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Aviation History
1913
1913 - 0769.PDF
JULY 19, i9i> All the wooden spars were made of white spruce. The elastic coefficient for each spar is given in the table : it was measured by the deflection of each spar under a single central load. Spars No. I and 2 are the actual back and front spars of the Wright biplane, and are, of course, easy to construct. UmRSFAR AB'6fib BC'TOi" K--66 " (/ycRf) LOWER SPAR m" "-, 040 (l&tfa^t) "Flight" Copyright. Diagram of the bracing system of the warping portion of the Wright biplane, which was used as a basis for the test. " Flight" Copyright. Sections of the spars tested by Mr. Alec Ogilvle at Eastchurch. Spar No. 3 was difficult to construct because the glue on such a long length gets cold before the nails can be driven in. Spar No. 4 is of the Maurice Farman type. Its halves are joined up with a fillet of hard wood. It will be observed that, although expensive to make, it gave very satisfactory results under test. Spar No. 5 is easily made with a spindle machine, but when tested shows up as being rather weak laterally. Spar No. 6 is a mild steel tube measuring 1 "25 inches in outside diameter. Its section is 19 gauge ; it is solid drawn and unannealed. The breakages were particularly interesting, and the accompanying photographs show up the weaknesses of the spars very clearly. Spar No. I broke downwards as a beam in the inner bay. It was obviously at the point of fracture also at the hook joint. There was twice as much deflection in the inner as in the outer bay. Spar No. 2 broke in the inner bay as a beam. It also broke at the screw holes of the hook fitting. This was probably because the screw holes cut into too large a proportion of the fibres of the spar. Spar No. 3 showed weakness in the glued joint. It was also weak against torsion, and twisted at the inner hook fixing through an angle of approximately 30° just before fracture. The fine nails used weakened the side members, as is shown by the failure in com pression at each nail. Spar No. 4 is undoubtedly the best spar of the series. It failed as a beam in the inner bay. Spar No. 5 is too weak sideways, and the failure occurred in the inner bay by the lateral collapse of the spar as a strut. This was not altogether unexpected, as the low lateral moment of inertia for this spar is very noticeable. It was also apparent from the fracture that a larger radius in the channels would have been an improvement. Spar No. 6 failed as a beam in the inner bay. The objection to this spar is that it is rather heavy. ® ® AIRSMIP NEWS. A Nocturnal Trip by "LI." ON the 9th inst., the Zeppelin naval dirigible "LI "left her hangar at Johannisthal at 11 p. m., and, after cruising in the direction of Potsdam and Jueterbog, arrived back at her hangar at 6.2S the next morning. Three-Hour Trip by " Adjudant Rean." FOR the training of officers the Astra dirigible "Adjudant Rean " made a voyage of three hours over the neighbourhood of Verdun on the 9 th inst. Two New Italian Dirigibles. TESTS are now being carried out over Lake Bracciano with two new dirigibles belonging to the Italian Army. One vessel is characterised by a speed which is only just under 80 miles an hour, while the other is fitted with a special platform for accommodating quick-firing guns. Mishap with the Veeh Airship. ON its second trial, on the nth inst., the Veeh airship, which is now designated Vi, after following the Rhine from Dusseldorf, had to make a landing at Oberembt, owing to the fact that the steering-gear refused to act. Eventually the dirigible was dis mantled, and sent back to Dusseldorf for repairs. TABLE I.—Strength. tt> B r. mil. 11 W "<5 c 0 sect i ros s area . «q . i n U c 8 adin g . run . . L o ried . lbs./f t ~ L W 128 210 170 223 210 135 The units for columns EI1 and EI are " millions of pound square inches." TABLE II.—Defections. Inner Bay. Outer Bay. Maximum deflection in inches in each span at loadings in No. lbs. per ft. of 15-6 26-1 36-6 47-2 1 15-6 26-1 36-6 47-2 2- 19 2*19 I'SO 1-94 1-94 •157 62-3 104-0 6o-2 90-3 83-9 69-9 1 2 3 4 5 6 '30 •10 •16 •18 •13 • 10 C70) •21 •38 •32 •^4 •24 I -22 •34 •6l 'SO '35 •51 2-i8 •50 •72 •49 •90 •37 •16 •35 •30 (•18) (•30) •66 •29 (•53) •48 •30 'So •85 •41 •70 C65) '44 •67 •94 •5a •80 •57 •85 ® ® The bracketed deflections were interpolated. The Royal Flying Corps Parseval airship and the " Beta " on Farnborough Common together last week, after a cruise. 795
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