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Aviation History
1910
1910 - 0318.PDF
JGGHT] APRIL 23, 1910. for him the Lornsquit prize. Aubrun was also flying on his Bleriot. and Valleton took up a passenger for a short trip on his Farman. It is proposed to organise another flying meeting to be held at the end of May, at which the prizes will amount to about ,£7,000. Developing Inventions. P«£ THE " A.I.R." Co., successfully launched last week,and of which the full prospectus was published in our issue of April 9th, evidently fulfilled a public necessity, as we are informed by the secretary that already 60 inventions have been submitted for the approval of the various committees. A New Wire Tightener. IN the accompanying sketch is seen a very neat wire tightener, known as the " Raid," which is being placed upon the market by Messrs. Eyquem's Patents. It is made of steel throughout, and a feature is that no lock-nuts are required, the screws being secured by split-pins, which pass through the centre slot. This arrange ment is very neat and also quite effective, while the elimination of all lock-nuts renders it possible to make adjustments in minimum time without any bother. Airship Garage Collapses at Munich. A BAD accident occurred on Thursday of last week at Munich, when the garage in course of construction for the Parseval airship, which it is proposed to use for aerial excursions, collapsed. Two lives were lost, and eight other workmen were very severely injured. The disaster is attributed to faulty foundations and to the construction Correspondents asking questions relating to articles which they have read in FLIGHT, would much facilitate our work of reference by giving the number of the letter. NOTE.—Owing to the great mass of valuable and interesting corre spondence which we receive, immediate publication is impossible, but each letter will appear practically in sequence and at the earliest possible moment, TESTING AERIAL PROPELLERS. 470] In pursuing a research in connection with aerial pro pellers, I have realised that models and small propellers do not afford sufficiently trustworthy data upon which to found serious •conclusions, and that trials of various types and designs, carried out on a full working scale, are desirable. On the occasion of the recent aerial show, accordingly, I issued a short circular in which I offered to test full-sized aerial propellers in a special installation I had lately set up at one of the London Polytechnics, and several makers and owners have availed themselves of the opportunity thus presented of learning the actual thrust and general efficiency of their propellers, at varying speeds and expenditures of power, as ascertained under severely scientific conditions. The apparatus employed comprises an electro-motor working up to 24-h.p. at 1,050 r.p.m., mounted, together with a headstock, or bearing, carrying the propeller-shaft, upon a substantial platform swinging from the roof of a building. The power absorbed at various r.p.m. is measured by standard electrical instruments ; the thrust effected (up to 300 lbs.) is read directly from a spring- balance ; and the speed of rotation is observed by means of a tachometer. The propellers so far tested include one furnished by the War Office, which had driven their dirigible balloon in its memorable voyage from Farnborough and across London. The tests themselves have been very interesting, for although it has happened in some cases that the efficiency has fallen short of what was predicted, it has been found sometimes that " the builders have builded better than they knew," as pressure-power curves have been obtained, which have ranged beyond what was expected. Lately, too, an Additional point of much importance has received attention, and the different velocities of the air set in motion at various parts of the area swept by the propeller have been carefully measured by an anemometer. On plotting curves from the data furnished by these various investigations, reflections and suggestions of a most valuable character present themselves to all concerned. of the building being hurried too much. As a consequence, the commencing date of the excursions has been indefinitely postponed. Prince Henry in " Kiel I." THE dirigible, " Kiel I," built by Herr Steffen, made its third trial trip on the 13th inst., when Prince Henry of Prussia was among the passengers. Aerial Torpedo Experiments with "Gross III." DURING a recent long-distance flight the military dirigible " Gross III " carried out some experiments in the discharge of explosives in the form of aerial torpedoes, and in view of the results obtained the experiments are bsing continued. A Balloon for the Pageant Master. MR. FRANK LASCELLES, who is the master of the forthcoming pageant at the Crystal Palace, is to be provided with a novel conning - tower, for it has been decided that a captive, balloon shall be acquired, and from this the pageant master will direct the move ments by means of telephone communication and megaphone. Balloon Struck by Lightning. A PECULIAR catastrophe overtook a party of balloonists who ascended from Bitterfeld, near Berlin, on Saturday last. At the start fine weather prevailed, but after about five hours' sailing, when the balloon was over Eisenach, it encountered a thunderstorm, and a little further on apparently was struck by lightning. This caused the gas to explode, and the car of the balloon fell like a stone to the earth, killing the four occupants instantly. The passengers were Herr Luff, of Bitterfeld, Herr Leuchsenring, manager of the Parseval Airship Co. at Munich, and two residents of Leipzig. No fee is expected in respect to making the tests ; the owner of the propeller, moreover, is invited to be present and himself observe the results. The figures obtained are, of course, regarded as private and confidential if so desired, but it is hoped that the general fund of information may eventually be increased by means of contributions to the Press. As the carrying out of these tests interferes to some extent with the prosecution of other serious work, I hope that correspondents will communicate with me immediately. Propellers (up to 7 ft. diameter only, at present) must be sent direct to the South-Western Polytechnic, Manresa Road, King's Road, Chelsea, but letters should be addressed to me as below. I should add that the face-plate at the end of my shaft is drilled and tapped to take a i-in. bolt, and that the cost of any special fitting must be borne by the owner. If a certified report of the test, illustrated by plotted curves, as mentioned, is required, a moderate fee will be charged. 93, Belsize Lane, Hampstead, N.W. J. A. MAYS. April 13th, 1910. FLYER DIMENSIONS. [471] I wish to call your attention to the fact that the authors of " Design and Construction of Aeroplanes " have made two errors in their tables of aeroplane dimensions, namely, with reference to the Wright biplane, of which the h.p. is stated to be 15, and also to the smaller Bleriot monoplane, where the writers seemed to have confused the cross-Channel type with another and larger machine, and in others the dimensions given differ from those I have seen, but which are right I do not know. Mr. W. S. Flight, in to-day's issue, states that the speed of the Dumont monoplane is only 40 m.p.h., but surely this is under-estimated. According to Mr. Flight's efficiency formula, comparative smallness of area heightens the efficiency of the machine, which is surely not as it should be, for, as Sir Ray Lankester has pointed out in the Daily Telegraph, the smaller the actual size of the object the greater the relative density of the medium which surrounds it. Therefore, in a given medium a small object is more readily supported than a larger one of the same form, so that a man who flies a large aeroplane accom plishes a more difficult feat than a person who pilots a small one. I wonder whether the horse-powers of the respective engines are calculated by the same formula, but perhaps someone can enlighten me on this point. Willesden. DAVID LUCKING. ® ® ® ® CORRESPONDENCE:. *,* The name and address of the writer (not necessarily for publication) MUST in all cases accomfany letters intended for insettion, or containing queries. 316
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