• NACA 64A010-PT (Fig. 12.64)
Compared to the two symmetric airfoils discussed so far (J5012, NACA 0009), the 10% thick NACA 64A010 is the worst for low-Rn applications. The shape of the polar, with the large decrease in drag just before the stall, is caused by a long run of a favorable pressure gradient followed by a steep recovery region. In the design of this airfoil, the intention was to achieve long runs of laminar flow for low drag. While this design approach works for high Rn’s, the same line of reasoning cannot be applied at low Rn’s.
Figure 12.65 shows the lift characteristics for J£n’s of 100k, 80k and 60k. At 60k the presence of a long bubble can be inferred from the nonlinearities around zero angle of attack. It is interesting that for i2n’s of 100k and 80k the nonlinearities almost vanish. This does not mean that the separation has vanished; instead, the separation on the upper and lower surfaces apparently have the combined effect of cancelling each other out.
Also see: NACA 0009, SD8020, J5012 Digitizer plot: Fig. 10.24 Polar plot: Fig. 12.64 Lift plot: Fig. 12.65
Thickness: 10.00% Camber: 0.00%