FUTPRINT50

Recently, the new Green Deal policy initiative was presented by the European Union. The EU aims to achieve a sustainable future and be the first climate-neutral continent by 2050. It targets all of the continent’s industries, meaning aviation must contribute to these changes as well. By employing a systems engineering approach, this high-level task can be split into different levels to get from the vision to the relevant system or product itself. Part of this iterative process involves the aircraft requirements, which make the goals more achievable on the system level and allow validation of whether the designed systems fulfill these requirements. Within this work, the top-level aircraft requirements (TLARs) for a hybrid-electric regional aircraft for up to 50 passengers are presented. Apart from performance requirements, other requirements, like environmental ones, are also included. To check whether these requirements are fulfilled, different reference missions were defined which challenge various extremes within the requirements. Furthermore, figures of merit are established, providing a way of validating and comparing different aircraft designs. The modular structure of these aircraft designs ensures the possibility of evaluating different architectures and adapting these figures if necessary. Moreover, different criteria can be accounted for, or their calculation methods or weighting can be changed.

Electric and Hybrid-Electric Aircraft (HEA) propulsion system designs shall bring challenges at aircraft and systems level, mainly in propulsion, electric and thermal management systems (TMS). The electrification of the propulsion system relies on large and high-power electrical equipment (e.g., electrical motors, converters, power electronics, batteries, and others) that dissipate heat at a rate at least one order of magnitude higher than conventional propulsion aircraft systems. As a result, high impacts on weight, drag and power consumption of the TMS/cooling systems at the aircraft level are expected. This paper proposes potential technologies to perform the thermal management of future electric and HEA, in the context of FUTPRINT50 project. For each technology, relevant aspects such as its integration to aircraft, safety, operational and maintenance impacts, certification, technologies readiness level (TRL) and the latest research works are analysed. A quantitative comparison of the several technologies is also proposed considering weight, volume, electric power consumption, pneumatic air flow and cooling air flow per cooling effect. Lastly, we present a set of potential TMS architectures for HEA.

A hybrid-electric regional aircraft for 50 passengers has challenges in technology, operation and future regulations similar to larger class aircraft. It is thus at the right spot to drive technology, regulations and operational developments in order to accelerate cleaner flight technologies based on propulsion electrification. The FutPrInt50 team set up Top-Level Aircraft Requirements that aim to be a reference foundation for the development of specific topics handled in this H2020 project but also drive the open collaboration model adopted by FutPrInt50. In this paper the development of the mission statement will be explained for a hybrid-electric 50 passenger regional aircraft, which builds the framework for the Top-Level Aircraft Requirements. To further support development from these requirements, a mission scenario will be presented for this class of aircraft.

In the course of the aircraft design process for a hybrid-electric aircraft, a number of configuration alternatives have to be assessed. In addition, novel propulsion concepts have to be compared to a conventional reference aircraft. These comparisons are carried out by means of suitable figures of merit, adapted to a reference mission. This work will give insight into the process of identifying suitable figures of merit for a 50-seat hybrid-electric regional aircraft, which was carried out in the Horizon 2020 project FutPrInt50. Coming from a thorough perspective, a down-selection leads to a graspable number of parameters which are categorized in regard to the environment, to the airline desirability, and to the introduction of hybrid-electric aircraft. Those figures of merit, like emissions and operating costs, are gathered in an objective function which can support an overall evaluation of the aircraft design. This offers a detailed, yet transparent assessment of the various designs.