COMPRESSED AIR ENGINES
Althoughof peculiar construction, the Wise rotary compressed air engine offers a very interesting design from a viewpoint of ingenuity. This engine embodies a number of novel features not hitherto employed in the construction of compressed air engines, and in view of the fact that the majority of compressed air engines are made on the principle of the opposed type, this engine suggests many possibilities for the rotary type engine.
The engine consists of five cylinders and weighs four ounces, including the propeller and mounting frame. On a pressure of 15 lbs. the engine will revolve at a speed of 1000 r.p.m. The connecting rods are fastened to the crankshaft by means of segments and are held by two rings, making it possible to remove any onepiston without disturbing the others. This is done by simply removing a nut and one ring. The crank case is made from seamless brass tubing, into which the cylinders are brazed. The valve cage and cylinder heads are also turned separately and brazed. One ring only is used in connection with the pistons. The cylinders have a bore of ¹¹⁄₃₂″, with a piston stroke of ⁷⁄₁₆″. In view of the fact that pull rods show a greater tendency to overcome centrifugal force, they are used instead of push rods to operate the valves. The crankshaft has but one post, which is uncovered in turn by each inlet pipe as the engine revolves. The “overhang” method is used to mount this engine to the model. With the exception of the valve springs, the entire engine, including the mounting frame and tank, is made of brass.