# How to calculate lift and drag coeffecients for VTOL aircraft in the takeoff stage?

How would I calculate CL and CD for a VTOL aircraft while it is in it's takeoff/landing stage?

The particular aircraft is a fixed wing/quadcopter hybrid so I know that I can treat this as a thin rectangular plate problem. However, because the aircraft takes off vertically, I do not understand what formulas to use to calculate these coefficients.

If I use CL=2$$\pi\alpha$$, where $$\alpha$$=$$\pi$$/2, then I end up with CL=9.87, which just doesn't make sense.