User:Born2flie/Development (UH-1 Iroquois)

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Main article: UH-1 Iroquois#Development

The purpose of this page is to refactor the Development section of the main article.

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[edit] References

[edit] Development

Prior to the early 1950s, helicopters were powered by piston engines. Piston engines proved to be heavy and the main limiting factor in a helicopter's payload ability. With the advent of the turboshaft engine came a powerplant that was lightweight, but with a significantly higher power output. This power to weight ratio made turbine engines desirable for helicopter development to allow them to carry heavier payloads as well as have more power to travel faster. The United States Army, looking to replace its fleet of OH-13 Sioux aircraft used for medical-evacuation (MEDEVAC), intended to harness this new technology and initiated a design competition for a turbine-powered replacement MEDEVAC helicopter. 20 companies submitted designs in their bid for the contract, including Bell Helicopter with the Model 204 and Kaman Aircraft with a turbine-powered version of the H-43.

[edit] Model 204

On 23 February 1955, the Army announced its decision, selecting Bell to build three copies of the Model 204, designated the XH-40, for evaluation. The XH-40 first flew on 20 October 1956 at Forth Worth, Texas with Floyd Carlson, chief test pilot, at the controls.

The Huey dates to the mid-1950s, when the Army held a design competition to find a new medical-evacuation helicopter to replace the outdated Bell H-13, which had served the military well during the Korean War. The Bell Model XH-40 was in a dead heat with the Kaman H-43, but eventually became the helicopter of choice, principally because Bell Helicopter had produced the successful H-13. Backed by COL Spurgeon Neel, known as the "father of the Huey," the aircraft was many times pushed past its prescribed limits in real-world operations. It saw combat in Vietnam in a variety of roles.

Source

Feb. 23, 1955. The Army picks Bell Helicopter from a list of 20 competing companies to build its first turbine-powered helicopter. The winning design, designated XH-40, will become the HU-1 (and later still, UH-1) Iroquois, the renowned “Huey.” ... Oct. 26, 1956. Less than 16 months after design work began, and ironically, the same day that legendary designer Larry Bell dies, company pilot Floyd Carlson makes the first flight of the Bell XH-40 at Fort Worth, Tex. Later redesignated UH-1, the Iroquois, or “Huey” as it is more popularly known, will go on to be one of the significant helicopters of all time.

Source

The Iroquois was the first turbine power aircraft purchased by the Army and had the largest numbers produced of any helicopter for that era. It started out as the civilian model 204 and was designated XH-40 when the first three prototypes were ordered. The first of these was flown by Floyd Carlson at Fort Worth on 22 October 1956. Before this first flight, a service test batch of six YH-40s had been ordered and these were delivered by August 1958. When the H-40 was ordered into production, it was redesignated HU-1A in the Army category for utility helicopters and officially named the Iroquois.

Source

In 1955, anxious to obtain a powerful medical evacuation helicopter, the U.S. Army awarded Bell a contract to develop the next generation turbine-powered helicopter, designated the XH-40 (Bell company designation was the Model 204). The first XH-40 flew on October 22, 1956. Two more prototypes were built in 1957, and eighteen YH-40 prototypes were tested in 1958. In use, the UH-1A proved under-powered with their Lycoming T53-L-1 powerplants of just 860 shp and indicted the need for improved follow-on models of the Huey. Bell proposed the HU-1B

[vague], an improved model equipped with the Lycoming T53-L-5 engine, with 960 shp and a longer cabin that could accommodate seven passengers. Army testing of the HU-1B started in November 1960, with the first production aircraft arriving in March 1961.

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.

The UH-1C was specifically developed as a gunship version to correct the deficiencies of the UH-1B when it was used in the armed role. Bell fitted the UH-1C with a 1100 shp 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. The increased power led 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 UH-1C 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 gallons and gross weight to 9500 lbs, giving a nominal useful load of 4673 lbs.

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, designated "N9" and five for Norway. The balance went to the US Army.

Many UH-1Cs were later re-engined with the 1400 shp Lycoming T53-L-13 powerplant. With this engine they were redesignated UH-1M.

In 1962, the 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 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 October 7, 1963 and deliveries commenced February 21, 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 1100 shp. 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 UH-1C tailboom including the larger tail rotor pylon, the 540 rotor system and a gross weight of 8500 lbs.

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 1400 shp, 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.

[edit] H-48

The Bell H-48 [Bell 204B Huey] was used as 'missile site support' helicopter. On 7 June 1963 the U.S. Air Force named Bell Helicopter the winner of its competition held to select an "off-the-shelf' helicopter for missile site support. Built specifically for the Air Force, the UH-1F was based on the short-bodied model 204 and was a continuation of the UH-1B series initially known as the H-48 in the USAF designation system.

