The DEFENDER Project is part of the European research and development program Clean Sky 2, which was created to initiate public-private partnerships between the European Commission and the aeronautics industry with the aim of creating innovative aircraft in terms of environmental impact, throughout their life cycle. The consortium, led by Leonardo Helicopters and coordinated by the Politecnico di Torino, is composed exclusively of Italian partners, namely the Italian Aerospace Research Center (CIRA), AERO SEKUR, and STEP SUD MARE. The DEFENDER project is geared toward the study of an innovative fuel storage system to be integrated into the technology demonstrator of a next-generation tilt rotor for civil use produced by Leonardo Helicopters.