O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Rumpler 4B 11
   Virtually a 4A 13 type land machine mounted on a float chassis and used during 1914 for reconnaissance work. The ungainly size and pontoon shape of the floats may be noted. Aircraft of this type were allocated Navy Numbers 49-51 and 86-90. Engine, 100 h.p. Benz Bz I. Span, 13.0 m. (42 ft. 7 7/8 in.). Length, 9.8 m. (32 ft. 1 7/8 in.). Height, 3.52 m. (11 ft. 6 5/8 in.) Weights: Empty, 810 kg. (1,782 lb.). Loaded, 1,030 kg. (2,266 lb.). Sped, 130 km.hr. (81.25 m.p.h.).

Rumpler 4B 12
   A development of the 4B 11 and a seaplane version of the 4A 14. Some eighteen of these aircraft were built and in use in 1915, mainly on reconnaissance and coastal patrol. Navy Numbers: 101-110, 241-243 and 436-440. Engine, 150 h.p. Benz Bz III. Span, 14.5 m. (47 ft. 7 in.). Length, 9.6 m. (31 ft. 6 in.). Height, 3.6 m. (11 ft. 9 3/4 in.). Weights: Empty, 960 kg. (2,112 lb.). Loaded, 1,280 kg. (2,816 lb.).
   Rumpler 4B 13 was the same aircraft but powered with 160 h.p. Gnome rotary.

J.Herris Rumpler Aircraft of WWI (A Centennial Perspective on Great War Airplanes 11)

Early Rumpler Seaplanes
  
   Starting in 1914 Rumpler developed a flying boat that remained a single prototype and a small series of floatplanes developed from the Rumpler 4A13, itself a more powerful development of the Rumpler B.I unarmed two-seat trainer and reconnaissance airplane.
   As was typical of German naval aircraft, there were a number of variations on the basic design with limited production. As the war progressed Rumpler focused on two-seat reconnaissance airplanes for the Army, which purchased almost 20 times more airplanes than the Navy.

Rumpler 4B11, 4B12, & 4B13

   The Rumpler 4B11 and 4B12 were two-seat reconnaissance and training floatplanes based on the Rumpler 4A13 landplane. Both were built in very small numbers for the Navy. The 4B11 was powered by a 100 hp Mercedes D.I. The 4B12 had the more powerful 150 hp Benz Bz.III. The 4B13 was similar except powered by a 160 hp Gnome rotary engine. All three types were conventional wood, wire, and fabric designs typical of their era.


Rumpler 4B Production
Type Qty Marine Numbers
4B11 7 49, 64, 86-90
4B12 31 51, 101-110, 241-253, 436-442
4B13 1 50