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Aviation History
1919
1919 - 0026.PDF
mm Statistical information would be useful for such purposes as choosing routes and the sites for aerodromes and buildings. The statistical informa- tion at present obtainable differentiates between areas of 50 or 100 miles square ; for instance, between the meteorological conditions which are met with on opposite sides of a mountain chain. But there is as yet little infor mation relating to the local variations in meteorological conditions. Statistics already collected are available for determining such questions as whether it is better to leave Switzerland on the port or starboard hand in flying to Italy, or whether it would pay to go round southwards by the Azores in flying to America. On the other hand, the statistical information at present available is not capable of discriminating between the average meteorological conditions of two alternative sites for aerodromes situated within a few miles, or even 20 or 30 miles, of one another, except in so far as it shows which of the meteorological conditions are likely to be the same in two neighbouring sites. Statistics show, for instance, that the cloudiness and rainfall in two neighbouring sites may be the same unless special circum stances interfere. On the other hand, fogginess and windiness depend almost exclusively on such local conditions that the present statistics are of little use except for the actual station at which observations were made. Perhaps, later, aerodromes will accumulate their own data. A small staff at the Meteorological Office would collect the available useful information, tut such a staff would have to be directed by someone in touch with aeronautics, in order that the information might be collected and tabulated in the form most useful for flying. He would have to decide such questions as whether frequencies or mean values should be dealt with. In dealing with wind statistics, for instance, it is more useful to know the number of hours during which certain winds blow with certain strengths, and from the various directions, than it is to know the mean wind velocity or direction. If weather stations are going to be established at terminal and intermediate aerodromes in connection with civil aerial transport, it will be necessary to overhaul thoroughly the character of observations taken, in order that special attention may be paid to the data which are most important. It is advisable that a system should be organised by which observations are taken and recorded regularly by aeroplanes travelling on defined routes. The work of collecting and comparing these statistics, and the superintend ence of instruments might be undertaken by the Meteorological Office. It has been pointed out by various members of the Committee that civil aerial transport will inevitably have to be worked on international lines. It is impossible to forecast what measure of international co-operation will be possible after the war, but it may be pointed out that for many years previous to the war the International Meteorological Committee has done successful work in organising international exchange of meteorological infor mation and international co-operation in meteorological research. It seems certain that it would be advisable to consult with the aerial transport autho rities in the allied countries before deciding on any definite plans for a weather service for aerial transport. (2) Forecasting. An extension of the present system in operation at the Meteorological Office should provide everything that can be expected in the present state of our meteorological knowledge. The high average correctness of weather forecasts will doubtless be improved. I* Present system.— The present system involves taking observations at certain places two or three times a day, and communicating by telegraph with a Central Office, where the weather maps are made and the forecasts issued. Forecasts for 12 or 24 hours ahead at two or three fixed hours should be telegraphed from the Central Office to the termini and intermediate aerodromes. Directions in which present system could be extended. 1. Extension of range covered.—Weather telegrams are already obtained from a few distant places, as Iceland, Cairo and the Azores, and from ships by wireless. The number of distant stations could be increased and the range extended so as to include Russia, the Ralkans, North Africa and America. Before the war the observations sent by wireless from ships usually arrived too late to be used in the forecasts, but the growing import ance of messages from the Atlantic in connection with aerial transport will make it worth while to organise these reports in such a way that the messages arrive in time. For this purpose fuller co-operation with the Royal Navy and the Mercantile Marine should be sought. By increasing in this way the numbei of data on which forecasts are based, it will be possible to increase the size of the region for which the forecast is issued and to make it more accurate in all ways. 2. Extension in the number of weather conditions predicted.