GRNTI 45.01 Общие вопросы электротехники
GRNTI 55.42 Двигателестроение
GRNTI 55.45 Судостроение
GRNTI 73.34 Водный транспорт
GRNTI 44.31 Теплоэнергетика. Теплотехника
The known methods of calculation of stability of hovercrafts tend to be cumbersome and poorly accurate and due to this, their use for practical calculations is complicated. The proposed method of calculation of amphibious hovercraft with flexible ballonet enclosure assumes the use of the classical theory of stability, based on the Euler’s hypothesis about coextensive inclinations. The results are based on the known method of accounting for the effect of free surface of liquid on stability. It is shown that with the excess of width of constructive waterline over the width of the free surface in the cavity under the air bubble the metacentric radius will have a positive value. There was adopted a number of assumptions in the calculation scheme of the vessel: the ballonet with flexible enclosure have a circular shape, an air gap between the ballonet with flexible enclosure and the surface of the water after the air outflow is not considered. The plane elastic problem, where the length of the vessel in the longitudinal direction equals to 1, is analyzed. The calculation formulas are derived to define the initial metacentric radius. Though the direct analysis of the obtained dependences is very complex, the latter were converted into dimensionless form. On the basis of the carried out calculations, the graph of the dependence of the initial metacentric radius on the relative radius of the ballonets of the lower tier and the relative distance between the ballonets is designed. An example of using the results to estimate the initial stability of the real amphibious hovercraft with a flexible ballonet enclosure "Gulf" (developed and produced in JSC "N Sitek") is presented. The analysis demonstrated that the center of gravity of the vessel may occupy a high position, but structurally it is usually much lower, which contributes to the confrontation of the dynamic inclining moment.
amphibious vessel, ballonet, air bubble, flexible enclosure, initial stability, metacentric height, center of gravity
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8. URL: www.nsitek.ru (data obrascheniya: 10.07.2014).