The de Havilland DH.54 Highclere was a single-engined 15-passenger biplane airliner designed to replace the DH.34. Its development ended when Imperial Airways decided to use only multi-engined types.
The DH.54 Highclere[1] was designed to Air Ministry specification 40/22 for a larger version of the very successful DH.34 and the two aircraft had much in common, both in construction and general layout. Compared with the DH.34, the Highclere's passenger complement increased from nine to twelve, its all-up weight by 56% and its wing area by 70%. They were both single-engined two-bay biplanes with fabric-covered wooden wings and with wooden-framed fuselages covered with thin plywood.[1]
Size apart, the wings of the Highclere differed[1] in having no stagger, no upper wing dihedral and in having a larger inter-wing gap, the upper wing now attached to the fuselage by cabane struts rather than directly to the upper fuselage. In response to criticism of the DH.34's high landing speed, full-span flaps were fitted. To reduce the hazards of ditching, the undercarriage could be jettisoned and the fuselage was made watertight. Passengers sat in four rows of seats, singles on the left and doubles on the right. A rearrangement of luggage space allowed room for toilets. The Highclere had balanced elevators. The weight increase required an increase in power, so the Highclere used a 650 hp (485 kW) Rolls-Royce Condor IIIA water-cooled inline engine which lengthened the nose and drove a four-bladed propeller of 14 ft (4.27 m) diameter.[1]
Operational historyedit
The Highclere was first flown by H.S. Broad on 18 June 1925[2] and was soon carrying non-paying passengers and winning races.[1] Owned by the Air Ministry throughout its life, it went to RAF Martlesham Heath for successful airworthiness tests early in 1926, with the Certificate of Airworthiness awarded on 23 April 1926. By then, though Imperial Airways had decided no longer to transport passengers in single-engined types for safety reasons and the sole Highclere was transferred to RAE Farnborough on 7 March 1926 for experimental work. On 7 November 1926[2] it was loaned to Imperial Airways at Croydon Airport as a freighter and some thought was given to modifications to make the Highclere better fitted to this role,[1] but it was destroyed when a hangar collapsed in heavy snow at Croydon on 1 February 1927.
Unbuilt variantsedit
DH.55
Unbuilt design for 12-seat transport powered by three 120 hp (90 kW) Airdisco engines.[3]
DH.57
Unbuilt derivative of DH.55 with three 230 hp (172 kW) Siddeley Puma engines.[3]
Jackson, A.J. (1978). de Havilland Aircraft since 1909. London: Putnam Publishing. ISBN0-370-30022-X.
Jackson, A.J. (1987). De Havilland Aircraft since 1909 (3rd ed.). London: Putnam. ISBN0-85177-802-X.
Jackson, A.J. (1988). British Civil Aircraft 1919-1972 vol II. London: Putnam Publishing. ISBN0-85177-813-5.
January 01, 1970
havilland, highclere, havilland, highclere, single, engined, passenger, biplane, airliner, designed, replace, development, ended, when, imperial, airways, decided, only, multi, engined, types, highclere, role, airliner, national, origin, united, kingdom, manuf. The de Havilland DH 54 Highclere was a single engined 15 passenger biplane airliner designed to replace the DH 34 Its development ended when Imperial Airways decided to use only multi engined types Highclere Role Airliner National origin United Kingdom Manufacturer de Havilland Aircraft Co Ltd First flight 18 June 1925 Retired 1927 Number built 1 Contents 1 Development 2 Operational history 3 Unbuilt variants 4 Specifications 5 ReferencesDevelopment editThe DH 54 Highclere 1 was designed to Air Ministry specification 40 22 for a larger version of the very successful DH 34 and the two aircraft had much in common both in construction and general layout Compared with the DH 34 the Highclere s passenger complement increased from nine to twelve its all up weight by 56 and its wing area by 70 They were both single engined two bay biplanes with fabric covered wooden wings and with wooden framed fuselages covered with thin plywood 1 Size apart the wings of the Highclere differed 1 in having no stagger no upper wing dihedral and in having a larger inter wing gap the upper wing now attached to the fuselage by cabane struts rather than directly to the upper fuselage In response to criticism of the DH 34 s high landing speed full span flaps were fitted To reduce the hazards of ditching the undercarriage could be jettisoned and the fuselage was made watertight Passengers sat in four rows of seats singles on the left and doubles on the right A rearrangement of luggage space allowed room for toilets The Highclere had balanced elevators The weight increase required an increase in power so the Highclere used a 650 hp 485 kW Rolls Royce Condor IIIA water cooled inline engine which lengthened the nose and drove a four bladed propeller of 14 ft 4 27 m diameter 1 Operational history editThe Highclere was first flown by H S Broad on 18 June 1925 2 and was soon carrying non paying passengers and winning races 1 Owned by the Air Ministry throughout its life it went to RAF Martlesham Heath for successful airworthiness tests early in 1926 with the Certificate of Airworthiness awarded on 23 April 1926 By then though Imperial Airways had decided no longer to transport passengers in single engined types for safety reasons and the sole Highclere was transferred to RAE Farnborough on 7 March 1926 for experimental work On 7 November 1926 2 it was loaned to Imperial Airways at Croydon Airport as a freighter and some thought was given to modifications to make the Highclere better fitted to this role 1 but it was destroyed when a hangar collapsed in heavy snow at Croydon on 1 February 1927 Unbuilt variants editDH 55 Unbuilt design for 12 seat transport powered by three 120 hp 90 kW Airdisco engines 3 DH 57 Unbuilt derivative of DH 55 with three 230 hp 172 kW Siddeley Puma engines 3 Specifications editData from Jackson 1978 pp 212General characteristicsCrew two Capacity twelve Length 51 ft 0 in 15 54 m Wingspan 68 ft 2 in 20 78 m Height 15 ft 2 5 in 4 64 m Wing area 1 004 sq ft 93 27 m2 Empty weight 6 768 lb 3 070 kg Gross weight 11 250 lb 5 103 kg Powerplant 1 Rolls Royce Condor IIIA 650 hp 485 kW Performance Maximum speed 110 mph 177 km h 96 kn Cruise speed 100 mph 161 km h 87 kn Range 400 mi 644 km 350 nmi Rate of climb 580 ft min 2 95 m s References edit nbsp Wikimedia Commons has media related to De Havilland DH 54 Highclere a b c d e f Jackson 1978 pp 210 2 a b Jackson 1988 p 302 a b Jackson 1987 p 519 Jackson A J 1978 de Havilland Aircraft since 1909 London Putnam Publishing ISBN 0 370 30022 X Jackson A J 1987 De Havilland Aircraft since 1909 3rd ed London Putnam ISBN 0 85177 802 X Jackson A J 1988 British Civil Aircraft 1919 1972 vol II London Putnam Publishing ISBN 0 85177 813 5 Retrieved from https en wikipedia org w index php title De Havilland Highclere amp oldid 1017273407, wikipedia, wiki, book, books, library,
