Rolls-Royce And Airbus Near Accord Over A380neo

By: Guy Norris published in aviationweek.com, Dec 15, 2014

Airbus is accelerating its studies of an upgraded A380 and, after talks held last month with engine makers in Toulouse, appears to be closing on an initial agreement with Rolls-Royce.

The engine manufacturer is strongly supporting plans for both the A380neo and the potential A380-900 stretch. According to industry sources, Rolls-Royce is discussing a variety of all-new engine options ranging from derivatives of the A350’s XWB-84/97 to the future Advance project unveiled earlier this year. Until recently it was widely believed Rolls-Royce may be in pole position for a possible slot on the upgraded A380 because of its victory on the A330neo with the Trent 7000, a similarly-rated engine as the current unit. This engine is due to debut on the Airbus twin in late 2017 and is derived from the ‘TEN’ version of the Trent 1000, now under final development for the Boeing 787. However sources say the proposed A380neo project will require more power than the Trent 7000 which is rated at between 68,000 lb. and 72,000 lb. for the A330-800neo and -900neo.

Although Rolls-Royce declines to comment on the A380 situation, the transition to a potentially greater thrust engine could provide for higher gross weights or presage the long-anticipated development of the A380-900 stretch. The development cost for the baseline A380neo is estimated at around $2.5 billion, primarily because of the structural revisions required for the wing, and is expected to take around four years based on previous experiences such as the A340-500/600.

The push to launch the A380neo is backed by Emirates Airline, the largest single customer for the model. Emirates CEO Tim Clark, who says the carrier could “definitely” order as many as 70 of the re-engined variants if launched, is also poised to announce the engine selection for 50 standard A380-800s ordered at the 2013 Dubai Air Show. Although Emirates operates the world’s largest fleet of GP7200-powered A380s, Rolls-Royce is bidding aggressively for the supplemental fleet order and appears to be growing in confidence that it can break the GP7200 stranglehold on Emirates.

The U.K. manufacturer currently competes for the A380 with the Trent 900 against the joint General Electric-Pratt & Whitney Engine Alliance GP7200, but is eager to build on its relationship with Airbus where it has exclusive engine deals on the new A350 family and recently launched Trent 7000-powered A330neo. The parent companies of the GP7200, on the other hand, cite an uncertain business case for the upgraded A380 and appear reluctant to make the substantial investment such a venture would require, despite holding more than 50% of the existing market.

The Engine Alliance has outlined upgrade plans which could produce near term fuel savings of 0.5% to 1%, but still well below the 10% to 12% thought to have been outlined by the Airbus requirement. Even more comprehensive upgrades for the GP7200, including a larger fan and an additional low pressure turbine stage, would gain only around 5% and be “cost prohibitive” in the absence of a compelling business case says the Engine Alliance. The difference between an incremental upgrade and an all-new engine therefore represents a financial gulf across which neither GE nor Pratt appears willing to step.

Speaking to Aviation Week, GE Aviation president David Joyce says “If you ask me if the business case closes for us to drop the GP (GP7200) and put a new engine up under the A380, I would tell you we can’t make that business case close. We just can’t, there’s just not enough incremental sales around the world that would make that case close.” GE is currently developing the Leap narrowbody engine with Snecma and is finalizing the design of the GE9X for Boeing’s 777X twinjet. “Today if someone came to me with a proposal to put a brand new engine underneath that wing — I just don’t see that as being a priority for us,” adds Joyce.

Pratt, like GE, is also deeply mired in the development of the PW1000G geared turbofan family, and says it can ill-afford an additional commitment. United Technologies CEO Greg Hayes says Pratt is unlikely to support the development of a new widebody engine for some time. Commenting at an investor conference Hayes says the company “cannot continue to afford to invest at these levels.”

