The Rolls-Royce Merlin is a British-designed V-12 piston aero engine with a liquid cooling system. It was designed by Rolls-Royce as a private venture using experience from their previous Kestrel and Schneider Trophy engines. The engine was first run in 1933 and flew in a Hawker biplane fighter producing 740 hp. Several new aircraft were designed to make use of the Merlin’s high power output and relatively low weight. In 1935 the Hawker Hurricane flew with a 1,030 hp. Merlin and was joined in 1936 by the Supermarine Spitfire and the Fairey Battle light bomber.
Between 1939 and 1945 the Merlin saw operational service in 19 different types of aircraft plus large families of Spitfires and Mosquitos. A major design change to the supercharger coupled with 100-octane fuel resulted in increased power output. Ratings in service ranged from 1,000 hp. to over 2,000 hp (Merlin 66, 1944). In 1945 a Merlin was flight tested at 2,200 hp. During this time the specific weight had improved from 1.4 to 0.8 lb per horsepower. The engine was also produced post war for civil aircraft such as the Avro Tudor and the Canadair North Star. This engine incorporated a two-speed, two-stage supercharger and was rated up to 1,760 hp.
Merlin production at Rolls-Royce was shared by Ford in the U. K. and Packard and Continental in the USA. A total of 168,000 Merlin engines were built – over 55,000 of these in the USA between 1941 and 1945.
The combination of the North American Mustang and the Merlin engine made a superb long-range fighter that could escort bombers on long flights. Continual development of the Merlin ensured it was the powerplant for many wartime aircraft, the Spitfire, Lancaster and Mosquito being the best known.
The capacity of the Merlin was quite small when compared to the opposition. The Merlin had a capacity of 27 litres, whereas the DB601 of the Messerschmitt 109 was 36 litres (1,175 hp.) and the BMW801 engine of the Focke-Wulf 190 had 42 litres (1,700 hp.).
The engine on display is a Packard-built Merlin 224 with a two-speed single stage supercharger. The engine was rated at 1,680 hp at sea level and could produce 1,500 hp. at 9,000 feet. This engine was used to power the Canadian-built Lancaster X.
This engine is a contemporary of the Allison V-1710 also on display at the Museum.
Technical Details: Rolls-Royce Merlin 224
Displacement: 1647 cu in (27 litres)