Abstract: A novel rotary prime mover is provided having a generally cylindrical casing including an axial air intake, an axial exhaust outlet and bearing means at each circular end thereof to support a longitudinally arranged shaft. A flywheel block is rotatably mounted within the casing on the longitudinally arranged shaft and is arranged intermediate the air inlet and the exhaust outlet. The longitudinal shaft has a fuel inlet passage concentrically bored therethrough. The flywheel block includes at least two balanced diametrically opposed jet reaction engines recessed and secured in a specifically recited manner at the circumferential edge thereof.