94
P. Liu
Fig. 2.26 Evolution of airfoil
and proposed four-digit airfoil family and five-digit airfoil family of NACA,
as shown in Fig. 2.26. After a systematic study of the airfoil, they found that:
(1) if the airfoil is not too thick, the thickness and curvature effects of the
airfoil can be considered separately; (2) if a good airfoil obtained from experience in various countries is straightened, that is to say, it is changed into a
symmetrical airfoil and converted into the same relative thickness, its thickness distribution almost coincides with each other. Therefore, it is proposed
that the thickness distribution of NACA airfoil family is the best one of the
time (as shown in Fig. 2.27).
Fig. 2.27 Velocity and pressure distribution on the upper and lower surfaces of
NACA2412 airfoil
P. Liu
Fig. 2.26 Evolution of airfoil
and proposed four-digit airfoil family and five-digit airfoil family of NACA,
as shown in Fig. 2.26. After a systematic study of the airfoil, they found that:
(1) if the airfoil is not too thick, the thickness and curvature effects of the
airfoil can be considered separately; (2) if a good airfoil obtained from experience in various countries is straightened, that is to say, it is changed into a
symmetrical airfoil and converted into the same relative thickness, its thickness distribution almost coincides with each other. Therefore, it is proposed
that the thickness distribution of NACA airfoil family is the best one of the
time (as shown in Fig. 2.27).
Fig. 2.27 Velocity and pressure distribution on the upper and lower surfaces of
NACA2412 airfoil