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Aviation History
1922
1922 - 0122.PDF
difficulty in making sound castings of known lighter alloys. The need for research seems to be obvious, but it must be a sort of research that will help to produce the castings required, and not merely to make sample test pieces of some particular material. Some^of these aluminium alloys are required to maintain their strength when hot, and consequently their behaviour at temperatures above the normal must be investigated. The amount of power that a petrol engine can give is frequently limited by the speed at which it can run. This in turn is sometimes limited by the risk of failure of the bearings. Very little indeed is known of the properties of plain bearings under the condition in which they have to work in an aero plane motor. It is generally considered that the criterion of safety of a bearing is obtained by multiplying the average pressure by the rubbing speed, and if the result obtained is lower than a certain figure the bearing will be satisfactory. On the other hand, the designers of the Michell bearing assure us that the higher the rubbing speed the higher can be the load per square inch. Here we have two opinions which are diametrically opposed, and it certainly needs research in this direction to enable designers to fix their bearing surface with some degree of certainty. The properties of ball and roller bearings also need investigation, as there is much uncertainty amongst designers as to their most suitable form and the loads that can be carried. Fuels.—The type of fuel that is used in a petrol motor has a considerable effect upon the working of the motor. We know that the addition of benzole to petrol enables us to increase the compression of the engine without fear of detona tion, and that other materials can be added to give similar results. Research is needed to determine the most suitable fuel that can be obtained at a commercial price and in commercial quantities. Research for Constructors Aeroplanes.—One of the most important processes with which the constructor is concerned is the joining of materials together, particularly the gluing of wood and the soldering, brazing and welding of metals. There is still no waterproof glue that is altogether satisfactory, and although much work has been done on the subject there is room for further re search. The methods of soldering, brazing and welding have always been largely shop processes. There is little information to be had on the subject, and as these three methods are constantly used by all aeroplane constructors, further knowledge would be of advantage. Fluxes in particular call for attention, especially to determine which are easily useable and do not set up corrosion. There is another peculiar problem which constantly presents itself to jthe aeroplane maker. It is to make stiff light forms of various shapes suitable for fairing which are weatherproof and, if possible, fireproof. In the general way the strength of these parts is unimportant; the chief requirement is that they shall keep their shape. Engines.—The making of aeroplane engines presents a variety of problems in the shops. In the general way it is much easier to machine parts to the required degree of accuracy than to be certain that the material of which they are con structed is of the required strength and free from faults. The need for steels of uniform quality and of higher tensile strength has already been mentioned. The constructor is particularly concerned with the correct heat treatment of the material that he receives. Included in the heat treatment of metals must be case hardening, particularly of intricate parts. The life of most aero engines could be improved con siderably if certain parts were specially hardened. This is not done on account of the difficulty of knowing that the hardening will be carried out in a manner which will not injure the rest of the part. Here I think is a large field for investiga tion, but it is of a practical rather than a theoretical nature. Research for the User The requirements of the user in the matter of research naturally apply to the actual operation of aeroplanes. Many of his problems would be removed or at least made easier by the researches already indicated, but certain of them are apt to be ignored both by the designer and the constructor. One of the most important of these is safety from fire both in flight and in case of accident. Safe landing in small aerodromes is likely always to be of interest to the user, who very naturally objects to paying THE PROGRESS By Brig.-Genl. R. K. BAGNALL-WILD, CM ALTHOUGH extremely interesting, the restrictions of space prevent publication in full of the paper read before the Air Conference by the Director of Research. It is hoped, FEBRUARY 23, 1922 more rent for his ground than is necessary for safety. The research already suggested in connection with control at low speeds is possibly the most important factor of landing in small aerodromes, and probably more advantage will be gained by a knowledge of this subject than by the use of wings of an abnormally high lift coefficient. Landing gears in the general way offer possibilities of improvement, but this is rather a matter of Individual design than i of any particular research. Alighting on Water.—There are many countries in which it is difficult, if not impossible, to find ground suitable for aerodromes, but where there is plenty of water which can be used for the purpose. In some cases it is convenient to have aeroplanes which can make use either of land or water for alighting or getting off. We have a fair knowledge of properties of floats and hydroplane boats. There is no doubt that this knowledge might be extended by further research. In the construction of boats and floats we still have a lot to learn, but this will probably have to be a matter of direct experiment. The user is much interested in the comfort of his passengers, and in this matter the silencing of the engine and of the air screw is of importance. The silencing of engines is fairly well understood, but involves in general a rather heavy expenditure of weight. The silencing of airscrews is more difficult, and perhaps the problem could better be solved by placing the passengers in cabins which are more or less soundproof. The subject is one on which little is known, and research might indicate methods of improvement. Meteorology.—The user is interested in weather prediction, more especially in anything that will affect visibility, such as fog and snow. He also wishes to have reasonable warning of dangerous extremes of weather, particularly in countries which are liable to violent storms. He is also interested in knowing the direction and strength of the wind at various heights, so that he may economise time and money by taking advantage of favouring air currents and in avoiding those which are unfavourable. Navigation.—The question of navigation presents no difficulties so long as the visibility is good. There are many reasons why it is not convenient to fly always in sight of the ground. When the wind is favourable it will generally pay to fly high, and it is certainly more pleasant to be in the sunshine above the clouds where the air is almost always steady, than to be tossing about just beneath them. There are many ways in which wireless telegraphy and telephony can help, but it is essential that the gear carried on the aeroplane shall be as light and as simple to use as possible. Wireless control of the aeroplane itself, from the ground, is certainly a possibility of the future, and it may be that the pilot of an air liner will give up the control of the aeroplane when within certain distance of his landing place to a ground pilot, who will bring the aeroplane into port. Multi-Motor Aeroplanes.—In running an air service it is essential that forced landings of any sort shall be as infrequent as possible. If we could absolutely cut out the chance of motor failure we should practically achieve this end. Aero planes have been made in which the power unit has been divided up into any number of motors up to six, but for many reasons the single motor aeroplane is still, in practice, as reliable as the multi-engine machine. There is certainly room for research in this direction, and it will probably need close co-operation between the engine designer and the aeroplane designer if a solution is to be found. Conclusion.—The high position that this country holds in the development of flying is, I think, due almost entirely to the wisdom of the Government that set up an Advisory Committee and instituted research work at the very beginning of flying. The work carried out at the National Physical Laboratory, the Royal Aircraft Establishment and the Testing Stations of the Royal Air Force, could not possibly be done by private enterprise, and it is by the information gained and the standard set by this work that the industry is enabled to produce aeroplanes which cannot be rivalled in any other country. It is the opinion of the writer that help of this kind is of greater value than direct subsidy, and he earnestly hopes that even the pressing need for economy will not prevent research being carried out in the future in the same spirit as it has been carried out in the past. OF RESEARCH .G., C.B.E., F.R.Ae.S., Director of Research however, that in the following risumi no points of primary importance have been omitted. The Director of Research prefaced his paper with some general remarks upon research
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