Automotive parachute equivalency
 

This is for the truly twisted!
And for simplicity, I'm basing the following on the old-timey, standard military parachute I jumped with in the Air Force. Cd 1.35.
If you know your Cd and Af, then you know your CdA.
To get the diameter of a parachute of equivalent drag as your vehicle, use:
[ ( square-root of ( CdA / 1.35 ) / pi ) X 2 ] = diameter :p

So if I ever find myself vehicle transport plane that is catastrophically failing, I should hop into the hummer for the ride down.

'HUMMER'
 

hopefully, they'll have the H-1. Cd 0.70.
try to get it to fall, tail first, with all the doors open.
'Gravity, it's not just a good idea, it's the law! ' ( as seen inside a HOOTER's restaurant in Lewisville, Texas )