The only attempts to produce twin-row rotary engines in any volume were undertaken by Gnome, with their Double Lambda fourteen-cylinder 160 hp design, and with the German Oberursel firm's early World War I clone of the Double Lambda design, the U.III of the same power rating. While an example of the Double Lambda went on to power one of the Deperdussin Monocoque racing aircraft to a world-record speed of nearly 204 km/h (126 mph) in September 1913, the Oberursel U.III is only known to have been fitted into a few German production military aircraft, the Fokker E.IV fighter monoplane and Fokker D.III fighter biplane, both of whose failures to become successful combat types were partially due to the poor quality of the German powerplant, which was prone to wearing out after only a few hours of combat flight.