The Royal Aircraft Factory S.E.5 was a British biplane fighter aircraft used during World War I. Designed by Henry Folland, it first flew in 1916 and became one of the most successful fighters of the war. The S.E.5 was known for its speed, maneuverability, and firepower, featuring a powerful Vickers machine gun and a reliable Wolseley Viper engine. With a top speed of around 138 mph, the S.E.5 played a crucial role in gaining air superiority for the Royal Flying Corps. Its design allowed for excellent visibility and stability, making it a favorite among pilots. The aircraft contributed significantly to the Allied victory in the conflict.