The elimination of dead center in the controls of airplanes with thick sections
A 1922 NASA technical report on aircraft control design, aimed at engineers and aeronautical researchers, that treats how rudder and fin shape affect airflow. Its pictures are line diagrams of a plan-form change to a rudder, with dimensioned top views and flow sketches showing airflow about old and new rudder shapes. A designer might take from them the clean technical diagram style, with dimension lines, labels and streamlined hatched profiles.
