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Aviation History
1928
1928 - 1129.PDF
DECEMBER 6, 1928 Lakehurst, New Jersey, on the arrival of the " Graf Zeppelin "to make a close study of the mooring of the airship. The progress Canada is making in aerial affairs along linesfollowed by other countries after having achieved a signal and unique development in the peculiar direction she adopted,is highly gratifying. The machine of the air now enters effectively into practically every phase of Canadian life and issteadily widening the scope of its influence. The progress of flying clubs throughout the Dominion has been highly encou- raging, and these have had a marked effect in extending theutilisation of the 'plane in Canadian life and in developing " airmindedness" in the Canadian people. The futurepromised for aviation in the Dominion is inducing an ever- growing manufacturing industry, which forecasts a definiteindependence for Canada in this field. The latest announce- ment along this line is that Fairchild 'planes, which havepreviously been manufactured under licence in Canada, will now be built in their own Canadian factory. AIR SURVEY AND EMPIRE DEVELOPMENT COL. H. L. CROSTHWAIT, C.I.E., R.E. (retired), gave aninteresting lecture on " Air Survey and Empire Development" at the Royal Society of Arts on November 27. Sir ThomasHolland was chairman. Col. Crosthwait said that the total area of the British Empire was nearly 14,000,000 squaremiles, and if they considered a country as surveyed if it was covered by £-in.-to-the-mile or larger scale maps, executedon scientific lines by an established survey department, they found that only about 20 per cent, of the whole area camewithin that category. Those figures showed how little had been done. As an instance of the omission to map thecolonies, we had been in occupation of Jamaica since 1655, just 273 years, yet there was not a single map of the islandof any value. One great disadvantage of the production of maps bynormal survey was its extreme slowness. By the use of air photographs it was possible to speed up the mapping. Theycould be taken at the rate of 80 to 100 square miles per day, which meant having down on paper all the topographicaldetails of the ground in extremely short time. All did not end there. Points had to be fixed on theground to form a framework to control photographs, both as regards planimetry and height. That framework in extentdepended on the nature of the country under survey, but certainly less ground work was required than in the case ofnormal survey. Then, the photographs required interpre- tation, object names had to be collected, and maps drawnand printed embodying detail derived from the photographs after reduction to the proper scale. All that progressedrapidly after the photographs were taken. From the fact that the photographs were taken from theair, it was not so material whether the country could be classed as easy or difficult for normal methods of survey.It was just as easy to photograph forest country from above as open spaces. Air methods involved minimum work onthe ground, and in unhealthy areas the ground staff was reduced and remained for the shortest possible time in thelocality. Col. Crosthwait then explained how air survey was carriedout. The given area was divided into suitable sections, whichwere covered by vertical photographs from an aeroplane flying along parallel straight lines, using the WilliamsonManufacturing Co.'s "Eagle" camera, which was capable of making 100 exposures on a single roll. The photographswere taken with a 60 per cent, overlap in a forward direction and about 30 per cent, overlap in a lateral direction. Afterdevelopment and printing they were roughly joined and given to field surveyors, who fixed suitable points for purposes ofcontrol, which could be easily recognised both on the photo- graphs and on the ground. They also classified objects such as roads and collected the object names required forthe final map. That fixing of points could be done by triangulation if thecountry was suitable, but often the areas were wooded and intersected by waterways, so that it was now usual to fixpoints by astronomical observations ; that was, determine their latitude and longitude by wireless time-signals, madepossible by the broadcasting of the Greenwich time-signals. A comparatively new instrument of French invention hadcome into use in this connection called the Prismatic Astro- labe, made by Messrs. Casella. There was also a surveywireless time receiver made by Messrs. Marconi. Another method had also been employed. Instead oftaking vertical photographs, oblique photographs were taken in such a manner that the horizon was visible in the picture.But it was not suitable to every class of country. The ground should be flat and the horizon visible when thephotographs were taken. The method had been largely used in Canada. Col. Crosthwait also explained other uses towhich air photography could be put in connection with economic development. It was extremely applicable to thelocation of railways in undeveloped or partially-developed countries, where either no maps existed or were of a smallscale only ; the object being to assist the railway engineer to decide the best economical line to construct. The faultyalignment of a railway might be the cause of considerable and continuous loss. Among engineering uses to whichair photography was applicable was the investigation of water-power development, water storage for irrigationpurposes, and allied engineering projects. It had been found that the feasibility of a water-power scheme, involvingstorage of large quantities of water, necessitating the sub- mergence of considerable areas of land, could be ascertainedfrom the study of air photographs in the stereoscope, with a very small amount of ground work. With regard to the relationship with economic developmentof new countries, continued the lecturer, Mr. R. Bourne, of the Imperial Forestry Institute at Oxford, had recentlybrought out a most interesting and important pamphlet dealing with the subject. In it he described the results ofhis investigations in Northern Rhodesia, using air photographs originally taken by the Aircraft Operating Co.'s expeditionin that country under Maj. C. K. Cochran-Patrick, D.S.O., M.C., for the Rhodesian Congo Border Concession,Ltd.who kindly allowed the photographs to be used. In conclusion, Col. Crosthwait remarked that for a surveyof a country to be really effective, and promote the interests of development to the fullest extent, it was necessary thatall Government departments should co-operate so that all information required by each one of them should result fromthe survey. 11 With Cobham Round Africa " WE referred the other week to the private view of a veryexcellent film, under the above title, concerning Sir Alan Cobham's survey flight round Africa in the Short-Rolls-Royce" Singapore " flying-boat. Although the general release date for this film is not until July next, the public now have theopportunity of seeing for themselves this remarkable record of an equally remarkable flight. It is now having a specialrun at the Pavilion, Marble Arch, and we thoroughly recom- mend all FLIGHT readers, who can possibly do so, to go andsee it, for, as we remarked before, it is not only one of the best aviation films we have seen, but it also scores as regardsa story of adventure, and as a study of nature, geography and pictorial effect. Air Malls THE Postmaster-General announces that, owing to thesuspension of certain connecting air services abroad, the Letter Air Mail Services to Denmark, Sweden and Norway,and the Air Parcel Services to Denmark and Sweden, have been suspended until further notice. Also, regardingColombian Air Mails, that as from December 1, the minimum charge of 10s. per parcel on parcels intended for transmissionby the Scadta air service in Colombia (South America) will be abolished, and the charge will be at a flat rate of 4s. %d.per lb. Air parcels can now be accepted for all places in Colombia.Air Mail Stamp Designs A SERIES of designs for air mail stamps is on viewat the headquarters of the Aero Club of France, in Paris. One or more designs are to be chosen for permanent use.The Royal Air Force Memorial Fund THE usual meeting of the Grants Sub-Committee of theFund was held at Iddesleigh-House, on November 29. Lieut.-Commander H. E. Perrin was in the Chair, and theother members of the Committee present were :—Mrs. L. M. K. Pratt-Barlow, 'O.B.E. ; Mr. W. S. Field ; Sqdn.-Ldr.Douglas Iron, O.B.E. The Committee considered in all 19 cases, and made grants to the amount of ^402 14s. Sd. 1035
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