Helicopter vibrations significantly influence structural integrity, operational reliability, and crew comfort. This study focuses on the unmanned helicopter Skyspotter 152, presenting a methodology for analyzing operational vibrations and developing its digital twin. Direct frame-mounted measurements were performed to capture both low-frequency inertial and high-frequency vibration components, overcoming the limitations of autopilot data. The acquired acceleration profiles were used to define realistic loading conditions for a high-fidelity finite element model (FEM) of the helicopter structure. Subsequently, a reduced-order model (ROM) was generated using Twin Builder, enabling efficient real-time prediction of structural responses. The resulting digital twin framework, currently operating in an offline mode, lays the foundation for future real-time applications, including predictive maintenance and flight control enhancement. This integrated approach demonstrates the importance of accurate vibration characterization and advanced modeling techniques for the development of reliable digital twins in aviation.