METHOD FOR CONTROLLING A ROTOR-CRAFT FLIGHT DURING TRIM

摘要

A method for controlling a rotor-craft flight during trim without directmeasuringrotor flapping is provided. The method includes: a) providing a predeterminedtargetflapping trim state, b) determining a collective control stick position, c)determining air speedof the rotor-craft, using a), b), and c) to determine a desired longitudinalcyclic stick positionfor trimmed flight, and e) moving a control surface of the rotor-craft tochange a rotor-craftpitching moment until an error between an actual longitudinal cyclic stickposition and thedesired longitudinal cyclic stick position of a cyclic control stick issubstantially zero. Themethod allows the rotor-craft to be automatically trimmed towards a desiredtrimposition. For example, the rotor flapping of a rotor-craft can beautomatically trimmedtowards the forward flapping endurance limit so as to decrease damaging yokeloads duringpull-up maneuvers and thus increase overall yoke life.