Zeppelin-Staaken R.VI - Design and Development

Design and Development

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 Gotha G. Using engineers from the Robert Bosch GmbH, he created the Versuchsbau Gotha-Ost (VGO) consortium in a rented hangar at the Gotha factory. Alexander Baumann became his chief engineer, although later the team included other noted engineers including Zeppelin's associate Claudius Dornier, Hugo Junkers and Baumann's protogé Adolph Rohrbach. Almost all of these Zeppelin-Staaken Riesenflugzeug designs used some variation of either pusher configuration and/or push-pull configuration in their engine layout, orientation and placement of their powerplants.

The first Riesenflugzeug built was the VGO.I flying in April 1915, using three engines; two pusher and one tractor. This was built for the Marine-Fliegerabteilung (Imperial German naval Air service) and served on the Eastern Front Later modified with two extra engines, it crashed during tests at Staaken. A similar machine, the VGO.II was also used on the Eastern Front.

Baumann was an early expert in light-weight construction techniques and placed the four engines in nacelles mounted between the upper and lower wing decks to distribute the loads to save weight in the wing spars.

The next aircraft, the VGO.III was a six-engined design The 160 hp Maybach engines were paired to drive the three propellers. It served with Riesenflugzeug Abteilung (Rfa) 500.

In 1916 VGO moved to the Berlin suburb of Staaken, to take advantage of the vast Zeppelin sheds there. 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. By the autumn of 1916, Staaken was completing its R.V, R.VI, and R.VII versions of the same design, and Idflieg selected the R.VI for series production over the 6-engined R.IV and other R-plane designs, primarily those of Siemens-Schuckertwerke AG.

With four direct-drive engines in a tandem push-pull arrangement, and a fully enclosed cockpit, the R.VI design required none of the complex gearboxes of other R-types. Each R.VI bomber cost 557,000 marks and required the support of a 50-man ground crew. The R.VI required a complex 18-wheel undercarriage 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 bombs were carried in an internal bomb bay located under the central fuel tanks, with three racks each capable of holding seven bombs. The R.VI was capable of carrying the 1000 kg PuW bomb.

Although designed by Versuchsbau, because of the scope of the project, the production R.VI's were manufactured by other firms: seven by Schütte-Lanz using sheds at Flugzeugwerft GmbH Staaken, Berlin; six by Automobil und Aviatik A.G. (Aviatik) (the original order was for three); and three by Albatros Flugzeugwerke. 13 of the production models were commissioned into service before the armistice and saw action.

One R.VI was as a float-equipped seaplane for the Marine-Fliegerabteilung (Imperial German Naval Air Service), with the designation Type L and s/n 1432, using Maybach engines. After the first flight on 5 September 1917 the Type "L" crashed during testing on June 3, 1918. 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.

R.VI serial number R.30/16 was the earliest known supercharged aircraft to fly, with a fifth engine - a Mercedes D.II - installed in the central fuselage, driving a Brown-Boveri four-stage supercharger at some 6,000 rpm. This enabled the R.30/16 to climb to an altitude of 19,100 feet (5,800 m). The idea of supercharging an aircraft's propeller-driving piston engines with an extra powerplant used solely to power a supercharger was not attempted again until later in World War II, when the Henschel Hs 130E revived the idea as the Höhen-Zentrale-Anlage system. The R.30/16 aircraft was later fitted with four examples of one of the first forms of variable-pitch propellers, believed to have been ground-adjustable only.