On a recent visit to Honeywell Aerospace facility in Phoenix, Arizona, the group of visiting International media (this journalist was the sole representative from India) was witness to some path-breaking engine development that Honeywell scientists and engineers are working on. These technologies are in the development phase, but are sure to revolutionise engine production in the near future.

Honeywell is working on ceramic additive manufacturing to fabricate casting cores for turbine blades and vanes in lieu of costly and complicated tooling. The company has successfully fabricated engine quality single crystal castings for the TFE731-60 1st blade which provide greatly improved efficiency and productivity. Among other research and development activity, Honeywell has developed an improved thermal barrier coating for turbine engine components with significantly lower thermal conductivity, best in class phase stability and fracture toughness and unsurpassed life. This technology significantly improves engine power and reduces fuel consumption.

Not just Honeywell, all the aero engine manufacturers are driven by the need for such advancements which will improve engine efficiency, burn less fuel, is environment-friendly and above all, reduces the cost of operation. While they are driven by the need to be competitive, they are also on path in complying with the ambitious goals for air traffic set by various bodies including the Advisory Council for Aviation Research and Innovation in Europe (ACARE). The major part of the improvements in NOx and noise emissions will have to come from the engine. The target values for reductions in aircraft engine fuel burn and in CO₂ emissions are – 20 per cent by 2020; 30 per cent by 2035 and over 40 per cent by 2050. It is happening as can be seen how over the years engines have become highly efficient. In the early 1990s, the average fuel consumption of aircraft was around six litres per 100 passenger kilometres, which now is as 2.9 litres on an Airbus A380.

Rolls-Royce Next-gen Designs

Rolls-Royce recently shared details of its next-generation of engine designs which could be ready within ten years, featuring technology innovation designed to transform performance. The company has built a technology leadership position with its Trent family of engines, the latest of which, the Trent XWB, is the world’s most efficient engine flying today. Trent engines will continue in service for decades to come with 2,500 in service and more than 2,500 on order.

Rolls-Royce is continually innovating and as part of that ongoing process, is looking to build on the success of the Trent family of engines with two new generation engine designs. The first design, Advance, will offer at least 20 per cent better fuel burn and CO₂ emissions than the first generation of Trent engines and could be ready by the end of this decade. The second, UltraFan, a geared design with a variable pitch fan system, is based on technology that could be ready for service from 2025 and will offer at least 25 per cent improvement in fuel burn and emissions against the same baseline.

Colin Smith, Rolls-Royce Director, Engineering and Technology, said, “These new designs are the result of implementing our ongoing technology programmes. They are designed to deliver what our airframe and airline customers tell us they need, even better fuel efficiency, reliability and environmental performance.”

Eric Schulz, Rolls-Royce President, Civil Large Engines, said, “As innovators, we can never stand still, even when we have the leadership position. Our horizons extend into the coming decades and we have amassed a range of new technologies to meet the needs of our customers. I am confident that our engine design strategy will ensure we power the future of global aviation.”

Both engine designs are the result of the ongoing research and development investment, of approximately £1 billion a year, which Rolls-Royce makes across its aerospace and nonaerospace business. The designs will feature architecture and technology improvements, all currently at an advanced stage of development that include new engine core architecture to deliver maximum fuel burn efficiency and low emissions, a CTi Fan System, carbon/titanium fan blades and a composite casing that will reduce weight by up to 1,500 lb per aircraft, the equivalent of carrying seven more passengers at no cost; advanced ceramic matrix composites—heat resistant components that operate more effectively in high turbine temperatures and a geared design, called UltraFan, which will deliver efficient power for high-thrust, high-bypass ratio engines of the future.

While Rolls-Royce currently focuses on development of the Trent XWB for the Airbus A350 and the next version of Trent 1000TEN for the Boeing 786, the engine maker has unveiled its strategic roadmap for a new generation of turbofans for entry into service from 2020. The ambitious plan centres on a twophase evolution of the three-shaft architecture that is designed to position Rolls for new applications in the wide-body market. Because the technology is scalable, Rolls believes the strategy could also provide a launch platform for new medium-thrust engines, possibly allowing it to re-enter the narrow-body market ceded to Pratt & Whitney with its withdrawal from International Aero Engines in 2013. The road map also sees Rolls introducing composites on a wider scale in new areas such as fan blades and casings and in its second phase, embraces geared turbofan technology for the first time. In the longer term, the plan also keeps the door ajar for potential open-rotor engine derivatives.

In addition, Rolls-Royce has developed and tested technologies to support the Open Rotor engine concept and is positioned to mature them should there be clear market demand for such a product.

