Testing Nylon Rope Slings for Military Helicopters

Nylon rope slings for use with military helicopters, manufactured by Holloway Houston, are tested to meet Department of Defense (DoD) specifications. The rope slings are cycled at four cycles per second. The rope warms up and stretches as it is cycled, and as it stretches, more 'pull' is required to achieve the equivalent stretching force. The test that the DoD required was to apply tons of force to the sling, cycling the force between a maximum and minimum value, at a rate exceeding four times per second.