With the Airbus A350-900 now in service, engine producer Rolls-Royce (R-R, Chalet 93) is turning its attention to the A350-1000 and the Trent XWB-97 engine, which is based on the -900’s Trent XWB-84. There also still is a significant “industrialization” effort going on for the -84, as production ramps up and more airlines take delivery. The A350-1000 is due to enter service in 2017.
Simon Burr, who was promoted to be R-R’s chief operating officer for civil large engines in May, spoke to reporters three weeks ago referring to his experience running the Trent XWB program until recently. He said the XWB-97 would make its first flight next year on Airbus’s A380 flying testbed (MSN001), and has “the largest fan Rolls-Royce has ever produced” –118 inches in diameter.
For now, the first test engine (one of four that have run to date) completed 150 hours of ground testing since its first run in July 2014. “It’s already gone to 99,000 pounds force,” said Burr. He added that engine (Serial No. 20021) is now being rebuilt to be ready for bird-ingestion and rail/hail tests this summer.
The key engine, however, is the flying testbed (Serial No. 26000), which will be close to the production standard and will be the first engine to fly. “The engine is coming together and will run [in June] and will be delivered to Toulouse in July so Airbus can pod it. This is a big milestone because in creating the FTB [flying testbed] you have to create all the tests associated with the production engine.” With respect to a target certification date Burr would say only that, “It will be done when it’s ready, but way in advance of the aircraft flying…and that’s due to be in the second half of next year.”
After the first 150 hours of engine runs the company made “some adjustments mainly to the combustor thermal profile,” said Burr. Of the other test engines, 20022 will be used for endurance, 20023 for performance and fan testing, 20026 for icing and maturity, 20024 for the turbine and air system, and 20025 for telemetry testing.
Compared with the -84 the -97 engine is, obviously, larger with more thrust. It will “turn faster and run hotter to get the additional thrust,” said Burr, who was quick to say that “the engine is still very comfortable.” In addition, he said, the fan has been “tweaked” aerodynamically.
The result has been to obtain another 13,000 pounds of thrust with the same fuel efficiency, with the fan turning 6 percent faster than with the -84 to get a higher volume throughput. The core of the engine is scaled up by 5 percent over the -84 and has unshrouded HPT (high-pressure turbine) blades. Overall, however, the company has come down on the side of commonality wherever possible, with 80 percent of line replaceable units being common on the XWB engines.
XWB-84 in Service
With the first A350-900s having entered service with Qatar Airways, R-R is now working on an XWB-84 “maturity program,” alongside the industrialization. “Vietnam is shortly to get their first aircraft; the engines have been delivered already. And we’ve built the first engine for Finnair…and TAM will be toward the end of the year. We’re 100 percent on time on delivery for our engines,” said Burr.
The industrialization is “very important because of the order book.” (Overall, the 780 A350s have been ordered by around 40 customers). “Rolls-Royce has invested huge amounts in its facilities, such as UK Discs.” This plant in Washington, Tyne and Wear, UK, is designed to produce 2,500 fan and turbine discs a year. Meanwhile, R-R has “put in a pulse line [for engine assembly] in Derby, which Burr described as “a big step forward in how we build our engines.” This was matured first in the Trent 1000 facility in Singapore; that engine powers the Boeing 787.