Disruptive technologies related to the airframe will have to be integrated with ultra-efficient propulsion systems, together with multi dimensional trade-offs, including sustainability and circularity. Further energy efficiency gains can be achieved by transitioning to more electric or hybrid electric systems with a significantly higher demand of electric power in the MW class, while demanding lighter, more efficient, and highly independent systems. The resulting ultra-efficient SMR targets a 30% CO2 emission reduction from technology, not taking into consideration the SAF net-effect, on a typical mission.

A MW class aircraft architecture enabled by high voltage/high power generation, conversion, distribution, transport, and storage, considered for the future SMR aircraft concept, implies a step change (up to 5 times more) electrical power generated, stored, and distributed. It comes with the need to manage several electrical networks of different voltages (HVDC on top of more classical 115VAC/28DC), some electrical loads moving to high voltage (800VDC) while most loads remain in classical voltage levels.

The scope of the topic, therefore, is to design, develop, demonstrate, and deliver an SMR system architecture and components for an on-ground demonstration up to TRL5, including:

• Overall system architecture, addressing:
  • Further architecture configuration trade-offs and optimisation.
  • Electrical, thermal and energy management functions, at the requested performance targets (detailed in the next section) for an SMR aircraft and Ground Test Demonstrator.
  • The Validation and Verification approach of the integrated end-to-end electrical system towards on-ground demonstration at TRL5 by 2027, including means associating models, real hardware in the loop and remote testing capability.
• Electrical Power Generation and Distribution System (EPGDS – ATA 24/ATA92), including:
  • Definition and substantiation of the architecture achieving minimum weight (target to be defined at proposal stage).
  • Non-propulsive power sources and generators (including starter generator).
  • Power conversion units required to generate different voltage and power levels considered at aircraft level, for non-propulsive and propulsive consumers.
  • Harness and connectors to enable the interconnection of equipment.
  • Power distribution units, protection devices, and fault management for the EPGDS.
  • Energy management and health monitoring.
  •  Grounding and bonding definition to mitigate conducted and radiated emissions accounting novel designs of the airframe.
  • Protection and mitigation of adverse physical phenomena associated with severe environmental condition at altitude such as partial discharge, arcing and lightning effects at high voltage, pressurised, low pressurised and non-pressurised areas.
  • Energy Consumption, covering technology brick maturation to TRL5 via ground tests and a clear route to integration into an end-to-end overall electrical system architecture, tackling the challenges of integration with the aircraft electrical power generation and distribution system to be tested on-ground at a later stage during the programme, covering.
  • Maturation of the Electric Engine Start, without adding significant energy consumption and weight than the traditional bleed based starting system.
  • Maturation of Electric Environmental Control System (eECS), Air Supply and Cabin Heating (ATA21) optimised for power consumption, weight, and sizing for a moreelectric aircraft, as compared to a traditional bleed-air based thermal management system.
  • Maturation of interfacing of Electric Ice Protection System (eIPS) (ATA30) towards a fully integrated solution with power generation and distribution system, to deliver an optimised and efficient energy management with minimum energy required for ice protection / de-icing.
  • Demonstration of operationality of an Electric Actuation System, and potential energy management logics to ensure a safe operation of the function, with an objective to establish an optimum energy management strategy.
• Electrical Energy and Thermal Management, including development and integration of:
  • advanced load management functions: systems shall be able to reconfigure their operations in terms of voltage and/or current and/or power levels, by following optimisation logics involving whole powertrain and leveraging novel concepts such as smart grids and parallelisation of electrical flows;
  • advanced electrical energy management systems: electrical power flows management shall be aligned with aircraft level energy control, supported by new sensors as appropriate, allowing minimisation of energy consumption and thermal loads depending on flight phase and conditions;
  • thermal management solutions with the different heat sources coming from the aircraft electric energy generation and distribution, batteries, and other energy consumers;
  • the realisation and validation of an integrated electrical energy management function structured as a supervisory control, that would be hosted on a representative avionics platform.

Performance Targets: A set of top-level goals will be the basis for performance targets, in particular:

• Contribute to 30% CO2 emission reduction for the SMR aircraft concept, without the inclusion of 100% SAF fuels, and to 86% CO2 reductions when 100% SAF is considered (assuming an 80% carbon footprint of SAF on average). This KPI is based on 2020 state-of-the art technologies, paving the ground towards CO2-neutral aviation by 2050.
• To achieve this, a 20% or greater CO2 emission reduction (without SAF) is expected for the propulsion system, when integrated at aircraft level. The on-board systems optimisation shall indirectly enable this CO2 reduction by:
  • Delivering the adequate electrical / thermal / energy performance needed to achieve at least 1% fuel burn improvement and 150kg/flight CO2 equivalent.
  • Weight, volume, and reliability optimisation of the systems, sub-systems and equipment, to minimize the impact of their integration at aircraft level and achieve the highest possible power density without compromising performance. The applicant will provide an estimate at start of the main characteristics of targeted performance (weight, performance and volume) considered essential for the future aircraft concept for an EIS in 2035 o Targets must be compatible with safety as an overarching requirement and with future exploitation objectives in term of reliability and competitiveness, and consistent with the certification path, including the CRL 4 objective (refer to the Description of the call topic and topic specific conditions).

These top-level goals should be broken down in a consistent manner at the different levels: from top level aircraft requirements down to systems, sub-systems, and components level requirements, from where pertinent performance targets including Key Performance Indicators (KPIs) should be derived.