AAF agencies conducting similar research, which included "streamlining" cockpits to reduce crash injuries; design of seat for comfort, efficiency, and safety; and arrangement of windshields and gun-sights based on the pilot's eye position. Proposed "safety engineering" studies included the establishment of minimum dimensions for escape hatches, based on measurements of large flyers in full gear, and a general project to determine location and dimensions of escape hatches, passageways and installations to protect personnel during crash landing and "ditching" (forced landing on water). As might be expected from the nature of wartime research in military anthropology-a series of immediate, urgent requirements-personal equipment received more attention than any of the other major applications of AAF anthropology. In personal equipment the relation of man to material was immediate and obvious. The projects already described-selection of personnel, construction of full-scale models, gun-turret and airplane design-were relatively longterm undertakings, involving the indoctrination of military aviators and engineers in a point of view. Such studies could hardly be carried on when, for example, sudden tactical developments led to an urgent request from a combat theater for a larger number of oxygen masks or garments that were still experimental, and the number of sizes, dimensions of each size and proportions of each size in the total were required to be "immediately" worked out; or when manufacturers were continually submitting pre-production samples of garments which required testing for size before production might begin; or when past deficiencies had to be remedied or new ideas incorporated as soon as possible in the full course of production, where every day meant thousands of items. Quite properly, most of the time and volume of work of the AAF anthropological program was devoted to personal equipment.12 The following brief account of the oxygen mask study can only indicate some highlights of this intriguing problem. Since the first attempt to apply anthropometry to aviation medicine, its emphasis had long since shifted from analysis and evaluation to original design. Even before the head models were constructed, all available masks, allied and enemy, were thoroughly tested for fit on sizeable series of individuals measured according to the Facial Survey Blank. Successes and failures of each size of each mask were related to facial dimensions, and proportions of AAF flyers fitted could thus be estimated. Recommendations were made for redesigning and resizing, and specific data supplied, with the result that subsequent masks had a much greater percentage of fits. It was determined that three sizes were necessary for AAF masks, and the percentages of these sizes were established for general production and for issue to specific groups of flyers. It was found, for example, that fighter pilots. and especially photographic reconnaissance pilots required a larger proportion of small and medium sizes than did bombardment crews. Based on anthropometric data and on consideration of the goggles and helmets with which masks must be integrated, a new mask was designed and developed. This was finally standardized as the A-13, described under the section on oxygen equipment. It proved to fit virtually all AAF flyers, including women, and to be suitable for a number of purposes, including resuscitation of unconscious flyers. Other types of masks, such as a full-face mask incorporating goggles for waist gunners, and combinations of plastic and rubber materials were experimentally designed. Anthropometric data were translated into tailors' measurements in Tables of Sizes and Percentages, as noted, and were supplied to the organizations developing and engineering the production and procurement of AAF flying clothing. Jackets, trousers, helmets, and gloves were thus sized, and a table for shoes planned. These tables were routinely utilized in the design, sizing, procurement and issue of flying and other clothing for AAF flyers. Thus, the number of sizes required and the dimensions for each size were tentatively established for a proposed garment, based on knowledge of its function, design, material and associated clothing. A sample of each size was made and tested on subjects of known dimensions, and the size schedule modified as required; more or fewer sizes might be necessary, or different dimensions indicated. These dimensions were included in the specifications. Finally, the percentages of each size in the total production was determined. As for actual production garments, samples of flying helmets were routinely submitted for size tests before manufacturers were permitted to begin full production, and periodic samples of all garments were routinely inspected for conformity with the dimensions in the specifications. A study of glove sizing led to the construction of model hands and to the experimental design of gloves with curved fingers. A lighter touch was afforded by the determination of the required range of adjustment in suspenders to be worn with high-waisted and low-waisted trousers. A consideration frequently overlooked by airplane, turret and clothing designers was the bulk inherent in most flying clothing. It was found that even in electrically heated clothing, adequate insulation entailed bulk which, in the limited space available, could not be disregarded and might actually impede efficiency. Increments added by various standard outfits (shearling, electrically heated, and down-filled) to each dimension measured in the