The objective of this work is to conduct a stress analysis of an H-rotor vertical axis wind turbine (VAWT) blade under aerodynamic loads. The rotor blade is designed based on the maximum deflection and bending stresses at extreme loading conditions, specifically the maximum radial force acting on the blade. The impact of the tip speed ratio and blade pitch angle on the bending stress of the H-rotor VAWT is presented. Analytical beam theories are used to determine the maximum deformation and bending stress, which are then validated numerically using the finite element method (FEM) with ANSYS software. The blade is composed of S-2 fiberglass/Epoxy composite material. The stress analysis is performed on both a solid cross-section blade and a hollow blade with varying wall thickness. A comparison is made between the S-2 fiberglass/Epoxy and carbon fiber/Epoxy composites, revealing that carbon fiber composites induce greater deflection in the rotor blade compared to S-2 fiberglass blades. Additionally, it is concluded that the tip speed ratio directly affects both the bending stress and total deflection of the blade.