Airlines satisfied with 787 engines despite efficiency miss

By: Stephen Trimble published in flightglobal.com, Nov 17 2014

If one of today’s market fashions becomes permanent, the Boeing 787 could be the last commercial widebody aircraft that offers buyers a choice of engines from competing suppliers – in this case the GE Aviation GEnx-1B or the Rolls-Royce Trent 1000.

This increasingly rare engine competition has delivered two propulsion systems with reliability levels well above the average at the aircraft level.

At the same time, it has so far failed to produce a turbofan engine designed by either competitor that meets Boeing’s original promise of a 10% reduction in specific fuel consumption.

Additionally, competitive pressures have not provided airline customers with immunity from brief operational crises with both engines, in one case an operational restriction that still continues.

Both engines boast despatch reliability levels above 99%, the benchmark Boeing is still seeking to claim for the aircraft as a whole.

“The engines are operating flawlessly,” says Zemene Nega, vice-president of maintenance, repair and overhaul for Ethiopian Airlines, a GEnx-1B customer.

It has not always been so. In July 2012, All Nippon Airways, a Trent 1000 customer, grounded five 787-8s after Boeing informed it of a potential problem in the gearbox. Crown gears had corroded faster than expected in endurance tests on the ground, causing damage to the engine. R-R traced the problem to a manufacturing process change by gearbox supplier Hamilton Sundstrand. It was corrected within weeks.

The GEnx-1B became the focus of the next engine crisis. A decision by GE Aviation to adopt a new lead-free coating on the fan mid-shaft backfired with explosive results. The coating caused the component to corrode faster in humid climates. In late July 2012, a GEnx-1B on board a newly assembled Air India 787-8 sustained a contained failure. GE reverted to a previous lead-based coating, and the problem disappeared.

Rolls-Royce‘s next move is to deliver the Trent 1000-TEN upgrade in mid-2016

Rolls-Royce

A longer-term problem for GE Aviation is a relatively new phenomenon called ice-crystal icing. Liquid water is not present above about 22,000ft, so airframe icing is never a concern at cruise altitudes for a turbofan-powered widebody aircraft.

However, meteorologists have recently discovered the presence of ice crystals at even higher altitudes, especially in tropic latitudes. In massive storm concentrations stretching 100km (62mi) across, convection forces can carry ice crystals the size of a grain of flour to cruising altitudes above 30,000ft. The crystals bounce off an aircraft’s skin, but can be ingested into an engine. It is believed that crystals land on a warm blade and begin to melt, which attracts other crystals to stick to the blade. Eventually, enough ice develops on the blade to cause damage downstream when it sheds.

The phenomenon is particularly acute on the GEnx engine. On its predecessor, the CF6, the ice build-up would most often shed as the aircraft descended. The GEnx experiences the ice shedding problem at cruise altitude, leading to in-flight engine shutdowns. As a result, the US Federal Aviation Administration issued an airworthiness directive last year requiring airlines to steer 787s at least 50mi wide of major storm concentrations.

For some airlines, the restriction is an annoyance but not a network issue. Japan Air Lines, however, has pulled the 787 off three routes originating in Tokyo: Bangkok, Delhi and Singapore.

By contrast, the Trent 1000 engine faces no such operational restriction, says R-R project director Gary Moore. Fortuitously, the three-spool architecture of the Trent engine family happens to be less prone to ice crystal build-up inside the core. The intermediate compressor section, which is absent in the GEnx design, rotates at a higher speed, making it more difficult for dangerous quantities of ice to build up on the blades.

“We don’t have this problem,” Moore says. “It is just a very clear difference in the two engines.”

Another clear difference between the engines is the order split. So far, 787 customers have chosen the GEnx-1B over the Trent 1000 by a nearly two-to-one margin, with 17% of the order backlog still unspecified.

R-R places a couple of caveats on the GEnx-1B’s strong start. First, not all airline decisions have been the result of a competition. When given the chance to compete, the Trent 1000 has claimed nearly half of the orders, Moore says. Moreover, the Trent 1000 is starting to gain some momentum. In the last 19 engine selections, the Trent 1000 has won orders 11 times, he says.

