Abacus giving the variation of the mean pressure of an aviation engine as a function of its speed of rotation

Margoulis, W
naca-tm-12
March 1921


Comparing the results of the calculations for computing the mean pressure of an aviation engine for any number of revolutions, with those of experiment, the writer, by numerous examples, shows the perfect agreement between them. This report will show that, by means of a special abacus, an engineer can instantly plot the characteristics of an engine.

An Adobe Acrobat (PDF) file of the entire report:
http://naca.central.cranfield.ac.uk/reports/1921/naca-tm-12.pdf