W.Green, G.Swanborough The Complete Book of Fighters

HAFELI DH-4 (M IV) Switzerland

   Designed by August Hafeli and owing much to experience gained with the DH-3 (M III) series of two-seat reconnaissance aircraft, the DH-4 (M IV) single-seat fighter was powered by a 150 hp Hispano-Suiza HS-41 eight-cylinder water-cooled engine. The prototype, built by the K + W (Konstruktions-Werkstatte) at Thun, was flown early in 1918. Of wooden construction with fabric covering and carrying an armament of one synchronised machine gun, the DH-4 was found to possess a disappointing performance and poor handling characteristics. Tests by the Swiss Fliegertruppe were initiated in May 1918, but terminated in August, when the sole prototype was returned to the K + W for structural load testing, no further flight trials being undertaken.

Max speed, 92 mph (148 km/h).
Initial climb, 886 ft/min (4,5 m/sec).
Range, 186 mis (300 km).
Empty weight, 1,410 lb (640 kg).
Loaded weight, 1,951 lb (885 kg).
Span, 32 ft 1 4/5 in (9,80 m).
Length, 19 ft 8 1/4 in (6, 00 m).
Height, 8 ft 6 1/3 in (2,60 m).
Wing area, 236.8 sq ft (22, 00 m2).