Halberstadt D.II  The Halberstadt D.II was a biplane fighter aircraft developed and manufactured by German aircraft company Halberstädter Flugzeugwerke. It was adopted by the "Luftstreitkräfte" (Imperial German Army Air Service) and served through the period of Allied air superiority in early 1916. As the first biplane configuration fighter aircraft to serve in combat for the German Empire, it had begun to be superseded in the "Jagdstaffeln" and other early German fighter units by the superior Albatros fighters in the second half of the year, although small numbers of Halberstadts continued in use well into 1917. The D.II was the production version of the experimental D.I. Key differences between the D.I and D.II included a substantial effort to lighten the aircraft in order to improve its performance; the latter also featured staggered wings and the adoption of a more powerful 120 hp Mercedes D.II engine. The side and frontal radiators that had been tried in the D.I were replaced by a wing mounted radiator, similar to the arrangement that was later used by the Albatros D.III and D.V. In comparison with the D.I, the pilot sat higher in his cockpit, to improve his view over the top wing. This required a dorsal turtleback fairing over the rear fuselage, to improve its lines. The two bay wings were very strongly braced, but the trailing edge was composed of a wooden member, as opposed to the wire or cable common on many of the First World War-era German single-engined aircraft. Photographic evidence indicates that many examples were rigged with washout on the lower wings – giving the impression of a curved or twisted lower wing trailing edge. In some photos even the upper wings have a similar sort of "trailing edge droop" on the fixed section inboard of the ailerons. Lateral control was by ailerons, but the Morane-style empennage (common not only to Moranes, but also to the Fokker and Pfalz types of the period) was retained. The inevitable result was extreme fore-and-aft sensitivity and poor control harmonization. The D.II was nonetheless considered to be very manoeuvrable in skilled hands: in particular it could reputedly be dived safely at high speed. A single synchronised lMG 08 "Spandau" machine gun fired through the propeller arc.