To clarify the whole behavior of turning errors of the magnetic compass, many turns are conducted from various courses by the trainers of Civil Aviation College. In turning to the right, the maximal lag error of the compass occurs between the heading of 10° and 40°, and the maximal lead error occurs between the heading of 130° and 160°. The extent of the maximal error depends upon the angle of aircraft bank. An angle of bank has the greatest effect on compass errors among the flight characteristics of an aircraft. The effect of flying speed, the time rate of bank and flying altitude are investigated. The results of flight experiments quite agree with those of computing errors through Lindemann's procedure. As a result of the studies, turning error curve is proposed. The computed turning error curves to one angle of bank are almost the same for the compasses used today. This curve can be applied to any turning by using the magnetic compass.

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This paper presents an experimental study of shock wave/turbulent boundary layer interaction induced by a swept leading edge fin placed normal to the side wall of the wind tunnel. The experiments were carried out in a 8×10cmcm₂ supersonic wind tunnel at free stream Mach number of 2.47. A total of 4 fin type models with 40° half angle wedge type leading edges were used. Sweep angle was varied from 0° to 30°. Surface static pressure measurements, oil flow studies and Schlieren photographs of the flow field were made. It was found that, the separation shock angle and the plateau pressure are insensitive to the sweep angle of fin's leading edge. But increasing the leading edge sweep decreases sharply both the extent of the influence region and the maximum pressure on the plate surface.

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A new numerical method is formulated which belongs in discrete ones rather than mode methods of unsteady subsonic lifting surfaces. This may be said a final form (revision and extension) of the DSM (Doublet Strip Method). After integrating spanwise first the kernel function across a narrow chordwise strip, there appear just similar singular terms as in the DLM-C for two-dimensional airfoils. Thus Mangler's principal value can be avoided. The following chordwise quadrature may be carried out efficiently as in the DLM-C developed by our laboratory in past. This new method is designated as BIS (Box-in-Strip) method. Authors' basic thought is stated concerning about the reason for being of efficient linearized lifting surface methods, especially at high reduced frequencies and high subsonic Mach numbers. It is often not wellunderstood in our country. It is noted that results obtained through lifting surface methods may have significant influences into some other numerical schemes, such as Surface Singularity Method.

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In this paper, a superposition distortion index K_A2 is introduced to indicate the relationship between the distortion intensity and the fan speed. The data to calculate the K_A2 was obtained by the distortion experiments using the two stages axial flow fan and distortion screens. A number of conventional distortion indecies such as K_ra2, DI, D_min, K_θ, K_D2, DC60 are presented to evaluate the each radial and circumferential distortion intensity. In previous paper, both radial and circumferential distortion indecies are expressed in one figure to evaluate the distortion intensity more accurately. This method, however, cannot tell the influence of the fan speed. The index K_A2 includes the radial distortion index Kra2 and the circumferential distortion index K_θ, the influence of fan speed. The influence of fan speed was obtained from the stall margine decrease of the fan characteristics curves.

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