Against roll instability, should I add more dihedral/a high wing?
I'm trying to build an RC plane that can handle windy conditions. For that I want extraordinary aerodynamic stability. For longitudinal static stability, I make my planes quite nose-heavy, and compensate for that with a greater tail downforce. That works. What doesn't work is lateral stability/roll stability. In theory, if a gust rolls my airplane, I will have a sideslip. Due to a high-wing configuration, and a dihedral angle, I will have a rolling moment that will counteract the original roll angle. Image from avstop.com, modified
So I made my plane attempts have great dihedral/polihedral angles, and a really high wing with a solid surface underneath to further help counteract any rolling.
Any time I went crazy on dihedral and high wings, my planes kept crashing agressively due to very sudden and very powerful side/back flips. At first I didn't understand, as these features should've made my plane almost un-rollable.
However, what I suspect is that these features had the opposite effect. Correct me if I'm wrong, but looking a the first diagram, what I see is that when a plane flying at level flight encounters a sideways gust, it will also make the plane agressively roll over, just as if the sideways gust was from a roll induced sideslip.
Is this a correct assessment? Did these roll stability features make my planes roll around uncontrollably?
Is there a way to have my plane react normally to a sideways gust while having static roll stability? Do I need way bigger vertical stabilizers for these dihedral values?