Flat-six Engine - Aircraft Engines

Aircraft Engines

Lycoming developed and currently produces a very successful series of flat-4 and flat-6 aircraft engines, and one flat-8 engine. The configuration is expressed in the engine's model numbers as the letter "O", standing for "opposed" in reference to the cylinder arrangement. Continental Motors is another major manufacturer of flat-4 and flat-6 aircraft engines. Flat engines largely replaced the historically more popular radial engines in small aircraft after World War II because the radials, although they had good cooling, added large frontal area which caused too much drag. It was relatively easy to derive flat-6 and flat-8 engines from a flat-4 design by simply adding more cylinder pairs, and the engines could use many of the same components. The only problem is that in an air-cooled engine there can be cooling problems with the middle cylinder pairs. The flat-6 is more powerful and smoother than the flat-4 aircraft engine, although also more expensive. Jabiru and Rotax are also reciprocating aircraft engine manufacturers, and both are more popular in the experimental, ultralight and new sport category aircraft. In the 1980s, Porsche adapted their 911 unit to become the Porsche PFM 3200 aero engine, but production ceased in 1991.