# Turbulent flows over 6 series airfoils

6 Series Airfoils were developed to enhance the laminar flow region over the airfoil. But, the Reynolds number at which planes fly are high for the flow to be Laminar. Then what's point of introducing 6 series airfoils when laminar flow is not possible?

In reality the boundary layer will transition at some point before reaching the trailing edge, and become turbulent. In the case of the P-51, a shot down example was analyzed by H. Schlichting. He found that the transition point was at the 50% chord point for $$Re=4\cdot10^6$$ and as far forward as 20% of the chord for $$Re=7.5\cdot10^6$$, which suggests that the Mustangs performance had more to do with the polished finish and flush rivets of the wings than with the airfoil used.