Rapid Fuselage and Cabin Sizing Method for Commercial Transport Aircraft Conceptual Design

Fuselage and cabin sizing are critical to clean-sheet aircraft design and existing aircraft retrofit studies due to their impact on aircraft weight and aerodynamic performance. Existing sizing methods from conceptual design textbooks and aircraft sizing tools rely heavily on historical data of legacy aircraft and therefore lack the accuracy and flexibility to support parametric fuselage and cabin sizing for modern tube-and-wing aircraft. This paper addresses this functionality gap by proposing two new methods that better capture the main features of modern aircraft fuselage and cabin design: one performs detailed sizing and buildup for all major cabin elements, and another directly predicts fuselage and cabin dimensions based on existing aircraft data without detailed component sizing. Both methods are tested and validated across a large set of aircraft, demonstrating improved accuracy in predicting cabin dimensions and sizing the fuselage over preceding methods. Showing substantial improvement over current sizing practices, the proposed methods are ready for integration into existing conceptual design frameworks as a result of an intentional design choice to produce the same output format from the same minimal set of inputs.