To get the ACTUAL induced drag, you multiply the Cdi by the wing area and the dynamic pressure.Well, if we go back to:
Cdi = Cl^2/(pi*aspect ratio* efficiency factor)
Evaluated at constant span and equal speed the formula for induced drag can be rearranged to:
Cdi = k*Cl^2*AR
The induced drag is proportional to the lift coefficient squared. Then for a given span, lift and speed the induced drag is linked to wing area due to the lift coefficient. And as the wing area shrink with increasing aspect ratio the necessary lift coefficient rises, but linear.
The sum up is that both high span loading and high wing loading is bad for induced drag. There is three possible ways to reduce induced drag:
- Increase wing span.
- Increase wing area.
- Fly faster.