Published online by Cambridge University Press: 04 July 2016
After many years of helicopter design, development, and operations, a practical flying crane helicopter is under construction whose particular features promise an unprecedented utility. The steps leading to this new helicopter configuration were evolutionary in nature dating back as far as 1922 when the deBothezat quadrotor machine hovered for one minute and forty-two seconds.
Early military interests in improved mobility of the armed forces and the experiences gained with helicopters in the Korean War gave impetus to the development of vertical lift capability. In addition to the basic helicopter developments specific crane flying test beds and parametric studies were sponsored by the military. These projects included the Hughes XH-17 flying crane, the McDonnell XHCH-1 rotor test programme and the Sikorsky HR2S-1 (H-37) helicopters. In addition design study contracts were sponsored which determined the feasibility of constructing crane-type helicopters of 8 to 16 ton payload capability.