To reduce climate impact of aviation, decarbonisation is a major challenge. Current combustion chambers are burning hydrocarbon fuels, such as kerosene or more recently emerging SAF products. Hydrogen is also considered today as a promising energy carrier but the burning of hydrogen creates radically new challenges which need to be understood and anticipated. HESTIA specifically focuses on increasing the scientific knowledge of the hydrogen-air combustion of future hydrogen fuelled aero-engines. The related physical phenomena will be evaluated through the execution of fundamental experiments. This experimental work will be closely coupled to numerical activities which will adapt or develop models and progressively increase their maturity so that they can be integrated into industrial CFD codes. Different challenges are to be addressed in HESTIA project in a wide range of topics: - Improvement of the scientific understanding of hydrogen-air turbulent combustion: preferential diffusion of hydrogen, modification of turbulent burning velocity, thermoacoustics, NOx emissions, adaptation of optical diagnostics; - Assessment of innovative injection systems for H2 optimized combustion chamber: flashback risk, lean-blow out, stability, NOx emission minimisation, ignition; - Improvement of CFD tools and methodologies for numerical modelling of H2 combustion in both academic and industrial configurations. To this end, HESTIA gathers 17 universities and research centres as well as the 6 European aero-engine manufacturers to significantly prepare in a coherent and robust manner for the future development of environmentally friendly combustion chambers.

The CENTRELINE project aims at maximising the benefits of aft-fuselage wake-filling under realistic systems design and operating conditions. The concept realises fuselage wake-filling through a single propulsive device installed at the fuselage aft-end with the purpose to entrain and re-energise the fuselage boundary layer flow, the so-called Propulsive Fuselage Concept (PFC). The aft-fuselage propulsor is driven turbo-electrically with power supplied through generator off-takes from advanced geared turbofan engines in under-wing installation. CENTRELINE will perform the proof of concept and initial experimental validation for a highly promising propulsion-airframe integration approach in order to mature this technology from currently TRL 1-2 to TRL 3-4. Advanced pre-design methods based on high-fidelity numerical simulation and integrated multidisciplinary design optimisation techniques will be adopted in order to produce best and balanced design solutions for the concept. The technological key features will be initially validated through physical experiments including scale-model wind tunnel testing for the overall configuration as well as specialised aerodynamic rig testing of the boundary layer ingesting aft-fuselage propulsor. The proposed research and innovation actions represent the immediate exploitation of results of the highly successful FP7 L-0 project “DisPURSAL” (GA no. 323013). The optimised system technology concept will be eco-environmentally benchmarked against an advanced conventional reference aircraft equipped with aerodynamic, structural, power plant and systems technologies suitable for a potential Entry Into Service (EIS) year 2035, referred to as "R2035". The objective CO2 reductions of the concept at integrated vehicular level are -11% against the R2035 (which means –40% CO2 versus the Y2000 SRIA reference). A detailed technology roadmap will be developed, indicating how to transfer these improvements to TRL 6 in 2030.

The SMR Aircraft Architecture and Technology Project (SMR ACAP) shall be the central place to assess and integrate all technologies at aircraft level, from across the projects in the SMR pillar. Establishing the link to projects with relevant technologies in the other Clean Aviation "Pillars" and transverse projects associated with novel certification methods is part of the work plan of the project. The setup of the ACAP project is tailored to steer and manage the definition of the targeted SMR aircraft configurations with all key performance features required for the SMR architecture. In order to accelerate the maturation of the SMR aircraft technologies, ACAP will provide a digital collaborative framework with tools, means and skills enabling to continuously link all R&T activities within the SMR pillar (strongly linked to other Clean Aviation pillars) to deliver solutions meeting the Clean Aviation high level goals: reduce the greenhouse gases by -30% compared to a 2020 state of the art technology; support the launch of new product by 2035, to replace 75% of the fleet by 2050, and exploit the synergies with other national and European related programmes. Coordinated by Airbus, the project consortium is composed of a well balanced mix of innovative actors from the aeronautical industry covering almost all technical disciplines of aircraft R&T complemented by a strong foundation of Academia and Research and Technology Organisations, which will be further widened with the planned linking to other CA projects. The ACAP project is aiming to identify "best athlete" SMR aircraft concepts before the end of CA phase 1 and, based on sound analysis of the expected impact with respect to the CA objectives, to propose which technologies shall be further developed and demonstrated in a Clean Aviation phase 2.

Engines ITD will work towards radical engine architectures and new engine technologies to power the aircraft of the future. The objective is to increase fuel and energy efficiency of the engine and reduce environmental impact, regardless of whether the engine is powering a large airliner or just a small utility aircraft, meaning more thrust while burning less fuel and emitting less CO2, NOx and noise.