By the end of the 19th century, the development of the internal combustion engine triggered a revolution in transportation, first with the automobile and then the aeroplane. In 1890, Clément Ader of France reportedly flew his steam engine-powered "Eole" about 50 meters at a height of 20 centimeters off the ground. Ader called his invention an "Avion", for Appareil Volant Imitant les Oiseaux Naturels (flying apparatus imitating natural birds).

Aeronautics takes off with the Gnome

A few years later, in 1895, a 26-year old French engineer named Louis Seguin opened his first factory in the Paris suburb of Gennevilliers. He bought the license for the Gnome gas engine from the German firm Motoren Fabrik Oberursel.

On December 17, 1903, the Wright brothers' Flyer made a sustained flight of about 12 seconds with Orville Wright at the controls, opening the modern era of aviation. At about the same time, Louis Seguin (along with brother Laurent) was diversifying production by building engines for industrial applications. On June 6, 1905 he founded the "Société des Moteurs Gnome." The new company started with ship then automobile engines, before embarking on a new market: rotary engines for airplanes.

At the time there was no such thing as an airplane engine. The many manufacturers of internal combustion engines (Panhard-Levassor, Peugeot, Clément-Bayard, Ader, Aster, Darracq, Chenu, etc.) merely adapted automotive engines for aeronautics. A real purpose-built airplane engine had yet to make its appearance.

After 15 months of development, the Seguin brothers rolled out their first production airplane engine in the spring of 1909. The Gnome Omega weighed 75 kilograms (165 lb), and delivered an unprecedented 50 horsepower. More than 1,700 of these engines would be built in France, along with license-built models in Germany, Sweden, Great Britain, the United States and Russia. As early as 1909, the Gnome powered Henry Farman's Voisin to new world records for distance and endurance - 180 kilometers and 3 hours 15 minutes.

Omega-powered aircraft broke the 100 kph mark in 1910, and would soon chalk up 30 world records. The aviation industry was flourishing, as a number of new manufacturers made their appearance: Antoinette, Henry Farman, Esnault-Pelterie and Blériot, to name a few of the French marques.

France had become the uncontested world leader in aircraft construction. Louis Blériot made the first crossing of the English Channel on July 25, 1909, and aerial meetings and races sprung up like mushrooms. The popular press reported extensively on the adventures of these new "knights of the sky". Starting in the teens, the rotary engine became lighter, with added cooling and more efficient operation.

1911 : the Le Rhône 9C steps up

Another French engineer, Louis Verdet, designed his own rotary aero-engine in 1910. Two years later, he produced a 7-cylinder prototype weighing 90 kilos and developing 70 horsepower. That same year he founded the Société des Moteurs Le Rhône on Boulevard Kellermann in Paris. This is where he produced the famous Le Rhône 9C, an 80-hp 9-cylinder rotary engine that would power numerous models of aircraft during WWI.

Like the Gnome, the Rhône was also built under license in Germany, Austria, Great Britain and Sweden. Gnome and Rhône were fierce competitors at all levels, with their pilots leading the charge. On September 23, 1913, Roland Garros made the first crossing of the Mediterranean in a Morane-Saulnier monoplane, powered by a 50-hp Gnome rotary engine.