The Zeppelin-Staaken R.VI was a four-engined German biplane strategic bomber of World War I, and the only Riesenflugzeug ("giant aircraft") design built in any quantity.

[1] In September 1914, at the start of World War I, Ferdinand von Zeppelin visualised the concept of a Riesenflugzeug (R) bomber, to be larger than the then-nascent Friedel-Ursinus twin-engined military aircraft.

Using engineers from the Robert Bosch GmbH, he created the Versuchsbau Gotha-Ost (VGO) consortium in a rented hangar at the Gotha factory.

The first Riesenflugzeug built was the VGO.I flying in April 1915, using three engines; two pusher and one tractor, with a 42.2 metres (138 feet 5 inches) span, four-bay interplane strut layout for its slightly swept-back leading edge biplane configuration, maintained throughout the entire Zeppelin-Staaken R-series of aircraft during World War I.

The VGO.I was built for the Marine-Fliegerabteilung (Imperial German naval Air service) and served on the Eastern Front[2] Later modified with two extra engines, it crashed during tests at Staaken.

The successor to the VGO III became the Staaken R.IV (IdFlieg number R.12/15), the only "one-off" Zeppelin-Staaken R-type to survive World War I, powered by a total of six engines, driving three propellers: a tractor configuration system in the nose and two pusher-mount nacelle mounts between the wings.

The R.VI required a complex 18-wheel undercarriage consisting of twin nosewheels and a quartet of four-wheeled groupings for its main gear to support its weight, and carried two mechanics in flight, seated between the engines in open niches cut in the center of each nacelle.

The Type 8301, of which four were ordered and three delivered, was developed from the R.VI by elevating the fuselage above the lower wing for greater water clearance, eliminating the bomb bays, and enclosing the open gun position on the nose.

Aircraft flew individually to their targets on moonlit nights, requesting directional bearings by radio after takeoff, then using the River Thames as a navigational landmark.

None were lost in combat over Great Britain (compared to 28 Gotha G bombers shot down over England), but two crashed returning to base in the dark.

[1] Very little remains of these giant bombers, although nearly a century after the end of World War I amateur historians of the "Poelcapelle 1917 Association vzw" working in Poelkapelle, northeast of Ypres, identified a wreck that was found in 1981 by Daniel Parrein, a local farmer who was plowing his land.

For a while it was thought that the wreck was that of French ace Georges Guynemer's SPAD S.XIII; however that was discounted when repair tools were found at the site, and further research pointed that the engine was a Mercedes D.IVa, possibly of a Gotha G bomber.

With the help of the Polish aviation historians, parts were identified as those of Zeppelin-Staaken R.VI R.34/16, which crashed on 21 April 1918 after a mission against the Royal Air Force airfield at Saint-Omer, France.

Eighteen R.VIs were built serialled 'R25' to 'R39' and 'R52' to 'R54' all except 'R30', which was used exclusively as a supercharged engine test-bed, saw service in the Luftstreitkräfte with Rfa500 and Rfa 501 on the western front stationed in the Ghent area.

[1] Data from The German Giants[1]General characteristics Performance Armament Zeppelin-Staaken Riesenflugzeuge Related development Aircraft of comparable role, configuration, and era