The DH27 'Derby' was a large, single engine, two-bay biplane designed to Air Ministry Specification 2/20 with two prototypes (J6894 & J6895) being built and powered by the 650 hp Rolls-Royce Condor engine. The type was intended for service as a long-range heavy day bomber.
Although the design was initiated by Airco, it was completed by the newly-formed De Havilland Aircraft Co Ltd and became their first military aircraft design.
Apart from its large size, the type was distinguished by a fully-faired centre-section containing the 212 gallon fuel tank and eliminating the normal centre-section struts. Given its large wingspan of more than 64 ft, it is not surprising that a 'folding-wing' arrangement was provided to make hangarage more efficient.
The crew comprised pilot and gunner who were seated high-up in open cockpits whilst the navigator / bomb aimer sat in an enclosed cabin with three portholes on each side.
The first prototype (J6894) flew for the first time on 13th October 1922 at Stag Lane with the second aircraft following on 22nd March 1923.
Unfortunately for De Havilland, the Avro Aldershot (designed to the same specification) offered better performance than the all-wooden DH27. The Aldershot was not only lighter and had a better overall performance but it also carried its bombload internally and so it was the Avro design that was chosen for RAF service in January 1923.
Thereafter, the two De Havilland DH27 prototypes were moved to Martlesham Heath and the Isle of Grain Naval Station, although they were little used other than for the occassional testing.
|Powerplant||One 650 hp Rolls-Royce Condor III engine|
|Span||64 ft 6 in|
|Maximum Weight||11,545 lb|
|Capacity||Pilot, navigator and rear gunner positions; intended bomb load four 550 lb bombs carried internally. Single Lewis gun (mid-fuselage) for self-defence.|
|Maximum Speed||105 mph at sea level|
|Number built||Two only: J6894 and J6895|