This paper presents a theoretical consideration on the interference between the local separeted region and its outer flow. To simplify the analysis, a straight wing with an infinite span is assumed to have locally nonuniform distribution of transition points. Using the boundary layer theory and lifting-line theory, influence of such local disturbances on the boundary layer and its outer flow is investigated in detail. From this, three-dimensional characteristics of the local separation are deduced as follows. Once the local separation occurs, the thickness of separated region is increased by the effect of trailing vortices and the thickness of boundary layer near its region is decreased. The effect of three-dimensional boundary layer is opposite to that of trailing vortices. Moreover the separated region is localized by the influence of induced cross flow as well as trailing vortices.
Nonlinear oscillation described by an equation x+sinx+x(ε1+ε2cosx)=0 is considered. Hori's general perturbation theory for non-canonical systems is applied. The condition for the existence of limit cycles in terms of ε1 and ε2 and an analytical expression for the solution of the limit cycle are obtained up to the first order. The analytical solution is compared with numerical ones and satisfactory agreement between them is observed.
The change of flight condition leads to the variation of aircraft's parameters. It can also vary the order of numerator in the pulse transfer function of such an aircraft. This means, in the discrete-time case, the change of the time delay. It is difficult under these circumstances to maintain the performance of the aircraft with conventional control methods. In this paper we propose, as an alternative scheme, an adaptive flight control system which can be used for the aircraft with unknown time delay and parameters. The proposed scheme has a desirable feature; by introducing a polynomial identity based on the upper bound on time delay, the control system can be synthesized simply in spite of unknown time delay as in standard model reference adaptive control system. Simulation studies are carried out for small-size high-performance aircraft to substanciate the analytical work.
It is difficult to control Short Take-Off and Landing (STOL) flying boat safely and quickly because the drag increases during lower speed for sea approach and, hence, this will cause some critical accidents. Speaking in control theory, this phenomenon means the transient adverse response due to the change of its transmition zero from minus to plus. To overcome this problem, Automatic Throttle System (ATS) has implemented. But it is shown by Yamamoto that the sea approach using this method will require a lot of time and this is not desirable for the rescuing mission. In this paper we propose a design method of CCV (Control Configured Vehicle) flight control system of STOL flying boat which enables the safe approach and its time reduction in spite of the presence of some deterministic disturbances. Several computational examples show the usefulness of the proposed method.
Flight path is calculated for the 1971 mid-air collision at Shizukuishi. The calculation is based on the flight-data-recorder records taken from the Government accident report. The crash point thus obtained shows fairly large discrepancy to the wreckage distribution. This paper reports about the contradiction and a new interpretation is given to the flight after the collision.