What type of engine configuration is commonly found on small aircraft?

The horizontally opposed engine configuration is commonly found on small aircraft due to its advantages in performance, weight distribution, and design simplicity. This type of engine has cylinders arranged in a flat configuration, which helps in reducing the aircraft's overall size and weight, ultimately enhancing aerodynamics and fuel efficiency. Additionally, the design provides a lower center of gravity, improving stability during flight. This is particularly beneficial for small aircraft, which often require efficient performance and handling characteristics.

In contrast, radial engines and V-type engines are less common in small aircraft because they tend to be larger and heavier, which is less suitable for the performance requirements of smaller planes. Radial engines, while popular in historical and some military aircraft, are generally used in specific designs to accommodate their cooling needs and power output. Rotary engines, though innovative, have not been widely adopted in modern small aircraft due to concerns regarding reliability and maintenance.