The Gnome et Rhône 18L was a French-designed twin-row 18-cylinder air-cooled radial engine. The 18L was a large step up in terms of displacement, power and number of cylinders. The majority of Gnome-Rhone engines were either 7, 9 or 14 cylinders. The engine proved not to be a success, and it was dropped in 1939 due to a poor power-to-weight ratio. The American and British 18-cylinder engines proved lighter, smaller and generally more reliable.
Gnome Rhone 18L