Source

Bell Helicopters was the winner of a 1963 United States Air Force (USAF) competition for a support helicopter for use on its missile bases. A specific requirement mandated the use of the General Electric T58 turboshaft as a powerplant. The USAF already had a large inventory of these engines for its fleet of HH-3 Jolly Green Giant rescue helicopters and wanted to have commonality between the types. 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 UH-1B with the longer tail boom, rotor and transmission of the UH-1D.

In Italy, Agusta produced a similar model by re-engining the 204B with the 1,225 hp (914 kW) Rolls-Royce Gnome turboshaft and later the UH-1F's General Electric engine. The Italian version was exported to the military of the Netherlands, Denmark, Austria, and Switzerland. It had a rescue hoist located at the right side of the cabin.

[edit] Model 205

The earlier "short-body" Hueys were a success, but the Army wanted a version that could carry a crew of four (two pilots and two door gunners) and also deliver an infantry section of 8-10 soldiers. Bell's solution was to stretch the UH-1B fuselage by 41 inches (105 cm) and use the extra space to fit four sideways-facing seats next to the transmission. This brought the total seating capacity to 15, including crew seats. 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 44 foot main rotor and a Lycoming T53-L-9 engine. Testing revealed that more power was required and so the rotor was lengthened to 48 feet with a chord of 21 inches and the engine was upgraded to the Lycoming T53-L-11 engine of 1100 shp. A longer tailboom was designed to accommodate the longer rotor blades. Gross weight was 9500 lbs. Later production "Deltas" had the Lycoming T53-L-13 powerplant of 1400 shp installed.

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 16 foot 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.

The UH-1H was an improved UH-1D, with the Lycoming T53-L-13 engine of 1400 shp installed, plus the pitot tube relocated from the nose to the roof, to reduce damage to it. "Hotel" models were created by upgrading "Deltas" as well as new production. 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 4850 delivered to the US Army alone. The "Hotel" model was widely exported and was also built under licence in Germany, Italy, Japan and Taiwan.

The "Hotel" model Huey was also the basis for a number of sub-variants:

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 "Mike" model Huey was a conversion of the existing UH-1C by re-engining it with the 1400 shp 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.

See main article UH-1N Twin Huey

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 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. 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 licence-built by Agusta in Italy and the Peoples Republic of China. Bell certified a civil version as the Model 212 in October 1970.

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 the "Papa" Hueys were in fact modified and employed as gunships armed with machine guns and rocket launchers.

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 radio altimeter, DME, ILS and a rescue hoist. The first aircraft were supplied to the New Hampshire Army National Guard.

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.

See main article UH-1Y Venom

The UH-1Y Venom is an upgraded UH-1N Twin Huey for the US Marines that was first flown on November 18, 2006.

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.

A total of 1010 "Bravo" models were delivered to the US Army. One NUH-1B was produced for test purposes. 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 2561 UH-1Ds were built, including 352 constructed by Dornier for the West German armed forces.

[edit] Operational history

Production UH-1A first entered service with the 101st Airborne 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 next UH-1A unit to arrive in Vietnam after the 57th Medical Detachment were with a new test unit, the U.S. 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 Shawnees and H-34 Choctaws troop carriers.

First deployment of the newer UH-1B followed the next year, November 1963, when eleven were sent to Vietnam to join the UH-1A models already in use by UTTCO.

The first Army unit deliveries of the "Delta" model were on August 9, 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.

The UH-1F was introduced into the USAF inventory on February 20, 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.

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.

Bell was awarded a contract by the United States 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 1400 shp Lycoming T53-L-13 engine.

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. A total of 27 HH-1Ks were produced.

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 May 16, 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 1400 shp.

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 500 lb bombs and 500 lb 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.

[edit] Canada

Ten UH-1H were sold to the government of Canada for use under the designation CUH-1H with the first one being delivered on March 6, 1968. The aircraft were evaluated by the Canadian Forces and found unsuitable for tactical use. In response, the Canadian government sponsored the development of the twin-engined version of the "Hotel", the UH-1N Twin Huey. The CUH-1Hs were modified for search and rescue duties, redesignated CH-118, and served until 1995, when they were replaced by ??.

[edit] Variants

[edit] U.S. Military

XH-40

The initial Bell 204 prototype. Three prototypes were built, equipped with the Lycoming XT-53-L-1 engine of 700 shp.

YH-40

Six pre-production aircraft.

One YH-40BF rebuilt as a flight test bed with turbofan engines and wings.

UH-1A

Initial Bell 204 production model, originally designated as HU-1A prior to 1962.

  • XH-1A

A single UH-1A was redesignated for grenade launcher testing in 1960.

