After the failure of his third helicopter, Bertin built a small monoplane also at Puteaux, more or less derived from the early Antoinettes and Deperdussins, with a slender rectangular-sectioned covered rear fuselage. Powered with the new 60 hp flat 6-cylinder 68 kg Bertin, it was brought to the Terrain des Courlis (Curlews Field) at Houeilles in southern France, where Bertin's son Rene flew it for the first time on 25 March 1910. In September Leonce Bertin won a 5000F prize with it at the same field. A year later, in November 1911, it crashed at Chateaufort (now Toussus Le Noble, southwest of Paris). It was fitted with a 2.3-meter diameter Roland propeller.