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.