In this research, the performance of a horizontal axis wind turbine (HAWT) is investigated, considering the cone angle effects. In a HAWT with an ordinary pattern, all blades are located in one plate and the cone angle of the plate is zero. In the design of HAWTs, to prevent contact between the blades and the turbine’s tower and considering the aero elasticity effects, the blades are installed on the shaft of the rotor using a cone angle, which has effects on the turbine’s performance. We investigated the aerodynamic performance of the HAWT according to cone angle deviations, numerically. With a change in the blade’s plate pattern, a cone-shaped volume is created. In this condition, the projected blade’s length gets smaller and the blade’s sections (vertical to the wind) become larger. The geometry of these sections was obtained with AutoCAD software. The performance of the turbine was analysed with Qblade software, and the results compared with each other. The output results of Qblade for the situation, in which the cone angle is considered, equal to the projected blade’s length and the new sections for the projected airfoils within the zero cone angle investigated and compared. This research was carried out for two conditions: a blade with a constant chord and a blade with different chords through the length of the blade. The creation of the cone angle may be suggested as one approach for controlling the wind turbine.