The project progress and main results of IMOTHEP's six technology streams are showcased here below:
Integrated Vehicle Design
The central focus of IMOTHEP is on the exploration of technologies for hybrid-electric propulsion (HEP) chains, which need to be studied in close relation with aircraft mission and configuration to derive
relevant specifications for the investigation of electric components, such as the power requirements and the operational constraints. In addition, previous studies have shown that the integration of HEP could
lead to drastic changes on aircraft architecture to maximize benefits of this revolutionary type of propulsion, for example through the use of distributed electric propulsion (DEP) or boundary layer ingestion
In this context, the role of integrated vehicle design in IMOTHEP is to manage the consistency of technology integration at aircraft level through the achievement of three successive design loops. After
setting-up the Top Level Aircraft Requirements (TLARs), the design space for Regional (REG) and Short-Medium Range (SMR) hybrid electric configurations will
be explored at conceptual, detailed and refined levels. This will provide the requirements for the aero-propulsive integration and the definition of the hybrid-electric power chain, while, in a subsequent step,
it will allow to incorporate the results of technological studies in the overall aircraft design process.
Concepts under investigation for REG (top) and SMR (bottom)
Despite the Covid-19 situation, these activities could follow a nominal hot start since the beginning of the project. A first design workshop was organized to define the set of TLAR under the supervision of
Airbus and Leonardo, to determine the configurations to be explored and the HEP initial technology assumptions. The conceptual design loop has been kicked off and the four design teams (BHL, DLR, NLR and
ONERA) are producing the first results on near- and long-term concepts for both REG and SMR missions, and feeding subsequent research components with initial designs. Meanwhile,
teams from CHALMERS, CIRA, INCAS and ILOT are working on specific disciplinary modules, such as Boundary Layer Ingestion (BLI), HQ (Handling qualities) and structural sizing, which will be used in the design
IMOTHEP vehicle concepts: Transition from loop 0 to loop 1
Aiming at providing consistent aircraft configurations to integrate HEP architecture and components and evaluate the benefits, this Overall Aircraft Design activity has recently achieved an important
milestone: based on TLARs and technology assumptions, design teams have proposed first layouts for the four configurations under study and started to feed the component studies with targets and interface
Conceptual Design Loop: First regional and SMR aircraft versions
The second half of 2020 was dedicated to the consolidation and synthesis of the overall aircraft design activities by the design teams. Based on TLARs (Top Level Aircraft Requirements) issued by Leonardo (for
regional aircraft, REG) and Airbus (for short- and medium-range aircraft, SMR), two configurations per mission were proposed:
1. A so-called “conservative” version, keeping the tube and wing architecture, using a boosted turboshaft for the regional aircraft (coordinated by BHL), and using underwing distributed propulsion for the
SMR (DRAGON configuration, coordinated by ONERA).
2. A so-called “radical” version, aiming at more innovative aeropropulsive integration, using distributed propellers for REG (coordinated by DLR), and a Blended Wing Body accommodating Boundary Layer
Ingestion for SMR (coordinated by NLR).
These studies enabled to provide interface requirements and performance targets to the component designers, allowing to kick off the preliminary design loop (project “Loop 1”) through a second Design
Next steps: Towards the integration of HEP components
As activity is ramping up in the other work packages, the Overall Aircraft Design teams are preparing to accommodate the incoming results regarding aeropropulsive integration (especially DEP and BLI
modelling), energy generation solutions (batteries, turboshaft, generators, fuel cells), electric power unit (cables, converters, power cores, electric machines), and architecture performance (power and
thermal management, safety, EMC). Refining the performances and layout of the propulsive power train will enable to refine the aircraft design, and extend the exploration to novel options, using enhanced
design processes relying on collaborative technologies (with interactions with the H2020 AGILE/AGILE4.0 project).
The aircraft integration studies in IMOTHEP have entered a new critical step with the first feedback on component design studies. Flowing from aero-propulsive design, electric architecture definition,
energy generation and electric power technology studies, updated technology figures and new insights into integration constraints are progressively refreshing our four aircraft concepts. Meanwhile, as the
design becomes more and more intricate, advanced collaborative methodologies are required. On this point, an exchange with the H2020 AGILE4.0 project will be beneficial.
Fig. 1: Features of the REG-RAD plug-in hybrid configuration (credit DLR)
Towards the refinement of aircraft concepts
To foster collaboration between specialists, work within the ongoing multidisciplinary design loop is progressively organized per aircraft configuration, even if some technological developments remain common
to several concepts.
