An overview of the Clean Sky initiative, a Public Private Partnership between the European Commission and the Aeronautical Industry, set up to bring significant step changes regarding the environmental impact of aviation. We look at its set up, objectives, various Integrated Technology Demonstrators (ITDs) and some significant milestones, which have been achieved
by John Matthews
Clean Sky is intended to speed up technological breakthrough developments and shorten the time to market for new and cleaner solutions tested on full scale demonstrators, thus contributing significantly to reducing the environmental footprint of aviation (i.e. emissions and noise reduction but also green life cycle) for future generations.
The initiative claims to be the most ambitious aeronautical research programme ever launched in Europe. Its mission is to develop breakthrough technologies to significantly increase the environmental performances of airplanes and air transport, resulting in less noisy and more fuel efficient aircraft, hence bringing a key contribution in achieving the Single European Sky environmental objectives.
The Clean Sky JTI (Joint Technology Initiative) was born in 2008 and represents a unique Public-Private Partnership between the European Commission and the industry. It is managed by the Clean Sky Joint Undertaking (CSJU) and will be until 31 December 2017.
Technological breakthrough developments
The Clean Sky JTI is one of the largest European research programme ever, with a budget estimated at €1.6 billion, equally shared between the European Commission and industry, over the period 2008 – 2013. The objective of this unique public-private partnership is to speed up technological breakthrough developments and shorten the time to market for new solutions tested on Full Scale Demonstrators.
Speeding up new, greener design is essential to protect our environment. It should be kept in mind that aircraft have a 30-year service life, and that new aviation design takes more than a decade to develop. The accelerated research process that Clean Sky offers represents an unprecedented opportunity for rapid progress in the introduction of green technology into aviation.
Clean Sky will demonstrate and validate the technology breakthroughs that are necessary to make major steps towards the environmental goals sets by ACARE – Advisory Council for Aeronautics Research in Europe – the European Technology Platform for Aeronautics & Air Transport and to be reached in 2020:
- 50% reduction of CO2 emissions through drastic reduction of fuel consumption
- 80% reduction of NOx (nitrogen oxide) emissions
- 50% reduction of external noise
- a green product life cycle: design, manufacturing, maintenance and disposal / recycling
The initiative will encourage the participation of SMEs to ensure their full involvement in the programme, therefore offering opportunities to the entire aeronautic supply chain from all EU Member States and Associated countries.
Radically innovative
Clean Sky aims to create a radically innovative Air Transport System based on the integration of advanced technologies and full scale demonstrators, with the target of reducing the environmental impact of air transport through reduction of noise and gaseous emissions, and improvement of the fuel economy of aircraft. The activity will cover all main flying segments of the Air Transport System and the associated underlying technologies identified in the Strategic Research Agenda for Aeronautics developed by the Aeronautics Technology Platform ACARE.
Clean Sky is built upon 6 different technical areas called Integrated Technology Demonstrators (ITDs), where preliminary studies and down-selection of work will be performed, followed by large-scale demonstrations on ground or in-flight, in order to bring innovative technologies to a maturity level where they can be applicable to new generation “green aircraft”. Multiple links for coherence and data exchange will be ensured between the various ITDs:
- the SMART fixed wing aircraft ITD, focused on active wing technologies that sense the airflow and adapt their shape as required, as well as on new aircraft configurations to optimally incorporate these novel wing concepts
- the Green Regional Aircraft ITD, focused on low-weight configurations and technologies using smart structures, low-noise configurations and the integration of technology developed in other ITDs, such as engines, energy management and mission and trajectory management
- the Green Rotorcraft ITD, focused on innovative rotor blades and engine installation for noise reduction, lower airframe drag, diesel engine and electrical systems for fuel consumption reduction and environmentally friendly flight paths
- the Sustainable and Green Engine ITD will integrate technologies for low noise and lightweight low pressure systems, high efficiency, low NOx and low weight core, novel configurations such as open rotors
- the Systems for Green Operations ITD will focus on all-electric aircraft equipment and systems architectures, thermal management, capabilities for “green” trajectories and mission and improved ground operations
- the Eco-Design ITD will address the full life cycle of materials and components, focusing on issues such as optimal use of raw materials, decreasing the use of non-renewable materials, natural resources, energy, the emission of noxious effluents and recycling.
Indicators for 2012
Generally speaking, Clean Sky annual objectives are linked to the completion of the forecast operational tasks, the progress towards the technologies readiness, the environmental benefits assessment and the satisfactory sequence and outcome of calls for proposals and the further improvement of the JU’s quality management and internal control system.
A simulation network called the Technology Evaluator (TE) assesses the performance of the technologies developed, tracking progress towards the ACARE goals. A key milestone was reached in March 2012, when the TE completed its first full-scale simulation and performed the evaluation of Clean Sky’s progress at all three assessment levels (Aircraft, Airports and ATS).
The conclusions were:
- 130-180 seat, short/medium range aircraft equipped with open rotor engines and laminar-flow wing technology could deliver up to 30% better fuel efficiency and related CO2
- emissions reductions when compared to equivalent 2000 aircraft
- next-generation regional aircraft for 90-130 passengers using advanced turbodrop and turbofan engines (incluing a new Clean Sky ‘geared turbofan’ solution), and incorporating advanced aerodynamics, structures and energy-efficient systems show similar potential – against today’s best in-service aircraft
- important reductions in noise nuisance are foreseen in business aviation and rotorcraft operations. For instance, new business jet designs could deliver a 2/3 reduction in noise affected areas during take-off.
