Exploring aerodynamic characteristics of cambered fore-and-aft symmetrical airfoil at low speed

An unmanned aerial vehicle (UAV) with rotational wings is popular because it can take off and land vertically and cruise at high speed. The airfoil with rotational wings is different from the airfoil with fixed wings. The difference is significant for the design of the airfoil with rotational wings and for the study of its aerodynamic characteristics. Therefore, we design a cambered (upper surface convex and lower surface concave/USCLSC) and fore-and-aft symmetrical airfoils for the UAV with rotational wings. The subsonic numerical calculation is performed to determine the airfoil with the optimal lift drag ratio, whose maximum camber is 10%, and maximum thickness is 12%. To verify the accuracy of the numerical calculation, we conduct wind tunnel tests under three low speed work conditions: V=20 m/s, 30 m/s and 40 m/s. The test results, given in Figs.3 through 9, and their analysis show preliminarily that the lift coefficient and drag coefficient obtained with the numerical calculation agree well with those obtained with the test results, which indicate that the airfoil we thus designed has good aerodynamic characteristics and is suitable for a rotational wing.