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Aviation History
1914
1914 - 0024.PDF
I/UGHT] exception of the leading edge and the negative tips must be without any angle of incidence whatever. On models of a very small aspect ratio I tried a cambered wing, but with no improvement in gliding angle, and the stability of the models was not nearly so good. The steering and elevation were performed by the wing tips. ' To turn to the left, for instance, the negative angle of the left tip was increased, the object being to bank the model, which then turns automatically. A very pretty feature in the gliding of the e models is their ability to perform perfect spirals. Even the smallest models of this type flew very satisfactorily out of doors as well as in. The larger models travel about 40 to 55 ft. when launched from the hand, with a duration of 5 sees. ; their gliding angle being about I in 5 -5. Their ability to cope with quite a sharp breeze was really remarkable in such light models. Their chief disadvantage was that if " banked " by a gust they, would turn in the direction of the bank before recovering, the consequence being tha't it was very difficult to get a straight glide into a wind. When gliding with the wind this tendency was less noticeable. Interested by the stability shown by this type of model, I started experimenting with some gliders founded on the Weiss or Etrich principle. The method of construction of these models was almost identical with that used in the Dunnes, with the exception of the different shaped wings. Their behaviour was almost identical so far as stability and management were concerned, but their gliding angle was better—t in 6-237 being the record for this light type. Considering that the span was only 6 to 8 ins. they may, I think, be considered as on the whole successful. The improved gliding angle may possibly be traced to the more efficient disposition of surface which can be obtained with this type. They are, perhaps, slightly inferior to the Dunnes in stability, but not to any marked extent.. I found vertical fins quite ineffective on both these types, which are, I believe, different applications of the same principle. They can, in fact, be flown in the same way, and the same phenomena traced to almost identical causes. By adding a little more weight, and the judicious cutting down of plane area, the speed of these models may be considerably increased, but generally at the expense of the gliding angle. I have often obtained very pretty effects by launching two or more of these models placed one above the other at the same time, care being taken to put the lightest model on top. I wanted, however, to obtain a type which could be used satis factorily for gliding from hills or good outdoor slopes. My models so far had been too light, and without sufficient directive sense. I therefore slightly increased the span, which necessitated the use of a light stiffener, and to increase the weight I added a body which at the same time would give a certain amount of directional sense to the model. The sealing wax weight was carried inside the body, which is as far as possible of streamline form ; a rudder and fin were added to counteract the effect of the projecting "noie" in front, and as a result I obtained glides of over 20 sees, duration in quite a fair breeze from my " aerodrome " in Richmond Park. In this type of glider I found the Weiss models superior to the Dunnes. When gliding into the wind the models keep remarkably straight, and I have had more than one instance of models gaining altitude by up current". At Harnham, near Salisbury, one glider rose to a height of over 30 ft., and after a glide of well over half a minute (I had not a stop watch, unfortunately), landed ten or more feet higher than the starting point. The models, being made only of paper, do not, of course, last very long, about a fortnight being their average life, but considering that the most elaborate take but a quarter of an hour to twenty minutes to construct, one cannot expect them to. I once obtained a glide of 51 ft. 3-5 ins. with one of these when launched from the hand on level ground against a very slight breeze, the average being about 45 ft. This is, of course, nothing wonderful, but is quite good enough to give very good glides off a fairly steep hill. The increased weight and speed of the heavy type far outweighs shortcomings in gilding angle when there is any wind af all. From my experiments as so far conducted, I have come to the following conclusions : (1) That single plane models of the Dunne or Weiss type are the most satisfactory. (2) That these models will not fly without a decided down turned leading edge. (3) That the main surface of the plane should have no angle of incidence. (4) That negative tips must not be too large in relation to the rest of the model. (5) That fast models are more satisfaclory than slow ones. (6) That the weight should be well forward. (7) That the e.g. must be low rather than high. (8) That the wing tips must be depended on for control more than fins or rudders. (9) That the models turn automatically if started with a bank, or so adjusted as to bank themselves. (10) That in models without a "body" no fins are needed, but when one is fitted a counteracting fin is needed. Generally speaking, a stiffener is required only in models of over 8 ins span. I may add that all the designs submitted can be cut from any suitable piece of