The first fighter designed at the works was the Siemens-Schuckert E.I which appeared in mid 1915, and was the first aircraft to be powered by the Siemens-Halske Sh.I, a new rotary, developed by Siemens-Schuckert, in which the cylinders and the propeller rotated in opposite directions. A small number of production machines were supplied to various "Feldflieger Abteilung" to supplement supplies of the Fokker and Pfalz monoplane fighters used at the time mainly for escort work. The prototype SSW E.II, powered by the inline Argus AsII, crashed in June 1916, killing Franz Steffen, one of the designers of the SSW R types. By early 1916 the first generation of German monoplane fighters were outclassed by the Nieuport 11 and the Nieuport 17 which very quickly followed it; and Siemens-Schuckert were supplied with a captured Nieuport 17 to "study". The resulting SSW D.I was powered by the Siemens-Halske Sh.I, but was otherwise a fairly literal copy of the Nieuport 17. This aircraft was the first Siemens-Schuckert fighter to be ordered in quantity, but by the time it became available in numbers (well into 1917) it was outclassed by contemporary Albatros fighters.