The Fokker E-series fighters were obsolescent by the spring of 1916, and as part of the German effort to find a successor Albatros developed the D I that first flew in August 1916 with a well streamlined plywood-covered fuselage, equal-chord biplane wings and a Benz Bz.III or Mercedes D.III inline engine whose 112 or 119 kW (150 or 160 hp) allowed the installation of two guns without serious degradation of the fighter’s high performance. The type was soon in service, and proved superior in all important respects to current Allied fighters. The sole criticism levelled at the type was the location of the upper wing, which impaired the pilot’s upward field of vision, and in the definitive D.II the wing was lowered, the D.III engine standardized and, in later aircraft, the fuselage ear-type radiators exchanged for a faired radiator in the upper-wing centre section. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

As soon as the D.II was in production, its designer turned to a more advanced version intended to offer considerably improved manoeuvrability. The result was the D.III that retained the fuselage and empennage of the D.II but added a version of the D.III engine with a higher compression ratio for slightly more power, and adopted a new wing cellule without stagger. The wings comprised a longer-span upper wing with raked tips and a narrow-chord lower wing in a sesquiplane arrangement with V-layout interplane struts. At the same time the radiator was shifted from the centre section to the starboard wing so that a bullet puncture would not result in the pilot being scalded. The D.III entered service in the spring of 1917, and was produced in large numbers to become the decisive fighter over the Western Front between that time and the autumn of the same year. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

In a effort to keep its basic fighter design competitive with the Allied fighters that began to appear during 1917, Albatros developed a much improved version of the D.III with a fuselage of deeper, elliptical cross-section to reduce drag and thus boost performance, a factor in which the larger-diameter propeller spinner played its part. Other changes were further reduction in the height of the upper wing above the fuselage, a revised rudder, a pilot’s headrest that was often removed, and a different aileron control system. The D.V entered service in May 1917, and was soon joined by the D.Va that reverted to the upper wing and aileron control system of the D.III. Very large-scale production of both variants was undertaken, but the design was outmoded and could not match the latest Allied fighters. The lower wing was also weak, and tended to break away in a steep dive. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

Perhaps the best known German fighter of World War I because it was flown by such aces as Manfred von Richthofen, the Dr.I was an indifferent performer in all aspects of air combat but climb and agility, in which it possessed almost legendary capability. The Dr.I was inspired by the Sopwith Triplane, but took the triplane formula to extremes in maximizing wing area while minimizing overall span. Designed by Reinhold Platz, the Dr.I had a rotary engine, steel-tube fuselage and virtually cantilever wings of wooden construction with ply skinning over their forward surfaces. The type entered service in August 1917, and 420 were built up to May 1918, by which time its low performance was a distinct liability in the hands of all but the most capable of pilots flying purely defensive sorties.  (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

When it appeared in the late summer of 1915, the Fokker E.I was the world’s first true fighter, for despite its poor performance and indifferent monoplane structure (derived from its M.5k unarmed predecessor) it was armed with a machine-gun enabled to fire directly forward through the propeller disc by the world’s first practical interrupter gear. The E.I (few built) was underpowered, and succeeded by the E.II with greater power (23 built) and then by the definitive E.III (between 120 and 150 built) with the same engine but a number of detail improvements. This was the aircraft of the 1915/16 ‘Fokker Scourge’ in which these poor aircraft prevailed because of their armament and the skill of their pilots. Allied developments prompted the E.IV with two guns and greater power, but this lacked any real agility. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

(source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

The Halberstadt D-series of single-seat fighters was developed from the unarmed B.II reconnaissance two-seater, inheriting that type’s considerable structural strength. The D.I appeared late in 1915 with a single interrupted gun and a powerplant comprising one 75-kW (100 hp) Mercedes D.I inline engine. The production model, of which few were built, was the D.II with the more powerful Mercedes D.II engine and a wing radiator in place of the original nose-mounted unit. These served for a few months from June 1916 before being supplanted by the D.III, which differed mainly in its larger horn-balanced ailerons and as powerplant one 89-kW (120 hp) Argus AS.II inline. A few D.IV’s were produced for Turkey with twin guns and the 112 kW (150 hp) Benz Bz.III, and the D.V of 1917 was a refined type with more streamlined plywood-covered fuselage and the As.II engine. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)

The D.I was in essence the C.II two-seater scaled down as a single-seat fighter. The type was nicknamed Haifisch (shark) for its deep fuselage with the slightly swept upper wing attached directly to it. The D.I first flew in July 1916, and was produced in small numbers. The definitive version was the D.II, which retained the same 119 kW (160 hp) Mercedes D.III engine but featured a number of drag-reducing revisions as well as a modified empennage. The D.II began to enter service early in 1917, and was complemented by the D.IIa with a more powerful engine. The D.II and D.IIa were not popular in service, pilots complaining about lack of vision and heavy controls. The D.III introduced a revised and shallower fuselage over which the upper-wing centre section was supported on cabane struts, but only a few were built. The single D.V prototype had a more refined fuselage structure. (source: The International Encyclopedia of Aircraft, Oriole Publishing, 1991)