A.Kay Junkers Aircraft and Engines 1913-1945 (Putnam)

Junkers J11 (CLS1)

  The J11 was a floatplane version of the J10 for use as a two-seat, maritime patrol aircraft for the German Navy. It began with the modification of two J10s (c/ns 7501 and 7503) of corrugated Duralumin construction. Their rear fuselages were altered, their wing area was increased, a triangular tailfin was added and rudimentary, braced floats were fitted. The J11 was armed with a machine gun on either side of the cockpit and was powered by a Benz Bz IIIa 180hp engine. Only three were built, the first (7501/18) making its initial flight on 23 October 1918 piloted by Navy pilot Richard Thiedemann. The war’s end brought about a closure to the programme.


Data: Span 12.75m (41ft 10in); length 8.8m (28ft 10 1/2in); wing area 26.6m2 (286 sq ft); empty weight 915kg (2,018lb); loaded weight 1,420kg (3,131lb); max. speed 180kph (112mph); range 500km (310 miles).

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

Junkers J 11 (CLS I)
   Three machines (Nos. 7501-7503) which were literally seaplane versions of the CL I were delivered to the German Navy during 1918. Apart from the addition of a vertical fin to compensate the additional side area of the floats, the aircraft differed little from its landplane counterpart (apart from the obvious float chassis), although it was marginally larger in dimension. The tail surfaces were never really satisfactory, and after the war a completely new empennage was designed, when the type was used for civil purposes. Engine, 200 h.p. Benz. Span, 12.75 m. (41 ft. 10 in.). Length, 8.95 m. (29 ft. 4 3/8 in.). Height, 2.95 m. (9 ft. 8 1/8 in.). Weights: Empty, 914 kg. (2,011 lb.). Loaded, 1,420 kg. (3,124 lb.). Speed, 180 km.hr. (112.5 m.p.h.). Armament, twin Spandau and one Parabellum machineguns.

J.Herris German Seaplane Fighters of WWI (A Centennial Perspective on Great War Airplanes 2)

Junkers CLS.I

   A more serious competitor was the all-metal Junkers with factory designation J11, military designation CLS.I, a floatplane development of the Junkers CL.I two-seat fighter. A fixed fin was added to compensate for the side area of the floats in front of the center of gravity, but insufficient stability required modifications that continued even after the war, when the type was modified for civil use. The all-metal structure resisted the maritime environment better than did wood structures like those of the Brandenburgs, but the type was too late for wartime service.