Excursions of Head, Helmet and Helmet-Attached Reticle under +g Forces.
AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OHIO
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Open-loop centrifuge runs reaching 6gz were performed with 13 subjects wearing two different types of helmets the foam-padded standard HGU-2AP, and the Gentex 129-2 with adjustable web suspension. Rigidly attached to the helmet was a lightweight reticle with its crosshair about 1-12 inches in front to the left eye. Masses were attached at top and sides of the helmets. The total maximal load was limited to 40 ounces, and the largest lateral off-balance to 15 ounces. During the centrifuge runs, each subject attempted to maintain his gaze at a target directly in front of him. Hence, no voluntary motion of the head should have occurred. Position of head, helmet, and reticle were recorded photographically at each g-level. From the photographs, data on actual excursions of the head, helmet, and reticle were extracted and subjected to a computer-aided analysis. Involuntary angular head movements, as well as rotational displacements of the helmet on the head, are discussed in this paper in terms of pitch, roll and yaw. Also described are linear changes in the vertical height of the subjects eyes. Reticle displacements are discussed as they occurred in a frontal y-z plane. Author
- Human Factors Engineering and Man Machine Systems