Detection of CH-53 swashplate bearing deformation - From a 3D dynamic model to diagnostics

The purpose of this paper is to present the research approach for the development of an algorithm for detection of a failure of the CH-53 swashplate bearing external spacer. The failure causes a lack of support of the swashplate bearing, thus creating a deformation of the outer ring. This study integrates the results of a new 3D dynamic model, developed for assessment of the defect pattern, and results from experiments. The research approach is planned in hierarchical phases. The experimental phases include a small scale specimen, full scale test rig, helicopter blades test facility and finally a CH-53 helicopter. The unique approach gradually simulates the real work environment of the swashplate bearing. The first two experimental phases and their results are presented. The first experimental phase is conducted on a small scale specimen and the second phase on a full scale test rig. Model results indicate that the lack of support has a defect pattern in both the radial and axial directions. These results are validated with the small scale specimen. In the future phases, the algorithm will be validated with data from the helicopter blades test facility and CH-53 helicopter.