A system for adjusting the pitch of a variable pitch propeller, the system comprising: a non-rotating side of the propeller; a rotating side of the propeller having a hub, a propeller blade mounted to the hub, a propeller shaft that rotates the hub and propeller blade at a propeller rotational speed, and an actuation system having a screw and an actuator element; and a motor having a non-rotating component in communication with the non-rotating side and a rotating component in communication with the actuation system, wherein when the rotating component rotates at a first speed, the pitch of the propellor is constant, and wherein when the rotating component increases speed relative to the first speed, the screw rotates and the actuator element moves laterally in a first axial direction to decrease the pitch of the propeller and, when the rotating element decreases speed relative to the first speed, the screw rotates and the actuator element moves laterally in a second axial direction to increase the pitch of the propeller; characterized in that actuator element is a hydraulically actuated piston; the actuation system is a hydraulic actuation system comprising: a hydraulic fluid source; reservoirs in the hub; a tube for transferring hydraulic fluid from the hydraulic fluid source to the reservoirs (38a, 38b), the tube having a first end and a second end, wherein the rotating component of the motor is connected near the first end of the tube and the screw is connected near the second end of the tube; and a control valve in communication with the screw and the reservoirs for controlling fluid transferred to the reservoirs; and wherein when the motor decreases speed, the screw rotates to move the control valve in the first axial direction, pressure increases in a first reservoir, and the piston moves in the second axial direction to increase the pitch of the propeller; and when the motor increases speed, the screw rotates to move the control valve in the second axial direction, pressure increases in a second reservoir to move the piston in the first axial direction to decrease the pitch of the propeller; wherein the tube is connected to the rotating component of the motor with a splined connection such that the tube rotates together with the motor. a non-rotating side of the propeller; a rotating side of the propeller having a hub, a propeller blade mounted to the hub, a propeller shaft that rotates the hub and propeller blade at a propeller rotational speed, and an actuation system having a screw and an actuator element; and a motor having a non-rotating component in communication with the non-rotating side and a rotating component in communication with the actuation system, wherein when the rotating component rotates at a first speed, the pitch of the propellor is constant, and wherein when the rotating component increases speed relative to the first speed, the screw rotates and the actuator element moves laterally in a first axial direction to decrease the pitch of the propeller and, when the rotating element decreases speed relative to the first speed, the screw rotates and the actuator element moves laterally in a second axial direction to increase the pitch of the propeller; characterized in that actuator element is a hydraulically actuated piston; the actuation system is a hydraulic actuation system comprising: a hydraulic fluid source; reservoirs in the hub; a tube for transferring hydraulic fluid from the hydraulic fluid source to the reservoirs (38a, 38b), the tube having a first end and a second end, wherein the rotating component of the motor is connected near the first end of the tube and the screw is connected near the second end of the tube; and a control valve in communication with the screw and the reservoirs for controlling fluid transferred to the reservoirs; and wherein when the motor decreases speed, the screw rotates to move the control valve in the first axial direction, pressure increases in a first reservoir, and the piston moves in the second axial direction to increase the pitch of the propeller; and when the motor increases speed, the screw rotates to move the control valve in the second axial direction, pressure increases in a second reservoir to move the piston in the first axial direction to decrease the pitch of the propeller; wherein the tube is connected to the rotating component of the motor with a splined connection such that the tube rotates together with the motor. a hydraulic fluid source; reservoirs in the hub; a tube for transferring hydraulic fluid from the hydraulic fluid source to the reservoirs (38a, 38b), the tube having a first end and a second end, wherein the rotating component of the motor is connected near the first end of the tube and the screw is connected near the second end of the tube; and a control valve in communication with the screw and the reservoirs for controlling fluid transferred to the reservoirs; and wherein when the motor decreases speed, the screw rotates to move the control valve in the first axial direction, pressure increases in a first reservoir, and the piston moves in the second axial direction to increase the pitch of the propeller; and when the motor increases speed, the screw rotates to move the control valve in the second axial direction, pressure increases in a second reservoir to move the piston in the first axial direction to decrease the pitch of the propeller; wherein the tube is connected to the rotating component of the motor with a splined connection such that the tube rotates together with the motor.