Many  were  impressed with a twin-cylinder steam engine at the National Model Engineering and Modelling Exhibition at Harrogate in 2011. That engine was made from stock materials (no castings) by Brian Stephenson, and since by readers of MEWS. It is one of the engines Brian has built to designs by Bob Middleton. Bob allows his drawings to be put on MEWS. But he asks readers to bear in mind, that they were drawn for personal use rather than being published. He also points out that he has no formal training in design or engineering, and begs forgiveness for departures from standard practice. Bob actually started designing engines to while away the time on long sea voyages when he was captain on oil tankers. This week we have the first half of the drawings of Bob’s latest design a Scotch Yoke Engine (photo of his own model above). The drawings include some explanatory notes to help in making the components. All of these drawings can be downloaded for personal use.

The Scotch yoke is fascinating to watch as the animation shows.

Click on drawings to download.

Bob’s other engines here and here.

Part two here




By Bob Middleton