One of the largest aircraft of its time, it had the range to cross the Atlantic and Pacific oceans. For its wing, Boeing re-used the design from their earlier XB-15 bomber prototype. Twelve Clippers were built, nine of which served with Pan Am. Pan American had requested a flying boat with unprecedented range that could augment the airline's trans-Pacific Martin M-130. Boeing's bid was successful and on July 21, 1936, Pan American signed a contract for six. Boeing engineers adapted the cancelled XB-15's 149 ft (45 m) wing, and replaced the 850 hp (630 kW) Pratt & Whitney Twin Wasp radial engines with the 1,600 hp (1,200 kW) Wright Twin Cyclone.[1] Pan Am ordered six more aircraft with increased engine power and capacity for 77 daytime passengers as the Boeing 314A. The huge flying boat was assembled at Boeing's Plant 1 on the Duwamish River in Seattle, and towed to Elliott Bay for taxi and flight tests. The first flight was on June 7, 1938, piloted by Edmund T. "Eddie" Allen. At first the aircraft had a single vertical tail, and Allen found he had inadequate directional control. The aircraft returned to the factory and was fitted with the endplates on the ends of the horizontal tail in place of the single vertical fin. This too was found to be insufficient and finally the centerline vertical fin was restored, after which the aircraft flew satisfactorily. Pan Am's "Clippers" were built for "one-class" luxury air travel, a necessity given the long duration of transoceanic flights. The seats could be converted into 36 bunks for overnight accommodation; with a cruising speed of 188 miles per hour (303 km/h) (typically flights at maximum gross weight were flown at 155 miles per hour (249 km/h)) in 1940, Pan Am's schedule San Francisco to Honolulu was 19 hours. The 314s had a lounge and dining area, and the galleys were crewed by chefs from four-star hotels. For more details of the Clipper, click here.
