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

Brandenburg W 26
   Designed as a long-range two-seat, patrol seaplane with an endurance of up to eight hours, three W 26s were constructed, Nos. 1739-1741. It was a large machine and seems to have owed something to the Friedrichshafen seaplanes in appearance. Both transmitting and receiving radio apparatus was carried. Engine, 260 h.p. Mercedes, D IVa. Span, 18.8 in. (61 ft. 8 1/4 in.). Length, 13.015 m. (42 ft. 8 3/8 in.). Area, 86.3 sq.m. (932 sq.ft.). Weights: Empty, 1,675 kg. (3,685 lb.). Loaded, 2,490 kg. (5,478 lb.). Speed, 135 km.hr. (84.35 m.p.h.). Duration, 8 hr. Armament, one Parabellum and one or two Spandau machine-guns.

C.Owers Hansa-Brandenburg Aircraft of WWI Vol.2: Biplane Seaplanes (A Centennial Perspective on Great War Airplanes 18)

Type W.26

   The W.26 was a long-range reconnaissance seaplane in the CMGHFT category designed for an endurance of eight hours. This machine showed Friedrichshafen influences. This biplane was one of the first assignments that Hanns Klemm had with Brandenburg.(34) A large two-bay biplane, it could carry transmitting and receiving wireless apparatus. The state of the naval air war meant that it was soon converted to a C2MGHFT machine. The pilot was equipped with a synchronised Maxim 08/15 machine gun while the observer had a ring-mounted Parabellum. The upper wing was constructed in three pieces. The outer panels were swept back. The now standard Brandenburg float strut arrangement was used, leaving the inner bay devoid of cable bracing. It could also carry small bombs. The W.26 was delayed as Klemm was placed in charge of developing the revolutionary W.29 monoplane, the former project being shelved in the interim.
   The usual three prototypes were ordered, receiving MNs 1739-1741. No further development took place. One source states that they were used for medium-range reconnaissance in the North Sea. The three prototypes were discovered at the Warnemunde Testing Station by the Allies on 14 December 1918.

   (34) Hanns Klemm had gone to school with Heinkel. A civil engineer, he served in the Army on the outbreak of war. Wounded, he was discharged and went to work for Dornier in April 1917 as a specialist in metal construction and load calculation. He worked on the Dornier metal aircraft before being lured away by Heinkel


Brandenburg W.26 Specifications
Source Typenschau Gray & Thetford Branden. 3-View
Dimensions in m
Span, Upper m 18.80 18.8 18.800
Span, Lower m 18.80 - 18.800
Chord, m 2.450*
Length, m 12.79 13.015 -
Wing Area, m2 86.30 86.3 -
Empty Wt., kg 1,675 1,675 1,675
Loaded Wt., kg 2,490 2,490 2,490
Performance
Speed in km/hr 135 135 Ca. 135
Endurance - 8 hours -
Motor 260/275-hp Mercedes 260-hp Mercedes D.IVa 275-hp Mercedes
* Both upper and lower wings