Abstract: The invention describes a mechanism to cause an actuator born on a rotating shaft to modulate backwards and forwards independently of the motion of the rotating shaft. This mechanism is then used to realize a controllable-pitch blade fan. The axial modulating mechanism is achieved by mounting a thread on the rotating shaft onto which an axial modulator, with a cylindrical cavity having a mating thread, is mounted; magnets induce the axial modulator to rotate independently of the shaft's rotation in turn causing the axial modulator to move linearly along the shaft. This mechanism's linear motion is then used to force blades rotatably mounted on the shaft to rotate and consequently vary their pitch.