A system for adjusting the pitch of a variable pitch propeller has a hub assembly, a valve assembly, and a fluid supply assembly. The hub assembly comprises a hub rotatably driven by a propeller shaft, an actuator connected to the hub, and a plurality of propeller blades connected to the actuator with at least one mechanical connection. The valve assembly is in fluid communication with the valve assembly and the actuator. The fluid supply assembly comprises a valve control mechanism that is isolated from the valve assembly and the hub assembly. The valve control mechanism provides a variable hydraulic pressure control signal to the valve assembly, which transfers fluid to the actuator as a function of the variable hydraulic pressure control signal. Based on the fluid pressure in the actuator, the pitch of the propeller blades is adjusted.