Above: right side view
Below: left side view



Cylinders: 1
Type: Vertical Hit & Miss
Bore: 1.062”
Stroke: 1.362
Displacement: 1.20 cu. in.
Compression Ratio: 6:1
Ignition: originally coil/spark plug; later glow plug
Cooling: air
Fuel: 15% nitromethane/methanol mix
Max. RPM: 6,500 (3,500 governed)
Est. Horsepower: 0.45


Background -- After building my first Hit & Miss engine from a kit I became more intrigued by this old type engine, originally built by the Perkins Co. The result is this vertical Hit & Miss engine with a flyball governor.

Construction -- I sent for drawings for a quarter scale model of this engine, but after looking them over decided I would make my own design. For one thing, the quarter scale made a model that was too large for my taste. I also didn’t care for some of the design features from Perkins. I used a conventional rocker arm to operate the exhaust valve and an atmospheric (automatic) intake valve. A vertical shaft was run at 1/2 speed off the crankshaft which carried the ball type governor.

This was the last engine for which I made patterns and castings. Since that time I’ve stuck to billet machined type of parts. I have a Bridgeport type mill which can handle any small engine parts.

Operation -- The ball governor actuates a lever which blocks the exhaust valve when the speed gets beyond a set value. The engine then slows down until the lever backs out and the engine resumes speed. This system worked quite well.




Detail of flyball governor mechanism.

(click on buttons)



All contents © copyright 2013 by E. F. Ellison. All rights reserved.