The Armstrong Siddeley Jaguar was an aero 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.
The Jaguar was developed from the Royal Aircraft Factory RAF.8 design proposal of 1917, and was engineered to use a gear driven supercharger. First run on 21 June 1922 initial performance was not as expected, as a result the bore was increased to 5.5 in (139.7 mm) with all variants after the Jaguar I using this dimension. Throughout its career the Jaguar suffered from vibration due to a 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 lbs (413 kg). The later Lynx was designed using one row of Jaguar cylinders.