The Martin Baylis double acting piston valve twin engine has been designed to replicate as much as is practical at this scale the appearance of a compound engine. Great attention has been paid to represent the materials that would have been in use at the time; predominantly cast iron, brass, bronze and steel.
Items such as connecting rods and eccentric rods are fully machined and profiled giving the appearance of the original items. In the case of the eccentric rods, stainless steel and brass have been used to simulate the bronze eccentric strap and steel eccentric rod of full sized practice. Effort has also been made to keep the engine “tidy” with the displacement lubricator being tucked neatly in at the side of the throttle assembly. Other features include; many by popular demand are a low sitting crankshaft much in keeping with the original practice of the day, a more authentic compound appearance with cylinder heads and steam chests of dissimilar sizes. For convenience of the modeller the engine is of single servo operation all throttle, forward and reverse functions on one lever.
The trademark simulated wooden cladding complete with brass straps adds to the look of authenticity, as do the cylinder head fixings which are especially made to replicate dome head bolts. Connecting rods display bolt heads at the big ends. Reversing and throttle leavers have been designed to look in keeping with the controls of a real engine. Crank shaft webs are profiled to give the appearance of counterbalanced webs. This attention to detail in addition to the overall construction and aesthetic of the engine is designed to be pleasing to the eye
Working Pressure: 30-45psi (2-3 bar)
Length: 75mm or 3″ (excluding throttle handle)
Width: 45mm or 1.77″ (excluding throttle handle)
Height: 84mm or 3.3″ (excluding lubricator cap)
Weight: 322g or 11.35oz
This engine has been engineered to give a balance between the aesthetic appearance and sound engineering practice. Miniature roller races have been utilised extensively the crankshaft and big ends are supported on roller races. The result is that the bottom end of the engine requires very little lubrication other than minimal lubrication for the eccentric straps. This lends itself very clean and smooth operation together with low maintenance.
In an effort to simulate materials of the age, the block, steam chest and engine bed have been manufactured from aluminium which is then treated to give a textured finish. The components are subsequently hard anodised to BS5599. Hard anodising has a hardness approximating “sapphire” and is therefore very durable and wear-resistant. This combination gives a finish that closely resembles that of cast iron. Pistons and slide valves are manufactured from complementary materials which offer extremely good sealing characteristics combined with very low friction.
Stainless steel, brass and bronze are used extensively throughout the engine. As a result of this, the engine is lightweight, compact and powerful, offering the modeller an engine that looks authentic and is highly functional which should give years of untroubled enjoyment.
These two pictures show the fully profiled appearance of the crank webs together with the economical nature of the engine bed. The dissimilar size of the cylinder heads and steam chests can also be seen.