Question

The NACA LS (1) – 04XX airfoils when compared to NACA airfoils with same thickness had higher L/D ratios. For a lift coefficient of 1.0, what was this increase approximately in percentage?

(a) 80%

(b) 20%

(c) 50%

(d) Less than 10%

This question was posed to me in unit test.

I need to ask this question from Modern Low Speed Airfoils in portion Incompressible Flow over Airfoils of Aerodynamics

Answer 1

The correct answer is (c) 50%

For explanation: The lift coefficient of 1 is vital for the aviation sector. The new low-speed airfoils developed had higher L/D ratios. For a lift coefficient equal to 1, the increase was about 50%.