The Vietnam War’s iconic helicopter was the UH-1 utility helicopter, commonly called the Huey, the most widely used helicopter in the war and known as the workhorse of the Vietnam War. It was used by all military forces for troop transportation, medical evacuation, and combat assault, carrying soldiers and supplies to the lines as the horses for a modern cavalry. More than 7,000 Huey helicopters served in Vietnam and nearly half were lost. The first Hueys to operate in Vietnam were medevac HU-1As that arrived in April 1962, before the U.S. became officially involved in the conflict. In October, the first armed Hueys were equipped with 2.75-inch rockets and .30 caliber machine guns and began flying in Vietnam, mainly escorting Army and Marine transport helicopters as gunships. By the end of 1964, the Army was flying more than 300 A and B model Hueys. The Huey has a metal fuselage of semi-monocoque construction with tubular landing skids and two rotor blades on the main rotor, and early models featured a single Lycoming T53 turboshaft engine with power ratings from 700 shp to 1,4000 shp.