Abstract: A rotary engine has a rotor shaft, a power rotor carried by and rotating conjointly with the rotor shaft, a pair of stators disposed radially outwardly of the power rotor, an annular cam ring, disposed radially outwardly of the stators, connected to and rotating conjointly with the rotor shaft, and at least one cavity formed in the power rotor that enters into fluid communication, sequentially, with an intake port, a combustion port, and an exhaust port as the engine rotates. Oscillating members that are pivotally mounted to an engine housing close the ports under the influence of cam lobes formed on the cam ring and the ports are opened by the shape of the cavity or cavities driving the oscillating members radially outwardly as the engine rotates.