The Albatros D.I was a German fighter aircraft used during World War I. Although its operational career was short, it was the first of the Albatros D types which equipped the bulk of the German and Austrian fighter squadrons (Jagdstaffeln) for the last two years of the war.
The D.I was designed by Robert Thelen, R. Schubert and Gnädig, as an answer to the latest Allied fighters, such as the Nieuport 11 Bébé and the Airco D.H.2, which had proved superior to the Fokker Eindecker and other early German fighters, and established a general Allied air superiority. It was ordered in June 1916 and introduced into squadron service that August.1
The D.I used a paneled plywood semi-monocoque fuselage, which was lighter and stronger than the fabric-skinned box-type fuselage then in common use, as well being easier to give an aerodynamically clean shape. On the other hand it was less costly to manufacture than a "full monocoque" fuselage. It was powered by either a 110 kW (150 hp) Benz Bz.III or a 120 kW (160 hp) Mercedes D.III six-cylinder watercooled inline engine. The D.I thus became the most powerful fighter aircraft yet introduced by the Luftstreitkräfte. The additional power enabled twin fixed Spandau machineguns to be fitted without any loss in performance.
The D.I had a relatively high wing loading for its time, and was not particularly manoeuvrable. This was compensated by its superior speed and firepower, and it quickly proved the best all-round fighter available.
A total of 50 pre-series and series D.I aircraft were in service by November 1916, replacing the early Fokker and Halberstadt D types, giving real "teeth" to the Luftstreitkräfte's new Jagdstaffeln (fighter squadrons). Further production of D.Is was not undertaken, however; instead, a reduction in the gap between the top and bottom planes in order to improve the pilot's forward and upward vision resulted in the otherwise identical Albatros D.II, which became Albatros' first major production fighter.
The Albatros D.II was a modified version of the Albatros D.I. Pilots complained that the D.I offered poor visibility from the cockpit. To solve this problem, the D.IIs upper wing was brought closer to the fuselage. Mounted to the fuselage in front of the pilot, the D.IIs twin, synchronous machine guns set the standard for other German and Allied fighters. By the end of 1916, increased production of the Albatros gave Germany numerical superiority in the air war.
Albatros designers Thelen, Schubert and Gnädig produced the D.II in response to pilot complaints about poor upward vision in the Albatros D.I. The solution was to reposition the upper wing 36 cm (14 in) closer to the fuselage and stagger it forward slightly. Rearrangement of the cabane struts also improved forward view. The D.II otherwise retained the same fuselage, engine installation, and armament as the D.I. Basic performance was unchanged. Idflieg ordered an initial batch of 100 D.II aircraft in August 1916.
In November 1916, Idflieg banned Windhoff "ear" radiators in operational aircraft. This was due to the fact that the Windhoff-manufactured radiators were at a lower level than the crankcase of the engine they were cooling, and a shot into either radiator would likely drain the cooling system of coolant, resulting in engine failure. Late production D.IIs switched to using a Teves und Braun "airfoil shape" radiator in the center section of the upper wing.
D.IIs formed part of the initial equipment of Jagdstaffel 2, the first specialized fighter squadron in the German air service. Famous pilots included Oswald Boelcke and Manfred von Richthofen. With its high speed and heavy armament, the D.II won back air superiority from Allied fighter types such as the Airco DH.2 and Nieuport 11.
Albatros built 200 D.II aircraft. LVG (Luft-Verkehrs-Geselleschaft) produced another 75 under license. Service numbers peaked in January 1917, when 214 machines were in service. The D.II operated well into 1917. As late as 30 June 1917, 72 aircraft were in the frontline inventory, and even in November 11 D.IIs and 9 D.Is were still in service, alongside the by now far more numerous D.IIIs and D.Vs.
Oeffag (Oesterreichische Flugzeugfabrik AG) also built the D.II under license for the Luftfahrtruppen. The Austrian machines used a 138 kW (185 hp) Austro-Daimler engine, and were fitted with a Teves und Braun-style wing mounted radiator. Oeffag produced only 16 examples before production shifted to the Albatros D.III.
