The DH-4 was an ever-present element of the US Army Air Service both during and following World War I. When the US entered World War I in April 1917, the Aviation Section of the Signal Corps only had 132 aircraft, all obsolete. Modeled from a combat tested British De Havilland design, the DH-4 was the only US built aircraft to see combat during World War I. During World War I, the Air Service used the DH-4 primarily for day bombing, observation, and artillery spotting. The first American-built DH-4 arrived in France in May 1918, and the 135th Aero Squadron flew the first DH-4 combat mission in early August. 1,213 DH-4s were delivered to France by war’s end.
With few funds to buy new aircraft in the years following World War I, the US Army Air Service used the DH-4 in a variety of roles, such as transport, air ambulance, photographic plane, trainer, target tug, forest fire patroller and even as an air racer. In addition, the US Post Office operated the DH-4 as a mail carrier.
The DH-4 also served as a flying test bed at McCook Field in the 1920s, testing turbosuperchargers, propellers, landing lights, engines, radiators, and armament. There were a number of notable DH-4 flights such as the astounding New York to Nome, Alaska flight in 1920, the record breaking transcontinental flight in 1922 by Jimmy Doolittle and the first successful air-to-air refueling in 1923.
1,538 DH-4s were modified in 1919-1923 to DH-4Bs by moving the pilot’s seat back and the now unpressized gas tank forward, correcting the most serious problems in the DH-4 design. A further improved version was the DH-4M whereby over 300 DH-4s received new steel tube fuselages.
By the time it was finally retired from service in 1932, the DH-4 had developed into over 60 variants.