The steady rise in demand for high-thrust, big-fan engines for new wide-body commercial airplanes continues to generate massive business, as the 2015 half-year results from Rolls-Royce demonstrated. But at the same time, underlying revenue and profits can suffer as demand falters on production that is transitioning to newer, but less mature engines, and as R&D investment increases to bring forward innovation that can safeguard future market share in due course. The company’s civil aerospace order book has risen to $103.6 billion and underlying revenue in this sector was up 2% in the first half of 2015, yet profits fell.

The airframe sector of the global commercial air transport market in the size category above 200 seats is totally dominated today by just two suppliers—Airbus and Boeing—and the engine market for these wide body passenger and cargo airplanes is in the hands of just three companies—GE, Rolls-Royce, and Pratt & Whitney, in that order of sales success. Profits from sales of the largest aero engines in production reflect their high value (more than a typical regional jet) and also, increasingly, the return from care packages that can offer lifetime maintenance and repair support, providing airline operators with an attractive alternative to traditional heavy investment in MRO contracts or in-house facilities and services.

But this is a very strategic sector, and to survive, let alone thrive, the big players have to be prepared to spend considerable sums on complex and challenging R&D programs to be in a position to bring new products to market in line with changing airframe needs. Getting this right is difficult to predict many years in advance and carries with it major commercial risks, but if the application of improved designs, materials, and production methods can deliver a new engine that will significantly increase operating efficiency, while improving reliability and environmental performance, then the rewards can more than compensate for the investment.

Rolls-Royce's Trent 7000 being developed for application on the upgraded A330neo (shown is the -900) offers better all-round performance than the Trent 700 it replaces.

In reality, shareholders know that any company that just sits back and enjoys a long success run on a product without investing in its replacement will eventually have no future. Managing the cycle so that today’s revenues can produce profits while also off-setting the vital R&D expenditure that will bring forward the next generation of products is a corporate trial-by-strength challenge that only the biggest and boldest in the propulsion sector can afford to engage in. So long as they continue to be able to do this however, then they can be assured that they will remain competitive.

Looking Toward Future Technologies

No better example of such challenges is to be found than in the case of Rolls- Royce where its current profits have suffered as sales of the best-selling Trent 700, which powers the Airbus A330, have peaked and are now slowing down as more customers select its replacement, the Trent 7000, which is being developed for application on the upgraded A330neo (new engine option). This new engine is offering better all-round performance and so, understandably, customers are waiting for this latest product. At the same time, as the Trent 700 nears the later stages of its delivery life cycle the aftermarket revenues are increasing.

But this market surge for the upgraded A330 wasn’t expected just a few years ago, as Airbus intended to replace the A330 with the all-new A350, powered by the new Trent XWB engines. Although the company received a record number of orders for the new combination, you can’t buck the customer. When a substantial number of A330 operators and potential new ones told Airbus they wanted more A330s but could they please have some of the features from the Trent XWB in place of the Trent 700 (which was originally introduced in the early 1990s), Rolls-Royce responded with just that, which became the Trent 7000 and Airbus decided to launch the A330neo.

Rolls-Royce in recent years, as reported in Aerospace & Defense Technology, has been investing billions in highly innovative new technologies, materials, and production processes to safeguard and grow its market share (it wants a 50% slice of the big fanjet market) and now this is looking more and more likely to succeed as new information is revealed about the status of its new R&D programs.

New technologies in the Trent XWB family of engines are inspiring current R&D design and evaluation work as part of its strategic roadmap for future big Rolls-Royce fanjets aimed at delivery in the next decade.

In a post-Paris Air Show discussion, the company’s Chief Engineer, Future Programs, Alan Newby, outlined how the new technologies in the Trent XWB family of engines were inspiring current R&D design and evaluation work as part of its strategic roadmap for future big fanjets aimed at delivery in the next decade.

Newby said that the ongoing development work and associated test programs extended across a broad range of activities and involved many partners and specialist companies through the supply chain, as well as close cooperation with a cutting edge innovation center in academia. This work has already led to the Trent XWB and 7000 models bringing new levels of fuel efficiency and low emissions and even lower noise levels into production products, and the future engines would build on this experience and incorporate a suite of new, even more advanced technologies that will have applications across the company’s whole commercial aero engine portfolio.

The phased and very thoroughly tested nature of these programs meant that the risk element was being addressed at each stage and as the new features were integrated and evaluation proceeded, by the time the engines would be ready for the market they would already have achieved a high degree of maturity, even where they introduced game-changing improvements in performance.

