Rolls-Royce Trent
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Rolls Royce Trent is a family of high-bypass turbofan engine manufactured by Rolls-Royce, developments of the famous RB211 with thrust ratings spanning between 53,000 to 95,000 lbf (236 to 423 kN). The name has also been used for a number of previous designs.
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Earlier designations
"Trent" was the name originally given by Rolls-Royce to the world's first turboprop engine. It was based on original concept provided by Sir Frank Whittle. It was derived by mating a five-bladed propeller driven through a reduction gearbox by the company's Derwent II turbojet. It first flew on an experimental Gloster Meteor aircraft in the middle 1940s.
The designation was reused again in the 1960s for the RB203 bypass turbofan which was designed to replace the Spey. It was the first three-spool engine, forerunner of the RB211 series. It was rated at 9980 lbf (44.4 kN).
Present designation
The current Trent is the development of the three-shaft RB211 family of engine. By 1987, a variant of the RB211, the RB211-524L, had been developed to such an extent that it bore little resemblance to the original RB211, other than the three-shaft layout. Rolls-Royce decided that the -524L shall be a basis of a new engine family, hence the newest Trent was born. Rolls-Royce had started naming their engines after British rivers in 1942—a practice which was revived after a thirty-year gap for the Trent.
The Trent's advanced layout provides lighter weight and better performance compared to the original RB211 and other comparable competing engines. It features the wide-chord fan and single crystal high-pressure turbine blades inherited from later generations of RB211, but with improved performance and durabilty.
Its core turbomachinery is brand new, giving better performance, noise and pollution levels. So good that it is retrofitted back to the RB211-524G/HT for better performance as compared to the original -524G and -524H. The Trent's advanced layout allows it to be fully scalable to the widest range of thrust of any current generation large turbofans.
Triple-spool advantages
Rolls-Royce RB211 and Trent uses triple-spool design rather than the more common twin-spool design. Although inherently more complex than a typical twin-spool design, superiority of this design shows at higher thrust ratings when its complexity is more than compensated by the total improvements achieved. Excellent development progress from the original RB211-22 to the current Trents, has turned Rolls-Royce's higher thrust turbofans into performance leaders in their respective thrust ratings which translates into a market leadership figures of excess of 50% of all total widebody orders in 2004.
As thrust rating increases, the high-pressure compressor increases in lenght resulting in a more complex airflow which increases the probability compressor airflow instability. The twin-spool engine requires complex airflow control devices to prevent this. The triple-spool design reduces this problem by splitting the high pressure compressor into two , thereby increasing the total engine compressors to three. By doing so, each compressor will now rotate at their own optimum speed making the engine's airflow very stable over a wide range of speeds.
A triple-spool design features higher compression ratio as compared to the twin-spool design making them generally shorter and lighter than a twin-spool equivalent. For example the Rolls-Royce Trent is lighter than its General Electric's GE90 equivalent. The lower individual spool rotation speed leads to a reduced parts-count resulting in longer life and reduced maintenance costs.
And importantly, the triple-spool design allows design flexibility by simply resizing the compressors and turbines to accomodate different thrust ratings. The Trent's broad spread of thrust ratings for example, spans from the 56,000 to 107,000 (and may be pushed beyond 110,000) pounds thrust. Compare this with Pratt & Whitney's PW4000 series (56,000 to 90,000 pounds thrust) , the GE's CF6-80 (56,000 to 68,000 pounds thrust) and GE90 (84,000 to 115,000 pounds thrust). This allows Rolls-Royce to offer engines earlier than others. For example the Trent is offered earlier to Boeing for the latter's Next Generation 747, 777-200LR, 777-300ER and the 787 and to Airbus for its A340-500/600 and A380.
Variants
Trent 500 Series
The Trent 500 family is designed to power the Airbus A340-500 and A340-600. It comes in 2 thrust ratings, 53,000 and 56,000 lbf (236 to 249 kN). The Trent 500 features a Trent 700 wide-chord fan together with a core scaled from the Trent 800.
Trent 600 Series
The Trent 600 family is designed to power the future Boeing 747 aircraft developments. It is actually a refinement of the original RB211-524L. Rolls Royce claims that it performs better than any current 747 engine.
Trent 700 Series
The Trent 700 family is designed to power the Airbus A330. It powers all variants of the A330. It features a fan with a diameter of 2.47 m. It comes in 2 thrust ratings, 67,500 and 71,000 lbf (300 to 316 kN). It entered service on Cathay Pacific A330 aircraft in March, 1995.
