Please answer the following question: Information: - The Battle of Britain (German: "die Luftschlacht um England", literally "Air battle for England") was a combat of the Second World War, when the Royal Air Force (RAF) defended the United Kingdom (UK) against the German Air Force (Luftwaffe) attacks from the end of June 1940. It is described as the first major campaign fought entirely by air forces. The British officially recognise its duration as from 10 July until 31 October 1940 that overlaps with the period of large-scale night attacks known as the Blitz, while German historians do not accept this subdivision and regard it as a campaign lasting from July 1940 to June 1941. - The de Havilland Engine Company was an offshoot of the de Havilland aircraft building company, which started life as the 'Engine Division of the de Havilland Aircraft Company' in 1926 producing the famous de Havilland Gipsy aero-engine. The company was merged with Bristol Siddeley (BSEL) engines in 1961 with BSEL subsequently becoming part of Rolls-Royce Limited in 1968. - The Royal Air Force (RAF) is the United Kingdom's aerial warfare force. Formed towards the end of the First World War on 1 April 1918, it is the oldest independent air force in the world. Following victory over the Central Powers in 1918 the RAF emerged as, at the time, the largest air force in the world. Since its formation, the RAF has taken a significant role in British military history, in particular, playing a large part in the Second World War where it fought its most famous campaign, the Battle of Britain. - The de Havilland Gipsy is a British air-cooled four-cylinder in-line aircraft engine designed by Frank Halford in 1927 to replace the ADC Cirrus in the de Havilland DH.60 Moth light biplane. Initially developed as an upright 5litre (300cubic inch) capacity engine, later versions were designed to run inverted with increased capacity and power. - Bristol Siddeley Engines Ltd (BSEL) was a British aero engine manufacturer. The company was formed in 1959 by a merger of Bristol Aero-Engines Limited and Armstrong Siddeley Motors Limited. In 1961 the company was expanded by the purchase of the de Havilland Engine Company and the engine division of Blackburn Aircraft. Bristol Siddeley was purchased by Rolls-Royce Limited in 1968. - De Havilland Aircraft Company Limited was a British aviation manufacturer established in late 1920 by Geoffrey de Havilland at Stag Lane Aerodrome Edgware on the outskirts of north London. Operations were later moved to Hatfield in Hertfordshire. - Rolls-Royce Limited owned a British luxury-car and aero engine manufacturing business founded in 1904 by Charles Stewart Rolls and Sir Frederick Henry Royce. Rolls-Royce Limited was incorporated on 15 March 1906 as a vehicle for their ownership of their Rolls-Royce business. Their business quickly developed a reputation for superior engineering quality, "best car in the world", building on F H Royce's existing standing. Rolls-Royce became a leading manufacturer of piston aero-engines after it was brought into building them by the first World War . - The de Havilland Gipsy Twelve was a British aero engine developed by the de Havilland Engine Company in 1937 . Approximately 95 were manufactured . It was known as the Gipsy King in Royal Air Force service . - The Central Powers , consisting of Germany, , the Ottoman Empire and Bulgaria hence also known as the Quadruple Alliance was one of the two main factions during World WarI (191418). It faced and was defeated by the Allied Powers that had formed around the Triple Entente, after which it was dissolved. What is the relationship between 'de havilland gipsy twelve' and 'aircraft engine'?
Answer:
subclass of