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Aviation History
1916
1916 - 0017.PDF
pleasure and a commercial vehicle, and the manufacturer who is far-seeing enough to realise the unlimited scope of aviation as a sport and recreation, as well as its commercial possibilities, will reap a handsome benefit from turning his attention to the development of the small, low-powered and low-priced aeroplanes. I have yet to come across the man who, once having tasted the exhilaration of flying, is not an aviation enthusiast for the rest of his life, and there cannot fail to be, after the war, a number of pilots who, although no longer in the air services for various reasons, will be keen on " keeping their hands in " as civilians. Out of these quite a fair proportion will be in a position to buy their own machine, provided it is not going to be prohibitively expensive, either in first cost or upkeep. To cater for the requirements of these ex-service aviators will form a good opening for manufacturers, a comparatively small one, it is true, but an opening nevertheless which may— and in my opinion will—form the beginning of a huge industry, in which the man who looks ahead would have an opportunity to establish himself with a comparatively modest outlay of capital. While this is all a thing of the future—the end of the war not being in sight yet, and its termination probably going to be, as a friend of mine put it, " a jolly slow job for the first seven years "—there is another sphere in which the small low-powered machine would prove very useful at the present time. For brevet tests and extra practice after obtaining " ticket," both at civilian and service schools, where frequently much higher-powered machines are employed, the small machine designed to be relatively fast would seem to meet the requirements. Incidentally if a number of such machines were in use, forming a stepping stone from the school aeroplanes to the high- powered service machines, the country might be saved a goodly amount of money in smashes. What then would be the requirements to be met in order to provide an aeroplane which, without being too expensive, would be fast enough to furnish some really useful experience ? To be of any practical use it would have to be capable of at least 60 to 65 miles per hour, carry a supply of fuel sufficient for about three hours' flight, and have a landing speed in the neighbourhood of 35 m.p.h. My contention is that such a machine is possible with an engine as low as 30 h.p., and it is the object of this article to find out whether or not I am right in my calculations. If first estimates be wrong, we must investigate again until we have settled to our own ® ® The Air Raid on Salonika. As was not altogether unexpected, the first warlike act of the Central Powers against Salonika took the form of an air raid, of which the following details were sent to the Daily Mail by their correspondent at Salonika :— " German aeroplanes have been reconnoitring during the last three days. This morning (December 30th) four Aviatiks and two Albatroses crossed the zone occupied by the Anglo-French forces and dropped several bombs. One fell near the Italian hospital, another about 100 yards from the Greek General Zimbracaki, who was inspecting the 13th Regiment, and four in the fields close to the Alatini brickworks near Prince Andrew, who was following cavalry manoeuvres. One bomb dropped close to two Greek squadrons under the command of Commandant Metaxas, killing a Greek shepherd and four sheep. Bombs also fell near the Villa Alatini, the former residence of the Sultan Abdul Hamid. " The fleet's batteries opened a violent fire on the Aviatiks, with out result. Then three French waterplanes and three aeroplanes pursued the Aviatiks, and they retired towards the frontier, but satisfaction the question of the practicability of a machine capable of doing from 65 m.p.h. to 35 m.p.h., carrying a pilot and three hours' fuel. If any reader disagrees with me on any point I shall be very pleased if he will communicate his views, raising any point that may seem to hiin doubtful, and the correspondence ensuing and criticism offered should help greatly to add instructive interest to the problem. One of the first considerations when designing a machine is the choice of a body of such form and con struction as to give a maximum of strength for a mini mum of weight and resistance. In the first respect probably, and in the last certainly, the circular section proves largely superior to one of rectangular section, and the best construction of a good streamlined body, which would give the best results from the point of view of resistance, would undoubtedly be the monocoque type. Since, however, this form of construction is rather heavy, and costly to build, and one of the raisons d'etre of our machine is low cost, we had better dis miss the idea of a monocoque body and attempt to find other means of obtaining a good stream line form, which is such an essential factor in the equation of economical flight. That this is so will be readily realised when it is remembered that for each pound saved in resistance the machine will carry an additional load of 8 lbs., assuming a gliding angle of 1 in 8. As it would be desirable to know beforehand what will be the resistance of the body, we will choose a form of which we have a good supply of model figures determined by experiments. In Lieut.-Col. O'Gorman's " Notes on the Resistance of Airship Shapes " (Report No. 43, page 52 et seq., Technical Report of the Advisory Committee for Aeronautics for the year 1911-12) is given the resistance of a number of airship models, from which we shall choose that of the dirigible B.F. 36, the model tested being approximately of the dimensions we require for the body of our machine. In the accompanying graph (from the N.P.L. Report) are shown the results of the tests on this model, which was 17 ft. 3 ins. long by 2 ft. 11 i ins max. diameter. The valve of K for this model in the equation RT = KV1'"8 is RT = total resist ance in lbs. = 0*00091 V1'98, from which the resistance at any speed is easily found. The next step is to find a method of constructing a body, of approximately this form, without resorting to the expensive monocoque type. This will be dealt with in our next issue. (To be continued.') ® » their escape was cut off by Allied machines whtch had ascended from the aviation ground on the advanced lines. Taken between two fires, the Aviatiks gave battle. For a long time the machine guns were heard in the air, and the wings of the aeroplanes were pierced by bullets. The Aviatiks managed to descend, some near Ghevgeli and others near Kavadar on an aerodrome formerly used by the Allies. A captive observation balloon is constantly in use." Following on the raid, General Sarrail, the French Commander-in-Chief, ordered the arrest of the German, Austrian, Bulgarian and Turkish Consuls and their Staffs, who were placed upon a French ship. A large number of enemy subjects suspected of espionage were also arrested. The Greek Government addressed a protest to the German Government because the German aeroplane passed over Greek territory, dropping a bomb which killed a shepherd. Following on a protest by the enemy powers to Greece against the arrest of their Consuls, a formal protest was lodged with the Entente Powers. <7
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