Airco D.H.4

Designed by Geoffrey dc Havilland, the Airco D.H.4 is regarded as the best single-engine day bomber of World War I. It outpaced all but the fastest German fighters and defended itself effectively; the pilot operated a fixed forward-firing Vickers gun and there was a moveable Lewis gun on the observer’s gun ring. The one major design
drawback was the distance between the pilot’s and observer’s cockpits, making inflight communication somewhat difficult.
The D.H.4 could carry two 230lb or four 112lb bombs. Fitted with a variety of in-line engines, it served with both the Royal Flying Corps and the Royal Naval Air Service, operating in Italy. Macedonia, Mesopotamia, Palestine, and Russia, as well as on the
Western Front.
A total of 1,449 D.H.4s were built in Britain and, after the United States entered the war in April 1917, the type was adopted for mass
production in that country.
Some 5.000 American D.H.4s were built, powered by Liberty engines. Nearly 2,000 of these reached the American Expeditionary Force in France before the war ended.
In the 1920s thousands of G.H.4s were flown in the United States in a variety of civilian roles. The aircraft was the mainstay of the US airmail service in its infancy.