Originally published by Guy Norris for Aviation Week on May 30th 2016.
Less than two years after committing to developing the Trent 7000 for the reengined Airbus A330neo, Rolls-Royce has completed first ground tests on the initial powerplant and is preparing to assemble the first flight-test engines.
Such a fast-paced program is only possible because the Trent 7000 is adapted directly from the Trent 1000 TEN, the latest version of the engine family in advanced development for the Boeing 787. While Rolls was previously successful in applying virtually identical models of the RB.211 to multiple platforms, this is the first time since the original Trent 700 was introduced on the A330 in the 1990s that the manufacturer has been able to leverage this degree of reuse with a single member of the Trent family.
The engine, scheduled to debut on the first A330-900neo with TAP Portugal in late 2017, is designed to reduce specific fuel consumption by 10% compared to the Trent 700. Thanks largely to its 112-in.-dia. fan which gives it double the bypass ratio of the 97.5-in. fan diameter Trent 700, the variant is also designed to be about 10 dB quieter. “Because of this it looks like a much bigger engine,” says Peter Johnston, head of customer marketing for Airbus at Rolls-Royce.
“It has been quite impressive that Airbus has managed to mount the Trent 7000 on the A330 without having to alter the landing gear, or [without us needing] to flatten the nacelle [as] we did with the Trent 700,” he adds. To achieve a snug fit the engine is mounted forward and closer to the wing. “It shows how installation aerodynamics has improved over the past 20 years. The Trent 700 was as close to the wing as they dared go in those days,” says Johnston.
“It is quite a tight program on the Trent 7000 because Airbus wanted to get the aircraft into production as quickly as they could, but in terms of technical activity it’s fairly low-risk,” says Johnston. Compared to the Trent 1000 TEN, the engine differences are “as few as humanly possible. It is one of the few examples where we have two engines with even the same part numbers. There are changes for the interface on the aircraft, or where that interface forces a change in the engine,” he adds.
The main changes relate to interfaces with the A330neo’s electronic bleed air system which connects the originally nonbleed designed systems of the Trent 1000 with the pneumatic and anti-icing requirements of the A330neo. “This goes on the intercase, and of course the same space was real estate on the Trent 1000 [that] we used for other systems, so everything has to be redressed around the externals. We also redressed the core externals and modified the intercase and combustor outer casing for the same reason,” says Johnston, who notes the addition of different oil system pumps and a new gearbox, which also happens to be the first product of Aero Gearbox International (AGI), the recently formed joint venture between Rolls and Safran’s Hispano-Suiza unit. The initial engines have run with standard Trent 1000 gearboxes, but the AGI unit will be installed for the start of certification testing.
Because of the limited changes, only four development engines are required for the Trent 7000 test program. The first of these, 7001, first ran last November and has since completed an altitude test campaign at Arnold Engineering Development Center in Tullahoma, Tennessee. These were aimed at verifying specific fuel consumption (sfc), in addition to general icing tests. “It was something Airbus was keen on doing, though we have never had an icing problem. The recent [General Electric] GEnx icing issues sharpened Airbus interest, and because the inlet is slightly different from the Trent 1000 inlet aerodynamics they couldn’t take previous icing results and say it was OK,” says Johnston. Tests showed “we are on track for sfc and there were no discoveries that gave us pause for thought.”
The second engine, dubbed L73, is “ready to go and is now attached to the test pylon,” he says. The engine will be used for functional and operability testing and will be accompanied by the type test engine, L72, currently undergoing module build. Parts for the fourth engine, L74, are currently coming together in Derby, England. The engine will join the test program later this year and be used to perform cyclic and ETOPS work. “We are also just getting ready to build the first two flight-test engines. Airbus will have seven flight-test engines altogether, but they won’t use the A380 flying testbed. The TEN will have flown on our [Boeing] 747 and the 787 before the Trent 7000 flies on the A330, so Airbus does not need a safety-of-flight check,” he adds.
With the certification effort on the Trent 1000 TEN considered the pacesetter for the Trent 7000, Rolls expects to start the type test evaluation “later this quarter,” says Johnston. “Then we go through to engine certification early in 2017 and in time for first flight of the A330neo, which is around the same point.” Production deliveries are due to begin later in 2017 with the first aircraft going to TAP Portugal at the end of that year.
To date the A330neo has attracted orders, commitments and letters of intent for 204 aircraft from 11 airlines and leasing companies. TAP has 14 orders for the A330-900, the reengined version of the A330-300 that will be the first of the new family to be delivered. The first of the reengined A330-200 variant, dubbed the A330-800, will begin deliveries at the end of 2018. “It is going quite well and there is a lot of interest out there still to be captured,” says Johnston, who adds “there is a 1,000-aircraft opportunity out there and this is just the beginning.”