Development of what became afterwards known as “Constellation” started with Lockheed in Burbank California in 1938. The “Excalibur”, as the plane at first was named, was the first 4 engined plane developed by Lockheed. The design started with a modest number of 28 passengers and Pratt & Whitney engines of 600 HP each. The first design also didn’t have a pressurized cabin.
After discussions with possible customers, TWA being the most important one, the design was stretched to be able to compete with the Douglas DC-4E and the Boeing Stratoliner, both of which were in a comparable stage of development.
When the USA got involved in WW II in 1941, the discussion between TWA and Lockheed already was at a number of 64 passengers and Wright Duplex Cyclone engines of 2200 HP each, together with a pressurized cabin.. During the war development was continued as an military transport aircraft with the name C-69. The USAF ordered 260 of them in 1942, but only 15 C-69’s were delivered in 1945. After the war, the name was changed from L-49 Excalibur into L-049 Constellation. The maiden flight of the first commercial Constellation took place in August 1945.
Because the KLM had shown interest in the Lockheed design in 1939, and even seems to have placed an order already then for 4 aircraft, it doesn’t surprise that the first European Constellation was the PH-TAV “Venlo” that could already start its services for KLM on the 4th of September 1946.
The Constellations then gradually took over the long distance routes from the DC-4 Skymasters.
The first KLM Constellations were of the L-049 type, with 2200 HP Wright 739C18-BA3 engines. Later planes were of the L-749 type, with a reinforced landing gear and more fuel capacity. The range was extended to 6100 km and maximum take-off weight was enlarged up to 46 tons.
In 1948, Lockheed offered an even stronger variant, the L-749A, allowing a maximum take-off weight of 49 tons. Eventually, KLM modified its existing 749’s into 749A’s and exchanged its 6 049’s for 749A’s, bringing the total to 21 Constellations.
The CKLM Constellations first flew officially for the NGAT, in fact the Dutch government. This was changed into KLM in 1948, when India and Pakistan closed their airspaces for – what was seen as – Dutch military planes.
Some key figures of the L-749A:
Wing Span: 37.52 m; Length: 29.05 m; Wing area: 151.80 m2; take-off power: 2,500 HP; engine: 749C18-BD1; cruise speed: 504 km/h at 6,100 m altitude; operational ceiling: 7,351 m; max. range: 7.800 km with max. fuel.