ON AIRCRAFT ANALYSIS OF F-14 AIRCRAFT WING BEARINGS

Wing bearings on the Navy's F-14 aircraft are currently replaced at regularr intervals or upon detection of audible wing bearing noise. It is proposed to evaluate the feasibility of wing bearing condition assessment. This assessment plan includes test monitoring both strain gauge data from the structural members moving the wings and acceleration data from accelerometers temporarily mounted on the bearing casings for aircraft with good and worn wing bearings. Acceleration and strain data will be gathered for full, continuous sweep tests to monitor the steady state strain and acceleration conditions and determine a dynamic friction constant. Strain and acceleration data will also be gathered to monitor the force required to initiate movement (static friction force) from a variety of angles throughout the sweep regime. Additional processing will be applied to the data, including the fast fourier transform (FFT), calculation of the kurtosis (measure of impulsiveness), and calculation of jerk (derivative of acceleration) as quantitative measures of wing bearing wear. IMADS (Integrated Monitoring Analysis and Diagnostic System), developed by Technology Integration, will perform the data analysis, as well as determining peak strain and acceleration levels, root-mean-square (RMS) levels, bandpass filtering, and other statistical measurements.