Europe spends €1.6 billion to create cleaner aircraft

Paul Boughton
Environmentalists are quick to criticise the air transport industry, saying that aircraft emissions of CO2 (carbon dioxide) are substantial and damaging to the environment. In reply, aircraft manufacturers point out that emissions from aircraft only account for approximately two per cent of global CO2 emissions, and that aircraft CO2 emissions today are 70 per cent lower than they were when the jet engine was introduced four decades ago. Nevertheless, the industry is also acutely aware of the predicted growth in air travel and the high price of fuel, so is taking steps to reduce emissions and the environmental impact of aircraft in general.

One of the most important initiatives is based in Europe and is 50 per cent funded as part of the European Commission's Seventh Research Framework Programme – with the remaining funding coming from industry. Known as the Clean Sky JTI (Joint Technology Initiative), the seven-year, €1.6 billion programme aims to accelerate the introduction of new, radically greener technologies in the next generation of aircraft. The Clean Sky’s JTI research programme, regulatory framework and Joint Undertaking statutes were formally adopted by the European Council of Ministers on 20 December 2007, following a positive vote at the European Parliament on 11 December.

According to ASD (Aerospace and Defence Industries Association of Europe), the Clean Sky initiative is the largest European research project ever and will help to meet the 2020 environmental goals set by ACARE (Advisory Council for Aeronautics Research in Europe) of a 50 per cent reduction in CO2 emissions, an 80 per cent reduction in NOx (nitrogen oxides) emissions, a 50 per cent reduction in external perceived noise and a green product life cycle (these reductions use 2000 as the baseline).

The Clean Sky initiative is built around six technology areas known as Integrated Technology Demonstrators (ITDs). Companies involved with Clean Sky will assess, design, build and test technological validation vehicles that will help the industry develop greener, more innovative aviation products. It is hoped that technology breakthroughs will be made in time for major fleet renewals in the period 2015 to 2025.
Ake Svensson, president of ASD and chief executive of Saab, commented at the time of the initiative's formal adoption: “Clean Sky JTI adoption is very good news and is the result of the personal commitment of Commissioner Potocnik and a clear political will of the Member States and the European Parliament, which I wholeheartedly endorse. It is a major initiative that will deliver innovative technologies and solutions, leading to a significant reduction in aircraft fuel consumption, noxious emissions and noise.

“The aeronautics industry is committed to helping society develop an effective response to the challenge of climate change. Clean Sky is the biggest public-private partnership ever to enable the aeronautics sector to address increasing public concern about the environment.”

Clean Sky founding members come from across the aeronautics sector, representing 86 organisations in 16 countries. As well as the industry's major players, the membership embraces 20 small to medium-sized enterprises, 15 research centres, 17 universities and the European Commission. Calls for tenders and calls for partners will be issued as appropriate during the course of the project, thereby increasing considerably the number of organisations participating and benefiting.

Integrated Technology Demonstrators

There are six Integrated Technology Demonstrators (ITDs) focusing on different but overlapping aspects of the Clean Sky project. The Eco-Design ITD, which is led by Dassault Aviation and Fraunhofer Gesellschaft, will input into all of the other five ITDs. Two of these are intended for applications across all vehicle types, namely the Sustainable and Green Engines ITD, led by Rolls-Royce and Safran, and the Systems for Green Operations ITD, led by Liebherr and Thales. The remaining three vehicle-based ITDs are Smart Fixed-Wing Aircraft, led by Airbus and Saab, Green Regional Aircraft, led by Alenia and EADS CASA, and Green Rotorcraft, led by Eurocopter and AgustaWestland.

In terms of timescales, it is intended that the initial technology selection and development phase will run until 2010, leading into a phase of demonstration design, preparation/modification and technology integration that will last until 2013. Flight tests will also commence in 2013 and continue into 2014. The latter part of 2014 is reserved for analysis and assessment.

The Smart Fixed-Wing Aircraft ITD (SFWA-ITD) will focus on two key areas: smart wing technologies and innovative powerplant integration. It is intended that there will be a large-scale flight demonstration of smart wing technologies to investigate, for example, natural and hybrid laminar flows, active and passive load control, novel enabling materials and innovative manufacturing schemes. There will also be a large-scale flight demonstration of innovative powerplant integration, looking at the impact of the airframe flow field on propeller design, the impact of open rotor configurations on the airframe, and innovative empennage design.

The Green Regional Aircraft ITD (GRA-ITD) is aiming to reduce CO2 and NOx emissions by 10 per cent each. This will be achieved by reducing fuel burn by 10 per cent through a reduction in the aircraft weight of nine per cent and a reduction in drag of six per cent. In addition, low-noise aircraft configurations will reduce external perceived noise by 10 dB.

Various enabling technologies will be explored, including sensors to monitor for in-service structural degradation, layered/multi-functional materials, nanotechnologies for materials, and advanced metallic structures such as fully laser welded integral structures and welded titanium fabrications. Furthermore, the GRA-ITD will also investigate ‘all-electric aircraft’ in which traditional hydraulic and pneumatic control systems are replaced by electrical systems.

