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Aviation History
1922
1922 - 0062.PDF
oil used is considerably cheaper than petrol. The fuel consumption per horse power developed is low, so that for flights of long duration the engine can be somewhat heavier than the petrol engine and still leave as great a margin for useful load. Another advantage is that, as the air is forced to the cylinders under pressure, the blowers can be so arranged as to have, as in the Garuffa, a two-speed gear, which allows of developing maximum power for getting off the ground, and for flying at great altitudes. Against these advantages must be placed several drawbacks. For instance, there is the question of weight. This, however, it appears is not so serious as generally thought, and may possibly be overcome to a great extent. Then there is the problem of fuel pumps. We have heard from the Director of Research recently that petrol pumps as used for transferring petrol from one tank to another are still liable to give trouble, and possibly the fuel feed pumps of a Diesel type of engine would be subject to the same difficulties. Finally, in addition to the question of adequate cooling, the needle valves which admit the fuel, under a pressure which, must neces sarily be greater than the compression pressure in the cylinder, may prove a source of trouble as regards the proper amount of fuel admitted to each cylinder. If the fuel is unevenly admitted, the smoothness of running will be affected. However, the difficulties do not appear insuperable, and it is gratifying to know that the problems are being attacked vigorously. -> -9> * If we look back through the history of The Really the development of the ship, we find Large tnat t^e generai tendency, for craft oAhe intended for long-distance work at any Future rate, has been towards a constant increase in size. There came a time when it was thought that the limit had been reached, but this does not appear to be the case, and the development goes on, although more slowly. It may be admitted that, so far as can now be seen, there is little more to be gained in speed by surface craft, and it will be to aircraft that future generations will look for high speed of travel. It may not, therefore, be without interest to attempt to form a picture of the manner in which aircraft, and especially heavier-than- air craft, may be expected to develop. Here, as in the case of the ship, it is fairly certain that for long distance work the tendency will be towards greatly increased size. If we imagine a machine of about 50 tons total weight (and such a design has already been got out in Germany by Professor Junkers), with a thick, high- lift wing section, and assume a wing loading of 10 lbs/sq. ft., we arrive at a wing area of about 11,000 sq. ft. This high-lift wing will have a maximum thickness of about 18 per cent, of the chord. If, now, we assume a maximum chord of about 40 ft. in the centre, we arrive at a wing depth of about 7 ft. This means that there will be sufficient depth to place the engines, passenger cabins, tanks, etc., inside the wings, and it would therefore appear that it might be possible to suppress the fuselage altogether, or at any rate to reduce it to a couple of enclosed girders carry ing the tail. If we imagine a folding undercarriage which disappears into the wings during flight, we arrive at the conclusion that the L/D of the whole machine might be as high as 15 or so. As that of the average machine of today is only about 7 or 8, the gain in efficiency would be very great indeed, FEBRUARY 2, 1922 • reducing the power required by between one-half and one-third. The effect of this on the cost of air trans port would be considerable, and the whole subject of the " giant " is one of extreme fascination. Its day is not yet, but it is coming. •» • «. It might have been thought that, with for *thter *^e relatively few machines now being S.B.A.C. built, there would be no difficulty about procuring timber of the very highest quality. Yet this does not, from what we gather, appear to be the case. Wherever we go we are met with a general complaint regarding the practical impossibility of procuring good silver spruce. Even with the most careful selection of the planks there is a tremendous waste—on an average 50 or 60,per cent., and sometimes more. This means that not only is there the difficulty of making spars which are up to the standard required, but the expense is quite dispro portionate. One is at a loss to account for this state of affairs. The slopes of the Pacific coast are surely not stripped of all the good silver spruce trees ? That seems impossible. The explanation, it is alleged, is that the timber merchants have large stocks of timber still left over from the War, and this not of a very good quality, and refuse to import any more until present stocks are used up. If this explanation is the right one, it points to a serious state of affairs, and it appears to us to be eminently a matter for the Society of British Aircraft Constructors to take up. If the timber merchants really do take this attitude, there would appear to be nothing for it but for the S.B.A.C. to charter their own vessels and to import the timber direct. • * * -.r- ^ ^ Following the Government decision to Kingsnorth ,, J, , ,, , . , . for Sale scrap the lot, the various airship stations are gradually being entirely evacuated, or the personnel reduced to care and maintenance parties. Among the latest airship stations, although described by the Disposal Board as a Kite Balloon Station, to be advertised for sale, is Kingsnorth, near Chatham. This station com prises about 600 acres, and already has a number of buildings and one large airship shed. In view of its location, and with the existing facilities of railway connection to Sharnall Street Station on the S.E. & CR. and its jetty on the Medway, it would appear that Kingsnorth is admirably suited as a terminus for* airship services when and if such are started. It therefore appears a somewhat doubtful policy on the part of the Government to offer this site for sale just now, as it could quickly and with but small outlay be got ready for serving as the London " port " for airship services. The erection of a mooring mast and a few other additions to the existing equipment would be all that was required, the ships, of course, going" to a suitable base, such as Pulham, for repairs and overhaul, much as a steamer now goes into dry dock. Kingsnorth would appear to be much more suited for the purpose than is, for instance, Croydon aerodrome, and we would urge upon those in authority to consider the advisability of retaining Kingsnorth for a time at any rate, so that if, as doe's not seem improbable, airships are to be given a chance, the station is available as a small beginning during the experimental stages. Later, if it be found that the services grow to such an extent as to require other arrangements, the authorities would be no worse off through having retained the station. 62
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