Salmson_AD.9
British Salmson aero-engines refers to a series of small French designed, air-cooled radial aero engine that were produced by British Salmson Aero Engines Ltd, under license from Société des Moteurs Salmson, in Great Britain during the late 1920s and 1930s.
Because the relatively low power was divided among several cylinders, the running of the engines was particularly smooth, and the torque was very even.[1] Adding to the smooth running of these engines was the use of the Canton-Unne system of planetary gears in a cage connecting pistons to crank-pin.