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GRA - Green Regional Aircraft
Centro Sviluppo Materiali
Hellenic Aerospace Industry
| University Bologna
Other ITD Lead:
The Green Regional Aircraft, one of the six Clean Sky platforms, led by Alenia Aeronautica, involves 32 European partners among engine manufacturers, system engineering companies, research centres, universities, small and medium enterprises.
The future green regional aircraft will meet demanding weight reduction, energy and aerodynamics efficiency, an high level of operative performance, in order to be compliant regards to pollutant emissions and noise generation levels. To achieve these so challenging results, the aircraft will be entirely revisited in all of its aspects.
The GRA structure is as follows:
- GRA1 - Low Weight Configuration (LWC)
- GRA2 – Low Noise Configuration (LNC)
- GRA3 – All Electric Aircraft (AEA)
- GRA4 – Mission & Trajectory Management (MTM)
- GRA5 – New Configuration (NC)
and reflects its transversal nature by being organized in 5 domains, that in turn interface with the other JTI platforms, such as Eco-Design (EDA for Airframe with LWC, EDS for System with AEA), System for Green Operation with AEA and MTM, and Sustainable and Green Engine (SAGE) with NC.
The GRA1 Domain will consider all the solutions that may allow for considerable weight reduction, from the improvement of current composite materials with more innovative solutions such as multi-functional Layer and multi-layer architectures that can ensure electric conductivity and lightning resistance and a better acoustic insulation, to the introduction of new lower-density aluminium alloys.
Advanced manufacturing and assembly techniques will also be developed and tested.
The Domain will also review the possibility to use various sensor technologies embedded in the composite to monitor the health status of the structure and report the degradation of its mechanical properties as required.
The GRA2 Domain, will evaluate the effects of drag reduction of the aircraft with a view to reducing consumption and external noise. Drag in particular will be reduced, by using Natural Laminar Flow (NLF), that will be integrated with specific innovative anti-ice and high lift systems able to alleviate well-known drawback of NLF technologies. Flow and load control systems activated by electric fly-by-wire commands will be also investigated both for drag and weight reductions. In order to reduce external noise and drag the study will deal mostly with approaching and landing phase, improving high lift device (HLD) technologies. Gears will also require further aerodynamic optimization, with respect to past approaches, in order to reduce the turbulences they generate and consequently reduce noise.
The GRA3 Domain will consider the possibility to remove or minimise the source of pneumatic power (from the engine) and that of hydraulic power, which are both used for ice protection functions, for environment conditioning, cabin pressurisation, flight controls, gears extension and retraction, brakes activation, etc, and replace it with electric compressors, with a consequent greater thrust production efficiency of the main engine. This will be a step towards the so-called All-Electric Aircraft, where all on-board utilities will use only the electric power coming from generators connected to the engine.
The GRA4 domain is in charge of Mission and Trajectory Management activities specific for regional aircraft. The activities are performed in tight cooperation with Systems for Green Operations (SGO) ITD – WP3 in particular-, where technological studies are performed.
The main aim is to define optimized trajectories (optimised take-off and landing trajectories, as well as functionalities applicable to cruise phase) able to minimise emissions and the noise impact on the communities surrounding the airports. During these activities SESAR input will be taken into account as soon as available.
The overall idea is that GRA ITD defines regional aircraft requirements and MTM peculiar functionalities. Then, taking into account SGO ITD input, dedicated developments with respect to specific regional applications will performed. These green technologies will be integrated in a flight simulator, which will enable pilots to fly the new trajectories. The test results will be used to assess the environmental benefits deriving from these new green technologies with respect to the GRA targets.
GRA 5 domain aims at defining advanced regional aircraft general configurations integrating the innovative powerplants (including Open Rotors), Systems and Avionics best fitting the regional aircraft requirements, and the advanced aerodynamics and structures developed in GRA.
Airframe - Powerplant integration studies (innovative tail configurations, rear engine installation, shielding, vibration assessment) will be dealt in. NC is also the domain that will provide the Technology Evaluator with the GRA contribution to the achievements of the environmental impact reduction forecast.