Trent 800 Series
The Trent 800 family is designed to power the Boeing 777. It powers the 777-200, 777-200ER, and 777-300 variants. It is available with thrust ratings spanning 75,000 to 95,000 lbf (334 to 423 kN).
It features 2.89 m diameter fan. With its three-shaft configuration and hollow titanium wide-chord fan makes a Trent-powered Boeing 777 weigh up to 3.6 metric tons less than General Electric and Pratt & Whitney-powered versions. It is currently the most popular 777 engine with 44% market share, but the sales success of Boeing's 777-300ER, only available with General Electric's GE90, may result in the Trent 800 being eclipsed.
Trent 8104
Originally designed for the 777-200LR and 777-300ER (both part of the 777X project), it comes in two thrust ratings, 104,000 and 114,000 lbf (463 to 507 kN) and has been tested up to 117,000 lbf (520 kN).
Rolls-Royce offered the 8104 to Boeing earlier than other manufacturers. Boeing had a requirement that the participating engine developer assume a risk-sharing role on the overall 777X project. Rolls-Royce was unwilling to do so; General Electric was, however, and Boeing selected advanced developments of the GE90, the GE90-110B and GE90-115B. This relegated the 8104 to the role of a demonstrator engine. It featured swept-back fan blades and a host of new technologies such as contra-rotating spools.
Trent 900 Series
The Trent 900 family is designed to power the giant Airbus A380 where it is the launch engine. It comes in two thrust ratings, 70,000 and 76,000 lbf (311 and 338 kN) but is capable of achieving 84,000 lbf (374 kN). It features a significant amount of technology inherited from the 8104 demonstrator including the 2.95 m diameter swept-back fan.
The engine's control system is provided by Hamilton Sundstrand, a United Technologies (UTC) company. UTC is also the parent company of Pratt & Whitney, who, with GE Aircraft Engines, is partnering to produce the Engine Alliance GP7200, the other engine available for the A380. This type of cooperation among competitors is prevalent in the aircraft market as it provides for risk sharing among them and diversity in source countries, a significant factor in an airlines' choice of airframe and powerplant.
The Trent 900 made its maiden flight on May 17 2004 on Airbus' A340-300 testbed, replacing the port inner CFM56-5 and dwarfing the remaining engines. A380 customers which have selected the Trent include Virgin Atlantic, Qantas, Singapore Airlines (already the largest Trent operator) and Lufthansa.
Trent 1000 Series
On April 6, 2004 Boeing announced that it had selected two engine partners for the 787, Rolls-Royce and General Electric. Initially, Boeing toyed with the idea of sole sourcing the powerplant for the 787, with GE being the most likely candidate. However potential customers demanded choices and Boeing relented.
The Trent 1000 (as well as the GENX) are both evolutionary derivatives of existing designs, whereas the discounted competitor, the Pratt & Whitney engine was to be an all-new design.
The technology found in Trent 8104 demonstrator is used extensively. The Trent 1000 is a bleed-less design, with power offtake from the intermediate-pressure spool instead of high-pressure spool found in other members of the Trent family, to fulfill the Boeing requirements of a "more-electric" engine. Bypass ratio is increased by having swept-back fan, smaller fan hub which increases the fan effective diameter and by having contra-rotating high-pressure spool; all this increases the engine airflow. More monolithic parts are employed to reduce parts count for lower maintenance costs.
The first run of the Trent 1000 is expected in early 2006. In June 2004, the first public engine selection was made by Air New Zealand, selecting the Trent for its two firm orders. The airline has options for 16 more 787s. In the most significant 787 order, that of Japan's All Nippon Airways, Rolls-Royce was selected as the engine supplier on October 13 2004. ANA's 50 firm aircraft order is the largest to date and has established Rolls-Royce as the leading engine supplier (so far) for the 787 program. The deal is valued at $1Bn (£560m).
Both Rolls-Royce and General Electric have confirmed that they are in talks with Airbus with regard to supplying their new generation engines for Airbus' competitor to the 787, dubbed the A350.
MT30
Marine Trent 30 is a derivative of the Trent 800, (with a Trent 500 gearbox fitted), producing 30 megawatts, (MW), for maritime applications. The current version actually produces 36 MW, and is not actually a turbo fan engine, instead using the T800 core to drive a power turbine which takes power to an electrical generator or to mechanical drive such as waterjets or propellors.
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