## 3 Processing and Discussion of the Results  
Formula (1) was used to calculate the lift force coefficient:  
\[C_{y}=\frac{\Delta F_{y}}{\rho\cdot\frac{v^{2}}{2}\cdot S}; \tag{1}\]  
The drag coefficient was calculated using the following Formula (2):  
\[C_{x}=\frac{\Delta F_{x}}{\rho\cdot\frac{v^{2}}{2}\cdot S}; \tag{2}\]  
where \(\Delta F_{x}\) is the drag force, [N];  
\(\rho\) is the density of air, [kg/m\({}^{3}\)];  
\(v\) is the air flow rate, [m/s];  
\(S\) is the area of the midsection, [m\({}^{2}\)]. Figures 6 and 7 present the experimental data of drag and lift coefficients as a function of the angle of attack at different incoming air flow speeds for the asymmetrically shaped blade. The speed varied from 3 to 15 m/s. It can be seen from the graphs that the flow  
Figure 5: Model of a wind power installation with asymmetrically shaped blades. velocity does not significantly affect the dependence of drag and lift force on the angle of attack of the blade. The analysis of Figure 6 shows that the drag coefficient is minimal at a 0\({}^{\circ}\) angle of attack, as this corresponds to the most streamlined part of the blade. As the angle of attack increases to 60\({}^{\circ}\), the coefficient rises due to the increase in the blade's cross-sectional area. At an angle of attack of 150\({}^{\circ}\), the blade rotates with its \"hook\" facing the direction of the air flow, leading to the maximum drag coefficient. The coefficient then decreases until it  
Figure 6: Dependence of the drag coefficient of asymmetrically shaped blades on the angle of attack at different flow speeds. Figure 7: Dependence of the lift coefficient of asymmetrically shaped blades on the angle of attack at different flow speeds. reaches 210\({}^{\circ}\), where the blade's trailing edge covers the \"hook\" area, resulting in smoother air flow around the blade. Subsequently, the coefficient increases until it reaches 270\({}^{\circ}\), where the blade presents a large cross-section facing the oncoming flow. As the blade rotates to 330\({}^{\circ}\), the coefficient decreases to its final value. The analysis of Figure 7 shows that the lift coefficient has three peaks at angles of attack of 30\({}^{\circ}\), 180\({}^{\circ}\), and 300\({}^{\circ}\). The maximum value of the coefficient occurs at 180\({}^{\circ}\), which corresponds to the blade being fully turned toward the oncoming flow. In this position, as mentioned earlier, the blade's \"hook\" captures the air flow, leading to this result. The curve of the lift coefficient variation is explained by the blade's position relative to the oncoming flow. Figure 8 shows the experimental data on the effect of the angle of attack ranging from 0\({}^{\circ}\) to 20\({}^{\circ}\) on the lift and drag coefficients at an initial flow speed of 15 m/s. The study was conducted for comparative analysis with data from other authors on blades with symmetrical profiles. It is evident that as the angle of attack increases, the drag coefficient does not significantly increase. This is due to the increase in pressure distribution values on the lower surface of the blade. In turn, the lift coefficient increases as the angle of attack increases. This is also a result of the movement of the flow separation point towards the leading edge as the angle of attack increases. The NACA 0015 configuration is more commonly used in vertical-axial wind turbines of the Darrieus type due to its proven high performance at high TSR (ratio of rotor speed to wind speed) and high wind speeds. Figure 9 shows the aerodynamic characteristics of the NACA 0015 configuration. Lift coefficients increase with the angle of attack, and this behavior is consistent across angles due to the symmetrical shape. The drag coefficient also increases with the angle of attack. Subsequently, experimental data from a three-blade model with asymmetrically shaped blades were presented. Figure 8: Dependence of the lift and drag coefficients at different angles of attack for the blades of an asymmetrical shape at a wind speed of 15 m/s.