Model Twin Cylinder Engine.

Progress, Volume IV, Issue 1, 2 November 1908, Page 16

Model Twin Cylinder Engine.

Tlie design of tliis engine is the original idea of the maker, Mr. Gr. U. Judkins, of Christchurch. It is of the marine type having all the working parts enclosed in a chamber. This model is entirely built of castings, and is about the first engine made by the designer. It is all the more worthy of note as it is ihe first attempi at a slide-valve engine, its predecessors being oscillating engines made of '-crap brass and solder. This engine gained a prize at the New Zealand Exhibition and a cash prize donated by Messrs. Baldwin and Hay ward, patent agents. A few of the details of the engine will help the reader to understand more clearly the working of the model. Fig. 1 gives a front view, and Fig. 2 a side view. The two cyhndeis aie of cast iron airanged side by side on top of an aluminium ci.uik chambei. They are l£in. bore h} JJiu. stroke. The pistons aie of cast iion, with t^o i>ioo\es for lings. They aie tumk pistons, having the piston rod fastened by means of a gudgeon pin. The piston rods aie fitted with gun nusal biasses, which mil very smooth in conjunction -«ith the mild "steel <iank fhafL The steam chest is of cast iiou with polished^ gun metal covers. The (rank diambei is of aluminium with a gun metal bush at either end, making a good beaimg for the shaft. This clnunber is

fitted w ltli an ovei-flow pipe at eacli end, which allows the waste oi] <uid water to escape. The lubrication of tlie engine piesents no diffk ult\ , as tin's oluuulkm is kept a (|il.utei full of <>-ood oil. r l') lr ciank ,spla,slmii> into this tilling the oil to all working paits Tlieio is ,ilso it middle section oi the top cliainbei cut out,

which enables the engineer to see the workings. A polished brass plate covers the opening- when not in use. The chamber is screwed together with sis polished brass standards, which also support the engine. The laces of the libs and ends are polished, giving a good effect to the engine. The two fly wheels give a steademotion, but under heavy driving two much

heavier wheels are used, and there is also a large pulley wheel, not shown in the photo. The steam pipe is solid drawn copper pipe, gin., and the exhaust thin drawn brass pipe, -gin. The pipe fittings are of polished brass. The engine is about I h.p., i mining at 1000 rev. per mm., oOlh. steam pressure, and lias been tested under the above conditions and found efficient.