A Preliminary Investigation of a New Method for Testing Aerofoils in Free Flight
A 1922 report from the Aeronautical Research Committee, distributed through the NASA Technical Reports Server, documents a preliminary method for testing aerofoils in free flight, written for aeronautical engineers and researchers. The first picture is a photographed biplane with a trailing wing in flight beside a gauge assembly, and the second is a plain line graph with labelled curves of lift and drag against angle of attack, offering a designer clean reference for technical charts and diagrams.
