Hawker Siddeley HS 121 Trident

Hawker Siddley Trident_1I was born in 1972, a car maniac kid, and then I got my hands on “The Black Island”.  This was the second version, reprinted in the 1960s. It had cars, especially the Triumph Herald, which I could identify on the car starved roads of India. It was sold as the Standard Herald, by the Standard Motor Products of India Ltd. This book also had detailed scenes on another mode of transport that has held me in awe – trains. This was one of my favourite Tintins as a kid. Well, a gorilla kept in captivity by the villains kept intruders at bay from the island where counterfeit notes were printed in this book. The last scene depicts Tintin departing for home aboard an airliner. The aircraft shown here is the Hawker Siddeley HS 121 Trident. It was one of the fastest sub-sonic passenger airliners with a cruising speed of 0.86 Mach or 937 km/h. Speeds which have not been breached even today.

Hawker Siddley Trident_2The Hawker Siddeley HS 121 was fast, reliable and had some very advanced features, however, it could not compete against its closest rival, the Boeing 727, because of two shortcomings, neither being technical. Firstly, it was designed to the specifications of one particular client, the British European Airline or BEA; which was incidentally a PSU (Public Sector Undertaking) owned by the British Government. As happens with most PSUs, to start with, it was reluctant to induct new technology – jet liners. It was happy with the Turbo-prop status quo. Then, when it did decide to acquire jets, it wanted them only for short hauls and kept changing specifications repeatedly. As a result, the HS 121 was introduced in the global market 2 months after the Boeing 727. The second shortcoming was actually a BLUNDER. Boeing was developing the 727. deHavilland, which had started designing the HS 121, then christened as the DH 121, wanted to cooperate with Boeing; their biggest competitor. They were considering the possibility that Boeing would drop the development of the 727 and build the DH 121 under license in the USA. They invited Boeing teams and discussed the design of the aircraft with them in detail. Finally the 727 was launched as a short to medium range aircraft with three engines. I leave you to make your own conclusions.

Hawker Siddley Trident_3The DH 121 became the HS 121 when deHavilland was taken over by Hawker Siddeley in 1960. The HS 121 flew for the first time on 09 January 1962 and the first plane was inducted by BEA on 01 April 1964. With new noise regulations coming into effect in the 1980s, all the aircraft were retired by 1995. Hawker Siddeley built and sold a total of 117 HS 121 globally. In their heydays, the HS 121 were operated by BEA, North East Airlines, British Airways and Channel Airways of UK, Air Ceylone of Sri Lanka, CAAC Airline and China United Airlines of China, Cyprus Airways, Iraqi Airways, Kuwait Airways, Pakistan International Airlines and Air Charter Service of Zaire. Military versions of the aircraft were operated by the Chinese and Pakistani Air Forces also.

Hawker Siddley Trident_6The HS 121 was also called the Trident as it had three engines and triple redundant hydraulics. Each engine operated an independent hydraulic system making the air craft extremely reliable. These aircraft were offered in both two (business and economy) and single (economy) cabin versions. The seating in economy was 3 X 3 which is the norm today, though Channel Airways had attempted a 3 x 4 configuration also, making the cabin extremely cramped. The fuselage was full metal and had a T-shaped tail. The engines were mounted aft, two in pods on the fuselage and one in the centre. The third engine was supplied air for combustion from an S-shaped air intake. Thanks to frequent changes in the specifications sought by BEA, five versions of the aircraft were built, Trident 1, Trident 1C, Trident 1E, Trident 2E and finally Trident 3B. These aircraft could seat between 101 passengers in Trident 1 to 180 passengers in Trident 3B. All aircraft except the Trident 3B were 34.98 m (114′ 9″) long. The 3B were 39.98 m (131′ 2″) long. Their wingspans varied from 27.38 m (89′ 10″) to 30m (98′).

Hawker Siddley Trident_5

Courtesy Jet Photos

All HS 121 aircraft were powered by the Rolls Royce Spey family of engines, specifically the Spey 163. The Trident 3B was actually not a Trident, as it had four engines, three Spey RB 163 and one booster Spey RB 162 for power boost when needed, especially during take offs. The Spey family of engines were developed by Rolls Royce for powering commercial airliners in the 1950s. These are low bypass turbofan engines. The various engines used with the Hawker Siddeley HS 121 generated between 46 kN (10,400 lbf) and 53.2 kN (11,960 lbf) each. The RB 162 in turn generated 23.4 kN(5,250 lbf). These engines allowed the HS 121 to take off with maximum load of 49,000 kg (107,000 lb) for Trident 1 to 68,000 kg (150,000 lb) for Trident 3B. They allowed these aircraft to cruise at speeds up to 937 km/h (582 mph) with ranges from 2,170km (1,350 miles) for Trident 1 to 4,300 km (2,700 miles) for Trident 2E. The maximum flight sealing was 11,000 m (35,000′).

Hawker Siddley Trident_4

The HS 121 had extremely advanced avionics for the time. It had a remarkable feature of a “Blind Landing System” which allowed them to land in near zero visibility. A great feature for the time for winter operations in UK where several flights were diverted due to fog. In fact, one HS 121 actually made a totally blind landing. The system was also capable of auto landing the aircraft.

The Hawker Siddeley HS 121 Trident was an exceptionally reliable, capable, fast and technically advanced aircraft which lost out due to sub-par project management and some business blunders unheard of.

 

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