Investigation of Factors Influencing Propeller Blade Failures.

A flight and ground test program was conducted to examine vibratory and steady propeller blade operating stresses occurring in normal and transient abnormal operation of several types of reciprocating engine powered general aviation aircraft. The objectives of the tests were to evaluate such stresses as a possible cause of early propeller blade fatigue failure and to determine whether they were inherent in the characteristics of the engine-propeller combinations, or attributable to such factors as tolerance spread between identical models or accumulated time in service. The results also were considered in respect to current design and certification standards.