Abstract: The power and compressor units of an internal combustion rotary engine system utilize a rotor assembly, concentrically mounted on a stationary distributor core member, for rotation about an axis eccentric to the central axis of a cylindrical cavity that provides the working chamber of the unit. Three vanes are disposed in the body of the rotor assembly for slidable movement in a radial direction, which engage the cylindrical surface disposed eccentrically thereabout so as to define chambers of dynamically increasing and decreasing volume as the rotor assembly operates. The core member functions as a valve, permitting or preventing the flow of air into the compartments defined by the vanes in a sequence that is timed to establish air introduction, compression, combustion (in the power unit) and exhaust phases of the operating cycle. In certain embodiments, the surface that cooperates with the vanes may be provided by a shell that is also mounted for rotation within the engine block.