View source for DFW R.II

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{|{{Infobox aircraft begin
 |name=R.II
 |image=File:Een Duitse DFW R.II (2157-111-021).jpg
 |caption=
}}{{Infobox aircraft type
 |type=Bomber
 |manufacturer=[[Deutsche Flugzeug-Werke|DFW]]
 |designer=
 |first flight=17 September 1917
 |introduced=
 |retired=
 |status=
 |primary user={{lang|de|[[Luftstreitkräfte]]}}
 |more users=
 |produced=
 |number built=3
 |variants with their own articles=
}}
|}

The '''DFW R.II''' (company designation '''T26 II''') was a [[heavy bomber]] ({{lang|de|Riesenflugzeug}}) aircraft designed by the {{lang|de|[[Deutsche Flugzeug-Werke]]}} (DFW) during the [[First World War]] for the [[Imperial German Army]]'s ({{lang|de|Deutsches Heer}}) [[Imperial German Air Service]] ({{lang|de|Luftstreitkräfte}}). Six aircraft were ordered in late 1916; of these three were completed, two were unfinished when the war ended in November 1918 and the last was cancelled. None of the aircraft flew any combat missions.

==Design and development==
The Imperial German Air Service wanted an improved version of the [[DFW R.I|R.I]] with a greater payload. The same arrangement of four [[inline engine (aviation)|inline engine]]s mounted in the [[fuselage]], driving two [[Tractor configuration|tractor propellers]] and two [[Pusher configuration|pusher propellers]] via long [[driveshaft]]s was used. Having learned from the experiences with the R.I, the engine mounts of the R.II were built from pressed steel integrated with the fuselage frames. The shorter [[crankshaft]]s of the {{convert|260|hp|lk=on|adj=on|sp=us}} [[Mercedes D.IVa]] [[straight-six engine|straight-six]] piston engines in the R.II did not cause any new problems, but the aircraft still had vibration problems. These were traced to the high rotational speeds of the driveshafts; they were enclosed within stiffener tubes with [[ball bearing]]s, which fixed the problem.<ref>Herris, pp. 228–229, 235</ref><ref>Haddow & Grosz, pp. 93–94</ref>

==Operational history==
Of the six ordered by the [[Luftstreitkräfte]], only three were completed before the end of the war. The first aircraft was delivered to the R-plane Training Unit ({{lang|de|Riesenflugzeugeersatzabteilung}}) at [[Cologne]] on 1 April 1918 where it flew training missions for the rest of the war because its performance, reliability and load-carrying capability were significantly inferior to the [[Zeppelin-Staaken]] aircraft like the [[Zeppelin-Staaken R.VI|R.VI]]. The second aircraft was ready for operational service in October and the third made its first flight on 22 July. Following the war, DFW planned to convert the two unfinished aircraft into [[airliner]]s which would have carried 24 passengers, but the aircraft were scrapped instead.<ref>Haddow & Grosz, pp. 94–96</ref>

==Specifications R.II (15/16)==
{{Aircraft specs
|ref=DFW Aircraft of WWI: A Centennial Perspective on Great War Airplanes;<ref>Herris, p. 214</ref> The German Giants: The German R-Planes 1914–1918<ref>Haddow & Grosz, p. 98</ref>
|prime units?=met
<!--
        General characteristics
-->
|genhide=

|crew=5
|length m=20.93
|length ft=
|length in=
|length note=
|span m=
|span ft=
|span in=
|span note=
|upper span m=35.06
|upper span ft=
|upper span in=
|upper span note=
|mid span m=
|mid span ft=
|mid span in=
|mid span note=
|lower span m=
|lower span ft=
|lower span in=
|lower span note=
|height m=6.4
|height ft=
|height in=
|height note=
|wing area sqm=266
|wing area sqft=
|wing area note=
|airfoil=
|empty weight kg=8634
|empty weight lb=
|empty weight note=
|gross weight kg=11693
|gross weight lb=
|gross weight note=
|max takeoff weight kg=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity={{convert|2450|l|impgal USgal}}
|more general=
<!--
        Powerplant
-->
|eng1 number=4
|eng1 name=[[Mercedes D.IVa]] 
|eng1 type=[[water-cooled]] [[straight-six engine|straight-six]] piston engines
|eng1 kw=<!-- prop engines -->
|eng1 hp=260<!-- prop engines -->
|eng1 note=
|power original=
|thrust original=
|more power=

|prop blade number=2
|prop name=
|prop dia m=3.5
|prop dia ft=<!-- propeller aircraft -->
|prop dia in=<!-- propeller aircraft -->
|prop note=

<!--
        Performance
-->
|perfhide=

|max speed kmh=135
|max speed mph=
|max speed kts=
|max speed note=
|max speed mach=<!-- supersonic aircraft -->
|cruise speed kmh=
|cruise speed mph=
|cruise speed kts=
|cruise speed note=
|range km=
|range miles=
|range nmi=
|range note=
|combat range km=
|combat range miles=
|combat range nmi=
|combat range note=
|ferry range km=
|ferry range miles=
|ferry range nmi=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=
|ceiling ft=
|ceiling note=
|climb rate ms=
|climb rate ftmin=
|climb rate note=
|time to altitude=58 minutes to {{cvt|2000|m}}
|wing loading kg/m2=44
|wing loading lb/sqft=
|wing loading note=
|power/mass=
|thrust/weight=

|more performance=
<!--
        Armament
-->
|armament=Positions for nose, ventral and dorsal gunners
}}

==See also==
{{aircontent
<!-- include as many lines are appropriate. additional lines/entries with carriage return. -->
|see also= 
|related=<!-- related developments -->
*[[DFW R.I]]
*[[DFW R.III]]
|similar aircraft=
*[[Bristol Braemar]]
|lists=
*[[List of World War I Central Powers aircraft#German Aircraft|List of World War I Central Powers aircraft, Germany]]}}

==Notes==
{{reflist|30em}}

==Bibliography==
* {{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|last=Haddow|first=G.W.|first2=Peter M. |last2=Grosz|title=The German Giants: The German R-Planes 1914-1918|publisher=Putnam|location=London|year=1988|edition=3rd|isbn=0-85177-812-7|name-list-style=amp}}
* {{cite book |last1=Herris |first1=Jack |title=DFW Aircraft of WWI: A Centennial Perspective on Great War Airplanes |date=2017 |isbn=978-1-935881-54-4 |publisher=Aeronaut Books |location=n.p. |series=Great War Aviation Centennial Series|volume=29}}

==External links==
{{commons category|DFW R.II}}
* "[http://www.flightglobal.com/PDFArchive/View/1919/1919%20-%201272.html The German D.F.W. Commercial Four-Engined Biplane]" ''Flight'' 25 September 1919, vol. XI, no. 39, pp.&nbsp;1274–78. <!--Describes and illustrates both the military R.II and the proposed airliner.-->

{{DFW aircraft}}
{{Idflieg R-class designations}}

[[Category:DFW aircraft|R.II]]
[[Category:1910s German bomber aircraft]]
[[Category:Four-engined push-pull aircraft]]
[[Category:Mid-engined aircraft]]
[[Category:Biplanes]]
[[Category:Aircraft first flown in 1918]]