engine, where the V12 version has a displacement of and a power output of . Usage in airplanes 1900s to 1930s Five years after the first V12 engine was introduced, Renault introduced the first V12 engine for aircraft in 1909. This engine had a V-angle of 60 degrees, air cooling and an intake over exhaust (F-head) valve arrangement. It had a displacement of , a weight of and produced at 1,800 rpm. The propeller was driven from the front end of the camshaft, thus spinning the propeller speed at half the speed of a typical crankshaft driven propeller, in order to improve the propeller efficiency. The Renault engine was closely mimicked by the RAF 4 and its derivatives, which was used by various British military aircraft during World War I. The RAF 4 engine had a displacement of , weighed and produced at 1,800 rpm. In March 1914, a prototype version of the Sunbeam Mohawk V12 engine was unveiled in the United Kingdom, based on the 'Toodles V' motor racing engine. The production version was rated at at 2,000 rpm, making it the most powerful airplane engine in Great Britain at the outbreak of World War I. During and after World War I, various companies in the United States produced the Liberty L-12 engine. In Austria, the Austro Daimler V12 engines were used by the large flying boats of the Naval Air Force and produced up to . By the end of World War I, V12s were well established in aviation, powering some of the newest and largest fighter and bomber airplanes. After World War I, many Zeppelins used V12 engines built by Maybach and Daimler. V12 engines powered the first transatlantic crossings by the Curtiss NC flying boats (using four Liberty L-12 engines), the first non-stop transatlantic crossing in a Vickers Vimy (using two Rolls-Royce Eagle engines) and the first transatlantic crossing by an airship in the R-34 class airship (using five Sunbeam Maori engines). 1940s to present V12 engines reached their apogee during World War II with engines such as the British Rolls-Royce Merlin and Rolls-Royce Griffon, the Soviet Klimov VK-107 and Mikulin AM-38, the American Allison V-1710, and the German Daimler-Benz DB 600 and Junkers Jumo. These engines generated about at the beginning of the war and over at their ultimate evolution stage. This rapid increase in power outputs was due to technology such as multi-speed superchargers