Building Model Engines

By Staff
Published on March 1, 1983
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Orillia, Ontario, Canada L3V 1G6

Shown is my model gas engine. I built this engine last winter
from castings supplied by one of the advertisers in G.E.M. It has a
‘ bore and 1′ stroke. The flywheels are 4’ in diameter.
It runs best on regular gasoline and the mixer or carburetor uses a
sewing needle to control the mixture. I used oak planks to make the
base and the gas tank is a piece of brass tubing off an old sink
drain. The base contains the coil, condenser, and battery, which
makes it all self-contained and easy to run sitting n the
shelf.

I have displayed this engine at several steam shows and fairs
and it always draws a crowd. Some people get quite angry when I
insist that it runs on its own. They think there is a trick to it
somewhere. I think that it ran about 100 hours this past summer at
the shows. One full gas tank (3 ounces) will run about five hours
if it is just idling. The governors are quite sensitive and will
keep the hit and miss cycle going even when the speed is slowed
right down. However, as soon as a load is applied, it jumps to life
and hits every time until the RPM’s come up again. When the
load is removed, the firing stops completely and it coasts right
down to the occasional ‘putt’ followed by several seconds
of whirring timing gears and coasting flywheels. I’m sure this
type of running will be familiar to anyone who owns a hit and miss
engine. Many people however, don’t understand what keeps it
going because they are only used to throttle-governed engines.

I’d like to correspond with anyone in Gas Engine Country who
is also building model engines. My current project is a 1915 Holt
Caterpillar engine. It is a four cylinder with 1′ stroke and
1′ bore. If I can get enough information about the Holt 75
tractor, I would like to model the whole thing. According to the
scale of the engine, the finished model would be about 32′
long. These tractors had tracks at the back and one large wheel on
a swivel at the front.

As the costs of transporting full size equipment continues to
rise I expect to see miniatures increase in popularity. I expect
that there are others in the Gas Engine Hobby who have a special
make of engine which is a favorite or a ‘dream engine’. For
most of us the only way of owning one is to build a model of that
very special engine. They can be just as much fun to run as the
real thing!

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