de Havilland Albatross
|The prototype DH.91 Albatross, G-AEVV, over Hatfield, September 1938 (photo from Flight International)|
|Role||Mail plane and transport aircraft|
|Designer||A. E. Hagg|
|First flight||20 May 1937|
|Primary users||Imperial Airways/British Overseas Airways Corporation|
Royal Air Force
|Number built||7 (including two prototypes)|
The de Havilland DH.91 Albatross was a four-engine British transport aircraft in the 1930s. A total of seven aircraft were built in 1938–39.
The aircraft was notable for the ply-balsa-ply sandwich construction of its fuselage, later used in the de Havilland Mosquito bomber. Another unique feature was a cooling system for the air-cooled engines that allowed nearly ideal streamlining of the engine mounting. The first Albatross flew on 20 May 1937. The second prototype broke in two during overload tests but was repaired with minor reinforcement. The first and second prototypes were operated by Imperial Airways.
Although designed as a mailplane, a version to carry 22 passengers was developed; the main differences being extra windows and the replacement of split flaps with slotted flaps. Five examples formed the production order delivered in 1938/1939. When war was declared all seven aircraft were operating from Bristol/Whitchurch to Lisbon and Shannon.
As normal for the Imperial Airways fleet of the time, all were given names starting with the same letter, and the first aircraft's name was also used as a generic description for the type overall, as "Frobisher Class". This tradition, which came from a maritime and railway background of classes of ships and locomotives, lasted well into postwar days with BOAC and BEA.
The first delivery to Imperial Airways was the 22-passenger DH.91 Frobisher in October 1938. The five passenger-carrying aircraft were operated on routes from Croydon to Paris, Brussels and Zurich. After test flying was completed, the two prototypes were delivered to Imperial Airways as long-range mail carriers. The only significant season of their operation was the summer of 1939, when they were the main type on the two-hourly London Croydon-to-Paris Le Bourget passenger route.
With the onset of World War II, the Royal Air Force considered their range and speed useful for courier flights between Great Britain and Iceland, and the two mail planes were pressed into service with 271 Squadron in September 1940, operating between Prestwick and Reykjavik but both were destroyed in landing accidents in Reykjavík within the space of 9 months: Faraday in 1941 and Franklin in 1942.
Frobisher was destroyed during a German air raid on Whitchurch in 1940,[a], Fingal was destroyed in a crash landing following a fuel pipe failure in 1940 at Pucklechurch and Fortuna crashed near Shannon Airport in 1943. The latter accident was found to be due to deterioration of the aircraft's plywood wing structures. In view of the two surviving aircraft's vulnerability to similar problems, and for lack of spares parts, Falcon and Fiona were scrapped in September 1943.
- Mail-carrier variant was delivered to Imperial Airways in August 1939 as Faraday and registered G-AEVV. It was transferred to BOAC when it was formed in 1940 but was impressed into Royal Air Force service with serial number AX903 for operation by No. 271 Squadron RAF. It was destroyed in a landing accident at Reykjavik on 11 August 1941.
- Mail-carrier variant was delivered to BOAC as Franklin and registered G-AEVW. Impressed into Royal Air Force Service with the serial number AX904 for operation by 271 Squadron. It was destroyed when the landing gear collapsed on landing at Reykjavik on 7 April 1942.
- Passenger variant was registered G-AFDI and delivered to Imperial Airways (later BOAC) as Frobisher in 1938. It was destroyed on the ground during a German air attack on Whitchurch Airport on 20 December 1940.
- Passenger variant was registered G-AFDJ and delivered to Imperial Airways (later BOAC) as Falcon in 1938. It was scrapped in September 1943.
- Passenger variant was registered G-AFDK and delivered to Imperial Airways (later BOAC) as Fortuna in 1939. Destroyed in a crash landing near Shannon Airport, Ireland on 16 July 1943.
- Passenger variant was registered G-AFDL and delivered to Imperial Airways (later BOAC) as Fingal in 1939. Destroyed in a crash landing near Pucklechurch, Gloucestershire, England on 6 October 1940.
- Passenger variant was registered G-AFDM and delivered to Imperial Airways (later BOAC) as Fiona in 1939. It was scrapped in September 1943.
