Bell UH - 1 Iroquois variants The following is an extensive catalog of the variants and specific unique elements of each variant and / or design stage of the UH - 1 Iroquois transport helicopter . XH - 40 and YH - 40 . The first Bell helicopter to use a turbine engine was a modified Model 47 ( designated XH - 13F ) , which had its initial flight in October 1954 . The U . S . Army began a competition for a new helicopter for general utility and medical / casualty evacuation in 1955 . In June 1955 , Bell Helicopter was awarded a contract to develop the next generation turbine - powered utility helicopter for the U . S . Army . The resulting Bell Model 204 was designated XH - 40 by the U . S . military and first flew on 22 October 1956 . Two more prototypes were built in 1957 , and six YH - 40 pre - production helicopters were delivered in 1958 . The YH - 40 ' s cabin was lengthened by , and had more ground clearance compared to the XH - 40 . Bell believed the YH - 40 was ideal for troop transport and cargo carrying as well as the medevac role , a view soon adopted by the Army , who found the pre - production aircraft so much better in service than previous piston - powered helicopters they soon ordered more . UH - 1A . The HU - 1A ( later redesignated the UH - 1A ) was the first turbine - equipped U . S . helicopter to go into production , and production models first entered service with the 101st Airborne Division at Fort Lewis , Washington , the 82nd Airborne Division and the 57th Medical Detachment . Although they were intended for evaluation only , the Army quickly pressed them into operational service and Hueys with the 57th Medical Detachment arrived in Vietnam in March 1962 . The helicopter was originally designated the HU - 1A , which is where it received its nickname - " Huey . " The official U . S . Army designation Iroquois ( Army helicopters are traditionally given Native American names ) was almost never used in practice . Fourteen of the original order of UH - 1As were designated as TH - 1A which were used for crew training and a single aircraft was redesignated XH - 1A for grenade launcher testing in 1960 . The first UH - 1As to arrive in Vietnam after the 57th Medical Detachment were with a new test unit , the US Army ' s Utility Tactical Transport Company ( UTTCO ) . UTTCO had 20 " Alpha " Hueys and deployed to Vietnam in the fall of 1962 . These aircraft were used as armed escorts to the existing H - 21 Shawnee s and H - 34 Choctaw s troop carriers . In use the UH - 1A proved under - powered with their Lycoming T53 - L - 1 powerplants of just 860 shp and indicated the need for improved follow - on models of the Huey . UH - 1B . The HU - 1B was an improved model that was equipped with the Lycoming T53 - L - 5 engine of , revised main rotor blades of diameter and chord , 13 inch higher rotor mast and a longer cabin that could accommodate seven passengers . This version was redesignated UH - 1B in 1962 . Later production UH - 1Bs were equipped with Lycoming T53 - L - 9 and L - 11 engines of . Gross weight was and the standard empty weight was . Army testing of the " B " model started in November 1960 with first production aircraft arriving in March 1961 . A total of 1010 " Bravo " models were delivered to the US Army . First deployment was in November 1963 when eleven were sent to Vietnam to join the " Alpha " models already in use by UTTCO . One NUH - 1B was produced for test purposes . Bell certified a civil version of the UH - 1B incorporating some minor safety improvements , such as improved door locks . The aircraft was marketed as the Bell 204B . UH - 1C . The UH - 1C was specifically developed as a gunship version until the " interim " attack helicopter , the Bell AH - 1G Huey Cobra was available and to correct the deficiencies of the UH - 1B when it was used in the armed role . The UH - 1C was widely referred to as the " Huey Hog " in US Army service . The " Charlie " model was fitted with the T53 - L - 9 or L - 11 engine to provide the power needed to lift the weapons systems in use or under development at the time . It incorporated the new Bell 540 rotor system with chord blades . The increased power lead Bell ' s engineers to design a new tailboom for the " C " which incorporated a wider chord fin on a longer boom and larger synchronized elevators . The " C " also introduced a dual hydraulic control system for redundancy in battle and an improved inlet filter system for the dusty conditions found in southeast Asia . Fuel was increased to 242 US