Comparison of the Aerodynamic Characteristics between NACA0012 and NACA4412 Helicopter Rotor Airfoils under Severe Convective Conditions

Severe convective weather often accompanies with the high turbulence intensity and the vertical gust interference, which can strongly affect helicopter rotors during low-altitude flight and can easily cause dynamic stall, and threaten flight safety. This paper investigates two airfoils with the same geometric thickness: the symmetric airfoil (which is NACA0012) and the cambered airfoil (which is NACA4412). This paper compares them using published wind-tunnel experimental data and published CFD studies. The lift force, drag force, pitching moment, and flow-separation characteristics of the two airfoils under the severe convective disturbances are compared to see how geometric parameters can influence the disturbance resistance of rotor airfoils. The results show that NACA4412 airfoil has better static lift performance and it is able to generate greater lift at lower speeds, whereas the symmetric NACA0012 airfoil has smaller load fluctuations under the gust disturbances, better stall resistance, and better operating stability under adverse severe-convective conditions.