Rumpler 6B

The Rumpler 6B (formally known as the ED) was a German floatplane fighter designed during World War I by Rumpler Flugzeugwerke for the Imperial German Navy's (Kaiserliche Marine) Naval Air Service (Marine-Fliegerabteilung). It was a single-seat version of the Rumpler C.I reconnaissance biplane. Small numbers of aircraft were exported to Finland, the Austro-Hungarian and Ottoman Empires as well as the Kingdoms of Bulgaria and Romania.

Design and development
Born out of a requirement of the Kaiserliche Marine (Imperial Navy) for a seaplane fighter to defend its air bases issued in May 1916, the Rumpler 6B was, like its contemporaries the Albatros W.4 and Hansa-Brandenburg KDW, an adaptation of an existing landplane design. Unlike its competitors derived from single-seat fighters, Rumpler's new aircraft was based on the company's two-seat C.I reconnaissance aircraft. The 6B retained the C.I's robust wooden and fabric fuselage with a steel-tube framework reinforcing the forward fuselage, although the observer's cockpit was faired over. The installation of the water-cooled 160 hp Mercedes D.III engine remained the same with the radiator mounted to the underside of the upper wing and the "chimney" exhaust protruding above the level of the upper wing. The two-bay wings were unaltered although their stagger was revised with the upper wing moved forward to compensate for the removal of the observer, his armament and the weight of the two floats. These were connected to the fuselage by steel-tube V-struts. A larger rudder was fitted to offset the increased side area caused by the addition of floats. In the production aircraft, the area of the horizontal stabilizers was slightly reduced. The armament consisted of a fixed, forward-firing 7.92 mm (.312 in) LMG 08/15 "Spandau" machine gun.

The initial version of the fighter was the 6B1. A total of 39 of these were produced, with all but one of the number having been delivered by the end of May 1917. A new version of the basic design, the 6B2, was introduced in October 1917. These aircraft retained the D.III engine, but otherwise they were based on the C.IV, with larger dimensions and more rounded horizontal tail surfaces.

Operational history
The three 6B1 prototypes were delivered in July-August 1916 for evaluation. The first batch of 10 production aircraft were delivered between November 1916 and February 1917. A second batch of 25 6B1s were received between February and May, although one last aircraft was delivered in January 1918. The prototype 6B2 was tested beginning in January 1917 with 50 production models delivered by the Naval Air Service between October 1917 and January 1918.

The Rumpler 6Bs were mostly employed at German seaplane bases at Ostend and Zeebrugge. One of the 6B1 prototypes was sent to Zeebrugge in late August; it shot down a British Short floatplane on 31 August. The fighter intercepted and shot down a twin-engined British Caudron G.4 bomber returning from a bombing mission on [Sint-Denijs-Westrem Airfield]], Occupied Belgium, on 7 September. It intercepted a French FBA Type H flying boat on a reconnaissance mission on 23 October. The flying boat was forced to make an emergency landing and the crew was captured. More 6B1s were delivered in December.

Flugmeister Karl Meyer damaged a Sopwith Pup fighter of the Royal Naval Air Service on and forced it to make an emergency landing on the beach near Bredene, Occupied Belgium. Meyer taxiied up to the beach and took the pilot captive. A 6B1 was destroyed in a landing accident in Zeebrugge harbor on 1 March 1917; the pilot survived. Four 6B1s from Ostende covered the unsuccessful search for two missing torpedo boats on 21 March. The searchers spotted the British blimp C-17 on patrol near Nieuwpoort, Belgium, and radioed the spot report back to Zeebrugge where Meyer and another pilot took off to intercept it. They were successful and shot down the blimp, killing its crew. A 6B1 was used to rescue a wounded French pilot was from his shot-down FBA H-4 on 24 May. The following morning, three 6B1s from Ostende escorted 23 Gotha G.IV heavy bombers as they returned from bombing England.

Two were also sent to the Kingdom of Bulgaria and some to the Kingdom of Romania to fight the Russians. Two 6B1s were deployed the German-Turkish Naval Flying Unit (Wasserfliegerabteilung) in 1917. One pilot from this unit claimed to have shot down two aircraft that same year.

Use in Bulgaria
The two 6B1s that were stationed at the German Naval Air Station Peynerdjik near Varna were transferred in April 1918 to the Bulgarian Navy. They were destroyed in accordance with the clauses of the Treaty of Neuilly-sur-Seine in 1920.

Use in Finland
In February 1918, the Finnish White Army ordered one Rumpler and seven other aircraft from Germany. The aircraft was destroyed in an accident in October 1919. Another Rumpler aircraft was bought from the Germans in Tallinn in 1918 and it was used for seven years.

Survivors
The Hallinportti Aviation Museum has a partially restored Rumpler 6B2 on display.

Operators

 * Austro-Hungarian Empire
 * Austro-Hungarian Navy
 * 🇧🇬 Bulgaria
 * Bulgarian Navy
 * Finnish Air Force
 * German Empire
 * Imperial German Navy
 * 🇳🇱 Netherlands
 * Royal Netherlands Navy
 * Kingdom of Yugoslavia
 * Yugoslav Royal Navy
 * Yugoslav Royal Navy