Single Rotor Options for Heavy Lift and Potential of Multi Lift

After 30 years of continual rotor-craft payload capacity growth, there are strong indications that this trend is leveling off. First, this paper reviews the current state-of-the-art to show that the root of the problem is not any unsurmountable technical barrier and briefly discusses the single rotor options for heavier lift as illustrated by growth derivatives of the CH-53E as well as by the Sikorsky response to the Army HLH proposal. Secondly, it examines the economic factors which appear to have militated, up to this point, against development of larger helicopters for either civil or military requirements.

Finally, the paper considers the opportunities to solve the problem of occasional requirements for very heavy lift of single piece payloads by the harnessing of two or more helicopters to a single load - the so called multi-lift concept. The history of Sikorsky studies and flight feasibility demonstrations are reviewed, and the opportunities for applying advanced control technology to offset the pilot workload problems identified in these demonstrations are discussed.