Analysis Of High Flight Speeds On Compound Rotorcraft Design

Abstract

Capabilities for new medium-sized utility rotorcraft with enhanced flight speeds have been investigated in recent years by numerous research studies. An opportunity for realization of such a configuration may come with the NATO project NGRC, which is considering a desired flight speed of up to 220 kn and not less than 180 kn. DLR supported these investigations with a high-speed rotorcraft design study. The objective was an increase of flight speed by 50% to about 240 kn, which resulted in tremendous amount of required power. The configuration was considered to be very performant, but inefficient with respect to the conventional flight envelope. In this paper, the required speed interval for project NGRC is investigated. The design space is defined by four design speeds besides of three required flight distances. The baseline configuration is a revised high-speed rotorcraft from the first study, featuring a new main rotor. The twelve design configurations are analyzed considering their characteristics like installed power and flight performance. The increase in size and weight is continuous with increasing speed and range. Recommendations for the further progress are defined based on the results of the design study.