As clearly indicated by the $4.7 billion in new widebody engine deals announced at the Paris air show, Rolls-Royce continues to bank heavily on the higher-value big-engine market.

With around half of this newly signed business tied up in aftermarket support and sales of existing products, the company is stepping up its wide-ranging campaign to plow back technology from the latest-generation large turbofans into the rest of the in-service Trent family.

What began as a relatively targeted performance upgrade for the Trent 700 on the Airbus A330 in 2009 rapidly spread to include fuel-burn improvement packages for the Trent 500-powered A340-500/-600, Trent 800 on the Boeing 777 and Trent 900-powered A380. While some features have been developed as a kit for retrofit, the bulk of each package has evolved to become the new-build configuration or is poised to transition to the standard bill of material as test and development are completed.

The Trent 700 and 900 upgrades form a key element of Rolls's battle against competing General Electric and Pratt & Whitney offerings on the A330 and the Engine Alliance teaming of the two U.S. engine makers on the A380. With no new active sales campaigns for the 777-200ER, and none at all for the now-closed A340 production line, the Trent 800 and 500 upgrades are aimed at reducing operating costs and sustaining residual values.

While details of each upgrade package differ from engine to engine, all share fundamental improvements in aerodynamics and tighter sealing. Common to all is the introduction of elliptical leading edges to blades in the intermediate pressure (IP) and high-pressure (HP) compressor. Pioneered on the HP compressor of the International Aero Engines V2500 as part of the SelectOne upgrade in 2008, the redesign delays turbulent flow and improves the boundary layer over the compressor blades, boosting overall efficiency and reducing fuel burn.

Now more technology from the 787's Trent 1000 engine, and the recently certificated Trent XWB-84 for the A350 is finding its way into the upgrade cycle, says Peter Johnston, head of customer marketing for large civil engines. The next upgrade package for the company's best-selling A330 engine, the Trent 700 EP2 (enhanced performance), will include three-dimensional aerodynamic changes and sealing improvements leveraged from the latest Trent family developments. Coming on the heels of the first EP kit, which reduces fuel burn by up to 1.3% on new-build engines and 1.1% on less comprehensively upgraded retrofitted powerplants, the EP2 is scheduled to be introduced in 2015.

With more than 500 Trent 700-powered A330s in service, the fleet is poised to overtake the RB211-535-equipped Boeing 757 as the largest in the Rolls commercial inventory. More than half of these have been upgraded to the EP standard and the follow-on Trent 700EP2, which was announced at the Farnborough air show in 2012, will be the new-build standard from 2015. The engine will be introduced with the 242-ton maximum-takeoff-weight development of the A330, and reduces fuel burn by a further 1%.

“We know what we're going to do,” says Johnston. “We are going through a series of trade studies, and rather than looking at the rotor system which is what the EP did, we are looking at the stator system and introducing better sealing around the LP turbine nozzle guide vane. We are now going through the same level of governance as a new engine. We have an audit team which looks at everything and now we've got a program. We will test an engine and prove what we are doing, although there is not a lot of technology risk because of what we are doing on the 1000/XWB.”

While the A330 market is fiercely competitive, the battle over the A380 is arguably even tougher with reliability and fuel burn under constant scrutiny. The Trent 900-powered A380 has been in service five years and, as of the Paris air show, powers 56 aircraft with six operators. Since 2012 all Trent 900s have been delivered to EP Block 1 standard. Along with elliptical leading edges, this includes tighter LP turbine tip clearance and a new hard coating for the HP compressor drum, all of which contribute to a 1% fuel burn improvement. Upgrades to boost reliability include changes to the HP and IP turbine disc and blades, IP nozzle guide vanes, seal segments, turbine case cooling, a LP location bearing package, IP turbine shaft coupling nut and a software upgrade to the electronic engine controller.

Testing of a follow-on EP2 package, aimed at up to a further 0.8% fuel burn improvement, is now underway. “The first EP2 will be delivered around mid-2014,” says Johnston who adds that the initial operator is expected to be Singapore Airlines. The EP2 configuration includes optimization of the fan blade tip clearance, tighter turbine case cooling control, better sealing of the LP turbine, aerodynamic improvements to the IP compressor and lower drag “A-frame” engine section stators between the core and fan duct. The total improvement is expected to be between 0.5-0.8%. “We'll find out when we start to run,” he adds.

Elliptical leading-edge improvements to the HP and IP compressor blades have also been bundled into retrofit upgrades for the Trent 500 and 800. The Trent 500EP+ will improve fuel burn on the A340-500/-600 by around 0.5%, building on a 1% upgrade already in service. The Trent 800EP, which was launched in mid-2012, will offer a 0.7% fuel-burn reduction. “We have customers for both,” says Johnston, who adds the first engines were installed with the new blades in April. The upgrades are introduced as part of a regular shop visit, but operators pay for the package separately. “They save much more in terms of value,” he adds. The Trent 900EP upgrades, by contrast, are provided as part of the company's TotalCare agreement with all A380 operators.