The Albatros D.III was a biplane fighter aircraft used by the Imperial German Army Air Service (Luftstreitkräfte) and the Austro-Hungarian Air Service (Luftfahrtruppen) during World War I. The D.III was flown by many top German aces, including Manfred von Richthofen, Ernst Udet, Erich Löwenhardt, Kurt Wolff, and Karl Emil Schäfer. It was the preeminent fighter during the period of German aerial dominance known as "Bloody April" 1917.
Work on the prototype D.III started in late July or early August 1916. The date of the maiden flight is unknown, but is believed to have occurred in late August or early September. Following on the successful Albatros D.I and D.II series, the D.III utilized the same semi-monocoque, plywood-skinned fuselage. At the request of the Idflieg (Inspectorate of Flying Troops), however, the D.III adopted a sesquiplane wing arrangement broadly similar to the French Nieuport 11. The upper wing was extended while the lower wing was redesigned with reduced chord and a single main spar. "V" shaped interplane struts replaced the previous parallel struts. For this reason, British aircrews commonly referred to the D.III as the "V-strutter."
After a Typenprüfung (official type test) on 26 September 1916, Albatros received an order for 400 D.III aircraft, the largest German production contract to date. Idflieg placed additional orders for 50 aircraft in February and March 1917.
The D.III entered squadron service in December 1916, and was immediately acclaimed by German aircrews for its maneuverability and rate of climb. Two faults with the new aircraft were soon identified. Like the D.II, early D.IIIs featured a Teves und Braun airfoil shaped radiator in the center of the upper wing, where it tended to scald the pilot if punctured. From the 290th D.III onward, the radiator was offset to the right.
More seriously, the new aircraft immediately began experiencing failures of the lower wing ribs and leading edge. On 23 January 1917, a Jasta 6 pilot suffered a failure of the lower right wing spar. On the following day, Manfred von Richthofen suffered a crack in the lower wing of his new D.III. On 27 January, the Kogenluft (Kommandierenden General der Luftstreitkräfte) issued an order grounding all D.IIIs pending resolution of the wing failure problem. On 19 February, after Albatros introduced a reinforced lower wing, the Kogenluft rescinded the grounding order. New production D.IIIs were completed with the strengthened wing while operational D.IIIs were withdrawn to Armee-Flugparks for modifications, forcing Jastas to use the Albatros D.II and Halberstadt D.II during the interim.
At the time, the continued wing failures were attributed to poor workmanship and materials at the Johannisthal factory. In fact, the cause of the wing failures lay in the sesquiplane arrangement taken from the Nieuport. While the lower wing had sufficient strength in static tests, it was subsequently determined that the main spar was located too far aft, causing the wing to twist under aerodynamic loads. Pilots were therefore advised not to perform steep or prolonged dives in the D.III. This design flaw persisted despite attempts to rectify the problem in the D.III and succeeding D.V.
Apart from its structural deficiencies, the D.III was considered pleasant and easy to fly, if somewhat heavy on the controls. The sesquiplane arrangement offered improved climb, maneuverability, and downward visibility compared to the preceding D.II. Like most contemporary aircraft, the D.III was prone to spinning, but recovery was straightforward.
Albatros built approximately 500 D.III aircraft at its Johannisthal factory. In the spring of 1917, D.III production shifted to Albatros' subsidiary, Ostdeutsche Albatros Werke (OAW), to permit Albatros to concentrate on development and production of the D.V. Between April and August 1917, Idflieg issued five separate orders for a total of 840 D.IIIs. The OAW variant underwent its Typenprüfung in June 1916. Production commenced at the Schneidemühl factory in June and continued through December 1917. OAW aircraft were distinguishable by their larger, rounded rudders.
Peak service was in November 1917, with 446 aircraft on the Western Front. The D.III did not disappear with the end of production, however. It remained in frontline service well into 1918. As of 31 August 1918, 54 D.III aircraft remained on the Western Front.
The Fokker B.II designation was shared by two different unarmed German observation aircraft of World War I. One was developed from the same M.17 prototype that had been developed into the Fokker D.II fighter, and the other from the M.10. Both machines had a crew of two and resembled the B.I.
The Fokker D.I (company designation M.18) was a development of the D.II fighter. The D.I was also flown in Austro-Hungarian service as a reconnaissance aircraft under the designation B.III. Confusing the matter further, both the D.II and D.I arrived at the Front in German service at similar times, in July-August 1916. The main designer was Martin Kreutzer.
