Hawker Siddeley Trident
The Hawker Siddeley HS -121 Trident was a designed for short and medium-haul jet powered airliner. It was originally developed from the de Havilland Aircraft Company in the 1950s, under the model designation DH121. After de Havilland in 1959 was merged with Hawker Siddeley Group, the DH121 was further developed as HS -121 and finally built.
The Trident went back to a tender of the British European Airways ( BEA), which she was only moderately attractive to other airlines. Within Europe, however, it played an important role, even if they eventually had their high operating costs has been relatively short in use. British European Airways went together in 1972 BOAC in today's British Airways, which replaced their Tridents in the 1980s by the Boeing 737 and Boeing 757.
History
In July 1956, BEA requested offers for a new medium-range aircraft to replace their Vickers Viscounts on longer European routes by jet-powered aircraft can. The newly developed type should next to a smaller short-distance pattern (which won the tender for this BAC 1-11 ) can be used. Several designs were submitted for the medium-range type, including the Bristol 200, the Avro 740, the Vickers VC11 - and the de Havilland DH 121, which was officially in 1958 determined the winner of the BEA - tender.
The DH 121 was the first " Tri - Jet", that is the first design ever with three engines. The developers chose this configuration because it represented their opinion, the best compromise between economic cruising and safe start in the event of an engine failure. The aircraft initially looked, not surprisingly, like a reduced de Havilland Comet with three engines. Also the rear with height and fin resembled the first of the Comet, in contrast to the later T-tail of the HS -121 Trident. The engines were already, as with the Sud Aviation Caravelle at the rear, so that the wings had to wear no engines and could be designed to guarantee high speed down. Target was about 965 km / h (600 mph). The DH 121 should offer two-class configuration of 111 passengers, have an average range of 3330 km and a flying weight of 63,000 kg, and thrust are powered by three Rolls- Royce Medway engines with 13,790 lbf each ( 61.34 kN).
At this point, it was decided at BEA that a 111- seater was too large for the existing routes, whereupon BEA carefully tried just "their" aircraft tailor to their needs. The Trident design was a result, smaller, which led, among other things, that only much smaller Rolls- Royce Spey 505 engines à 9,850 lbf ( 43.8 kN) were provided thrust at a flying weight of 48,000 kg and an average coverage of 1500 km and accommodates up to 97 passengers. This design decreed the first on the T-tail, which should thenceforth have all other versions. In addition, the bug has been redesigned, making this version also externally significantly different from the comet -like origin of design. The aircraft was now - called Trident 1 - after a contest for naming. BEA was much happier with this smaller design than before and ordered on August 12, 1959, first 24 copies.
Hawker Siddeley Aviation, founded in 1959 as a merger of several British aircraft manufacturers, began now to hold also for other customers out; 1960 began talks with American Airlines, but called for a greater range - which is not without a certain irony, since the original DH 121 the conditions of American fulfilled almost perfect. Nevertheless, it began with the development of a new Trident 1A, which offered a higher -up weight of 54,000 kg and an increased average range of 2,900 km and from stronger Spey 510 engines with 10,700 lbf ( 47.6 kN) thrust was driven. American Airlines ultimately opted against the Trident 1A and for the Boeing 727, which corresponded almost exactly to the specifications of the original DH 121.
Some of the changes to the Trident 1A opposite the Trident 1 were still implemented in the first prototype, which was eventually known as Trident 1C. The main difference was a larger fuel tank in the center section of the wing, making the aircraft weight was 52,000 kg and the average range increased to 2250 km. The first Trident 1, with the registration G - ARPA, made its maiden flight on January 9, 1962, was provided by BEA in service on 1 April 1964. 1965, BEA operates a fleet of 15 Tridents until March 1966 there were 21
Hawker Siddeley proposed at this time an improved Trident 1C under the name Trident 1E ago. You should have a flying weight of 58,000 kg Spey 511 engines with 11,400 lbf ( 50.7 kN ) of thrust and a larger wing area ( with larger aspect ratio ). The hull remained unchanged, provided however - six seats per row - 140 passengers. These changes brought the 1E back closer to the original concept of the DH 121, but with a total of 7,000 lbf (31 kN ) less propulsive thrust. Built for high speeds wing produced at lower speeds less lift, which led, together with the weak shear means that the Trident 1E very long needed to take off. This brought her in the press nicknamed the " Ground Gripper " (such as " floor stapler " ) a. The new version has sold only difficult - Kuwait Airways and Iraqi Airways ordered three each, four PIA (which were later sold to CAAC ), Channel Airways and Northeast Airlines, two and Air Ceylon a copy.
