A fly wheel, or hit or miss engine is defined as an engine that uses a set of flywheels, or one flywheel attached to a crankshaft for the sole purpose of maintaining engine speed by storing energy. A hit and miss engine, is a certain type of fly wheel engine that was first created in the late 19th century. Though there is not one company credited with the creation of fly wheel engines, they were in demand from the early 1900s to approximately 1940. Many companies utilized fly wheel engines until new technology created methods that are more modern. During the late 1940s, fly wheel engines ceased to be utilized, as they were replaced by internal combustion engines capable of delivering greater horsepower. However, modern-day fly wheel engines are seen in the oil production industry.

Fly wheel engines are a type of internal combustion piston engine that uses a crankshaft, piston, valves, spark plugs, both intake and exhaust camshafts, and connecting rods to create heat, then store and transfer it as energy. The engines operate by turning pressure into circular motion, thereby creating energy. Like other internal combustion engines, fly wheel engines required some source of fuel that would be heated inside a cylinder or mixed with air in order to create the internal combustion. In fly wheel or hit or miss engines, the piston uses the fly wheel in order to return to the cylinder, where it repeats the process. Fly wheels not only help the process to completion, but are also used to store the energy as the engine completes its power cycle.

The fly wheel was a regular feature in a number of companies that created engines. Some of the most popular companies known for using fly wheel engines, such as the hit and miss, include the 19th century company Fairbanks Morse, Novo Engine Company, Baker Monitor, Fuller and Johnson, Witte Engine Works, International Harvester Company, and John Deere. These companies relied upon the fly wheel engine as a source of slow, but reliable power. They were useful for providing energy sources for generators, devices such as washing machines, and for early power saws. Farmers frequently used them to save time and energy.

A number of late 19th century pumps were powered with hit and miss, fly wheel engines. They are considered slower units than what is available in modern times and antique fly wheel engines often delivered between 1 and 100 horsepower. Though many companies use faster engines capable of greater horse power, the engineering company, Arrow Engines, continues to create fly wheel engines. Most hit and miss, fly wheel engines had an open crank case that made it easy to see the engine’s components. Because the crankcase was open, it was not uncommon for these engines to spew oil, grease, or other lubricants while the engine was in operation. This was viewed as a major drawback and was one of the factors that led to the phasing out of these engines in the 40s.

Fly wheel engines posed several problems in addition to their slow speed. The units were very heavy, making them difficult for use in applications that required movement or easy transportation. Today, many people view hit and miss and fly wheel engines as relics of the ancient past and early features from the industrial revolution. The company Jaeger Machine had developed a fly wheel engine used for their cement mixer. The mixers were small-scale, but used the engine for the purpose of mixing concrete and removing the time and energy that workers would expend performing the work by hand. Witte developed a five horsepower throttle engine that was in demand by farmers during the early 20th century. Though the older style hit and miss or fly wheel engines are no longer developed in modern times, those who collect these engines often have great success restoring them to working condition. Fly wheel engines are an important part of industrial history and though they ceased production in the 40s, continue to impress curators to this day.