This engine was a double form of the Z9, which had nine cylinders. Salmson aircraft engines that were produced in France starting in 1913 by the Societe des Moteurs Salmson in Billancourt, Sein were originally designed and patented by Canton and Unne, and also constructed in Great Britain by the Dudbridge Iron Works, Ltd. of Strand, Gloucester. Salmson was said to have built some in-line engines, as well as barrel-type engines, but finally abandoned those types in favor of the radial cylinder arrangement.
Development work on water-cooled radial aircraft engines began in 1908, making it one of the earliest companies to produce power plants of this type. Whereas most other radials were air-cooled, Salmson engines demonstrated the real advantages of all versions of this type, and were the first successful large radials.
The Salmson Type Z18 powered Hanriot, Breguet, Caudron, and Morane aircraft. Twenty-five of these engines were constructed between 1918 and 1919.