| Popis: |
T E use of models to predict the full-scale behavior of a structure is gaining increasing favor in the field of aeronautics. This t rend to model investigation is due not only to the saving in expense, labor, and time involved, bu t also to a better understanding of model laws and to recent improvements in the ar t of properly representing the prototype structure. Some time ago a practical type of model girder was developed, which permitted the axial, bending, and torsional elastic characteristics to be varied independently, and, further, it incorporated a convenient and sensitive means for measuring the corresponding strains and stresses. As a par t of an investigation program of the Special Committee on Airships a complete airship model, using this type of model member in place of the corresponding prototype girder, was constructed and tested. The work was carried ou t with the financial assistance of the Navy Department. The test program was carefully chosen so t ha t the effects of local loads could be conveniently isolated from the effects of general loads and in this way much of the confusion tha t has occurred in many previous model and full-scale tests was eliminated. M a n y variations of the structure were investigated such as with and without side or bot tom gangway and with high and low initial tension in the shear wiring. Fig. 1 shows a par t of the complete model rigged for test, with radial loads being applied to springs between the model and external loading rings. |
