CFPs: Flight Test Demonstration of an Unducted Engine Architecture for SMR Aircraft

Deadline: 15 May 2025

The European Commission is seeking proposals for the Flight Test Demonstration of an Unducted Engine Architecture for SMR Aircraft topic.

Scope

This topic is intended to deliver an ultra-efficient unducted engine architecture installed on aircraft expected to meet, by project completion, an unducted propulsion system architecture at TRL6, to be flight tested in real operating conditions as a validation for the propulsion architecture. Applicants should propose and build a demonstration plan aiming at validating an unducted propulsion architecture in flight by the end of 2028.
Applicants should demonstrate TRL4 already completed and achieved for unducted engine architecture key technologies necessary for FTD at project start, based on synergies with activities from CA Phase 1, or funded by national/regional or other European programmes, and identify the remaining key challenges in the path towards TRL6 by end 2030.
The overall scope of the topic stems from the aim of validating an SMR unducted engine architecture demonstrator in flight test at TRL6 to demonstrate the expected CO2 emissions reduction at aircraft level. The engine activities include the whole propulsion system, for example, including the multifunctional cowls. The scope covers the following activities:
- Flight test preparation, covering
  - Engine preparation, including:
    - manufacturing and assembly, including instrumentation installation and calibration, of a Flight Test Demonstrator (FTD) engine.
    - advanced instrumentation (such as telemetry) installation and calibration.
    - definition, manufacturing, installation, and calibration of Flight test data acquisition and recording means.
    - specific logistic means definition and manufacturing, to transport the full engine from the assembly shop to the test sites (including engine handling means during tests)
  - Aircraft preparation, including:
    - finalization of design activities, launch and completion of manufacturing and assembly/adaptation onto the aircraft of aircraft systems (both hardware and software) and airframe adaptations
    - development and acquisition of the relevant flight instrumentation, fulfilling the performance targets detailed in the next section, to carry out in-flight measurement of thrust, emissions, and other characteristics such as noise and soot, and flow past the unducted fan. The technologies developed should reach the maturity of TRL6 during the project timeline and fulfil the need for in situ measurements and access hard-to-reach areas.
    - completion of flight test related installations and engine monitoring station, mechanical and electrical interface, power supply and mechanical bay.
    - conversion of aircraft into FTD platform aircraft, to reach unducted FTD configuration readiness, including powerplant installation and integration on aircraft.
    - identification flights to calibrate instrumentation before performance tests.
    - Design & manufacturing of necessary related ground support equipment.
  - Flight Clearance activities and supporting activities, including:
    - verification of aerodynamics, handling qualities, aircraft loads and performances analysis against simulations and wind tunnel tests to support flight clearance and flight test campaign.
    - Completion of Lab Test Means development and necessary tests to get Flight Clearance, Flight Clearance process with flight readiness reviews preparation, flight clearance reports and validation for both the FTD engine and the FTD aircraft platform.
    - Preparation and execution of engine specific Rig Tests to support the Flight Clearance (such as bird ingestion, fan pitch actuation system verification, fan blade out, fatigue tests, lighting tests etc.).
    - Wind tunnel tests to support Flight Clearance.
  - Flight analysis preparation and supporting activities, including:
    - Wind tunnel test to optimize the unducted fan installation.
    - Finalization of in-flight thrust determination methodology and test analysis process at the engine and aircraft integration level.
    - Definition and update of tailored flight test configuration models of the engine (aerodynamic, acoustics, dynamic, etc.) based on FTD component and systems definition accounting for blueprint definition and deviations and define pretest predictions.
    - Verification & Validation activities both at the engine level and the FTD aircraft platform.
  - Flight tests execution, covering:
    - Performance of FTD engine pre-flight tests on ground, FTD campaign to assess unducted engine performances (propulsive efficiency, acoustics, etc.).
    - Flight Test preparation and operations and related support.
  - Flight test data post-processing and analysis, covering:
    - FTD campaign data delivery.
    - Analysis and reconciliation of FTD campaign data down to techno bricks at engine level.
    - Perform engine and aircraft models calibration and correlation based on flight test analysis
  - Maturation of relevant major modules in the powerplant system to support demonstration of TRL6 of the unducted propulsion system architecture. This should result in a reduction of the performance margins and uncertainty at the engine demonstrator level. Potential systems may include:
    - Reduction gearbox
    - Low pressure turbine and mid/rear turbine frames
    - Advanced structures, including additive manufacturing and novel materials
  - Contribution to performance targets of the SMR aircraft concept with EIS by 2035, based on models taking into account:
    - The FTD results
    - High efficiency Fuel and thermal systems that enable the use and benefits of drop-in 100% SAF usage, and further developed for non-drop in SAF system benefits e.g. due to higher calorific value, thus improving thermal efficiency.
    - Optimized engine-aircraft integration considering aerodynamic, structural and systems improvements to reduce weight and increase efficiency, for the targeted aircraft concept

Funding Information

The maximum EU contribution for the topic is EUR 100 million.
The maximum EU contribution per project funded under this topic is EUR 100 million.
Indicative project duration: Maximum 48 months.

