Weight Estimation and Architecture Definition of Fuel Systems for Aircraft Conceptual Design

The design of hybrid-electric, distributed-electric, and unconventional aircraft requires improving existing conceptual design methods. In particular, hybrid-electric aircraft require more integration between the traditional propulsion system and the aircraft systems (i.e., the electrical power system, flight control systems, and fuel system). Traditional conceptual design methods for aircraft systems rely on statistical data using empirical weight estimation. The shift to hybrid-electric aircraft will particularly impact the fuel system; for example, less traditional fuel storage being required but maintaining the same critical components. As state-of-the-art weight estimation methods use fuel capacity as the key parameter, they cannot be applied to hybrid-electric aircraft studies. This paper proposes two new methods: an updated empirical method tailored explicitly to commuter and regional aircraft and a more generic architecture-based approach. This architecture-based approach estimates the fuel system weight based on individual subsystems and major components from information available in conceptual design, using manufacturer data and physical relationships at the subsystem and component level. The validation and the application to a hybrid-electric regional aircraft case study are presented to illustrate the capability of the new method. In summary, the architecture-based approach for the fuel system enables more detailed subsystem analysis as required in the next generation of multidisciplinary optimization frameworks, for the analysis of certifiability, safety, reliability, and thermal analyses.