Staff Writer (Updated: 3/20/2016):
The Huey developed from advances made in turbine technology throughout the 1950's. Bell produced the turbine-powered Model 47 (XH-13F) in 1954 to which the United States Army took special interest in. The need for a MedEvac helicopter was on the US Army wish list and, as such, Bell was tagged with developing a solution - and the prototype XH-40 (Bell Model 204) was born. First flight of XH-40 occurred on October 22nd, 1956 and were followed by two additional XH-40 prototypes, fitting the Lycoming 700 horsepower XT-53-L-1 engine. A further six developmental models were then ordered as YH-40 evaluation aircraft. These were essentially the same as the XH-40 prototypes but had their cabin space extended a full 12-inches. One of these YH-40's was set aside as a test bed featuring turbofan engines and wing assemblies becoming Bell Model 533. The Model 204 entered production for the US Army as the HU-1A, becoming the first turbine-powered helicopter in service with any US military branch. First deliveries would fall to the 101st Airborne Division, the 57th Medical Detachment and the 82nd Airborne Division. The 57th Medical Detachment would be the first to field the system in Vietnam beginning in March 1962.
By all respects, design of the Huey was quite utilitarian although more pleasing to the eye that other rotary-wing offerings developed during the 1950s. Aircraft construction was comprised of the main fuselage housing the cockpit and passenger cabin (along with their associated systems and equipment), the engine and rotor mast section and the empennage, or tail section containing the tail rotor. The pilot and co-pilot were seated at the extreme forward of the design with a windowed cockpit providing excellent vision forward, above, to the sides and forward-below. Entry for either cockpit seating position was made through an automobile-style hinged door. The cabin featured a large sliding windowed door on either side of the fuselage for easy access (in most Vietnam-era pictures, these doors are almost always lest open). The single engine was mounted atop the rear portion of the crew cabin root with the rotor mast extending upwards forward of the engine. The rotor blades on initial models were simple two-blade arrangements with a rotor mast for added stability (the latest Huey version sports a four-blade rotor system). The engine exhausted rearwards over the base of the empennage. The tail section itself made up nearly half the length of the entire fuselage and featured horizontal fins about half-way down the tail section. The section ended with a single vertical fin adorned with the two-blade tail rotor system mounted to the portside (the latest Huey sports a four-blade tail rotor). The undercarriage consisted of a pair of fixed landing skids - braced in two areas - allowing for landing and take-off from just about any type of surface making it useful to both land and sea-based operators. Throughout its production run - with the exception of the twin-engine Huey - the base UH-1 Huey series would retain this unique and very identifiable design.
With its transport origins and inherently large cabin space, the Huey was designed from the outset to serve occupants in quantity. Passenger space was equivalent to 14 combat-ready troops. This arrangement could be supplanted by up to 6 medical litters when in the MedEvac role. The base crew could comprise 1 to 4 personnel as needed and depending on the role and equipment utilized.
The UH-1 airframe proved highly adaptable throughout its tenure, particularly when a showcase piece in the Vietnam War as helicopter gunships. Standard armaments included the use of pintle-mounted M60 7.62mm machine guns or specialized external mountings for dual 7.62mm miniguns mounts, 2-, 7-, or 19-shot 2.75" rocket pods and 7.62mm machine guns in quad-mountings. In the Vietnam War, US Army Hueys were dubbed "Cobras" when fitted with machine gun armament and "Hogs" when sporting rocket pods while unarmed Hueys became "Slicks" (similarly, the USN and USMC called their transports "Dolphins" and their gunships "Sharks"). Many other weapon arrangements were trialed with the Huey airframe throughout the Vietnam War resulting in a plethora of experimental systems with a laundry list of x-type designations. These trials included the use of air-to-surface missiles, 7.62mm minigun gun pods, 20mm and 30mm cannon armament, mine dispensers, heavy caliber 12.7mm miniguns and 40mm grenade launchers. In all, the series was already proving its adaptability to just about any role imaginable even though many of these impressive armament arrangements were never accepted into any official role.