Wind-Tunnel Tests on Airfoil Boundary Layer Control Using a Backward-Opening Slot
This NACA aeronautical technical report from 1932, issued by the NASA Technical Reports Server collection, presents wind-tunnel results for a wing with a backward-opening slot used to control boundary layer flow, written for aircraft engineers and researchers. Its charts plot lift increase against angle of attack and slot position, and a photograph shows a wing section with the slot cut into its upper surface. A designer could take from them the clean line-graph style of engineering plots and the simple cutaway view of a slotted airfoil as models for technical diagrams.
