The Airco D.H.6 was Geoffrey de Havilland's first training aircraft, and was a deliberately simple aircraft designed to be produced in large numbers in preparation for the massive expansion of the R.F.C. planned for 1917. Although a very large number of D.H.6s were produced it had a short lifespan as the R.F.C.'s main trainer before being replaced by the Avro 504K at the end of 1917.
The D.H.6 was designed to be easy and quick to build and to maintain. All of its major parts had straight sides, reducing the skill needed to produce them (the prototype had a typical curved de Havilland rudder but this was replaced by a straight edged version on production aircraft). The upper and lower mainplanes were interchangeable to make the aircraft easier to maintain. The 90hp R.A.F. 1A eight cylinder V air-cooled engine was bolted directly onto the top longerons of the fuselage, with no cowling, making it both easier to fit and maintain. The aircraft was designed to have a very low stall speed – it could safely be flow at 30mph, but to be unstable enough to make it a good training aircraft.
At least 2,282 D.H.6s were completed and another 600 were cancelled at the end of the war. So many were produced that the supply of R.A.F. engines ran short, and so some aircraft received 80hp Renault or 90hp Curtiss OX-4 engines instead.
The D.H.6 was used by training squadrons in the United Kingdom, in the Far East and at Point Cook, Australia, where the shape of its shared open cockpit earned it the nickname of 'The Dung Hunter'. The D.H.6 was also used as a communication aircraft by Home Defence Squadrons based in Britain.
At the end of 1917 the D.H.6 was replaced by the Avro 504K, leaving a large number of aircraft surplus to requirements. Three hundred of them went to the R.N.A.S, who used them for anti-submarine patrols around the coast of England and to the U.S.N. who used them for the same purpose from bases in the north east of Ireland. The D.H.6 was not a very successful naval patrol aircraft – it could only carry 100lb of bombs and its built-in instability meant that it was very tiring to fly for long periods of time. The type was only involved in one major attack, against the German submarine U.C.49 on 30 May 1918, but the submarine escaped intact.
The RAF still had 1,050 D.H.6s on charge at the end of 1918, but most of them had been declared obsolete and sold off by the end of 1919. Many survived in private hands to the end of the 1920s.
The last D.H.6s to be produced were a batch of sixty produced under license by Hispano at Guadalahara, starting in 1921, for use by the Spanish air force.
Engine: R.A.F. 1A
Wing span: 35ft 11in
Length: 27ft 3.5in
Height: 10ft 9.5in
Tare Weight: 1,460lb
All-up Weight: 2,027lb
Max Speed: 70mph
Duration: 2h 45min