R-R’s next move is to deliver the Trent 1000-TEN upgrade in mid-2016. GE has acknowledged that the GEnx-1B misses, by 1-2%, Boeing’s original specification for reducing specific fuel consumption. The Trent 1000-TEN – packed with technological improvements inherited from the Trent XWB – is still aimed at achieving the 787’s original fuel-burn target.

“We’re targeting the original spec that was put upon the airplane,” Moore says. “You don’t spend this level of investment to think we’re not going to get there. We’re going to get there.”

Rolls-Royce harvests a decade of research for new engine projects

By: MURDO MORRISON published in flightglobal.com, Oct 1 2014

As Rolls-Royce prepares to build and begin testing next year its seventh member of the Trent family – the 7000 for the Airbus A330neo – it is harvesting the fruits of a decade’s worth of research and development projects into two studies that could form the basis for a new generation of widebody – and even possibly narrowbody – engines in the 2020s.

The UK propulsion specialist wants to develop technology and products that will secure a 50% share of the twin-aisle market, as well as – perhaps more ambitiously – help it break back into the growing single-aisle sector, vacated when it abandoned the International Aero Engines consortium in 2012, just when a host of new narrowbody programmes were arriving on the market.

The company earlier this year revealed its Advance and UltraFan designs. Although both are far from being formal programmes, they are based on the three-shaft structure of the successful widebody Trent family, in particular the Airbus A350’s Trent XWB. R-R says they could, in theory, be ready to enter service as production engines as early as 2020 and 2025, respectively.

R-R says Advance and UltraFan are about highlighting its progress in a range of technologies, from composite fans to lower-emissions combustion systems. The company’s timescale for bringing these to market, however, means the engine studies are more than simply “what-might-be” concepts. It has already proved, or is currently testing, many of the engines’ novel elements.

The advance’s carbon/titanium fan system has been tested on a Trent 1000 at the Stennis centre

Rolls-Royce

Advance and UltraFan are not just Trents with tweaks, stresses Alan Newby, chief engineer, future programmes and technology. Although they rely on the same three-shaft architecture, the first of the two engines, Advance, will have a new core – with a larger high-pressure compressor and smaller intermediate compressor – as well as a composite fan and casing.

Other changes include an adaptive cooling system, a lower NOx combustor, “dynamic sealing” to minimise leakage and a wider use of ceramic-matrix composites. “Advance is the next generation in three-shaft engines and brings together a lot of the technologies that we’ve been working on for the past 10 years. There are a lot of differences. The HP and IP compressors are very different,” he says.

There is a clear commercial goal too. “We are getting the technology bricks in place, and when we get the call to develop [Advance] for an aircraft programme, we will,” adds Newby. “We won’t launch a programme until we have a requirement, but we think we will have de-risked all the technologies by 2015 or 2016 and be ready with a new application from 2020 onwards.”

The test or “slave” engine for many of the new core technologies is a Trent XWB, with its core removed and replaced by the trial HP and IP system. “It’s a good platform for testing. We have quite a big project team up and running on it,” says Newby. R-R has started machining components for the engine and other elements have been ordered from the supply chain.

Although the company has no plans as yet to fly the adapted Trent XWB independently, it will undertake ground tests next year. Separately, a carbon/titanium fan system, which will be used on both Advance and UltraFan, has just completed a phase of testing – on a Trent 1000 engine – at the company’s outdoor jet engine test facility at the John C Stennis Space Center in Mississippi.

While R-R plans to test elements of its Advance engine separately, it intends to build a whole engine demonstrator for the UltraFan, with a vision of it taking to the air on a flying testbed by the end of the decade. “Given the amount of changes, we would need to verify it in flight,” says Newby. “Four or five years before entry into service is when you’d want to be maturing the technologies.”