For the REG-CON configuration (boosted turboshaft concept led by BHL), a significant focus was placed on battery integration, incorporating feedback from AIT and KIT battery experts, and downselecting the
most promising battery pack location, considering operational constraints provided by the airframer Leonardo.
The REG-RAD configuration team (distributed propulsion plug-in hybrid led by DLR) has proposed a revision of the hybridization strategy, defining a concept flying fully electric for short missions under 200
km and using a range extender for longer distances. Special attention is paid to the propeller-wing interaction assessment with the help of aeropropulsion experts.
Fig. 2: Baseline airframe of the SMR-RAD configuration (SMILE airframe, credit ONERA)
The SMR-CON configuration (transonic turboelectric distributed fan concept led by ONERA) now incorporates consolidated data on electric motors and electric generator design and will be a use case for a
sensitivity study on the (challenging) voltage level between 1kV and 3kV, highlighting the benefits and drawbacks.
The SMR-RAD configuration team (turboelectric BWB concept with distributed fans and BLI effect led by NLR) concentrated on the refinement of the airframe design based on the ONERA SMILE configuration, and the
detailed design of fan and intake arrangement to enable CFD assessment of the BLI effect. Superconducting machines are currently being studied for this configuration.
Fig. 3: Design structure matrix of the SMR-CON configuration (credit ONERA).
Mastering complexity using advanced design methodologies
Given the increasing data flow between experts, it is crucial to maintain consistency between assumptions at the component, architecture and aircraft levels. A particular effort has been made to provide an
inventory of the models and their interface with the aircraft design process.
In that perspective, extended Design Structure Matrices of each concept were created to identify the contributing disciplines and the data exchange between them, utilizing the partners’ expertise in data
format, process automation and MDO technologies.
To go one step further, a joint workshop with the H2020 AGILE4.0 project will be held in the coming weeks, highlighting the complementarity of the tools and approaches developed in this methodological
project, and the concrete aircraft design cases of IMOTHEP.
As the multidisciplinary design loop nears its end, preliminary design reviews will be organized for each of the four concepts, enabling to feed the gap analysis of HEP technologies and to downselect the most
promising configuration for regional and SMR missions. The detailed design loop will then consist in refining the layout of the concepts and assessing their performances alongside the operational mission,
including transient effects.
These activities target overall aeropropulsive integration. More specifically, they aim to identify key propulsor design parameters, optimize the overall powerplant/platform layout and interaction, and assess the
potential performance of the more radical architectures. The topics range from specific propulsor module design to overall energy accounting methods and also cover noise assessment.
Most of these activities will gradually start in the coming months. However, the "Aeropropulsive Integration" activities have started gathering state-of-the-art propulsive efficiency applicable to IMOTHEP
aircraft architectures to support the down-selection of preliminary platform features for the integrated vehicle design.
Design study to maximise BLI effect (AIAA 2009 -1132)
To guide the Loop 1 aircraft design activities, low fidelity propulsor performance models were created for both the distributed propeller configuration (for the Regional Radical configuration) and the
distributed fan layout with boundary layer ingestion (for the SMR Radical configuration). In parallel, modular optimization activities made progress in terms of fan design (able to deal with boundary layer
distortion profile), parametrization of inlet shapes (to maximize pressure recovery), and nacelle shapes (integrable into the BWB fuselage layout).
REG-RAD aeropropulsive integration
Several parametric propeller designs were created based on the requirements of Loop 0. Side studies allowed to determine the dependency of propeller efficiency on thrust distribution over the wing. A fast
prediction tool for wing aerodynamics covering high- and low-speed conditions has been set up to be combined with propeller performance, enabling the Integrated Vehicle Design team to get a consistent parametric
view of expectable propulsive efficiency on the Regional Radical configuration.
Figure 1: Parametric wing model for aeropropulsive integration accounting
Figure 2: Preliminary propeller design
SMR-RAD aeropropulsive integration
The integrated high-level parametric study from the design phase, which used preliminary effects of boundary layer ingestion on propulsive efficiency, allowed us to determine the optimal number of ducted
propulsors for the SMR BWB configuration. In the subsequent design phase, the fan module characteristics were determined. The optimization currently underway will enable us to select the most efficient
configuration, taking into account the effects of boundary layer distortion.
Together, European and Canadian partners parametrically defined inlet and nacelle geometry to enable an optimization study that considers the geometric integration constraints for the fuselage layout.
