Airco DH4 and DH4A

The Airco (Aircraft Manufacturing Company) Two seat bi-plane day-bomber

The DH4 (No 3696) first flew at Hendon in August 1916 and entered RFC service in March 1917. 1,449 DH4 were built in the UK, some 915 by AIRCO, with a further substantial number (circa.4,000)  in the USA by Boeing, Dayton-Wright, Fisher Body and Standard Aircraft. British sub-contract orders were placed with F.W. Berwick; Glendower Aircraft; Palladium Autocars; Vulcan Motor & Engineering; and Westland Aircraft Works.

The DH4 had open cockpits for its pilot and observer, the crew being separated by the fuel tank installed between them in the fuselage. There was one forward-firing machine gun and the observer was provided with one (or two) defensive 0.303 machine gun(s) mounted on a Scarff-ring to allow all round defence.

Power was initially provided by the 230hp BHP engine but several other engine types were fitted, of which the 375 hp Rolls-Royce Eagle VIII is regarded as being the most successful American-built aircraft were powered by the 400 hp Liberty L-12 engine, which was later adopted for the DH9A model. A later US-built derivative, the DH4M featured a fabric-covered steel tube fuselage.
The type proved very popular in service not least for its performance, manoeuvrability and pleasant flying characteristics.

Post-war, a single seat racing variant with cropped lower wings, the DH4R, won the 1919 Aerial Derby air race. The DH4A commercial variant had a small glazed cabin in the rear fuselage in which two passengers could be seated. Operators included AT&T Ltd, SNETA (Belgium), Handley Page Ltd and Instone Air Lines.

Specification (Eagle VIII)

Powerplant One 375 hp Rolls-Royce Eagle VIII
Span 43 ft 4.6 in
Maximum Weight   3,472 lb
Payload Pilot and observer and typical bomb load 450 lb (four 112 lb or two 230 lb bombs)
Maximum Speed 143 mph
Endurance 3.75 hr (470 Miles)