Hurel-Dubois HD.31

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HD.31, HD.32, and HD.34
Type	Airliner
National origin	France
Manufacturer	Hurel-Dubois
Maiden flight	29 December 1953
Primary user	Institut Géographique National
Number built	10

The Hurel-Dubois HD.31, HD.32, and HD.34 were a family of civil aircraft produced in France in the 1950s, based on Maurice Hurel's high aspect ratio wing designs. Tests with the Hurel-Dubois HD.10 research aircraft had validated Hurel's ideas about the practicality of such wings, and the French government agreed to sponsor the construction of two prototypes of a medium-range airliner utilising this same principle. These aircraft, the HD.31 and HD.32 were conventional designs in all respects other than their unorthodox wings, and differed from one another only in their powerplants, although both were later converted to use the same engines. The twin-tails originally fitted were also later replaced by a large single tail fin, and with their new engines and tails, they were redesignated HD.321.01 and HD.321.02. Air France originally placed an order for 24 aircraft to use as feederliners, but these were cancelled before they were constructed.

A batch of eight aircraft was, however, ordered by the Institut Géographique National. The aircraft's wings made it ideal for long-duration, low-speed flight, ideal for aerial photography and survey work. These machines were designated HD.34 and were fitted with an extensively-glased nose and a retractable nosewheel. They flew with IGN between the late 1950s and mid 1970s. A single example remains airworthy, operated by the Association des Mécaniciens-Pilotes d'Aéronefs Anciens.

[edit] Variants

• HD.31 - prototype with Wright Cyclone C7BA1 engines (1 built)
• HD.32 - prototype with Pratt & Whitney R-1830 engines (1 built)
  • HD.321 - prototype with Wright Cyclone 982 engines and single tail (2 converted from HD.31 and HD.32)
  • HD.324 - turboprop version with Rolls-Royce Dart engines (not built)
• HD.33
  • HD.331 - projected militarised version for use as troop transport or air ambulance (not built)
• HD.34 - aerial survey version for IGN (8 built)

[edit] Specifications (HD.34)

General characteristics

• Crew: Five
• Length: 23.57 m (77 ft 4 in)
• Wingspan: 45.30 m (148 ft 7 in)
• Wing area: 100.0 m² (1,076 ft²)
• Empty weight: 12,300 kg (27,060 lb)
• Gross weight: 18,600 kg (40,920 lb)
• Powerplant: 2 × Wright Cyclone 982-C9-HE2, 1,140 kW (1,525 hp) each

Performance

• Maximum speed: 280 km/h (175 mph)
• Range: 2,200 km (1,375 miles)
• Service ceiling: 8,000 m (26,200 ft)

[edit] References

• Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions, 523-24. 
• World Aircraft Information Files. London: Bright Star Publishing, File 896 Sheet 30. 
• Simpson, R. W. (1995). Airlife's General Aviation. Shrewsbury: Airlife Publishing, 424. 
• "Hurel-Dubois Transports" (28 November 1952). Flight: 676. 
• "Flying in the Hurel-Dubois" (7 August 1953). Flight: 180. 
• "Hurel-Dubois H.D.32" (18 June 1954). Flight: 793. 
• "H.D.321" (6 July 1956). Flight: 62. 
• "Flying the H.D.34" (20 September 1957). Flight: 479. 

v • d • e Aircraft produced by Hurel-Dubois HD.10 • HD.31 • HD.40 Joint project: HDM.105

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