Abstract: A rotary internal combustion engine comprising an elongated rotor having an oval shaped cross-section secured to a compartmentalized shaft rotatably disposed in an elongated cylindrical shaped bore in a stationary engine block. A plurality of vanes, having a curved wedge-shaped cross-section, are pivotally secured to the block and arranged to move into the cylindrical shaped bore into sealing engagement with the outer surface of the rotor. Fuel and air are delivered through the compartmentalized shaft into chambers between adjacent vanes where fuel is compressed, ignited, and allowed to expand applying torque to the oval shaped rotor. The oval shaped cross-section of the rotor has long sides which are substantially straight and first and second arcuate ends.