The trapezium connecting rod engine design is attributed to Professor Realeaux, who was professor of Kinematics at Charlotenburg University,  Berlin, and was taken from a Dutch textbook published in the 1890s. As can be seen the connecting rod is in the form of a trapezium and completely encompasses the cylinder. It would probably have been in the range of 5 to 25 NHP. The motion is most interesting and makes for an attractive model.

The model was originally designed by Anthony Mount in 1:12 scale and serialized in Engineering In Miniature from July 1997 to February 1998. In Anthony’s original drawings the base and brackets are aluminium castings. Gunmetal castings are used for the flywheel, cylinder, covers, steam-chest and eccentric strap. However, Julius’ design is meant to be fabricated.

The connecting rod yokes were mild steel fabrications. The valve is of the slide valve type.

To support the crankshaft there is an outrigger bearing.

Click on drawings to download.

For personal use only.

Part two here.

Although drawings reproduce well on this website, they are better as saved downloads.

As usual with Julius’ designs it can be constructed without castings.

Please let the editor know if you are building one of these or other projects to Julius’ drawings.