Several engines are dedicated to research

Rolls-Royce

These technologies include a variable pitch fan, with gearbox, and a high-speed IP turbine, as well as possible adaptations to the core. “UltraFan takes the core configuration we will have developed for Advance and adds a lower-speed fan,” explains Newby. “This turns at a relatively low speed, so it makes sense to add a gearbox.”

Although UltraFan retains the Trent’s three-shaft compression system, the enhanced IP turbine drives the fan via a power gearbox, allowing the LP turbine to be eliminated. The gearbox is “critical technology”, says Newby. “We have experience through our work on the JSF [Lockheed Martin F-35 Joint Strike Fighter] and elsewhere on the military side. We are not starting from scratch.”

The engine manufacturer has already allocated more than a dozen engines to the various technology projects that have led to Advance and UltraFan. Many of these have been supported with research and development funding from the EU and R-R’s “home” governments: the UK, USA and Germany.

Its ALPS study, intended to come up with a lightweight LP system, has used three Trent 1000s. The first phase of engine testing was completed in 2013 and the second has just finished at Stennis. A third Trent 1000, fitted with the composite fan, has been shipped to Tucson, Arizona, for flight testing on a Boeing 747 by the end of the year.

A second project, EFE, running since 2010, focuses on “hot end technologies” and also uses the Trent 1000. Testing on a fourth engine has just ended at R-R’s Bristol facility. A final study, ALECSYS, is about developing a “robust lean-burn combustion system” and involves flight testing two Trent 1000s converted with a lean-burn combustor in 2015 and 2016.

R-R claims that the bundle of technologies on Advance and UltraFan could improve efficiency by 20% and 25% respectively, compared with the first Trent, the Trent 700. Newby adds that the technology is scalable and could cover a range of thrusts from 30,000lb (134kN) to more than 100,000lb, a much broader band than the current family’s 53,000-95,000lb range.

However, the company is quick to point out that this does not offer a direct clue to how it might re-enter the single-aisle market in the next decade. “Scaling down is possible, and in theory these technologies could form the basis of a new narrowbody engine,” says Newby. “But this is not necessarily the route we will take.”

Rolls-Royce makes progress with Trent 7000

By: MURDO MORRISON published in flightglobal.com, Oct 2 2014

Although understandably coy before Airbus’s Farnborough announcement that it was launching the A330neo, Rolls-Royce was by July quite far along the path of finalising the design for the Trent 7000, the 72,000lb (320kN) thrust engine that will exclusively power the re-engined widebody. Rolls-Royce already has a more than 50% share of engines on in-service A330s, with its original Trent 700.

The 7000 is based on the latest iteration of the Trent 1000 for the Boeing 787, the Trent 1000-TEN, and includes features such as weight-saving blisks in the compressors and a system that integrates engine dressings into composite raft-like structures. The first engine will be built and ground tested next year. Flight test engines will follow in 2016 ahead of the first actual flight test in 2017, with entry into service slated for late 2017.

Other changes compared with the original Trent 700 for the Airbus A330 – launched in March 1995 – include a 2.84m (112in) fan, rather than a 97in one that helps double the bypass ratio to 10 and improve specific fuel consumption by 10%. “For us, basing it on the TEN makes it a very low-risk programme,” says Peter Johnston, head of customer marketing.

The bigger fan means the engine and Aircelle-designed nacelle have to be moved forwards and upwards, compared with the Airbus A330’s Trent 700, to retain the same level of ground clearance and avoid “sucking in too much dirt”, says Johnston. The big architectual difference with the TEN is a new external gearbox because Airbus’s system is different to Boeing’s.

The engine manufacturer has a full dedicated project team in place for the 7000, which can pull in expertise from both the Ten and the Trent 700 teams, he says. The engine gives R-R itself a foot in two camps too, with a competitive position – against General Electric’s GEnx – on the Boeing 787, as well as an exclusive arrangement on the Dreamliner’s new direct competitor.

