Kondor D 1
The Kondor D 1, given the unofficial name Kondorlaus, was a German single seat, biplane fighter aircraft designed and built close to the end of WWI. Design and development. The Kondor D 1 was an unequal span single-seat biplane of wooden construction, powered by a Gnome Monosoupape rotary engine and armed with two LMG 08/15 Spandau machine guns. The D 1 had a single spar lower wing with V interplane struts, similar to Nieuport 11 practice. The first flight of the Kondor D 1 occurred in the autumn of 1917, but test flights showed it to  be underpowered and Walter Rethel, with Paul Ehrhardt, developed an improved version of the design, the Kondor D 2, which Rethel completed after Ehrhardt retired due to ill health. Confusion reigned after the second D-type competition at Aldershof because the Idflieg referred to the two Kondor D 2 prototypes as the D.I and D.II during the competition, which were actually fictitious designations.