Abstract: A rotary energy converter has a rotor provided with a plurality of hinged vanes and centrally mounted within a stator having a generally circular inner wall surface formed with one or more vaulted bays and corresponding abutments. As the rotor rotates within the stator, the hinged vanes are urged outwardly by centrifugal force into wiping contact with the stator inner wall, and are alternately extended and retracted, as the vanes encounter the vaulted bays and abutments to provide a respiring chamber between each pair of adjacent vanes. In one preferred form, the energy converter is shown as a rotary internal combustion engine having at least two vaulted bays, one of which constitutes a fuel inlet and compression bay, and the other of which constitutes a combustion expansion bay with an ignition station located between said bays.