The leverage of technology: the evolution of armed helicopters in Vietnam

Military Review, July-August, 2003 by David G. Tyler

FEW MACHINES exemplify 20th-century technology like the helicopter. The complexity of a combat helicopter is phenomenal. Each airframe consists of thousands of parts that are machine-milled to precise specifications and operate in unison with little margin for error. To build a machine capable of sustained flight with rotating wings is remarkable in itself; to then use the machine in highly choreographed military operations ranks among the great accomplishments in modern warfare.

In the 20th century, the U.S. military embraced technology as a means of exploiting an advantage over enemy forces. In the Vietnam war, for example, the challenges of fighting a technologically inferior, unconventional enemy over a period of years provided a proving ground for technology-based weapons. Propelled by the urgency of war, the helicopter emerged as a major component of U.S. warfighting doctrine.

Introducing the helicopter as a means of leveraging technology shook the force structure of the U.S. Army to its foundation. Within the context of this transformation, the evolution of the armed helicopter is a revealing story.

The Backdrop

Following the Viet Cong (VC) capture of Phuoc Vinh in September 1961, President John F. Kennedy sent Army Chief of Staff Maxwell Taylor to Saigon to evaluate the situation. Taylor observed that the Army of the Republic of Vietnam (ARVN) suffered from inadequate mobility. Mountains and jungle in the north-central regions and a maze of rivers in the Mekong Delta severely retarded the country's road infrastructure. The Kennedy administration moved quickly to overcome the problem, believing that providing ARVN forces with U.S.-piloted helicopters would shift the balance of the conflict. The arrival of 32 Army H-21s in Saigon on 12 December 1961 signaled the beginning of a new era in military aviation. The tempo picked up in April 1962 when the helicopter carrier USS Princeton began launching Marine Corps H-34 helicopters on missions into South Vietnam. (1) By the end of September 1964, the CH-21 had been supplanted with 250 UH-1s and 9 CH-37s. (2)

Meanwhile, Secretary of Defense Robert McNamara directed the Army to evaluate its aviation requirements. Following an introspective study, the Howze Board released a report in August 1962 that called for the establishment of the 11th Air Assault Division, which eventually merged with the 2d Infantry Division and was renamed the 1st Cavalry Division (Airmobile). (3) General Hamilton Howze based his vision for an airmobile division on large-scale conventional war planning, not the counterinsurgency role found in Vietnam. Howze saw the primary advantages of the airmobile forces as mobility, utility in delay operations, the ability to ambush conventional forces, and the ability to provide direct firepower. (4) The unification of helicopters and ground forces gave a single commander incredible maneuverability and firepower. For example, the 1st Cavalry arrived in Vietnam with 15,787 troops and 435 helicopters. Aircraft were divided among three battalions: the 228th received 48 CH-47s; the 227th and 229th each received 60 UH-1D "slicks" and 12 UH-1B gunships. (5) Howze's vision had a profound effect on operations in Vietnam.

Helicopter Technology

When the United States entered the Vietnam conflict, the helicopter was a utility vehicle of marginal importance. By the end of the war, military commanders had integrated it into practically every type of mission. Significant design improvements occurred in the early 1960s that allowed operational commanders to expand the role of helicopters, which had become sophisticated war machines capable of performing diverse missions.

The armed services entered the helicopter revolution from different perspectives. The Navy was using helicopters for search-and-rescue missions and as antisubmarine warfare (ASW) platforms. The Army and Marine Corps were using helicopters largely for transporting supplies and ammunition. The Air Force was using them sparingly for personnel transport.

The intrinsic culture of the services in 1961 affected the design features of their respective helicopters. Weapons-system acquisition strategies were oriented around large-scale, conventional warfare. The Army pursued a mobile, decentralized, integrated structure that proved ideal for its tactical requirements. As a result, the Army acquired the UH-1 to replace the CH-21 in a cavalry role to support conventional mechanized units. The Marine Corps emphasized larger assault helicopters with centralized control under an air-wing commander. (6) Consequently, the Marines moved toward the larger H-34 to provide combat mobility for a self-sufficient assault force.

The workhorse for the Army until 1963 was the Piasecki H-21. The Army purchased 334 of the dual-rotor helicopters. H-21s were powered by 1,425-horsepower (hp) radial piston engines and could carry 20 soldiers. (7) In many ways, the H-21 was the test platform for the complexities of helicopter operation in a combat environment. Originally, the H-21 was unarmed and unarmored. One shortcoming of the H-21 was that it only had one small cabin door, which slowed the deployment or recovery of troops in the landing zone (LZ).