На основе KD был разработан поплавковый одноместный разведчик-истребитель KDW. В серии строился увеличенный вариант под индексами W11 (с двигателем Bz.IV) и W25 (с Bz.III).
O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
During 1916 Ernst Heinkel prepared a design for a single-seat scout for the Austrian Army. Although conventional in most respects, the aircraft featured a novel system of wing bracing in the form of four vee struts joined in the centre of the wing bay by their apices. This arrangement gave a star configuration, and the aircraft was, in fact, dubbed "star strutter". The Brandenburg K.D. (Kampf Doppeldecker), as the type was designated, was license-built by the Austrian factories of Phonix and Ufag as the D I (Hansa Brandenburg D I (Ph) Series 28 and Hansa Brandenburg D I (Ufag) Series 65). Phonix subsequently developed the design on more conventional lines and introduced a more orthodox strut arrangement and empennage. This variant went into further production as their own D II and D III series.
In view of the demand for seaplane-station fighter defence aircraft and his considerable seaplane design experience, Heinkel decided to convert the K.D. to a seaplane fighter type as a stop gap, to reinforce the supply of Albatros W 4 and Rumpler 6BI seaplanes. In actual fact, the prototype adaptation amounted to little more than a slight increase in wingspan and mounting the K.D. airframe on a twin-float chassis. Later, the inclusion of a certain amount of fin area below the rear fuselage was found necessary to compensate the additional keel surface presented by the floats, and ultimately an upper fin was also added. Despite these modifications the K.D.W., like the landplane version, proved very difficult to fly. Due to the blanketing of the small rudder by the deep fuselage, directional stability was extremely poor, and recovery from a spin was more by luck than by any degree of skill.
The prototype (Marine No. 748) and early production models were fitted with the 150 h.p. Benz engine and a car-type radiator; likewise an interim production batch (Nos. 1067-1076), which also had additional outsplayed vee struts to brace the wingtips. All remaining aircraft were fitted with the 160 h.p. Maybach engine and flush-type radiator mounted in the centresection of the top wing to starboard of the centre. Exhaust manifolds were of the chimney type in the Benz-powered aircraft, except on the prototype, which had stub pipes. The Maybach K.D.W.s had a collector manifold with only a single ejector pipe showing on the starboard side.
Engines were neatly faired with hooded metal panels, which curved in from the upper longerons, giving a "head and shoulders" cross-section which afforded the pilot quite good forward vision. The fuselage itself was based on four spruce longerons, with ply formers forward and spruce spacers and transverse diagonal bracing members aft of the cockpit section. There was very little taper in fuselage depth. The curved decking maintained almost the same height as the depth between the longerons and extended right aft to the sternpost. The whole of the fuselage was plywood covered, as were also the vertical fins.
Tail surfaces were framed from steel tube and fabric covered. The rectangular rudder had a small balance portion atop the fuselage, but when the upper fin was introduced on the later models this was deleted. The large triangular tailplane, to which the unbalanced parallel chord elevators were hinged, was mounted directly on the upper longerons and braced to the underside of the fuselage with two streamlined steel struts.
The wings were of straightforward rectangular profile, of equal span and fabric covered. Their conventional wooden construction was based on two main spars, with a further auxiliary spar at approximately two-thirds chord, to which were hinged the unbalanced parallel-chord ailerons. The attachment point for the upper outboard vee of the "star-strut" interplane bracing was located almost at the extreme end of the aileron, and it was found in practice that the considerable overhang portion of the upper wing tended to flex as the ailerons were actuated, reducing the sensitivity of these controls. In consequence, a light steel-tube vee was fitted, splaying outward from the lower strut anchorage, to brace the upper wing more rigidly and make the aileron control more positive. The "star-struts" themselves were basically light-gauge circular steel tubes faired with plywood. Centre-section struts were of plain circular steel tube, like the auxiliary tip struts, and of inverted vee form.
The undercarriage chassis comprised a neat pair of N struts of steel tube faired with ply. The floats themselves, of single-step design, wedge-shaped forward and tapering to a vertical knife-edge at the stern, were wooden and built up on a framework of ply formers and spruce stringers and covered with mahogany ply. They were connected at the strut stations with rigid steel-tube spreaders and the complete chassis braced fore and aft with stranded cables.
An interesting point about the Heinkel K.D. and K.D.W. fighter prototypes is that they were developed structurally and aerodynamically before any thought seems to have been given to the armament. This was especially noticeable on the land aircraft, with guns mounted on the top wing. On the K.D.W.s a single synchronised Spandau machine-gun was mounted on the starboard side of the extreme nose, far beyond the reach of the pilot to correct any stoppage. Only on the final batch of twenty aircraft, delivered between October 1917 and February 1918, were twin Spandau guns fitted, clamped either side of the cockpit. By then the type was obsolescent and was being replaced by the far more efficient and flexible Brandenburg W 12. Altogether a total of 58 K.D.W.s were supplied.
