Abstract: A powdered material hopper or container is mounted in an airplane with a downwardly facing discharge opening positioned immediately above a centrifugal material discharge wheel driven by a hydraulic motor positioned in the outer end of a pivotal support in the form of a pivotal hollow housing. The pivotal hollow housing can be pivoted between a first position in which the centrifugal material discharge wheel is adjacently facing the discharge opening of the container and a second position remote therefrom for permitting a rapid emergency dumping of all material from the container. Movement of the pivotal support means is effected by a hydraulic cylinder connected to the pivotal support means and a lug extending from the lower end of the container which also provides pivotal support for the pivotal support means.