British engine manufacturer Rolls-Royce (R-R) is “really happy” with good Trent XWB-97 performance results that have generated a “high confidence of achieving targets.” By mid-June, test engines had completed more than 1,350 hours and 1,950 cycles, built “upon the solid foundation of Trent XWB-84,” said head of marketing Tim Boddy.
The Trent XWB is the exclusive powerplant for the Airbus A350 XWB, for which the airframe manufacturer had (by June) orders from 42 customers for 802 aircraft, including 181 stretched, XWB-97-powered A350-1000 models and 16 shorter-body A350-800 variants. By then, 24 XWB-84-engined A350-900s were flying with six operators: Qatar Airways, Vietnam Airlines, Finnair, LATAM, Singapore Airlines, and Cathay Pacific.
Overall, the Trent XWB engine fleet had completed more than 37,800 individual flights, logging very close to 110,000 engine flight-hours. The leading engines had recorded 1,127 flights and almost 6,400 hours, respectively. Boddy said that the fleet is “working well,” with R-R “very satisfied” after some 18 months of operations with what he described as “the best-ever” entry into service.
Following what the executive terms “major industrial investments,” R-R (Chalet D3, Hall 4 Stand B18) is establishing a second Trent XWB production build line at its Derby, UK main base, to support planned higher assembly rates for up to 20 engines per month (to power 10 A350s). Manufacture is being ramped up over about two years from 2.6 a week in late 2015 to 4.9 (including about one TXWB-97) a week before 2018.
R-R expects to build one XWB per day by next year, having successfully achieved a parts-supply and production trial that saw “four engines assembled in four days.” Maximum production should reach 6.4 XWBs per week by mid-2019, with monthly output comprising about 17 XWB-84s and around ten -97s.
By last month, some 139 engines were “in the production cycle and, with the manufacturer maintaining a current throughput of three a week, perhaps as many as 165 are now undergoing assembly or have been delivered. To demonstrate production capacity, which R-R is “constantly testing,” the company will try “to ‘pulse’ at five a week.”
Meanwhile, Boddy says that engine-maker is “building in” technology by taking what he termed “development learning” from XWB-97s (that generate up to 97,000 pounds of thrust) back into the XWB-84 (up to 84,000 pounds thrust)—an exercise the company hopes will yield a 1 percent improvement in specific fuel consumption in the planned Trent XWB-84 EP (Enhanced Performance) model.
For this variant, R-R has a series of modifications and changes in different areas of the engine:
– Intermediate- and high-pressure compressors: Improved stator-blade aerodynamics;
– Combustor and high-pressure turbine: Redesigned combustor port, “low-flow” turbine blade and nozzle guide vane, increased hade-angle blade tip, and reduced cooling-seal segment;
– Intermediate-pressure turbine: “Low-flow” turbine blade and nozzle guide vane, and re-balanced stage loading;
– Low-pressure turbine: Improved inter-stage sealing, and aerodynamic redesign around higher radius; and
– Whole engine: Re-profiled outer-turbine annulus, “high-flow”/high-authority turbine-case cooling, secondary air system optimization, and improved sealing.
Looking to the Future
Five months after announcing the XWB-84EP, R-R already has its eyes on the next events in what it dubs a “continuous improvement journey.” An initial engine run in early 2018 will follow a critical design review for the new variant in the latter part of next year—for which Singapore Airlines is the launch customer.
R-R hopes to see the engine making a first testbed flight in early 2019 before entering service aboard ultra-long-range variants of the A350-900 early in the following year, according to general program timelines. The company expects to “deliver the first Trent XWB-84EP to Airbus by the end of 2019,” said Boddy.
The A350-1000’s Trent XWB-97 powerplant sports a higher-flow fan, larger core, and “high-capability” turbines, while maintaining the earlier variant’s aerodynamic lines. More than 70 percent of XWB-97 certification tests have been completed, with R-R having operated as many as six engines simultaneously. The work began with a 150-hour first engine run that Boddy believes provided a “very good demonstration of maturity.”
Regarding further Trent XWB development to address any stretch beyond the A350-1000 (in a possible new model variously dubbed A350-1100, -2000, and -8000), Boddy said that R-R is “ready to offer a technology solution” to meet any requirement and is seeking to provide “maximum commonality with all the thrust you need.”
(culled from ainonline.com)
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