O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
Halberstadt CLS I
Designed to succeed the CL II and CL IV types, the CLS I was even smaller and lighter, and it was also faster. Type tested on 2nd October 1918, it came too late to go into production. But for the absence of curvature in the lower wing roots and the built-up rear cockpit, the CLS I might be confused with the CL IV: construction was almost identical. Further development in the shape of CLS II and CLS X, with 3.5 cm. revolver cannon, remained no more than projects. Engine, 160 h.p. Mercedes D III. Span, 9.7 m. (31 ft. 9 7/8 in.). Length, 6.95 m. (22 ft. 9 5/8 in.). Height, 3.05 m. (10 ft. 0 1/8 in.). Area, 26.4 sq.m. (285 sq.ft.). Weights: Empty, 682 kg. (1,500 lb.). Loaded, 1,102 kg. (2,424 lb.). Speed, 185 km.hr. (115.625 m.p.h.). Climb, 4,500 m. (14,760 ft.) in 36 min. Armament, one Parabellum and two Spandau machine-guns.
W.Green, G.Swanborough The Complete Book of Fighters
HALBERSTADT CLS I Germany
A requirement was formulated in September 1918 for a two-seat fighter optimised for the close air support role. Climb rate was considered of secondary importance, emphasis being placed on speed, manoeuvrability and dive capability. The Halberstadter Flugzeugwerke responded with a design based on the C VIII reconnaissance biplane, but having reduced wing span and a 160 hp Mercedes D IIIa engine, and designated Cls I. The requirement resulting in the Cls I had specified an increase in useful load (by comparison with the CL IV) from 750 lb (340 kg) to 926 lb (420 kg), apparently to cater for a twin fixed-gun armament and a larger load of anti-personnel bombs, but the provision of a 20-mm Becker cannon for the gunner was also proposed. The Cls I was type tested in October 1918, but when the static testing of components terminated on 6 December, some strengthening of the tail surfaces was called for. Only three or four prototype Cls I close air support fighters were completed.
Max speed, 115 mph (185 km/h).
Empty weight, 1,504 lb (682 kg).
Loaded weight, 2,430 lb (1102 kg).
Span, 31ft 9 7/8 in (9,70 m).
Length, 22 ft 9 5/8 in (6,95 m).
Height, 10 ft 0 in (3,05 m).
Wing area, 284.18 sq ft (26,40 m2).