Finally, methods and toolchains have progressed through the ducted fan body force modelling to assess off-design behaviour, the overall energy and exergy accounting of this complex and close-coupled
airframe-propulsion configuration, and the process for assessing noise sources and community noise.
Figure 3: Integrated fan module design under distortion
optimize both configurations with a higher degree of fidelity, using the refined set of specifications elaborated within the “Integrated Vehicle Design” phase;
conduct the final noise assessment of both SMR-RAD and REG-RAD configurations;
perform a detailed energy balance of the SMR-RAD configuration with respect to boundary layer ingestion, enabling exact accounting of its energy efficiency.
The architecture of a hybrid-electric propulsion system defines in which way sources and intermediate storages of energy are connected with consuming propulsion systems. By its topology, the electrical
architecture defines key degrees of freedom for overall aircraft operation and thereby contributes to safety and optimal use of energy.
Redundancy is required for safety and reliability. Hazardous failure scenarios need to be avoided by a reconfiguration of the system in case of failure of any component.
Reducing the peak load of generators enables weight savings through smaller component dimensioning and is achieved through modern energy management.
Thermal capacities and heat dissipation limit the degree of freedom for energy management and also set power limits. Active thermal management is thus also part of the electrical architecture.
Initial architectures (SMR): Schmollgruber, P., Donjat, D., Ridel, M. C., Atinault, O., & François, C. P. (January 2020). Multidisciplinary design and performance of the ONERA Hybrid Electric Distributed
Propulsion concept (DRAGON). AIAA Scitech 2020 Forum.
With hybrid-electric propulsion still in its infancy, the design space of potential architectures is quite open. For its exploration, agreeing on technology assumptions is key. Power densities and
efficiencies of electrical machines are just one example. An extensive set of these key-figures has been collected, reviewed and selected for the ongoing design effort. Since aircraft design is a highly
integrative and multi-faceted task, the key interfaces for communication exchange between the partners have been identified.
Given these prerequisites and the initial aircraft concepts, the team dedicated to electrical architecture is now designing its first conceptual electrical architectures for future SMRs and for regional
Baseline electrical architecture under examination
One of the key aspects when designing an electric architecture is to provide sufficient redundancy for the overall propulsion system to ensure safe and reliable operation. A first analysis has been
performed by the University of Strathclyde on a distributed propulsion architecture.
Reliability of distributed electrical propulsion architectures
While hybrid-electric flight shall be to the benefit of our environment, it shall not be to the detriment of passenger safety. Beyond pure safety aspects, reliability is also demanded for the everyday
cost-effective operation of modern aircraft. Unscheduled maintenance is to be avoided and the availability of the aircraft must remain high.Hence the University of Strathclyde has initiated a comprehensive
reliability analysis using dedicated stochastic models. For each component of the aircraft's electrical architecture, a corresponding failure rate is assumed and with the modelled interaction of these
components in the electric architecture, the reliability of the aircraft can be approximately forecasted for its entire operating lifetime. The current design proposal for an aircraft configuration for a
conservative short-medium range plane includes 24 Electric Propulsion Units (EPUs) that are distributed among its two wings. The figure below indicates the path of components that may lead up to the failure
of an individual EPU.
First results indicate that the probability of aggregate EPUs failures is low, in line with safety requirements, however individual failures of a single EPU might not be uncommon (being dominated by a failure
in the EPU drive-train itself). Thus, there is a need to further understand how an individual EPU failure can be handled in aircraft operations, the impact of their maintenance on the overall operations and
whether certain failure rates can be reduced as part of the EPU design. There is still significant potential for design optimization by better understanding the impact of a failing EPU.Although already
providing valuable insight, the analysis is still at an early stage: the impact of lightning strikes, short-circuit faults, potential common mode failures and the inclusion of the critical thermal management
system require further work and will impact the result of this preliminary analysis.
Figure 1 Cooling of the power generation (left) and the electric propulsion (right) units
A major technical challenge in electrically driven propulsion architectures is thermal management. While electric drives can be very efficient and have comparably low heat losses, they also demand much
lower operating temperatures. Finding a solution that adds little weight and causes little additional drag force but still works in all relevant environmental conditions is not an easy task.
Thermal Management of the SMR Architecture
Under NLR’s lead, the IMOTHEP partners develop a thermal architecture for the conservative short- and medium-range (SMR-CON) conceptual aircraft. The task consists of two parts: The cooling of the power
generation units and the cooling of the electric propulsion unit.
