<p>During World War II the Douglas Aircraft Co. planned three new commercial transports. The DC-6 was to be a conventional stretched DC-4. The DC-7 was to be basically similar but much larger, to fly the North Atlantic. The DC-8 was to be a 38-seater with the extraordinary behind-the-tail propellers of the XB-42 bomber. This DC-8 remained on the drawing board (the designation being used 10 years later for a big jetliner). The DC-7, however, did get built.
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<p>Originally, it was planned as the flagship of Pan American's fleet, carrying 108 passengers by day and 76 by night, in a vast tube-like pressurized fuselage. The engines were to be four 3,500-hp (2,834-kW) Pratt & Whitney R-4360 Wasp Majors, by far the most powerful engines available. The design bristled with advanced features, such as completely integral tankage along the wings, full-span Fowler flaps (the outer sections acting as ailerons) and separate cockpits for the two pilots, with side-by-side fighter-type canopies. Of course, tricycle landing gear was adopted, each unit having twin wheels.
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<p>The DC-7 went into full engineering development in 1942, and Douglas immediately received an order from the Army Air Force for 50, with the designation C-74. PanAm had already named the DC-7 the Globemaster, and the airline ordered 26, with the intention of using them to open a nonstop Atlantic service. At first all the effort had gone into the DC-7, with a pressurized fuselage sumptuously furnished with separate cabins, dining area, lounge bar and cabin crew quarters. The windows were to be long ovals, as in the DC-6 but larger, divided by a central vertical tie into front and rear sections. With a span of 173 ft 3 in (52.8 m) and maximum take-off weight of 145,000 lb (65,772 kg), the DC-7 was appreciably bigger than the future Boeing 377 Stratocruiser, which was to have the same engines.
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<p>War priorities caused Douglas to switch the engines to the C-74. This retained the Douglas engineering number of 415A but differed in several respects. The fuselage was unpressurized, partly because the Army naturally wanted its biggest aircraft to carry heavy cargo. This could be loaded by either of two electrically powered hoists immediately aft of the wing. Each was rated at 8,000 lb (3,629 kg), and both hoists could be used together to lift a load of 16,000 lb (7,257 kg). Once above floor height the hoists could be traversed forwards along the entire 75-ft (22.8-m) length of the cabin. Interior width was 11 ft 6 in (3.5 m), and the entire floor was stressed to bear a load of 200 Ib/sq in, with cargo tiedown shackles on a 20-in (0.95-m) grid.
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<p>Certainly the Globemaster promised to live up to its name. It could take on board 10 of the biggest aircraft engines, or 15 V-1710 fighter engines, or two T9E1 light tanks, or almost any combination of artillery, ammunition, trucks, radars or other heavy or bulky loads. Alternatively, the interior could be arranged for 125 troops or 115 stretcher casualties. With maximum payload of 55,586 lb (2,521 kg) the range was around 3,000 miles (4,827 km). During 1944 the aircraft was upgraded to have the new Sperry A-12 autopilot, and a catwalk was provided along each wing for rear access to the engines in flight. Hamilton Standard four-bladed reverse-pitch propellers were fitted.
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<p>As they were all ordered together, the 50 Globemasters were numbered as one batch, 42-65402/65451, but the first was styled as the XC-74. The whole program was handled by the wartime Long Beach factory, which replaced Santa Monica as company headquarters. The monster was rolled out in August 1945, very soon after the end of the war, and made an uneventful first flight on 5 September. Clearly the giant would perform as advertised, but with the war's end the Army cancelled the last 36 aircraft, leaving just 14. Much more seriously, PanAm was having second thoughts. Although the DC-7 had been planned to cruise at 296 mph (476 km/h), actual experience showed that a good cruising speed for long ranges might be nearer 176 kt/325 km/h) (this was, in fact, the published speed for cruising the C-74). After much agonizing, PanAm cancelled the contract in late 1945, giving as reason the high initial cost. Shortly afterwards the airline invested in a fleet of Boeing Stratocruisers.
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<p>This left Douglas likely to incur a large loss on the program. The 14 aircraft were completed, all being delivered to Air Transport Command between 11 October 1945 (which shows how few problems there were) and 28 April 1947. This was perfect timing for the Globemasters to be nicely settled down in service when the Berlin Airlift started in July 1948. The C-74s were by far the biggest and most capable aircraft involved in that operation. Subsequently, the unusual cockpits, with what were popularly called 'bug-eye canopies', were redesigned to form a normal flight deck with a single glazed area on top. They proved successful in service and were not withdrawn until after 1959. Remarkably, in view of their size and operating costs, three were demilitarized: 65403 became N3182G and then HP-385 serving with Aeronaves de Panama, 65408 became N8199H and then HP-367, and 65409 became N3181G and finally HP-379. One was still flying as far as Bogota and Miami in the mid-1970s.
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<hi style=hdr1>Specification</hi>
<hi style=hdr2>Douglas—C-74 Globemaster I</hi>
<list style=aflst>
<item><hi format=bold>Type:</hi> strategic long-range transport
<item><hi format=bold>Powerplant:</hi> four Pratt & Whitney R-4360-49 radial piston engines rated at 3,500 hp each
