Closeup of Otto Parschau's personal <a href="https://en.wikipedia.org/wiki/Parabellum_MG14" class="extiw" title="en:Parabellum MG14">Parabellum MG14</a>-armed Fokker A-series monoplane, early June 1915, and basically the "prototype" aircraft for the armed Fokker E-series Eindecker fighters.
Unknown author<span style="display: none;">Unknown author</span>
Scan from Windsock Datafile No.91, page 7, photo from the Peter M. Grosz collection