The Armstrong Siddeley Jaguar is an aircraft engine developed by Armstrong Siddeley. The Jaguar was a petrol-fuelled air-cooled 14-cylinder two-row radial engine design. The Jaguar III was first used in 1923, followed in 1925 by the Jaguar IV and in 1927 by the Jaguar VI. In 1925 the Jaguar became the first production aero engine incorporating a geared supercharger.[1]
The Jaguar was developed from the Royal Aircraft Factory RAF.8 design proposal of 1916. The RAF.8 was the work of a design team led by F.M. Green, and incorporated the findings of research into aluminium air-cooled cylinders by Samuel D. Heron and Professor A. H. Gibson. Disillusioned by political and press criticism of the Royal Air Factory, Green and his design team, including Heron, left the Factory in January 1917 and took up positions with the Siddeley-Deasy company. There they were required by official policy to suspend work on the RAF.8 and focus efforts to get the unreliable Siddeley Puma into effective service, an engine that had been ordered in large numbers despite a lack of testing. As a result, the RAF.8 design, then known as the Jaguar, was not run until 21 June 1922.
Initial performance was not as expected; as a result the stroke was increased to 5.5 in (139.7 mm) on all variants after the Jaguar I. By that time, the engine had been fitted with a gear-driven supercharger. Throughout its career the Jaguar suffered from vibration due to the lack of a crankshaft centre bearing.The most powerful version of the engine, the Jaguar VIC, produced a maximum of 490 hp (365 kW) on takeoff at 1,950 rpm and weighed 910 lb (413 kg). The later Lynx was designed using one row of Jaguar cylinders.
A preserved Armstrong Siddeley Jaguar is on public display at the Science Museum (London).