At this point there was BEA that the Trident is now no longer sufficient reach for the ever- expanding route network offered, so a version was needed with further extended range. Hawker Siddeley designed then a further development, the Trident 1F. She got the Spey 511 engines of 1E and an elongated by 2.8 m Hull. Your flight weight was 60,000 kg and in the original seating configuration with five seats per row, it offered 128 passengers. BEA wanted 10 Trident 1F order and take options on a further 14. During the development of the 1F showed that so many changes have been made that Hawker Siddeley decided finally to call the Trident 2E, where E is " Extended Range " ( increased range ) stood. The 2E was finally equipped with Spey 512 engines with a thrust of 11,930 lbf each ( 53.1 kN) and had a flying weight of 65,000 kg, and an average range of 3,200 km. In addition, the wing leading edges were fitted with slats and the span increased by ajar to the research of Erich von Holst and Dietrich kitchen man wingtips. BEA bought 15 copies, Cyprus Airways 2 and the Chinese national airline CAAC 33 First flight of the Trident 2E took place on 27 July 1967, BEA took the line service with this pattern on in April 1968.
Meanwhile, the Trident formed the backbone of the BEA fleet - now that it was widespread in use, BEA demanded an even larger pattern. Hawker Siddeley offered two possible types of 1965: first, the HS -132, a larger, only twin-engine, aircraft with seating for 158 passengers, which still strongly resembled otherwise the Trident; on the other, mounted HS- 134 with engines under the wings and space for 185 passengers. The HS -134 was a very advanced design, the good 15 years later put on the market Boeing 757 was similar. Both HS- 132 and HS -134 should be driven with the located at that time in the development of Rolls- Royce RB -178, a jet engine, which as one of the first should have a high bypass ratio. BEA chose instead, Boeing 727 and 737 to buy to replace both the BAC 1-11 and the Trident. Against this plan, the British government said ( the BEA was one ) but later a veto from.
BEA then turned back to Hawker Siddeley and opted instead for a stretched version of Trident, the Trident Trident 3 had a stretched 3 to 5 m Hull with room for up to 180 passengers, an increased flying weight of 65,000 kg and a modified wing to increase the aspect ratio. The engines should remain unchanged; BEA rejected the pattern from then, since one due to the takeoff and climb problems of Trident 2E feared that the Trident 3 would no longer have been in hot and high-altitude environment capable of ever leaving the ground. Since the Spey 512 was the last model of the Spey series, it was difficult to give the aircraft additional thrust. Instead of a new type of engine installed - which would have been difficult since one at least was in the vertical tail, which would have adjusted accordingly must be aerodynamically - Hawker Siddeley decided to incorporate a fourth engine in the rear. It was the tiny Rolls -Royce RB.162 -86 turbojet engine, which had its own air supply by two movable flaps on the rear bumper. The engine was used only when necessary and gave the Trident 15 % more thrust for takeoff at increased only by 5% by weight. BEA accepted this somewhat odd mixture under the name Trident 3B and ordered 26 copies. The first flight took place on December 11, 1969 held its first scheduled flight on 1 April 1971. A further increased fuel capacity led to the Super Trident 3B, which has sold two of CAAC.
