Bohm HB22

FOREST CLASSICS

A Gas tank for the
Hornby Rocket Locomotive.
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BIX029
Boiler Pressure Regulator.
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Forest Classics, sponsors
of Robert Handcock &
Ken Edwards, at the Isle
of Man TT races.
Congratulations to Rob & Ken for winning 5th place at the 2012 Sidecar event!
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	The Bohm HB22 Vacuum Motor. (Flame Gulper.) "Smoking Gun" With an adjustable spirit burner. Technical Data: Base measurement: 200 mm x 130 mm x 160 mm Base plate material: Beech Bearings: Four high quality ball bearings. Working rpm.: 0 - 800 rpm, regulated to run slowly. Balance wheel: Diameter 70mm. Fuel: Spirit Weight: 2100g


	Bohm HB22 Vacuum Motor. (Flame Gulper.) Built model form. Price: £ 244.68p

	Bohm HB22 Vacuum Motor. (Flame Gulper.) Kit form. Price: £ 239.79p


	It can be clearly seen from the inch scale ruler, that the Bohm HB22 is much larger than the Stirling engines produced by Bohm.

Some history and technical details.
A Vacuum motor, also named flame gulper, is a hot-air motor but not a Stirling engine .The principle is quite old. In 1758 Henry Wood already was granted a patent. From the technical point of view it is an atmospheric motor, because the outer air pressure does the work (comparable to the first Ottomotor). The piston sucks the flame into the cylinder through an open valve and heat the air inside. When the piston goes back the valve closes, the air in the cylinder cools down and the outer, now higher atmospheric pressure presses the piston forward. Therefore the maximum power of the piston is limited to the product of the surface of the piston × air pressure. When the piston reaches the front dead centre, the valve opens again and the cycle starts again. A balance wheel overcomes both dead centres. Used as functioning motors for models, they are often built as stationary motors in horizontal and vertical versions and as single, double or multi-cylinders. They have been used for models of nostalgic tractors and rail vehicles very successfully.