Friday, April 18, 2008

Not Classic Jetliners (4) : Hawker Siddeley Trident

A competitor to the much more successful Boeing 727, the Hawker Siddeley Trident was designed during the 1950s as a short & medium range jet airliner able to carry about 110 passengers. The design, at the time a de Havilland project (the DH 121), was the first airliner with 3 jet engines and the first tri-jet design with the engines all at the rear of the plane, this configuration was was also taken up by the 727 and Russian Tu-154.

The Trident 1, designed to a BEA (British European Airlines) requirement, first flew in early 1962. BEA had insisted on a smaller aircraft than originally envisaged (it could carry 98 passengers) unfortunately other potential customers like American Airlines wanted a bigger aircraft. American Airlines bought the 727 instead which ironically was much closer to the original DH 121 design than the Trident 1. The Trident entered service with BEA in 1964 and was the first civil aircraft fitted with a flight recorder and be equipped for automatic blind landings for use in adverse weather conditions such as fog. In 1966 the Trident was the first airliner to land in fog.

Throughout the 1960s there were continuous improvements to the design including the Trident 1E which was close to the original DH 121 size carrying 140 passengers and the 2E which had further capacity and extra range. The latter achieved a notable sale when 33 were ordered the Chinese national airline CAAC and Chinese air force. One Chinese Trident was lost in mysterious circumstances over Mongolia when Lin Biao was using it to try and defect to the USSR. The official story is that the Trident ran out of fuel. A Trident has also been left marooned at Nicosia International Airport which has been abandoned since 1974 due to the Turkish invasion of northern Cyprus.

The final version, the Trident 3 had a 5m fuselage plug and was able to carry up to 180 passengers. The Trident 3 was actually a 4 engined aircraft as it had a small RB162 turbojet which could be used for take-offs, the Tridents had a reputation for needing plenty of runway to get airborne so the extra boost was especially welcome in the larger Trident 3! The reason for the problems with take-off was that the wing was optimised for high speed (the Trident was one of the fastest subsonic jet airliners) and not lift at low speeds.

Trident development ceased in the early 1970s and small sales continued but total production of the Trident was just 117 when the last example was delivered in 1978. Although technically advanced the Trident was an expensive airliner to operate and had a rival with Boeing's marketing muscle and name behind it. The rival 727 had sales of 1832.

No Tridents are thought to be active today, British Airways who inherited the BEA fleet withdrew them in the 1980s though they remained in service in China until the 1990s. A number of Tridents have been preserved or are in use in various locations for fire training.

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