This model nine-cylinder radial engine has one-inch diameter cylinders and valves the size of screw heads. And almost every piece of it was hand machined. My brain aches when I think about the amount of patience required to carve the tiny parts out of hunks of aluminum and steel. The engine was designed by Lee Hodgson of Cincinnati, OH, and made by John Collier. If you possess the singleminded determination and machining skills to build one, plans and some parts are available at Agelessengines.com. In addition to the nine-cylinder model, there are 14 and 18-cylinder mills. All the engines I’ve seen are stationary. But that shouldn’t stop you from putting one in a remote-controlled biplane. Or a minibike.