Engines that Care

Air transport’s contribution to climate change represents only two per cent of human-induced CO₂ emissions and 12 per cent of all transport sources. Aircraft flights produce 628 million tonnes of CO₂ yearly. Nevertheless, efforts are on globally to reduce the environmental impact and engine design is the key to the ongoing efforts. The Advisory Council for Aeronautical Research in Europe (ACARE) has set targets for 2020 that include reduction in fuel consumption and CO₂ emissions by 50 per cent er passenger kilometre, reduction in NOx emissions by 80 per cent and reduction in perceived noise by 50 per cent.

It is already happening as can be seen how engines have become highly efficient over the years. 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. However, ACARE has identified the main contributors to achieving the above targets. The predicted contributions to the 50 per cent CO₂ emissions reduction target are: efficient aircraft: 20-25 per cent; efficient engines: 15-20 per cent; and improved air traffic management: 5-10 per cent. Aero engine manufacturers are driven by the need for advancements that will improve engine efficiency, burn less fuel, are environment-friendly and above all, reduce the cost of operation.

Honeywell Enhancing Engine Performance

Honeywell Aerospace is developing 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 singlecrystal 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.

Rolls-Royce Next-gen Designs

Rolls-Royce nextgeneration of engine designs may be transformed to engines 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. 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.

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 non-aerospace 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, highbypass ratio engines of the future.

GE’s Latest Technologies Power its Engines

In more than a century of building engines and powering flight, GE Aviation has never stopped innovating. All those years of research, testing and development will come together in the all-new GE9X engine to power the new Boeing 777X airplane. This purposed-designed power plant will build on the proven architecture of GE’s twin-aisle engine family while incorporating the latest technologies and materials.

The GE9X will be the most fuel-efficient engine GE has ever produced on a per-pounds-ofthrust basis, designed to achieve significant fuel burn savings over its predecessor, including: 10 per cent better Specific Fuel Consumption (SFC) than the GE90-115B-powered 777-300ER and five per cent better SFC than any other twin-aisle engine in 2020.

While the GE9X will reuse proven features and architecture from the GE engine portfolio, every material, coating and aero feature/geometry is being perfected and evolved for this particular engine. The technology highlights include highpressure turbine that features new materials and cooling technologies along with updated aerodynamics and TAPS III combustor accommodating higher inlet conditions to meet new emissions requirements.

Also, GE has a record-setting 11-stage compressor that will help make the power plant the most fuel-efficient engine ever from the company. It features a 27:1 compressor pressure ratio contributing to an overall engine pressure ratio of 60:1 – the highest pressure ratios ever produced in the entire history of aviation.

Pratt & Whitney Working on 600 ‘Green Projects’

Pratt & Whitney Canada is a leader in the green evolution in aerospace with a new generation of technologies and environmental stewardship across all facets of its business, outperforming the most stringent the International Civil Aviation Organisation (ICAO) standards. Today it is working on some 600 ‘green’ projects in collaboration with 20 universities across the country.

Pratt & Whitney Canada’s PW307 is the greenest engine in its market and shows an improvement of more than 30 per cent in emissions relative to ICAO standards. Its TALON 2 combustor technology also meets Zurich 5 requirements for no surcharges. Another great example is Pratt & Whitney Canada’s new Pure- Power PW800. This engine will show an improvement of up to 50 per cent in NOx emissions relative to ICAO standards, as well as an improvement of 35 per cent in carbon monoxide emissions.

In the longer term, new technologies are being developed by Pratt & Whitney Canada to reduce NOx down to 80 per cent reduction level, benefiting from further combustion and engine performance improvements.

New Materials in LEAP

Carbon fibre is revolutionising the aviation industry and CFM is revolutionising carbon fibre or at least one of its applications. LEAP fan blades are manufactured from carbon fibre composites using a propriety process that weaves the blades in three dimensions on a loom into their final shape. They are then injected with resin and baked in an autoclave. Finally, a titanium leading edge is added for durability.

The result is a lightweight, highly durable, virtually maintenance-free fan. The fan, combined with the composite fan case, reduces aircraft weight by 1,000 lbs compared to the same size fan manufactured using all-metal materials. This lower weight, along with state-of-the-art blade aerodynamic design, contributes nearly half of the 15 per cent fuel efficiency improvement the LEAP engine will provide.

Two families of engines have contributed significantly to the design of the LEAP engine, the CFM56 and the GE90/GEnx series of engines. The GE90/GEnx contributed the high-efficiency core architecture to minimise fuel consumption, while the CFM56 legacy drove reliability and maintenance cost design practices. At entry into service in 2017, it is estimated that the GE90/GEnx architecture will have generated 80 million flight hours of revenue service, while the CFM56 family will have over 700 million flight hours of experience. The LEAP engine family offers proven, material advantages over any other engine, with 5,50,000 hours of proven experience with 99.98 per cent reliability, and 22,000 engines delivered on-time and on-spec.

The CFM LEAP pedigree ensures with confidence the ability to deliver a 15 per cent improvement in fuel efficiency, as compared to the CFM56-7BE, while maintaining the same level of dispatch reliability and life-cycle maintenance costs as the CFM56-7BE. With its simple architecture and $2 billion annual investment in technology, the LEAP engine family offers the lowest cost and highest revenuegenerating ability, saving an estimated nearly $3 million per plane.

A number of factors are driving engine manufacturers to invest heavily in research and development, foremost being the concern for environment. Also there are issues of cost of operations, improved efficiencies and the like which are making companies lot more responsible towards environment.