For questions on the A300-based Beluga and A330-based Beluga XL, two outsize cargo aircraft primarily used by Airbus to transport pieces of Airbus aircraft.
The Airbus Beluga (officially the Airbus A300-600ST Beluga) is an outsize cargo aircraft derived from the airbus-a300; the newer Beluga XL (Airbus A330-743L), an even larger aircraft, is similarly derived from the airbus-a330. There are five Belugas (soon to be joined by the first two Beluga XLs), which are primarily used by airbus to transport portions of their aircraft (such as wings and fuselage segments) to their final assembly locations, but also see service transporting various other extremely large items of cargo (such as heavy machinery, space station components, and large artworks) around the world.
Airbus originally transported all its aircraft parts by truck, train, and boat (the segments of the airbus-a380, which are too large to fit in the Belugas, are still transported in this way); in 1972, it acquired four Super Guppy aircraft (highly-modified derivatives of the boeing-377-stratocruiser) formerly owned by NASA, but these, too, proved increasingly unsatisfactory over the years as Airbus production grew.
In the early 1990s, Airbus initiated a program to replace the Super Guppies with a highly-modified version of their A300; the resulting aircraft, which first flew in September 1994 after two years of construction and began carrying cargo for Airbus in October of the next year, was initially known as the A300-600 Super Transporter (A300-600ST for short), but quickly acquired the nickname Beluga for its resemblance to the whale of the same name. The Beluga nickname was eventually adopted as part of the aircraft's official designation. Four more Belugas were built, the last being completed in 1999.
Despite its great size, the Beluga is itself becoming too small for Airbus's needs, and is planned to be augmented - and, later on (in the 2021-2025 timeframe), replaced - by the Beluga XL, modified from the airbus-a330 in the same way as the original Beluga was modified from the A300. The Beluga XL, which first flew on 19 July 2018, is larger and has a longer range; it is designed to be able to move two airbus-a350 wings at once, where the original Beluga can only move one. The Beluga XL received a type certificate on 13 November 2019, and the first two (of a planned six) entered service in early 2020, with the first operational flight on 9 January. Due to very high aircraft production rates creating a pressing need for every available outsize-cargo aircraft, the five original Belugas are all planned to remain in service until the first three Beluga XLs are all operational (raising Airbus's fleet temporarily to a total of eight Belugas of all kinds), before being gradually sold off by 2025 as the later XLs come on line.
For both Belugas, the most obvious modification is the massive, bulbous cargo compartment grafted onto the upper frame of the A300 or A330 fuselage. This cargo compartment is loaded and unloaded through a large swing-up door at the front of the compartment; to make room for this door, the aircraft's nose and cockpit area are shifted downwards, giving the Belugas' lower fuselages a slightly snake-like appearance. The Belugas' vertical-stabilizers are considerably larger than those of the airliners on which they are based (the original Beluga's vertical stabilizer is a modified version of that used on the airbus-a340, rather than that from a stock A300, while that of the Beluga XL is an enlarged version of the stock A330's vertical stabilizer), and their horizontal-stabilizers feature additional, auxiliary vertical stabilizers (mounted on the outboard ends of the paired horizontal stabilizers) to compensate for the decreased effectiveness of the primary vertical stabilizer caused by its being in the wake of the massive cargo compartment. Finally, the engines of both aircraft were uprated slightly from the stock models (although not by very much, as aircraft parts, while quite bulky, are actually fairly light compared to most types of air cargo, due to the large amounts of empty space they contain).
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