RE: Elevator SNAPROLL
kq, any model that has a highly tapered wing with a high enough wingloading will be prone to that when least expected or at the worst times...all the first planes I ever designed were very good at snapping until I finally got a clue.
If the wingloading is right, the tendency is dampered, even eliminated. My goal for a good handling model is to be able to use the elevator at will to make the model go up and down, not to make it stall to one side or the other. A good model in my opinion needs both rudder and elevator commanded to generate a snap at flying speeds.
Some "built in" tendencies that full scale planes have don't scale down very well or lend themselves well to good handling models.
There are a lot of great examples of 3D models of the full scale aerobats that have bumped the wing area way up past "scale" and are more forgiving than your average trainer. These planes will fly circles around their more scale like counterparts and avoid involvement in those messy garbage bag rituals better, too.