Cooling of the power generation unit
In the SMR-CON configuration, two separate gas turbines drive the generators for the entire electric power demand. The required fuel flow should be used for cooling as much as possible. An intermediate oil
flow transports the heat from the devices to the fuel. However, the fuel flow on its own is insufficient, even when combined with the air intake required for combustion. Various ways of increasing the airflow
are being investigated, such as an additional fan, a separate ram-air channel or the excessive use of engine bleed air.
Cooling of the electric propulsion unit
For each of the distributed electric propulsion units, a local cooling solution is required that uses the local airflow as a heat sink. The main design question here is whether to use direct air cooling or
liquid cooling. A local liquid cooling loop may enable higher power densities for the electric machine as well as a combined cooling of the motor and power electronics.
The overall goal of this technology stream is to study, design and integrated the components needed for generation and storage of electrical energy on the four aircraft platforms considered within IMOTHEP.
These activities are in close connection with the Integrated Vehicle Design, which provides the general energy and power level needed for the selected aircraft platforms. Basing on those numbers, the team
involved will provide, in close connection with the Integrated Vehicle Design:
dedicated studies related to emerging all-solid-state battery technologies suitable for aerospace applications and fuel cells
dedicated studies on the overall technology maturation needed for each platform
Two out of the four most promising hybrid-electric architectures currently under evaluation are presented below.
In the first semester of the activity, the main goal was to provide an overview of the technological state of the art and relative projection up to 2035 for both thermal engine and electrical machine. This
was shared with the teams working on integrated vehicle design and supported in this way the first conceptual design of the aircraft for regional and SMR segments.
Completing the initial designs of the energy generation systems for the different aircraft studied represents substantial progress in the project activities. Three different turbogenerators together with
an assisted turboshaft and a propulsion system based on fuel cells have been designed. The ongoing battery laboratory tests are reverting advances in cell configurations to define the battery performance
Technical progress and results
Dedicated energy generation systems have been designed to meet the power demand specifications of the four aircraft configurations defined within IMOTHEP. After the definition of the thermodynamic cycles, the
design and sizing of the main components in the gas generator flow path as well as of the power turbines have been defined. A preliminary positioning and integration of the dedicated electrical generators
designed has been specified considering mechanical interfaces and the working environment of the generators. An initial cross-section of the gas path and general dimensions of the overall systems are now
being defined. In addition to this, a dedicated propulsion system based on hydrogen fuel cells has been defined for one of the regional configurations. This last study shall serve as a benchmark for
comparison with the hybrid-electric alternative.Regarding battery technologies, coin cell lab tests for All-Solid-State Batteries (ASSB) are continuing with more than 130 coin cell samples prepared and
tested, delivering concrete findings on the exploration of the electrochemistry of the system with different configurations of Ni cathodes, hybrid electrolytes and Li metal anodes. Continuous data exchange is
feeding the calibration of battery models developed within IMOTHEP that are also providing alternative cases for the experimental design. The battery models developed are already being used in aircraft
studies within IMOTHEP.
Support the aircraft integration of the results and models created for the different propulsion systems and perform complementary studies on some of the modules developed in preparation for the next design
Preparation of battery coin cells for laboratory tests (Credit: AIT)
Activities related to “Energy Generation” have made considerable progress, notably in defining more detailed aspects of the propulsion systems. The project team has started to investigate the effects of
generator dynamics. Furthermore, the partners involved in the field of battery technology are in constant exchange on battery modelling with the partners involved in the aircraft design loops. Work is
also underway to revamp the fuel cell activities.
Technical progress and results
Recently, several aspects of the different turbogenerators to be evaluated have been further detailed, for example a more robust definition of the internal static structures and the locations of the
mechanical systems (such as bearings). This enabled progress in the initial phases of combined dynamic response studies on generator integration.
Discussions on broader aircraft integration issues have helped to better understand the management of thermal loads in the hybrid propulsion systems studied in the programme, as well as the alternatives to
different arrangements for the system, with some configuration trade studies still ongoing.
Following an update on the requirements and configuration of the platform after the initial design loop, the initial revision of the gas turbine system used in the Regional radical configuration has started.
The collaboration and coordination between the partners regarding the batteries and their integration in the investigated platforms on which they are used in the programme has been intensified.
A revamp of the activities involving the development of an alternative propulsion system for regional aircraft based on fuel cells has been conducted together with the partner in charge of the activity, with
revised milestones for the integration of the results to benchmark at aircraft level the positioning of these systems relative to the baseline hybrid-electric systems studied for regional aircraft.
