Hit-and-miss Engine - Later History

Later History

By the 1930s, more-advanced types of engines were being designed and produced. Flywheel engines were extremely heavy for the power produced, ran at very slow speeds, required a lot of maintenance, and could not easily be incorporated into mobile applications. In the late 1920s International Harvester already had the model M engine which was an enclosed version of a flywheel engine. Their next step was the model LA which was a totally enclosed engine (except for the valve system) featuring self-lubrication (oil in the crankcase), reliable spark plug ignition, faster-speed operation (up to about 750-800 RPM) and most of all, light in weight compared to earlier generations. While the 1½ HP (1.1 kW) model LA still weighed about 150 pounds (68 kg), it was far lighter than the model M 1½ HP engine, which is in the 300-350 pound (136 - 159 kg) range. As time passed, more engine manufacturers moved to the enclosed crankcase engine. Companies like Briggs and Stratton were also producing lightweight air-cooled engines in the 1/2 to 2 HP (.37 - 1.5 kW) range and used much lighter-weight materials. These engines also ran at much higher speeds (up to approximately 2000–2500 RPM) and therefore produced far more power per pound than the slow flywheel engines.

With the exception of oil field applications, flywheel engine production ceased in the 1940s.