John - Amen

Wes - Agreed if there is zero beta. I think what we generally see in models is the airplane gets loose in yaw on the slow speed landing approaches. That encourages the asymmetry which causes the stall. Most of the tip stalls that happen in this manner end up with the airplane in the dirt. It's hardly ever seen at altitude and normal flying speeds.

Are you sure the tip never stalls? Certainly at sufficient angle of attack the whole wing will separate which by definition is a stall. Your separation at the root and middle sections are for the perfect 0 beta case. Dick's little foamys (and mine when I can get it right) go through a trasistion phase that indicates this.

I was thinking about what is needed to cause the roll after stall last night. It occurred to me that it takes very little aileron to roll a model (non 3D maneuvers). It doesn't take a lot of wing separation in an asymmetrical mode to get a nice roll into the ground.