Passively Varying Pitch Propeller for Small UAS

Abstract

A novel design for a passively-varying pitch propeller to improve small UAS performance is examined. The proposed system uses propeller blades free to pivot on a radial axis and blade cross sections tailored fo r positive pitching moment to achieve stable and efficient operation over a large advance ratio range. Computational analysis of the passively-varying propeller system indicates that large improvements can be gained, especially at high advance ratios, while sacrificing very lit tle low speed performance. A properly designed propeller will enable a much expanded flight envelope and, with proper limits to rotation angle, good takeoff/ climb performance and automatic feathering in the engine off case. Experimental analysis to corroborate computational findings is currently underway.