O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Halberstadt D I
   Precursor of the later D II-III series machines, the Halberstadt D I appeared in February 1916. It displayed most of the characteristics perpetuated in the series machines; the delicate, angular, "all-moving" tail surfaces; the two-bay wings; in-line engine. It differed predominantly in having unstaggered wings and the radiators mounted on the fuselage sides. Although not confirmed, dimensional data applicable to D II-III was probably common also to the D I. Engine, 100 h.p. Mercedes D I. Armament, one Spandau machine-gun.

W.Green, G.Swanborough The Complete Book of Fighters

HALBERSTADT DI Germany

   In the late autumn of 1915, the Halberstadter Flugzeugwerke initiated flight testing of a single-seat fighter evolved by Dipl-Ing Karl Theis from the Halberstadt B II trainer. Apart from some structural reinforcement and the mounting of a single synchronised LMG 08/15 machine gun, the Halberstadt fighter differed from its progenitor primarily in having shorter-span, staggered wings. Two prototypes were built, one powered by a 120 hp Argus As II and the other by a 100 hp Mercedes D I. Both featured a neat, car-type frontal radiator which, it transpired, was to prove ineffectual in summer temperatures and was not to be perfected until 1918. These prototypes were at Adlershof in February 1916, the Mercedes-engined prototype undergoing static load testing, and, at this time, they were designated Halberstadt D I. An order for an initial batch of 12 D I fighters "powered by a 120 hp engine” was placed on 21 March 1916. In the event, the production model of the D I embodied a number of design refinements, and, with a 120 hp Mercedes D II engine, became the Halberstadt D II (which see). The following data relate to the 100 hp Mercedes-engined D I prototype.

Time to 3,280 ft (1 000 m), 4.5 min.
Empty weight, 1,215 lb (551 kg).
Loaded weight, 1,630 lb (739 kg).
Wing area, 258.34 sq ft (24, 00 m2).

J.Herris Halberstadt Aircraft of WWI. Volume 2: CL.IV-CLS.I & Fighters (A Centennial Perspective on Great War Airplanes 45)

Halberstadt Fighters

  By the middle of 1916, the French over Verdun and the British over the Somme had achieved air superiority over the German air service. The Fokker and Pfalz Eindeckers were too few in number and worse, were technically outmoded by new Allied fighters, the Nieuport 11 and D.H.2, that were faster in level flight and climb rate and were also more maneuverable. Leading German fighter pilots advocated development of new biplane fighters to redress the situation.
  The first new German fighter biplane to reach the front was the Halberstadt. We do not know what motivated Halberstadt, but their chief designer, Karl Theis, developed a biplane fighter from the Halberstadt B.II biplane trainer. This Halberstadt fighter prototype flew in the late Autumn of 1915. There were at least two prototypes. The first, the D.I (work number 155) was powered by a 100 hp Mercedes D.l engine, and experienced static-load testing on February 26, 1916 at Adlershof.
  The airframe achieved a load rating of 5.78 G, showing the robustness of the design.
  The second fighter prototype, designated D.III and powered by a 120 hp Argus As.II engine, appeared in the Frontbestand for February 1916 - the first biplane German fighter to reach the front. This delivery of a fighter prototype was likely for frontline evaluation.
  On March 8, 1916, Halberstadt received a letter of intent to produce "a dozen D.l fighters powered by a 120 hp engine based on the example demonstrated at Adlershof." Serial numbers D.100-111/16 were assigned. The contract was signed on March 21 and specified a useful load of 150 kg, including one synchronized machine gun with 500 rounds of ammunition, a top speed of 145 km/h, and climb to 4,000 meters in 40 minutes.
  When the first production Halberstadt fighters were test flown they easily exceeded the Idflieg requirements.


Halberstadt D.I

  The Halberstadt biplane fighter has the honor of being the first German fighter biplane to reach the front. Karl Theis, the chief designer of Halberstadt, developed a biplane fighter from the Halberstadt B.II biplane trainer. The first Halberstadt fighter prototype, the D.I (work number 155), was powered by a 100 hp Mercedes D.I engine and underwent static-load testing on February 26, 1916 at Adlershof. The sturdy airframe achieved a load rating of 5.78 G; the Halberstadt was a very robust aircraft that, as far as is known, never suffered a structural failure in combat.
  The second fighter prototype, designated D.III and powered by a 120 hp Argus As.II engine, appeared in the Frontbestand for February 1916 - the first biplane German fighter to reach the front. Apparently it was sent for front-line evaluation.
  On March 8, 1916, Halberstadt received a letter of intent to produce "a dozen D.I fighters powered by a 120 hp engine based on the example demonstrated at Adlershof." Serial numbers D.100-111/16 were assigned. The contract was signed on March 21.
  The prototypes handily exceeded the performance requirements. The D.I designation applied to production aircraft powered by a 100 hp Mercedes and appeared like D.I D.100/16 above. Compared to the prototypes the D.I had an airfoil, not frontal, radiator, horizontal exhaust pipe, and fully-faired turtle-deck behind the cockpit for improved streamlining. The D.I also had horn-balanced ailerons However, aside from a few early D.I aircraft, most production aircraft were powered by the 120 hp Mercedes.
  The Halberstadt D.I was tested with four anti-balloon rockets on each outboard interplane strut. However, they were very inaccurate and unreliable and potentially hazardous to the aircraft carrying them, so the rockets were dropped in October 1916.


Halberstadt Fighter Type Description
Type Engine Ailerons Wings Remarks
Prototype (1) 100 hp Mercedes D.I Plain ailerons Exhaust cut into wing leading edge Single fixed gun on port
D.I 100 hp Mercedes D.I Horn-balanced ailerons or unbalanced ailerons with trailing edge flush with wing trailing edge. Two-piece upper wing joined at centerline. Angular cut-out. Single fixed gun on starboard. Long exhaust on starboard.
Notes:
(1) Prototypes had frontal radiator and aileron cables over &. under wings. All others had airfoil radiators and production aircraft had aileron cables inside their lower wings.


Halberstadt Fighter Specifications
Spec \ Type D.l D.II D.III D.IV D.V
Engine 100 hp Mercedes D.l 120 hp Mercedes D.II 120 hp Argus As.II 150 hp Benz Bz.III 120 hp Argus As.II
Span, upper - 8.8 m 8.8 m 8.4 m 8.8 m
Span, lower - 7.92 m - - 7.8 m
Chord, upper - 1.52 m 1.52 m 1.5 m 1.5 m
Chord, lower - 1.52 m 1.52 m - 1.5 m
Wing Area 24.0 m2 23.6 m2 23.6 m2 24.0 m2 23.6 m2
Length - 7.3 m 7.3 m - 7.3 m
Weight empty 551 kg 520 kg 525 kg - 600 kg
Weight loaded 739 kg 730 kg - 815 kg 812 kg
Speed - - - - 160 km/h
Climb
1,000 minutes 4.5 3.5 4 - 4
2,000 minutes 10 8.5 9 - 9
3,000 minutes 18.5 14.5 15 - 15
4,000 minutes 35 22.5 - - 24
5,000 minutes - 38.5 - - -
D.II(Av) Empty Wt. 575 kg, Loaded Wt. 728 kg.
D.II(Han) Empty Wt. 561 kg, Loaded Wt. 744 kg


Halberstadt Fighter Production
Order Date Quantity Type Engine Serial Numbers & Notes
March 8, 1916 12 D.l D.II 100 hp Mercedes D.l
120 hp Mercedes D.II D.100-111/16