It had no Townend ring on cylinders of the radial engine. It was installed in the P-47 Thunderbolt in place of a radial engine. Forward visibility was considered poor due to the large radial engine. These features attempted to improve the aerodynamics of the air-cooled radial engine. DC-3 ,which had a single row radial engine. The smaller frontal area compared with a radial engine also results in less drag. The earliest Hungarian airplane with Hungarian built radial engine was flown in 1913. Cyclone supercharged air-cooled radial engine. It had a Continental W-670 9A seven-cylinder radial engine. The initial M2 model was powered by an air-cooled Wright R-975 radial engine. "L9704" was instead fitted with the Bristol Centaurus radial engine. Wasp Major 4-row 28-cylinder "corncob" radial engine. Whirlwind radial engine provided the best chance of success. A Polish Pezetel radial engine has also been fitted. In August 1941, RAF pilots reported encountering a very fast radial engine fighter over France.