Within the topic of “Energy Generation”, next steps will be
1.completion of configuration trade studies for alternatives to the thermal management system with the team from the design loops;
2.report on the results from the dynamic generator response activity;
3.development of the updated fuel cell system sizing for application in regional aircraft
4.preparation of the second design loop activities at program level.
This technology stream deals with the design of electric component that will compose the core of the propulsion system of the hybrid electric aircraft. The objective is to propose innovative solutions to match
the requirements for all the electric components that link energy generation or storage to mechanical power. Disruptive solutions like superconductivity will also be studied.
The main challenge is here to provide an optimised technical proposal that meets weight and performance required in order to reach the top leve laircraft requirements, as well as the project’s objective regarding
emissions reductions. In addition, the performed studies shall take into account the future evolutions of the technologies in order to provide evaluations consistent with the project timeline.
The team involved in this technology stream covers a wide expertise range (electrical machine, power electronics, EWIS, superconductivity, integration).
Illustration of Superconductivity phenomena
The first step was achieved with the evaluation of the expected electrical equipmens’t key characteristics and performances. Using this data, the teams working on the topics of Integrated Vehicle Design and
Electric Architecture can perform an initial system-level evaluation loop that refines the requirements for the next step.
Based on the four different aircraft configurations proposed in IMOTHEP, establishing the specification baselines for the electrical components of the powertrains started by collecting and
synthetizing outputs from the Conceptual Design Loop (“Loop 0”). Currently, these components are being evaluated before entering Design Loop 1.
Conceptual Design Loop: Preliminary performance assessment of electrical components
The work to establish the specifications for the electrical components started in mid-2020. The first step consisted in gathering and refining the top-level requirements coming from the conceptual design loop
studies of the regional and SMR aircraft configurations in both versions, conventional and radical. Based on the data relating to the four different aircraft configurations and bolstered by a workshop with
DLR, a set of specifications for each aircraft configuration has been established to support the technological assessment. The next step is the evaluation of the key parameters of each powertrain component,
with the Austrian Institute of Technology being responsible for the power electronics, the electrical motor studies being coordinated by the University of Nottingham and the wiring and interconnection by
SAFRAN. All data will be gathered to assess key parameters and performance of the electrical propulsion unit that meets the needs of each aircraft configuration. This task is driven by SAFRAN with the support
of Leonardo, the University of Strathclyde, ONERA and Politecnico di Bari. Current activities are focusing on the “conservative” short-medium range configuration (“DRAGON”, conceived by ONERA) and its
technical challenges, such as air-cooling for high power density machines and electronics, high-voltage harness etc. On the other hand, disruptive technological solutions for hybrid-electric propulsion, such
as superconductivity, are studied. This activity is led by the University of Lorraine, assisted by the University of Strathclyde and SAFRAN. The efforts are concentrated on the “radical” short-medium range
version, which is a blended wing body (BWB) configuration. This configuration needs the most electrical power and its interface seems to be the most appropriate for cryogenic tank integration. So, to start
with, the team will focus on identifying the key parameters of the superconductive powertrain and the technological enablers which shall be included in the Loop 2 aircraft configuration for superconductivity
integration (cooling system, cryogenics tank etc).
Electrical machine (pre-design)
DC/DC converter (pre-design)
The previous activities focused on the preliminary design of the electrical components of the Electric Propulsion Unit and the electrical architecture of the four aircraft concepts investigated under
IMOTHEP. After a phase of gathering and refining the requirements that emerged from the conceptual design loop, the performance assessment of the electrical components was carried out, considering
some sensitivity analyses.
Preliminary performance assessment of electrical components
Based on the latest results from the conceptual design loop, refinement and consistency of the requirements have been addressed for all four aircraft concepts and submitted to the aircraft concept leaders
for validation. In some workshops, the need to conduct sensitivity analyses for the scope of the electrical components was also pointed out to substantiate the assumptions and investigations at aircraft
The global performance assessment of the electrical components was carried out for both the Regional and SMR aircraft concepts in their radical and conventional versions.
The main components examined are the electric machine, the power electronics and the harnesses. In addition, an overall estimation of the performances at EPU level is evaluated.
For each concept, the key parameters assessed are the specific power, the efficiency and the envelope. A first set of sensitivity analyses was performed on the mechanical power level for the two Regional
concepts, a second set on the voltage level for the two SMR concepts, and a comparison between two cooling options (air or liquid) for both Regional and SMR.
Several sizing studies illustrated the differences in optimizing either specific power or efficiency. Finally, at the EPU level, two architectures are considered and assessed to answer the question of
whether a gearbox should be installed between the electrical machine and the propeller or fan.
