Gnome-Rhône 18L

18L
Type	Radial engine
National origin	France
Manufacturer	Gnome et Rhône

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.

Data from

...
Wikipedia