Classic Four

FOREST CLASSICS

A Gas tank for the
Hornby Rocket Locomotive.
Click here for details.

BIX029
Boiler Pressure Regulator.
Click here for details

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!
Visit RJ Road Racing website
Click here

The Classic Four Gas Engine.

The “CLASSIC FOUR” 4 cylinder axially mounted piston motor with “tumbling spider” has its basis in aircraft engines tested in the 1930's & 1940's.

The Piezo ignition system is built into the base, and is driven with a toothed belt and a central distributor by the engine. The gas and speed regulation are controlled by a valve on the gas tank with pressure indication.

Ball joints connect the tumbling spider and piston.

The elegant motion of the four-cylinder is particularly emphasized by the open build method.

Parts moving in opposite directions, the tumbling spider, piston, crosshead and valve rods, result in an interesting mechanical interaction.

Technical data:

Speed regulation:	Valve at the gas tank
Tumbling spider:	Quadruple, running in ball bearings.
Capacity:	1½ cubic centimetres x 4
Number of revolutions:	approx. 200 - 1000 rpm
Height:	240 mm
Width:	180 mm
Length:	280 mm
Weight:	3.2 kg - with tank and base plate.
Running time:	Approx. 10 min on one gas filling.
Flywheel diameter:	Approx. 123 mm
Ignition:	High voltage Piezo crystal.