Boeing 314 Clipper

Background As early as 1935 Pan American had identified that a truly trans-Pacific flying boat with unprecedented range and double the passenger payload of the airline's Martin M-130 would be required particularly if they were to provide a service across the longer more difficult Atlantic route and requested proposals from a number of American manufacturers. In February 1936, not long after the M-130s were introduced into service, Pan American launched a design competition for the first transoceanic airliner. Boeing, Douglas, Consolidated, Martin and Sikorsky were requested to provide preliminary studies and proposals for a long-range, four engine, marine aircraft. The new plane had to be able to transport up to 10,000 pounds of payload with a minimum range of 2,400 miles and cruise speed of 150 mph at an altitude of 10,000 feet. Pan American was also adamant about providing comfort, space, and luxury for their passengers, as well as providing the ultimate in safety. Martin proposed a larger modified version of their M-130 called the M-156 which would offer a longer range and bigger payload with either a 53-day or 26 sleeper configuration. The deadline had passed when a young Boeing engineer, Wellwood E. Beall, became aware of the Pan American project, and thought that Boeing should consider submitting a bid. Beall had just returned to the United States in 1935 from serving as the company's Far Eastern manager with responsibility for selling the company's fighter and transport planes to the Chinese Government. During his time in China he had often thought about the design of a large flying boat and he now worked in his spare time on a preliminary design. Beall was transferred to the engineering department and allocated 11 engineers to work on the project. He combined the wing with more powerful Wright R-2600 Twin Cyclone engines, each of which produced 50% more power than the of the XB-15's Pratt & Whitney R-1830 Twin Wasp engines. The XB-15's engine nacelles were also retained, as they had originally been designed to house Allison V-3420 liquid-cooled W engines which, since these were not ready, had been replaced on the bomber by the smaller and less powerful Pratt & Whitneys. From here it commenced its first taxiing run on 3 June with test pilot Edmund T. Allen at the controls, but he soon identified that it was too lightly loaded when a gust of wind lifted one wing and dipped the other and after increasing the engine power failed to correct the situation it became necessary for all spare crew members to climb out onto the raised wing to balance the aircraft and allow it to safely return to shore. Following the installation of temporary ballast further taxiing tests continued for a week. He was only able to turn the aircraft by increasing the power of the engines on one wing and decreasing that of the engines on the other. This first flight lasted 38 minutes. NX-18601 was immediately modified into a twin fin configuration, but this was still found to be insufficient and so the centerline vertical fin was restored, which resolved the issue and this three fin arrangement became the production configuration. Months of extensive testing continued and on January 26, 1939, the 314 was approved the Civil Aeronautics Board for commercial airworthiness. ==Design==

