Julius de Waal

H. Muncaster’s little book on Model Stationary Engines - Their Design and Construction was first published in 1912, and revived in modern times by TEE Publishing. Muncaster wrote:  “To those of a mechanical turn of mind, nothing has, perhaps, in the whole range of useful inventions, proved a source of more sustained interest than the steam engine. As with many other of the now indispensable contrivances, the steam engine was at first looked on as a toy or an interesting experiment. The extent of its great utility and benefit to mankind could hardly have been dreamt of even in the imagination of the most earnest of its enthusiastic pioneers.

“It is a small wonder, then, that it has provoked so much attention in old and young, and a desire in so many minds to copy and reproduce for pleasure and study.

“Amongst the first to make the steam - engine serviceable were Papin, Savory and Newcomen; Humphrey Potter, who as a boy originated the automatic working of the valves; James Watt, the inventor of the separate condenser; Trevethick, Hedley and Hackworth, the pioneers of the Locomotive. After which came a host of workers applying the steam engine to almost every conceivable purpose, perfecting the details and improving its efficiency and economy.

“For the purposes of the model maker, however, it does not follow that the most recent and perfect engines are most suitable; on the contrary, some of the older engines form subjects better adapted and more fitted as prototypes for models, being more picturesque and providing better object lessons.”

Muncaster goes on to describe a whole range of model engines from the simple oscillator to the compound engine with, in-between, several slide valve engines, marine engines, vertical and horizontal engines, and so on. In accordance with his philosophy, every one is most attractive. Many can be seen at shows today, often to ET Westbury’s re-worked drawings from the 1950s.

Julius has prepared working drawings for all these engines and will appear on MEWS in the coming weeks. This is Muncaster’s two-cylinder compound vertical steam engine.

E. T. Westbury described this engine as a type well suited to model marine work, its size suitable for fairly powerful prototype boats such as tugs, pinnaces or fast packet liners up to 6ft or more in length. This form of assembly calls for careful location of the pillars, both at the bedplate end and in the cylinder base flange. It also calls for accurate lining up of the slide bars, so that they are exactly parallel with the cylinder axis, both crosswise and sideways.

“The steam chest arrangement of this engine is very ingenious in design, as it allows of a  single chest for both h.p. and l.p. cylinders-rather unusual in compound engines-thus eliminating the need for an eduction pipe which...  may be a source of heat wastage, especially as it often extends the full length of the cylinder block. This improvement is effected by using an inside-admission piston valve for the h.p. cylinder and a flat, slide valve for the l.p. cylinder. Entry to the piston-valve housing is by way of a port in the side of the cylinder casting between the ‘lands’ of the valve and exhaust escapes at the ends of the valve, directly into the main steam chest space, whence it is admitted to the l.p. cylinder under the control of the flat slide valve. It is finally exhausted by way of  the cavity in this valve, in the normal manner.”