de Havilland Express
D.H.86 Express | |
---|---|
A D.H.86 air ambulance of the RAAF | |
Role | Passenger transport / trainer |
Manufacturer | de Havilland |
First flight | 14 January 1934 |
Introduction | 1934 |
Primary users | Imperial Airways Qantas Royal Air Force Royal Australian Air Force |
Produced | 1934–1937 |
Number built | 62 |
The de Havilland Express, also known as the de Havilland D.H.86, was a four-engined passenger aircraft manufactured by the
Development
During 1933, talks between the governments of United Kingdom, India, Malaya, the Straits Settlements and Australia resulted in an agreement to establish an Empire Air Mail Service. The Australian Government called for tenders on 22 September 1933 for the Singapore-Australia legs of the route, continuing as far south as Tasmania. On the following day Qantas, anticipating success in contracting for the Singapore-Brisbane leg, placed an order with de Havilland for an as-yet non-existent aircraft to be designated the de Havilland 86, the prototype to fly by the end of January 1934. This order was soon followed by one from Holyman's Airways of Launceston, Tasmania to operate the Bass Strait leg of the service. The D.H.86 was initially styled the Express or Express Air Liner, although the name was soon discontinued.
The D.H.86 was conceptually a four-engined enlargement of the successful
The prototype D.H.86 first flew on 14 January 1934, but the
Investigations in 1936 following a series of fatal crashes resulted in late production aircraft being built with additional fin area in the shape of vertical "Zulu Shield" extensions to the tail planes to improve lateral stability – these aircraft were designated D.H.86B.
Operational history
Early proving flights were flown in 1934 by
Dual-pilot D.H.86s were built for Imperial Airways and given the class name Diana. They were used on European and Empire air routes including the run from Khartoum to Lagos.
Railway Air Services (RAS) operated a fleet of seven Expresses between 1934 and 1946. RAS used the aircraft on their UK scheduled flight network including their trunk route from London Croydon via Birmingham, Manchester/Liverpool to Glasgow.
D.H.86s were also built for New Zealand's Union Airways, flying between Auckland, Palmerston North and Wellington. During World War II, the New Zealand aircraft were fitted with bomb racks and used by the Royal New Zealand Air Force to hunt German raiders and Japanese shipping. The survivors served with New Zealand National Airways Corporation (NAC) post war.
A total of 15 D.H.86s, D.H.86As and D.H.86Bs operated commercially within Australia and New Guinea up to the outbreak of World War II. Eight D.H.86A and D.H.86B aircraft were impressed into the Royal Australian Air Force and served as A31-1 to A31-8 during the War. Some served as air ambulances in the Middle East, while others did sterling work as transport aircraft and air ambulances in Australia and New Guinea.[2]
A total of 62 D.H.86s of all types were built. Most of those still flying in Europe at start of World War II, except for the Railway Air Services aircraft, were taken into military service, mostly for communications and radio navigational training. A few Expresses survived the war and were used by UK air charter operators until the last example was burnt out in 1958.
Technical deficiencies
Seriously lacking in directional stability, the D.H.86s were frequently in trouble. On 19 October 1934 Holyman's VH-URN Miss Hobart was lost in
On 2 October 1935 Holyman's VH-URT Loina was also lost in Bass Strait, again with no survivors. This time a significant amount of wreckage was recovered from the sea and from beaches on Flinders Island. Investigation of the wreckage revealed a section of charred carpet on a piece of cabin flooring from just ahead of the lavatory door. It was thought possible that a small fire from a dropped cigarette had led to someone running aft suddenly to stamp it out – a sudden change in weight distribution that could lead to fatal loss of directional control while the aircraft was on a low-speed landing approach.
On 13 December 1935, another Holyman DH86, Lepina, forced-landed on Hunter Island off northern Tasmania with the lower port interplane strut having "vibrated loose". An investigation by the Australian Civil Aviation Board using stop-motion film of the wing in flight resulted in identification of wing distortion and failure under certain flight conditions. Australian authorities in December 1935 required the installation on all Australian DH86 aircraft of a complete set of lift bracing in the wing rear spar and redesign of the bracing on the tail unit to provide greater redundancy.[4]
The Royal Air Force's Aeroplane and Armament Experimental Establishment tested the D.H.86A design in 1936 following three fatal crashes in Europe. It would be forty years before the report was published. The D.H.86 had been rushed from design concept to test flight in a record four months to meet the deadlines set by the Australian airmail contracts, and a lot of attention to detail had been ignored. It was a big aircraft for its power, and as a result very lightly built. There was poor response to control movements in certain speed ranges, the wings were inclined to twist badly if the ailerons were used coarsely and, most seriously, the vertical tail surface was of inadequate area. The result was an aircraft that, although quite safe under normal conditions, could rapidly get out of control under certain flight regimes.
