[1] 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 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.

His Halberstadt was painted bright blue[1] – one of the first documented instances of the gaudy personal finishes applied by German fighter pilots to their mounts for the remainder of the war.

The licence-built Aviatik and Hannover-constructed examples of the Halberstadt D-series fighters usually had IdFlieg-issued serial numbers on their rear fuselage sides.

[4] Manfred von Richthofen flew a red Halberstadt D.II for a few weeks in March 1917, after the spar of the lower wing of his Albatros D.III cracked in combat.

Leutnant Nebel used a set of four improvised tubular launchers, two mounted per side on the wings, with a signal rocket being fired from each tube for the unofficial trial.

By early 1917, the FT-Versuchsabteilung was making combat trials with the radio gear with Halberstadt D.III and D.V aircraft and by late September 1917 with the famous Jagdgeschwader I unit commanded by Manfred von Richthofen, especially Jasta 4.

It also used the D.III version's Argus As.II engine and changed the mounting position of the aircraft's 7.92 mm (.312 in) lMG 08 machine gun from the right to the left side of the nose.

[2] Data from German Combat Planes,[7] Halberstadt Fighters-Classics of World War I Aviation, Volume 1[2]General characteristics Performance Armament