Speed Plane Research Articles

Some Aspects of Aerial Combat

A dogfight between two aircraft each represented by a point mass in a horizontal plane of constant speed with bounded turning capability is examined. A number of complexities associated with this problem are avoided by the way the capture zones for each of the players are defined. However, by so doing, the possible outcomes of mutual destruction and draw are not distinguishable from a win by each of the players. Both the methods of Qualitative Game Theory and Control Theory are used in the analysis of a particular example. Two regions of state space of interest to the first aircraft are delineated. These regions have the property that if the second aircraft is located in the first region, the first aircraft can win the dogfight; however, if the second aircraft is located in the second region, then the first aircraft may lose the dogfight.

On Motions of a High Speed Planning Boat in Regular Head Sea

Recent advances in the research of ship motion in a seaway have enabled to predict the ship motion. These researches, however, are restricted to those of displacement type ships such as a merchant ship and a destroyer, and as to behaviours of high speed planing boat in a seaway few available researches have been published.In the present study the towing tank test of a torpedo boat model was carried out in regular head wave and experimental data were discussed along with the results calculated by Ordinary Linear Strip Method (O. S. M.).The conclusions deduced from these studies are as follows, 1) High frequency components appear in pitching and heaving oscillations at higher encounter frequency, that is, at higher speed and shorter wave. In these regions, each mean value of the pitching and heaving oscillation becomes larger compared with the trim angle and vertical displacement in still water.2) The motions calculated by the O. S. M. give good agreement with experimental data for Fn< 0.5, but they do not always for higher Froude number.3) In spite of much higher frequency components in the motions, the amplitudes of pitching and heaving motions are almost proportional to those of the wave, that is, the linearity to wave height is nearly conserved.

Low speed MHD Couette flow of a slightly rarefied and electrically conducting gas

The effects of an applied magnetic field on the steady, laminar, low speed plane Couette flow of a slightly rarefied and electrically conducting gas are studied. Consideration is given to the slip-flow regime, wherein the gas rarefaction begins to play its important role. The generally accepted method of analysis for slip flows is utilized, i.e. the continuum magnetohydrodynamic equations of motion are used throughout the gas, together with the first and the second order slip velocity and temperature jump boundary conditions. Considerations are further given to (1) the case of zero electric field and (2) the case of a nonconducting channel in which the net current across the channel is zero.

Effect of tunnel on the resistance of high-speed planing craft

Tunnels are provided in ship hulls to accommodate propellers under reduced draught conditions, thereby avoiding reduction of propeller diameter and consequent loss of efficiency. In this work the hydrodynamic effect of propeller tunnels in high speed craft, by way of modified resistance and pressure distribution, are studied both numerically using CFD, and experimentally using geometrically scaled models. The experimental study has been conducted on the model of a single hard chine hull form designed for specific length to displacement ratio. The parametric study considers two other draught conditions. In order to bring out pressure influences, CFD based simulations have been carried out. It is noted that the pressure distributions are altered around the tunnel region and, for an investigated case of tunnel area ratio, there is consistent reduction of resistance for all the three draught conditions tested. The study also compares the merits of the modified Froude extrapolation method, after correction for flow velocity due to pressure development in the hull zone, with the classical Savitsky's method for planing hulls. The qualitative aspects with respect to pressure distribution are brought out in the CFD based studies and the pressure predictions do show consistency with obtained experimental data. Keywords: High speed planing craft, Tunnels, Resistance, Extrapolation methods, Pressure distribution, CFD Studies. doi: 10.3329/jname.v2i1.2025 Journal of Naval Architecture and Marine Engineering 2(1)(2005) 1-14

High Speed Plane Bending Fatigue Test : 4th Report, Theoretical Consideration on the Speed Dependency, Part 2

High Speed Plane Bending Fatigue Test : 4th Report, Theoretical Consideration on the Speed Dependency, Part 2

Nonparallel Light, Plane Grating Monochromator

A high speed plane grating monochromatic illuminator intended for the vacuum ultraviolet and using nonparallel light is described. The light undergoes only two reflections between entrance slit and exit slit. Entrance slit and exit slit are on the principal axis of an ellipsoidal mirror, thereby eliminating astigmatism and spherical aberration.

High Speed Plane Bending Fatigue Test : (2nd Report, On the Speed Dependency of the Endurance Limit)

In order to investigate the effect of stress reversal speed (or frequency) on the endurance limit, the specimen of carbon steel and nickel-chrome steel were tested with the High Speed Pneumatic Fatigue Testing Machine developed by the author. The test results have shown that the endurance limit has a tendency to increase with frequency in the high frequency range, while it is independent of frequency in the low frequency range. The boundary frequency seemes to become higher according as the internal friction of the material decreases. These phenomena could be explaind rheologically with the visco-elastic model.