Rolls-Royce Details Advance And UltraFan Test Plan

By Guy Norris, published in Aviation Week & Space Technology, Aug 25, 2014

Earlier this year Rolls-Royce took the unusual step of publicly laying out its strategic vision for developing a new series of large turbofans for the next decade and beyond. Now the company is beginning to detail the first steps it will take to turn this vision into reality.

The launch of its next-generation road map comes at a good time for the company. Buoyed by growing volumes of business in the widebody airliner market with its three-shaft Trent engine family, Rolls is in the midst of its biggest production ramp-up ever to support expanding fleets of Trent 1000-powered Boeing 787s and XWB-powered AirbusA350s. At the same time, it is developing the Trent variants for the later derivatives of both these airliners, as well as beginning work on the Trent 7000 for the newly launchedA330neo.

First steps toward Advance are underway with ground and flight tests of a composite fan under the Advanced Low-Pressure System program. Credit: Mark Wagner/aviation-images.com

Banking on the notion espoused by President John F. Kennedy that “the time to repair the roof is when the Sun is shining,” Rolls is acting now to ensure its competitiveness for the next round of airliner developments from the end of the decade and beyond. Ric Parker, director of research and technology at Rolls, says that thanks to the A350 and 787 engine programs, “we are in an amazing position today.” At the American Institute of Aeronautics and Astronautics Joint Propulsion Conference in Cleveland in late July, Parker also noted that the company’s strategy closely monitors the point “where evolution gives up and revolution takes over.” For the near term, the plan remains focused on the former, and the next steps will therefore be based on two more evolutions of the well-proven three-shaft heritage. “At Rolls-Royce we say, ‘invent once and use many times,’” adds Parker.

Rolls-Royce’s fundamental product plan, as first unveiled in February (AW&ST March 3, p. 20), is a two-phase evolution from today’s Trent XWB. The first engine, the Advance, is aimed at entry into service around 2020 and will have a bypass ratio in excess of 11:1, overall pressure ratio of more than 60:1 and fuel-burn level at least 20% better than the current Trent 700. The second, more ambitious follow-on engine is called the UltraFan, which Rolls first revealed in concept form in early 2012 as part of NASA’s Environmentally Responsible Aviation (ERA) study with Lockheed Martin. The engine could be ready for service in 2025 and is targeted at fuel-burn at least 25% better than the Trent 700. UltraFan drives a variable-pitch fan through a gear system and is outlined with a 15:1 bypass ratio and overall pressure ratio of 70:1.

Step 1 of the evolution involves fundamentally changing the traditional architecture of the Trent core to off-load the work performed by the intermediate-pressure (IP) spool and split it more evenly with the high-pressure (HP) system. To understand the significance of this, it is useful to note the basic architectural differences between the Trent family and the competing two-shaft designs produced by General Electric and Pratt & Whitney. Unlike these two-shaft engines, in which the fan and low-pressure (LP) compressor are driven by the LP turbine, the fan alone is driven by the LP turbine in the Trent. In place of the conventional LP compressor, the three-shaft design has an IP compressor which is driven by an IP turbine. Both two- and three-shaft engines have similar high-pressure spools, though there are fewer stages in the three-shaft compressor and turbine.

In previous evolutions of the Trent, Rolls has grown engine capability by expanding the work done by the IP compressor and turbine. “As we grew the Trent family IP compressor, we grew the pressure ratio and gradually supercharged the engine, always keeping the high-pressure spool very similar,” says Alan Newby, Rolls commercial engines advanced projects chief engineer. “The big change from the core point of view is that the Advance reverses that, so we will put more on the high-pressure spool,” he adds. The new Rolls engine will have a relatively larger high-pressure compressor with up to 10 stages (compared to six on the Trent XWB) and a greater pressure ratio, and it will be driven by a two-stage turbine against the single-stage used today. At the same time, the IP compressor will shrink from the eight stages of today’s XWB to around four, while the IP turbine count will be cut to one from two stages.