The next development beyond the XWB and Trent 7000 and Trent 1000 would be the three-shaft Advance (for more detail, see April 2015 A&DT), which will introduce a new core architecture to re-define the workload split between the high- and intermediate-pressure compressors so that there will now be a twostage HP and a one-stage IP turbine. The design will exploit new technologies to drive down component weight and system complexity. The engine will feature carbon titanium (CTi) fan blades and composite fan casings and advanced high temperature technologies to deliver increased thermal efficiencies with an adaptive cooling system offering more intelligent engine controls.

A Model Future

Future Rolls-Royce engines will feature carbon titanium (CTi) fan blades and composite fan casings with other advanced high temperature technologies to deliver increased thermal efficiencies.

Under its Vision 10 roadmap, Rolls-Royce is progressing demonstration programs for validation that will aim at exploiting the latest technology advances that will have an application in the near-term, while its Vision 20 is concentrating on emerging technologies in the context of how the world, and markets, will change over a longer timescale. This twin approach is thus embracing both evolutionary improvements, Newby said, and also disruptive technologies. The company is studying development technology readiness levels that include issues relating to aspects of manufacturing, factoring in volume and quality needs, and also looking at supply chain capability at appropriate levels.

The main subject of the discussion, however, was centered on new information on the next Rolls-Royce program beyond the Advance, known as the UltraFan. This would use the same core architecture but with a new low-pressure fan system, and a power gearbox. Using variable pitch CTi wide chord fan blades will save weight over all-metallic blades and could eliminate the need for a traditional thrust reverser system, which would certainly reduce more weight and complexity.

According to Newby, the relatively slow-moving fan will be the key enabler on this engine, which will offer further improvement over the performance of the Advance design, and which translates into an efficiency improvement of 25% over the baseline Trent 700. The multistage IP turbine system will feature high aspect ratio titanium aluminide/CMC aerofoils with advanced cooling features.

Rolls-Royce has invested in a large new fan blade facility in Rotherham, U.K., where it is using the latest materials and manufacturing methodologies for its new fan blades. It is situated alongside the Advanced Manufacturing Research Center at Sheffield University, which has become a center of excellence for innovative manufacturing, materials, and processes.

The word “optimized” comes up often. “With an extra-large fan engine, weight is always going to be an issue and so [Rolls-Royce] has looked at everything that might contribute to optimizing each major element in the design,” said Newby. “UltraFan brings together a lot of new technologies in its architecture.”

One example is a slim-line low-drag nacelle, which features a composite casing with embedded electrical connectors that eases assembly and saves weight. The planning effort for the development, testing, and future production of UltraFan can be seen in the investment with the company’s program partners in Germany. Rolls- Royce has teamed with Liebherr Aerospace in this new joint venture, which will develop a gearbox that can provide a range of efficient thrust settings. Test facilities are being built at Friedrichshafen and the first test items will start to be put through their paces next year.

Advanced virtual planning is being used via a high-fidelity 3D computer model that will incorporate every component and allow high-performance computing technology to generate high levels of confidence in every design aspect well before the first engine is built. This computer-generated model extends to the whole manufacturing process, including the factory layout, so that there will be unprecedented levels of situational awareness of the status of progress at every level and workstation, for the personnel who will manage and operate the assembly lines and the associated arrivals and departures of parts and modules integrated with the supply chain. This should greatly reduce the overall costs of manufacturing and assembly, and cater for variable production flows in the future.

Using variable pitch CTi wide chord fan blades on future engines will save weight over all-metallic blades and could eliminate the need for a traditional thrust reverser system.

The use of computer modeling is also bringing tremendous advantages as the additive manufacturing revolution starts to make 3D printing of components a new reality.

“We can now make complex structures through this process and new methods of repair techniques are emerging,” said Newby. “Also, more embedded systems can be incorporated in the future, which can help save weight, time, and cost of assembly. We are still at the start of this particular revolution. The saving in time and weight (with big savings through reductions in waste materials) when producing some components by AM methods instead of casting or machining them is game-changing, with savings ranging from 30% upwards in manufacturing the same component by the new method.”

In summing up what he feels future programs may entail, Newby said, “We will see more integration between the aircraft and the engines, and maybe the distributed propulsion route, with a gas turbine generating power for electric fans distributed throughout the aircraft, but such aircraft are probably in the timeframe out beyond 2030.”

Asked about the current status of open rotor engines, he said that such powerplants could be developed through high bypass ratio ducted fans and developments following the Ultra-Fan, but initial applications might be more likely on small business aircraft rather than large commercial airliners where there were still many practical difficulties with such designs.

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