Hi All A while ago I came across an engine on Google which I had not seen before named a Denny improved hot air engine, I could see straight away that the working geometry was similar to that of the Rider-Ericsson engines that we often see, but that the mechanical configuration differed in that the flywheel was central of the engine as opposed to one side on the RE and the beam was yoke type to accommodate the flywheel. There was only a picture on Google but as I have built a couple of RE engines I felt this was enough to have a go. This model is scratch build from plate and bar stock the most detailed part being the water jacket that houses the cylinder that is made from a block of Al. Alloy. It is only 1 inch bore which I chose having previously made a lap that size and the flywheel is made up more like the old wooden wheels with a central hub with the spokes set in and passing through the outer rim. It was not a difficult engine to build but like all small stirling engines care must be taken when lapping the piston to the cylinder to try to achieve the impossible situation of zero clearance with zero friction, also as there are quit a number of links and pivots there is plenty to bind up, but happily it started up straight away and runs quite happily on a small spirit lamp. I will try and post you a couple or pictures. Hugh.