text: Q:
  
  What is wing inductance?
  
  I am currently trying to understand the ground roll and climbing stage of normal aircraft.
  I came across this formula which is an expression of the airplanes drag:
  $X_a = c_{{x}_a} S \frac{\rho V^2}{2}$
  where: $ c_{{x}_a} = c_{x0} + A c^2_{x_{a}}$
  
  S: wing area
  $\rho$: air density
  V: velocity
  $c_{x0}$: drag coefficient when the lifting force = 0
  $c_{x}$: drag coefficient
  
  A is said to be the wing inductance. Could somebody explain what is meant by wing inductance?
  
  A:
  
  $$A = \frac{1}{\pi \cdot e \cdot AR}$$
  where
  $\pi = 3.14159....$, $e$ is the Oswald efficiency factor, and $AR$ is aspect ratio of the wing.  
  
  