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Aviation History
1912
1912 - 0667.PDF
Conducted by V. E. JOHNSON, M.A. Hydroplane Floats. MR. F. S. GORDON (Scottish Ae. S. Model Aero Club) writes, thanking us for the attention recently given to hydro-aeroplanes ; in his letter he says : " I can assure you the ordinary * flyer ' is—with a few exceptions—getting quite stale up here, and is only to be seen •A *&. Figs. 1 and 2.—Two types V.E.J, stepped floats. A B = water line about once a month. I have been following with interest your notes on floats, and have made a set of three of the section shown in FLIGHT (V.EJ. type). They appear to be very efficient. The Voisin type are fairly good as hydroplanes—the model rising very easily with them. I have discarded the torpedo or tubular type entirely." Mr. Gordon also sends the following calculations re size of floats required for a model of given weight—weight meaning the inclusive weight of everything. Let us suppose the weight of the complete model to be 16 ozs. Now, I cub. in. supports approx. "037 lbs. 1 x 1 • '• .QVJ = 27*02 cub. in. required, add J for safety factor and we have 33775. Assume the floats 3 in. chord by § in. deep at I in. from leading edge, 3x3x2 = 1 \ in. sectional area. 4 x 3 Now 33775 cub. in. -f- \\ = 22'5i6 in. for span of float— . •. 2 floats 7 ins. x 3 ins. x J in. 1 float 8 ins. x 3 ins. x f in. would suit, allowing for weight of floats at \ oz. each, and one- quarter safety margin on total weight of model. We shall be pleased to hear what any of our readers who are experimenting with floats have to say with reference to the fore going. Personally we should say a 8 to 10 oz. model—hardly a 16 oz. Stepped Floats. According to the Westminster Gazette of July 9th, stepped floats are the subject of letters patent granted to Mr. A. E. Knight (January loth, 1907), and users of the same are (very probably in all innocence) infringers thereof. The number of the patent is not given, but the date of application was August 2nd, 1906. Apart from the question of patents, which does not concern us, there is one very interesting point dealt with which was raised in the last issue of FLIGHT. The remarks are accompanied by three diagrams, the second of which shows the position of the hydroplane when at rest — the water line is shown—and the top of the tread of the steps (there is but one) is above the water line. Previous to seeing the Westminster Gazette I had tried some experiments on the air tube method referred to in last week's issue. The method consisted in hauling through the water — a solid wooden stepped float — con taining a smooth copper tube, in which was floated a little round wax pellet. It was found that on the hydroplane rising sufficiently to let in air from the sides the pellet was immediately swept out of the tube and left behind—but not so far as I could ascertain before that occurred. As a result of this experiment I designedithe stepped float shown in Fig. 1, which, it must be confessed reminds one somewhat of the gargoyles on Notre Dame—the tread of the steps is, it will be noticed, very deep compared with the depth of the float. Finally, the animal, i.e., the float was decapitated and given the section shown in Fig. 2, which, it will be noted, has a somewhat strongly-marked inverse curve, this type being found the most efficient of many that I have tried. Whether for a model in which duration of flight has to be obtained in conjunction with a quick rise from the surface of the water it is superior to the type given in FLIGHT of July 6th I am not yet prepared to say. To those who have not yet taken up model hydro-aeroplaning we can certainly recommend it as the most fascinating, not to say exciting, branch of model aeroplaning as yet developed, combining as it does all the delights and excitement of a water sport with the ordinary joys of model flying. Model Flying ln Australia. We have received the following account from Mr. H. P. Wood, of Mount Albert, Melbourne, concerning some recent flights made by him :— " Since writing you last I have had an extraordinary flight with one of my models, which I think will be of more than usual interest. It occurred on the morning of May 5th, the weather being beautifully fine and warm, with an almost imperceptible following wind. After launching the machine in the usual manner it flew a considerable distance (somewhere about 600 yards, I should say); the power then ran out, and instead of starting to glide down as usual, it began to ascend in large sweeping circles, until it was only with the aid of a pair of field-glasses that it could be kept in sight. Eventually it landed 1,560 yards from the starting-point, and was in the air for 9 mins. The time was carefully taken, and the distance measured in a straight line from start to finish. I think it clearly shows that my machine got into an ascending air current, as it showed not the slightest inclination to come down when the propeller stopped revolving. As this flight might seem almost incredible, I have obtained the signatures of those who witnessed it. The machine itself is my own design and construction entirely, the only portion not manufactured by myself being the rubber. It is the thirty-third Mr. H V. Wood and his model. • - 1 model I have built in the last three years. Principal dimensions:— " Length of fuselage (triangular) = 4 ft. ; span of main plane = 4 ft. ; chord of main plane = 7 ins. ; span of elevating plane = 1 ft. 8 ins. ; chord of elevating plane = 4 ins. ; diagram of each propeller = II ins. ; pitch of each propeller = 19 ins. " Each propeller is driven by 8 strands of J-in. strip rubber (Warburton, Allen and Co.'s, of Leicester). Weight of complete machine = 9 ozs. " The following isa table of my longest flights with thismachine :— 6 Date, 1912. 0 > 0 B$ 6 0. • •si n a u a « > ~ *-> 0 QJ a .S u ttj <n Remarks. Feb. 18th Mar. 2nd Mar. 24th Mar. 31st April 13th April 14th May 5th May 12th May 12th 750 810 820 1,000 820 820 1,000 940 940 ft. 1,410 2,160 2,000 1.779 i,875 i,35o 4,680 i,788 2,688 sees. 62 55 83 118 * 67 540 148 230 No time taken. Straight flight. Gusty wind Straight flight. Strong wind Dead straight. Calm Circular flight. Calm Dead straight. Calm Semicircular flight. Strong wind Circular flight. Almost calm Circular flight. Calm Straight. Dead calm 667
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