My 1/2 scale model of Roy Ozouf's grasshopper crosshead engine. 7/16 bore x 3/4 stroke. All dim. were held, just changed some looks to suit my own tastes. Very good runner on 3# of air.
Mike http://www.youtube.com/watch?v=Q7NvGg6cfMQ&feature=youtu.be
Mike http://www.youtube.com/watch?v=Q7NvGg6cfMQ&feature=youtu.be