The last of the Heinkel-designed single-seat fighter float seaplanes built by the Hansa- und Brandenburgische Flugzeug-Werke, the W.25, produced as a single prototype late in 1917, was the final development of the KDW. Reverting to the 150hp Benz Bz III engine used by the prototype and pre-production KDWs, the W.25 possessed an essentially similar fuselage, but discarded the "star" interplane strut arrangement in favour of normal strut bracing. Initially the prototype flew with ailerons on the upper wing only, but these were subsequently added to the lower wing, each pair being joined at the wingtip.by link struts. Armament comprised two synchronised 7.92mm LMG 08/15 machine guns. Having by this time lost interest in single-seat fighter floatplanes, the German Navy did not foster further development of the W.25.
Max take-off weight: 1182 kg / 2606 lb
Empty weight: 918 kg / 2024 lb
Wingspan: 10.40 m / 34 ft 1 in
Length: 8.80 m / 29 ft 10 in
Height: 3.45 m / 11 ft 4 in
Wing area: 36.53 sq.m / 393.21 sq ft
Max. speed: 160 km/h / 99 mph