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50 A I R C R A F T E N G I N E E R I N G February, 1942 result of changes in the surface layers, there still to boss in the fourth or fifth power with its length. JAPAN remains the question whether or not the same I n the boss they are equalized, because the section TH E AERONAUTICAL RESEARCH changes take place inside of th e specimens. ther e is a circle. I n order to answer this question, specimens were INSTITUTE : TOKYO IMPERIAL Th e theoretical solution of airscrew blade bending subjected to prolonged annealing at a constant vibration of such changes as in Jh and Jfl, with its UNIVERSITY temperature , when the splitting phenomenon of the length, is not easy ; and by considering the root of (Kogyu Tosho Kabushiki Kaisha, Tokyo) α-crystals was observed also in their interiors, the th e blade, it will be seen that they differ greatly conclusion being that the diffused X-ray pattern of from the characteristic airscrew blade section form, Report No . 207, April, 1941. On the Nature α-lattice observed inside of the. specimen s is owing so tha t it may be regarded as par t of the airscrew t o a splitting phenomenon of the α-crystal. From boss. It may then be assumed that the airscrew of a Satellite in the X-ray Pattern of α-Crystals, thi s it is clear that the diffused X-ray pattern ob boss forms 29 per cent of the root of the airscrew and the Differentiation of a new Phase α' by the served within the specimens is not due to the pre blade, tha t it is rigid, and that the elastic airscrew Surface-Recrystallization Method in Certain liminary stage of precipitation of the γ-phase as blade forms the remaining 71 per cent; and, supposed by previous investigators. The writer's Ternary Alloys. Part I. The Iron-Nickel- further, that in these parts , th e areas of th e sections previous conclusions based on results by the an d their moments of inertia Jh and Jfl are in linear Aluminium System. By Syûiti Kiuti. (In surface-recrystallization method have been directly relation to the length of the blade. English.) an d conclusively verified by this X-ray analysis. Wit h these assumptions, namely, that the I t has been reported in previous papers that sectional area and moments of inertia of the blade X-ra y studies of th e magnetic iron-nickel-aluminium ar c in linear relation with its length, the authors Report No. 210, May, 1941. Resistance ternar y system resulted in the discovery of a new examined this problem theoretically and numerical Welding Light Alloys. By The Resistance phase α', as well as a complete change both in the calculations were made with actual datum of an ternar y equilibrium diagram and in the explanation Welding Research Committee of the A.R.I. 800 h.p . V type engine and its airscrew. of th e cause of th e high coercivity in this system. I n the reports of J. Meyer and B. C. Carter, the (In Japanese.) Owing, however, to the difficulties in the differ area of the blade is assumed homogeneous, the Th e application of the electric resistance welding entiation of the α- and the α'-phases, the discovery airscrew boss neglected, and the blade assumed to of light metals and alloys to aircraft manufacturing of th e α'-phase was accompanied by many difficulties extend up to the airscrew shaft. The authors is believed to contribute to the improvement of the in the early stages, the accounts of which were calculated also the case in which the blade is as qualit y of the aircraft, the increase of its production abbreviated in previous papers. But owing to the sumed to be homogeneous in section, and the speed and the lowering of its production cost. In historical importance of this discovery in physical airscrew boss taken into account, using the actual general, however, the properties of light metal, metallography as well as in the permanent magnet datu m just mentioned. especially its high electric and thermal conductivi industry , the writer gives here the early experi Th e results of these two cases, namely tha t of the ties, give rise to difficulties in resistance welding, mental data in connexion with the new phase α' homogeneous section and that of linear relation to an d in order to perform such welding, we mus t make introduced into this magnetic ternary alloy system. its length, arc compared. a heavy current flow through the contact point for Th e report consists of the following chapters. a very short time, namely a fraction of a second. Report No. 208, May, 1941. The Charac 1. Introduction. B y the progress of electric engineering, the teristics of the Aerofoil with Discontinuities 2. Differential equations that apply generally to possibility of welding of this kind was recognized problems of coupling the blade bending vibra along the Span, with Special Reference to the a few years ago, since when it has been promptly tion with the crankshaft twisting vibration. developed, and at present it is already being put on Effects of Cut-Out. By Tetusi Okamoto. (1) Differential equations, assuming the air production work in many aircraft factories. But if (In English.) screw blade to be rigid, for the case of a we observe the actual welding mechanism, we find V typ e 12 cylinde r engine. Th e present paper deals theoretically with an tha t there are many variables which have influence (2) Numerical calculation of the natural fre aerofoil with discontinuities along the span, such on the welding results. They are as follows : quency of twisting vibration of the crank as an aerofoil with rectangular cut-out, flap or (1) magnitude of welding current, shaft of a V typ e 12 cylinder engine, with aileron. It consists of three parts. In the first (2) time of current flow, actual datum. par t the approximate method of calculating the lift (3) mechanical pressure between electrodes, (3) General differential equation in connexion distribution of the aerofoil with discontinuities is (4) material of electrodes, with problems of the coupling of blade obtained, and it is shown that the present method (5) shape of electrode tips, bendin g vibration with the crankshaft ma y conveniently be used in practice with satis (6) material of th e metal sheets t o be welded, twisting vibration of a V type 12 cylinder factory accuracy. In the second part the charact (7) thickness of th e sheets, engine. eristics of the aerofoil with longitudinal slots are (8) surface conditions of the sheets. 