Abstract: A winnowing blower for discharging a stream of air over the sieve of a combine harvester-thresher has an axially elongated housing formed at each of its axial ends with an inlet opening provided with an axial-flow fan. A shaft passing axially through the housing carries these two fans and two deflector disks spaced inwardly from the fans and each of a diameter substantially less than the respective fan. The housing is provided with a radially extending plenum chamber so that air drawn axially into the ends of the housing is partially deflected by these plates and ejected outwardly through the plenum chamber over the sieve of the combine.