Numerical investigations were carried out to implement trapezoidal MVGs on the 4R-UAV wing. 4R-UAV is a project funded by the Latvian Council of Science with the goal to create an innovative, aerodynamically improved, and environmentally friendly UAV. Two different types of trapezoidal (straight-edge and rounded-edge) MVGs based on their geometric configuration were investigated numerically. The aerodynamic performance of both MVG geometries was evaluated at 15%, 19%, and 25% chord locations. As a whole, straight-edge trapezoidal MVGs illustrated enhanced aerodynamic characteristics with improved lift (nearly 5%), sustained drag (up to 4.5%), delayed stall, and improved aerodynamic quality during all flight modes. The study also found that 19% chord location is the most appropriate for the implementation of trapezoidal straight-edge MVGs. Straightedge trapezoidal MVGs also demonstrated attached flow and symmetric velocity distribution over the wing surface, while other designs had already stalled. The study suggests that straight-edge trapezoidal MVGs can be implemented for the 4R-UAV wings due to the enhanced aerodynamic performance.