Although the control problems were overcome on later-manufactured D.H.86Bs by the fitting of a new spring in the elevator control and the fitting of auxiliary fins, the results of these tests do not appear to have been communicated to Australia and the D.H.86s already in use were never modified in this way to improve their safety. This lack of communication may have caused a number of later accidents, including at least one of two further fatal disasters in commercial service. The mid-air break-up of Qantas' VH-USE Sydney in a thunderstorm near Brisbane on 20 February 1942 with the loss of nine lives, was possibly unavoidable; however, the fin was found almost a mile away from the main wreckage which had been burnt. The accident involving MacRobertson Miller Airlines’ ex-Qantas aircraft VH-USF at Geraldton on 24 June 1945 most likely was entirely avoidable had the AaAEE report been communicated to Australia.[5] On its first commercial flight for its new owners after military service, the pilot and a passenger were killed in a classic loss-of-control accident while taking off with a heavy load in gusty conditions.
Another D.H.86, VH-USW (the former Holyman's Airways Lepena), was bought by MacRobertson Miller Airlines at much the same time as VH-USF and was the last of the type to fly in Australia. MMA sold the eleven-year-old aircraft to an English company late in 1946; it was abandoned in India in an "unsafe state" while on its delivery flight. Edgar Johnston, the Assistant Director General of the Australian Department of Civil Aviation, then had it scrapped at Australian Government expense to make sure that it never flew again.[6][7]
Political and commercial consequences
Following the first three fatal Australian D.H.86 accidents, and a forced landing by VH-USW Lepena on 13 December 1935 when the pilot believed his aircraft was about to break up in mid-air,
Other accidents and incidents
- On 12 August 1936 G-ADEB of British Airways crashed near Altenkirchen, Germany.
- On 15 September 1936 G-ADYF of British Airways crashed during a night take off from Gatwick Airport, England.
- On the night of 15/16 March 1937 G-ACVZ Jupiter of Railway Air Services, carrying Charles Wolley-Dod, crashed at Elsdorf near Cologne, Germany.[9]
- On 9 May 1938, G-AENR of Speke Airport, Liverpool, Lancashire. Despite substantial damage to the port lower wing and both port engines, the aircraft was repaired and returned to service.[10]
- On 14 September 1938, G-ADVK of Isle of Man Air Services lost the starboard inner propeller in flight whilst operating a flight from Speke to Ronaldsway. The propeller embedded itself in the fuselage of the aircraft. A successful landing was made at Ronaldsway.[11]
- 4 November 1938: DH.86 G-ACZN St. Catherine's Bay crashed at St. Peter's shortly after take-off from Jersey airport, en route to Southampton. All 13 occupants were killed in addition to one person on the ground.[12]
Variants
- D.H.86
- Four-engined medium-transport biplane. First production version, 32 built, the first four with a single-pilot cockpit.
- D.H.86A
- Improved version with pneumatic landing gear, metal rudder and modified widescreen. 20 built, all converted to DH.86B standard.
- D.H.86B
- Fitted with auxiliary "Zulu-Shield" endplate fins to the tailplane. 10 built.
