It was first fitted to the Caudron G 3 with an 80 hp Clerget engine. This was a good start, especially since the Battle of Verdun, which had been raging since February 1916, led to additional orders for aircraft and propellers. Marcel Bloch was then seconded to Hirch Minces: "Starting to have too much work, I asked Potez to come and work with me. He left Caudron's design office without regret. »
As production had to be carried out quickly, Marcel Bloch suggested to Hirch Minckès that he set up a company. The latter consulted several of his friends, including E. Dumaine, general manager of the Société des moteurs Clerget, who encouraged him in this direction. Hirch Minckès and his associate, Edeline, set up the Société des Hélices Éclair, of which Marcel Bloch and Henry Potez were technical directors and to which the army detached them.
Several carpenters came to reinforce their team, while the Clerget company encouraged their business by placing orders for propeller-brakes for its test benches. Their business grew and occupied an entire floor of the furniture factory on Avenue Parmentier, of which they formed a separate section. The two friends subcontract the elements that need to be machined externally: "We had the blades cut on the outside, glued them at his house and then had to have them de-billied. All the furniture manufacturers in the Faubourg Saint-Antoine had begun to build Éclair propellers. »
Their association is a success. The Éclair propellers equip the British reconnaissance Sopwith built under license in France, the Dorand AR and especially the Spad, in particular the Spad VII of the most famous French ace, Georges Guynemer, dear to the heart of Marcel Bloch: "When Guynemer's plane, "Le Vieux Charles" with nineteen victories, was presented at the Invalides as a witness of glory, I went to see him and when I arrived I saw, of course, the propeller. Now it was a propeller that I had studied and built. I felt great satisfaction and perhaps a little pride. »
In 1917, it was a success for the two second lieutenants, and in a few months the Company became one of the four major propeller manufacturers, while there were no less than forty manufacturers and two hundred and fifty-three different series. The Material Inspectorate decided to retain a maximum of three sets of propellers for an aircraft. Among them is the Éclair propeller. Marcel Bloch and Henry Potez thus became aviation legends.