High speed rotorcraft - Comparison of leading concepts and technology needs

Design studies have recently been completed by Bell, Boeing, McDonnell Douglas and Sikorsky with the goal of identifying technology needs of high speed rotorcraft concepts. The general study guidelines were for 450-kt cruise speeds and low downwash characteristics. These concepts included the the folding tiltrotor, the high speed tiltrotor, the variable diameter tiltrotor, a tip-drive stopped rotor and the tilt wing. The studies have also identified technology needs of these concepts with the objective of defining a systematic program of technology development to increase confidence in the subsystems and components and achieving a low-risk design capability in the year 2000. Each contractor has reported independently on his efforts. This paper is a survey of the contractor efforts taken together, with regard to concepts, selection methods, technical issues (common and critical technologies), technology benefits and the technology plan recommendations.