body-size survey were determined and compared. These figures indicated relative percentages of 262297-55- 18 the various outfits for the total clothing program, since the bulkiest could not be used in certain crew positions. They formed an indispensable supplement to body-size measurements used by airplane and armament engineers; they warned the clothing designers of the limitations imposed by aircraft, and they indicated regions of the garment where bulk might be reduced. The initial turret investigation led, as already noted, to work on steel helmets and on bulk in flying clothing; a third avenue was toward parachutes for turret wear. Limited space had made it virtually impossible for gunners to wear parachutes over adequate clothing in some aircrew stations which offered the best opportunities for emergency escape. Expressly designed parachutes were solicited, tested in turrets by selected subject wearing various clothing outfits, and the results used to make further recommendations to the designers. The required sizes and range of adjustment for parachute harnesses were studied; work was planned on the integration of the one-man life raft with the parachute harness, and on the design of the life raft itself. Anthropometric data were applied to a number of projects on which considerable work was done but which will merely be listed in order to keep the present discussion within reasonable bounds. These projects included (1) location of earphone sockets on helmets, (2) special combat devices for pursuit pilots, and (3) a project stemming from work on clothing and only remotely anthropological, involving the design and location on outer garments of a tab for attachment of a clip at the juncture of the flyer's oxygen equipment with that of the ship. The background, history and operation of physical anthropology in the AAF have been briefly summarized. Initiated as a consequence of pressing military problems involving human dimensions, the basic procedure was an anthropometric survey of Army Air Forces flyers, several thousands of whom were measured. These measurements were applied to the selection of personnel and to the design and sizing of military aircraft and associated equipment, including gun-turrets, oxygen masks, flying clothing, and parachutes, with the aim of increasing the comfort, efficiency, visibility, and safety of flying personnel. The AAF anthropological program served as a model in the organization of a similar project by the Armored Command, Army Ground Forces. Several trends characterized the AAF project: (1) There was a consistent transition from analysis and evaluation of existing items to original design of new equipment, exemplified in connection with cargo airplane seats, oxygen masks and clip tabs, and prone position harnesses. (2) The original problems extended into many fields related only through the human element. Turrets led to studies of clothing bulk, steel helmets, and parachutes; oxygen masks, to work on all head and facegear; clothing, to oxygen equipment; and size analyses of specific turrets, to safety engineering in general. This emphasized that the designer of equipment for human use should begin with man himself rather than relegate him to the subordinate position in which he is too often found. (3) As a consequence, the physical anthropologist could occupy a central position as human engineer, as exemplified by the numerous liaison functions he came to perform in the Army Air Forces. For example, parachutes and gun-turrets had been designed separately; so had goggles, oxygen masks and helmets; and so had flying clothing and oxygen equipment. Anthropologists initiated integration of all these sets of material. High Altitude Studies Physiological problems encountered at high altitudes had always received prominent attention in the Aero Medical Laboratory, and the elevated operating altitudes reached during World War II emphasized and accelerated work in this field. The Laboratory was fortunate in having a background of experience and facilities for investigations in this area, the need having been recognized quite early in its history, but it was not prepared to meet the many stringent requirements imposed by modern combat flying. In spite of this, difficulties were overcome, deficiencies remedied, equipment improved and operations made less hazardous. Contributions of the Aero Medical Laboratory in the field of high-altitude studies may be divided as follows: (1) development of oxygen equipment, (2) pressure breathing, (3) explosive decompression, and (4) thermal problems. (Although investigations of the effects of toxic gases and decompression sickness received attention from time to time, the contributions in these fields are not considered of sufficient importance to warrant a detailed discussion.) In the first of these major studies, the principles of respiratory physiology played a dominant role both in assisting in the design and evaluation of new types oxygen dispensing equipment and in establishing rules of conduct in their use at high altitudes. Likewise, in the fields of explosive decompression and thermal studies, basic physiological principles of circulation and respiration were heavily relied upon. 13 of Oxygen Equipment. At the beginning of World War II there were two general types of oxygen systems in combat aircraft. One was the low-pressure continuous flow system, which consisted principally of each oxygen cylinder being connected so that oxygen was supplied from a common filler valve and discharged into a common distribution line. The regulator in this system. |