FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1912
1912 - 0982.PDF
4i lbs. has been overcome through a distance, b a. It seems obvious reasoning that the air has been thrown upwards by the action of the plane, and that the action, having been derived from the plane, there must be an equal and opposite reaction on the surface of the plane itself, so that lifting effect cannot result. The matter does not, however, rest at that. There is no increased lift, but there is very considerable increase of drift. The pressure of the outside air exerts itself in directions normal to the curvature of the limiting film, so as to flatten it out so to speak, and bold it tight down against the surface of the aerofoil. From the character of the curve it will be seen that the resultant must be well forward and that it must have a rearward sense, something like that indicated by the heavy line and arrow. M. Eiffel's method, so far as I can ascertain, was to measure the atmospheric pressure at different points on the back of the surface. While there need be little doubt of the correct ness of the methods he employed for bis purpose, it is wrong, I think, to conclude from the results he obtained that vortex action takes place with all aeroplanes, and is, in fact, a desideratum. Our experience goes to show that aero surfaces of flat camber are the most efficient. We find that when we use more highly cambered surfaces there is loss of efficiency, more power absorbed without a corresponding gain in useful work. Where has the power gone to ? It must have been absorbed somewhere. It seems clear to me that it has been absorbed in the useless work of creating a vortex on the back of the surface, and in endeavouring to overcome the increased resistance which the vortex opposes to passage through the air. We have experimental proof of this fact, and the most convincing experiments I have read of are those of Sir Hiram Maxim, rendered more convincing perhaps by reason of the fact that at the time Sir Hiram would not admit the possibility of the air taking such a course over the back of the plane as that suggested by the experi ments of M. Eiffel. He held the view that with properly constructed surfaces the air follows the upper and lower sides, and leaves at the back at an angle equal to the resultant of the angles of trail for the upper and lower surfaces. This is, I believe, true of aero-surfaces of perfect efficiency, and these are not easy to build. Sir H. Maxim's experiments show that efficiency decreases with aeroplanes or pro pellers of coarse camber and pitch ; that is when we get the conditions favouring the formation of vortices on the backs of the aeroplanes or blades, as the case may be. MAURICE S. DODD. Castlerea, co. Roscommon, September 28th. [The interest and importance of Eiffel's curves are that they show the distribution of the pressures over the surfaces. The lift of the plane as a whole is due to the downward deflection of air in bulk, but this broad principle does not throw any light on the detail mechanism by which the acceleration of the air en masse com municates its reaction to the wing. Obviously, however, it must press upon the under side and pull upon the upper side. So much, at least, is no more than common sense would reason—Eiffel's curves show the distribution of the pressure and the tension (negative pressure).—En.] Brakes for Aeroplanes. [1659] Referring to the letter of Lieut. E. R. Knox-White (1647) appearing in your issue of October 12th, wherein he inquires if any kind of brake has been discovered for aeroplanes, perhaps you would be good enough to inform your correspondent that the writer has designed an aeroplane brake (patent applied for), and if he desires any further information perhaps he would communicate with me direct. " Salisbury," Church Hill, Walthamstow. V. H. MAIR. ® ® ® ® Aeroplanes at the 'War. THE various nations which are actively concerned with the conflict in the Balkans have made and are still making what arrange ments they can to see that their forces are equipped with aeroplanes and air scouts. Most of the Balkan States have had the foresight to have some of their officers trained as pilots, while others have secured the services of flyers of other nationalities. Servia has engaged Emile Vedrines, who is taking a 70-h.p. Deperdussin to the front, and Jules is also credited with going to the front. About the first real use made of the " fifth arm " was on