__NOTOC__ <!-- This article is a part of Wikipedia:WikiProject Aircraft. Please see Wikipedia:WikiProject Aircraft/page content for recommended layout. --> {{Infobox aircraft | name = R.I | logo = | logo_size = | image = | alt = | caption = | long_caption = | other_names = | aircraft_type = Bomber | aim = | outcome = | related = | national_origin = | manufacturer = DFW | design_group = | designer = | builder = | issuer = | status = | owners = | primary_user = ''Luftstreitkräfte'' | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = 1 | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = | retired = | first_flight = 5 September 1916 | initiated = | in_service = | last_flight = | expected = | developed_from = | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = }}

The '''DFW R.I''' (company designation '''T26''') 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}}). One bomber was built and it only flew two combat missions as it was destroyed after making an emergency landing in 1917.

==Development== Designed by Hermann Dorner, chief engineer of DFW, it was a large biplane of conventional configuration with four {{convert|220|hp|lk=on|adj=on|sp=us}} water-cooled Mercedes D.IV straight-eight piston engines mounted inside the fuselage. Each engine was provided with a gearbox and clutch, that drove the two-bladed wooden propellers on the wings via driveshafts; two of these were mounted tractor-fashion on the leading edge of the upper wing, and two mounted pusher-fashion on the trailing edge of the lower wing. The DFW heavy bombers were unique among the {{lang|de|Riesenflugzeuge}}, in that each engine drove a separate propeller and was not connected to the other engines or propellers.<ref name="Haddow">Haddow & Grosz, pp. 88–89</ref>

After factory tests proved promising, military acceptance trials commenced on 19 October 1916. Soon thereafter trouble set in, with the long crankshafts of the D.IV engines repeatedly failing. The cause was determined to be excessive vibrations from the lightly built engine mounts, but new engine mountings were installed and universal joints for the drive shafts were fitted to mitigate the problem, along with extended wings and other improvements.<ref name="Haddow"/>

==Operational history== Following these modifications, R.I (R 11/15) was deployed on the Eastern front with Rfa 500 at Alt-Auz, April to September 1917, from whence it bombed Schlok (now Sloka, Latvia), on 13 June. On its second combat mission in September, the R.I was forced to turn back before delivering its bombs due to the failure of two engines; after making a successful emergency landing it was destroyed when it ran into a trench and caught fire, killing one crewman.<ref>Haddow & Grosz, pp. 90, 92</ref><ref>Herris, pp. 218–219</ref> <!-- ==Variants== --> <!-- ==Units using this aircraft/Operators (choose)== -->

==Specifications (DFW R.I (second version))== {{Aircraft specs |ref=The German Giants: The German R-Planes 1914–1918;<ref>Haddow & Grosz, p. 92</ref> DFW Aircraft of WWI: A Centennial Perspective on Great War Airplanes<ref>Herris, p. 214</ref> |prime units?=met <!-- General characteristics --> |genhide=

|crew=at least 5 |length m=17.6 |length ft= |length in= |length note= |span m=30.5 |span ft= |span in= |span note= |height m=6 |height ft= |height in= |height note= |wing area sqm=186 |wing area sqft= |wing area note= |airfoil= |empty weight kg=6,800 |empty weight lb= |empty weight note= |gross weight kg=9,400 |gross weight lb= |gross weight note= |max takeoff weight kg= |max takeoff weight lb= |max takeoff weight note= |fuel capacity= |more general= <!-- Powerplant --> |eng1 number=4 |eng1 name=Mercedes D.IV |eng1 type=water-cooled straight-eight piston engines |eng1 kw=<!-- prop engines --> |eng1 hp=<!-- prop engines -->220 |eng1 note= |power original= |more power=

|prop blade number=4 × 2<!-- propeller aircraft --> |prop name= |prop dia m=<!-- propeller aircraft --> |prop dia ft=<!-- propeller aircraft --> |prop dia in=<!-- propeller aircraft --> |prop note= <!-- Performance --> |perfhide=

|max speed kmh=120 |max speed mph= |max speed kts= |max 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= |wing loading kg/m2=51.7 |wing loading lb/sqft= |wing loading note=

|power/mass= |thrust/weight=

|more performance= <!-- Armament --> |guns= Provision for dorsal, ventral and nose machine-gun positions |bombs= {{cvt|680|kg}} }}

==See also== {{aircontent <!-- include as many lines are appropriate. additional lines/entries with carriage return. --> |see also= |related= * DFW R.II

|similar aircraft= * AEG R.I * Linke-Hofmann R.I |lists=<!-- related lists --> }}

==References== {{reflist}}

==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== * "[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. The R.I is only mentioned on p.&nbsp;1274 and is not illustrated.

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

Category:1910s German bomber aircraft R.I Category:Four-engined push-pull aircraft Category:Mid-engined aircraft Category:Biplanes Category:Aircraft first flown in 1916