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The aspect ratio has a great effect on the aerodynamic characteristics. It is an important technique for the improvement of aerodynamic performance through drag reduction. The effect of aspect ratio on the airfoil performance is investigated about axially symmetric wings as a function of the angle of attack. Optimum design of lifting surface provides maximum possible lift force and minimum possible drag force. The wind tunnel used for the experiments is an open conduit and has a 1200x1200 mm2 x-section with a closed test chamber. Three different types of airfoil with different aspect ratios (AR 2, AR 1, and AR 0.5) are tested under the airflow speed of 37.5m/s. It is found that for the same wing area wing model of AR 2 reduces the strength of the vortices at the wingtip by reducing the tip vortex more effectively than any other wing models and as a result, the difference between the upper and lower surface pressures on wing model of AR 2 is comparatively higher than that of other wing models at various angles of attack. After analyzing the results, the wing model AR 2 is found to be the optimum