STRENGTH LOSSES IN NYLON PARACHUTE MATERIALS WITH TIME, EXPOSURE AND USE
ARMY NATICK LABS MA CLOTHING AND ORGANIC MATERIALS LAB
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The findings of recent tests on aged and used nylon parachutes are reviewed with respect to service life limits and to implications as to the technical nature of the degradation problem. The data tend to confirm that the current 10 year or 100 jump limits and related repair cost limit schedules do not present a hazard. However, the scatter and contrasts of results make questionable the validity of small samplings and extended predictions. No consistent and pervasive trends were found to be directly related to time in storage or service, or to jump history except for initial mechanical effects on suspension lines. The results evidenced marked differences in the specific susceptibilities of various materials, and a number of degrading influences and types of effects on physical properties. It is concluded that a wide distribution of strength levels is to be expected in older parachute populations, and that the risk problem is with the exceptional cases rather than with the average condition. A number of possible chemical and structural change mechanisms are discussed.
- Gliders and Parachutes