O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
Albatros D IX
The D IX, which appeared early in 1918, marked the introduction of a simplified fuselage structure with slab sides and a flat bottom. Nose entry was somewhat slipshod by previous Albatros standards, and the in-line formula was revised, with no spinner. The wings were similar to those of the D VII, but additionally stayed at the intersection of the flying and landing wires, with short link struts in much the same fashion as the French Spad S VII and S XIII. Only one example was built. Engine, 180 h.p. Mercedes D IIIa. Span, 10.4 m. (34 ft. 1 1/2 in.). Length, 6.65 m. (21 ft. 9 7/8 in.). Height, 2.75 m. (9 ft. 0 3/8 in.). Weights: Empty, 677 kg. (1,489 lb.). Loaded, 897 kg. (1,973 lb.). Speed, 155 km.hr. (96.875 m.p.h.). Climb, 1,000 m. (3,280 ft.) in 4 min., 5,000 m. (16,400 ft.) in 35 min. Duration, 1.5 hr. Armament, twin Spandau machine-guns.
Albatros D X
Another of the early 1918 prototypes from Albatros was the D X. The slab-sided fuselage of the D IX was retained, but a neatly spinnered vee-eight Benz IIIb of 195 h.p. was installed. Simplified wing bracing utilizing I struts was introduced, and the centre-section bracing was reinforced by a strut running right down to the lower wing root. This aircraft, serialled 2206/18, took part in the second D types Competition at Adlershof in June 1918. At a loaded weight of 888 kg. (1,954 lb.), it attained 5,000 m. (16,400 ft.) in 22 min., but on another occasion took 35.6 min. to reach the same height, taking 17 min to climb the last 1,000 m. Span, 9.84 m. (32 ft. 3 3/8 in.). Length, 618 m. (20 ft. 3 1/4 in.). Height, 2.75 m. (9 ft. 0 3/8 in.). Weights: Empty, 666 kg. (1,465 lb.). Loaded, 905 kg. (1,991 lb.). Speed, 170 km.hr. (106.25 m.p.h.). Duration, 1.5 hr. Armament, twin Spandau machine-guns.
W.Green, G.Swanborough The Complete Book of Fighters
ALBATROS D IX Germany
Unlike previous Albatros fighters, the DIX featured a slab-sided, flat-bottomed fuselage. The wings were similar to those of the D VII, as were also the tail surfaces, power was provided by a 180 hp Daimler D IIIa engine, and armament consisted of the usual twin synchronised 7,92-mm LMG 08/15 machine guns. The sole prototype appeared early in 1918, but performance proved disappointing and development was discontinued.
Max speed, 96 mph (155 km/h).
Time to 3,280 ft (1000 m), 4 min.
Endurance, 1.5 hrs.
Empty weight, 1,492 lb (677 kg).
Loaded weight, 1,977 lb (897 kg).
Span 34 ft 1 1/2 in (10,40 m).
Length, 21 ft 9 7/8 in (6,65 m).
ALBATROS D X
Developed in parallel with the DIX and possessing a similar slab-sided fuselage, the D X was powered by a 195 hp Benz Bz IIIbo eight-cylinder water-cooled engine, and participated in the second D-type Contest held at Adlershof in June 1918. Armament comprised the usual pair of machine guns. Development progressed no further than prototype trials.
Max speed, 106 mph (170 km/h).
Endurance, 1.5 hrs.
Empty weight, 1,468 lb (666 kg).
Loaded weight, 1,995 lb (905 kg).
Span, 32 ft 3 1/3 in (9,84 m).
Length, 20 ft 3 1/3 in (6,18m).
J.Herris Albatros Aircraft of WWI. Vol.4: Fighters (A Centennial Perspective on Great War Airplanes 27)
Well before the First Fighter Competition Albatros was aware that its workhorse D.Va was no longer competitive and designed the D.IX, using the same 170 hp Mercedes D.IIIa engine but with a wing cellule based on that of the Spad fighter. The D.IX was completed in late 1917, but it crashed on January 18, 1918 while being prepared for the competition. This eliminated any chance Albatros, then the largest fighter supplier, had to win the competition.
The crash investigation determined the most likely cause of the crash was wing failure, and Idflieg cancelled the D.IX. In any case, the D.IX had demonstrated mediocre performance.
Two Albatros D.X fighter prototypes, serials 2206/18 and 2207/18, were being built in February 1918. Using prototype 195 hp Benz Bz.IIIbm (geared) V8 engines, they had a single-bay wing design with streamlined I-struts. Initial flight testing in April gave encouraging results, especially flying qualities, but static load tests on May 31 resulted in failure of the fuselage lift cable. After reinforcement tests were successfully completed on June 14, the D.X was approved for front-line service providing the fuel tank fittings, undercarriage struts, and rear center-section struts were reinforced. During the Second Fighter Competition prototype 2206/18 demonstrated mediocre climb. During the debriefing sessions after flight comparisons the D.X was ignored by the fighter pilots evaluating the competitors, eliminating any possibility of production.
Albatros Fighter Specifications
D.VI D.VII/1 D.VII/2 D.IX D.X
Engine 160 hp Mercedes D.III 195 hp Benz Bz.IIIbo 195 hp Benz Bz.IIIbo 170 hp Mercedes D.IIIa 195 hp Benz Bz.IIIbm
Span (Upper) 9.80 m 9.30 m 9.32 m 10.40 m 9.90 m
Span (Lower) - 8.20 m 8.32 m 10.20 m 9.15 m
Chord (Upper) 1.6 m 1.3 m 1.3 m 1.3 m 1.3 m
Chord (Lower) - 1.3 m 1.3 m 1.3 m 1.3 m
Gap - 1.32 m 1.33 m 1.32 m 1.37 m
Stagger - 0.18 m 0.18 m 0.17m 0.30 m
Wing Area - 20.5 m2 20.9 m2 24.0 m2 22.9 m2
Length 7.75 m 6.62 m - 6.66 m 6.18 m
Height 2.79 m 2.68 m - 2.75 m 2.74 m
Empty Weight 638 kg 630 kg 750 kg 647 kg 667 kg
Useful Load 242 kg 255 kg 190 kg 220 kg 239 kg
Loaded Weight 880 kg 885 kg 940 kg 897 kg 906 kg
Wing Loading - 43.2 kg/m2 45.0 kg/m2 37.4 kg/m2 39.6 kg/m2
Power Loading 5.50 kg/hp 4.54 kg/hp 4.82 kg/hp 5.28 kg/hp 4.65 kg/hp
Max. Speed - - - 165 km/h 170 km/h
Climb, 1,000 m - - - 4 minutes -
Climb, 2,000 m - - - 8.8 minutes -
Climb, 3,000 m - - - 14.8 minutes -
Climb, 4,000 m - - - 22.8 minutes -
Climb, 5,000 m - - - 35 minutes -
Climb, 6,000 m - - - - -
Notes: All were armed with two machine guns. D.VI track 2.72 m.