'Above left: Base, flywheel, cylinder and head castings. '
Last summer I found a truly unique model engine kit designed by Nick Rowland (http://rowland.20megsfree.com). It is an internal combustion atmospheric engine. I was apprehensive about this project at first, because I have never done such an extensive machining project. I'm no machining expert; I have only a little experience, especially with a milling machine. The kit comes with four castings, nameplate and complete instructions for building and start-up. I made all of the remaining parts (including nuts, springs and tubing), except for the bolts, governor drive belt and the drain valve at the rear.
The engine is fairly small, 7/8-by-1-2/5-inch bore and stroke, 10-1/2 inches long, 5-1/2 inches wide and 6-1/2 inches high. I learned a lot about what I can actually make in my shop.
Some parts are very small, like the intake valve with a 1/16-inch diameter stem, over 1 inch long, made without tapering. I added a few embellishments to it. I thought an engine this nice deserved a flyball governor. I designed it after the Hornsby Akroyd design. (I like that particular one.) It spins and flies out, but does not control the engine. Experiments showed that it just cut the engine out. I made two of them: The first one I thought was too big for this engine, so I scaled it down 25 percent. It looked better. (Not bad for cutting spheres freehand!) The engine took about 250 hours to make, including the parts I had to make over and de-bugging.
One neat thing about this engine is that it has no gaskets, except for some sealant on the carburetor parts. Yet it still has perfect compression! I found it a very rewarding project to work on and I got a very neat little engine out of it! I would like to thank Nick for coming up with such a nice engine and for his patience in answering my many questions.
Contact David Cox at: 9 Masefield Circle, London, ONT Canada N5V 1M9.