The crank case is constructed from four pieces of 24 gauge spring brass, substantially connected in the form of a rectangle, the top and bottom being left open. The front and rear walls have flanges which engage the inside of the side walls and are secured thereto by four small screws on each side, thereby making it an easy matter to take the crank case apart.
The four cylinders are made from drawn brass shells and have a bore of ¹⁄₂″ and stroke of ¹⁄₂″. The pistons are made of solid red fiber. The two-throw crankshaft is built up of steel with brass webs. The bearings are of steel. The valves, being overhead, are driven by a gear mounted at the end of the crankshaft, the gear driving the valve shaft by means of a gear on that shaft, with which the crankshaft gear meshes. The valve arrangement, as shown indiagram 18, consists of four recesses cut into the valve shaft, two of which allow the air to pass from the inlet pipes, which lead into the valve chamber at the center of same, to two of the cylinders at once, while the other two recesses allow the exhaust to pass from openings in the sides of the valve chamber.
The cylinders are secured to the side platesof the crank case so that when those side plates are removed, the cylinders are removed with them. The pipes are detachable at their centers; small pipes running to the heads of the cylinders extending into the larger pipes which run to the valve chamber. This arrangement is shown in the end view of the engine. A 17″ propeller is used in connection with this engine.