Rotorcraft Fuselage Weight Assessment in Early Design Stages

Like the design of fixed-wing aircraft the design of rotorcraft is generally divided into the three consecutive phases of conceptual, preliminary and detailed design. During each phase the acquired results in turn serve as input for new calculations, thus increasing the detail level and information about the new concept while uncertainties about the new design are reduced. An important aspect of the overall design process is the weight estimation in early design stages. The weight of the rotorcraft drives the design of many important components, such as the rotor(s), the propulsion system and, therefore, the required fuel. The fuselage is considered as the central structural part since it connects all other components to each other and serves as protection of the occupants but in the past it often turned out to also be the heaviest part of all rotorcraft components. This paper shows an approach to estimate rotorcraft component weights using statistical methods based on existing rotorcraft but also an approach to use finite element methods that determine the structural airframe weight based on mission profiles respectively bearable load cases.