Construction began in mid-September 1909 and work proceeded rapidly, as the brothers hoped to claim a CHF 1,000 prize put up by the Automobile Club de Suisse for the first Swiss-built aircraft to fly a 1 km closed-circuit.

The Dufaux brothers concluded that the field chosen was too small to give the aircraft enough room to build up speed for takeoff, so they selected a new location for their tests in Viry, in neighbouring France.

The brothers quickly rebuilt the machine in time to display it at an aviation meet at Colombier, but due to the inclement weather, did not attempt to fly it.

By this time the brothers had started building the design, now dubbed the Dufaux 4, in series and were accepting orders for aircraft.

He flew 66 km (41 mi) from St. Gingolph to Geneva at an altitude of around 150 m (500 ft), taking 56 minutes and 5 seconds for the crossing, and collecting a prize of CHF 5,000 that had been put up by the Perrot-Duval Company for this feat.