Hurel-Dubois Miles HDM.105

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.

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

Design and development

Maurice Hurel, 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 Societe des Avions Hurel-Dubois, 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.

H.D.M. 106 and 107 Project particulars

Dimensions and weights:[2]

Span 75 ft 4 in (23.0 m); length 37 ft 10 in (11.5 m); height 11 ft 5 in (3.5 m); aspect ratio 20·3; wing area 279 sq ft (25.9 m2); freight volume 563 cu ft (15.9 m3)
Weight empty 4,940 lb (2,240.7 kg); fuel 155 imp gal (186 US gal; 700 l) / 1,240 lb (562.5 kg) (max fuel 300 imp gal (360 US gal; 1,400 l)); crew 320 lb (145.1 kg); payload 3,000 lb (1,360.8 kg);
all up weight 9,500 lb (4,309.1 kg).

Performance at 8,000 lb (3,628.7 kg) all up weight with GSO-480B engines:[2]

cruising speed 132 mph (115 kn; 212 km/h) at 5,000 ft (1,524 m) on 50% power.
Run to unstick - 705 ft (215 m); distance to 50 ft (15 m) - 1,485 ft (453 m); landing from 50 ft (15 m) - 1,095 ft (334 m)
Rate of climb at sea-level 1,560 ft/min (7.9 m/s) on two engines, 410 ft/min (2.1 m/s) on one engine;
service ceiling 24,700 ft (7,529 m).

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: 127 km/h (79 mph, 69 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
  1. LAMBERT, C. M. (6 June 1958). "Foretaste of the Caravan HDM.105 HANDLING AND HDM.106 PROSPECTS". Flight and Aircraft Engineer. Vol 73 (No 2576): p.p.776-777.
  2. Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 354–356. ISBN 0-370-00127-3.
  3. Brown, Don L. (1970). Miles Aircraft since 1925 (1st ed.). London: Putnam & Company Ltd. pp. 356–357. ISBN 0-370-00127-3.
  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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