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Aviation History
1942
1942 - 0574.PDF
23« FLIGHT MARCH 12TH, 1942 MAN VERSUS ALTITUDE simple phrase as "Air Ministry," or make simple calcula tions. The results of the writing tests are indeed very interest ing. In investigations conducted by the above-mentioned Institute about 40 per cent, of the tested men showed at about 20,000ft. "altitude" a temporary trembling and in voluntary movement of hands (v. Tavel). In some cases these disturbances were so intense that they incapacitated the tested man from further writing. It was also found that there is a distinct tendency for involuntary repetition, particularly striking in hand-writing tests of educated and normally intelligent men subjected to conditions of 20,000ft. altitude. In judging the results of the tests, allowance has to be made for the absence of the "responsibility factor," the lack of the danger element, and the fact that the tested man is aware of being on the ground and not in control of an aircraft. Test Reactions The reactions to these tests naturally differ from one individual to another. Only by a very careful co-ordina tion of psychological and physiological test results can a comprehensive picture be obtained of the possible behaviour of the pilot under real high-altitude conditions. It is of interest to note that the examined is in most cases com pletely unaware of the loss or diminution of his mental capacity and control, and usually views with surprise his twisted handwriting. It is, of course, impossible to state definitely the fitness for high-altitude flying from one test. The background, character, past habits of life must be studied, and the test repeated to obtain correct results. But experience has shown that there are certain symptoms frequent with most " unfit " cases: temporary disturbance of sight and speech, hallucinations and apathy. Physically trained men, and those accustomed to mountaineering, as well as matured men with considerable flying experience, have shown better high-altitude adaptability than young and perhaps keen capable pilots. It has also been found that a correct diet and sound digestion improve altitude adaptability—a fact still very much under-estimated in aviation circles. Importance of Diet While no diet can compensate for the oxygen deficiency, the meal which the crew partakes before flight can increase or decrease their "ceiling." Beans, peas, etc., and other gas-forming foodstuffs should be avoided. Furthermore, some food substances, such as fats, require more oxygen to oxidise them to carbon dioxide and water than others. If, therefore, a pilot's diet, and in particular the meal before his flight, is composed mainly of fats, his body burning more fat will be more susceptible to the strain of oxygen deficiency. On the other hand, carbohydrates, since they require less oxygen for their combustion, cause less strain on the body combustion process. It may, therefore, be suggested that a diet rich in carbohydrates (sugars) may to some extent improve the " ceiling " of the high altitude of the crew. To create a further source of quickly available energy- it is suggested that both before and during the flight the crew shbuld be given some quantity of glucose. The sugar which supplies the body with energy is glucose. In normal diet it is taken in complex substances, such as starch, etc., and has to be broken down to glucose, which is then burned by the body. If glucose itself is taken, in ready-made form, it can be assimilated directly into the blood, perhaps within half an hour, and consequently quickly sustain the body with new energy. It may well be that the idea of "direct fuel injection," which is making such headway in the improvement of energy output of engines, can be usefully applied to the human mechanism destined for high-altitude flying. Broadly speaking, there are, from the point of view of human resistance, three regions of altitude; the first up to some 9,000ft., where no special help is required ; the second from that height to approximately 18,000ft., where oxygen (whether with or without carbon dioxide—CO2—is still not unanimously agreed) must be supplied. Finally, the third zone, about 30,000ft., where a pressure cabin is necessary. For above this altitude an oxygen mask may supply enough oxygen, but the rarified atmosphere does not exert suffi cient pressure to force the oxygen into the blood-stream. Oxygen Equipment Information published by Boothby, Lovelace and Benson on investigations conducted in the American Mayo Labora tory of Aviation Medicine reveals further that,while oxygen is frequently efficiently used as low as 12,000ft. to coyn^r- act fatigue, if it is cut off at 25,000ft. unconsciousness sets in in three minutes, and above 29,000ft. in one minute, with a complete coma soon after. There is, therefore, no doubt that with modern fast-climbing aircraft the oxygen mask becomes a most necessary part of equipment, not only for specific altitude performance but for those eventualities in which the pilot may have to seek higher altitudes. The constant improvements in the design of the oxygen mask will make its use less cumbersome, and give more comfort and freedom of movement. An example of an improved type is shown on p. 195. This is an Italian ver sion specially designed for extra comfort in wear. This nose mask does not obstruct the mouth, and makes talk ing, yawning and eating quite easy. In the case of nausea —it is said—there is also no danger of soiling the mask. The flying personnel is rightly given more and more utility equipment which provides for their protection and comfort. The mobile oxygen units allow the crew to move about freely ; the automatic oxygen flo* regulator increases or reduces the oxygen supply according to the prevailing atmospheric conditions without being watched and operated by the crew. For flights of long duration at high altitude the pressure cabin provides for the protection of human life. Scientific opinion may yet be in disagreement as to the advantages or drawbacks of various types of equipment. ' While many problems have been solved, others remain to be tackled. The additional weight of the pressure cabin and the resulting detraction from the performance of the machine, the vulnerability of such a cabin to gun-fire, the heat compensation—these are but a few of-the problems which are involved in the technical research of high-alti tude flying. Yet research study, experience, and the practical appli cation of accumulated knowledge of the human aspect of the problem, have made possible the steady advance of human flight into altitudes which only/a short period ago were considered the domain of record-breaking adventure. ; —f- * US. May Join Training Plan COME new measure of co-operafionfin air training between ^ the British Empire and the U*ited States is regarded in Canada as a possibility now tjfat the United ^^fl faced with the problem of expanding itjtair arr Negotiations between the four £mp« courftil pating hvthe British CommonwcaltJtfAl&fEjjiiJygg Plan for an extension of the agreement o| vhiciT theplan operates are understood to be in akeyflnc^ar-tne moment. If co-operation withititps \np^cf States is decided on, it is likely representative**0^ ttaflboufitry will attend the nego- ftidns when ta^Tare started again, apedrding to informa tion f rom |DI|sypal Prelimiiarydiscossions concerning extensicurof the atn •' Ipnent were^fejferted in London some time^Sgo, according* statement'by Hon. C. G. Pow-a,-Canadian Air Minister, fsent position is undejwWSod to be that the Canadian Government had proposed a conference of representatives of the four^WnTrSefconcerned, Canada, the United Kingdomi Australia and New Zealand, to pursue the negotiations. It is expected that the conference will be held in Ottawa.
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