the Friday week when a Greek aeroplane made a reconnaissance along the frontier, bat failed to discover any of the enemy. On Tuesday last a Bulgarian air scout started from Mustafa Pasha and flew over the Turkish forces in the direction of Adrianople. On sighting the aeroplane the Turks opened fire, but the aviator quickly elevated and escaped out of range. After half an hour's reconnaissance he is reported to have returned to headquarters with valuable information as to the disposition of the troop?. OCTOBER 26, 1912. ARMY AIRCRAFT IN PARLIAMENT. ON Wednesday in the House of Commons Mr. Tennant, replying to Mr. Joynson-Hicks, said that 361 men were employed at_ the Royal Aircraft Factory, all on experimental work, or the repair or reconstruction of service aircraft. No men were employed in manufacturing new aeroplanes. Thirty-six effective aeroplanes were in the possession of the British Army, of which twelve were at the Central Flying School. Of these, nineteen weie of English manufacture. In addition four machines were under reconstruction at the Royal Aircraft Factory. As a result of the recent competition valuable information as to suitable types of aeroplanes for military use had been obtained, but the Army Council did not propose, at the present stage, to decide upon any particular type for exclusive use. As regarded monoplanes, a scientific committee was now considering certain structural questions, and monoplanes would not be used in the military wing until the committee had reported. The number of officers and men enrolled in the Army branch of the Royal Flying Corps was :— Officers: Gazetted, 24; appointed, but not yet gazetted, 6; accepted, but not yet appointed, 93 ; non-commissioned officers and men, 440; making a total of 123 officers and 440 non-commissioned officers and men. Of the latter, 173 had not yet been fully enrolled. Pilots : Officers, efficient military pilots, 23 ; undergoing military training as pilots, 28 ; with Royal Aircraft Corps certificate only, 40 ; non-commissioned officers and men, second-class pilots, 6 ; making a total o( 97. ® ® ® ® A New American Record. ON the 6th inst., Lieut. J. H. Towers, on his Curtiss hydro aeroplane, beat the American duration record, remaining in the air for 6h. 10m. 35s., most of the time flying over Chesapeake Bay. His average height was 600 ft., while the greatest altitude was 1,200 ft. The previous record was the late Paul Peck's 4I1. 23m. 38s. on a Columbia biplane. Mr. Perry in the Tagus. WHILE Mr. Copland Perry was taking the Avro aeroplane just purchased by the Portuguese Government through its 80-min. test on the 17th inst., the petrol supply failed and a sudden landing had to be effected in the shallow water of the Tagus. Pilot and passenger were unhurt, and the only damage done was the breaking of a propeller. The Aerial League Dance. Mr. A. J. A. WALLACE BARR, on behalf of the committee making the arrangements for the dance held at Richmond Central Hall on Thursday, wishes to apologise to all those to whom he was- unable to send tickets. It is hoped to arrange another dance shortly, when a larger hall will be taken. Primus Policies and Importance of the Full Stop. JUST by the omission of a full stop in the advertisement manu script of Messrs. Bray, Gibbs and Co.'s announcement in last week's issue re their *' Primus " policy, it was made to appear that this aviation policy included breakages, motor, employers' liability and every kind of insurance. As a fact, it should have indicated that the policy includes breakages, while the firm also undertake motor, employers' liability and every other kind of insurance business. ® ® ® ® Aeronautical Patents Published. Applied for in 1011. Published October 24th, 1912. 23,278. J. WULFFING AND P. W. SMITH. Air-ship sheds. Applied for in 1013. Published October 24th, ig'12. 6,79s. LEDUC, HEITZ AND CO. Treatment of fabrics for aeroplane wings, &c- I5)735- J- K* PORTER. Propelling aeronautical machines, &c. FLIGHT. 44, ST. MARTIN'S LANE, LONDON, W.C. Telegraphic address : Truditur, London. Telephone : 1828 Gerrard- SUBSCRIPTION RATES. FLIGHT will be forwarded, post free, at the following rates:— UNITED KINGDOM. ABROAD. J. d. s. d. 3 Months, Post Free... 3 9 3 Months, Post Free... 5 o 6 „ „ ... 766 „ „ ... 10 o 12 „ „ ... 15 0 12 „ „ ... 20 o Cheques and Post Office Orders 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. 932
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