gallon s and gross weight to , giving a nominal useful load of . Development on the " C " model had commenced in 1960 , with production starting in June 1966 . A total of 766 " C " models was completed , including five for the Royal Australian Navy and five for Norway . The balance went to the US Army . Many UH - 1Cs were later re - engined with the Lycoming T53 - L - 13 powerplant . With this engine they were redesignated UH - 1M . UH - 1D . The earlier " short - body " Hueys were a success , especially in the gunship role , but lacked the cabin space to be an effective troop transport . The US Army wanted a version that could carry a crew of four ( two pilots and two door gunners ) and also deliver an infantry section of eight - ten soldiers . Bell ' s solution was to stretch the UH - 1B fuselage by 41 inches ( 105 cm ) and use the extra space to fit two sideways - facing seats on either side of the transmission . This brought the total seating capacity to 15 , including crew seats . The new Huey was designated UH - 1D by the US Army and as the Model 205 by Bell . The enlarged cabin could also accommodate six stretchers , double that of the earlier models , making the " Delta " a good MEDEVAC aircraft . In place of the earlier model ' s sliding side doors with a single window , larger doors were fitted which had two windows , plus a small " hinged panel " with an optional window , providing access to the cabin . The doors and hinged panels were quickly removable and the Huey could be flown in that configuration . The first YUH - 1D prototype flew in August 1960 . Seven YUH - 1Ds were delivered and tested at Edwards AFB starting in March 1961 . The YUH - 1D was initially equipped with a main rotor and a Lycoming T53 - L - 9 engine . Testing revealed that more power was required and so the rotor was lengthened to with a chord of and the engine was upgraded to the Lycoming T53 - L - 11 engine of . A longer tailboom was designed to accommodate the longer rotor blades . Gross weight was . Later production " Deltas " had the Lycoming T53 - L - 13 powerplant of installed and redesignated as " Hotel " models . The first Army unit deliveries of the " Delta " model were on 9 August 1963 when the 11th Air Assault Division ( Test ) at Fort Benning Georgia received two . This unit was renamed the 1st Cavalry Division and deployed to Vietnam with its " Delta " Hueys . A total of 2008 UH - 1Ds were delivered to the US Army between 1962 and 1966 . The model was widely exported and served with the armed forces of Australia and South Vietnam among others . A grand total of 2 , 561 UH - 1Ds were built , including 352 constructed by Dornier for the West German armed forces . The HH - 1D was a base rescue / fire - fighting version for the US Army that had a 50 gallon water and foam spray system that could be discharged via an extendable boom . Upgrading the UH - 1D to the Lycoming T53 - L - 13 engine , plus relocating the pitot tube from the nose to the roof resulted in a new model , the UH - 1H , which was to become the most produced variant of the Huey family . UH - 1E . In 1962 the US Marines held a competition to choose a new assault support helicopter to replace the Cessna O - 1 and Kaman OH - 43D helicopter . The winner was the UH - 1B which was already then in service with the US Army . The UH - 1B was developed into a special model , designated UH - 1E , to meet Marine Corps requirements . The major changes included the use of all - aluminum construction for corrosion resistance ( earlier UH - 1s had some magnesium components ) , special avionics that were compatible with Marine Corps ground frequencies , a rotor brake to stop the rotor quickly on shutdown for shipboard use and a roof - mounted rescue hoist . The UH - 1E was first flown on 7 October 1963 and deliveries commenced 21 February 1964 , with 192 aircraft completed . Due to production line realities at Bell the UH - 1E was produced in two different versions , both with the same UH - 1E designation . The first 34 built were essentially UH - 1B airframes with the Lycoming T53 - L - 11 of . Because Bell was switching Army production to the UH - 1C the UH - 1E production line was converted to commonality with the “ C ” . This meant the later “ Echo ” Hueys were completed with the “ Charlie ” style tailboom including the larger fin , the 540 rotor system and a gross weight of . The Marines used the UH - 1E as both a gunship and troop transport . Many were upgraded to the Lycoming T53 - L - 13 engine which produced , making these “ Echos ” similar to the Army “ Mike ” models . At least 126 UH - 1Es survived their Vietnam service and were still in use more than a decade later . There was a Marine Corps training version of the UH - 1E , which was based on the UH - 1C variant and was designated TH - 1E . Twenty were delivered in 1965 . UH - 1F . Bell Helicopters was the winner of a 1963 United States Air Force competition for a support helicopter for use on its missile bases . Bell had proposed the UH - 1B for the competition but the USAF asked Bell to develop a special version of the " Bravo " in using the General Electric T58 turboshaft as a powerplant . The USAF already had a large inventory of these engines for its fleet of Sikorsky HH - 3 Jolly Green Giant rescue helicopters and wanted to have commonality between the types . This engine was capable of 1 , 250 hp ( 932 kW ) compared to the UH - 1B ' s 1 , 100 hp ( 820 kW ) T53 - L11 . In response Bell proposed an upgraded version of the UH - 1B with the T58 engine installed . The resulting UH - 1F had the shorter cabin of the " Bravo " Huey , but with the longer tail boom , rotor and transmission of the UH - 1D . Due to the Huey ' s configuration , Bell installed the T58 engine backwards compared to the HH - 3 . The Huey ' s engine is behind the transmission , whereas the HH - 3 ' s engines are in front of the transmission . Externally , the only visible differences from UH - 1B were the engine exhaust , which exited to the right side of the engine and the longer tail boom . The UH - 1F was introduced into the USAF inventory on 20 February 1964 . The USAF took delivery of 119 with production ending in 1967 . Many of the aircraft served in southeast Asia with the 20th Special Operations Squadron and some were converted to the armed UH - 1P configuration . In Italy , Agusta produced a similar model by re - engining the 204B with the 1 , 225 hp ( 914 kW ) Rolls - Royce Gnome ( license - built T58 ) turboshaft , but later models used T58s . The AB204B was exported to the military of the Netherlands , Sweden , Austria , and Switzerland . It had a rescue hoist located at the right side of the cabin . The last UH - 1F was retired from the USAF in the early 1980s when it was replaced by the UH - 1N . many of these aircraft later served as forest fire fighting aircraft with various US state governments and agencies . There was a TH - 1F trainer also built for the USAF . The first TH - 1F was flown in January 1967 and deliveries ran from April to July of that year with 27 completed . UH - 1H . The UH - 1H was an improved UH - 1D , with the Lycoming T53 - L - 13 engine of installed , plus the pitot tube relocated from the nose to the roof , to reduce ground damage to it . " Hotel " models were created by upgrading " Deltas " with the more powerful engine . The first YUH - 1H flew in 1966 with deliveries of production models starting in September 1967 . The " Hotel " model Huey was produced in larger numbers than any other model , with 4 , 850 delivered to the US Army alone . The " Hotel " model was widely exported and was also built under license in Germany , Italy , Japan and Taiwan . Ten were sold to Canada for use under the designation CUH - 1H with the first one was delivered on 6 March 1968 . These were evaluated by the Canadian Forces and found unsuitable for Canadian tactical use , which resulted in the Canadian government sponsoring the development of the twin - engined version of the " Hotel " , the UH - 1N Twin Huey . The ten CUH - 1Hs were re - equipped for search and rescue use , redesignated CH - 118 and served until 1995 . Bell developed a certified version of the UH - 1H for the civil market . The aircraft incorporated minor changes for safety , such as dual sliding door locks and a baggage compartment in the tailboom . It was marketed by Bell as the Model 205A and later the improved 205A - 1 . The " Hotel " model Huey was also the basis for a number of sub - variants : UH - 1J . Some UH - 1Hs built by Fuji in Japan were improved and given the local designation of UH - 1J , although this was not used in the US designation series . HH - 1K . Bell was awarded a contract by the US Navy in December 1968 for a new search and rescue helicopter . The aircraft was designated the HH - 1K and was basically a UH - 1E with different avionics and the Lycoming T53 - L - 13 powerplant of . Deliveries of the “ Kilo ” Huey started in May 1970 and by November of that year three had been sent to Vietnam to serve with US Navy squadron HA ( L ) - 3 and , later