The sole reason for employing "park bench" ailerons is to permit the use of longer flaps. Park bench ailerons are much less effective than normal ailerons, since they act, largely, as little independent surfaces, very much like the ailerons that were mounted between the wings on some very early biplanes. A trailing edge aileron acts in concert with the wing surface ahead of it, changing the lift coefficient of the entire surface, and thus producing vastly higher rolling moments in relation to its surface area. The full span, underslung, slotted ailerons used on some of the Junkers designs, and on the Fieseler Storch were far more effective at providing good lateral control near stall, as well as acting as landing flaps, and consigned park bench ailerons to the dustbin of aeronautical history.