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内容記述 |
The bending moments of the flanges of the wing ribs, whose webs are lightened with holes, were obtained in the previous report taking them as Vierendeel frameworks. From the bending moments the deflections are calculated in this report, and it is shown that, the coincidence with observed ones is fairly good for both wooden and duralmin ribs. A typical deformation of the wing section profile under severe load is shown in Fig. 62, from which we can see that the aerodynamic properties of the wing section will suffer a change to a certain extent in case of, for instance, pulling out of a nose dive. The ribs made of so bad a wood, as would not be qualified by the specifications for aeroplane materials, are very inferior to the ordinary ribs; strength loss 23%, deflection increase 47%, and weight increase 13%. The duralmin ribs, Fig. 52, also of the same type, which are more suitable for mass production, are much superior to the wooden ones,-390% increase in strength and 35% decrease indeflection. |