Stresses in the box-beam subjected to the transverse load are analysed by dividing into stresses of engineering beam theory and of residual. The residual is called "deviation stress" in this paper.
The relation between the deviation forces at three adjacent rib stations is expressed by an equation in the similar form to the wellknown three moment equation.
A set of these deviation equations for a multibayed box is easily solved by the successive approximation. It is the feature that the first approximation for these equations is in good approximation to the final solution.
Hence in the light weight structure design, it is possible to estimate directly the optimum size of each component in satisfactory accuracy by considering the above first approsimation.
It is found that the engineering beam theory can be called the zero approximation.
Effect of the fixing end condition is treated also.

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A numerical analysis is presented for the problems of the transverse impact on elastic-viscoplastic beam. The analysis is based on the method of characteristics and formulated with finite difference schemes. The computation is concerned with semi-infinite beams, including the effects of rotatory inertia, shear deformation and rates of strain in the plastic range.

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Drag of external stores installed on a supersonic aircraft deteriorates the performance like maximum speed, acceleration, endurance. Droptanks, pods, wing pylons belong to such stores. The drag coefficients of these stores are essential to estimate the performances, however, comparably difficult to acquire in supersonic region. When supersonic wind tunnel is not available, the coefficients can be derived through flight tests.
The proposed method depends on a comparison of supersonic acceleration flights between the clean and the externally installed configurations. The test aircraft is flown successively in that different configurations.
For each acceleration, flying altitude, starting speed of 0.9 Mach and initial aircraft weight are kept equal. Also the maximum engine power setting of after-burner is kept same all through the accelerations. Each acceleration range from 0.9 to 2.0 Mach is divided commonly into a number of small speed class. At each class, flight Mach number, time and fuel quantity representing aircraft weight or mass are recorded by the pilot.
For each class, based on equation of motion of the aircraft, the drag of the stores is calculated from the difference of the products between the two configurations, the product being the aircraft mass multiplied by the acceleration rate. Then the drag coefficient is derived as usual and plotted for the supersonic range.
As an example, drag coefficient for a wing pylon was derived from flight tests as 0.04 to 0.02 for the supersonic range regarding to its side area, and compared with the coefficient from wave and friction drag theory. Due to unfavorable flight conditions and lack of experience, the dispersions of the derived coefficients from the theory were not small.
By improving measuring technique and choosing flight condition carefully, this method may bring more accurate drag data and may be suitable when the flight test is feasible with other missions.

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Concerning the switching mechanism in a wall attachment fluid amplifier with the splitter and the off set, the theoretical analysis has been performed in the followings:
(1) On the assumptions of (a) and (b), the flow characteristics in the fluidic amplifier has been analysed by the potential flow to obtain the reattaching stream line and the pressure distribution.
(a) replacing the side wall of the splitter with the finite number of the vortex of the same strength, placed in the same intervals
(b) placing a vortex in the vicinity of the side wall
(2) To analyse the switching that happens by the instant closing of the exit, the velocity of the propagation of the pressure rise must be get. For the equivalent passage of the amplifier of the circular cross section, the velocity of the propagatioa has been able to get, and this velocity is approximated to that of the real passage. Experimental values of the three kind of switching time has been checked with the theoretical values.

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