Gnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp (81 kW) rotary designs, while another 75,000 were produced by various licensees. These engines powered the majority of aircraft in the first half of the war, both Allied designs as well as German examples produced by Motorenfabrik Oberursel.
Gnome et Rhône
160 hp Gnome 9N Monosoupape of 1917
80 hp Le Rhône 9C rotary engine
Bond of the Société des Moteurs Gnome et Rhône, issued 1. July 1924
The rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per row in a radial configuration. The engine's crankshaft remained stationary in operation, while the entire crankcase and its attached cylinders rotated around it as a unit. Its main application was in aviation, although it also saw use in a few early motorcycles and automobiles.
An 80 horsepower (60 kW) rated Le Rhône 9C, a typical rotary engine of WWI. The copper pipes carry the fuel-air mixture from the crankcase to the cylinder heads acting collectively as an intake manifold.
This Le Rhône 9C installed on a Sopwith Pup fighter aircraft at the Fleet Air Arm Museum. Note the narrowness of the mounting pedestal to the fixed crankshaft (2013), and the size of the engine
Megola motorcycle with rotary engine mounted in the front wheel
An 1897 Félix Millet motorcycle