After putting more time on the Cub, have found that the elevator control is the one to make the bird expose its twisted nasty nature. This Cub can fly knife edge and I can slip it all the way to landing. So it can fly in an uncoordinated fashion no problem as long as the angle-of-attack on the wing is low. But..... Just pull back on elevator stick during a slip at altitude and it is snap roll time. My other models are more forgiving, but this J3 has taught me a new criteria for checking out a model's stability.