-1Hs for the Nationalist Chinese Army, with much of the manufacturing and assembly process carried out at Taichung, Taiwan. Total procurement 118.
UH-1V: Approximately 220 UH-1Hs converted by US Army as a medevac version. Avionics and equipment in this version include a radio altimeter, AEL AN/ARN-124 DME, glide slope and rescue hoist.
The 7,000th Model 205/205A helicopter was completed in 1973.
AB 205A: Agusta-built version of the Bell 205 UH-1D. Also built in Germany by Dornier.
Model 205A-1: Civil and export designation of UH-1H. Also built in Italy by Agusta, Japan by Fuji and Taiwan by AIDC. First flight 22 March 1967; FAA certification 25 October 1968. A total of 332 produced by Bell at Fort Worth, Texas between 1968 and 1980.
AB 205A-1: Agusta-built Bell Model 205A-1 (UH-1H).
US Army: The US Army plans to retain at least 2,700 improved UH-1Hs in service beyond 2000 to perform such operations as resupply, troop transport, command and control, electronic warfare, medical evacuation and minefield emplacement. To make such a plan realistic, a product improvement programme for the army's UH-1H fleet introduced improved or new avionics and equipment including an AN/ALQ-144 infra-red jammer, AN/APN-209 radar altimeter, AN/APR-39 radar warning receiver, AN/ARC-164 UHF/AM radio, AN/ARN-124 DME, XM130 chaff/flare dispenser, NOE communications (FM/HF), communications security, infra-red suppressor (hot metal and plume), altimeter lighting (5V), crashworthy auxiliary fuel system, closed-circuit refuelling, fuel tank vent, improved main input drive shaft and main rotor mast plug. In addition, it is planned to introduce, as a minimum, new composite main rotor blades; improved stabiliser bar, tail rotor hub and servo cylinders; a split engine deck, and improved oil filtration; a night vision compatible cockpit; built-in Vibrex connections; an improved AN/ASN-43 gyromagnetic compass; and Doppler navigation.
A US Army Request for Proposal for composite main rotor blades for the UH-1H was issued on 16 November 1981. The army's schedule called for a qualified blade to be ready for production after 32 months. Procurement of 6,000 blades was anticipated in 1985-89, at a cost of US$20,000 or less per blade in FY81. Bell tendered a joint proposal with Boeing, and this team was awarded a US$19 million development contract during 1982 by the US Army Aviation Research and Development Command. Bell designed the composite blade for the UH-1H, but both companies fabricated test blades and supported laboratory and flight testing to ensure compliance with army requirements. The composite rotor blades provide a 6% improvement in the UH-1H's hovering capability and a 5 to 8 per cent reduction in fuel flow in forward flight. Bell provided manufacturing tools and fixtures and transferred specific manufacturing knowledge to Boeing, so that both companies were equally capable and qualified to manufacture production blades, for which contracts are expected to exceed US$100 million. The first flight of the composite rotor blades on a UH-1H took place in early 1985. Production deliveries began in January 1988.
The following description refers specifically to the military UH-1H:
DESIGN FEATURES: Two-blade semi-rigid main rotor. Stabilising bar above and at right angles to main rotor blades. Underslung feathering axis head. Two-blade all-metal tail rotor. Shaft drive to both main and tail rotor. Transmission rating 820kW. Main rotor rpm 294 to 324.
FLYING CONTROLS: Small synchronised elevator on rear fuselage is connected to the cyclic control to increase allowable CG travel.
STRUCTURE: Interchangeable main blades built up of extruded aluminium spars and laminates. Tail rotor blades of honeycomb construction. Blades do not fold. The fuselage is a conventional all-metal semi-monocoque structure.
LANDING GEAR: Tubular skid type. Lock-on ground handling wheels and inflated nylon float bags available.
POWER PLANT: One 1,044kW Textron Lycoming T53-L-13 turboshaft, mounted aft of the transmission on top of the fuselage and enclosed in cowlings. Five interconnected rubber fuel cells, total capacity 844 litres, of which 799 litres are usable. Overload fuel capacity of 1,935 litres usable, obtained by installation of kit comprising two 568 litre internal auxiliary fuel tanks interconnected with the basic fuel system.
ACCOMMODATION: Pilot and 11 to 14 troops, or six litters and a medical attendant, or 1,759kg of freight. Crew doors open forward and are jettisonable. Two doors on each side of cargo compartment; front door is hinged to open forward and is removable, rear door slides aft. Forced air ventilation system.
AVIONICS AND EQUIPMENT: FM, UHF, VHF radio sets, IFF transponder, Gyromatic compass system, direction-finder set, VOR receiver and intercom standard. Optional nav/com systems. Standard equipment includes bleed air heater and defroster, comprehensive range of engine and flight instruments, power plant fire detection system, 30V 300A DC starter/generator, navigation, landing and anti-collision lights, controllable searchlight, hydraulically boosted controls. Optional equipment includes external cargo hook, auxiliary fuel tanks, rescue hoist, 150,000 Btu muff heater.
Jane's Helicopter Markets and Systems
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- The original Huey, a Bell 204, flew for the first time in 1956.
- The 'Huey' nickname comes from the original U.S. Army HU-1 designation.