As early as January 1935, Pan American Airways had signified to the US Bureau of Air Commerce its wish to establish a transatlantic service and, despite its ownership of the large Martin M-130 and Sikorsky S-42 long-range four-engined flying-boats, the airline wanted a new aircraft for the route.

Boeing submitted a successful tender to the Pan American specification and a contract for six Boeing Model 314 flying-boats was signed on 21 July 1936. The manufacturer used features of the earlier XB-15 heavy bomber, adapting the wing and horizontal tail surfaces for its 37421kg gross weight flying-boat, which could accommodate up to 74 passengers in four separate cabins. The engines were not the 746kW Pratt & Whitney R-1830 Twin Wasps of the XB-15, but 1119kW Wright GR-2600 Double Cyclones which gave the machine a maximum speed of 311km/h. The fuel capacity of 15898 litres conferred a maximum range of 5633km; some of the fuel was stored in the stabilising sponsons, which also served as loading platforms.

The first Boeing 314 took off on its maiden flight on 7 June 1939, this original version having a single fin and rudder, later replaced by twin tail surfaces to improve directional stability. These proved to be inadequate, and the original centreline fin was restored, without a movable rudder. The aircraft was awarded Approved Type Certificate No. 704 and entered transatlantic airmail service on 20 May 1939, passenger service commencing on 28 June. At that time the Model 314 was the largest production airliner in regular passenger service.

Pan American ordered another six aircraft which were designated Model 314A, improved by the installation of 1193kW Double Cyclones with larger-diameter propellers, and additional 4542 litres of fuel capacity, and a revised interior. The first Model 314A flew on 20 March 1941 and delivery was complete by 20 January 1942. Five of the original order were retrospectively converted to Model 314A standard in 1942. Three of the repeat order were sold, before delivery, to BOAC for transatlantic service and operation on the Foynes-Lagos sector of the wartime 'Horseshoe Route'.

Of Pan American's nine Model 314/ 314As, four were requisitioned by Army Transport Command and given the military designation C-98. They were little used, however, and in November 1942 one was returned to the airline. The other three were transferred to the US Navy to join two acquired direct from Pan American; the airline provided crews for the US Navy's B-314 operations and the aircraft were partially camouflaged but operated with civil registrations.

BOAC and Pan American terminated Boeing Model 314 services in 1946 and the surviving aircraft were sold to American charter airlines

3-View

A three-view drawing (1450 x 1040)