British Salmson AC.7
After their successful water-cooled radial engines, developed from 1908 to 1918, Salmson changed their focus to air-cooling to reduce weight and increase specific power (power per unit weight). The majority of the engines produced by Salmson were of radial type with a few other arrangements such as the Salmson T6.E. In common with other engines produced by this manufacturer, the air-cooled radial engines featured the unorthodox Canton-Unné internal arrangement that dispensed with a master rod in favour of a cage of epicyclic gears driving the crankpin. Built from 1920, production ended in 1951 with the liquidation of the manufacturing company.
The 3,7 and 9 cylinder Salmsons were license built in Great Britain, during the 1920s and 1930s, by the British Salmson engine company as the British Salmson AD.3, British Salmson AC.7, British Salmson AC.9, and British Salmson AD.9.
In common with several other French aero-engine manufacturers Salmson named their engines with the number of cylinders then a series letter in capitals followed by variant letters in lower-case.
Type: 7-cyl radial
Bore: 100 mm (3.937 in)
Stroke: 130 mm (5.118 in)
Capacity: 7.150 l (436.32 cu in)
Power: 41 kW (55 hp) at 1,800rpm