The Wallaby - E T Westbury
Following the successful launch of the diesel powered Aveling & Porter Road Roller in 1938, Westbury turned his attention to developing an IC powered model locomotive. In 1941 the 3½" gauge 1831 LMS Shunting Locomotive was released. As one would expect, the design was highly innovative and performance was exceptional. As Westbury anticipated however, locomotive enthusiast (then as now) would not easily abandon steam! The powerful engine developed for this project however was adapted to suit many application, including both marine and stationary installations. In 1962 a "Mk2" version of this much renowned engine was created and dubbed The Wallaby.
Those in-the-know site the Wallaby as an example of a truly refined and durable power plant. Westbury, a master of understatement simply noted that it was "an engine capable of packing a good punch for its size, yet docile and flexible withal, and not too difficult to construct". With a bore x stroke of Ø1" x 1 1/8", the 360º vertical twin provides a useful 29.0cc of swept displacement. Heavy split main bearings ensure a rigid bottom end and the camshaft, driven by broad timing gears, operates overhead valve gear via push rods. Unusually, the valves are arranged so that the inlet ports are central and the outlet ports outboard, facing fore and aft. The carburettor, complete with float chamber is borrowed from the Kiwi Mk2 and provides a good level of control with mechanical mixture compensation.
Overall dimensions for the finished engine are: 7" tall x 6" long x 3 5/8" wide. A magnificent project!
The Wallaby in Action