Frag Out! Magazine
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ric, appeared to be completely redundant. It involved taking pictures with five pairs of cameras and the di- mensions were analyzed later on. Unfortunately, as long as such a method could be used to measure the whole body, in the case of the head and the diversi- ty of its shapes, the method was too inaccurate. The second proposed approach was the Prince Charmin Method. 600 soldiers from Fort Devens were selected. After that, the computer selected 13 "Prince Charm- ings" who were to take part in further measurements at Natick Labs. At the laboratories, a pantograph was used to accurately measure heads of the soldiers. The subjects wore special caps that prevented their hair- cuts from interfering with the measurements. The pan- tograph collected information on X, Y, and Z coordi- nates for 400 points on the whole head. The obtained results were used to make wooden molds by using a numerical controlled milling machine (which was very modern at that time). It appeared, however, that indi- vidual variations in sizes of heads prevented the de- signers from determining several average sizes. A new method had to be developed. In the end, it was proposed that dimensions of head would be always measured in the same position by us- ing a special hemisphere with 27 probes – the axes of the probes were to intersect in one point. The subject's head was stabilized and the hemisphere was always lowered to the level designated by characteristic facial bones. In February 1973, Natick Labs constructed two devices called 3D Numerical Surface Descriptor, which were used to measure heads of 106 soldiers at Fort De- vens. The measurements were divided into 9 categories. After the analysis of the collected data and consideration of tolerances in the helmet molding process, it appeared that only 3 sizes would be required. Later, after comput- er-aided calculations, a sculptor made molds for 3 sizes by using the same devices that had been used for mea- surements, but with probes set to average dimensions. Thanks to that solution, the headform dimensions were obtained for sizes Small, Medium, and Large. It must be also highlighted that the data analysis also employed the initial database of dimensions of 6600 soldiers and 500 army aviators based on the anthropometric data from 1961 and 1966. The measurements taken with the use of a 3D hemisphere were used to adjust the 4 dimensions to the initial 9 categories. The report on results of works was presented in 1974. Back view of the retention strap. It was attached to the rear screw of the suspension with longer screw which came with strap. PASGT helmet prepared for parachute jumps with Desert 6-color Camouflage cover. Helmets in this configuration where used in First Gulf War in 1991. The "bunny ears" retention strap visible was provided to protect the jumpers nose against the hit of the helmet when the parachute was opening. equipment