Louis Verdet (1869-1918) studied at the School of Arts and Crafts in Aix-en-Provence.

“Louis Verdet”

-Louis Verdet was a pioneer of aviation engine design. In France, he is credited with inventing the rotary radial engine. Perhaps the first practical rotary radial engine.

-He worked as an engineer at the Rossel-Peugeot factory in Suresnes, while developing a seven-cylinder engine with 55 cv at 1,300 rpm. (1909).

-In a sense, he reduced the power-to-weight ratio of existing engines by almost half.

“Verdet 7-cylinder at the Safran Museum”

- Production began in partnership with a financier, but failed. He did another attempt in 1911 with Edouard Martin, with whom he founded the “Société des Moteurs Le Rhone.”

- However, in the previous two years, Verdet engines had already gained fame.

“Le Rhône ad”

- Le-Rhone engines were often treated as Verdet engines, especially at the beginning. (See Le-Rhone and Gnome-Rhone.)

- Since 1913, an attempt had been made to merge Gnome with Le-Rhone to increase production capacity at the request of the French authorities.

-There were many meetings and studies aimed at the merger, which culminated in 1915 with the acquisition of Le-Rhone by Gnome, thus bringing the Seguin brothers and Verdet together on a common path.

"Common logo"

-The Le-Rhone engines would continue to be produced alongside the Gnome engines in the new company.

-Different in several respects, the use of two valves controlled in the cylinder head, which eliminated the common problem of the piston-head valve sticking that the Gnome engines had, much to the despair of pilots and mechanics.

From Appendix 6: The engine of this pioneer of radial rotary engines is now shown complete in side view for better understanding.

"Verdet rotary engine"

-We note that it has valves and that the control mechanism works by "pulling" thick wires.

-It had seven cylinders giving 65 cv. Its weight was 85 kg.