The 314 was a high wing flying boat which used a series of heavy metal ribs and spars to create a robust fuselage and cantilevered wing, eliminating the need for external drag-inducing struts to brace the wings. It was metal skinned with the exception of the control surfaces. The aircraft were assembled at Boeing's Plant 1 on the Duwamish River in Seattle. The design required the production of 6,000 engineering drawings, 50,000 separate parts, 11 miles of electrical wiring, 576,000 rivets and 15,200 bolts. The other six 314A's had the more powerful Cyclone 14 GR2600A2A engines. The development of these propellers had been fostered by Pan American. In a first for commercial operation, these offered both variable pitch and full-feathering which meant that in the event of an engine fault the three blades of the diameter propellers could be turned directly into the airflow, and so would not rotate and risk further damaging the engine by “windmilling”. When installed in 1940, they featured the first NACA propeller aerofoil sections on a commercial aircraft. The 314 featured the first use of rate of flow fuel meters when they were installed in 1939 at the engineer's station as a permanent fitting on an aircraft. Previously they had been only installed as a temporary device during testing. Pan American had supported their development. Fuel capacity To fly the long ranges needed for trans-Pacific service, the 314 carried of gasoline. The later 314A model carried a further . A capacity of of oil was required for operation of the radial engines. Wings The wings were constructed in five sections of an aluminum outer skin formed over spars constructed out of bolted square aluminum alloy tube trusses while the ribs were formed out of aluminum alloy tubes and channels. They had a NACA 0018 airfoil profile at their root which changed to a NACA 0010 profile at their tip. The outer ends of the wings were made watertight, which allowed them to provide flotation if the aircraft heeled over in rough conditions. These sponsons, broad lateral extensions at the waterline on both sides of the hull, served several purposes: They provided a wide platform to stabilize the craft while on the water, they acted as a platform for boarding and exiting, and they possessed an intentional air foil shape which contributed additional aerodynamic lift in flight. Each was divided into five compartments, two of which were used as fuel tanks. Each sponson had sufficient reserve buoyancy to maintain stability if one of the compartments filled with water. At the rear of the compartment there were four tube and canvas bunks for the crew that folded up into the walls of the collision bulkhead. A separate cabinet held 350 Gorham sterling-silver "Moderen" pattern cutlery, a silver-plated tea set, and ten pairs of sterling salt and pepper shakers. Wherever possible, efforts were made to reduce weight. Duralumin was used in the furniture frames, and plastic in the portholes rather than glass. Lightweight carpet was used to assist in noise damping. The cushions were made of latex mixed with horsehair from Australia. Howard Ketcham, a color expert from New York assisted in the selection of colors that would complement Bel Geddes’ design and also reflect light, yet control brightness and create the impression of openness to reduce any feelings of claustrophobia. while a one-way ticket from San Francisco to Hong Kong via the "stepping-stone" islands cost $760 (). The Pan American Boeing 314 Clippers brought exotic destinations like the Far East within reach of air travelers and came to represent the romance of flight. Most of the flights were transpacific, while transatlantic flights to neutral Lisbon and Ireland continued after war broke out in Europe in September 1939 (and until 1945), but military passengers and cargoes necessarily got priority, and the service was more spartan. Crew Equally critical to the 314's success was the proficiency of its Pan American flight crews, who were extremely skilled at long-distance, over-water flight operations and navigation. For training, many of the transpacific flights carried a second crew. Only the very best and most experienced flight crews were assigned Boeing 314 flying boat duty. Before coming aboard, all Pan American captains as well as first and second officers had thousands of hours of flight time in other seaplanes and flying boats. Rigorous training in dead reckoning, timed turns, judging drift from sea current, celestial navigation, and radio navigation were conducted. In conditions of poor or no visibility, pilots sometimes made successful landings at fogged-in harbors by landing out to sea, then taxiing the 314 into port. The 314 normally had a crew of 10 but to address crew fatigue on long ocean flights the aircraft this could increase up to 16, divided into two shifts with a shift consisting of a pilot, co-pilot, navigator, radio operator, flight engineer, watch officer (also known as the "Master") and two stewards. Taking a year to design they each cost $10,000 and provided of working area equipped with work benches, telephones, compressed air, electricity supplies, floodlights, spare parts and on the lowest level, offices for the foreman and inspectors. At the end of the overhaul the aircraft would be subjected to a four-hour test flight. A 314 would typically spend two days between flights on an overhaul, which involved washing the aircraft, inspection, maintenance and repair. Replacement of an engine took four hours. A replacement sponson cost $24,000. Pan American's major maintenance facilities were located at La Guardia, New York and on Treasure Island in San Francisco Bay, California. ==Operational history==

