Tom Pascoe’s

70cc SLEEVE VALVE RADIAL ENGINE

Tom Pascoe is generally recognized as one of the leading designers of original model I/C engines today. Latest displayed in 2014 is this 70cc sleeve valve, seven cylinder engine to Tom’s own design, not based on any particular prototype.

This type of engine presents its own problems, especially in scale sizes, albeit quite large in this case, with power to drive a 23x8” propeller and - with further development - perhaps a 24x10” propeller in future.

The sleeves are operated in the usual way with gears driven from the crankshaft onto cranks and to ball joints on the sleeves. The sleeves are made from cast iron and have to maintain a close fit. A fan is fitted that runs at crankshaft speed to help the mixture to flow.

Lubrication is by gear pump, with a paper filter before the oil is pumped into the engine. The oil returns by gravity to the tank below.

Ignition is transistorized, incorporating a 6-volt coil and battery.

This award winning engine was photographed at the Harrogate and Sandown Park exhibitions.

Among Tom’s earlier output was a 42cc three cylinder, four-stroke radial sleeve valve engine, along the lines of the WW II Bristol engines, and a 6.5cc glow plug single cylinder sleeve valve engine.

His supercharged 25cc sleeve valve engine was shown on MEWS here.