An important technological feature of the Trident was her was based completely automatic blind landing system to the autopilot SEP5 of Smith Industries. With it, the plane was able to land in weather conditions where other types would have been diverted to other airports, which improved the punctuality rate of Trident. However, this purpose had to make room for the electronics, puts the nose wheel to the left, the machine gave a special appearance. The system was tested in 1964 and approved in 1968 for the line use the CAT II. Until the end of 1970 already 7500 landings were carried out with this system by BAE. In 1972, the approval for CAT IIIA CAT IIIB and 1975 extended to.
1977 fatigue cracks were found in the wings of the Trident 3 British Airways. All specimens were transported back to the manufacturer where repairs were carried out, after which all three Trident were put back into service. British Airways introduced the machine out of service in 1985, in China flew the machines well into the 1990s in use. Today, no flyable more copies are available.
Overall, only 117 Tridents were built. The irony here lies in the fact that were sold by the Boeing 727, which corresponded almost completely the original Trident specification, over 1,700 copies.
In the UK, four complete Tridents have been preserved: a Trident 1C, registration G - ARPH, in Cosford, Shropshire; a Trident 2E, registration G - AVFB in Duxford near Cambridge; a Trident 3B, registration G - AWZM on display at the British Science Museum in Wroughton, Wiltshire; another Trident 3B, registration G - AWZK that dismantled in September and October 2005, for reasons of transportation in part, was transported from the previous location London Heathrow to the Aviation Viewing Park at Manchester Airport, where they should be issued. All four Tridents mentioned previously flew for British Airways.
Accidents
On July 3, 1968 two 1CS Trident, G - ARPI and G- ARPT were striped in London - Heathrow from an Airspeed Ambassador, which fell when landing out of control and shot over the apron. The five occupants of the Ambassador were killed and 28 airport employees were injured. The G- ARPI was able to be repaired, the G- ARPT had to be written off. As a cause of the accident was a defective flap that made scraping the ground the wing of the Ambassdor.
On June 18, 1972 fell a Trident 1C G- ARPI registration, after takeoff from London Heathrow with Brussels from target. All people on board were killed on impact near Staines. By the year 1988 ( Lockerbie ) it was the heaviest air traffic disaster on British soil. The cause was probably a mistake of the pilot, the front ear flaps ( buoyancy) in case of low speed import again before reaching the rate of climb.
On September 10, 1976, a Trident 3B collided, registration G- AWZT, in flight over Yugoslavia with a Douglas DC-9 Inex Adria, registration YU- AJR. All people on board the two machines were killed here. The collision was later attributed to a failure of the air traffic control. See: aircraft collision of Zagreb
On March 14, 1979, a Trident 2E of the Chinese CAAC with the registration B -274 crashed while climbing in a corporate building near Beijing. The 12-member crew and 32 people on the ground were killed. According to some sources is not a qualified pilot who stole the machine and then caused the crash.
On 31 August 1988, a Trident of CAAC (B -2218 ) at the Hong Kong airport Kai- Tak crashed into the harbor. The cause of the crash was probably a sudden visual deterioration caused by torrential rain, 6 occupants drowned.
Trivia
The nose landing gear of the Trident is exceptionally far back. The reason for this is that there is space for the computer of the automatic landing system reactive needed. In addition, the nose gear is not exactly in the middle, but it is offset slightly to the left.
The Trident was the first airliner that was standard equipped with flight recorders (from 1964).
A Trident in 1966 was the first aircraft, which carried out an automatic landing flying blind, so it was first possible to land in the fog. Fog was previously a big problem at Heathrow and led to many flight cancellations and DELAYS.
The thrust reverser of Trident could be activated in flight, so she was able, safe with a rate of descent of 10,000 feet / minute to sink (about 3050 m / minute). This option was rarely used.
The Trident reached regularly travel speeds of over 965 km / h and still makes it one of the fastest subsonic commercial airliners of all time.
Military user
- People's Republic of China People's Republic of China
- Pakistan Pakistan
Specifications
(Source: Günter Endres, William Green, Gordon Swanborough - The Big Book of passenger aircraft, engine book Stuttgart 2000, ISBN 3-7276-7129-7 )