Weight Estimation of Novel Aircraft Configurations in Early Design Phase

Initial weight estimation from Top Level Aircraft Requirements (TLAR) is a critical first step in aircraft design, yet existing empirical methods are inadequate for novel configurations such as those using Liquid Hydrogen (LH2) or Sustainable Aviation Fuels (SAF). This paper presents a hybrid methodology for top-level weight estimation of such unconventional aircraft. The approach is based on modifying a conventional baseline aircraft, integrating a new statistical model with component-specific weight estimations. A multivariate regression model to estimate the empty weight fraction (W_e/W₀) was developed from a dataset of 44 conventional aircraft, yielding an R-squared value of 0.833. This statistical model was integrated with physics-based models for novel components, including cryogenic fuel tanks and fuel systems. The methodology accounts for iterative changes to fuselage structure and parasitic drag. Four configurations were analyzed: fuel types being Jet A1, SAF, LH2 with aft-fuselage tanks, and LH2 with under-wing podded tanks. The results demonstrate that while LH2 configurations introduce weight penalties for tanks and systems, these are significantly offset by a reduction in fuel weight, resulting in a final Maximum Takeoff Weight (MTOW) comparable to or lower than the conventional baseline. The modular nature of this methodology makes it a viable tool for exploring the design space in early-stage conceptual design.