Heinrici Hot Air Engine

This is a 1/4 scale Heinrici Hot Air Engine. The engine stands about 21" tall with a bore of  1-1/2" diameter & 2" stroke.  The castings were purchased from Norbert Keeley Model Engine works. The current distributer is Myers Model Engine Works. 15929 Five Point Road. Perrysburg, Ohio 43551. (e-mail myersmodel@aol.com(419) 878-6051 (They also have many other casting kits.)   I received an advertisement for this engine at the time when I purchased the Ericsson castings. This engine runs but not as steady or easily as the ericsson. Don't know if this is a design problem or a builder problem. Probably the latter. This engine runs on propane gas.