Hansa-Brandenburg KDW

KDW
Role	Floatplane fighter
National origin	German Empire
Manufacturer	Hansa und Brandenburgische Flugzeug-Werke
Designer	Ernst Heinkel
First flight	September 1916
Introduction	1916
Primary user	Imperial German Navy
Produced	1916-1918
Number built	58
Developed from	Hansa-Brandenburg D.I

The Hansa-Brandenburg KDW was a German single-engine, single-seat, fighter floatplane of World War I. The KDW – Kampf Doppeldecker, Wasser (Fighter Biplane, Water) – was adapted from the Hansa-Brandenburg D.I landplane to provide coastal defence over the North Sea.

It was produced under licence by the Austro-Hungarian manufacturer Phönix from 1916 in five batches, with progressively more powerful engines and armament, 58 aircraft in total being produced.

In 1916 the Imperial German Navy ordered the production of single-seat armed scout seaplanes (Jagdeinsitzer Wasser) to defend its North Sea seaplane stations against air attack. To deliver suitable aircraft quickly, the first designs were floatplanes based on existing landplane models. One such was the Hansa-Brandenburg KDW, adapted by the company's chief designer, Ernst Heinkel, from his Hansa-Brandenburg D.I.

The D.I was a single-seat scout with novel and distinctive "star strutter" wing bracing. On each side of the aircraft four vee struts, two facing up, two facing down, were joined by their vertices at a point midway between the upper and lower wings, forming an eight-armed star configuration that gave the plane its nickname Spinne (spider).

The KDW was essentially the D.I with a small increase in wingspan and mounted on a twin-float chassis. To counteract the keel effect resulting from the floats, which were below the aircraft's centre of gravity, vertical tailfin area was added below and later above the fuselage. Even with the added tailfin area, the aircraft's lateral stability – its tendency to return from a bank to vertical flight – was below par. Moreover, the deep fuselage tended to blanket the small tailfin and rudder, making directional stability and control very poor.

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