This paper presents a theory for calculating unsteady aerodynamic forces of a T-tail, of which the horizontal stabilizer is oscillating sinusoidally in a sideslipping or yawing mode. It is shown that numerical results are in good agreement with existing experimental results. Secondly, the flutter characteristics of a simplified T-tail is analysed by the use of the aerodynamic forces thus obtained, and the dihedral effect of the horizontal stabilizer is shown to play an important role in the flutter characteristics.
Converging cylindrical detonations are produced using Perry-Kantrovitz-type apparatus. Equimolar oxyhydrogen and similar oxyacetylene mixtures are utilized both for test and igniting gases. Effects of many experimental parameters on the stability of converging cylindrical waves are examined. It is concluded that the effects of the corner, the partitioning diaphragm, the ingniting mixtures and the initial pressures and species of the test gas should be noted in obtaining stable and approximately cylindrical converging waves. Although the observed propagation velocity is not well reproduced, the acceleration of the converging wave is strongly recognized in approaching the center.
To bridge the gap between the theoretical and experimental buckling pressures of perfect spherical shells subjected to external pressure, extensive experiments have been carried out in the course of the authors' research to make the characteristics of the buckling of shells clear. In the present paper, the outline of experiments is described first and then the buckling pressure is discussed in detail. Specimens, prepared by paying special attentions to the fabrication of perfect shells and to the realization of the ideal clamped edge condition, have been loaded pneumatically. The applied pressure and the resulting distributions of deflection and strain in shells have been recorded continuously up to the critical pressure. The buckling pressures measured are close to the classical value, and some questions about the nonlinear analyses reported so far are presented. The deformation pattern and strain distribution up to and at the critical pressure will be reported in the proceeding papers.