BOEING 314 CLIPPER
Jagriti Srivastava
Role: Flying boat airliner
Manufacturer: Boeing Airplane Company
First flight: June 7, 1938
Introduction: 1939
Retired: 1946
Primary users: Pan American World Airways British Overseas Airways Corporation United States Navy
Produced : 1938–1941
Number built: 12
Developed from: Boeing XB-15 (used wing only)The Boeing 314 Clipper was a long-range flying boat produced by the Boeing Airplane Company between 1938 and 1941. One of the largest aircraft of the time, it used the massive wing of Boeing’s earlier XB-15 bomber prototype to achieve the range necessary for flights across the Atlantic and Pacific Oceans. Twelve Clippers were built for Pan Am. Three of them were sold to BOAC during the Battle of Britain (1940) and delivered in early 1941. (BOAC's 3 ShortS.26 transoceanic flying-boats had been requisitioned by the RAF).
DESIGN AND DEVELOPMENT:
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 B-15's 149 feet (45 m) wing, and replaced the 850 horsepower (630 kW) Pratt & Whitney Twin Wasp radial engines with the 1,600 horsepower (1,200 kW) Wright Twin Cyclone.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 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 fitted with the endplates on the ends of the horizontal tail in place of the single vertical fin. This too was found to be lacking and finally the centerline vertical fin was restored, after which the aircraft flew satisfactorily.The 314 used a series of heavy ribs and spars to create a robust fuselage and cantilevered wing, obviating the need for external drag-inducing struts to brace the wings. Boeing also incorporated Dornier-style sponsons into the hull structure.The sponsons, broad lateral extensions at the water line on both sides of the hull, served several purposes: they provided a wide platform to stabilize the craft while floating on water, they acted as an entry way for passengers boarding the flying boat and they were shaped to contribute additional lift in flight. With weight an extremely sensitive concern, passengers and their baggage were weighed, with each passenger allowed up to 77 pounds (35 kg) free baggage allowance (in the later 314 series) but then charged $3.25 per lb ($7.15/kg) for exceeding the limit.To fly the long ranges needed for trans-Pacific service, the 314 carried 4,246 US gallons (16,070 l; 3,536 imp gal) of gasoline. The later 314A model carried a further 1,200 US gallons (4,500 l; 1,000 imp gal). To quench the radial engines’ thirst for oil, a capacity of 300 US gallons (1,100 l; 250 imp gal) was required.
VARIANTS:
Model 314
Initial production version with 1,500 horsepower (1,100 kW) Twin Cyclone engines, six built
Model 314A
Improved version with 1,600 horsepower (1,200 kW) Twin Cyclones with larger-diameter propellers, additional 1,200 US gallons (4,500 l; 1,000 imp gal) fuel capacity, and revised interior. Still air range approx 4,700 miles six built
B-314
Five Model 314s impressed into military service with the U.S. Navy
C-98
Four Model 314s impressed into military service with the U.S. Army Air Forces
Model 306
A concept aircraft using a Model 314 fuselage with a tailless delta-wing planform. No examples built.
OPERATORS
United States: Pan American World Airways United States Army Air Forces United States Navy
United Kingdom: British Overseas Airways Corporation Survivors
SPECIFICATIONS
General characteristics
Crew: 11, including 2 cabin stewards
Capacity: Daytime: 74 passengers, Nighttime: 36 passengers
Payload: 10,000 lb (4,500 kg) of mail and cargo
Length: 106 ft (32.33 m)
Wingspan: 152 ft (46.36 m)
Height: 20 ft 4½ in (6.22 m)
Empty weight: 48,400 lb (21,900 kg)
Loaded weight: 84,000 lb (38,000 kg)
Powerplant: 4 × Wright R-2600 -3 radial engines, 1,600 hp (1,200 kW) each
PERFORMANCE:
Maximum speed: 210 mph (180 knots, 340 km/h)
Cruise speed: 188 mph (163 knots, 302 km/h) at 11,000 ft (3,400 m)
Range: 3,685 mi (3,201 nm, 5,896 km) normal cruise
Service ceiling: 19,600 ft (5,980 m)
BOEING 314 CLIPPER-USA:
When the Boeing 314 flying boat made its appearance, it was the largest civil aircraft in service. Shown above is the California Clipper.
The Yankee Clipper project dated back to 1935, with the start of a series of negotiations between Pan American World Airways and Boeing for the production of a flying-boat capable of guaranteeing transatlantic passenger flights with a high degree of safety, comfort, and speed.1 On July 21,1936, Pan American signed a contract for six aircraft, the first of which (designation Model 314) made initial see runs on Puget Sound on May 31,1938, and took to the air on June 7, 1938. 2 When it made its appearance this flying-boat was the largest civil aircraft in service.
It outstripped all rivals in size, with twice the size of the Sikorsky S-42 and outweighed the Martin M-130 China Clipper by 15 tons.3 The 14-cylinder double-row Wright Cyclones were the first to use 100-octane fuel. The Boeing 314, the finest flying boat to go into regular commercial service, weighed 40 tons, and the first batch cost $550,000 per aircraft.