UH-1B

Upgraded HU-1A, various external and rotor improvements. Originally designated HU-1B prior to 1962.

  • NUH-1B

a single test aircraft, serial number 64-1861.

UH-1C

UH-1B with improved engine, modified blades and rotor-head for better performance in the gunship role.

YUH-1D

Seven pre-production prototypes of the UH-1D.

UH-1D

Initial Bell 205 production model (long fuselage version of the 204). Designed as a troop carrier to replace the CH-34 then in US Army service.

  • HH-1D

Army crash rescue variant of UH-1D.

UH-1E

UH-1B/C for USMC with different avionics and equipment.

  • NUH-1E

UH-1E configured for testing.

  • TH-1E

UH-1C configured for Marine Corps training. Twenty were built in 1965.

UH-1F

UH-1B/C for USAF with General Electric T-58-GE-3 engine of 1325 shp. Due to the configuration of the T58 engine, Bell installed the engine backwards. The HH-3's engines are in front of the transmission, whereas the UH-1's engine is behind 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.

  • TH-1F

Trainer based on the UH-1F for the USAF.

UH-1G

UH-1D/H gunships operating with the Cambodia armed forces were locally given the designation UH-1G.[citation needed]

UH-1H

Improved UH-1D with a Lycoming T-53-L-13 engine of 1400 shp.

  • CUH-1H

Canadian Forces designation for the UH-1H utility transport helicopter. Redesignated CH-118.[1]

  • EH-1H

Twenty-two aircraft converted by installation of AN/ARQ-33 radio intercept and jamming equipment.

  • HH-1H

SAR variant for the USAF with rescue hoist.

  • JUH-1

Five UH-1Hs converted to SOTAS battlefield surveillance configuration with belly-mounted airborne radar.

  • TH-1H

Recently modified UH-1Hs for use as basic helicopter flight trainers by the USAF.

UH-1J

An improved Japanese version of the UH-1H built under license in Japan by Fuji was locally given the designation UH-1J.[citation needed]

HH-1K

Purpose built SAR variant of the Model 204 for the US Navy with USN avionics and equipment.

TH-1L

Helicopter flight trainer based on the HH-1K for the USN. Forty-five were built.

  • UH-1L

Utility variant of the TH-1L. Eight were built.

UH-1M

Gunship specific UH-1C upgrade with Lycoming T-53-L-13 engine of 1400 shp.

UH-1N

Initial Bell 212 production model, the Bell "Twin Pac" twin-engined Huey.

UH-1P

UH-1F variant for USAF for special operations use and attack operations used soley by the USAF 20th Special Operations Squadron, "the Green Hornets".

UH-1U

Single prototype for Counter Mortar/Counter Battery Radar Jamming aircraft. Crashed at Edwards AFB during testing.[citation needed]

UH-1V

Aeromedical evacuation, rescue version for the US Army.

EH-1X

Ten Electronic warfare UH-1Hs converted by under "Quick Fix IIA".

UH-1Y

Upgraded variant developed from existing upgraded late model UH-1Ns, with additional emphasis on commonality with the AH-1Z.

Note: In U.S. service, G, J, Q, R, T and Z models are used by the AH-1. The UH-1 and AH-1 are both considered members of the H-1 series.

[edit] Other militaries

Bell 204
Bell Helicopters company designation, covering aircraft from the XH-40, YH-40 prototypes to the UH-1A, UH-1B, UH-1C, UH-1E, UH-1F, HH-1K, UH-1L, UH-1P and UH-1M production aircraft.
  • Agusta-Bell AB 204
    Military utility transport helicopter. Built under licence in Italy by Agusta.
    Agusta-Bell AB 204AS
    Anti-submarine warfare, anti-shipping version of the AB 204 helicopter.
    Fuji-Bell 204B-2
    Military utility transport helicopter. Built under licence in Japan by Fuji Heavy Industries. Used by the Japan Ground Self Defence Force under the name Hiyodori.
Bell 205
Bell Helicopters company designation of the UH-1D and UH-1H helicopters.
  • Bell 205A-1
    Military utility transport helicopter version, initial version based on the UH-1H.
    Bell 205A-1A
    As 205A-1, but with armament hardpoints and military avoinics. Produced specifically for Israeli contract.
    Agusta-Bell 205
    Military utility transport helicopter. Built under licence in Italy by Agusta.
    Fuji-Bell 205A-1
    Military utility transport helicopter. Built under licence in Japan by Fuji. Used by the Japanese Ground Self Defence Force under the designation HU-1H.[citation needed]
Bell Huey II
A modified and re-engined UH-1H, significantly upgrading its performance, and its cost-effectiveness. Currently offered by Bell to all current military users of the type.