n another of those peculiar aviation ironies, is embarking on a new engine for the latest version of the with technology developed for not one but two engines originally intended for two A330 replacements, the and .I
Yet Rolls largely owes its exclusivity on the A330neo to the success of its current A330 engine, the, which is one month short of celebrating 24 years since its first run. Against competition from ’s -80E1 and Pratt & Whitney’s , the Trent 700 has carved a big slice of the A330 market which, combined with Rolls’s exclusive position on the A350 with the engine, helped the engine maker to leverage the same position on the A330neo.
To develop the newly named Trent 7000, Rolls-Royce has embarked on a fast-track test and development program to support the big twin’s entry-into-service target of late 2017. Although most new engine development programs take 5-6 years on average to come to market, Rolls is halving the time by basing the Trent 7000 on the -TEN, the latest version of the family, which is currently in development for the 787.
The new engine will run for the first time in 2015 and be flight tested on Rolls’sflying testbed in 2016. A decision on whether flight tests will take place at Airbus before mounting on the A330neo is yet “to be determined,” says Rolls-Royce’s customer marketing vice president, Richard Goodhead. The engine, rated at 68,000-72,000 lb. thrust, will power both new variants, which will be called the A330-800neo and -900neo.
The Trent 7000 is “a relatively low-risk program,” says Goodhead, adding that engine certification is targeted for the first quarter of 2017. While it weighs considerably more than the Trent 700, Rolls says the performance benefits of the newer technology Trent 1000-derivative will far exceed the penalties of the larger engine’s drag and mass. The engine will be cantilevered further forward and higher on the wing pylon to ensure adequate ground clearance and load distribution, Goodhead notes. Compared to the 97.5-in. fan diameter and 5:1 bypass ratio of the current Trent 772, the Trent 7000 will have the same 112-in. fan diameter and 10:1 bypass ratio of the newest787 engine.
Advances in the core design give the new engine an overall pressure ratio of 50:1, compared to 36:1 on the Trent 700. Combined with the higher bypass ratio, the Trent 7000 specific fuel consumption is 10% lower than that of the baseline engine.
“When that’s integrated with the airframe changes of the A330-800/900neo, it will result in a 14% lower fuel burn per seat,” says Goodhead. The bigger fan will also significantly cut noise, enabling the A330-800/900neo to meet stiffer London airport “quota count” (QC) noise regulations of QC1/0.25 for departure and arrival, respectively, compared to the QC2/0.5 capabilities of the current aircraft.
The Trent 7000 version of the -TEN also will be adapted to power the A330’s pneumatic and electric systems with the addition of bleed offtakes and a different power gearbox. The changes will be based on standard offtake systems such as the one used in theengine for the , which takes bleed air for environmental control and wing anti-icing from offtake ports in both the intermediate-pressure (IP) and high-pressure (HP) spools, depending on demand level and flight phase. Other adaptations related to the bleed system will include modifications to the front bearing housing assembly to prevent the potential for oil-related vapor from entering the air system.
Trent 7000 development will follow directly on from the Trent 1000-TEN, which made its first run in late May at Rolls’s Derby, England, facility. The engine will be certified to 78,000 lb. thrust for all versions of the 787 by the end of 2015. The first -TENs will enter service on the 787-8/9 in 2016, and on the 787-10 in 2018. Launched at the Farnborough air show two years ago, the Trent 1000-TEN incorporates features from the Trent XWB developed for the A350, as well as the company’s Advance technology program. Initial demonstrations of some -TEN features have already been completed, including advanced seals, a new fan case dressing system, revised Trent XWB-based disc architecture and cyclic tests of the new case dressing on a Trent 1000.
Both the Trent 1000-TEN and 7000 engines incorporate a new eight-stage, higher-flow IP compressor and a new six-stage HP compressor derived from the XWB engine. The configuration was originally tested in the European New Engine Core Concepts (Newac) technology program and includes blisks in the front three stages. The entire HP section will be cooled by an adaptive system that modulates the volume of bleed air from the HP compressor using a “vortex amplifier,” which relies on an air-based valve system to control the flow. By modulating the cooling air volume off-take, the system uses only what is needed at specific times, thereby increasing efficiency.