Salmson 5 / 5 Ac / 5 Ap-01 / 5Aq-01
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.
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.