Expected Outcomes

Project results are expected to demonstrate an unducted propulsion system architecture with a sealevel static thrust of 25000 to 30000lbf in flight at TRL6 for a Short Medium Range aircraft concept considered by Clean Aviation SRIA for EIS in 2035:
- Prepare flight tests
  - Deliver a flight test demonstrator for an unducted propulsion system architecture, going through design finalisation (CDR closing), manufacturing, instrumentation integration & calibration, and assembly of all engine parts. Include Wind Tunnel Tests to optimize and verify engine installation on Flight test demonstration platform.
  - Deliver an ultra-advanced fully instrumented flight test demonstration platform enabling full-scale flight-test demonstration of the integrated unducted engine architecture, to perform propulsion system assessment in an SMR representative flight envelope (Mach, altitude) to validate the expected propulsive efficiency.
  - Deliver and demonstrate flight test instrumentation for emissions and thrust, soot and in-flight noise measurement, reaching TRL6, enabling in situ measurement, suited to areas with limited access. In-flight measurement technologies should be demonstrated for challenges associated with innovative propulsion architectures, such as characterization of the flow field.
  - Obtain flight clearance.
- Execute flight tests to achieve TRL6 by completing flight testing of the unducted propulsion system architecture on a relevant aircraft platform, ensuring the validation of performance contribution of the flight-tested technologies to at least 20% of C02 reductions at aircraft level for an SMR type engine by end of 2028.
- Flight test data processing and analysis to demonstrate the unducted engine architecture in terms of propulsive efficiency, noise impact, and architecture viability at TRL6.
- Feeding and calibrating advanced modelling tools, based on results from flight tests, for product vision design and optimization.
  - The reduction potential of at least 20% CO2 emissions at aircraft level should be validated, based on demonstrated technology performance after flight tests.
  - The key parameters and exhaust emissions linked to non-CO2 effects (including but not limited to NOx, water vapour, and non-volatile Particulate Matter) should be evaluated, monitored and reported against regulations on non-CO2 aviation effects (Directive (EU) 2023/958) for assessments of compliance.
  - Performance Predictions: provide an estimate of performances (CO2 and non-CO2) representative of the final engine architecture with all components emulated in their final expected configuration (performance-wise)
- Route to TRL6
  - Provide a roadmap to TRL6 for all engine parts with identification of their current level of maturity and propose a maturation plan for implementation.
  - Mature additional relevant enabling technologies and modelling capabilities, to support the demonstration towards TRL6 of the unducted propulsion system architecture; activities may include both component and sub-system rigs.
  - With regards to certification, EASA Certification Readiness Level (CRL) framework shall be used to demonstrate a clear certification path. It is expected that the activities identify the roadmap and action plan toward framework readiness aligned with the route to CRL6 at aircraft level by the end of CA programme.
- Project results are expected to directly contribute to the performance targets of the SMR aircraft concept with EIS by 2035:
  - The propulsion system shall enable and contribute to a 30% CO2 emissions reduction at aircraft level (including weight and aerodynamic integration effects of the propulsive system), compared to the 2020 SoA aircraft (enabling 86% net CO2 reduction with 100% SAF).
  - Evaluation, monitoring and reporting of key parameters needed to assess non-CO2 effects and noise emissions, shall ensure compliance with foreseen regulations and standards for a 2035 EIS.
  - Adequate KPIs at integrated system and key technology levels shall be defined, to support the effective achievement of the expected outcomes, and shall be aligned with the performance targets
  - A clear route towards certification, exploitation, and industrialization shall be identified, including the identification of operational requirements to subsequently support successful entry into service.

Eligibility Criteria

Entities eligible to participate:
- Entities eligible to participate Any legal entity, regardless of its place of establishment, including legal entities from nonassociated third countries or international organisations (including international European research organisations) is eligible to participate (whether it is eligible for funding or not), provided that the conditions laid down in the Horizon Europe Regulation have been met, along with any other conditions laid down in the specific call/topic.
- A ‘legal entity’ means any natural or legal person created and recognised as such under national law, EU law or international law, which has legal personality and which may, acting in its own name, exercise rights and be subject to obligations, or an entity without legal personality .
Entities eligible for funding :
- To become a beneficiary, legal entities must be eligible for funding. To be eligible for funding, applicants must be established in one of the following countries:
  - the Member States of the European Union, including their outermost regions:
    - Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden.
  - the Overseas Countries and Territories (OCTs) linked to the Member States:
    - Aruba (NL), Bonaire (NL), Curação (NL), French Polynesia (FR), French Southern and Antarctic Territories (FR), Greenland (DK), New Caledonia (FR), Saba (NL), Saint Barthélemy (FR), Sint Eustatius (NL), Sint Maarten (NL), St. Pierre and Miquelon (FR), Wallis and Futuna Islands (FR).
  - countries associated to Horizon Europe;
    - Albania, Armenia, Bosnia and Herzegovina, Faroe Islands, Georgia, Iceland, Israel, Kosovo, Moldova, Montenegro, New Zealand, North Macedonia, Norway, Serbia, Tunisia, Türkiye, Ukraine, United Kingdom.