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Aviation History
1912
1912 - 0886.PDF
[/yog] CORRESPONDENCE. Pressure Distribution on Planes. f 1631] I have read with great interest your notes on Mr. Handley Page's lecture to members of the Aeronautical Society on March 27th. I shall 1* much obliged if you will kindly inform me whether M. Eiffel's work has appeared in English translation and, if so, who are the publisher*. I must admit that I have been startled by the statement at the foot of page 402—that " the shaded area above the section is negath e pressure (suction)." Is that statement made on the authority of M. Eiffel. If so, it would lie interesting to know what steps he took to differentiate between pressures having positive and negative origin. If the diagrams, as explained by the statement which I have quoted, correctly represent the facts, it follows that by far the greater part of the lift in an aeroplane is due to vortex action on the back of the wing. This conclusion appears to be so much opposed to all that reason and observation suggest, that I venture to hope that you will be so good as to supplement your notes of this week by indicating the methods employed by M. Eiffel to determine the nature of the pressures. I venture, further, to add that, if you do this, you will place your readers under a debt of gratitude unequalled by anything since the publication of the Ilankin papers. I had convinced myself that the vortex as an efficient principle in flight could not stand, and I am sure that there are many others in the same state of mind to whom your notes must have come as a great surprise. Castlerea, Co. Roscommon. MAURICE J. DODD. [As desired, we deal with this subject on page 873.—ED. J SEPTEMBER 28, 1912. Gyroscopic Force and Accidents. 116321 Less than two hours before the accident that killed Paul l'eck I had a talk with him on the subject of the danger in gyroscopic force. lie admitted that at times this force had caused him considerable trouble, but said that he did not believe it to be particularly dangerous. I explained to him several conditions that would excite gyroscopic force in his motor to a point where it would become highly dangerous and told him that should he ever meet one of these conditions he would at once become convinced that I had not over-estimated the peril, but that he would then be in the same fix as the other fellows that have gone before, not able to tell about it. The newspaper accounts of the accident say " No one but l'aul I'eck could tell exactly what caused the accident." I had just examined Peck's new machine and told him that he would have to be extremely cautious in the use of its controls as it, in my opinion, would be highly susceptible to the elevator and would rock lightly about its lateral axis. You will notice by the newspaper accounts that after his first flight he spoke particularly atiout this very feature, and it was no doubt one of these sudden dips that excited gyroscopic force and caused the spiral movement in his machine. I found three eye witnesses, not one of whom was an aviator, who distinctly saw Peck turn his controls contrary to his path of flight, but in all the accounts of the accident given out by the aviators not one of them mentioned the fact that the machine spiralled with its rudder turmd to the outside of the circle Rod pitched downward with its elevator raised to the limit! Nor did anyone think it worth while to mention that during all this time the motor was spinning at top speed, yet these three features of the accident were completely ignored in all published accounts. Peck said that, while he did not believe there could be any great danger from gyroscopic force, he was open to conviction and asked me to bring out to him the following afternoon a copy of my new article on the subject. I was there with the copy at the appointed time, but too late. Chicago. THOMAS PRESTON BROOKE. Engine Cowls. [1633] The similarity in the lamentable disasters by which the lives of four brave officers of the Royal Flying Corps have recently been lost in the service of their country leads one to consider the question of any dominant features common to the machines flown, that might be contributory to these