Operators
♠ Original operators
Civil operators
- Australian National Airways[1]
- Holyman's Airways[1]♠
- MacRobertson Miller Airlines[1]
- Qantas[1] ♠
- W.R. Carpenter[1] ♠
- Misr Airwork[1]♠
- Tata Airlines[1]
- Wearne Brothers Limited.[1]
- Turkish Airlines Turkish State Airlines (Devlet Hava Yollari) [1]♠
- Allied Airways[1] ♠
- Blackpool and West Coast Air Services[1]♠
- British Airways[1] ♠
- Hillman's Airways[14]
- Imperial Airways[1] ♠
- Jersey Airways[1] ♠
- Lancashire Aircraft Corporation[1]
- Peacock Air Charter[1]
- Railway Air Services[1] ♠
- Skytravel[1]
- Western Airways[1]
- Wrightways[1]
Military operators
Specifications (D.H.86A)
Data from De Havilland Aircraft since 1909,[15] Jane's All the World's Aircraft 1938[16]
General characteristics
- Crew: 2 (pilot and co-pilot)
- Capacity: 10–16 passengers
- Length: 46 ft 1.25 in (14.0526 m)
- Wingspan: 64 ft 6 in (19.66 m)
- Height: 13 ft 0 in (3.96 m)
- Wing area: 641 sq ft (59.6 m2)
- Aspect ratio: 12.3
- Airfoil: RAF 34 modified[17]
- Empty weight: 6,140 lb (2,785 kg)
- Gross weight: 10,250 lb (4,649 kg)
- Fuel capacity: 1,145 imp gal (1,375 US gal; 5,205 L) in two undercarriage fairing tanks
- Powerplant: 4 × de Havilland Gipsy Six I6-cylinder air-cooled inverted in-line piston engines, 200 hp (150 kW) each
- Propellers: 2-bladed fixed-pitch propellers
Performance
- Maximum speed: 166 mph (267 km/h, 144 kn) at sea level
- Cruise speed: 142 mph (229 km/h, 123 kn) at 1,000 ft (305 m)
- Range: 760 mi (1,220 km, 660 nmi)
- Service ceiling: 17,400 ft (5,300 m)
- Absolute ceiling: 19,500 ft (5,944 m)
- Absolute ceiling with one engine inoperative: 13,000 ft (3,962 m)
- Absolute ceiling with two engines inoperative: 2,000–4,000 ft (610–1,219 m) depending on combination
- Rate of climb: 925 ft/min (4.70 m/s)
- Time to altitude:
- 5,000 ft (1,524 m) in 6 minutes 30 seconds
- 10,000 ft (3,048 m) in 15 minutes
See also
Related development
Related lists
Notes
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af Jackson 1987, pp. 341–350
- ^ ADF Serials D.H.86 page Archived 11 November 2007 at the Wayback Machine retrieved on 2007-09-13.
- ^ This section is largely sourced from the book Air Crash, Volume One by Macarthur Job. Job, Macarthur (1991). Air Crash, Volume One (1991 ed.). Canberra: Aerospace Publications.
- ^ P Ewer, ':Wounded Eagle, New Holland Sydney 2009 p.74
- ^ Air Crash Vol. II pp107-111.
- ^ Air Crash Vol. II p111.
- ^ The Historic Civil Aircraft Register of Australia VH-USW entry.
- ^ It was later found that only a metal fairing had worked loose and was fluttering in the airflow, but this incident demonstrates the lack of confidence in the design held within the Australian aviation industry at the time.[citation needed]
- ^ "Disaster in Germany; discovery by woodcutter". Croydon Times. 20 March 1937. p. 1 – via British Newspaper Archive.
- ^ Poole 1999, pp. 14–15.
- ^ Poole 1999, p. 15.
- ^ Air disaster of 1938
- ISBN 0-7864-0495-7. Retrieved 17 January 2010.
- ^ Arthur 1992, p. 23
- ^ Jackson 1987, p. 347
- ^ Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's All the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. pp. 30c–31c.
- ^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
Bibliography
- Arthur, Robin (1992). "Pre-War Airliner Fleets: I. Hillman's Airways Ltd". Archive. No. 1. ISSN 0262-4923.
- Comas, Matthieu (September–October 2020). "So British!: 1939–1940, les avions britanniques dans l'Armée de l'Air" [So British!: British Aircraft in the French Air Force 1939–1940]. Avions (in French) (236): 38–61. ISSN 1243-8650.
- Cookson, Bert. The Historic Civil Aircraft Register of Australia (Pre War) G-AUAA to VH-UZZ. 1996, Toombul, Queensland: AustairData (privately published).
- Jackson, A. J. (1988). British Civil Aircraft 1919–1972: Volume II (1988 ed.). London: Putnam (Conway Maritime Press).
- Jackson, A.J (1987). De Havilland Aircraft since 1909. London: Putnam. ISBN 0-85177-802-X.
- Job, Macarthur (1992). Air Crash, Volume Two (1992 ed.). Canberra: Aerospace Publications.
- Lumsden, Alec; Heffernan, Terry (April 1984). "Probe Probare: No. 3: D.H. 86". Aeroplane Monthly. Vol. 12, no. 4. pp. 180–185.
- Prins, François (Spring 1994). "Pioneering Spirit: The QANTAS Story". ISSN 0143-5450.
- Poole, Stephen (1999). Rough Landing or Fatal Flight. Douglas: Amulree Publications. ISBN 1-901508-03-X.