"Schneebeli" and "Birger" silencers
This is a NASA technical report from 1923 on aircraft engine silencers, the Schneebeli and Birger designs, catalogued by the NASA Technical Reports Server and drawn as engineering line diagrams for engineers. The first picture shows a manifold of curved exhaust pipes feeding a single collector and a flared outlet, while the second gives orthographic views of a bulbous Birger silencer with dimensions marked in millimetres, useful to a designer for clean technical line drawing and dimensioned plan-and-elevation layouts.
