Stoking the steam, one engine at a time…
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Type S

Type: Vertical, single cylinder, double acting, slide or piston valve.
Height: 22 in
Weight: 120 Lbs
Flywheel: 10 in
HP: 1 1/4 HP
Watts: 800-1000 W @1000 r.p.m.
Availability 1934-1962.


In 1934 Stuart designed this small general purpose steam engine for industrial use. A lot of factories were still equipped with steam for various uses even though full steam mechanisation had faded. Originally paired with a generating set it was capable of 800-1000 watts. It was also used for a range of functions including running ventilation fans. The single cylinder engine was available in several versions including both slide valve and piston valve types. Fitted with an integral oil pump it was capable of continuous running. Also fitted was an adjustable governor, allowing its speed to be regulated to match whatever purpose it used for. I have been unable to find anymore info as I cannot find it appearing in any OF Stuart’s catalogues.

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Early Type S

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Early Type S. The protuberance from the cylinder appears to be the Piston type valve. Note the mechanism at the left, it appears to be the governor, varying the steam admittance based on engine speed.

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Closeup of the cylinder and external piston valve.

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A later model, Type S/GL.

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Notice the box on the right which appears to be a resevoir for the oil system.

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This is also a piston valve but appears to be a more sophisticated design.

Video Of Stuart Type S Running

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