The Siemens-Schuckert R.VIII was a bomber aircraft designed and built in Germany from 1916.
Having cut their teeth with the Steffen R series, Siemens-Schuckert planned to produce a six engined Riesenflugzeug for the Military Air Service. In common with many of the other contemporary R projects the R.VIII had all six engines inside the fuselage, where they were tended by mechanics, driving two tractor and two pusher propellers, mounted between the mainplanes, via leather cone clutches combining gearboxes, shafts and bevel gearboxes. Two aircraft were built but only the first, R23/16, was completed. Ground trials commenced in 1919, after the armistice, but were interrupted by a gearbox failure which resulted in a propeller breaking up and causing extensive damage. The second airframe, R24/16 was never completed and the first not repaired after the ground running accident due to the Versaille Treaty restrictions. At the time of its completion the Siemens-Schuckert R.VIII was the largest complete aeroplane in the world, (the Mannesman-Poll triplane was to have been much bigger but was not completed before the Versaille Treaty restrictions were applied).