Principles and design of aëroplanes
A 1912 engineering manual by Herbert Chatley, published in New York by D. Van Nostrand for aircraft designers and students in the first decade of powered flight. Line diagrams label early airframes with force arrows, load equations and centre-of-gravity marks, plus perspective sketches of control linkages — a source of trussed girder lattices, annotated schematics and technical lettering.