The Green Rotorcraft ITD is operating in the context of an ACARE strategic research agenda (SRA2) that states that rotorcraft will play an increasing role in providing an affordable means of transport for point-to-point journeys compared with road transport. Three main areas of activity for the Green Rotorcraft ITD will be innovative configurations, novel engine integration and flight operations. More specifically, projects will investigate innovative rotor blades, ways to reduce the drag caused by the airframe and dynamic systems, the integration of innovative electrical systems, the use of diesel engines in light helicopters, environment-friendly flight paths, and eco-design for the rotorcraft airframe. Both helicopter and tilt-rotor aircraft should benefit from the ITD’s work.

In implementing the ITD's technologies, it is hoped that by 2020, airframe drag and download will have been cut by 10 per cent, rotor lifting efficiency will have improved by five per cent, and fuel consumption will have been cut by 30 per cent through the use of advanced diesel engines.

Eco-design ITD

The Eco-design ITD will investigate new materials and architectures, ‘clean’ manufacturing technologies, long-life structures that reduce maintenance and repair requirements, and end-of-life management processes relating to, for example, dismantling and recycling of aircraft components.

Three objectives for the Eco-design ITD are as follows: to validate an aircraft design methodology and tools for optimising an Integrated Vehicle Systems Architecture; to demonstrate the feasibility and ecolonomic (ecological and economic) benefits of the all-electric aircraft concept; and to prepare the ecolonomic design through a drastic reduction in ground and flight tests - which implies a move towards the ‘virtual aircraft’.

Key targets for the Engines ITD are to reduce CO2 emissions by 15–20 per cent, to reduce NOx emissions by 15–40 per cent and to reduce external perceived noise by 15 dB. The main areas of investigation will be new engine concepts (particularly the open rotor configuration) and advanced low-pressure and high-pressure technologies. By the end of the seven-year Clean Sky project, it is intended that there will be a proven architecture for advanced aero-engines, as well as mature, ready-to-use technologies.

Currently it is not clear whether the optimum configuration will be a pusher or puller engine, and whether the propfans will be driven directly or geared. However, the starting point for the demonstrator will be a direct-drive pusher engine.

The Clean Sky initiative is aiming to find ways to manage aircraft energy and aircraft trajectory and mission so as to help achieve the environmental objectives. By managing these, it is possible to reduce the fuel required by an aircraft to complete a given mission, and also minimise waste, while at the same time providing for aircraft and engine flexibility.

For example, in an all-electrical aircraft it would be possible to reduce demands for energy in some systems at those times when other systems are experiencing peak demand. By making more efficient use of the energy consumed onboard in this way, overall fuel consumption will be reduced.

In terms of managing energy, the most important aircraft functions will be considered as follows: primary power generation and distribution; auxiliary and emergency energy/power generation and storage; engine support; cabin and aircraft pressurisation; aircraft thermal management; flight control; ice and rain protection; and take-off, landing, taxiing and braking.

The branch of the Systems ITD investigating the management of the trajectory and mission will address the optimisation of both noise and fuel consumption, both for large and regional aircraft, by looking at the management of trajectory, management of mission, and smart ground operations. Within this last item, for example, the use of motorised landing gear could enable the aircraft engines to be idled during taxiing, thereby saving fuel and reducing ground noise.
Technology Evaluator

Standalone technologies will first be evaluated at ITD level. In addition, pre-designs of new aircraft concepts using one or a combination of Clean Sky technologies will be prepared by the ITDs. However, there will also be a Technology Evaluator that will take the new aircraft concepts and evaluate them against various operational scenarios, taking into account traffic and route forecasts for 2020 and beyond.

By substituting these concept aircraft for today’s reference aircraft, the Technology Evaluator will be able to assess the potential environmental improvements. Among the metrics to be used will be CO2 production, exposure of populations to noise, and the contribution made by air traffic to local air quality in the vicinity of airports.

Seven years may sound like a long time, but there is plenty of work to be done by an industry that is traditionally conservative. It will also be interesting to see how many of the more radical concepts make it through to the Technology Evaluator and beyond, but the end result should be worth the investment.

Tiltrotor offers the best of both worlds

The second prototype Bell/Agusta BA609 Tiltrotor aircraft made an appearance at the 2008 Farnborough International Air Show having flown in from Italy. During this flight, the Tiltrotor is said to have demonstrated excellent performance, flexibility and reliability while exercising its envelope in both vertical lift and high cruise speed airplane modes.

AgustaWestland describes the BA609 Tiltrotor as one of the most significant technological developments in the aeronautical world, offering unusually green and efficient capabilities. The BA609 Tiltrotor flight envelope includes an effective combination of a helicopter's vertical take-off and landing capability, together with the speed, range and comfort of typical turboprop airplanes. So far the development programme, based around four prototypes, has achieved more than 300 flight hours with the first two test aircraft (#001 in the USA and #002 in Italy); aircraft #003 is currently being assembled at the AgustaWestland facilities in Italy.

To date the flight test program has validated the BA609 flight envelope, including altitudes up to 25 000 feet and speeds up to 310 knots, all at the maximum weight. The test programme continues to check all the points of the flight envelope as required by both the FAA and EASA.
Highly versatile, the BA609 is suitable for a variety of applications including homeland security operations, surveillance and control of illegal traffic and immigration, and search and rescue  with the capability to perform rescues more than 500 km from the coast.
In 2007, the FAA froze the airworthiness certification basis for the BA609 Tiltrotor aircraft. Bell/Agusta and the FAA are continuing to work closely with EASA to achieve a dual FAA/EASA certification by 2011 or early 2012. So far orders for more than 80 aircraft have been placed by approximately 40 customers (including Government agencies) in over 20 countries.

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