Thinking about this some more, if we assume that the elevons move up and down by the same amount, (i.e. no differential) to prevent the pitch altereing when rolling will not the downgoing elevon counteract the rudder effect of the upgoing one?View attachment 22754Picture an elevon straight up. It becomes more and more like a rudder as the hinge angle is increased as in the lower wing. When the hinge angle increase is combined with a tip plate or fixed rudder and a few degrees of dihedral it turns more like you're using elevator and rudder. It has a very controllable mush as well. The drawback is that it washes out the inboard section of the wing more than the outer and likely causes greater drag when the elevon is out of it's normal position. I gave up on flying wings. They look beautiful, but they're never as efficient as a conventional planform.