US Patent 11746665 Bushing for variable vane in a gas turbine engine

A method of operating a variable vane for a gas turbine includes the step of locating a first bushing at least partially surrounding a first trunnion that extends from a first end of the variable vane. The first trunnion includes an outer surface that has a plurality of troughs. The first bushing includes a plurality of peaks that extend inward from an inner surface. Relative movement is produced between the first bushing and the first trunnion to form a carbon transfer film between the first bushing and the first trunnion.