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Microcosm G-1B


I'm not 100% sure about the specification of this engine. It appears to be a uniflow design but I'd need to dismantle it to confirm that. There was no mention of this by the seller.

The brass boiler is totally enclosed in a brass wraparound firebox. It has a burner tray, which could hold either tablets or gel. The burner fumes travel through a vertical flue, through the boiler and up the chimney. The boiler is approx 50mm diameter x 80mm long. It has two water tubes underneath and also a superheater tube which passes through the burner flame, up and back down the chimney before exiting the front of the firebox to the side of the engine block. It has a safety valve on the top.

The engine block is machined from a single block of solid brass, incorporating the cylinder, crankshaft, rotary valve, regulator valve and oiler. The oiler feeds oil directly onto the valve. There are two inlet pipe fittings, one on either side of the block. One of them takes the steam feed from the superheater. I assume the other one is to drive the engine in the other direction.

The cylinder is 12mm bore x 12mm stroke. It appears to be uniflow, with the exhaust port, uncovered by the piston at the end of it's stroke, exiting through the side of the block. The crankshaft has a disk crank at one end and a heavy 40mm diameter solid brass flywheel at the other. It passes through the engine block with what appears to be a rotary steam valve inside.

Make Microcosm
Model G-1B
Made c2018
Description Marine style stationary
Cylinders 1
Cylinder Type single acting uniflow
Piston Diam mm 12
Stroke mm 12
Valve Type rotary
Boiler Type horizontal with water tubes and vertical flue
Boiler Diam mm 50
Boiler length/height mm 80
Fuel Gel or tablets
Mechanical Condition Good
Cosmetic Condition Good
Paintwork N/A
Purchased 4/6/2018
Purchase cost 64
Additional spend