Beginning in 1943, the company Lockheed planned stretched variants of the Constellation family. The first was the
L-049 with a fuselage lengthened by and the second the
L-749 stretched .
Douglas launched a stretched version of its
DC-6 airliner as a cargo transport, designated DC-6A, for both military and civilian operators. Douglas was soon to launch a passenger version (the DC-6B) of this new aircraft. The DC-6B could carry 23 more passengers than Lockheed's current production L-749 Constellation. Turbo-compound engine used on later models of the L-1049 In 1950, Lockheed had repurchased the
XC-69 Constellation prototype from the
Hughes Tool Company. The XC-69 was equipped with four
Pratt & Whitney R-2800 radial engines instead of the
Wright R-3350s used on production models. Lockheed had installed R-2800s on the prototype to test them as an option for the L-049. Lockheed stretched XC-69 by , to become the basis for the L-1049 Super Constellation. The aircraft first flew in 1950, still fitted with R-2800 engines. It was then fitted with R-3350 956-C18CA-1 engines with jet stacks for slightly increased thrust. Later modifications included strengthened landing gear and larger vertical stabilizers.
Eastern Air Lines ordered 10 aircraft, while
Trans World Airlines (TWA) followed with an order for 14. The L-1049 had some 550 improvements and modifications compared to the L-749, including greater fuel capacity, rectangular windows, larger cockpit windshields, and improved heating and pressurization. L-1049C at
London Heathrow Airport, 1955 In 1953, R-3350 Turbo-compounds were made available for civil use. Lockheed incorporated them into the L-1049C, which first flew on February 17 of that year. The R-3350-972-TC18DA-1
turbo-compound engines on the L-1049C had a new
turbine system, the Power Recovery Turbines (PRT). Each engine's exhaust gas flowed through three turbines, increasing power by . One drawback of the PRT was the visible flame from the exhaust pipes; this was resolved by placing
armor plating thick under the stack. The L-1049C had a higher cruising speed and climb rate. Although lacking the range of the DC-6B, the L-1049C had identical performance to the Douglas and could carry a larger payload. The wings of the new model were strengthened, cabin soundproofing was increased, and the landing gear retraction system was improved. A new series of interior layouts was offered for the new model: "Siesta" (47 passengers with increased luxury), "Intercontinental" (54 - 60 passengers), and "Inter-urban" (105 passengers). Each of these new layouts included
reading lights at each seat. Forty-eight L-1049Cs were built, being used by Eastern, TWA,
Air France,
KLM,
Trans-Canada Air Lines,
Qantas,
Air India,
Pakistan International Airlines,
Avianca,
Iberia,
Línea Aeropostal Venezolana and
Cubana de Aviación. L-1049G at
Los Angeles International Airport, 1964 A freighter version, the L-1049D, first flew in August 1954. It had two cargo doors on the left side and a reinforced magnesium floor as used on the R7V-1 military variant of the L-1049B. The L-1049D could carry a payload and had a volume of . At the time of its first flight, the L-1049D was the largest civil cargo aircraft. In the end, four were produced, all delivered to
Seaboard & Western Airlines. Two of the four L-1049D aircraft were later converted to L-1049H standards. The L-1049E was more successful; 28 were delivered to eight airlines. Similar to the L-1049C, the L-1049E was able to carry the same load as the L-1049D. The L-1049C and L-1049E could not usually fly from Europe to New York nonstop against the wind. Lockheed thought of fitting a new variant based on the L-1049E with more powerful engines, but the project was cancelled. A different variant surfaced: using the L-1049C as a base, R-3350-972-TC18DA-3 turbo-compound engines were fitted. The aircraft could carry 71 to 95 passengers at a speed of .
Wingtip tanks of total capacity were incorporated, increasing range by . A new
Bendix or
RCA weather radar could be installed in the nose, which would change the nosecone shape. New
Hamilton Standard or
Curtiss Electric propellers were offered. This new version of the L-1049 with over 100 modifications from the L-1049C was unveiled as the L-1049G (the L-1049F being already used for the military C-121C). Over 100 L-1049G aircraft were ordered by sixteen airlines. The L-1049G flew on December 17, 1954, and entered service with TWA and Northwest in 1955. The nickname "Super G" (first used by TWA) was later adopted for the L-1049G. L-1049G The L-1049H flew on November 20, 1956. Called "Super H" and "Husky", the L-1049H was a convertible passenger/freight aircraft, mating a C-121C-based fuselage with L-1049G components. The cargo hold had a volume of when including the lower hold. The aircraft could carry up to 120 people with seats, luggage lockers, and toilets, all available, along with the option of decorating the walls of the aircraft. When not in use, the luggage lockers and seats could be stowed in the lower hold. The aircraft entered service with Qantas a month later. Some L-1049G and H aircraft in later production were fitted with the TC-18EA series engines used on the
L-1649 Starliner. A final variant was planned in 1957, known as the L-1049J. Powered by four R-3350-988-TC-18EA-6 engines, the L-1049J was based on the L-1049H with the wings of the
R7V-2 Constellation and an extra fuselage-mounted fuel tank. ==Operational history==