Periodic Reporting for period 2 - MAHEPA (Modular Approach to Hybrid Electric Propulsion Architecture)
Reporting period: 2018-11-01 to 2020-04-30
Air transport is growing yearly over 4% creating new jobs, new mobility opportunities for citizens and new freight transport routes. The environmental costs however, cannot be overlooked. Although newer, more efficient engines equip recently built aircraft, CO2 and NOx emissions from the aviation sector are a non-negligible contributor of overall transport emissions. Acoustic pollution represents also a point of concern for communities surrounding airports, to the point that small General Aviation airfields face weekend closures when nearby residential suburbs are not separated by a buffer zone. To mitigate aviation emissions, electric propulsion represents a key revolutionary technology. Electric aircraft are quieter because there is no combustion engine noise and the propellers can spin at lower frequencies. When operated on fuel cells or battery power only, they represent truly a zero-emission vehicle for the nearby communities.
The objectives of the MAHEPA project are to develop innovative and lightweight hybrid-electric powertrain components and characterize their performance in flight to assess advantages and drawbacks in a rigorous way. Two variants of hybrid-electric propulsion architecture will be tested in flight: the first charges the batteries using a generator connected to a four-stroke internal combustion engine (ICE), while the second variant produces electric power by converting hydrogen in a fuel cell (FC). Each of the variants is installed in a dedicated four-seat test aircraft and both single-propeller airplanes use the electric motors developed in the project. Besides the component development and testing, another important project objective is the framing of a broader picture by preliminary studying new concepts for 19- and 70-seat hybrid-electric aircraft and their impact on infrastructure, regulations and overall emission reduction in an attempt to provide a holistic view of the revolution hybrid-electric aviation will bring to our society.
In parallel to the novel hardware and software development, several studies were started to frame a broader approach to hybrid-electric aviation. Assuming regional transportation can benefit from a 19-passenger and a 70-passenger hybrid-electric aircraft, research activities started to explore the infrastructure costs and burdens considering both the fast recharge and the battery swap case. Innovative aircraft design tools were developed to assess the economical utility and flight performance of new hybrid-electric 19- and 70-seater aircraft. In particular, tools for sizing novel hybrid-electric propulsion systems and hybrid-electric aircraft at conceptual level were developed and validated using experimental data from literature. In the next reporting period, these tools will be used to develop two design concepts, which will form the reference aircraft to estimate the environmental benefits and economic impact on society of hybrid-electric aviation.
In the second period all systems’ designs have been completed and components have been manufactured and tested. The two aircraft prototypes have been manufactured and are ready to begin ground testing.
The university partners continued with the work on the optimization of the power management and on scalability and market studies. Interesting results have been achieved about the modelling of transport demand and new route scenarios.
Nevertheless, there are delays in the project, mainly in the integration of the components. In fact, the ICE-hybrid powertrain ground testing phase is suffering a total delay of almost one year; this is mainly due to the high complexity of the system, which needed a longer development time than what was predicted. Moreover, during the qualification testing of the electric motor, the freewheel broke two times causing an additional delay. Motor and inverters have been completed one year later than what was predicted in the Grant Agreement.
Last but not least, the COVID-19 pandemic slowed the project pace since for many partners it was not possible to continue the ground testing.
These delays will have an impact on the project, especially in terms of flight test data analysis. However, the consortium is well aware of this and is preparing corrective actions to be taken in the third reporting period.