Flat plate airfoil polars for stall

[PaulPounds]

Everyone knows about flat plate airfoils, but no one would ever use one, right? Well, I've got a very thin airfoil rotor operating at high AoA, so I reckon it's performance can't be far off a flat plate at and past stall.

Can anyone direct me to accurate polars of flat plate behaviour at stall AoA and beyond?

-Paul