The effect of multiple fixed slots and a trailing-edge flap on the lift and drag of a Clark Y airfoil
This is a 1933 NACA technical report by the National Advisory Committee for Aeronautics, written for aeronautical engineers and wind-tunnel researchers, on how multiple fixed slots and a trailing-edge flap change lift and drag on a Clark Y airfoil. The pictures are mostly lift-coefficient and drag plots against angle of attack, plus airfoil section drawings and slot-combination diagrams with dimensioned contours, showing how each slot arrangement shifts the curves. A designer might take from them the clean line-graph style of engineering data and the dense black-and-white profile drawings of wing sections.
