Hit & Miss Engines
The name comes from the
method of speed control that is implemented on these engines (as opposed
to the "throttle governed" method of speed control). The sound made
when the engine is running is a distinctive "POP whoosh whoosh whoosh
whoosh POP" as the engine fires and then coasts until the speed decreases
and needs to fire again to maintain its average speed.
Hit and miss engines are four-stroke internal combustion engines that
were conceived in the late 1800s and was produced by various companies
from the 1890s through approximately the 1930s.
Hit and miss engines were
made by a multitude of engine manufacturers during their peak usage
which was from approximately 1910 through the early 1930s when they
began to be replaced by more modern designs. Some of the largest engine
manufacturers were Hercules, International Harvester (McCormick Deering),
John Deere and Fairbanks Morse. A compilation of engine manufacturers
can be found in the book "American Gasoline Engines Since 1872" by C.H.
Wendle. This comprehensive book lists hundreds of manufacturers of early
engines including those that made the hit-and-miss type.
A hit and miss engine is
a type of Flywheel engine. A flywheel engine references an engine that
has a large flywheel or set of flywheels connected to the crankshaft.
The purpose of the flywheels is to maintain engine speed during engine
cycles that do not produce power. The flywheels absorb power on the
combustion stroke and provide power on the other three strokes of the
piston. When these engines were designed technology was not nearly as
advanced as today and all parts were made very large. A typical 6 horsepower
engine weighs approximately 1000 pounds. The engine material was mainly
cast iron and all significant engine parts were cast from it. Small
functional pieces were made of steel and machined to perform their function.
The fuel system of a hit
and miss engine consists of a fuel tank, fuel line, check valve and
fuel mixer. The fuel tank held a quantity of fuel, most typically gasoline.
The fuel line connected the fuel tank to the mixer. Inserted into the
fuel line is a check valve which kept the fuel from running back to
the tank between combustion strokes. The mixer mixes the fuel and air
and had a needle valve to adjust the amount of fuel that gets mixed
with air.
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