ENGINEERING TEST OF OVERHEAD ATTACHMENT SYSTEM FOR RAPPELLING FROM UH-1B AND UH-1D HELICOPTERS.
Final rept. 5 Oct 66-11 Apr 67,
YUMA PROVING GROUND AZ
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The Engineering Test of the Overhead Attachment System for Rappelling from UH-1B and UH-1D helicopters was conducted by Yuma Proving Ground, Yuma, Arizona, 5 October 1966 to 11 April 1967. The purpose of the test was to determine the structural adequacy of the overhead attachment beam in its in-use configuration, to determine the safe maximum simultaneous troop and cargo lowerings for the device and to establish criteria for a safety release. The test item was attached to a static ground-based mock-up simulating the helicopter. Shock loads of magnitudes and characteristics exceeding those expected in normal use were applied to the attachment rings of the extended arms. Deflections and stresses were measured. Dummies were lowered from the test item installed in a hovering UH-1D helicopter to gain in-use safety release criteria. The test item will safely support a maximum of two soldiers and equipment rappelling simultaneously from each end of the beam, or a maximum of one 500-pound external cargo package from each end simultaneously. Meticulous care is necessary in laying out and drilling the mounting holes in the beam. Criteria for a safety release were obtained during the hovering tests. No deficiencies or shortcomings were encountered in the installation or use of the test item. Internal cargo package size and weight will be limited to 14 inches in height and 300 pounds in weight.