The new configuration “provides a very lightly loaded high-pressure spool, which gives good efficiency and, more importantly, significant commonality with the follow-on core of the UltraFan,” says Newby. “So we are laying down an architecture which we think is enabling the future.” In addition, for the first time on any Rolls engine, Advance will have a lighter composite-titanium fan, composite fan casing and lighter LP turbine system.

With a bypass ratio of more than 11:1, Advance will be distinguished by a larger fan and longer high-pressure compressor. Credit: Rolls-royce

Beyond Advance, the next big architectural change is the inclusion of a gear system to drive what Rolls believes will be a new generation of larger, higher-bypass-ratio fans, as well as the introduction of variable pitch fan blades and complete elimination of the LP turbine. The move effectively means the engine is no longer a true three-shaft design but rather a “two-and-a-half” configuration, notes Newby. However, Parker adds, “Even with three shafts, we still haven’t reached the tipping point where the weight and complexity of the gearbox outweighs the weight and complexity of lower-speed, lower-efficiency components. That’s primarily because we don’t have a low-speed booster on the fan shaft. Instead, we have an IP compressor that finds its own speed.”

Besides major architectural changes, both Advance and UltraFan will see the wholescale introduction of new technologies. In some cases these will be key enablers to the new configuration and in others they will help augment overall performance. “Arguably, the Advance is mainly about the core, though we are introducing the lightweight low-pressure system, so it is a bit of improving propulsive efficiency and lot about improving thermal efficiency,” Newby says. The lightweight fan and casing will have “a novel system of embedding harnesses and pipes in a composite ‘raft’ attached to the casing,” he adds. Other technologies will include a more advanced low-emissions combustor, lightweight compressor and turbine blade designs, improved blade cooling, dynamic sealing and adaptive cooling systems to optimize bleed off-take cycles. It will also feature new hybrid ceramic bearings to support the lighter core in positions farther aft in cooler, more benign locations, away from hotter locations faced by current bearings. 

Key technologies for UltraFan will build on the Advance developments in some cases and in others—such as the power gearbox, variable pitch blades and variable area nozzle—will be all-new. UltraFan will also have a new form of fully integrated, slim-line nacelle design. As the fan system is designed to vary pitch in all phases of flight, including landing, the nacelle will not include a thrust reverser. UltraFan will have a multi-stage IP turbine, the blades of which will be longer than any previous design. To reduce weight, titanium aluminide will be used for rotating parts and ceramic matrix composites (CMC) for static parts such as nozzles. 

Some potential technology elements “may be longer-term and may not be in the UltraFan when we take it to market,” says Newby, citing cooled cooling air and “blings” (bladed rings) as examples. An actively controlled cooled cooling-air system holds the potential to enable higher pressure cycles and turbine exit temperatures because it not only removes bleed air at a later stage, but it reinjects significantly cooler air back into the turbine blades, stator vanes, rotor disk and possibly liners. The system works by taking bleed air from the back of the compressor, passing it through a heat exchanger system linked to the bypass duct, and routing it into the turbine section. Testing of basic cooled cooling-air systems has been undertaken as part of the European Newac program.

Blings are “the next evolution from blisks [bladed disks] today and this takes it further,” Newby says. The bling eliminates the need for a deeper ring by having a very strong, potentially reinforced metal-matrix ring with integral blades formed on the outside.

Validation of the composite fan for Advance is underway as part of the ALPS (Advanced Low-Pressure System) program. The new fan set has been mounted on a pair of Trent 1000 engines in a straight swap for the original hollow titanium fan. Following initial sea-level testing here, one ALPS test engine has been shipped to Rolls-Royce’s site at Stennis Space Center, Mississippi, for crosswind evaluation. A second engine is being readied for flight tests later this quarter on the company Boeing 747-200 flying testbed in Tucson, Arizona. “That’s really a final check to make sure there is nothing in terms of flight loads that we haven’t spotted in sea-level testing. We wanted to do the Stennis testing first to make sure we understand its behavior,” Newby says.

