Abstract: A line of forwardly curved blower wheels of different diameters incorporates blades of the same angular extent in all wheels but with the radii of curvature of the individual blades proportional to the diameter of the wheel wherein they are incorporated. In addition, the center disks of the double inlet wheels and the end plates of the single inlet wheels are provided with novel mounting structure comprising segments bent out of the plane of the disk or end plate and secured to opposite ends of the hub member by which the wheel is mounted on a shaft, and the individual blades are retained in complementary slots in the disk or plate and fillet welded to the disk or plate respectively.