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Aviation History
1914
1914 - 1029.PDF
OCTOBER 9, 1914. light covering ; the motor rod is a Jin. square piece of maple, and is 3 ins. long, and is stayed up in the usual manner with a king post in the centre. The centre of gravity of the machine is situated just behind the front spars." Our correspondent, who invites criticism on the above, inform* us that he intends to experiment a great deal with this type of model—a fact which we note with much pleasure. Messrs. J. Bonn and Co.'s New Disc Wheels. We have received from the above well-known firm a pair of their new disc wheels, for model aeroplanes, &c, with the request that we put them to any test we like, for the purpose that is for which they are intended ; the makers being quite sure that they will emerge triumphant. They are certainly in every respect vastly superior to anything else we have hitherto seen in this line, both as to design and neatness of finish, and are extraordinarily strong ; they weigh 7 grammes (about J 02.) the pair, they have a broad fiat rim, and are sufficiently strong to land quite large models ; the parti cular pair sent have a diameter of 1*5 ins. The price is 2d. each. Under present circumstances it is especially gratifying to note that they have been manufactured throughout by Messrs. Bonn and Co., who have made special tools in order to manufacture them and supply them wholesale to the trade as well as to individuals. Messrs. Bonn and Co. state that wheels of this description have hitherto been supplied from the Continent, from whence (as so many aeromodelists know! has come a fearful lot of aeronautical rubbish. It is, however, only fair to state that this year (up to the commencement of the war) it had shown, in not a few ways, considerable improvement, and there is no doubt that ere long British model firms would have found the competition very keen. Special attention abroad was being devoted to compressed-air motor plants, more especially to the placing on the market of a complete plant for a pound to thirty shillings which should have a good appearance and work well (for a time). Apart from its frailty and insufficiently good workmanship to stand any really rough usage, the greatest fault of such plants was "leakage"; but they were selling well, because there are plenty of model workers about who would sport one guinea over such a plant, but would hesitate a long time over one costing at least three, even if they were able to afford it at all, and yet we do not see how a really satisfactory plant can be turned out under. If any British firm can do it, so much the better—there is certainly an opening for such. To return to the case in point, these disc wheels are not only vastly superior to their former ^foreign competitors, but they are no dearer—a fact which is bound to appeal more or less to all. The B.G. Lubricant. Some time ago a tube of the above was handed to the writer for the purpose of testing the same and reporting on it. It is, however, only quite recently that an opportunity has arisen for making any experiments with it. The following claims are made for this lubricant : that it tends to preserve the rubber, keeps moist almost indefinitely, and that 75 per cent, more turns can be given than without its use. With regard to the first claim, all lubricant vendors make it, but we must say that we have never come aoross any lubricant or, for that matter, anything which enables you to use old rubber—last year's, for instance—for record making in the present year. Lubricants can, no doubt, be said to "preserve" the rubber motor in this way. Let us assume we are using a rubber motor which we can safely wind again and again to 400 turns unlubricated and 700 if well lubricated. Obviously, we could not use it again and again to 700 unlubricated; in this manner, then, it may be said to " preserve " the rubber. This is not all, however. Some lubricants have, we know, a deleterious effect on rubber, and in the course of a few weeks even, the rubber is rotten. It is only fair to state that such mostly, if not entirely, belong to the past. If we have a lubricant which has, so far as we can tell, no deleterious effect on the rubber, and which permits us to obtain a very considerable increased number of turns, we should, I think, rest satisfied. If, in addition to this, the lubricant keeps moist for a long time, and has no tendency (like some lubricants) to stick the strands together after use, then we have a lubricant of yet greater value. Our experience with the above lubricant, we are glad to say, bears out the above. The fact that we had the tube in our possession a good many months before using it also shows that it keeps well, which is still another point in its favour. In one case the lubricant was used on a rubber motor driving a model submarine, the rubber motor working in the water ; the lubricant was especially successful in this particular case. la order to increase Its elasticity, the pure rubber must be vul canised before being made into the sheets, some 60 to 80 yards in length, from which the rubber threads are cut; after vulcanisation (/yGHT) the substance consists of rubber plus some three per cent, of sulphur. Now, unfortunately, the presence of the sulpher makes the rubber more prone to atmospheric oxidation. Vulcanised rubber, compared then with pure rubber, has but a limited life. And it is, as already stated, to this process of oxidation that the more or less rapid deterioration of rubber is due. It is obvious that to preserve rubber it should be kept from the sun's rays, in a cool place, at as even a temperature as possible, because great extremes of temperature are very harmful to rubber. It has more than once been suggested to the writer that it should be kept in water. The drawback to this, however, appears to be G. Carter's Olympia model. that although rubber is quite insoluble in water, it will absorb no less than 25 per cent, of water into its pores after soaking for some time. This would have to be squeezed out before using. So far I have not personally found any better method than keeping it in a fairly large air-tight tin, in a cool place. The chemical composition of the best Para rubber is carbon 87-46 per cent., hydrogen 12 00 per cent., oxygen and ash 0^54 per cent. Benzol, petroleum, ether, volatile oils, turpentine, naphtha, vase line, soap and copper (both the metal, oxides and soluble salts) LCNQTH JB TftACTOR ) *i ii'omercH ("-— r T n 0 TRACTOR fNPLANL BY T. G.CARTER SC/M-E x * a « 10 « iMCMta Drawing to scale of Mr. F. 1029 G. Carter's tractor biplane model.
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