The mutual action of airplane body and power plant
This NASA technical report from 1932 is an aeronautical engineering study of how an airplane body and its power plant interact, written for engineers and aircraft designers. The pictures are plotted charts with curves on labelled axes, showing efficiency against a speed ratio and a family of fitted lines, with values such as lambda, eta and k_d marked along the scales; a designer might take from them the chart-reading conventions of mid-century engineering graphics, with stepped grid lines and small handwritten-style numeric labels.
