A Flight Investigation of the Distribution of Ice-inhibiting Fluids on a Propeller Blade
This is a 1939 NACA Technical Note, issued by the National Advisory Committee for Aeronautics, reporting a flight test of how de-icing fluid spreads along aircraft propeller blades. The pictures are plain black-and-white photographs and line drawings of the propeller hub and fluid-distribution plumbing, with one page showing the XC-31 Army cargo airplane; a designer might draw on the clean technical diagram style and the precise labelling of parts.
