Hurel-Dubois Miles HDM.105

HDM.105
Role	Very high aspect ratio wing research
National origin	France / United Kingdom
Manufacturer	H.D. et M. (Aviation), Ltd. (Hurel-Dubois - wings / F.G. Miles Ltd. - fuselage and engines)
Designer	Maurice Hurel
First flight	31 March 1957
Number built	1
Developed from	Miles Aerovan

The Hurel-Dubois Miles HDM.105 was a transport aircraft fitted with very high aspect ratio wings for research purposes, building on research carried out with the Hurel-Dubois HD.10, and a stepping point to the planned production HDM.106 Caravan. The HDM.105/HDM.106 provided the starting point for the design of the Short SC.7 Skyvan.^{[citation needed]}

Design and development

Maurice Hurel [fr], a French aircraft designer, became a champion of very high aspect ratio wings in a bid to significantly reduce induced drag, similar to the "Davis wing" of the Consolidated B-24 Liberator, but with much higher aspect ratios. After testing his wing design on the diminutive HD.10, Hurel was ready to progress to a full size transport aircraft, a joint venture between F.G. Miles Ltd. and Hurel-Dubois [fr], fitting a Miles Aerovan with a very high aspect ratio wing and carrying out comparison tests.^[1]

The HDM.105 utilised the fuselage, tail unit and engines from Miles Aerovan Mk.4 G-AOJF, fitted with a Hurel designed 75 ft 4 in (23 m) span 20.5:1 aspect ratio wing of NACA laminar flow sections, supported on aerofoil section lifting struts. The wings were fitted with double-slotted flaps actuated by Miles electric actuators from the original Aerovan. Roll control was by differential ailerons and inter-connected upper-surface spoilers. With no room for fuel in the slender wings, 13 imp gal (16 US gal; 59 L) fuel tanks were fitted in the vertical undercarriage strut fairings.^[2]

Operational history

The HDM.105, with B-class registration G-35-3 (subsequently re-registered G-AHDM), was first flown on 31 March 1957 by I.A. Forbes, but was later damaged beyond repair in a landing accident at Shoreham on 28 June 1958 and dismantled.^[2]

Variants

HDM.106 Caravan

Following the successful testing of the HDM.105 the joint company H.D. et M (Aviation) Ltd, was established to exploit derivatives. The HDM.106 Caravan was to have been an all-metal 8,000 lb (3,629 kg)transport aircraft, with 75 ft (23 m) span wings, powered by 2x 290 hp (216 kW) Lycoming GO-480, 2x 340 hp (254 kW) Lycoming GSO-480B or 2x 320 hp (239 kW) Turbomeca Astazou I engines, but the HDM.106 did not progress beyond the drawing board with H.D. et M (Aviation) Ltd.^[3]^[4]

The design for the HDM.106 was sold to Shorts who developed it into the very successful Short SC.7 Skyvan, but with a much reduced, moderately high, aspect ratio of 11:1.^[2]

HDM.107 Aerojeep

The H.D.M.107, known as the Aerojeep, was a military version of the HDM.106 to a STOL light transport requirement of the US Army, to be powered by two 800 shp (597 kW) Lycoming T53 turboprop engines.

HDM.108

An enlarged HDM.106 designed by Hurel-Dubois.^[2]

Miles M.111

The Miles M.111 was proposed as a light single-engined transport utilising the outer wings and struts of the HDM.105, powered by a single 320 shp (239 kW) Turbomeca Astazou turboprop engine.^[2]

Specifications (HDM.105)

Data from Flight : Foretaste of the Caravan - HDM.105 handling HDM.106 prospects,^[1] Jane's All the World's Aircraft 1958-59,^[4] Miles aircraft since 1925^[2]

General characteristics

Crew: 2
Capacity: up to 9 passengers or freight
Length: 10.46 m (34 ft 4 in)
Wingspan: 22.96 m (75 ft 4 in)
Height: 4.24 m (13 ft 11 in)
Wing area: 25.7 m² (277 sq ft) wings only, 36 m² (390 sq ft) including struts
Aspect ratio: 20.5:1
Airfoil: root: NACA 63₄-420; tip: NACA 63₁-412
Empty weight: 1,460 kg (3,219 lb)
Gross weight: 2,799 kg (6,170 lb)
Fuel capacity: 120 L (26 imp gal; 32 US gal) in left and right vertical undercarriage strut fairings
Powerplant: 2 × Blackburn Cirrus Major III 4-cylinder inverted air-cooled in-line piston engines, 116 kW (155 hp) each
Propellers: 2-bladed Fairey fixed-pitch propellers

Performance

Maximum speed: 204 km/h (127 mph, 110 kn) at sea level
Cruise speed: 187 km/h (116 mph, 101 kn) at 3,000 ft (914 m)
Service ceiling: 4,900 m (16,200 ft)
Rate of climb: 3.34 m/s (657 ft/min)
Rate of climb on one engine: 0.3 m/s (59 ft/min)
Take-off run: 260 ft (79 m) minimum
Take-off distance to 15 m (49 ft): 590 m (1,940 ft)

References

^ ^a ^b LAMBERT, C. M. (6 June 1958). "Foretaste of the Caravan HDM.105 HANDLING AND HDM.106 PROSPECTS". Flight and Aircraft Engineer. 73 (2576): 776–777.
^ ^a ^b ^c ^d ^e ^f Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 354–356. ISBN 0-370-00127-3.
^ Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 356–357. ISBN 0-370-00127-3.
^ ^a ^b Bridgman, Leonard, ed. (1957). Jane's All the World's Aircraft 1958-59. London: Jane's All the World's Aircraft Publishing Co. Ltd. pp. 95–96.

[Flight060658p776-1] LAMBERT, C. M. (6 June 1958). "Foretaste of the Caravan HDM.105 HANDLING AND HDM.106 PROSPECTS". Flight and Aircraft Engineer. 73 (2576): 776–777.

[Brown-2] ^ ^a ^b ^c ^d ^e ^f Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 354–356. ISBN 0-370-00127-3.

[Brown2-3] Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 356–357. ISBN 0-370-00127-3.

[JAWA58-59-4] Bridgman, Leonard, ed. (1957). Jane's All the World's Aircraft 1958-59. London: Jane's All the World's Aircraft Publishing Co. Ltd. pp. 95–96.

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