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Aviation History
1909
1909 - 0135.PDF
MARCH 6, 1909. CORRESPONDENCE. *»* The name and address of the writer (not necessarily for publication) MUST in all cases accompany letters intended for insertion, or containing queries. Owing to pressure on our space, several letters have been held over. OLYMPIA AERO EXHIBITION—A SUGGESTION. To the Editor of FLIGHT. •;•. ••-/" ;: : :. : • SIR,—Being one of the three non-trading, or private, exhibitors of full-sized machines mentioned in your other journal, Antomoior—my stand numbered 38 at the forthcoming International Exhibition—I shall be very pleased to include one of Mr. Sidney Hollands' 8-ft. propellers in my exhibit by affixing same to machine. I do not know Mr. Hollands personally, but his name is familiar enough to myself by his lectures at the Aeronautical Society meetings ; and I know, furthermore, that his propeller is based on sound scientific principles, and, indeed, has advantages that will prove much to render the helicoptere a practicable machine. I have forgotten Mr. Hollands' address. May I suggest, additionally, that I shall be happy to assist any aeronautical motor engine firm, such as the Miesse, by including, without charge, one of their engines on my machine, as my own engine will not be completed to my liking in time. Personally, I think we all should help each true worker one amongst another in the young science. If the above will kindly write me c/o Secretary, Motor Manufacturers and Traders, Arundel Street, Strand, he will no doubt forward same. Yours sincerely, EDGAR WILSON. Sea. They have a clear run.on level pasture land from one to two miles, on which they may have trials free of charge. We are, yours truly, 32, Charing Cross Road, S.W. HESTER AND HESTER. MORE FLYING GROUNDS. •'• . . : To the Editor of FLIGHT. SIR,—As we are very much interested in aerial flight, if any of your readers or friends who have aero-flying machines would like to try them, we should be glad to let them have the use of one of our small islands or farms at New Burnham-on-Crouch and Canvey-on- A MODEL ENGINE DESIGN. To the Editor of FLIGHT. SIR,—Re the model engine as mentioned by Mr. Potter in. FLIGHT, February 27th. The design of this engine alone is conducive to excessive friction. In the first place, friction is practically independent of speed and) the amount of surface in contact, being proportional to the pressure only. Now, assuming that the same sized cylinder is placed on a crank type of engine (which can be balanced, and vibration in reciprocating parts counteracted and practically absorbed as in modern high speed engines, this being a great point for use in aero- planes), the same pressure is applied at a point of greater leverage than is possible on an archimedean screw unless excessively large in diameter. Now, assuming that the point of leverage is four times, greater in a crank than in the archimedean screw, this would mean that four times the pressure would be applied to the surface of the screw than would be applied to the surface of a crank-pin to obtain the same turning effort, and it is obvious that four times the friction results. This without considering the increase of friction by use of a wedge action (from which greater friction always results), friction from end-thrust on the driving-shaft, extreme difficulty of lubrication, and excessive vibration from the increase of reciprocating weight. If steam or compressed air users concentrate themselves on the production of a light boiler or container, the engine can be left out of consideration, providing it is as light as can be made of its type and is efficient. As a practical engineer, I should certainly charge more for the screw engine than for the ordinary type, owing to the difficulty of making archimedean screws without special plant. Mr. Potter's engine is very ingenious, but I fear would prove fax less efficient than an engine of ordinary type. With apologies to Mr. Potter for my practical criticism, ' I am, yours very truly, MONTFORD KAY. PRESENT STATUS OF MILITARY AERONAUTICS. By GEORGE O. SQUIER, Ph.D., Major, Signal Corps, U.S. Army. (Continued from page 123.) J The " Republique - (Fig. 3.) THIS is the latest of the French military dirigible balloons, and differs but slightly from its predecessor, the " Patrie." The volume has been increased by about 2,coo cub. ft. The length has been reduced to 200 ft., and the maximum diameter increased to 35J ft. The shape of the gas-bag accounts for the 2,000 additional cubic feet of volume. The motor and propellers are as in the " Patrie." The total lifting capacity is 9,000 lbs., of which 2,700 lbs. are available for passengers, fuel, ballast, instruments, &c. Its best performance was an 125-mile flight made in 6J hrs. against an unfavourable wind. The material for the gas-bag of the new airship was furnished by the Continental Tyre Company. It is made up as follows :— Weight. Outer yellow cotton layer ... 3-25 ozs. per sq. yd. Layer of vulcanized rubber ... 3 '25 ,, ,, Layer of cotton cloth ... 3-25 ,, „ Inner layer of rubber ... 0*73 ,, ,, Total weight ... 10*48 It is interesting to note the changes which this type has undergone since the first one was built. The " Jaune," constructed in 1902-03, was pointed at the rear, and had no stability plane there; later it was rounded off at the rear, and a fixed horizontal plane attached. Finally a fixed vertical plane was added. The gas-bag has been increased in capacity from 80,670 cub. ft. to about 131,000 cub. ft. The manu- facturers have been able to increase the strength of the material of which the gas-bag is made, without materially increasing the weight. The rudder has been altered somewhat in form. It was first pivoted on its front edge, but later on a vertical axis, somewhat to the rear of this edge. With the increase in size has come an increase in carrying capacity, and consequently a greater speed and more widely extended field of action. "Ville de Paris" (Fig. 4). This airship was constructed for M. Deutsch de la Meurthe, of Paris, who has done a great deal to encourage aerial navigation. The first "Ville de Paris" was built in 1902, on plans drawn by Tatin, a French aeronautical engineer. It was not a success. Its successor was built in 1906, on plans of Surcouf, an aeronautical engineer and balloon builder. The gas-bag was built at his works in Billancourt, the mechanical part at the Voisin shop, also in Billan- court. The plans are based on those of Colonel Renard's airship, the " France," built in 1884, and the " Ville de Paris " resembles the older airship in many particulars. In September, 1907, M. Deutsch offered the use of his airship to the French Government. The offer was accepted, but delivery was not to be made except in Fig. 3.—The French dirigible "La Republique." 137
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