FLUG REVUE April 2003: Trent 900 tests to start

TRENT 900 TESTS IMMINENT

By Patrick Hoeveler

The engineers responsible for final assembly of the first Trent 900 might as well demand an admission fee, given the constant stream of Rolls-Royce staff into the experimental workshop to marvel at the company's new flagship. 17 March is a significant date, for it is on that day that engine number

90001 is supposed to be first run on the large test stand 57 in Derby, which has a capacity of handling engines with a thrust of up to 622kN.

However the Trent 900 is a long way off from these hitherto unattained dimensions. The power plant for the Airbus A380 is expected to be certificated in October 2004 with a rating of 342kN which can be raised to 356kN for hot and high operations. Robert Nuttall, Vice-President Marketing, believes there are also opportunities for growth up to a thrust of 373kN. "A year after the first tests we will know more.” In any case, if the power output was to be increased, the nozzle guide vanes would have to be modified to direct more air into the core.

The first, primarily functional tests will then be followed by performance tests, in which a total of seven engines will be used. The modules for the second and third Trent 900's are already in the system. However, final assembly of these engines will not commence until after successful completion of 90001's green run. "That ensures that any eventual problems during the first run could be eliminated directly before assembly of the next engines,” says Nuttall.

The first type test will then entail 150 hours of operation under high loads and is scheduled for completion in November. This will be followed by bird ingestion testing in December. Finally next year Rolls-Royce and Airbus plan to capitalise on their good experience in the Trent 500 programme by carrying out 50 hours of flight testing on the aircraft manufacturer's A340 testbed. The new engine model should enter service on the A380 at the beginning of 2006.

One of the key arguments Rolls-Royce is using to market the Trent 900 is the risk reduction by the family concept: "We don't want to use too much new technology at once,” explains Nuttall. Thus the Trent 900 possesses all the advanced features of the 500, such as the use of 3-D computational fluid dynamics, a tiled combustor and end wall profiling. In this technology patented by Rolls-Royce, the turbine end walls are specially shaped to avoid losses from secondary air flows.

In addition, the A380 powerplant contains a fan with 24 swept blades, which is the biggest fan Rolls-Royce has ever built. Another new feature is use of the principle of contra-rotation. In contrast to the other stages of the engine, the high-pressure system, when viewed from the front, rotates in an anti-clockwise direction. In this way the engineers optimise the airflow. As a result the weight and number of guide vanes can be reduced. All in all, according to Nuttall, these modifications improve efficiency by 1.5 percent.

According to Rolls-Royce, the Trent 900 is chosen for 57 percent of the announced A380 engine orders. Included are the ten planes ordered by the leasing company ILFC as well as the orders from Singapore Airlines (ten A380's), Qantas (twelve), Virgin (six) and Lufthansa (fifteen). The rival product from the Engine Alliance, consisting of GE Aircraft Engines and Pratt & Whitney, has so far been chosen by Air France (ten aircraft A380), Emirates (22) and FedEx (ten). The GP2700 is expected to have its first run on February 15th, 2004. The first components are already undergoing testing. Malaysia Airlines (six aircraft) and Qatar (two) have not yet announced their choice.

The decision by Emirates, a good Rolls-Royce customer, in favour of the American product came as a surprise to the industry, as did Lufthansa's choice of Rolls-Royce, given that most of its engines are from GE. Now the German flag carrier will operate the Trent 900 on its A380's in addition to the Trent 700 and Trent 500 on its A330's and A340's respectively. Rolls-Royce and Lufthansa Technik recently founded a joint venture company to handle maintenance of these engines. The new company N3 Engine Overhaul Services, named after the speed designation for the intermediate pressure shaft, will get off the ground in 2007 with a workforce of 250. Engines operated by Lufthansa and those which are the subject of Rolls-Royce's total care packages will account for approximately 40 percent of the volume of work each. The location of the joint venture will be announced by 2004 after a Europe-wide invitation to tender.

No doubt Rolls-Royce will introduce other new technologies in the next member of the Trent family. The company is currently in discussions with Boeing and possible customers regarding key data for the aspired-to "most effective engine” for the future 7E7 airliner. "The time frame gives us another two-and-a-half years to use new features.” According to Nuttall, an electric starter is one possibility. The requirements for the new member of the Trent family in the thrust range of 289kN are to be defined in a year's time. In the meantime no designation has yet been assigned. The designation "600” is already reserved for the Trent 600 for the new versions of the 747, although there is not much work on this programme for the time being. "The decision is up to Boeing,” says Nuttall. However, the aircraft manufacturer has hinted that the 7E7 engines might also fly in future variants of the 747 (see separate article on the 7E7). But so far Boeing has not yet found any launch customers for the modified jumbo.

From page 86 of FLUG REVUE 4/2003

Last updated 4 March 2003

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