History

Pan American World Airways originally requested the DC-7 in 1945, as a civilian version of the C-74 Globemaster military transport. It canceled its order shortly afterward.

American Airlines revived the designation when it requested an extended-range DC-6 for its transcontinental services. At the time, the Lockheed Constellation was the only aircraft capable of making a non-stop coast-to-coast flight in both directions. However, Douglas was reluctant to build the aircraft until American Airlines president C. R. Smith placed a firm order for twenty-five at a price of $40 million, thus covering Douglas's development costs.

The prototype flew in May 1953 and American received its first DC-7 in November, inaugurating the first non-stop coast-to-coast service in the country (taking 8 hours) and forcing rival Trans World Airways to offer a similar service with its Super Constellations. Both aircraft, however, frequently experienced in-flight engine failures, causing many flights to be diverted.

The original DC-7 was followed by another variant, the DC-7B, which was identical except for increased fuel capacity in extended engine nacelles, which resulted in greater flight range. South African Airways used this variant on their Johannesburg to London route.

The early DC-7s were only sold to U.S. carriers. European carriers could not take advantage of the small range increase in the early DC-7, so Douglas released an extended-range variant, the DC-7C (Seven Seas) in 1956. A 10 feet (3.0 m) wing-root insert added fuel capacity, reduced induced drag, and made the cabin quieter by moving the engines further outboard. The fuselage, which had been extended over the DC-6B's by a 40 inches (100 cm) plug behind the wing for the DC-7 and -7B, was lengthened by a similar plug ahead of the wing to give the DC-7C a total length of 112 feet 3 inches (34.2 m).

Pan Am used DC-7C aircraft to inaugurate the first non-stop London to New York service against the strong westerly headwinds. The DC-6B and Super Constellation had been able to fly non-stop eastbound since 1952. British Overseas Airways Corporation were forced to respond by purchasing DC-7Cs rather than wait on the delivery of the Bristol Britannia. The DC-7C found its way into several other overseas airlines' fleets, including SAS, which used them for cross-polar service to North America and Asia. However, DC-7C sales were cut short by the arrival of Boeing 707 and Douglas DC-8 jet aircraft a few years later.

Starting in 1959, Douglas began converting DC-7 and DC-7C aircraft into DC-7F freighters, which extended the life of the aircraft past its viability as a passenger transport.

Operators

Airlines

Historical operators of the DC-7 include Aeromexico, Alitalia, American Airlines, BOAC, Braniff Airways, Caledonian Airways, Delta Air Lines, Eastern Air Lines,Japan Airlines, KLM, National Airlines, Northwest Orient, Panair do Brasil, Pan American World Airways, Sabena, SAS, South African Airways, Swissair, THY, TAI, and United Airlines.

In 2007, 73 DC-7s remained on the U.S. civil aviation registry, used mainly for cargo and as airtankers. Due to its engine problems, the DC-7 has not had the same longevity as the DC-6, which is still used by a number of commercial operators.

Military Operators

Orders and production

Specifications (DC-7)

General characteristics

• Crew: 3 or 4
• Capacity: 99 to 105 passengers
• Length: 112 ft 3 in (37 m)
• Wingspan: 127 ft 6 in (42 m)
• Height: 31 ft 10 in (10.5 m)
• Wing area: 1,637 ft² (152 m²)
• Empty weight: 72,763 lb (33,005 kg)
• Max takeoff weight: 143,000 lb (65,000 kg)
• Powerplant: 4× Wright R-3350-18EA1 Turbo-Compound radial piston engines, 3,400 hp (2,535 kW) each

Performance

• Maximum speed: 406 mph (653 km/h)
• Cruise speed: 355 mph (570 km/h)
• Range: 4,605 mi (7A) / 5,635 mi (7C) (7,410 km (7A) / 9,070 km (7C))
• Service ceiling: 25,000 ft (7,600 m)
• Rate of climb: 1,043 ft/min (318 m/min)
• Wing loading: 87.4 lb/ft² (427.6 kg/m²)
• Power/mass: 0.10 hp/lb (160 W/kg)