Due to the amount of mechanical power involved in the SMR radical concept for the electric fans, superconductivity technology has also been investigated.At this stage, the perimeter focused only on the
power electronics and the electric machine. The preliminary design foresees a fully superconducting electric motor and power electronics at cryogenic temperature to save space and increase the specific
The next steps will be to
support the aircraft concepts for the integration of the preliminary results for the different propulsion systems and
perform complementary studies, considering the overall thermal management constraint, integration constraints and the safety results in preparation for the next design loop.
Roadmap Towards HEP
To elaborate the intended roadmap for HEP development, the results of the previous research work will be analysed, and additional specific studies will be performed to cover all aspects of the roadmap. Key
challenges to address include:
synthesising key enabling technologies and technology gaps;
identifying demonstration needs and proposing corresponding relevant demonstrations;
analysing the needs for tools and infrastructures;
identifying the needs for evolutions in regulations.
This cornerstone of the project involves seven industrial partners, research establishments from Europe and Russia, as well as EUROCONTROL and EASA.
A first stakeholder workshop will be organized on 11 November to reach out to the global community beyond project partners and gather all inputs for the elaboration of the European sector-wide roadmap. The
project will release a preliminary roadmap in early 2021 to pave the way to the new Horizon Europe framework programme with meaningful data. In particular, preliminary assessments of possible viable
configurations and specific technological paths for reaching the challenging objectives will feed the Clean Aviation Partnership and related SRIA.
This represents a unique opportunity to discuss, together with other EU projects related to HEP, possible synergies and gaps, both at aircraft configuration and technological level, to ensure a full coverage
of knowledge and address the challenge of developing HEP, by sharing and implementing together consistent and realistic roadmaps.
In order to support a full visibility and information sharing, a specific questionnaire was built and recently shared, helping the attendants in getting into the core of the project and contributing ideas to
The final and most important deliverable of IMOTHEP will be a sector-wide roadmap to 2035 for the maturation of hybrid-electric propulsion (HEP) in aviation. Work is in full swing, and conclusions will be
drawn later, but based on initial findings, the project will soon present a preliminary roadmap to serve as a basis for the numerous programmes currently being prepared in Europe.
Building on a first gap analysis and aircraft concepts
The IMOTHEP work started with a review of the state of the art of technologies for HEP and their projection to 2035 to determine the key performance assumptions for the initial design of the supporting
aircraft configuration. This review allowed to perform a gap analysis, providing information on technologies under consideration and the research needs to achieve the appropriate level of performance. This is
the cornerstone for elaborating the roadmap. The results from the first design loop of aircraft configuration, together with additional studies such as CENTRELINE* or NOVAIR also provided useful initial
insights on the system categories to be developed as well as on the development schedule.
*(recently completed – watch here our interview with Anaïs Haberman, BHL)
Reaching out to stakeholders
To complement this internal analysis, IMOTHEP organised its first stakeholder workshop in November 2020 to gather additional views and results from other ongoing projects and studies. These have fed into the
gap analysis and the preliminary roadmap which shall soon be released. Please stay tuned!
Beyond carrying out a detailed assessment of the potential of hybrid electric propulsion for reducing aircraft emissions, the ultimate goal of IMOTHEP is to build a comprehensive roadmap toward the
maturation of the technology.
Building such a roadmap requires considering multiple aspects, all playing a key role in developing the final product. First, these includes identifying the technology gaps and the research orientations to
bridge these gaps on the most sensitive components of the aircraft and hybrid system. These include also making sure that the right design tools and facilities are available to carry out the design. Finally,
these encompass anticipating the certification of the future system by making sure the right requirements and compliance means are in place. All these aspects are included in the roadmapping process of
Beginning of 2022, based on the progress achieved in the definition of the aircraft configuration and various subsystems, the project initiated two important activities with a view to elaborating the roadmap.
The first one is the analysis of the adequacy of current certification rules included in EASA CS-25FAR25 with hybrid electric technologies. IMOTHEP partners will examine which requirements and means of
compliance could not be applicable for HEP, and will propose solutions for adaptation. EASA will be involved through the review of the analysis and proposals. A second activity is the inventory of the
existing facilities for the development of HEP, which will support in a second step the identification of the need for dedicated facility development in Europe.
In parallel, based on the results of components definition studies, a preliminary gap analysis is being performed between the performance actually achieved by the design done by IMOTHEP partners and the
technology assumptions from the literature, which were used for aircraft configuration studies.