vana WHAT?  gaon? eh?
Try  0.49 or 0,49 in Italia and you'll be PDC for all practical purposes.
What is it you are trying to calculate?  Thrust vs Velocity + Acceleration
or?

The equations are QED and well known the measure of the frontal area is
easily approximated.  A coast down measurement of deceleration will give you
the necessaries for all the rest.

p