A single prototype of the De Havilland DH54 Highclere biplane airliner was built to Air Ministry Specification 40/22 which called for a larger version of the DH34, to increase passenger capacity from 9 to 12.
The aircraft (G-EBKI) was first flown first by Captain Hubert Broad on 18th June 1925.
The DH54 incorporated a number of advanced features, including high-lift flaps and an undercarriage that could be jettisoned to increase safety, should the aircraft have to be ditched. It was configured as a conventional single engine two-bay biplane with fabric covered wings and an all-wooden frame fuselage covered with plywood.
The two crew sat in an open cockpit ahead of the upper wing leading edge. Passengers were seated in four rows with single seats on the left and double seats to the right. A passenger lavatory was installed in the rear fuselage and cabin heating was also provided. Power was provided by a single 650 hp Rolls-Royce Condor IIIA water-cooled engine driving a 4-blade propeller.
By the afternoon of its maiden flight, G-EBKI was already carrying non-fare paying passengers. The DH54 was on show in the New Types Park displayed at the RAF Display at Hendon on 25th and 26th June 1925.
The type was then demonstrated at the Lympne Bank Holiday race meeting on 1st August 1925, taking part in a race with a full passenger load and just winning at a speed of at 103.4 mph. Owned throughout its life by the Air Ministry, the DH54 successfully passed its airworthiness tests at Martlesham Heath in early 1926.
By that time, however, Imperial Airways had introduced a policy that passengers would only be carried in multi-engine aircraft and it was this that sounded the death knell for further development and production of the type.
G-EBKI was briefly used at RAE Farnborough from March 1926 and was later considered for use as a freighter by Imperial Airways, to whom it was loaned in November 1926. Unfortunately, it was never adopted for this role and shortly afterwards the aircraft was damaged beyond repair by the collapse of a hangar at Croydon following a heavy snowfall on 1st February 1927.
2 variants with alternative engines were considered for design (DH55 & DH57) although neither of these came to fruition.
|Powerplant||One 650 hp Rolls-Royce Condor IIIA engine|
|Span||68 ft 2 in|
|Maximum Weight||11,250 lb|
|Capacity||2 pilots in an open cockpit and 12 passengers in an enclosed cabin|
|Maximum Speed||110 mph|
|Cruising Speed||100 mph|
One only, G-EBKI.
Nil, G-EBKI was destroyed in a hangar collapse in February 1927.