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The Douglas C-74 Globemaster was a United States heavy-lift cargo aircraft built by the Douglas Aircraft Company in Long Beach, California. The aircraft was developed after the Japanese attack on Pearl Harbor. The long distances across the Atlantic and, especially, Pacific oceans to combat areas indicated a need for a transoceanic heavy-lift military transport aircraft. Douglas Aircraft Company responded in 1942 with a giant four-engined design. Development and production modifications issues with the aircraft caused the first flight to be delayed until 5 September 1945, and production was limited to 14 aircraft when the production contract was canceled following V-J Day.〔Williams 1995, p. 43.〕 Although not produced in large numbers, the C-74 did fill the need for a long-range strategic airlifter, in which the subsequent Douglas C-124 Globemaster II was used by the Air Force for many years. ==Design and development== The Douglas Aircraft Company began studies at their Santa Monica division in early 1942 for a transport capable of fulfilling the global logistical needs of the U.S. military. Its "C-74 Project Group" used their company's DC-4 as a basis and concentrated on enlarging its capabilities. The group's design philosophy was to build a "no-frills" aircraft able to accommodate much of the Army's large equipment including light tanks, two howitzers with their towing vehicles, two angle bulldozers, and smaller utility vehicles. This became the Douglas Model 415 and a cost-plus contract worth more than $50 million was signed 25 June 1942 for 50 aircraft and one static test article. There were no XC- or YC-74 models produced.〔Williams 1995, pp. 40–41〕 This first flight of a C-74 occurred on 5 September 1945. The first C-74, ''42-65402'', was airborne just two months after it rolled off the assembly line. At the time of its first flight, the C-74 was the largest landplane to enter production, with a maximum weight of 172,000 lb (78,000 kg). It was able to carry 125 soldiers or 48,150 lb (21,840 kg) of cargo over a range of 3,400 mi (5,500 km). Perhaps the most notable feature of the C-74 was its cockpit arrangement with separate canopies over the pilot and copilot; the same arrangement was used for the XB-42 Mixmaster. This arrangement was unpopular with flight crews, however, and the aircraft were retrofitted with a more conventional arrangement. During the life of the aircraft, the radial engines were also upgraded to 3,250 hp (2,424 kW) Pratt & Whitney R-4360-49 engines. The aircraft was 31 feet longer than the C-54 Skymaster, and would be 24 feet longer than the proposed C-118 Liftmaster.〔Tambini〕 The second built, ''42-65403'', c/n 13914, crashed during flight testing on 5 August 1946 at Torrance, California when it lost a wing during an overload dive test. All four crew bailed out successfully.〔("ASN Aircraft accident Douglas C-74 Globemaster I 42-65403, Torrance, California." ) ''Aviation-safety.net.'' Retrieved: 8 May 2010.〕 The fourth aircraft was diverted to a static test article at Wright Field, Ohio and virtually every component was tested to destruction between August 1946 and November 1948. This was done in order to determine the individual components' ability to withstand design loads. The fifth C-74 built was modified to be a prototype for the C-124 Globemaster II, which used the same wing as the C-74, but used a much larger fuselage. This newer aircraft quickly superseded the C-74 in service.〔 Douglas had every intention to adapt the aircraft into a civil airliner once the war ended. Pan American World Airways began negotiations in 1944. Their civilian model would be dubbed a DC-7 by Douglas (Model 415A) and the 'Clipper Type 9' by Pan American. Pan American intended to use the 108-passenger aircraft for international travel between New York, Rio de Janeiro, and other cities. The major difference between the military cargo aircraft and the civil airliner was the non-pressurized fuselage of the military C-74 and the pressurized DC-7. The passenger compartment was to be outfitted with a lounge bar, dining area and sleeping cabins for night flights. In June 1945, an order was placed for 26 DC-7 aircraft.〔 With the need for military aircraft greatly reduced by the end of World War II, the order for 50 military aircraft was canceled in January 1946 after production of only 14 aircraft. This cancellation also ended plans to build an airliner version of the C-74 for the civilian market, as the limited military production run increased the cost per civilian aircraft to over $1,412,000 and Pan American canceled its order. Douglas then canceled the DC-7 designation. The DC-7 designation was later used for a completely different civilian airliner project in the early 1950s, having no relationship to the C-74.〔〔("USAF Globemaster Serial Number Search." ) ''cgibin.rcn.com.'' Retrieved: 26 November 2010.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Douglas C-74 Globemaster」の詳細全文を読む スポンサード リンク
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