notepaper. As a matter of fact, three of the smaller gliders may be cut from a single sheet. When stiffeners are used, they should be cut from wood spills and seccotined to the plane. JANUARY 3, 1914. In my more finished models I varnish the body, but it is not essen tial. I am proud to be able to say that I have interested more than one person in aviation by my small attempts. Mr. F- Handle? Page'^ Coming Lecture. Considerable interest, from an aeromodellist's point of view, is centred in the above lecture on " The Dependence of Aviation on Experimental Model Work," at Caxton Hall, Westminster, on January 9th, and the attendance will, we expect, be a very large one. The chief point of interest probably lies in the fact that the lecturer is so well known in connection with his practical as well as theoretical work relative to full-size machines. In consequence, the pronouncement of his opinions with respect to the value of model work as bearing upon full-size design will be I awaited with no little expectancy. ..-i-iSfe The Coming Exhibition at Qiympia. Aeromodellists who have any intention of exhibiting at the above, which will be held from March l6th to 25th next (both dates inclusive), should already be at work. Full particulars must be sent in by March 4th, to ensure insertion in the official catalogue, after which date no entries will be accepted. Everything sent by rail, &c, must be sent carriage paid. Members of the K. and M.A.A. pay a special fee of 2s. 6d. per model, other exhibitors 5^. Every exhibitor will be provided with a free pass to the Exhibition during the whole period. Exhibitors can either exhibit as com petitors or non-competitors, i.e., their models are for exhibition but not competition. Some little difficulty appears to have arisen with regard to the " loading" question (to which reference has already been made in this section), and the writer has been asked to explain it. Judging from the leaflets sent out to intending exhibitors, there does not appear to be anything in the nature of an explanation really required—save in one point only. A minimum loading of 4 ozs. per sq. ft. in the case of monoplanes, and of 3 ozs. per sq. ft. in the case of biplanes, means that if your model weighs complete, say, 12 ozs., then, if a monoplane, it must not have aggregate sustaining surfaces greater than 3 sq. ft., or if a biplane of more than 4 sq. ft. This applies to classes 2, 3, and 5, but not apparently to 6— weight-carrying models, since no mention is made of the same. There is, I suppose, the difficulty of the non-lifting tail area, although I have not personally heard this mentioned. With respect to this I cannot at present make any statement, save that I should certainly vote for it being reckoned as part of the sustaining surface, since at times, at any rate, it undoubtedly acts as such. A "Record" Quick Rising Model. '* The following may be interesting to readers of the Model sec tion of FLIGHT," writes Mr. Clifford W. Tinson (Bristol): "A friend and I recently decided to try and build a model, which would get off the ground in less than a metre, there being no restrictions as to size, &c. I have been successful in doing this, the shortest run being 2 ft. 6 ins,, or considerably less than two and a half times the length of the model, which is 14 ins. over all. So far as I know this is a record, though I think it is quite possible, with a little care, to reduce this to half that figure. The flights were all indoor ones, so there is no question of wind." ® ® ® ® KITE AND MODEL AEROPLANE ASSOCIATION. Official Notices. British Model Records. Single screw, hand-launched Duration D. Driver 8s sees. f Distance - R. Lucas 590 yards. •"t Duration ... G. Hayden ... 137 sees. Twin screw, do. c- . tc A \ Distance ... W. E. Evans ... 200 yards Single screw,nse off ground < - Twin screw, do. W. E. Evans L. H. Slatter 64 sees. 365 yards. 2 mins. 40 sees. 266 yards. 91 sees. 190 yards. 94 sees. 35 sees. 29 sees. 60 sees. J Duration J Distance '"1. Duration ... J. E. Louch Single-tractor screw, hand-/Distance ... C. C. Dutton launched ...IDuration ... J. E. Louch T! _<r' / Distance ... C. C. Dutton Do., off-ground "tDuration . J. E. Louch Single screw hydro., off-\Dlirat;on L. H. Slatter water -. ... ... j Single-tractor, do., do. ... Duration ... C. C. Dutton Twin screw, do., do. ... Duration ... L. H. Slatter Aero Exhibition.—Will all intending competitors send in their names to the hon. sec. at once, so that an idea of the space required can be estimated ? Also will all hon. secretaries who wish a stand reserved for their club write stating if possible size of stand required ? Sealed Handicap Competition.—This competition was held on Wimbledon Common on Saturday, 20th ult.. but did not attract a large entry. The result was:—1st, A. F. Houlberg, scratch; 2nd, F. W. Jannaway, 5 sees.: 3rd, L. D. C. Chown, 15 sees. ", 4th, H, Bond, 5 sees. The judges were Mr. L. Ingram and the hon. sec. Lecture and Discussion.—Will all affiliated clubs secretaries advise the hon. isec. of the number of seats they wish reserved for their members at the discussion on the 9th inst. ? Greetii g.—The president, Sir John C. Shelley, wishes the Association and the members a prosperous New Year, and he also hopes that ail will do their utmost to increase the membership and so strengthen its hands. 27, Victory Road, Wimbledon. W. H. AKEHURST, Hon. Sec. 24
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