This thesis investigates the combined effects of spoiler and split flap deflections on the Flying V aircraft under sideslip conditions. Previous studies examined these surfaces independently under symmetric conditions on an earlier design. To assess their combined performance on the updated Flying V design in sideslip, a full-span wind tunnel model was tested in the TU Delft Low Turbulence Tunnel (LTT) using a Modern Design of Experiments (MDOE) approach. Response Surface Methodology (RSM) was applied to model the aerodynamic forces and moments as functions of surface deflection and model orientation. Both the flaps and spoilers were found to underperform relative to previous results. Statistically significant interactions were identified between flap deflections and inboard/outboard spoiler panels across multiple forces and moments, and undesired lift generation was observed for low spoiler deflections. These findings highlight complex interactions between surfaces in yawed flight and inform future configuration design for the Flying V.