fatal results. Both machines were fitted with so-called " rotary " engines—more correctly speaking, engines with revolving cylinders having recipro cating pistons—and each machine was supplied with an open- mouthed hood or cowl to the engine. Anything more opposed to one's preconceived idea of a " stream-line entry " would be difficult to imagine. To enclose, or to partially enclose, a revolving mass of metal, a portion of which might become detached owing to centri fugal force is to offer facilities for it to jam the machinery. In each of these icgrettable accidents it is reported in the lay Press that, according to eye-witnesses, the engine "exploded," ^Zr^S^^^oUero^ne^Ue, with an open- mouthed engine cowl, despite the enclosed revolving cylinders air "enormously compressed within the open-mouthed hood which compressed air upon the aeroplane meetmg an, • air-pocket would immediately assert itself and might cause unstable eqmhbnum. Upper Tooting. J. F. SPONG. The X Constant. I" 1(5141 Kindly allow me to criticibe Mr. Berriman's constant X. The fact that the Bristol and Deperdussin monoplanes have values of X (anticipated flight speed m.p.h.) of 102 and 69 respectively. While the speeds actually obtained were of the order of 7c1 m.p.h. seems to sugeest that the Bristol was under powered. This does not seem to me to be the case as I consider the Br^tol s lack of flexibility of speed due rather to inability to change its position of flight than to low power. At any rate it has a good power margin for climbing. Now, a glance at photographs of the machines in question will show that, in flight, the angle of incidence of the Bristol is greater than that of the Deperdussin. A glance into the "Principles of Flight" will convince the unbelieving, if there be any such, of the important part played by the angle of incidence in the design of an aeroplane. I trust, sir, that you will reconsider the proposition you have set forth in the new light shed on the subject by due consideration of the angle of incidence. Liverpool. T. FITZGERALD. ® ® ® ® PUBLICATIONS RECEIVED. How to take out Patents in England and Abroad. By Arthur E. Edwards. London : Wyman and Sons. Price 2s. Catalogues. 1912 Aerial Maximotor. Maximotor Makers, 1526-1545, East Jefferson Avenue, Detroit, Mich., U.S.A. Everything Aviatic, including Aeroplanes, Motors, Parts, &*c. The Hamilton Aero Manufacturing Co., Seattle, Washington, U.S.A. "Aera" Specialities for Aviation. Aera, 16, Avenue de la Grande Armee, Paris. ® ® ® ® Aeronautical Patents Published. Applied Tor In 1011. Published September 56th, 1912. 20,229. P- BENNI. Automatic balancing of aerial machines. s°i572- j. L. GARSED. Treadle control for aerial machines. 22,407. A. E.j H. L. AND H. O. SHORT. Flying machines. 23,409. A. E., H. L. AND H. O. SHORT. I.C. engines. 27,625. G. MEES. Hydro-aeroplane. 29,117. A. DOUTRE. Aeronautical machines. PRINCIPAL CONTENTS —•— PAGE 868 Editorial Comment The War Office and the Monoplane. The Aeroplane in War. Hendon Second September Meeting 869 Hydrogen v. Coal Gas. By Griffith Brewer 871 Negative Pressure on Wings 873 Royal Aero Club. Official Notices 874 From the British Flying Grounds .. 875 The New 6-cylinder 100-h.p. Green Engine ... .. .. 878 British Notes of the Week , 879 Foreign Aviation News ... ... ... ... ... ... > 880 Airship and Balloon News ... ... ... 881 Ari Attempt to Invest»gate the Physical Properties of a Twisted Skein of Rubber. By W. W. Hastings Rider and Allan P. Hitchens, B. Eng. (Liverpool) 882 Progressof Flight about the Country ... 884 Models. Conducted by V. E. Johnson, M.A 885 Correspondence ' gs& FLIGHT, 44. ST. MARTIN'S LANE, LONDON, W.C. Telegraphic address: Truditur, London. Telephone : 1828 Gerrard. SUBSCRIPTION RATES. FLIGHT will be forwarded, post pee to any part of the world at the following rates:— UNITED KINGDOM. ABROAD. Months, Post Free if » s. d. 1 8 3 3 6 6 3 Months, Post Free... 6 >, „ 12 „ „ ... s. d. 2 9 S 6 11 0 886 2 12 Cheques and "Post Office"'Order*'should be made"payable to the Proprietors of FLIGHT, 44, St. Martin's Lane, W.C., and crossed London County and Westminster Bank, otherwise no responsibility will be accepted. T
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