—At present the forecasts are adapted to the needs of people on the ground or the sea—sailors, farmers, travellers, &c. They might be much more useful to flying men if they were made to include the heights at which clouds are to be expected, and the velocity and direction of the upper winds. The first of these has not yet been attempted, but as the data furnished by aeroplanes become more numerous such forecasts may become accurate and useful. The second, the forecasting of wind at various heights, has already been practised success fully in France by the Meteorological Section there, and there is no reason why it should not be carried out even more successfully over a wider range by the Meteorological Office. Such forecasts would be facilitated by increasing the number of upper air observations and of those on mountains. 3. Knowledge of the momentary weather.—For this purpose the present system is quite inadequate. A continuous weather service would be necessary. All landing grounds would evidently be suitable weather observation stations, and continuous readings and reports could be arranged for, if necessary. In distributing information two systems could be used. Either the obser vations could be communicated at frequent intervals, say, every hour, to a Central Office, and could then be telegraphed or telephoned when required to aerodromes, or the observations could be taken only when required and tele phoned direct to the termini. The advantage of the Central Office is that it would have a more com prehensive view of the weather conditions over the whole of Europe, and, moreover, an expert could be kept at the Central Office who would have the present conditions at his fingers' ends, and would know which were liable to a sudden change. The chief difficulty which is likely to be experienced in this branch of the weather service is that of communicating the observations sufficiently quickly to the termini. It seems probable that the direct method would be quicker than the Central Office method. Another point in favour of direct com munication is that the observations taken at an intermediate landing ground are only immediately interesting to the termini of the route on which it lies. These two points appear to us to outweigh the advantages of the Central Office method. If there is a direct telephone wire along the route or constant wireless com munication, the whole problem is greatly simplified. On the other hand, if the ordinary telephone lines have to be used, some sort of priority for weather messages will have to be arranged if they are to be of any real use. The type of observations which could usefully be taken at the intermediate landing ground needs some consideration. The height of the clouds is one of the most important things for a pilot to know. It would not be difficult to fit a range-fiader which would give the height of the clouds at * glance. JANUARY 2, 1919 The veolcity and direction of the wiud at various heights is also important but it needs a skilled observer to make a pilot-balloon ascent, and even then the information is not available for about three-quarters of an hour after the balloon is sent off. It seems hardly possible to use pilot-balloons in connec tion with this branch of the weather service, unless balloons are sent up at regular intervals of two or three hours, and the last result is communicated in response to any enquiry from a terminus. On the other hand, on a clear day the upper wind at any particular height would be found in a few seconds by means of a smoke-shell fired verticallv and timed so as to explode at the right height. One of the chief functions of the observer at the landing-grounds would be to report the appearance and disappearance of fog on their own aerodrome. This needs no very special training, but trained and experienced observers will be needed at every important aerodrome where upper-air work is carried out, and also at places from which local or general forecasts are issued. A corps of such observers should form an integral part of the military or civil air services, as, in fact, they already form a part of the Royal Naval Air Service. MONTAGU. August 21st, 1917. G. I. TAYLOR (Major). APPENDIX H. Preliminary Memorandum on Inter-communication between Aircraft and the Ground, and also Inter-communication between Aircraft and Aircraft. [This is not printed.1 APPENDIX I. Safety Appliances for Commercial Aircraft. r. The risk of forced landing of aeroplanes is the first of all risks run, and for this two remedial possibilities exist. The most important expenditure on safety and on the general economy of aerial transport is the provision of alighting grounds along the flying routes, and no suggestion herein is put forward in substitution for, or in diminution of, the importance of these route- alighting grounds ; the second is the extension of the use of multi-engined aeroplanes. Airships would usually be provided with more than one engine in any case. 2. In considering the detail of appliances to be used in connection with safety on aircraft, regard must be had both to the prevention of accidents and the best method of dealing with the dangers arising after accidents have occurred, whether on the ground before commencing a flight, in the air, or on landing. It must be realised that experience shows that an accident to the machine by no means involves, in the majority of cases, an accident to the flyer and passenger. It is probably that the civil use of aircraft will conduce to much greater safety than the useful standard already reached, quite apart from any appliances—especially since extreme war performance and manoeuvring are not called for. 3. Fire.