Chapter 10 Civil Aircraft Vehicle Design A. Sgueglia, S. Dubreuil (), and N. Bartoli e-mail: sylvain.dubreuil@onera.fr 10.1 Introduction In the recent years, aviation is facing with the increasing of fuel price and flights, and the impact is estimated to grow more and more in next years without any action (Collier and Wahls 2016). To reduce its environmental footprint, engineers are trying to design more efficient aircraft, with engines less consuming. However, the classical aircraft’s tube and wing configuration has been developed over half a century, and it still offers small potential gain. A breakthrough in aircraft design is then needed to drastically reduce the problem. Innovation can be brought at aircraft’s configuration level (considering different architecture than the tube and wing, like the Blended Wing Body (Liebeck 2004; Sgueglia et al. 2018b), see Chapter 11 for an example of Blended Wing Body design problem) or at propulsive level, introducing a partial or total electrification in the propulsive chain (Friedrich and Robertson 2015). In any case, the problem of designing an unconventional aircraft is more complex than the classical one, due to the strong coupling between disciplines, as shown by different authors, for instance by Brelje and Martins (2018). For example, in an electric architecture, thermal aspects play a key role due to the power dissipated by electrical components, or the distributed propulsion fans change the flux on the wing, and the overall aerodynamics performance is then modified (aeropropulsive effects). This chapter presents an unconventional large passenger aircraft, with a hybrid distributed propulsion, considering an entry into service (EIS) in 2035. The concept has been proposed by Sgueglia et al. (2018a). The aircraft is designed thanks to FAST (Fixed−wing Aircraft Sizing Tool, (Schmollgruber et al. 2017)), a multidisciplinary code that takes into account all key disciplines and interactions between them. Since we are dealing with EIS2035, hypotheses on the technological level for that horizon are formulated. In the literature, there are multiple assumptions, an uncertainty-based study is presented here to cover all the possible values in the 2035 perspectives. Multidisciplinary analysis formulations © Springer Nature Switzerland AG 2020 L. Brevault et al., Aerospace System Analysis and Optimization in Uncertainty, Springer Optimization and Its Applications 156, https://doi.org/10.1007/978-3-030-39126-3_10 361