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 (HSRC) concepts. The general study guidelines were for 450-kt cruise speeds and low downwash characteristics. Each contractor reviewed potential candidate concepts and selected the most promising for this study. These concepts included 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. Systems studies at NASA Ames, supported by propulsion studies at NASA Lewis and newly initiated structures efforts at NASA Langley, are independently assessing the technology for high speed rotorcraft. 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.