US Patent 8066474 Variable guide vane actuator

A variable guide vane actuator for positioning the guide vanes of a turbine engine in a hypersonic missile uses compressor exhaust to drive a linked, floating piston assembly that is coupled to the guide vanes. The relatively low pressure compressor exhaust is metered by a valve to drive the piston arrangement to accurately position the guide vanes in proportion to the input control signal. Reliability and accuracy gains are achieved by inhibiting the effects of vibration and thermal distortion through the elimination of piston/bore contact, the use of a rigid, cantilevered mounting arrangement and cooling with the pre-combusted liquid fuel.