Racing Stabs
A stab airfoil is really a series of different airfoils, one for each angular position of the elevator. Stabs generally operate at very low lift coefficients and there is usually a big stall margin. The drag characteristics depend on the smoothness of the hinge line on the convex side when the elevator is off center. For most thin sections and elevator deflections of up to about 3 or 4 degrees the drag remains low because the flow remains attached. Beyond that small deflection, the drag increases abruptly as the flow seperates and continues increasing with increased deflection as the turbulent wake thickens. For speed models, it is important to keep the pitch stability close to neutral so that the horizontal tail load and elevator deflections are minimized so that horizontal tail drag is minimized during the high speed mode of flight. For take off and landing more elevator deflection can be tolerated.