The BARBEY Report. An Investigation into Controllable Pitch Propeller Failures from the Standpoint of Full-Scale Underway Propeller Measurements.

摘要

This report reviews the previous experience with Controllable Pitch Propellers (CPP). Two ships of the FF-1052 class were fitted out with CPP's for test and evaluation. One of these ships, the USS BARBEY (FF-1088), experienced difficulties followed by catastrophic failure of the CPP mechanism after a relatively short period of operation. As part of an extensive investigation into the general CPP design philosophy with particular reference to the failures experienced on BARBEY, the David W. Taylor Naval Ship Research and Development Center (DTNSRDC) instrumented the CPP mechanism on BARBEY and conducted full-scale drydock, dockside, and underway tests. The results showed that the quantitative and qualitative assumptions made in the structural design and propeller blade loads (especially during maneuvers) were not compatible with reality. More explicitly, the propeller blade palm acts as a nonuniform, nonlinear loading mechanism on the blade bolts. It was found that this mechanism causes excessive loads which lead to fatigue damage in the bolts and crank disk. This was most likely the direct cause of the original bolt failures and, together with geometric design and metallurgical deficiencies, contributed significantly to the crank disk failures.