3. Solutions of th e differential equations when the studied, and as special cases the divided aerofoil I t is no t easy to determin e these variables exactly, are a and the moment of inertia of the area of an d the aerofoil with cut-out are solved. The cal or to keep them constant and, moreover, we can get th e airscrew blade arc in linear relation to its culated results agree satisfactorily with the meas good welds only when a proper combination of the length . ured results. In the third part the characteristics variables is prepared. 4. Solutions of th e differential equations when the of the aerofoil with rectangular cut-out arc calcu Th e investigation of the resistance welding of lated, showing that the calculated results agree are a of the airscrew blade is homogeneous in light metal requires wide knowledge extending over satisfactorily with the experimental results. section. man y engineering departments, and, to make the 5. Numerical calculation of the natural frequen welding mechanism clear, various kinds of experi cies and their amplitudes of bending an d twist Report No. 209, April, 1941. An X-Ray ment s must be done. ing of the case of chapter 4 from actual datum. A full bibliography is appended. Study on the Mechanism of the Splitting 6. Numerical calculation of the natural frequen Phenomenon of α-Crystals in the Interiors of cies and their amplitudes of bending and twist Report No. 212, August, 1941. The Coup some Ternary Alloys. Part I. The Iron- ing of the case of chapter 3 from actual datum. ling of the Airscrew Blade Bending Vibration 7. Conclusion. Nickel-Aluminium System. By Syûiti Kiuti. 8. Appendix. with the Crankshaft Twisting Vibration of a (In English.) I n this investigation were obtained the first five V type Engine. By K. Tanaka and T. Th e writer has reported in previous papers that natura l frequencies in the coupling of the airscrew Ohino. (In Japanese.) annealed specimens of the iron-nickel-aluminium blad e bending vibration with the crankshaf t twisting magnetic alloys show diffused X-ray interference vibratio n for both cases ; namely, when the blade Th e natural frequency of a crankshaft twisting lines belonging to the body-centred cubic lattice, section is homogeneous and when the section and its vibratio n is usually calculated by assuming the while the separation of the (022) Co Kα or the moment s of inertia are in linear relation to its length. attache d airscrew to be a rigid body. The airscrew (022) Fe Kα doublet cannot be observed. The Two of them arc due to the crankshaft twisting however, instead of being rigid, is elastic, the diffused phenomenon of the X-ray interference lines vibratio n of one node and of two nodes, these values vibratio n of the blades being due to their bending was supposed by X-ray investigators heretofore to being equal t o th e case in which the y were calculated an d twisting. The problem of coupling th e airscrew b e due to the preliminary stage of precipitation b y assuming th e airscrew to be a rigid body. These blade bending vibration with the crankshaft twist of the γ-phase; which view, however, is beset with values moreover do not differ with respect to the ing vibration was recently treated theoretically by difficulties, both experimental and theoretical. abov e two cases. J . Meyer in Germany and B. C. Carter in England. Th e writer was of th e opinion, however, that the The y treated the problem by assuming the blade Th e remainder are due to the airscrew blade diffused X-ray pattern as revealed in annealed to be homogeneous in section and ascertained their bending vibration, that is, due to one node and two specimens of this alloy system is due to the pre results by model experiments. Further J. Meyer node vibrations in yfl direction and one node liminary stage of the separation of the new phase treate d briefly the problem in general assuming the vibration in yh direction. The frequencies for the α' from the matrix of the α-solid solution, and area of the blade and its moments of inertia in case of homogeneous section arc lower than those succeeded in obtaining an X-ray pattern of the potentia l relation with th e length of th e blade. of the case of linear relation to its length, their α'-phase in which it was perfectly separated from ratios being approximately 1·4 (2·0 in only one An example of the areas and their moments of tha t of the α-phase by the surface-recrystallization case). These ratios arc reasonable, if the airscrew inertia of sections of a three-blade duralumin method. In other words, from the fact that by the blade bending vibration only is calculated, assuming adjustabl e pitch airscrew are shown in Fig. 1. The surface-recrystallization method, the splitting phe th e root to be rigidly clamped. areas of sections of the blade are approximately in nomenon of α-crystals is observed in the surface linear relation to its length, but the moments of Fro m these results, it was found that in an actual layer of the specimens, it is concluded that the inertia of areas Jh and Jfl, the former being with case, with these couplings of the airscrew with the diffused X-ray pattern observed in the interiors of respect to th e minor axis an d th e latter to the major crankshaft, there are natural frequencies not only specimens is due also to the splitting phenomenon axis, are not linearly related. The moment of du e to the crankshaft twisting vibration, but also of α-crystals. t o the airscrew bending vibration, the former being inerti a Jh is approximately in linear relation to the th e same as that in which the airscrew blade is But , since the separation of the new phase α ' by initial part, and after reaching maximum gradually assumed to be a rigid body. th e surface-recrystallization method is merely the decreases, whereas the latter Jfl increases from tip
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Feb 1, 1942
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