The Albatros D.I was the first in a series of biplane fighters that helped the Germans gain control of the air over the Western Front early in 1917, but it was only produced in small numbers and was soon replaced by the Albatros D.II and Albatros D.III.
During 1915 the Fokker monoplanes dominated the skies over the Western Front. By the start of 1916 the Allies had caught up the introduction of the new British D.H.2 and French Nieuport 11 fighters had seen the Germans lose that control. The German air service decided to order the development of a series of biplanes that could challenge the Allies. The Halberstadt D.II was the first to be ordered into production, in March 1916. They were followed by the Fokker D.I of May 1916. Both of these types entered service in June-July 1916, but neither had a long life-span. The Fokker aircraft suffered from a series of wing failures, and was withdrawn by the end of 1916. Later models failed to address these problems. These early D fighters were powered by 120hp engines, which only provided enough power for them to carry a single machine gun.
Albatros were also working on a biplane fighter early in 1916. The company had produced biplane racing aircraft in 1914, and used this experience to produce a prototype of what would become the D.I. The resulting fighter 'looked right'. The engine was carried within a streamlined nose, aided by the large spinner. The very front of the fuselage close to the engine was rounded, but the sides soon became flat (the D.V introduced an oval cross-section). The fuselage was built around a series of wooden frames (or formers), connected by six main spruce longerons. The outer skin was made up of three-ply plywood which was pinned and glued onto the longerons.
The D.I was a single bay biplane, with the main struts towards the end of the wings and inverted V struts in the centre. The two wings had the same chord (distance from front to back) and similar spans, with the lower wing being very slightly shorter. The wing tips were at a slight angle. Ailerons were carried in the upper wing, and were controlled by a crank lever that was connected to control wires in the lower wing. The fabric covered wings were constructed around two main spars, with three-ply ribs. The front spar was close to the leading edge, the rear spar towards the centre of the wing. At the trailing edge the ribs were connected by a wire.
The D.I was powered by a Mercedes D.III engine which provided 160hp, a great increase on the 120hp engines in use in other German biplane fighters. The only weakness was the fuselage mounted Windhoff box radiators which were vulnerable to battle damage or to leakage. In either case this would cause the engine to seize. Ear and side mounted radiators were banned on German fighters after 10 November 1916 and were replaced during the production run of the Albatros D.II.
The design of the D.I was completed by mid-April 1916. In June Albatros received an order to produce twelve prototypes (presumably including this aircraft). The exact sequence of events is unclear, but this batch of twelve aircraft might have included the prototype for the D.II.
The D.I was a generally successful design. Pilots found it easy to fly. Although it was less manoeuvrable than the Halberstadt fighters or than rotary engined machines it could out-dive most enemy aircraft and was faster than the D.H.2 and more heavily armed then either the D.H.2 or the Nieuport 11.
The aircraft had two flaws that were uncovered in combat trials. The upper wing was set too high, blocking the pilot's view up and forward. The twin guns were aimed through the inverted V centre wing struts, which interfered with the pilot's vision when aiming at fast moving targets. Both of these problems were solved on the Albatros D.II, which was placed into production in August 1916, one month after an order for fifty D.Is had been placed.
The first few D.Is entered service with small fighter flights attached to bomber units (Kampfgeschwadern). These were soon replaced with Jagdstaffeln (or Jastas), large fighter units whose main role was to destroy enemy aircraft that crossed the German front lines. At first the Albatros aircraft operated alongside the Haberstadt and Fokker biplanes, but by the end of 1916 the Albatros D.I and D.II dominated.
The Albatros D.I entered service in large numbers in the autumn of 1916. Jasta 2 received six on 16 September, and scored its first victory with the type on the same day. On the following day the Jasta flew its first operation as a squadron, and by the end of the month had claimed 25 victories, most of them after the arrival of the D.III.
The number of D.Is at the front peaked in November 1939 when fifty were in use. By the end of January 1917 there were still 39 D.Is at the front, but numbers tailed off during 1917. By November there were only 9, but the type was still in use as late as September 1918 (although still in single figures).
Engine: Mercedes D.III
Span: 27ft 10in upper, 26ft 3in lower
Length: 24ft 3in
Height: 9ft 8in
Empty weight: 1,530lb
Loaded weight: 2,032lb
Max speed: 102mph
Armament: Two synchronised 7.92mm LMG 08/15 Spandau machine guns