Similar to the D.II, the D.I was an unstaggered single-bay equal-span biplane. The upper fuselage was parallel with the upper wing. Unlike the D.II, the D.I was fitted with the 100 hp (75 kW) Mercedes D.I six cylinder water-cooled engine.
Control was achieved using wing-warping. The wings were also tested in twin bay form. To improve visibility, the center section was cut into and the wings were slightly staggered.
These improvements were retained, and the airplane was ordered into production with a 89 kW (120 hp) Mercedes D.II inline engine and a single synchronized 0.312 in (7.92 mm) LMG 08/15 machine gun. The Austro-Hungarian B.IIIs retained the D.I engine, and were armed with a 0.312 in (7.92 mm) Schwarzlose machine gun.
Deliveries began in July 1916. 90 were delivered to the German Fliegertruppen, and 16 to the Austro-Hungarian Luftfahrttruppen (as the B III). Eight were license produced by the Magyar Általános Gépgyár in Hungary.
One Austro-Hungarian B III was experimentally fitted with a 119 kW (160 hp) Mercedes D.III engine. Another had ailerons instead of wing warping, and still another had long span, swept back wings.
Compared with aircraft in service at that time, such as the Albatros D.II and the Nieuport 11, this Fokker's design and performance were decidedly unimpressive, and further production did not take place.
The D.I was the basis for the D.III and D.IV.
The Fokker D.II was a German fighter biplane of World War I. It was a single seat fighter aircraft developed before the Fokker D.I. It was based on the M.17 prototype, with single-bay unstaggered wings and a larger fuselage and shorter span than production D.IIs. Using a 75 kW (100 hp) Oberursel U.I, the D.II was underpowered, though the single 7.92 mm (.312 in) LMG 08/15 machine gun was normal for 1916. The German Army purchased 177.
In service, the D.II proved to be little better than the earlier Fokker Eindecker fighters - in particular, it was outclassed by the superior French Nieuport 11 and 17. Several Fokker D.IIs were used by the Kampfeinsitzerkommandos and the early Jagdstaffeln alongside the Halberstadt D.II but the early Fokker biplanes were quickly discarded when the new Albatros fighters came out.
The Fokker D.III (Fokker designation M.19) was a German single-seat fighter aircraft of World War I.
The M.19 began as an effort to improve the performance of the Fokker D.II (Fokker designation M.17). The M.19 featured the Oberursel U.III 14-cylinder, two-row rotary engine, combined with the two-bay wing cellule of the Fokker D.I. The U.III engine, first used in the Fokker E.IV, required a revised fore-and-aft mount and a strengthened fuselage. The prototype M.19 arrived at Adlershof for testing on 20 July 1916. Idflieg issued a production order for 50 aircraft at that time, followed by orders for an additional 60 aircraft in August and 100 in November. The new aircraft was designated D.III by Idflieg.
The first seven production aircraft were delivered on 1 September 1916. On that date, two D.III aircraft were ferried from Armee Flug Park 1 to Jagdstaffel 2 at Bertincourt. Oswald Boelcke received serial 352/16 and obtained seven victories in it between 2 September and 15 September.
While the D.III offered better performance than the D.I and D.II, Boelcke nevertheless found the D.III to be too slow. The D.III was plagued by its U.III engine, which wore out quickly and was difficult to manufacture. Low compression resulted in poor performance at altitude and cooling of the rear row of cylinders proved problematic. Moreover, the D.III offered indifferent maneuverability. On Boelcke's recommendation, the D.III was withdrawn from heavily contested sectors of the Western Front, but it continued to serve in quieter sectors.
In early October 1916, evaluation of Fokker's M.21 prototype at Adlershof revealed poor construction and workmanship. In response, Idflieg directed that a production D.III be tested for quality control purposes. In November 1916, serial 369/16 was disassembled and tested to destruction at Adlershof. While the wings proved acceptable, the fuselage and tail surfaces failed to meet specifications. Idflieg reprimanded Fokker for his firm's substandard construction practices, but permitted D.III production to continue. The Kogenluft, however, forbade the use of Fokker aircraft for frontline duties.
Fokker built 210 D.III aircraft at its Schwerin factory before production ceased in the spring of 1917. Late production aircraft replaced the wing-warping system with horn-balanced ailerons on the upper wing. Though unsuitable for frontline service, the D.III continued to serve in home defense units until late 1917. In October 1917, Germany supplied 10 D.IIIs to the Netherlands. These aircraft remained in service with the Luchtvaartafdeling until 1921.
