Bell UH-1 Iroquois
Design & Development:
Earlier helicopters had been powered by piston engines. By the early 1950s, however, turbine engines were being used in many fixed-wing aircraft and aircraft designers began to consider using them for rotary-wing use. Turbines, though expensive to build, were long-lived, durable, and extremely light for their power output in comparison to piston-powered engines.
XH-40 and YH-40
The first Bell helicopter to use a turbine engine was a modified Model 47 (designated the XH-13F), first flown in October 1954. 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 22 October 1956. Two more prototypes were built in 1957, and six YH-40 prototypes were tested in 1958.
Bell XH-40 prototype. (Source: U.S. Army)
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 of them.
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.[4] These aircraft were used as armed escorts to the existing H-21 Shawnees and H-34 Choctaws 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.
Continued on next page....
Sources:
Wikipedia: UH-1 Iroquois "Huey"
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