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Aviation History
1916
1916 - 0037.PDF
JANUARY 13, 1916. the formers at very short intervals. Everything considered, it would appear that it would be better to sacrifice any reduction in resistance that might accrue from adding more sides to the polygon, since with eight longerons a reasonably good shape is obtained, while the various bays of the girder can be made of fairly standard proportions. We could, by adding a stringer between every two longerons, obtain a slight reduction in head resistance, but it is questionable whether the gain thus obtained would be sufficient to be worth the extra trouble and expense. If, then, we decide on a body with eight longerons, the next step is to design a suitable support for these. Three-ply formers have already been suggested, and a simple form of these, which could be quickly and cheaply made, is shown in the right-hand sketch. As the longerons will taper from the pilot's seat to the stern, I would suggest that it be best to buy the three-ply wood in squares of suitable size, and cut out the octagon and circle oneself. As for the method of securing the longerons to the formers, I suggest wiring plates similar to those shown in the sketches. These would be very cheap to make, and should be quite suitable for the purpose. As a matter of fact, it would probably be possible to dispense entirely with the use of wire-strainers, at any rate in the rear portion of the body, since the bolts passing through the wiring plates and formers could be made to perform the function of strainers, and a considerable saving— both in weight and cost—thereby effected. If the bolts were made sufficiently long and all the bracing wires in each bay were bent over two pegs so as to be of exactly the same length, the tightening up of the bolts should put the same amount of tension in each wire and a true shape be obtained. A little experimenting might be required before the exact length of wire was found, but once this had been accomplished the board with the pegs for all the wires would be kept and thereafter the exact length of the wire in any bay would be known. As a matter of fact this method is, I believe, employed on the Wright biplanes without any means for tightening up afterwards, so that it would seem that with the extra tension that can be put on the wires by means of the To be l/jjCHf] bolts, as suggested, it would be a very economical way of effecting the cross-bracing. Of course if objections were taken to the method, it would be a simple matter to incorporate strainers, as the bolts would then simply be used to hold down the wiring plates. ' HV. Before going any further with our design, we can decide pretty well on how to terminate the tail end of the body. To form an anchorage for the rear end of the eight longerons, I would suggest a tail-piece of the shape The tail piece which terminates the body. shown in the sketch. If made of spruce and hollowed out it should not be prohibitively heavy, and would be made to take the horizontal tubes for the elevator and the vertical rudder-posts. Having now decided on our general body design and on the details of the construc tion for the rear half, we can begin to draw out an out line of the body. The details of the front part will probably have to be somewhat modified when the wing attachment comes to be studied, but this problem will form the subject of the discussion in our next issue. continued?) ® ® ® ® I WAS chatting to a pilot the other day about flying in general and speed in particular. During the conversation he happened to remark that he had noticed a very distinct falling off in speed as the altitude increased, and wondered at the reason for this. It is quite well known to pilots that the speed does drop with height, and the cause, I believe, is generally supposed to be that a smaller charge is taken in by the engine, as evidenced by the fact that as the altitude increases the petrol has to be cut down to avoid too rich a mixture. If any reader can offer a more " scientific" explanation we shall be glad to give it hospitality in these columns for the benefit of others who may be less familiar with such side issues in connection with practical aviation, xxx A time recording clock has been installed at the Beatty school, and is a source of much amusement to the pupils who are not used to " checking in " and "checking out." In consequence a great deal more card punching than is strictly necessary is going on. And it is not only the pupils' cards that are punched, but anything that will go into the slot. I am told that it is quite a common thing for anybody wanting to " know the time " to go to the new recorder and get the time of day stamped on any 3/
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