Hurel-Dubois HD.31

__NOTOC__ Infobox Aircraft
name=HD.31, HD.32, and HD.34


caption=
type=Airliner
national origin=France
manufacturer=Hurel-Dubois
designer=
first flight=29 December avyear|1953
introduced=
retired=
status=
primary user="Institut Géographique National"
more users=
produced=
number built=10
variants with their own articles=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".

Variants

* HD.31 - prototype with Wright Cyclone C7BA1 radial engines (1 built)
* HD.32 - prototype with Pratt & Whitney R-1830 radial 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)

pecifications (HD.34)

aerospecs
ref=
met or eng?=met

crew=Five
capacity=
length m=23.57
length ft=77
length in=4
span m=45.30
span ft=148
span in=7
height m=
height ft=
height in=
wing area sqm=100.0
wing area sqft=1,076
empty weight kg=12,300
empty weight lb=27,060
gross weight kg=18,600
gross weight lb=40,920

eng1 number=2
eng1 type=Wright Cyclone 982-C9-HE2
eng1 kw=1,140
eng1 hp=1,525
eng2 number=
eng2 type=
eng2 kw=
eng2 hp=

max speed kmh=280
max speed mph=175
cruise speed kmh=
cruise speed mph=
range km=2,200
range miles=1,375
endurance h=
endurance min=
ceiling m=8,000
ceiling ft=26,200
climb rate ms=
climb rate ftmin=

armament1=
armament2=
armament3=
armament4=
armament5=
armament6= aircontent
see also=
related=
similar aircraft=
lists=

References

*
*
*
*
*
*
*
*