After a relatively short passenger operation, the DC-7 became the main candidate for conversion into a cargo plane to replace similarly converted DC-BAs. In 1959, Douglas launched a conversion line. Work on bringing to the standard DC-7F cost $ 350,000 and lasted three months. Two pairs of cargo doors were put on the plane, the floor was strengthened, and, at the customer’s choice, a system for cargo handling was installed. The cabin windows were often closed with metal caps, although sometimes they were left if it was expected that later the aircraft would be converted again into a passenger one. Aircraft are convertible cargo and passenger, but most often they were used as transport for the transport of commercial cargo weighing up to 15,700 kilograms.
Among the first orders completed were a DC-7 for United, 10 DC-7B for American, one DC-7B for Rapud, and two DC-7C for KLM, BOAC, Alitalia, and Japan Air Lines ” “United” aircraft brought to the standard DC-7B. Later, Americans bought four more freight DC-7Bs, while KLM bought 2 DC-7Cs. For many airlines, Douglas also carried out floor reinforcement and door installation, and they performed the rest of the work on their own while maintaining the ability, if necessary, to quickly turn the aircraft back into a passenger one. Refurbishment work was also carried out by Lockheed Aircraft Services (LAS), which in 1960 supplied 10 Pan-7C (F) to Pan Am and several other aircraft to other carriers.
The DC-7s were eventually replaced by DC-8Fs and Boeing 707Cs, many of which then appeared on the secondary aircraft market, where they were quickly sold out at fairly high prices.
Some aircraft are used for fire fighting. For these purposes, a container is installed in the cargo compartment allowing to take up to 15 tons of water on board. In total, several dozen DC-7Bs and several DC-7Cs were converted.
- Modification: DC-7F
- Wingspan, m: 35.81
- The length of the aircraft, m: 33.24
- The height of the aircraft, m: 8.71
- Wing Area, m2: 136.00
- Weight kg: empty plane 30030; take-off maximum 57153
- Engine Type: 4 PD Wright R-3350-988TC18EA4 Turbo-Compound
- Horsepower: 4 x 3400
- Maximum speed, km / h: 645
- Cruising speed, km / h: 555
- Ferry range, km: 7130
- Practical range, km: 5860
- Practical ceiling, m: 8656
- Crew: 3 + 4
- Payload: standard – 99 passengers, maximum – 105.