Abstract: An airfoil having a suction surface and a pressure surface, the surfaces joined together at leading and trailing portions of the airfoil, the pressure surface converging toward the suction surface at a corner, the surface converging at the corner by an angle approximately equal to or greater than at least 30.degree., such that an air stream flowing from the leading edge and over the pressure surface separates from the pressure surface at the corner. The fan therefore has a thick nose section and is substantially thinner over the majority of its chord length. One or more guide ribs extend from the pressure surface to control the flow of boundary layer air.

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 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 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.

Abstract: A low noise, axial flow fan particularly suited for use in a turbulent air flow such as the flow exiting an automobile radiator has a band that is secured to the outer ends of the fan blades. The blades are highly forwardly skewed and have an increasing blade angle as a function of blade radius over at least the outer portions of the blade. Each blade is secured to the band along its full width. In the preferred form, the band has a cross-sectional shape that acts as a nozzle to accelerate the airflow through the fan, each blade has a cambered, airfoil cross-section, and the entire fan is formed of an injection molded plastic as a single, integral structure.