—The direction in which study is advisable in all types of aircraft is to try to arrange for the main petrol supply to be situated clear of the hot parts of the engine and away from the magneto, and to see that the exhaust pipes are kept clear of the petrol pipes, and the exhaust discharge is in such a position that a spark cannot ignite any surplus petrol flowing away in the case of over-filling of tanks, or any vapour from exits or leak ages. In some engines gauze boxes can be fitted to induction pipes, and the inlet ducts to carburettors arranged to draw the air from outside the structure. 4. Experiments have been made on magnetos by making small alterations to enable them to be immersed in an inflammable vapour, and it has been found that after lowering and raising the pressure on such vapour it did not fire the mixture even when overflow sparks occurred at the safety gap. ThU preliminary study should be prosecuted, and could probably result in the general introduction of such magnetos. Meanwhile the whole petrol system is kept clear of electrical devices, such as magnetos and wireless, in case leakages of petrol should give rise to vapour in their vicinity. A desirable feature which has been suggested as useful is an arrangement for shutting oft the petrol from the jet instantly. This might take the form of a spring - controlled mechanism acting on a needle fitted with a quick thread, which, through the action of a spring, could be made to stop up the jet orifice. The object, which is to ensure the engine stopping quickly when desired, could be effected in various ways, and here also is a field for experimental development. Incidentally this might avoid the danger of an engine running backwards if overheated. 5. All overflow pipes and pipes between the carburettor and the atmo sphere are led well outboard, and care is taken in the making of exhaust manifold joints to avoid the danger of their blowing out. In the case of rotarv engines, which usually have no exhaust pipes, it is usual to cowl them completely with metal cowls and to keep those supporting members which may come near the exhaust free from exposed inflammable material. Any fuel or oil that may be thrown out from the engine is kept within the cowl, and if it should catch fire no damage results. Nevertheless such cowls should be drained. The aircraft of to-day have, except in the case of airships only, small margin of useful load, and their utility is jeopardised by compulsory carrying of additional weights. Hence fire extinguishers do not form an obligatory equipment until the aeroplane attains considerable dimensions, but it is eminently desirable that they should be carried if possible. Small extinguishers should be available at all aerodromes, but they must not contain ingredients likely to harm fabric or wood work. 6. Parachutes.—In airships, kite balloons, and balloons, the use of these, though requiring decision and courage on the part of the user, does not offer the same difficulties as in the case of aeroplanes. It is, however, in the present stage of development inadvisable to jump in a parachute under a height of about 500 ft. As regards aeroplanes, opinion is divided as to the advisa bility of employing parachutes, both for the above reasons and because there is difficulty in fixing the parachute in such a position that no part of the aeroplane will be fouled when the jump is taken. Moreover, a substantial proportion of the accidents which occur only become accidents after the ground has been reached, or too nearly approached for the parachute to be useful. The best position for a parachute would seem to be either on the underside or on the side of the body, and a comparatively flat and compact parachute case has already been designed for this, and has been successfully employed in experimental flights with airships. It may be said that parachutes would only be employed in the case of a serious outbreak of fire, or the breakage of some vital part of the machine. In the latter case it would generally be problematical whether the parachute could be got free—in the former, the problem of fire is best dealt with by preventive measures. Meanwhile the carrying out of experiments is to be encouraged. 7. Air or Land Brakes.—These have a distinct promise of utility for land ing in restricted areas. Several forms of air brake have already been tried with more or less success. As soon as engines have reached a high standard of reliableness a promising form of air brake is the variable pitch and rever sible air-screw. Land brakes might take the form of a plough either operated by hand or automatically making contact with the ground. A similar purpose would be served by wings of variable surface or with the camber and angle of incidence capable of being altered. This latter development might come with the further increase of flying speeds which is often foreshadowed. 8. Instrument for Ascertaining the Attitude of an Aeroplane in a Cloud.— It is understood that considerable importance is attached to this by pilots, 26
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