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Aviation History
1913
1913 - 1260.PDF
(/JJGHT NOVEMBER 22, 1913. the pilot's »eat. Spring wheels were originally fitted, but they were found to retard the machine's speed somewhat whilst taxiing on the ground, and were consequently removed. "The propelling force is transmitted to the tractor-screw by a system of wooden pulleys and a leather belt. " The designer demonstrated the efficiency of this belt drive before the writer a few days ago, and it certainly looks very promising. The control of the machine is very similar to the one-time popular Antoinette monoplane, but two small levers are provided instead of hand wheels. Up to the time of writing, the machine has [not ?] been tried as a cycleplane but as a glider. With the tractor-screw removed it has been towed (by a cycle) with very favourable results. It lifted easily, and its stability was very good indeed. Owing to the weather conditions it was impossible to take snap-shots, but as further trials will be made both as a glider and as a cycleplane, the writer hopes to be able to obtain some of interest." Referring to the above experiments, one, like Oliver Twist, " longs for more." In other words, what thrust (static) can Mr. Shorter obtain with his 5 ft. propeller of 7 ft. 6 ins. pitch, how many r.p.m. can he obtain without undue fatigue, and how long can he keep it up? Also when the glider (alone, we presume) was towed by a cyclist, was a spring balance inserted in the towing line to measure the pull (or thrust) ? Also in experiments which have been made by other clubs with towed gliders (man loaded) have spring balances been used to ascertain the same ? If not, why not ? As it so happens, the writer made some experiments a short time ago with a pedal-driven aerial propeller. It was not his intention to have published anything relative to these experiments until they were completed. As, however, owing to press of other work, this is likely to be some time, and with a view to any use they may be towards assisting forward any other experimental work of a similar kind, I give the results so far as 1 have at present carried them. Some experiments with a pedal-driven aerial propeller. under the circumstances. The gearing (as per illustration) was then increased to 12 to I, and this was found to be about right. Without undue exertion, the writer (who is by no means muscular) was able to turn the cycle crank twice a second and thus drive the propeller 1,440 r.p.m. ; this was continued for ten minutes without any undue fatigue. The thrust at 1,440 r.p.m. was 14 lbs., which is interesting because this is about what Mr. Mayer obtains with his Photographs by Mr. L. G. Ryley. THE SHORTER MONOPLANE.—On the left the front view of the chassis and propeller drive. On the right the machine ready for transport, with wings clipped along the fuselage. I should say that these experiments were undertaken to see what could be done towards driving a craft of the catamaran hydroplane type along water when propelled by an aerial propeller worked by foot power like a bicycle. The proposed floats (which are nearly completed) are two in number, 8 It. in length and 8 ins. square vertical section ; flotational capacity about 200 lbs. each. Their weight is very light, about 12 lbs. each. A skeleton wooden framework was covered with jfo in. birch (supplied by Messrs. W. G. Evans and Sons); this was given two coats of Bragg-Smith varnish, and then covered with Jap silk and again given two coats of the same varnish. The tops—not yet completed—will be covered with well-varnished silk only. Before the construction ol the floats was commenced, some preliminary experiments were made with a view to obtaining some idea as to what thrust an ordinary pedal driven aerial propeller would give. A rough-and-ready arrangement, as per illustration, was knocked together, and this, originally built " as a cycleplane made for two," was afterwards altered to a single driven machine. The propeller used (kindly lent the writer by Messrs. J. Bonn and Co.) was 3 ft. in diameter and of 2 ft. 6 ins. pitch, and was at first geared up about 4 to I ; this was found, however, to be quite useless, no resistance practically speaking being experienced, one curious effect being that it was somewhat difficult to keep one's seat petrol motor, which gives, if I remember correctly, approximately * h.p. Now the propeller used by the writer was by no means a suitable one to obtain the best results owing to its small diameter, but I especially wished to try such a propeller at the commencement before deciding whether to continue the experiments or not. The results obtained, which were better than I had expected, decided me to pursue the matter further, but it will not be possible for me to do anything more to them for some four or five months. The propeller in my case is chain driven, ordinary bicycling fittings being used. Ball bearings, save in the case of the propeller, are used throughout. Two chains are shown in the illustration—the bevel gear wheels driving the propeller having the same number of teeth. But when again fitting up the apparatus, only one chain will be used and a 3 to I gear employed in the case of the bevel wheels. It has occurred to me that there might possibly be some advantage in having the propel'er " free wheel." The case is, how ever, not at all analogous to that of the bicycle, as we have here merely the small momentum of the propeller, whereas in the case of the bicyclist one has the forward momentum of both man and machine. The wheels fitted to the apparatus were ordinary small iron ones, and the planks unplaned ; nevertheless, all the young people shown in the photograph were able to propel the apparatus 286
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