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Aviation History
1936
1936 - 0294.PDF
132 FLIGHT. JANUARY 30, 1936. CORRESPONDENCE •lie Ldnor does not hold himself responsible jor Ihe views expressed by correspondents. The names and aidresses of the wxken, not necessarily for publication, must xn all cases accompany letters intended for publication in these columns. Commercial Efficiency " I SEE that Mr. D. W. Brown has compiled a list of the smaller civil aircraft, using my formula for "Commercial Effici ency." This may give the impression that the smaller types are more efficient than the large aeroplanes, but this is not necessarily so. J was, as stated in my article, comparing regular air line machines having luggage and lavatory accom modation—which, of course, take up space that might other wise be used lor passengers. The smaller civil types do not provide both of these ameneties and should therefore be able to tarry more passengers in proportion to their h.p. By using my formula, small aeroplanes tan be compared with each other and the air liners with each other; but when trying to compare the Iwo different types, allowance must be made for the difference in accommodation. Willi regard to your criticism, you will see, if you read my article, that the 190 h.p. I quoted is the rated output of the Gipsy VI and not the maximum power. Walton-on-Thames. E. N. B. BENTLEY. Genesis of Geodesy IN youi interesting article last week on geodetic construction, you state that many examples of it may be found outside the aircraft world. Reference to pre-war issues of Flight might show that the old German Schutte-Lanz airships were flying examples of "geodesy," for the description of a model of the S.L.i in the Science Museum includes the passage: "The structure con sisted of a number of circular hoops placed transversely across the hull and held in correct relation to one another by multi ply wooden girders arranged spirally." Certainly the appear ance of the model suggests a geodetic form of construction. It would be interesting to know whether, in addition to their other original improvements in airship design, the Schutte- Lanz concern used this type of structure. If so, it is amazing that, in common with such people as the firm of Junkers, they did not follow up the idea as Mr. Wallis has done. London, N.W.6. A. V. CLEAVER. [Our correspondent is correct in his assumption that a form of geodetic construction was employed in the Schiitte-Lanz airships; but to adapt it to the much higher and more localised loadings of heavier-than-air craft is a long step.—ED.] That Gliding Subsidy OWING to misleading statements in the Press regarding the Government subsidy for gliding and its distribution, it is due to the tax-payers of the country that a few of the facts she .' i be stated. The efforts made by those who were responsible for the post war revival in gliding in this country resulted in the Govern ment's decision to make the grant in aid of those clubs which had shown themselves effective but, nevertheless, were unable to carry on without aid. As soon as this decision was made the one club in the country which justifies the doubtful statement that " Glid ing is a sport for gentlemen" (i.e., for those of means), sought re-entry into the British Gliding Association (through which the Air Ministry was proposing to administer the grant), and so acted that the Air Ministry decided that the grant would only be paid through a united Association. Thus that club gained re-admission to trie Association, and it was agreed by both sides that those who had been in conflict should stand down from future negotiations. However, those in the re-admitted club did not keep to this agreement, as did those of the other side, and by this and other means this one club gained control of the re-organised British Gliding Associa tion and of the Committee set up within the Association to administer the grant. This unilateral Committee then drew up terms with which clubs had to comply before applying for grant, these terms being particularly favourable for the one club referred to, and certain conditions of application were included, under those qualifying terms, which were definitely exclusive. The result is that only two or three clubs have received State assistance. The one club which was not in need of aid hac taken more than half of the total amount available for clubs—^2,500 of the tax-payers' money to those gentlemen wh„-, owning their own high-performance machines, have put up performances which skilled provincial pilots are unable to approach because they are not allowed help for the pur chase of such machines and cannot afford to buy them privately. And it is on the strength of these performances that that club claims its efficiency. There are provincial clubs which can, in proportion, show a better record but which are now quite unable to get a penny of assistance. Conditions for claiming subsidy have been stated in the Press to be "simple." This really refers to the qualifications wi b which clubs must comply before submitting a claim, which are by no means simple—as the majority of the lead ing gliding clubs will maintain. But the " conditions" under which a claim may be put forward by a "qualified" club are restricted and absurd. The purpose for which the grant was made is, at the moment, utterly defeated. (Miss) R. H. SINCLAIR, Sutton Courtenay, Berks. Hon. General Secretary, Federation of British Gliding Clubs. The Burnetii Aerofoil Body IN The Aircraft Engineer supplement of Flight of December 26, 1935, there appeared an article entitled " The Burnelli Aerofoil Body." An explanation on our part regarding the origin, purpose and content of this article may be helpful. The subject matter was written by Dr. Michael Watter as a preliminary report in the course of his research of some under lying principles of our type of aeroplane. The artifice of the use of a hypothetical aspect ratio of the body was1 resorted to for the sake of expediency in an attempt to interpret the significance of the proper co-ordination of zero lift angles and to assist in a basic understanding of this problem. Since that time, Dr. Watter has made further studies of this problem based on the exact approach treating the body-wing combination as a distorted aerofoil, in which case no such artificial assumption as appeared in the article is required. In connection with these investigations considerable wind tunnel research was conducted, which confirmed all our pre dictions regarding uniform lift distribution and the extent of aerofoil body lift which amounts to 27 per cent, of the gross in the UB-14 type. This explanation is made because of the obvious criticism which may arise in connection with the simplifying assumption used in the article. Keyport, New Jersey. BURNELLI AIRCRAFT, LTD., VINCENT J. BURNELLI. Encouraging the Private Owner "TNDICATOR," in your issue of January 23, is, indeed, •*• as depressing as the weather. But, really, are things quite as bad as that ? It is true that, at the moment, the number of days on which flying is possible for the average amateur makes ownership a very expensive pleasure or con venience. In these circumstances, the sensible thing to do is to pay for an aeroplane only when you use it; in other words, to hire until the time comes when the better aeroplane is made. There is nothing against this ; a modern hire fleet gives the hirer at least as good a machine as he could buy and, m nine cases out of ten, one far better kept. He gets a machine kept for the purpose, not a second-hand machine awaiting sale, or a "school" machine not on its usual duty. Thus, there is no reason why the number of potent-al owners shall not be increased now, without waiting for the perfect machine. After all, the greater the increase in the number of potential owners (all pilots), the sooner will manu facturers be able to spend the large sums on experiment and development which alone can give us what is wanted. Heston. C. W. WRIGHTSOX In Brief The words "sinking in a partly slatted condition," which occurred in Fit. Lt. G. M. Buxton's letter on tapered wings »» Flight of January 16, have an unfortunately Bacchanalian air; what out correspondent actually wrote was "yet t"':r, is positive aileron action when sinking in a partly sta''ea condition."
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