Langley Memoir on Mechanical Flight, Parts I and II / Smithsonian Contributions to Knowledge, Volume 27 Number 3, Publication 1948, 1911

The memoir chronicles systematic experimental work toward powered, heavier-than-air flight, presenting a chronological account of small flying models, aerodynamic tests with a whirling table, development of lightweight steam engines and launch apparatus. It explains why laboratory measurements differ from free-flight conditions, analyzes equilibrium and center-of-pressure issues, and records iterative trial-and-error design of wings, propellers, and supporting structures. Part of the text compiles detailed test data, field trial reports, and engineering challenges encountered during attempts to achieve sustained, controllable mechanical flight, with editorial additions completing later sections of the experimental record.