Abstract: An axial fan has a blade support wheel coupled to a drive shaft. A disk is positioned about the drive shaft adjacent the wheel. A torsion spring is coupled to the wheel and to the disk. When the torsion spring is in tension, the disk is poised for a relative rotation about the drive shaft. A lock couples the disk to the wheel when the torsion spring is in tension. Fan blades are supported by the wheel, and are coupled to the disk. Rotation of the drive shaft rotates the fan blades generating a specific flow direction. To reverse the flow direction, a release mechanism uncouples the lock from the disk and wheel causing the disk to experience rotation about the drive shaft as tension in the torsion spring is released. The disk's relative rotation re-positions the fan blades reversing the flow direction as the drive shaft continues to rotate.