Radial engines are a type of internal combustion engine where the cylinders are arranged in a circular pattern around a central crankshaft. This design allows for a compact engine that can produce a lot of power relative to its size. Radial engines were commonly used in aircraft during the early to mid-20th century, particularly in World War II planes. One of the key advantages of radial engines is their ability to cool efficiently, as the airflow around the cylinders helps dissipate heat. They are also known for their distinctive sound and unique appearance. Notable examples of radial engines include the Pratt & Whitney R-1340 and the Bristol Pegasus.