Before the unfortunate demise of RAH-66 Comanche, there was AH-56 Cheyenne, and the latter was the epitome of “in the wrong place at the wrong time,” as the aircraft’s rigid-rotor design concept was obviously way ahead of its time.

Dawn of Close Air Support

It was the mid-1960s, and Lockheed had just presented a novelty aircraft concept to the U.S. Army under the Advanced Aerial Fire Support System (AAFSS) program that would eventually become the service’s first dedicated attack helicopter.

According to Bob Mitchell, curator of the Army Aviation Museum, the AH-56 Cheyenne featured designs from “the rigid rotor system,” which was present in Lockheed’s previous aircraft—the CL-475 (1959) and the XH-51 (1962). The manufacturing company equipped the AH-56 Cheyenne with a four-bladed rotor system, subsequently configuring it into a compound helicopter with low-mounted wings and a tail-mounted thrusting propeller powered by a General Electric T64 turboshaft engine. Consequently, the aircraft was mapped out to have a high-speed capability so it could catch up and provide escort for the Army’s utility helicopters.

The design was approved, and by 1966, Lockheed received a contract detailing to supply ten prototypes of the futuristic AH-56 Cheyenne to the U.S. Army. By mid-1967, the company began its first official flight test using the second AH-56 (s/n 66-8827). However, engineers uncovered issues on the earliest prototype and decided against proceeding to flight testing to resolve those problems.

“It’s an enormous aircraft and it was capable of great speeds—that was one of the main reasons (the Army) wanted the program,” said Mitchell. “(The Cheyenne) had a set of aerodynamic wings on it, so the faster the aircraft went, the more the rotor loads were reduced.”