In 1952 the US Army identified a requirement for a new helicopter to serve in the medical evacuation, instrument flight training and light utility role, as the machines in the inventory at that time didn’t meet the Army’s demands. In November 1953 20 aviation companies participated in the competition for the new helicopter contract, among them was the Bell Helicopters company, which won with their entry, the Model 204, in June 1955.
The contract to develop and build three helicopter prototypes, designated XH-40 by the US Army was completed in 1956, first flights of the new helicopter type were conducted in October. Their success led to an order, placed at Bell Helicopters, for six machines of the pre-production series, designated YH-40. The cabin of those helicopters was stretched 12 inches in comparison to the XH-40 (the “pillar” between the pilot’s and cabin door was widened), to accommodate two stretchers. Operational tests, for which those machines were used, proved that the new helicopters not only met, but sometimes even surpassed the customer’s requirements.
On 23rd of February, 1959 the serial production of Model 204 for the US Army started under the designation HU-1A. Officially this helicopter was named “Iroquis”, but the name that was (and still is) in popular use, was “Huey”, coming from the designation’s HU letters (from Helicopter, Utility). First line units using the new craft were 82nd Airborne Division, 101st Airborne Division and the 57th Medical Unit – which was sent to Vietnam in 1962 as the first unit using the “Huey”. HU-1A had a 570 kW (770 hp) engine, crew of three and could carry four passengers.
Already in the moment, when first HU-1A’s were delivered, US Army signaled the need to equip them with stronger engines and develop new variants of the helicopter. Addressing those requirements was the new HU-1B helicopter. Its prototype was first flown in October 1960 and the serial production was started in March 1961. In 1962 the aircraft type designation system used by American armed forces was reformed, and under the new system the HU-1s became UH-1s. UH-1B was the first “Huey” variant factory-equipped to carry armaments. Its cabin was enlarged again in relation to HU-1A, so that the new helicopter could now carry seven passengers and the new engine, T53-L-5 had the power of 720 kW (960 hp). Additionally, the main rotor was strengthened and installed on a higher shaft.
Even this increase of engine power wasn’t sufficient, if the helicopter was to be used in the Gunship role, as it was envisioned in the new, Airmobility concept. To address this issue, work on yet another variant, UH-1C commenced in 1960. This version was designed to be used as air support for the troops fighting on the ground. The propulsion of this helicopter variant was a T53-L-11 engine with 820 kW (1100 hp) power, brand new main rotor, with wider blades attached to a newly designed, type 540 rotor head, also doubled hydraulic steering mechanisms and wider horizontal and vertical stabilizers.
The diorama on display shows a UH-1B helicopter belonging to US Army in Vietnam. UH-1s were used in Vietnam since 1962, at first for medical evacuation, later for transport at the disposal of the US military advisors working together with ARVN (Army of the Republic of Vietnam) and finally for transport, supply and air support of American combat troops. The helicopter shown on the diorama is painted in “high visibility” scheme, typical for the early period of American involvement in Vietnam. Later in the war more subdued markings were used. This had to take into account the contradiction between the desire to keep the helicopter well visible from above in case it failed or was shot down, on the other hand it was desirable to conceal it from the enemy. Solving this problem took experience, that was often paid in blood – which is shown by the displayed diorama
| Length (fuselage): | 16 130 mm |
| Height: | 4430 mm |
| Rotor diameter: | 13 390 mm |
| Empty weight: | 2042 kg |
| Maximum weight: | 5083 kg |
| Propulsion: | One 720 kW Lycoming T53-L-5 turboshaft engine |
| Armament: | Two M60 7,62mm machine guns on flexible mounts in cargo bay doors optionally supplemented by various armament packages |
| Range: | 407 km |
| Max speed: | 202 km/h |
| Crew: | 3/4 people (aircraft commander, second pilot, crew chief and optionally a machine gunner) |
