Field Evaluation of the Shock Pulse Technique to UH-1H Series Helicopters.
Abstract
Shock Pulse readings were taken on four (4) models of the UH-1, (Models: C, M, D and H) using an off-the-shelf SKF, MEPA-10A. Readings were collected on the tailrotor driveshaft hanger bearings and the forty two degree tailrotor gearbox. The shock pulse technique works on the principle that a discrete fault, such as a pit or a spall, will cause repetitive impacts of short duration. These impacts will cuase shock waves to propagate through the bearing structure causing a pulse displacement input to an accelerometer, suitably, attached to the bearing structure. The output of the accelerometer passes through a high gain amplifier tuned at the resonant frequency of the accelerometer (this amplifier then acts as a sharp band-pass filter). After the signal is processed the output is displayed on a counter which provides the frequency of peaks above any desired peak amplitudes. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 05, 1974
- Accession Number
- ADA054906
Entities
People
- Edward F. Covill
- J. Thomas Harrington
- John A. George
- Timothy C. Mayer