The concept of the "Skycrane" helicopter emerged in the late 1950s. Sikorsky had already explored similar configurations with the S-60 and CH-37 Mojave, but the CH-54 represented a significant ...

Boeing's CH-47 Chinook, introduced to the U.S. Army in 1961 and developed to replace the Sikorsky CH-37 Mojave, is considered one of the heaviest lifting Western helicopters.