02/28/2009. Remarks by Kees Kort: "In 1915, Franz Steffen, chief designer of the Siemens-Schuckertwerke GmbH (Siemensstadt, near Berlin, Germany) designed a single-seat fighter monoplane. The machine was of conventional construction, with warp control instead of ailerons, the landing gear was a very sturdy construction fitted with springs. Armament was one fixed machine gun firing through the propeller.

The first example appeared in the autumn of 1915 and was powered by an 100 hp Siemens & Halske Sh I, and only the first example was fitted with the pictured pointed spinner on the propeller. There was a production order of 20 machines which got the designation E.I. (Eindecker I), the first monoplane ordered from Siemens-Schuckert by the German AAS, although the machines did not see active service as in 1916 they were already obsolete.

One example of a development machine was built, which got the designation E.II. This machine was fitted with a 120 hp Argus As II in-line engine, completely changing the front side of the machine. In June 1916 Franz Steffen crashed to his death in this machine, when he demonstrated it at the flying field in Döberitz. Another version of this monoplane was developed which was virtually an E.I but differed in the engine, a 100 hp Gnome engine. Very few examples of this machine were built."