Rolls Confident of Trent XWB Performance and Popularity

 - July 12, 2014, 9:00 AM
R-R claims the Trent XWB’s advanced compressor aerodynamics deliver module weight savings of 15 percent through blisk technology.

Rolls-Royce is confident that other customers will take up the 70 Airbus A350-900XWB and -1000XWB production positions released when Emirates Airline canceled its order on June 1, and says demand remains strong for the new twin-aisle twinjet, which is powered exclusively by R-R Trent XWB engines. The loss reduced the manufacturer’s orderbook by £2.6 billion (excluding the value of “TotalCare” support contracts), or about 3.5 percent.

Before the decision was announced, R-R (Hall 4 Stand H3 and Chalet D3) had put A350XWB orders at 812, including 189 A350-1000s, from 40 customers. The UK engine company also has endured canceled A350-800XWBs, orders for which fell to fewer than 40 earlier this year.

Despite the order disappointments, R-R stated that it is “very pleased” with demonstrated engine performance. Production of the 84,000-pound-thrust Trent XWB-84 is established and assembly of the first more-powerful 97,000-pound-thrust XWB-97 variant began in June.

XWB-84 manufacture for the initial A350-900 is planned to accelerate from the current two per month to one per day by the end of this decade or the early 2020s, according to Trent XWB marketing head Tim Boddy. He said relatively little time would be required to prepare to run a 73,000- to 79,000-pound-thrust XWB-79 for the A350-800; R-R could fly an example in the middle of next year if initial suggestions of a 2016 entry into service are confirmed. (Airbus has not yet accorded development status to this smallest variant and neither company includes the model in projected timelines.)

Seeking Maturity

R-R has established dedicated Trent XWB-84 and -97 program teams to translate lessons from testing into engine maturity as suppliers increase production rates and the manufacturer develops service capabilities covering parts, spares and training, designed to “build inherent support,” said Boddy. The Trent XWB-97 final design concept was completed last year and R-R expects to begin initial production in six to nine months’ time, ahead of projected 2017 service entry.

Last month, the first two pairs of Trent XWB-84 production units–engine serial numbers (ESNs) 21019/21020 and 21021/21022 were delivered to Toulouse for installation on the initial A350-900s for launch customer Qatar Airways–manufacturer serial numbers (MSNs) 006 and 007, respectively.

R-R said it is “really very pleased” with Trent XWB-84 performance during A350-900 testing, with some 1,620 aircraft hours flown during about 430 flights. So-called full-spectrum testing has been completed, including climatic and environmental work in extreme cold, hot, high and humid meteorological conditions in Bolivia, Canada, Martinique, Qatar, Singapore and the U.S., and last month in tropical weather in the United Arab Emirates.

By June, specific powerplant testing had seen 6,700 engine hours/13,200 cycles logged with 14 Trent XWBs in work at six sites in Europe and North America, including simulated altitude work at Edwards AFB in California, initial thermal-endurance exercises in Madrid, Spain, and cold starting in Canada. R-R has another thermal-endurance test to run before service entry late this year, and additional running later as it works to build engine experience.

Route Proving

One example is testing in preparation for extended twin-engine operations (Etops). Airbus is seeking clearance at service entry for A350s to be permitted to operate at up to six hours single-engine cruise range from the nearest available airports (up from an earlier plan for 350 minutes’ clearance).

In what Boddy termed the “ground version of Etops,” R-R has completed the first of three “diversion” test cycles run like airline operations on ESN 20011/1, comprising three blocks of 1,000 simulated 30-minute flights to be followed by a maintenance shop visit demonstration. Testing includes on-wing maintenance and inspection routines. Previous plans had included 4,250 such cycles, and Boddy said that by early June 1,465 cycles had been completed.

Planned route-proving flights to the Arabian Gulf will provide an opportunity to complete high-temperature operations, with R-R saying that no engine issues arose during earlier hot and cold tests with A350 MSN002. Using the McKinley climate-testing chamber at Elgin AFB in Florida, Airbus has completed engine runs at 45 degrees C/15 percent humidity and at -40 degrees C/F.

R-R said last month that it had begun building the first of a projected series of up to 14 test units of the more powerful Trent XWB-97. The high- and intermediate-pressure compressor (HPC and IPC) assemblies were complete and the manufacturer said, also in June, that most engine modules would be complete in a few weeks. It expects to fly the XWB-97 engine on the Airbus A380 flying testbed in late 2015.

According to R-R, the Trent XWB-97’s functional capability is built on the foundation of the XWB-84 and it plans to demonstrate -97 conditions on a baseline engine. Testing is scheduled to include HPC and IPC efficiency and operability, high- and intermediate-pressure turbine efficiency, fan efficiency and flutter, and combustor relight and emissions.