The Armstrong Siddeley Lynx is a British seven-cylinder aero engine developed by Armstrong Siddeley. Testing began in 1920 and 6,000 had been produced by 1939. In Italy Alfa Romeo built a 200 horsepower (150 kW) licensed version of this engine named the Alfa Romeo Lynx.
Lynx I1920, 150 hp.
Lynx II1920, 184 hp.
Lynx III1924, 200 hp.
Lynx IV1929, 180 hp.
Lynx IVA1930, 188 hp.
Lynx IVC1929, 208/225 hp.
Lynx IV(G)1929, Geared propellor drive.
Lynx IV(MOD)1929, 188 hp, reconditioned and modified Lynx IV.
Lynx IV(S)1928, 200 hp, Fully supercharged.
Lynx V (Lynx Major)1930, increased bore and stroke, name changed from Lynx V to Lynx Major then Cheetah. Effectively half a
PantherPiaggio P.IILicence production in Italy by Piaggio.
Breda Ba.19Breda Ba.25IMAM Ro.10Avro Tutor, K3215, powered by a Lynx IV, flies regularly at the Shuttleworth Collection and can be viewed in the museum at other times.Data from Lumsden
Type: 7-cylinder air-cooled radial engineBore: 5.0 in (127 mm )Stroke: 5.5 in (140 mm)Displacement: 756 cu in (12.4 L)Length: 45.6 in (1,158 mm)Diameter: 42 in (1,067 mm)Dry weight: 525 lb (238 kg )Valvetrain: Overhead valve, 2 valves per cylinderFuel system: CarburettorCooling system: Air-cooledPower output: 187 hp (139 kW) at 1,700 rpm cruise / 215 hp (160 kW) at 1,900 rpm maxPower-to-weight ratio: 0.35 hp/lb (0.6 kW/kg) 
