This thesis presents the development and validation of a high-fidelity flight simulation model for a multipurpose helicopter, implemented within the Matlab/Simulink environment. While the immediate focus is on validating the model against reference data provided by commercial simulation software, the primary objective of this work is to establish a repeatable validation methodology. This workflow is designed to be future-proof, allowing for the seamless integration of experimental flight data to update and refine the model as they become available. The core of this methodology is applied to the aerodynamic modeling of the shrouded tail rotor. Specifically, the study optimizes the Pitt-Peters inflow relations to address discrepancies observed in the baseline model.