The present research investigates the flight dynamics modeling of a new class of Long-Range Guided Projectiles (LRGP), studied at the Institut Franco-Allemand de recherches de Saint-Louis (ISL), and the development of a full 6-DoF nonlinear simulator. The LRGP concept consists of a fin-stabilized projectile, having four rear fins and two horizontal front canards. The canards are mounted in a non-coplanar fashion with respect to the rear fins, in a so-called 'X' configuration. During the simulator design, the equations of motion describing the translational and attitude dynamics & kinematics of the projectile are first illustrated. A major contribution relies on the derivation of a new aerodynamic model based on an extensive regression analysis of the available data. Two full Computational Fluid Dynamics (CFD) campaigns were performed, dealing first with the static characterization of the projectile body, and later more specifically, with the contribution of the canard deflections. For the static characterization of the body, we propose two different regression approaches: a standard Simple Linear Regression based on polynomial fitting, and a more advanced Multivariable Regression. These approaches are individually investigated, and then cross-compared to assess which one provides with the most reliable results. A second regression analysis is developed in order to model the aerodynamic control contributions given by the canards deflections. The linearity of the canard response is investigated as a function of the Mach variation and of the selection of the regression model complexity. Finally, some trajectory simulations of the overall nonlinear simulator are proposed, as a model design validation.