Fokker D.II
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{{Infobox aircraft
| name = Fokker D.II
| image = Fokker biplane (1916).jpg
| caption =
| type = Fighter
| manufacturer = Fokker-Flugzeugwerke
| designer = Martin Kreutzer
| first_flight = December 1915
| introduction =
| retired =
| status =
| primary_user =
| more_users =
| produced =
| number_built =
| variants =
}}
The Fokker D.II was a biplane fighter designed by the Fokker Aircraft Company ({{lang|de|Fokker-Flugzeugwerke}}) during the First World War for the Imperial German Army's ({{lang|de|Deutsches Heer}}) Imperial German Air Service ({{lang|de|Fliegertruppen des deutschen Kaiserreiches}}) and the Imperial and Royal Aviation Troops ({{lang|de|Kaiserliche und Königliche Luftfahrtruppen or K.u.K. Luftfahrtruppen}}) of the Austro-Hungarian Empire. Two prototypes designated by the factory as the M.17 were built in different configurations before the third one was accepted for production as the D.II. The Imperial German Air Service purchased 181 D.IIs, excluding the prototypes.
Background and development
By late 1915 Anthony Fokker had become aware that his monoplane fighters like the E.III were outclassed by faster British and French biplanes and he began development of a series of biplanes. He preferred to use a light-weight rotary engine, but he wanted to evaluate the impact of using a heavier, more powerful water-cooled engine. He was uncertain about the relative advantages of single-seat vs two-seat fighter and so decide to develop prototypes that would demonstrate the virtues and disadvantages of each of the four configurations. All of these aircraft were armed with a fixed 7.92 mm (.312 in) lMG 08/15 machine gun operated by the pilot. The M.17 was his single-seat design with a air-cooled {{cvt|80|hp|lk=on}} rotary engine.Leaman, pp. 58–59
File:Fokker M.17E jachtvliegtuig (2161 026076).jpg
The first prototype greatly resembled the first prototype of the M.16 with a fuselage that completely filled the space between the single-bay wings, but this also had the M.16's significant disadvantage of severely restricted visibility forward and downwards. The second prototype shared the single-bay wings with the earlier aircraft, but the fuselage was reduced in height so that the upper wing had to be supported on cabane struts to improve the pilot's view. Flight testing revealed that the fuselage was too short, the wingspan too great and the engine was too weak. The third prototype had a longer fuselage, slightly shorter wings and a more powerful 75 kW (100 hp) Oberursel U.I engine, with a new rudder. It was evaluated by the Imperial German Air Service in April 1916 and provisionally accepted for production as it was judged to be an improvement over the E.III. A contract for a dozen pre-production D.IIs was awarded in July and four batches for 169 production models were awarded through October.Harris, pp. 22, 31
Operational history
The D.IIs were used by the home-defense Kampfeinsitzerkommandos and the early Jagdstaffeln but were quickly replaced when the new Albatros, Roland D.I and Roland D.II fighters came out in late 1916.Herris, p. 31
Operators
;{{flag|Austro-Hungarian Empire}}
;{{flag|German Empire}}
;{{SUI}}
Specifications (D.II)
{{Aircraft specs
|ref=Fokker Aircraft of WWI: A Centennial Perspective on Great War Airplanes: Volume 1: Spinne – M.10 & Watercraft
|prime units? = met
|crew=one pilot
|length m=6.40
|length ft=21
|length in=0
|span m=8.75
|span ft=28
|span in=9
|height m=2.55
|height ft=8
|height in=4
|wing area sqm=18.0
|wing area sqft=194
|empty weight kg=384
|empty weight lb=847
|gross weight kg=575
|gross weight lb=1,268
|eng1 number=1
|eng1 name=Oberursel U.I rotary
|eng1 kw=75
|eng1 hp=100
|max speed kmh=150
|max speed mph=93
|range km=200
|range miles=124
|ceiling m=4,000
|ceiling ft=13,125
|climb rate ms=4.2
|climb rate ftmin=820
|wing loading kg/m2=31.0
|wing loading lb/sq ft=
|armament = *1 × fixed, forward-firing 7.92 mm (.312 in) lMG 08 machine gun
}}
{{aircontent
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Citations
{{Reflist}}
References
{{commons category|Fokker D.II}}
- {{cite book|author1-last=Gray|author1-first=Peter|title=German Aircraft of the First World War|orig-year=1970|year=1987 |publisher=Putnam |location=London|isbn=0-85177-809-7|edition=2nd|author2-first=Owen|author2-last=Thetford|name-list-style=amp}}
- {{cite book |author1-last= Green|author1-first= William |author2-last=Swanborough|author2-first=Gordon |title= The Complete Book of Fighters: An Illustrated Encyclopedia of Every Fighter Built and Flown |orig-year= 1994 |publisher= Salamander Books |location=London |isbn=1-84065-269-1|name-list-style=amp|year=2001 |edition=Revised and Updated}}
- {{cite book |last1=Grosz |first1=Peter Michael |last2=Haddow |first2=George |last3=Schiemer |first3=Peter |title=Austro-Hungarian Army Aircraft of World War One |date=1993 |publisher=Flying Machines Press |location=Mountain View, California |isbn=0-9637110-0-8|name-list-style=amp}}
- {{cite book |last1=Herris |first1=Jack|last2=Leckscheid|first2=Jörn |title=Fokker Aircraft of WWI: Volume 3: Early Biplane Fighters: A Centennial Perspective on Great War Airplanes |date=2021 |publisher=Aeronaut Books |location=n.p. |isbn=978-1-953201-05-8|series=Great War Aviation Centennial Series|volume=53|name-list-style=amp}}
- {{cite book |last1=Leaman |first1=Paul |title=Fokker Aircraft of World War One |date=2001 |publisher=Crowood Press |isbn=1-86126-353-8 |location=Marlborough, UK}}
{{Fokker aircraft}}
{{Idflieg D-class designations}}
{{World War I Aircraft of the Central Powers}}
Category:1910s German fighter aircraft