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Aviation History
1924
1924 - 0122.PDF
1/MrfgSsrJ Major Griffiths put in a considerable amount of work on this problem, and devised a method which is outlined in the Geographical Journal, which was comparatively rapid and worked very well. . . . The prints of the Cambridge area were eventually made into a mosaic showing the whole of the 225 miles of country, and this was adjusted to fit the positions of four control points which formed a rough square with 10-mile sides. Having completed the work, the position of the points shown on its various parts was carefully com pared with the position of the corresponding points as shown on the ordnance survey map. And it was found that the maximum error of position was never greater than 130 yards, while the errors were generally less than 60 yards. This is a surprisingly good result, since in part of the area the ground was 400 ft. above its level in other parts. Such an area is negligible for practical purposes in reconnaissance maps, say, on a scale of 1-40,000, and is frequently exceeded by the error produced by the change in the dimensions of the paper when an accurate map ig mounted on canvas." The author here briefly described an experiment, as yet unfinished, in surveying a large tract of land rich in timber in the Far East. " In the course oLthe Far East experiments, Griffiths had materially assisted in developing a scheme of aerial survey applicable especially to large unexplored tracts of flat country. While possessing the same general characters that had been used in war surveys, it differed in several important respects, viz., that the probable error at each stage was known, the special precautions needed to secure accuracy had been studied, and the instruments which might facilitate the work had been tested. Aerial survey based on vertical photographs was previously empirical ; it had now become a systematised science. It is for that reason that I venture to think that the work accomplished has in reality a far greater value than might at first appear, and I am in a position to make this observation owing to my experience in the earliest air surveys on a large scale. " I must again point out that while much of Cambridge work applies only to flat or comparatively flat countries, and is inapplicable to regions with high mountains, nevertheless it contains many elements which will be of value in the development of methods of survey in such districts. We in England can do little in the investigation of the problems of air survey among mountains, where vertical photographs FEBRUARY 28, 1.924 can only be of local application, but as far as \ve have had opportunities for research, I believe they have been employed usefully. Aerial Survey and Our Knowledge of the Surface of the Earth " I have indicated above one of the main lines along which the development of aerial survey is proceeding, and the other method of work through the employment of oblique photo graphs has been mentioned. " Both these methods are being used in practice in Canada, where aerial survey, fostered by Dr. E. Deville, Director- General of Surveys, seems to be in a flourishing condition, though still in the experimental stage." " Of the two methods referred to, I have myself been mainly interested in the first, and I wish now to try and show why I consider it of such interest and importance. In large stretches of featureless and uniform country the oblique method may possess many advantages, but in other areas the portrayal of the ground in the fullest detail may be of greater utility. " I think it may reasonably be said that as civilisation and the utilisation of the earth's surface by man proceeds, so a more detailed knowledge of the earth's surface becomes necessary. In former years, maps showing the general features of the earth, such as the main divisions between land and water and the principal mountain ranges, were quite sufficient for man's needs. Then in civilised regions more detailed maps on a scale of about 1 in. to the mile were needed, in which greater detail was shown. But as time passes we need to know more and more detail about our countries, especially as they are opened up by communica tions, as cultivation, irrigation, mining and forestry opera tions are commenced upon them. Thus the ideal survey is the one which provides the greatest possible amount of information, obtained with accuracy and despatch. " Within the period of the Great War the same principle was illustrated in a marked way. The wealth of detail required for the operations in its concluding stages was infinitely greater than what was deemed necessary during the first year. Even in a campaign like that fought in Palestine, the exact knowledge of the contours of the country at every point along certain roads became of vital importance to the plan of operations, instead of a general knowledge of the direction in which those roads ran. (To be concluded.) ROYAL AERONAUTICAL SOCIETY Official Notices Election of Members.—The following Mem bers have recently been elected :— Fellows : J. H. Parkin, J. D. Siddeley. Associate Fellows : Flight - Lieut. N. Comper, F. J. W. Wingfield Digby, A. A. Quayle, A. H. Leak. Students: B. Howard, G. Lvon, R. J. Moffett, R. W. Symmons. Member : T. A. Gladstone. Associate Member : A. G. Lamplugh. Foreign Members : Major N. Brearley, R. T. Hurley. Journals.—The , February number of the Journal of the Royal Aeronautical Society contains " The Thermo-Dynamics of Aircraft Engines," by H. R. Ricardo, and "The Aero dynamical Characteristics of the Airship as Deduced from Experiments on Models" (" R.38 " Memorial, Prize Paper), by R. Jones. Lecture.—The next lecture will take place at 5.30 p.m. on March.6, at the Royal Society of Arts, 18, John Street, Adelphi, when Major Tucker, RE., of Woolwich Arsenal, will read a paper on " Sound Reception." Annual General Meeting.—The Annual General Meeting of voting Members of the Royal Aeronautical Society will be held at 7, Albemarle Street, at 5 p.m. on March 27. W. LOCKWOOD MARSH, Secretary m m m m The Royal United Services Institution and Aviation ON February 20 Air Commodore R. H. Clark Hall, read a paper before the above. Institution on " The Value of Civil Aviation as a Reserve to the Royal Air Force in the Time of War." Air transport lines, the lecturer stated, would form the backbone of civil aviation, but they must be subsidised until they became a commercial proposition. At present civil aviation could not constitute a reserve, as it was not large enough, and it was not large enough because it did not pay. There were three stages in the progress of hew inventions for increasing rapidity of communication—experiment, accompanied by scepticism, ridicule, and opposition ; develop ment in the form of reliability and economical working ; and then expansion. We had now got over the stage of ridicule.'and were in the development stage, which, he thought, would end in its being a valuable reserve for the fighting Service. Aero Golfing Society THE Winter Meeting will take place at Coombe Hill Golf Club on Thursday, March 6, 1924, for the Challenge Cup presented by Sir Samuel Instone. The following players have so far entered :—Lieut.-Col. J. T. C. Moore-Brabazon, M.C., MP., Sir Henry White Smith, C.B.E., Air Vice-Marshal Sir Vyell Vyvyan, K.C.B., D.S.O., Lieut.-Col. F. C. Shelmerdine, O.B.E., Flight-Lieut. D. FitzGibbon, Capt. A. Newman, Major R. H. Mayo, A. J. A. W. Barr, Commander W. Briggs, P. Barry, F. Cumbers, R. Felgate, E. N. Clifton, H. Burroughes, Lieut.-Commander H. E. Perrin. A.D.C. takes over Martinsyde Aircraft. WE learn that negotiations have just been completed for the purchase, by the AircrSft Disposal Company, Ltd., of Regent House, Kingsway, of the manufacturing rights, good will, stock, &c, of Martinsyde aircraft of Woking. It is, of course, well known that the A.D.C. has done a great deal of business with Martinsyde machines, large numbers of which have been supplied to different countries. By purchasing the manufacturing rights of Martinsyde aircraft, the A.DC. will be able to continue and maintain the very high standard of efficiency and the good name which these machines have always held in British as well as in foreign air services. We gather that it is the intention of the A D.C. to take up original design and construction, and the stocks, plant, &c, will be transferred from the Woking works to the large A.D.C. factory at Waddon, Croydon, where future work will be carried on. Supermarines for Spain THE 12 aeroplanes which the Spanish Royal Naval Air Service decided to purchase from Great Britain, as reported in FLIGHT for February 14, are, we understand, a new type of supermarine amphibian flying-boat. 122
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