Abstract: A surgeless combustion air blower which, due to the incorporation therein of an impeller having a novel configuration and blade shape, does not surge under periods of low turn-down, and yet which demonstrates comparable volume capacity as conventional impellers of the same diameter. The novel configuration and blade shape of the impeller inhere in three design features of the impeller: (1) the wheel bears no shroud; (2) a quadrangular inducer appends the leading edge of each blade adjacent the hub, which inducer is bent between 40.degree. and 50.degree., and preferably 45.degree., into the direction of rotation of the impeller; and (3) the blade tapers from a maximum chord immediately down-blade of the inducer to a minimum chord at its tip. In addition, the slope of the inducer-blade interface, or "bend line" of each inducer, opposes the predominant taper of the blade from which it appends.