Skin Drag of High Speed Aircraft: The Laws for the Drag of Smooth and Rough Flat Surfaces Applied to Aircraft

AS aircraft become aerodynamically cleaner, an ever‐increasing proportion of the drag becomes pure skin drag. The known laws of the drag of flat plates enable the friction drags which occur at the Reynold's Numbers met in high‐speed flight to be approximately calculated. In addition, the very important effects of surface roughness which occur at high speeds may be assessed in a practical manner for aircraft from the known data on flat plates.