GEnx Turbofan

The GEnx is GE’s next-generation turbofan and will be the workhorse engine of the 21st century for medium-capacity, long-range aircraft. Designed around customers’ needs, the GEnx represents a giant leap forward in propulsion technology. The engine will use the latest generation materials and design processes to reduce weight, improve performance and lower maintenance. The GEnx is part of GE’s ‘ecoimagination’ product portfolio—GE’s business strategy to develop new, cost-effective technologies that enhance customers’ environmental and operating performance. The GEnx will deliver 15 per cent better specific fuel consumption which translates to 15 per cent less CO₂ than the engines it replaces, helping operators save whenever they fly. Its innovative twin-annular pre-swirl (TAPS) combustor will dramatically reduce NOx gases as much as 56 per cent below today’s regulatory limits. Additionally, the GEnx’s emissions for other regulated gases will be as much as 94.5 per cent below current regulatory limits, ensuring clean compliance for years to come.

Based on the ratio of decibels to pounds of thrust, the GEnx will be the quietest, most passenger-friendly commercial engine ever produced due to the large, more efficient fan blades that operate at a lower tip speed, resulting in about 30 per cent lower noise levels. It will be the world’s first commercial jet engine with both a front fan case and fan blades made of carbon fibre composites, which are both durable and low maintenance. This technology reliability has been validated over more than 15 years and 22 million flight hours on the GE-90.

All of these improvements are thanks to the incorporation of advanced and proven technologies from other engine families and ongoing R&D programmes, such as lightweight, durable composite materials and specialised coatings, an innovative, clean-burning combustor and a fan module that’s virtually maintenance free. It is a low-risk, high-value solution to the challenges customers face every day. It is the GEnx.

Pratt & Whitney Higher Thrust PurePower Engine

Pratt & Whitney in May launched the newest addition to the PurePower engine family, the PW1135G-JM engine, a 35,000 lb thrust class engine for the Airbus A321neo aircraft. The engine’s higher thrust rating makes it the most powerful engine on the A321neo allowing A321neo operators fitted with Geared Turbofan engine technology, to fly routes of greater distance while carrying more passengers or larger payloads when operating out of high-altitude airports. “At Pratt & Whitney, we’re always working to stay one step ahead with our technology while providing our customers value. The PurePower PW1135G-JM engine is yet another example of this approach,” said David Brantner, President, Pratt & Whitney Commercial Engines. “With the PW1135G-JM engine, we offer incremental value by opening up new routes without compromising fuel burn, emissions and environmental performance.”

The higher thrust offered by the PW1135G-JM engine allows an A321neo operator to benefit from increased range when operating out of high altitude airports, such as Mexico City and Bogota. Compared with an A320ceo without Sharklets, the A320neo powered by PW1100G-JM engine technology will provide customers with up to a 15 per cent reduction in fuel-burn with a corresponding reduction in CO₂ emissions. The PW1100G-JM engine also provides up to 75 per cent reduction in the A320neo noise footprint, which is also environmentally-friendly and allows longer hours of operation at airports that operate under curfew.

To date the PurePower engine family has completed more than 9,000 hours of testing, including more than 1,200 hours of flight test hours. Pratt & Whitney has more than 5,500 Pure-Power engine orders and commitments, including options.

LEAP Forward

LEAP is a new-generation engine designed and developed by CFM International, the 50:50 joint venture company of Snecma (Safran) and General Electric, through a very technologically ambitious development programme. The new LEAP engine will incorporate a number of innovative technologies developed through the LEAP research & technology programme. It is mainly designed to power the next-generation of single-aisle commercial jets.

LEAP features a host of advanced technologies to help reduce its fuel consumption by 15 per cent, NOx emissions by 50 per cent and noise to 15 decibels. There will be fewer fan blades (18 against 24 to 36 in CFM56 engines) and the engines will be lighter, since they are made of composite materials using a proprietary woven 3D Resin Transfer Molding (RTM) process. Use of new composites on fan blades and other components would reduce the weight of the aircraft by about 450 kg.

In December 2009, the Commercial Aircraft Corporation of China (Comac ) selected LEAP as the only Western propulsion system for its new, single-aisle commercial jet, the C-919. Designated LEAP-1C, this engine is the first member of the LEAP family slated for certification in 2015. CFM International will also supply the nacelle and thrust reverser, developed in partnership with Nexcelle, a 50:50 joint venture of Middle River Aircraft Systems (GE) and Aircelle (Safran).

A year later, in December 2010, Airbus also chose Safran’s new engine, this time the LEAP-1A version, as one of the powerplants to be offered on its new A320neo. This new aircraft could enter service in mid-2016. Boeing subsequently selected the new engine, the LEAP-1B version, as the exclusive power-plant on its new 737 MAX.

Indeed, there is frenetic research going on in engine development by all the manufacturers. This is imperative to stay in business as well as to be responsible companies.