The Rolls-Royce Merlin is a British aircraft engine that was widely used during World War II. It is a liquid-cooled V12 engine known for its reliability and power, producing up to 1,600 horsepower. The Merlin was instrumental in the performance of several iconic aircraft, including the Supermarine Spitfire and the Avro Lancaster. Developed in the 1930s, the Merlin engine featured advanced technology for its time, such as a two-stage supercharger. Its design allowed for high-altitude performance, making it a favorite among pilots. The success of the Merlin contributed significantly to the Allied victory in the war.