Boelcke's D.III, serial 352/16, survived the war to be displayed at the Zeughaus museum in Berlin. The aircraft was destroyed by an Allied bombing raid in 1943.
The Fokker D.IV was a German fighter biplane of World War I, this was the last variant in the development of the D.I. In the quest for improved performance it was fitted with the more powerful Mercedes D.III inline six-cylinder water-cooled engine, generating 160 hp (120 kW). The aircraft was fitted with twin fixed, forward-firing synchronised 0.312 in (7.92 mm) LMG 08/15 "Spandau" machine guns. The upper wing was raised and the wing struts were strengthed by bracings configured in an N-pattern.
The aircraft was purchased in small numbers (40) by the German Army and the Swedes bought 4. The D.IV production life did not last long. It was soon superceded by newer and better designs. This type was soon overshadowed in 1917 by the higher performance D.VI and the iconic Fokker Dr.I triplane.
The Halberstadt D.II was not a particularly well received biplane fighter aircraft that served through the period of Allied air superiority in early 1916, but had begun to be replaced with the superior Albatros fighters by the autumn of that year. The Halberstadt D.II was underpowered, slow, lacking in firepower. It was unable to match the altitudes reached by other planes in the German arsenal.
If the only performance figures available for the type are accurate, the Halberstadt fighter's speed and climb were little better than the Eindecker's, and inferior to such Allied contemporaries as the Nieuport 11 and the D.H.2, but it earned the respect of Allied fighter pilots, and was the preferred mount of the pilots of the early Jagdstaffeln, until the Albatros D.I became available.
The D.II was the production version of the experimental D.I. Lightened to improve performance, it also featured staggered wings, and 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 that later used by the Albatros D.III and D.V. The two bay wings were very strongly braced, and the cockpit was raised in relation to where it had been on the D.I. This required a turtledeck to be built up on the rear fuselage to fair the cockpit into the lines of the fuselage. The wing trailing edge was a wooden member, as opposed to the wire common on contemporary German aircraft. Lateral control was by ailerons, but there were no fixed tail surfaces, and over-sensitive "Morane"-style balanced elevators similar to those employed by the Fokker Eindecker were retained. Although it must have shared the typical "Morane" elevator sensitivity, and the controls cannot have been well harmonised, it was very manoeuvrable in skilled hands, and could be dived safely at high speed. A single synchronised 7.92 mm (.312 in) lMG 08 "Spandau" machine gun fired through the propeller arc.
The D.II was a single-seat escort fighter, based on the structural principles of the C II, a wooden veneer shell fuselage. The deep fuselage filled to gap between the biplane wings completely. The production was hampered by a fire in the L.F.G. factory; about 20 were built. The Roland D.II suffered from a design flaw that limited the forward view of the pilot.
The LFG Roland D.III was a fighter aircraft produced in Germany during World War I. It was a further development of the D.I fighter, itself derived from the C.II reconnaissance aircraft. These machines had a fuselage that completely filled the interplane gap, a design feature intended to improve aerodynamics. However, it also resulted in limiting the pilot's field of vision in the down and forward direction, leading to complaints. LFG attempted to remedy this in the D.III design by introducing a gap between the upper fuselage and the upper wing, braced by cabane struts. The size of the tailplane was also increased.
While this did indeed result in an improvement over the Roland D.II that had preceded it, the performance of the D.III was inferior to that of other contemporary fighters available to the German Army, in particular those produced by Albatros, and the aircraft was therefore only produced in small quantities.
A number of captured Nieuport 17 fighters were given to German aircraft manufacturers to study, the Siemens-Schukert Werke produced the D.I based on the captured fighter. The D.I was a biplane powered by 110 hp (82 kW) Siemens-Halske Sh.I rotary engine. An order for 150 aircraft for the Imperial German Army Air Service was placed, but these were delayed by late delivery of the complicated geared engine, so that the aircraft was outclassed in combat by newer Allied aircraft when delivered. Only 95 aircraft were produced, most of which were used for training.
A single D.Ia was produced with a greater wing area and more powerful engine but was not ordered into production. The development continued through a prototype D.II to the D.III.