80 hp (60 kW) le Rhône engines were made under license in the United States by Union Switch and Signal of Pennsylvania, and the 110 hp (82 kW) Oberursel Ur.II rotary engine used by Germany in World War I, in such famous fighters such as the Fokker Dr.I triplane, was a close copy of the 110 hp (82 kW) le Rhône 9J version.[1]