with the HA ( L ) - 4 Red Wolves and the HA ( L ) - 5 Blue Hawks . A total of 27 HH - 1Ks were produced . UH - 1L . With deliveries of the UH - 1E underway to the US Marines the US Navy tested a few and found that the type would suit their uses as a utility helicopter . On 16 May 1968 , the US Navy ordered eight aircraft under the designation UH - 1L . The “ Lima ” Huey was basically a UH - 1E , of the later production type based on the Army ' s UH - 1C , equipped with a rescue hoist and intake particle screen . The “ Ls ” were delivered without the armour or armament installed and were equipped with the Lycoming T53 - L - 13 powerplant of . The first four “ Limas ” were delivered in November 1969 and sent to Vietnam to equip the US Navy HA ( L ) - 3 detachment assigned to Operation Sealords . In Vietnam the aircraft were modified with weapons and armour and were fitted to carry bombs and Fuel - Air Explosive munitions . There was a TH - 1L version of the UH - 1L for the Navy to replace the H - 34 and the borrowed Army UH - 1Ds used in the training role , including for pilot aircraft carrier qualification training . Forty - five TH - 1Ls were delivered starting in November 1969 . UH - 1M . The " Mike " model Huey was a conversion of the existing UH - 1C by re - engining it with the Lycoming T53 - L - 13 powerplant used in the UH - 1H . This provided more power to the " C " model for its role as a gunship and also provided engine commonality between the attack and transport helicopters in use in Vietnam at that time . UH - 1N . Bell flew the first twin - engined Huey in April 1965 , calling it the Model 208 . It was powered by two Continental Motors engines . The Canadian government provided the incentive for Bell to continue development of the Twin Huey using Pratt & Whitney Canada PT6 engines . The project attracted orders from the Canadian Forces , US Marine Corps , US Navy and USAF , but not the US Army . The new aircraft was designated UH - 1N Iroquois in US service and CUH - 1N Twin Huey in Canadian Forces use . The Canadian designation was later changed to CH - 135 Twin Huey . There was an HH - 1N version produced for the USAF as a base rescue helicopter and for use by the 20th Special Operations Squadron in the counter - insurgency role using the call sign " Green Hornet " . Some Marine Corps UH - 1Ns were converted to VH - 1Ns as VIP transports , including six for Presidential use . The UH - 1N was widely produced and exported to a large number of countries and license - built by Agusta in Italy . Bell certified a civil version as the Model 212 in October 1970 . UH - 1P . An unknown number of UH - 1Fs were modified to UH - 1P configuration by the USAF for use by the their 20th Special Operations Squadron , The Green Hornets , based in southeast Asia during the Vietnam War . Official USAF sources state that these aircraft were used for a classified psychological warfare role , but this is incorrect . The " Papa " Hueys were in fact modified and employed as gunships armed with machine gun s and rocket launchers . UH - 1V . The UH - 1V is a version of the UH - 1H converted by the US Army Electronics Command for MEDEVAC use . The aircraft have several upgrades including a radar altimeter , DME , ILS and a rescue hoist . The first aircraft were supplied to the New Hampshire National Guard . EH - 1X . The EH - 1X was an improved EH - 1H that was equipped with the AN / ALQ - 151 system and configured for the airborne jamming , radio intercept and DF role . Ten EH - 1Xs were built starting in late 1976 under Project Quick Fix IIA . JUH - 1 SOTAS . The JUH - 1 was a modified UH - 1H an AN / APS 94 radar system mounted in a rotating boom on the belly , where the cargo hook had been . The aircraft ' s skid landing gear was modified to retract allowing the radar antennae to rotate while in flight . The JUH - 1s also incorporated an autopilot and improved navigation avionics . The radar system was connected by datalink to a ground station for analysis of the radar images . At least four UH - 1Hs were modified to JUH - 1s for use by the US Army in Europe and Korea for use as technology demonstrators in the Stand Off Target Acquisition System ( SOTAS ) program . They were first deployed in 1975 but by 1986 they had been replaced by the EH - 60 Black Hawk . UH - 1Y . The UH - 1Y Venom is an upgraded UH - 1N Twin Huey for the US Marines that was first flown on 18 November 2006 , developed as part of the H - 1 upgrade program . References . Listed in alphabetical order by author :