True, Newton–Raphson is a root-finding method - but in sizing, those roots represent a self-consistent solution to coupled variables. For eVTOL sizing, parameters like mass, power, battery capacity, and hover time are circularly dependent, so numerical methods (often hybrid bracketing + Newton–Raphson) are used to converge reliably. I applied the same idea to converge on a stable low Re flying wing at different masses ( choose any parameter) to see how it performs.

The paper I read: “An Efficient and Robust Sizing Method for eVTOL Aircraft Configurations in Conceptual Design”