Although these production batches of seaplanes may seem small, they must be viewed in comparison with total aircraft supplies, when by the end of the war a total of some 2,500 seaplanes had been produced, as compared with 44,000 aircraft for land warfare.
Description: Single-seat seaplane fighting scout.
Manufacturer: Hansa und Brandenburgische Flugzeug-Werke G.m.b.H.
One 150 h.p. Benz Bz III 6 cylinder in-line water-cooled engine.
One 160 h.p. Maybach Mb III 6 cylinder in-line water-cooled engine.
Dimensions: Span, 9.25 m. (30 ft. 4 1/4 in.). Length, 8 0 m. (26 ft. 3 in.). Height, 3.35 m. (10 ft. 11 7/8 in.). Area, 20 sq.m. (216 sq.ft.).
Weights: Empty, 940 kg. (2,068 lb.). Loaded, 1,210 kg (2,662 lb.).
Performance: Maximum speed, 170 km.hr. (106.25 m.p.h.). Climb, 1,000 m (3,280 ft.) in 5.9 min. 2,000 m. (6,560 ft.) in 14 min.; 3,000 m. (9,840 ft) in 21 mm. Duration 2 1/2 hr. with 160 litres fuel.
Armament: One fixed Spandau machine-gun forward mounted on starboard of nose. Last twenty aircraft were fitted with twin machine-guns.
Serial Numbers: Fifty-eight aircraft delivered. Marine Numbers: 748, 783, 784, 912-921, 1067-1076, 1380-1394, 1554-1573.
Brandenburg W 11
Built during late 1916, the W 11 was a slightly larger and more powerful version of the series-built K.D.W. single-seat fighter seaplane. Only two machines were built - Nos. 988-989. Engine, 200 h.p. Benz Bz IV. Span, 100 m. (32 ft. 9 3/4 in.). Length, 8.2 m. (26 ft. 10 7/8 in.). Height, 3.32 m. (10 ft. 10 5/8 in.). Area, 31.4 sq.m. (339 sq.ft.). Weights: Empty, 935 kg. (2,057 lb.). Loaded, 1,215 kg. (2,673 lb.). Speed, 176 km.hr. (110 m.p.h.). Armament, two Spandau machine-guns.
W.Green, G.Swanborough The Complete Book of Fighters
BRANDENBURG KDW Germany
The KDW twin-float single-seat fighter seaplane was essentially a conversion of the land-based KD (D I) to provide an interim aircraft for floatplane station defence. The only major change introduced on the prototype apart from provision of a twin-float chassis was some slight extension of the wings, but the fin area was later increased to compensate for the increased keel area resulting from the addition of the floats. The prototypes were fitted with the 150 hp Benz Bz III six-cylinder water-cooled engine, but apart from a pre-production batch of 10 similarly-powered aircraft, all subsequent examples of the KDW had the 160 hp Maybach Mb III six-cylinder water-cooled engine. The first production series was armed with a single synchronised 7,92-mm LMG 08/15 machine gun mounted on the starboard side of the nose, but the final batch of 20 delivered between October 1917 and February 1918 had a gun mounted on each side of the cockpit and additional Vee-type interplane bracing struts. A total of 58 KDW float fighters was delivered.
Max speed, 106 mph (170 km/h).
Time to 3,280 ft (1000 m), 5.9 min, to 6,560 ft (2 000 m), 14 min.
Range, 310 mis (500 km).
Empty weight, 1,673 lb (759 kg).
Loaded weight, 2,290 lb (1 039 kg).
Span, 30 ft 6 1/8 in (9,30 m).
Length, 25 ft 9 1/2 in (7,86m).
Height, 10 ft 11 7/8 in (3,35m).
Wing area, 313.77 sq ft (29,15 m2).
BRANDENBURG W 11 Germany
A heavier and more powerful derivative of the KDW, the W 11 single-seat twin-float fighter biplane was powered by a 220 hp Benz Bz IVa water-cooled engine and retained the "star” interplane bracing arrangement of its predecessor. Armament consisted of two synchronised LMG 08/15 machine guns, and two prototypes were completed during February-March 1917. No series production was undertaken.
Max speed, 109 mph (176 km/h).
Time to 3,280 ft (1 000 m), 4.0 min.
Range, 217 mis (350 km).
Empty weight, 2,061 lb (935 kg).
Loaded weight, 2,718 lb (1233 kg).
Span, 33 ft 1 2/3 in (10,10 m).
Length, 26 ft 6 7/8 in (8,10 m).
Height, 10 ft 10 3/4 in (3,32 m).
Wing area, 338.2 sq ft (31,42 m2).