Farnborough Air Show

Rolls-Royce Upgrades In-service Trent Engines

 - July 15, 2014, 6:00 AM
The Trent 900EP2 is the new-build standard for the engine that is to power the Airbus A380.

Rolls-Royce (Hall 4 Stand H3) is maintaining a continuous effort to improve in-service Trent performance, both for production engines and as retrofits. The newest version of the Trent 1000–the TEN for the Boeing 787-8,-9 and -10–is to be certified next year.

On the Airbus A330, a further upgrade, the Trent 700EP2, is expected to cut fuel burn by another 1 percent when it is available in 2015 or 2016. “Changes include new stators in the intermediate-pressure (IP) and high-pressure (HP) compressors, reworked with 3-D aerodynamics,” head of Trent customer marketing Peter Johnston said during a briefing ahead of the Farnborough Airshow. Build modifications improve clearances and sealing. The Trent 700EP had already reduced the fuel burn by 1.1 percent.

Rolls-Royce will offer a 68,000-pound rated Trent 700 for the A330 Regional, optimized for two-hour sectors. Because of its lower thrust, “maintenance costs will be lower but the engine can easily be upgraded,” Johnston said.

The UK-based manufacturer is claiming a 63-percent market share for the Trent 700, powering a fleet of 605 delivered A330s. The current annual delivery rate of the Trent 700 is 185.

The Trent 900EP2 is the new-build standard for the engine that is to power the Airbus A380, Johnston said. He suggested Airbus might hand over an aircraft with mixed engine configurations. An airline would want to have consistent engines on a given aircraft but one, two or three EP2s is better than zero, Johnston said.

The Trent 900EP2 incorporates some advancements over the Trent 1000 and Trent XWB. “This is the way we want to go in the Trent family,” Johnston said. Such optimization affects fan blade-tip clearance, turbine case cooling and low-pressure turbine sealing. Elliptical leading edges have been integrated to a stator. Engine tests are complete and the new standard is to deliver a 0.8-percent fuel burn reduction on the A380, according to Rolls-Royce’s predictions.

For the Boeing 777, the Trent 800 is being improved as well. The Trent 800EP is now in operation with elliptical leading edges on IP and HP compressor blades. The claimed outcome is a 0.7-percent fuel-burn benefit.

Similar modifications on the Trent 500–for the out-of-production A340-500/600–yield 0.5 percent. The Trent 500EP+ is being offered as a retrofit kit. A support agreement with Lufthansa Technik is “aligning the Trent-powered A340’s operating costs with big twins,” Johnston added.

Asked whether operator feedback is generally consistent with fuel burn predictions, Johnston gave an affirmative but cautious answer. “We are getting the numbers we were hoping for but it is not easy–are we talking about the same aircraft weight? The same altitude?” he said. At least with the Trent 500EP+, three different sources have given Rolls-Royce homogeneous information on turbine temperatures, compressor efficiencies and fuel flows.

The Trent 1000-TEN ran for the first time late in May. Able to provide up to 78,000 pounds of thrust, it is targeted at the 787-10 but will be used with other members of the 787 family. It will enter into service on the -8 and the -9 from 2016 and the -10 from 2018.

Certification is pegged for late 2015. The main expected benefit is a 3-percent cut in fuel burn, compared to the earlier Package B version. Recently completed demonstration tests include advanced seals, disk architecture and advanced fan case dressings.

The so-called dressings consist of carbon wraps with weaved-in pipes and wires. This “more elegant” design, as project director Gary Moore put it, translates into a quicker assembly. Weight is reduced thanks to the suppression of brackets, clips and corresponding fixed parts on the metal case, he explained. “Maintainability is improved, too,” Moore added.

Other features of the Trent 1000-TEN include new IP and HP compressors, for more efficiency. The new IP compressor also has more flow capacity to enable more thrust. The new HP compressor has been proven on the NEWAC demonstrator program and the Trent XWB, Moore said. Proven on the Trent XWB, too, are lighter and more efficient bladed disks (blisks).

The new HP turbine has an advanced cooling system to enable more thrust and more efficiency. Finally, the HP spool has been fitted with an adaptive cooling system. It reduces fuel burn and helps retaining engine performance.

The Boeing 787’s Trent 1000 is the most recent Trent model in revenue service, and Moore expressed satisfaction, giving favorable numbers. As of early June, no in-flight shutdown had been recorded and reliability stood at 99.98 percent. The Trent 1000 is flying on 51 aircraft.

In September 2013 Rolls-Royce received the certification of the Trent 1000 Package C for the 787-9, for which it will be the launch engine.