Wing design and powertrain integration for a distributed electric propulsion demonstrator aircraft

This paper presents the powertrain integration as well as the structural wing design of an unmanned demonstrator. Different powertrain integration and structural concepts were qualitatively evaluated and compared to identify the most suitable approach. More precisely, different concepts for the placement of the batteries and the inverters were compared. Additionally, various structural concepts for the wing design were analyzed. Load-bearing connections between the powertrain components and the necessary wing structure to withstand the expected loads during flight testing were designed. All structural elements were iteratively designed to reduce weight while ensuring strength and stability. The structural integrity was verified with suitable finite element simulations. Furthermore, the resulting wing design for the eight-engine distributed electric propulsion concept was compared to a reference design. For this comparison, a second wing, with the same wing area, but only two electric engines with the same propulsive power was developed. Although, the wing structure of the distributed electric propulsion version is 9% lighter, compared to the reference wing design, the overall mass of distributed electric propulsion wing design including all structural components as well as the powertrain components is 14% higher compared to the reference twin engine design. The reason is the increased number of parts for the mounting structure of the additional engines. Finally, the differences for the scaled wing designs were compared with results from full-scale aircraft design studies, to assess the scalability of the results from scaled unmanned designs to full-scale aircraft concepts.