Performance metrics for tiltrotor flight dynamics during the transition regime

Abstract

For control system design purposes, desirable locations of short period and phugoid poles with their respective damping factors and natural frequencies are specified for fixed-wing aircraft in U.S. Department of Defense military specifications (MIL-SPEC) documents [1,2] and for heliocopters in aeronautical design standard (ADS)/MIL-SPEC documents [3-5]. In both cases, the control system designers can verify and demonstrate the validity of their design, in part by analytically verifying that the closed-loop system, when linearized about different trim conditions, possesses damping factors and natural frequencies that satisfy these requirements.