Early Fokker Biplanes 1916 part 1
In the early days of the war design was more an art than a science. The first prewar aircraft were becoming obsolete and new machines were needed to take their place in combat. Fokker's Eindecker had reached a point where the design could not be improved further. German needed new light scouts to counter French and British designs. Fokker-Flugzeugwerke produced several different models to find a winning design. The D.I was Fokker's first attempt to use an inline water cooled engine instead of a rotary engine to power an aircraft. Although using an inline engine was not successful in this model, the idea was tried again in the D.IV, which was a design closely related to the D.I.
The Fokker D.I (company designation M.18) was a development of the D.II fighter. The D.I was also flown in Austro-Hungarian service as a reconnaissance aircraft under the designation B.III. Confusing the matter further, both the D.II and D.I arrived at the Front in German service at similar times, in July-August of 1916. The main designer on the D.I project was Martin Kreutzer.
Similar to the D.II, the D.I was an unstaggered single-bay equal-span biplane. The upper fuselage was parallel with the upper wing. Unlike the D.II, the D.I was fitted with the 100 hp (75 kW) Mercedes D.I six cylinder water-cooled engine.
Control was achieved using wing-warping instead of ailerons. The wings were also tested in twin bay form. In an attempt to improve visibility, the center section was cut out and the wings were slightly staggered.
These improvements were retained, and the airplane was ordered into production with a 120 hp (89 kW) Mercedes D.II inline engine and a single synchronized 0.312 in (7.92 mm) LMG 08/15 machine gun. The Austro-Hungarian B.IIIs retained the D.I engine, and were armed with a 0.312 in (7.92 mm) Schwarzlose machine gun.
Deliveries of the D.I began in July 1916. The initial production run of 90 aircraft were delivered to the German Fliegertruppen, and 16 to the Austro-Hungarian Luftfahrttruppen (as the B III). Eight were license produced by the Magyar Általános Gépgyár in Hungary.
Several variants were built attempting to improve performance .One Austro-Hungarian B III was experimentally fitted with a 160 hp (119 kW) Mercedes D.III engine. Another had ailerons instead of wing warping, and still another had long span, swept back wings.
Compared with aircraft in service at that time, such as the Albatros D.II and the Nieuport 11, the performance of the Fokker D.I design was decidedly unimpressive. Further production of the D.I did not take place.