R. N. DuBois
naca-tn-210
Dec 1924
The desirability of a test to determine the performance of aviation engines at altitudes was early recognized. With information obtained from such a test, the performance in flight could be predicted, possible engine failures at high altitudes foreseen, and the danger to pilots therefrom greatly minimized.
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http://naca.central.cranfield.ac.uk/reports/1924/naca-tn-210.pdf