NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS LANGLEY FIELD VA LANGLEY AERONAUTICAL LABORATORY
A large number of data covering the wing stressing of six different civil aircraft ranging in weight from 2000 to 6000 kg are subjected to statistical analysis. Results from stress measurements in flight operation afford data for analyzing the frequency of appearance of certain parts of the static breaking strength during a specified number of operating hours. Appropriate frequency evaluations furnish data for the prediction of the required strength under repeated stress in the wing structures of aircraft of the different stress categories for the specified number of operating hours demanded during the life of a component. The measures adopted will depend on the magnitude and frequency of the loads during the life of the aircraft and will vary with the type of aircraft, purpose of use, and atmospheric conditions.
Translated from Die erforderliche Zeit- und Dauerfestigkeit von Flugzeugtragwerken (Germany East and West), 1938. Translated by J. Vanier. Text in English.