de Havilland DH.91 Albatross
The de Havilland DH.91 Albatross was a four-engined British wooden airliner of the 1930s, designed to an Air Ministry specification for a transatlantic mailplane. Just seven were built: two mailplane prototypes and five production aircraft seating 22 passengers. First flown in May 1937, the type entered Imperial Airways service in 1938–39, set inter-city speed records, and flew wartime routes from Bristol to Lisbon and Shannon while the RAF used the two mailplanes on the Iceland run. Accidents and an air raid reduced the fleet steadily, and after a July 1943 crash was traced to deterioration of the plywood wing structure, the last two aircraft were scrapped that September; none survives.
Why It Mattered
The Albatross began as de Havilland's own response to American competition: its Comet racer won the 1934 MacRobertson race to Australia, with the Douglas DC-2 close behind it. The company concluded that it needed far faster passenger aircraft to compete with the Americans, and it sought Air Ministry support. On 21 January 1936 it received a contract for two transatlantic mailplanes to specification 36/35, specified to haul 1,000 lb of cargo across 2,500 miles at 210 mph against a 40 mph headwind. Production stopped at seven aircraft: two prototypes and five production machines. The type's lasting importance is its wooden construction, which gave de Havilland experience that proved invaluable in the Mosquito.
Design Notes
A. E. Hagg designed the DH.91 in 1936 to Air Ministry specification 36/35, as a transatlantic mailplane. Its fuselage was a ply-balsa-ply sandwich, a form of construction later used in the Mosquito. History of War describes the structure as layers of cedar and balsa wood, and the aircraft itself as elegant and slender. Power came from four Gipsy Twelve engines of 525 hp, which History of War says de Havilland created for the type by combining two Gipsy Six engines. Wikipedia also records an engine cooling arrangement designed to keep the mountings nearly ideally streamlined. The five production aircraft seated 22 passengers and differed from the mailplane prototypes in their extra windows and slotted flaps, which replaced split flaps.
Operational History
The first Albatross flew on 20 May 1937. During overload tests the second prototype broke in two; minor reinforcement repaired it. Wikipedia dates the first delivery, the 22-passenger Frobisher, to October 1938, while History of War gives 2 January 1939 for the passenger aircraft entering service. The passenger aircraft flew from Croydon to Paris, Brussels and Zurich. In the last months of peace the type broke inter-city speed records, including a 48-minute London to Brussels flight. Through the summer of 1939 it was the main type on the Croydon to Paris Le Bourget route. At the outbreak of war all seven aircraft moved to Whitchurch, Bristol, and flew on to Shannon and Lisbon. In September 1940 the RAF took over the two longer-range mailplanes for No. 271 Squadron, on the Prestwick to Reykjavík run. Both mailplanes were destroyed in landing accidents at Reykjavík, one in 1941 and one in 1942. One passenger aircraft was destroyed in a forced landing at Pucklechurch in October 1940, and another in a German air raid that December. The remaining aircraft kept flying the long-range passenger routes until one crashed near Shannon in July 1943.
Afterlife
The last two aircraft, Falcon and Fiona, were scrapped in September 1943. Wikipedia traces the ending partly to the structure: the Shannon crash was blamed on deterioration of the plywood wing structure, the survivors were thought vulnerable to the same problem, and History of War adds a lack of spares. All seven airframes are accounted for: five destroyed by accidents or enemy action, and the final pair scrapped. A 1/10-scale model owned by British Airways, found in a crate at Croydon in the 1990s, is on display at the Speedbird House heritage museum. Its longer legacy was the wooden-aircraft experience de Havilland carried into the Mosquito.