Zeppelin-Staaken L

Zeppelin-Staaken

Company type	Manufacturer
Industry	Aerospace, Aircraft manufacturing
Founded	1914
Founder	Count Ferdinand von Zeppelin
Headquarters	Germany

Overview

The Zeppelin-Staaken L represented an experimental long-range maritime patrol floatplane developed during the First World War by the German manufacturer Zeppelin-Staaken for the Imperial German Navy's Naval Air Service (Marine-Fliegerabteilung). It was derived from the Zeppelin-Staaken R.VI heavy bomber and featured a large airframe powered by four engines arranged in paired tractor-pusher configurations situated between the wings. Designed to accommodate a crew of seven, only one prototype was constructed in 1917 for evaluation. This sole example was lost in a fatal crash in June 1918, resulting in no survivors.

Background and design

Following two years of wartime operations, the Naval Air Service identified the increasing risks faced by Zeppelin airships conducting reconnaissance over the North Sea. In late 1916, Rear Admiral (Konteradmiral) Otto Philipp, commander of the Naval Air Service, issued specifications calling for three categories of multi-engine seaplanes to supplant the Zeppelins. The highest priority was assigned to a four-engine maritime patrol aircraft capable of extended endurance—10 to 12 hours—and able to sustain flight on just two engines, as detailed in a memorandum dated 26 December. On 10 February 1917, Philipp further specified that this aircraft’s roles would include naval mine detection, anti-submarine operations, and maritime traffic control. Responding to these requirements, Zeppelin-Staaken—established in 1914 by Count Ferdinand von Zeppelin to produce long-range heavy bombers—proposed a floatplane adaptation of their R.VI bomber, enhanced with additional fuel capacity. The Naval Air Service approved the concept and commissioned a single unit on 15 February 1917.

The L's fuselage was constructed using a lattice framework composed of wood and steel tubing; its forward section was sheathed in plywood while fabric covered the remainder. The crew compartment contained positions for two pilots, a bombardier/navigator, a wireless operator, and a fuel attendant. At the nose sat the bombardier’s station equipped with a bombsight and provision for mounting a machine gun. Behind this area were gunner stations: a dorsal position armed with two flexible machine guns and a ventral position with one machine gun. Initially, the aircraft retained the R.VI’s conventional wheeled landing gear complemented by a twin-wheel auxiliary undercarriage beneath the nose to facilitate landings. However, upon delivery to the testing ground at Potsdam, these wheels were replaced by two large duralumin floats designed for water operations. Each float was internally divided into approximately twelve watertight compartments.

Structurally, the L was a four-bay biplane with its fuselage affixed to the lower wing. The wooden wings featured dual main spars and were assembled from three sections: a central panel flanked by two removable outer panels bolted on. Balanced aerodynamic counterbalanced ailerons were installed solely on the upper wing; unlike those on the R.VI, these extended beyond the wingtips. The wings exhibited a slight backward sweep of about 1.5 degrees. The empennage comprised a biplane tail assembly with two horizontal stabilizers and two balanced rudders. Initially, only struts connected the upper horizontal stabilizer to the fuselage, but during flight trials, an added vertical stabilizer with an extra rudder improved directional stability. Elevators spanned the full width of both horizontal stabilizers.

Power was supplied by four 260-horsepower (190 kW) Mercedes D.IVa straight-six engines mounted between the wings on A-shaped struts located above each float. Each pair was configured in a tractor-pusher arrangement housed within an aluminium nacelle mounted atop the crossbar of each strut—with one engine positioned at the front and its counterpart at the rear. Additional support struts extended from the lower wing to each nacelle to bear gearbox loads. Radiators were affixed above each nacelle on supporting struts for engine cooling. A flight mechanic’s cockpit was located within each nacelle between the paired engines. Initially equipped with four-bladed propellers on the rear engines, these were later replaced by two-bladed versions during testing.

Fuel storage included fourteen tanks totaling 245-litre (54 imp gal; 65 US gal) housed centrally within the fuselage, supplemented by two 150-litre (33 imp gal; 40 US gal) tanks inside each nacelle. Additionally, gravity-fed fuel tanks holding 155-litre (34 imp gal; 41 US gal) were installed beneath each upper wing above the nacelles to supply fuel without relying on pumps. These enhancements extended flight endurance to approximately ten hours—surpassing the R.VI bomber’s seven-hour range.

History

The Zeppelin-Staaken L was finalized in August 1917, with its floats attached prior to 5 September, the date when it conducted two brief flights on the Spree River. During taxiing tests, it became evident that the floats required extra strut reinforcement. On 12 November, the aircraft attempted a flight to the Naval Air Service base at Warnemünde, but an engine malfunction forced an emergency landing at Saaler Bodden, approximately 40 km (25 mi) away from the destination. After undergoing repairs over several days, the L was handed over to the Seaplane Experimental Command (Seeflugzeug-Versuchs-Kommando) on 17 November for evaluation. Due to its considerable size, none of the existing hangars could accommodate it, necessitating the construction of a dedicated hangar.

Testing revealed that once sufficient fuel had been used to allow flight on three engines, range could be further extended by shutting down one engine. Another conclusion from the trials was that the aircraft exhibited less stability on water compared to Zeppelin-Lindau flying boats such as the RS.III, designed by Claude Dornier. In December 1917 and January 1918, the Naval Air Service placed orders for six enhanced models designated as the Zeppelin-Staaken 8301, split into two batches. At the war’s conclusion, the first two ordered units were still undergoing testing by the Experimental Command; two from the subsequent batch had been completed but not yet delivered. On 3 June 1918, the L crashed near Warnemünde, resulting in total loss of life aboard, potentially caused by engine failure.