Entry into service The first aircraft to be delivered was NC18602 which was christened California Clipper. This aircraft was flown on January 27, 1939, by Boeing test pilot Earl Ferguson and Wellwood Bell as co-pilot from Lake Washington to Astoria in Oregon. On March 29, the California Clipper commenced a regular passenger and mail service on the same route. A one-way trip on this route took over six days to complete. Commercial passenger service lasted less than three years, ending when the United States entered World War II in December 1941. Passengers and their baggage were weighed, with each passenger allowed up to free baggage allowance (in the later 314 series) but then charged () for exceeding the limit. The Yankee Clipper flew across the Atlantic on a route from Southampton to Port Washington, New York with intermediate stops at Foynes in Ireland, Botwood in Newfoundland, and Shediac, New Brunswick. The inaugural trip occurred on June 24, 1939. Introduction of the 314A Pan American had an option to purchase further 314s. Confident that the problems that had occurred with the first order had been resolved, and having found the 314 to be more reliable in service than the Martin M-130, they exercised this option, ordering six. The order was placed two days before its expiry date of 1 October 1939. Planned delivery was in 1941, with the goal of doubling the service on both Atlantic and Pacific routes by retiring its remaining two Martin 130s, and allocating six of the 314s to the Pacific and the other six to the Atlantic. This option for a third aircraft was soon exercised. The purchase of the three aircraft included 12 spare GR2600A2A engines at a cost of $16,753 each and $21,750 for 19 Hamilton propellers. The aircraft were to be operated by the British Overseas Airways Corporation (BOAC) and were primarily intended for the UK–West Africa route, as existing flying boats could not travel this route without stopping in Lisbon. The sale made a small net profit for Pan American – priced at cost plus 5% – and provided a vital communications link for Britain, but was politically controversial. In order to arrange the sale, the junior minister Harold Balfour had to agree to the contract with no government approval, leading to stern disapproval from Winston Churchill and lengthy debate by the Cabinet over the propriety of the purchase. Pan American provided training for BOAC staff and delivered the aircraft to La Guardia in New York, where 33 days were spent changing their registration and painting them in a new color scheme. Churchill later flew on the Bristol and Berwick in January 1942 from Washington, D.C. to England, and he praised the plane intensely, At the outbreak of the war in the Pacific in December 1941, the Pacific Clipper was en route to New Zealand from San Francisco. Rather than risk flying back to Honolulu and being shot down by Japanese fighters, it was directed to fly west to New York City. Starting on December 8, 1941, at Auckland, New Zealand, the Pacific Clipper covered over via locations including Surabaya, Karachi, Bahrain, Khartoum and Leopoldville. The Pacific Clipper landed at Pan American's LaGuardia Field seaplane base at 7:12 on the morning of January 6, 1942. The aircraft were then leased back to Pan American for a dollar, with the understanding that all would be operated by the Navy once four-engined replacements for the Army's four Clippers were in service. Only the markings on the aircraft changed. Since the Pan American's civilian personnel had both extensive expertise in using flying boats for extreme long-distance over-water flights and in maintaining them, they continued to be flown and maintained by the company. The Army gave the aircraft the designation C-98, but the Navy—which used a different designation system at the time—disregarded this designation and operated the aircraft under the company designation B-314. Throughout the war the flying boats were employed to transport high-priority passengers (such as high-ranking officers, scientists, war correspondents and USO entertainers), mail and vital military cargo on long distance international routes to the European and Pacific fronts, and to Africa. On outbound flights, the cargo could be as important as vital blood plasma, medical supplies, while on the return they could be vital materials such as beryllium, mica, and raw rubber. The 314 was then the only aircraft in the world that could make the crossing over the South Atlantic. This allowed passengers and military cargo to be carried via Natal, Brazil to Liberia, to connect with the British forces in Egypt and even the Soviets, via the Persian Corridor. In February 1942, forty women were hired by Pan American to replace male mechanics in the hangars at LaGuardia to perform service, repair and overhaul of the Clippers for the European service. Maintenance demands were such that it took "141 mechanics, working three 8-hour shifts, to perform in two days the complete inspection of servicing routine which must be carried out before a Clipper just in from Europe can be sent on the return trip." In January 1943, President Franklin D. Roosevelt traveled most of the way to and from the Casablanca Conference in a Pan-Am crewed Dixie Clipper. While attempting to land at Cabo Ruivo Seaplane Base, in Lisbon, Portugal on February 22, 1943, the Yankee Clipper NC18603 crashed killing 24 passengers and crew. Among that flight's passengers were prominent American author and war correspondent Benjamin Robertson, who was killed, and the American singer and actress Jane Froman, who was seriously injured. From the time of America's entry into World War II in December 1941 through to October 31, 1944, the Pan American 314s flew 9.9 million miles during which they carried 72,621 passengers completing 1,299 flights over the Pacific and 1,595 crossings of the Atlantic. The Clipper had carried 24 passengers and taken 16 hours and 39 minutes, compared with a Lockheed L-049 on that same day transporting 42 passengers, and taking nine hours and nine minutes to cover the same route. The Clippers were then offered to Pan American by the War Assets Administration (WAA) at an asking price of $50,000 each. By this point, the 314s operated by Pan American had each accumulated more than 18,000 flight hours, and together had completed approximately 5,000 ocean crossings and flown more than 12.5 million miles. Of the 12 Boeing 314 Clippers built, three were lost to accidents, although only one of those resulted in fatalities, the loss of Yankee Clipper. After being taken out of service Anzac Clipper, Atlantic Clipper, Capetown Clipper and Pacific Clipper were stored at Floyd Bennett Field in Brooklyn and were advertised for sale by the WAA at the end of January 1946. The four Alameda-stored aircraft were flown south to the milder weather conditions of San Diego which would reduce the deterioration from corrosion. Initially they were anchored in the bay; once their beaching cradles arrived, they were moved out of the water onto the seaplane ramp at the Convair facility at Lindbergh Field in San Diego. Universal Airlines All seven WAA owned aircraft were purchased for $325,000 by Universal Airlines, a non-scheduled carrier and mortgaged to the brokerage firm General Phoenix Corporation of Baltimore. All three were then sold to the aircraft brokerage firm General Phoenix Corporation of Baltimore on April 29, 1948, which stored on their beaching cradles at Harbor Field in Baltimore. By early 1949, World Airways was bankrupt, leaving the Bangor, Berwick and Bristol in Baltimore, while the Atlantic Clipper California Clipper and Dixie Clipper were still in San Diego. During a storm on 7 April 1951 the Bristol broke free from its moorings and sunk in of water, half a mile off Harbor Field. Boland rejected a quote of $20,000 from a salvage company to raise it and attempted to do it himself. He eventually abandoned the aircraft and it was declared to be derelict by harbour officials, who arranged for it to be raised and scrapped. The Bristol had been the last 314 to fly on January 27, 1948. Meanwhile, within a year World Airways had been reorganized under new ownership and was still the registered owner of NC18604Atlantic Clipper, NC18602 California Clipper and NC18605Dixie Clipper, though with General Phoenix Corporation still having a mortgage over the aircraft. They were reports of them still being at Lindbergh Field on San Diego as late as 1951, before they were eventually scrapped. ==Variants==

