Air Propellers in Yaw
A 1937 NASA technical report, Air Propellers in Yaw, issued for engineers and aeronautical researchers studying how propellers behave when the aircraft yaws. Its one picture is a photograph of a laboratory setup labelled as the electrical balancing units, showing propeller-like rigs mounted on a bench. For designers, it offers a plain, instrument-driven view of mechanical test equipment with dense cables, weights and metal fixtures under overhead light.
