When a transport plane flies between two airports, it flies usually at somewhat or considerably faster speed than that used to be refered as economic speed, which is the speed at which the plane can fly over that range with minimum fuel consumption and also the speed which corresponds to the maximum CL/CD of that airplane. The greatest reason why the cruising speed used in practice is faster than the economical speed, is that the transport airplane is prefered to fly at the condition which corresponds to the maximum carrying capacity of that plane. (Carrying capacity F=Wp×Vc, where Wp is payload and Vc is cruising speed.) In this paper, from the above-mentioned viewpoint, under the conditions of a given take-off weight and a given block flying distance, the ratio of the difference dV between practical speed Vp and economic speed Ve, to Ve is derived as a function of the terms take-off weight W1, landing weight W2, openating weight empty Wemp and payload Wp, where, dV is assumed small, and Vp is the speed which corresponds to the maximum carrying capacity for the plane. And the results from applying this relation to many practical examples are compared with practical data.
For transforming the interior of the amplifier on the upper part of the other plane, by theorem of SCHWARZ and CHRISTOFFEL, it is generally difficult to get the transformation, when the amplifier has the off-set and the splitter. When the side wall angle is 45° or 30°, the transformation is able to be expressed as the formula, which includes the elliptic integral of the first and the third kind. In this analysis, by theorem of SCHWARZ and CHRISTOFFEL, the interior of the amplifier is mapped on to the upper part of the other plane, and the analysis is performed for the internal flow by the ideal fluid. The stream lines is obtained on the mapped plane from the complex potentials, and by the transformation of this stream lines, the stream Iines in the amplifier is got. In this analysis, the clock-wise vortex is placed to get the reattachment phenomenon.
An approximate analysis is presented of a twodimensional steady curved half-jet of an incompressible fluid. Employing orthogonal curvilinear coordinates which consist of the zero-streamline of irrotational curved flow to which the mixing layer is matched and its normals, the boundary layer equations accurate up to the second order are treated by the use of the small perturbation method. Expressing the small parameter as the power function of the streamwise coordinate x, where the parameter is the ratio of the width of the mixing layer to the local radius of curvature of the x-axis, both similar and non-similar flow fields are treated by changing the value of the exponent. The boundary conditions are imposed in the exact form on the first order solution but are given approximately to the second order one. The numerical results are shown graphically for two cases: the similar flow and the flow along a circular arc.
A test model having a backside long cylindrical space excluded by a rigid pipe was acoustically excited in an exponential horn. The analysis of the sound field both inside and outside the cylindrical pipe has been performed considering the correlation between the vibration of the panel and the sound pressure. Good agreements have been obtained between the analytical and experimental results of the rootmean-square and auto-correlation of the strain response. This result shows that the analysis of the sound field affected by the panel vibration plays an important role to get the good agreement. The influence of the panel vibration on a measured pressure, the relation between a measured and the exciting pressure, and the suitable position of microphone have been disclosed. In the present test apparatus, air vibration in the backside cylinder caused by the panel vibration has increased the equivalent damping coefficient of the panel. The value is about four times greater than that of the panel material itself.
This paper treats the problem how an airplane is controlled when its flight path is given. As this inverse problem is in the area (such as "pilotting technique") where there is "the gap between the theory and the practice, " its theoretical studies are very few. The controls of an airplane fundamentally consist of three control surfaces; elevator, rudder and aileron. And it can be interpreted that these three surfaces control the angle of attack α, the angle of sideslip β and the angle of bank φ respectively. We studied the dynamic and geometric meanings of these angles in the previous paper.1) In this paper the inverse problem of airplane general motion is developed by taking this triple (α, β, φ) as main parameters. First we derive the basic algorithm which is an approximate one but very easy to see through. And then, following this algorithm, the controls of an interesting flight example are obtained. Lastly the exact solution is computed by means of the iteration method and the solution of the basic algorithm.
On the basis of the fact that the value of viscosity of hydrogen is half as large as that of air, the new hydrogen analyzer to detect the difference in viscosity is proposed in this report. A special merit of this analyzer is to be able to use for combustible hydrogen-air mixtures because it acts by no means an ignition source. Experiments were made to determine the effects of the flow rate of the sampling gas, the concentration of hydrogen and the dimensions of the viscometer on the sensitivity of the analyzer. It was found that the sensitivity increased as the flow rate of sampling gas and the concentration of hydrogen increased. The sensitivity of the analyzer built as a trial was from 0.0926 to 0.862mmAq/% in the range of 20-80% hydrogen concentration at 10cm3/s of sampling gas. The results show the new analyzer is suitable for industrial use, for example to control the mixture ratio of hydrogen and air in the intake manifold of the hydrogen fueled reciprocating engines.