Are stabilators effective for controlling roll and pitch for a plane with a high aspect ratio wing (i.e sailplane)? This question comes from an argument that my friend and I won't let go. My contention is that if the horizontal stabilizers are of adequate size and aspect ratio that their moment arm would be large enough to induce a lateral roll. He says no chance, to induce that kind of rolling moment, the tail would not be able to also produce the downforce necessary to keep the plane flying straight and level. Help!