Centrifugal fan wheel with changeable pitch blades

A centrifugal fan wheel is provided with blades 10 which may have their pitch changed through circumferential movement of a ring 30 tied to an outer tube 28 encompassing a drive shaft 24 and capable of having its rotative position relative thereto changed, through the axial movement of a control rod 38 to which is attached a pin 44 extending into the control rod through a diagonal slot 42 in the outer tube and an axial slot 40 in the drive shaft. In a further embodiment an inlet vane 50 has its angle changed through its pivotal relation that one edge of the vane with a slot 60 in the outer tube, so that both blade 10 pitch and vane 50 angle are concurrently changeable.