The Zeppelin-Staaken R.IV was a heavy bomber built in Germany in 1916 and which saw service during World War I, briefly on the Eastern Front and then more extensively on the Western Front until the end of the war. Built to the Imperial German Army's ("giant aircraft") specification, it was the first such design by Zeppelin-Staaken to receive the "R" designation.Gray & Thetford 1992, p.583
Design The R.IV was based on its VGO.I, VGO.II, and VGO.III predecessors.Haddow & Grosz 1988, p.231Herris 2020, p.80 It shared their wing design, albeit with the dihedral on the lower wing reduced from 3° to 1.5°.Haddow & Grosz 1988, p.233 Its biplane tail unit was similar to that of the VGO.II and VGO.III, but was raised so that the lower of the two horizontal stabilisers was mounted on top of the fuselage instead of beneath it.
Overall, it was a four-bay, equal-span biplane with slightly negative wing stagger.Haddow & Grosz 1988, p.213 Of mostly conventional configuration it diverged most noticeably from the designs of the day not only by its size, but by its biplane horizontal stabilisers, its two fins, and its tricycle undercarriage.Herris 2020, p.15 Its two pilots sat in an open cockpit.Haddow & Grosz 1988, p.212
It adopted the innovative coupled-engine design of the VGO.III, which featured pairs of engines combined by gearboxes and clutches. One pair, in the nose, drove a tractor propeller, and two pairs in nacelles in the interplane gaps drove pusher propellers. The power of each pair was combined by a gearbox and clutch to turn a single propeller, meaning that if one of the pair failed, it could be disengaged so that the surviving engine could continue to provide power.Haddow & Grosz 1988, p.226Herris 2020, p.64
The fuselage included a bomb bay large enough to carry a bomb. As defensive armament, the R.IV carried two machine guns in the fuselage, one firing upward and the other downward, plus a machine gun in the front of each engine nacelle. It also featured gunners' platforms on the top wing, above the engine nacelles. These were accessible in flight via a ladder and offered a 360° field of fire around the aircraft.
Development Like its predecessors, construction of the R.IV began at Versuchsbau Gotha-Ost (VGO), a division of Gothaer Waggonfabrik, in February 1916. However, during that year, production of airships by the Zeppelin company was relocated from Friedrichshafen to Staaken to distance the construction facilities from the increasing reach of strategic bombing by the Allies.Haddow & Grosz 1988, p.230 Its first flight was made on 16 August 1916. VGO personnel had begun to transfer to Staaken on 15 June, and by the time the R.IV had completed its test flights, the migration was complete. The aircraft was given the Idflieg serial R.12/15.
Operational history The R.IV was accepted by the Imperial German Army Air Service on 5 May 1917,Haddow & Grosz 1988, p.236Herris 2020, p.87 and on 12 June was assigned to Rfa 500 (, "giant aeroplane unit") at Auce. There, it participated in raids on Valmiera (28/29 June) and Saaremaa (8/9 July).
In late July, the aircraft was redeployed to Rfa 501 near Ghent. From there, until the end of the war, the R.IV dropped of bombs on London, Chelmsford, Thames Estuary, Calais, Morville, Boulogne, Étaples, Le Havre, Gravelines, Deauville, and Doullens. During a raid on London on the night of 16/17 February 1918, the R.IV survived a collision with a balloon apron stretched between the Woolwich Works and the West India Docks with only very minor damage.Haddow & Grosz 1988, p.31–32
The R.IV survived the war and was publicly displayed in Kassel and other German cities in 1919.
Operators Imperial German Army Air Service Rfa 500 Rfa 501
Specifications
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