The projected weight savings of 750 lb. per engine from adopting the new material is “well worth having,” he adds. Although GE has been using composite fans on its large engines since the 1990s, Rolls said its hollow titanium blades have remained competitive. However, with increasing fan diameters, “the time is right because the manufacturing technology allows us to get the thickness [of a composite blade] right down,” says Newby.

More substantial tests of the Advance core technology at full engine scale are also planned using a Trent XWB donor engine. “We will take the HP and IP spool out of an XWB and replace it with an Advance core architecture,” Newby says. He notes that the “Stage 1” exit from concept definition is finished and design freeze is the next step. “We have already got the disk forgings in, and we are starting to machine those. We are looking at different supply chain options to get bits in quickly, and our plan is to run the first build by the end of next year and run a further build [for endurance testing] in 2016,” he adds. “A team has been created and it has got that buzz about it like a new project. It is quite exciting.”

The new core section will incorporate a four-stage IP compressor and 10-stage HP compressor for the testing, though Newby cautions that this “may or may not be the final production configuration,” adding: “It’s not just about the aerodynamics; it’s about how you bring it together as a system. It is those things we want to check as well as the basic aerodynamics.” The only stage counts that are guaranteed to carry through to the production standard will be the test unit’s single-stage IP and two-stage HP turbines.

The higher pressure ratios planned for Advance and UltraFan mean higher operating temperatures and increased generation of nitrous oxides. Several key technologies for coping with these—and to reduce fuel burn and emissions—will be validated during continuing runs of Rolls’s long-running Environmentally Friendly Engine (EFE) test unit. First run in 2010, the fourth build of the Trent 1000-based EFE recently completed a new series of evaluations of high-temperature-capable advanced turbine materials and a lean-burn combustor design. EFE was used to test CMC high-pressure turbine blade tracks in 2013 and more recently evaluated CMC shroud segments. Testing will continue through 2015, Newby says.

Trials of a robust lean-burn combustion system have “gone really well,” says Newby. “We have done rig and core engine testing and will run another Trent 1000 with a new combustion module. We’ve done the chemistry in the rigs and we know it works, so this is about putting into a systems environment to see how it behaves on relight, altitude relight, pull-away and when you put water down it. Again like ALPS, this Advanced Lean Combustion System (Alecsys) and EFE are all full-scale Trent 1000s, and Advance will be XWB.” Together with earlier work conducted in Germany under the European Clean Sky 1 research program and Alecsys, “we know this gives us good margin to the [emission regulations] CAEP 6 and 8, and gives us confidence we can meet targets even with more aggressive cycles,” Newby says. “So this allows us to grow these cycles and improve emissions which tend to go in the opposite direction.” Following ground tests, Rolls plans to flight-test the new combustor in 2015 on the company’s 747 flying testbed.

In readiness for UltraFan, Rolls is building a €65 million ($87 million) research and development facility in Dahlewitz, Germany, for testing power gearboxes. “This is a big program,” says Newby. “It will take the Advance core, which we are laying down through the XWB, and wrap a new low-pressure system around it. This will be one of the main parts of the Clean Sky 2 program and is partially funded through both U.K. and German national programs,” he adds. Although Rolls acknowledges the UltraFan gear will be a form of planetary device, it is reluctant to divulge more details. “We have a clear idea of what the baseline is, and we think we know what the right answer is; we just have to validate it. The gear ratio will be around 3:1, if not probably a bit more.” The rig will be adaptable to various engine sizes and capable of testing gear units and associated oil systems at various angles and attitudes. Power gearbox testing is scheduled to run through the end of 2015, with component testing running beyond that.