The Pfalz D.VI was a rotary powered biplane fighter that was approved for service in 1917 but never entered production.
The first Pfalz designed fighters had been a series of monoplanes based on the Morane-Saulnier Type H, starting with the Pfalz E.I. However these aircraft had always lagged behind the Fokker E.I and its successors, and had only been produced in small numbers before structural problems meant they were withdrawn. Pfalz was then used to build biplane Roland fighters, although these were also generally inferior to their contemporaries, and this appears to have been done to keep the factory working.
Pfalz’s own first attempt to produce a biplane was the D 4, which had been based on the Pfalz E.V monoplane, but this hadn’t been a success. During 1917 they would have more success, most famously with the Pfalz D.III, powered by a Mercedes D.III six cylinder air cooled in-line engine
However the D.III wasn’t the first Pfalz biplane to fly in 1917. That honour went to the Pfalz D.VI. Like the D.III this was influenced by the successful Nieuport sesquiplane fighters that had ended the dominance of the Fokker monoplanes, although it differed in many details.
The D.VI was powered by a 110hp Oberursel Ur.II rotary engine. The fuselage had a circular cross-section which blended smoothly into the engine. Like the Nieuports it was a single bay biplane with a single ‘V’ strut connecting the upper and lower wings. Unlike the Nieuports the lower wing had two wing spars, making it more rigid than the smaller single spar wing of the Nieuport fighters. The lower wing was still smaller than the upper wing, but not by as much as on the Nieuports. The wings had pointed tips, with controls on the upper wing and a cut-out above the pilot’s position. Compared to the slightly later Pfalz D.III it was a smaller and lighter aircraft.
The D.VI made its maiden flight in January 1917. However progress then slowed down, and it didn’t undertake its type tests until September 1917, by which point it was armed with two Spandau machine guns. It was successful enough to be provisionally approved for service, but it didn’t enter production, possibly because Germany had a limited supply of castor oil, the most suitable lubricant for rotary engines.
The Pfalz D.VI took part in the First Fighter Competition at Adlershof in February 1918, where it proved to be slower than the Pfalz D.VII, which used the 160hp Seimens-Halske Sh.III counter-rotary engine. As a result the D.VI was eliminated from the contest.
Engine: Oberursel Ur.II
Span: 7.08m (upper), 6.30m (lower)
Empty weight: 416kg
Loaded weight: 606kg
Climb Rate: 16min to 5,000m, 25min to 6,000m
Armament: Two Spandau LMG 08/15 machine guns