Propeller problems
This is a 1928 technical memorandum from the NASA Technical Reports Server, catalogued as Technical Memorandum No. 491, that covers propeller problems for aeronautical engineers and researchers. The single picture pairs a labelled diagram of a streamlined body with a propeller and motor against a flow-field sketch showing streamlines converging toward a propeller disc, a plain engineering view a designer could borrow for schematic or airflow graphics.