;Model 314 :Initial production version with GR2600A2 Twin Cyclone engines, six built for Pan American at an average of $668,908 at a time when a DC-3 cost $115,000. In addition, Pan American purchased $756,450 of spares. • The oil capacity was decreased from 206 to 300 gallons due to the use of more efficient hopper oil tanks, which as well as reducing the oil load, improved cold weather engine starting. • A revised interior. • The 314A dispensed with the recessed steps that led up the side of the nose. Each 314A cost Pan American $800,000. Military designations Those pressed into service with the U.S. military were given the following designations: ;B-314 :Five Model 314s who served with the U.S. Navy. ;C-98 :Four Model 314s who served with the U.S. Army Air Forces. ==Operators==

; • Pan American World Airways • United States Army Air Forces • United States Navy • Universal Airlines • American International Airways • World Airways ; • British Overseas Airways Corporation ==Surviving aircraft==

None of the dozen 314s built between 1939 and 1941 survived beyond 1951, with all 12 being cannibalized for parts, scuttled, scrapped, or otherwise written off. Underwater Admiralty Sciences, a non-profit oceanographic exploration and science research organization based in Kirkland, Washington, announced in 2005, at the 70th Anniversary of the first China Clipper flight in San Francisco, its plans to survey, photograph, and possibly recover the remains of the hulls of two sunken 314s: NC18601 (Honolulu Clipper), scuttled in the Pacific Ocean in 1945; and NC18612 (Bermuda Sky Queen, formerly Cape Town Clipper), sunk in the Atlantic by the Coast Guard in 1947. UAS has also spent significant time at Pan American reunions and with individual crewmembers and employees of Pan American conducting videotaped interviews for the mission's companion documentary. However, as of 2014, no search or recovery had been attempted, with the most recent news from 2011 suggesting that the company was still in need of at least US$8 million to get the plan under way. There is a life-size 314 mockup at the Foynes Flying Boat Museum, Foynes, County Limerick, Ireland, located on the site of the original transatlantic flying-boat terminus. ==Specifications (314A Clipper)==

Inspired by the airplane, Smith Corona designed, manufactured, and marketed a typewriter model it called the Clipper from 1945 to 1960. The logo prominently featured the Boeing 314 Clipper on the typewriter's body which served as a reminder of the luxury and design of the original airplane. It was the origin of one of the nicknames of Joe DiMaggio, the "Yankee Clipper". The novel Night Over Water (1991) by Ken Follett relates a fictitious last commercial flight of the Clipper at the beginning of World War II. The novel includes detailed descriptions of both the passenger and the flight decks, as well as of the operation of the plane. ==Notable aircraft==

• NC-18601 – Honolulu Clipper • NC-18602 – Pacific Clipper/California Clipper • NC-18603 – Yankee Clipper • NC-18605 – Dixie Clipper ==See also==