40 although there is minimal curve on the suction side surface 58 in the last third of the length of the flap 34 the leading edge 52 of the flap 34 is designed such that it remains masked behind the profile of the strut 32 fig4 throughout its incidence range this minimizes the pressure differential between the accelerated flow on the pressure side of the gap 59 fig2 3 and the lower speed flow on the suction side of the gap 59 in operation referring to fig2 the continuous curvature of the side surfaces 46 48 of the strut 32 and the controlled deceleration of the flow at the tapered rearward portion provide a controlled velocity distribution of the flow to the leading edge 52 of the flap 34 in the zero deflection position shown in fig2 the airflow flows from the trailing edge 44 of the strut 32 to the leading edge 52 of the flap 34 and along the side surfaces 56 58 of the flap 34 in the fully deflected position shown in fig3 the peak thickness 68 of the pressure side surface 56 of the flap 34 is near the trailing edge 44 of the strut 32 however the.