- Clean Sky has successfully implemented a unique Technology Evaluation process involving robust and independent analysis of performance gains and extensive simulation of aircraft in airport and air transport system level scenarios.
As it moves forward, each year Clean Sky’s progress will be evaluated and reported. Here are some further plans and ongoing progress surrounding Clean Sky’s integrated technology demonstrators (ITDs).
Smart fixed wing aircraft
In 2012, the majority of activities in the SFWA-ITD were related to the detailed design and manufacturing of the major flight test demonstrators. In particular the building of the two laminar wing articles for the so called Airbus A340-300 based “High Speed Demonstrator Passive” will start in the year 2012. To prepare the “Low Speed Demonstrator” the programme was updated due to the different levels at which the principle required technologies are to date. As a result, as intermediate step, two ground test demonstrators, one for a so called “smart flap” and one for an active system to attenuate vibration due to flow separation, were initiated in 2012. The decision for low speed flight tests will be made after year 2012 based on the outcome of these ground tests. According to the current provisional planning year 2012 and 2013 do require the highest level of CleanSky “Call for Proposal” -partner activities in the program.
The development, integration and large scale ground and flight testing of the SFWA-ITD technologies are basing upon a structured maturation of the underlying principle technologies. In 2012, the majority of technologies were advanced at technology readiness levels between TRL3 and TRL4, which means that the majority of activities will be dedicated to the integration and ground testing of principle technologies into components in an integrated environment.
In addition a total number of 15 research and industry type wind tunnel tests were planned for 2012, the highest figures in a single year in the SFWA-ITD concepts, and the design of riblet surface coatings. At least one wind tunnel test is.
Green regional aircraft
GRA will continue the work packages defined in the baseline program, with internal review of the technologies to be further enhanced.
GRA will also integrate in the plans of each WP the activities conducted by the partners selected by means of the CFPs issued 2010 and 2011.
The areas of interest are the following:
- GRA1 – Low Weight Configuration (LWC) domain
- GRA2 – Low Noise Configuration (LNC) domain
- GRA3 – All Electrical Aircraft (AEA) domain
- GRA4 – Mission and Trajectory Management (MTM) domain
- GRA5 – New Configuration (NC) domain
LWC domain will be largely involved in manufacturing and final testing of large scale structural panels in order to perform the “second down selection”. These panels will be tested for different technologies selected after the “first down selection” based on coupons testing.
Major activities in LNC domain will be carried out for “High Lift Devices (HLD)” technology, “Natural Laminar Flow (NLF)” and “Main Landing Gear/ Nose Landing Gear (MLG/NLG)” technologies in order to perform the “second down selection”.
Further improvement to all electric architectures, being AEA domain a major contributor to Flight test with some advanced systems (WIPS, ECS, EMA etc.) equipment and Energy Management Systems. Flight Test is currently planned using an ATR aircraft and, after the feasibility studies performed on year 2011, the assessment will be performed to prepare the PDR (Preliminary Design Review) with design of the modifications to apply on aircraft will start later.
Green rotorcraft
In the six technology areas, the activities progress further with manufacturing and testing of components aiming to prepare the final integration and demonstration.
- GRC1 – innovative rotor blades
- GRC2 – drag reduction of airframe and non-lifting rotating systems
- GRC3 –integration of innovative electrical systems
- GRC4 – integration of a diesel engine on a light helicopter
- GRC5 – environment-friendly flight paths
- GRC6 – eco-design for rotorcraft airframe
- GRC7 – interface with the technology evaluator
Sustainable and green engines
The focus in the programme has been largely expended in preparing for demonstrations: defining technology demonstration requirements and validation strategies, managing the risk to engine demonstrations by raising the Technology Readiness Level of selected technologies through sub-system rig testing, developing engine test component designs and enabling manufacturing technologies and reviewing the demonstrator plans.
Key decisions and significant commitments made in 2012 will freeze the demonstrator configurations and finalise the technological designs. Components will be manufactured and demonstrators assembled and delivered for test, with the first engine demonstrations in projects SAGE3 and SAGE5 scheduled to be completed. A major change is the introduction of SAGE 6, dedicated to the flight test of a “Lean Burn” system, based on a novel combustion chamber and able to provide for a further NOx reduction of more than 30%.
Systems for green operations
The major areas of this ITD are concentrated in the WP2 (Management of Aircraft Energy) and in the WP3 (Management of Trajectory and Mission). WP1 and WP4 aim at defining the requirements and performing the validation whereas the WP5 is about the overall assessment.
EcoDesign
Eco-Design ITD is organized in the two major areas of EDA (Eco-Design for Airframe) and EDS [Eco-Design for Systems (small aircraft)]. The EDA part of the Eco-Design ITD is meant to tackle the environmental issues by focusing on the following challenges:
- to identify and maturate environmentally sound (“green”) materials and processes for a/c production.
- to identify and maturate environmentally sound (“green”) materials and processes for a/c maintenance and use processes.
- to improve the field of end-of-life a/c operations after several decades of operation, including reuse, recyclability and disposal (“elimination”) issues.
- to provide means for an eco-design process on order to minimize the overall environmental impact of a/c production, use/maintenance, and disposal.
