Formed in 1906 to first produce automobiles, Rolls-Royce was asked to begin designing and building aircraft engines at the outbreak of World War I in 1914. Design of the Merlin began in 1933 following the similar Kestrel design, and helped pioneer high-output, liquid-cooled engines. Early Rolls-Royce Merlin Mk II and Mk III engines, producing about 746 kW (1,000 horsepower), powered Hawker Hurricanes and Supermarine Spitfires in the Battle of Britain. Engine improvements and progress in supercharger performance increased the Merlin's rated power to over 1,715 kW (2,300 horsepower) by the end of the war.
Built at the Rolls-Royce Hillington factory in Glasgow, Scotland, and first tested in September 1944, this engine is a prototype in the Merlin 100 series. A new class of engine, built to meet higher performance standards for power and altitude, Merlin 100s powered the de Havilland Mosquito, Avro Tudor, and de Havilland Hornet and Sea Hornet.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.