Despite its cancellation, the Lockheed Martin AH-56 Cheyenne left a lasting legacy on US military aviation.
In the 1960s, as the Vietnam War was raging, Lockheed Martin created a concept known as the AH-56 Cheyenne attack helicopter as part of their attempt to win the United States Army’s Advanced Aerial Fire Support System (AAFSS) contract. The Cheyenne was envisioned as a high-speed, heavily armed platform that could provide close-air support (CAS) as well as anti-armor capabilities.
Despite its technological advancements, however, the Cheyenne never went into full production—becoming a case study, and an unheeded warning, about the challenges of military procurement, technological overreach, and shifting strategic priorities.
The Cheyenne Helicopter’s Unlikely History
The Vietnam War had exposed the limitations of existing American helicopters, such as the Bell UH-1 Iroquois (or “Huey”), which lacked the speed, firepower, and survivability needed for the battlespace in which the Army was fighting. In 1964, the Army launched the AAFSS program, seeking a helicopter that could combine the roles of gunship, escort, and reconnaissance platform.
Lockheed, a firm that was better known for its fixed-wing aircraft, won the contract in 1966—beating out more conventional competitors Bell and Sikorsky.
Lockheed’s design was radical for its time. The Cheyenne was not a traditional helicopter, but a compound helicopter; it incorporated a rigid rotor system, a pusher propeller, and small wings to enhance its speed and maneuverability. The goal was to create a platform that could cruise at speeds exceeding 230 miles per hour, far surpassing the capabilities of contemporary helicopters like the Huey and the AH-1 Cobra. The Army ordered ten prototypes in 1967, and the first Cheyenne flew on September 21, 1967, marking the beginning of an intensive testing phase.
A technological marvel for its time, packed with innovative features that set it apart from its peers, the AH-56 Cheyenne’s compound design was central to its high performance. The Cheyenne’s new rigid rotor system allowed for greater agility and stability, enabling it to perform aerobatic maneuvers like dives and steep climbs. A rear-mounted pusher propeller, powered by a General Electric T64-GE-16 turboshaft engine, provided additional thrust, pushing the helicopter to high speeds. Small stub wings offloaded lift from the rotor when traveling at those high speeds, improving efficiency and reducing stress on the rotor system.
The Cheyenne’s armament was equally impressive. It featured a flexible weapons suite, including a nose-mounted 30mm XM140 cannon or a 7.62mm minigun, and a belly turret with a 40mm grenade launcher or another minigun. The helicopter could also carry up to 2,000 pounds of external ordnance, including TOW anti-tank missiles, 2.75-inch rockets, and infrared-guided missiles, making it a versatile platform for engaging both ground and air targets. Its advanced fire-control system, which included a helmet-mounted sight, allowed the gunner to aim weapons by turning their head—a precursor to modern targeting systems.
For the 1960s, the Cheyenne’s avionics were state of the art. Not only did it have an integrated fire-control system, but the bird possessed a Doppler radar along with a night vision system, enabling all-weather and low-flight operations. The cockpit was designed for a two-man crew—a pilot and a gunner—with advanced displays and controls that reduced the workload during combat. Its armor and redundant systems enhanced survivability, while its composite materials and streamlined fuselage reduced weight and radar signature.
Despite its promise, the Cheyenne faced significant challenges during development. The compound helicopter design, while innovative, introduced complexity that led to technical issues. The rigid rotor system was prone to instability at high speeds, and early prototypes experienced dangerous oscillations.
In March 1969, a fatal crash of a Cheyenne prototype during testing highlighted these problems—forcing Lockheed to implement costly redesigns. The pusher propeller and wing configuration required precise integration, adding to development delays.
Political Headwinds Killed the Cheyenne
Beyond technical issues, the Cheyenne faced political and strategic headwinds. The US Air Force, protective of its CAS role, viewed the heavily armed Cheyenne as encroaching on its territory, leading to inter-service rivalry. Meanwhile, the Army began to question the program’s cost-effectiveness, especially as the simpler and cheaper Bell AH-1 Cobra was already proving effective in Vietnam. The Cobra, while less advanced, was available immediately and met many of the Army’s immediate needs, reducing the urgency—and hence the budget—of the Cheyenne.
By 1972, the Army had canceled the AH-56 Cheyenne and the overall AAFSS program that supported it. The Cheyenne’s intended role was partially filled by the AH-1 Cobra, and the Army later launched the Advanced Attack Helicopter (AAH) program, resulting in the iconic Boeing AH-64 Apache.
Despite its cancellation, the Lockheed Martin AH-56 Cheyenne left a lasting legacy on US military aviation. Many of its technologies, notably its helmet-mounted sight and advanced fire-control systems, became standard in later helicopters like the Apache and Boeing-Sikorsky RAH-66 Comanche (which, ironically, was later canceled as well). It was a helicopter ahead of its time—and equally no longer needed. Yet it continues to have influence today.
About the Author: Brandon J. Weichert
Brandon J. Weichert, a Senior National Security Editor at The National Interest as well as a contributor at Popular Mechanics, who consults regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including the Washington Times, National Review, The American Spectator, MSN, the Asia Times, and countless others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
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