It had a central hull and adopted the wing and engine assembly of the experimental Boeing XB-15 4 heavy bomber. In the place of the traditional floating stabilizers at the wingtips, sponsons mounted on the sides of the hull were used. The sponsons were based on the formula developed by the German engineer Claude Dornier and incorporated into such aircraft as the Dornier Do X and Dornier Do 18. The sponsons also contained fuel tanks, the capacity of which (together with those situated in the wings) totaled almost 3,525 gallons (16,000 liters).
CALIFORNIA CLIPPER:
Mechanics performing maintenance repairs on the California Clipper. The number on the center vertical stabilizer is No 18 and the number on the left hand vertical stabilizer is NC 18602.
At first, Boeing had problems with the single vertical stabilizer, which resulted in inadequate directional control. It tried a twin-tail arrangement, and finally settled on the three fins which became a feature of the design. In the spacious fuselage there was ample room for 74 daytime passengers, or for 40 passengers in reclining seats for long night-flights.
On May 20,1939, Pan American inaugurated the first transatlantic mail service. Under the command of Captain A. E. LaPorte, almost a ton of mail was carried from Port Washington to Marseilles, via the Azores and Lisbon in 29 hours. The same aircraft, commanded by Captain Harold Gray, opened the northern mail service to Southampton on June 24,1939.
On June 28,1939, Pan American inaugurated the first regular passenger service from New York to Southampton, via Newfoundland. Under the command of Captain R.0.D. Sullivan, the "Dixie Clipper" carried the first scheduled passengers across the North Atlantic. Twenty-two privileged persons had the option of paying $375 one-way (about $4,000 in today's money) or $675 return (say about $7,000 or $8,000, or twice Concorde levels). The Yankee Clipper opened the northern passenger route on July 8,1939, carrying 17 passengers at the same fare. Today, the North Atlantic route is still the most prestigious of all today despite the immense growth of the airlines.
The golden age of the commercial flying-boats was abruptly interrupted by the outbreak of the Second World War in Europe on September 3,1939. The war curtailed Pan American's opportunity to build on its success and the northern transatlantic route was abandoned after only three months on October 3,1939.
With the success of the Boeing 314, Pan American ordered another six aircraft with the designation Boeing 314A. The 314A was considerably improved—it had a carrying capacity of 77 daytime passengers, increased engine power, and increased fuel capacity of nearly 1,000 gallons (4,500 liters). The first of the Boeing 314A aircraft flew as a prototype on March 20, 1941, but with WW II in full swing, only half the order went to Pan American. Three models were bought by the British government and allotted to BOAC for use as transport aircraft.
ATLANTIC CLIPPER:
The number on the left hand vertical stabilizer is NC 18604.
Subsequently, the Boeing 314s continued flying all over the globe, flying mostly the Atlantic crossing by the central route, or via Brazil and West Africa. They made many important flights during the war, in support of military operations as far afield as southeast Asia. The Boeing 314 airplanes were well known for the fact that they carried Winston Churchill on his intercontinental journeys, and survived the war to be returned to the United States in 1948.
The career of the Boeing 314s, five of which were purchased by the USAAF and the US Navy, was also a lengthy one. Apart from three which were destroyed in February 1943, November 1945 and October 1947, others remained with Pan American. With the progress made in developing long-range landplanes during WW II, the last Boeing 314 was retired from Pan American World Airways in 1946. They were then used by various small charter companies and not withdrawn from service until 1950.
Boeing 314 Aircraft Operated by Pan American World Airways
NUMBER TYPE NAME DATE
NC18601 Boeing 314 Honolulu Clipper - Sank by US Navy 1939-1945
NC18602 Boeing 314 California Clipper - Renamed Pacific Clipper Sold to World Airways 1939-1950
NC18603 Boeing 314 Yankee Clipper - Started Transatlantic mail service 1939-1943
NC18604 Boeing 314 Atlantic Clipper 1939-1946
NC18605 Boeing 314 Dixie Clipper - Started transatlantic passenger service 1939-1950
NC18606 Boeing 314 American Clipper 1939-1946
NC18609 Boeing 314A Pacific Clipper 1941-1946
NC18611 Boeing 314A Anzac Clipper 1941-1951
NC18612 Boeing 314A Capetown Clipper 1941-1946
SPECIFICATIONS:
Boeing 314A Yankee Clipper
DIMENSIONS
Wing span: 152 ft 0 in (46.33 m)
Length: 106 ft 0 in (32.31 m)
Height: 27 ft 7 in (8.41 m)
Wing Area: 2,867 sq ft (266.34 sq m)
Weights:
Empty: 50,268 lb (22,801 kg)
Gross T/O: 82,500 lb (37,422 kg)
PERFORMANCE
Maximum Level Speed: 199 mph (320 km/h)
Cruising Speed: 183 mph (294 km/h)
Service Ceiling: 13,400 ft (4,085 m)
Normal Range: 3,500 miles (5,633 km)
Powerplant: Four Wright GR-2600 Twin Cyclone, 1,600 hp (1,192 kw), 14 cylinder, air-cooled, radial engines.
Regards,
Jagriti Srivastava [B.Tech ]
Web Developer / Blog Master
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