Hurel-Dubois HD.31

HD.31, HD.32, and HD.34
The prototype HD.31 demonstrating at Coventry Airport in June 1954
Role	Airliner
National origin	France
Manufacturer	Hurel-Dubois
First flight	29 December Template:Avyear
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.

Design and construction

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.

Production and Operation

HD.34 survey aircraft of the IGN at its base at Creil airfield in 1967

A batch of eight aircraft was, however, ordered by the Institut Géographique National (IGN), based at Creil airfield to the north of Paris. The aircraft's wing design 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.

Variants

The Prototype HD31 demonstrating at Coventry Airport in June 1954

• HD.31 - prototype with Wright Cyclone C7BA1 radial engines (1 built)
• HD.32 - prototype with Pratt & Whitney R-1830 radial engines (2 built)
  • HD.321 - prototype with Wright Cyclone 982 engines and single tail (2 converted from HD.32 by replacing twin boom with a single boom)
  • 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)

Operators

France

• Institut Geographique National

Specifications (HD.34)

General characteristics

• Crew: Five

Performance

References

• Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions. pp. 523–24. ISBN 0-7106-0710-5.
• World Aircraft Information Files. London: Bright Star Publishing. pp. File 896 Sheet 30. ISBN 1-156-94382-5.
• Simpson, R. W. (1995). Airlife's General Aviation. Shrewsbury: Airlife Publishing. p. 424. ISBN 1-85310-577-5.
• "Hurel-Dubois Transports". Flight: 676. 1952. Retrieved 2008-05-04. {{cite journal}}: Unknown parameter |month= ignored (help)
• "Flying in the Hurel-Dubois". Flight: 180. 1953. Retrieved 2008-05-04. {{cite journal}}: Unknown parameter |month= ignored (help)
• "Hurel-Dubois H.D.32". Flight: 793. 1954. Retrieved 2008-05-04. {{cite journal}}: Unknown parameter |month= ignored (help)
• "H.D.321". Flight: 62. 1956. Retrieved 2008-05-04. {{cite journal}}: Unknown parameter |month= ignored (help)
• "Flying the H.D.34". Flight: 479. 1957. Retrieved 2008-05-04. {{cite journal}}: Unknown parameter |month= ignored (help)