A 1/10 scale model of the Albatross owned by British Airways was found in a crate at Croydon in the 1990s and is on display in the heritage museum at Speedbird House.
- Imperial Airways which was reorganised as British Overseas Airways Corporation received all seven aircraft.
- Royal Air Force
- No. 271 Squadron RAF operated two aircraft taken over from BOAC.
- Crew: 4 (pilot, copilot, radio operator and steward(ess))
- Capacity: 22-30 passengers
- Length: 71 ft 7 in (21.83 m)
- Wingspan: 105 ft 0 in (32.01 m)
- Height: 22 ft 3 in (6.78 m)
- Wing area: 1,077.9 sq ft (100.14 m2)
- Airfoil: RAF-34 mod
- Empty weight: 21,300 lb (9,662 kg)
- Max takeoff weight: 29,500 lb (13,381 kg)
- Fuel capacity: airliner 440 imp gal (528 US gal; 2,000 l) in two under-belly tanks ; mailplane 1,320 imp gal (1,585 US gal; 6,001 l) in four main cabin fuel tanks
- Powerplant: 4 × de Havilland Gipsy Twelve V-12 air-cooled inverted geared and supercharged piston engines, 415 hp (309 kW) each at 2450 rpm at 8,000 ft (2,438 m)
- 510 hp (380 kW) at 2,600 rpm for take-off
- Propellers: 2-bladed de Havilland constant-speed propellers
- Maximum speed: 225 mph (362 km/h, 196 kn)
- Cruise speed: 210 mph (340 km/h, 180 kn) with 77% power at 11,000 ft (3,353 m)
- 193.5 mph (168 kn; 311 km/h)with 65% power at 11,000 ft (3,353 m)
- 200 mph (174 kn; 322 km/h)with 65% power at 15,000 ft (4,572 m)
- Range: 1,070 mi (1,720 km, 930 nmi) in still with maximum fuel
- Service ceiling: 18,700 ft (5,700 m)
- Absolute ceiling: 20,500 ft (6,248 m)
- Absolute ceiling on one engine: 12,300 ft (3,749 m)
- Rate of climb: 1,018 ft/min (5.17 m/s)
- Time to altitude:
- 5,000 ft (1,524 m) in 7 minutes
- 10,000 ft (3,048 m) in 14 minutes
- 15,000 ft (4,572 m) in 26 minutes
- Wing loading: 27.4 lb/sq ft (134 kg/m2)
- Power/mass: 0.0719 hp/lb (0.1182 kW/kg)
- Moss states that Frobisher was actually destroyed by an arson attack by a disgruntled ex-BOAC employee on 20 October 1940.
- Bonnier Corporation (September 1938). "Cooling System for Plane Engines Uses Air Piped from Wings". Popular Science. Bonnier Corporation. p. 46.
- Mondey, Dvaid (1982). Hamlyn Concise Guide to British Aircraft of World War II. Hamlyn Publishing Group Ltd. p. 75. ISBN 1851526684.
- Moss Air Pictorial, September 1964, p. 292.
- Moss Air Pictorial September 1964, p. 293.
- Moss Air Pictorial, September 1964, p. 294.
- Jackson 1973, pp 472
- Civil Aviation Authority Registration Entry for G-AEVV Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AEVW Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AFDI Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AFDJ Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AFDK Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AFDL Archived 6 June 2011 at the Wayback Machine
- Civil Aviation Authority Registration Entry for G-AFDM Archived 6 June 2011 at the Wayback Machine
- Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's All the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. pp. 32c–34c.
- Jackson 1973, p.153.
- Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
|Wikimedia Commons has media related to De Havilland DH.91 Albatross.|
- Kopenhagen, Wolfgang (editor) (1987). Das große Flugzeug-Typenbuch. Transpress. ISBN 3-344-00162-0.CS1 maint: extra text: authors list (link)
- Jackson, A. J. (1987). De Havilland aircraft since 1909. Naval Institute Press. ISBN 0-87021-896-4.
- Jackson, A. J. (1973). British Civil Aircraft since 1919, Volume 2 (2nd ed.). Putnam. ISBN 0-370-10010-7.
- Moss, Peter W. (September 1964). "The de Havilland D.H.91 Albatross". Air Pictorial. Vol. 26 no. 9. pp. 292–294.