Abstract: A compact, efficient axial flow fan with blades that are rearwardly (i.e., away from the direction of fan rotation) skewed and which are oriented at a pitch ratio which continuously decreases as a function of increasing blade radius along the radially outermost 30% of the blade.

Abstract: A fan in which the root-to-tip net blade skew angle (A.sub.b) (either forward or rearward) is less than 1/2 of the blade spacing; in a first radially inward region of the blade, the blade is rearwardly skewed as indicated by the leading edge skew angle (A.sub.e); in a second region radially outward of the first region, the leading edge skew angle indicates a forward skew.

Abstract: A circumferentially banded fan that forces air through an adjacent heat exchanger and that has an air-guide housing positioned radially outside the band and extending downstream therefrom is disclosed. A plurality of elongated stationary members extend radially inwardly from the housing downstream from the fan blades, and the stationary members have a flow-control surface which removes the rotational component imparted to the airflow by the rotating fan blades. A tangent to the flow control surfaces at their radial center line forms an angle with the airflow exiting the blades which is substantially equal to the tangent-to-axis angle.