Dissertation > Aviation, aerospace > Aviation > Various types of aircraft > Aircraft > Dedicated aircraft

Research on a Forest Fire-Fighting Aerial Bomb Release System of Pod Style Special Used for Helicopter

Author GuQingMing
Tutor LiuShaoGang
School Harbin Engineering University
Course Mechanical and Electronic Engineering
Keywords forest fire-fighting aerial bomb release system helicopter slung-load modalanalysis modal analysis
CLC V271.3
Type Master's thesis
Year 2012
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Forest fire is a kind of severe natural disasters. Crown fire is the most damaging forestfire in all types of forest fires, however, the current firefighting equipment cannot extinguishthe fire directly and effectively. In recent years, the method that using the forest fire-fightingaerial bomb to estinguish forest fire has been proposed by forest fire expert of our country.The purpose of this paper is to design a release system of pod-style, which is special used forhelicopter, for forest fire-fighting aerial bomb. The release system can load forest fire-fightingaerial bomb which is launched over the fire area by a helicopter to extinguish the forest crownfire. For the early and sudden forest fire, this system can respond fast and inhibit fire quickly,and the fire fighting policy of “fight it early, fight it small, and fight it out” can be achievedaccordingly.The aviation fire-fighting equipment status of domestic and abroad was introduced inthis paper, the design requirements of bomb release system was defined through analyzing itsworkflow. The release system was functional decomposed through the functional analysis andthe analytic hierarchy process, and the hierarchical structure of the release system wasestablished, the general scheme of mechanical system and control system were completed.Aiming at the specific functions achieved by sub-function units of the mechanical system,the solution to the sub-function unit was obtained step by step. The actuator of sub-functionunits was assembled and the static analysis of complex welded components was carried out bymeans of the finite element software ANSYS12.0. Considering that the mechanical system oftruss structure was easily produced the resonance phenomenon by the influence of wind loadand helicopter in the work process, the modal analysis of the basic module, first assemblymodule and the mechanical system loaded twelve or sixteen forest fire-fighting aerial bombswas carried out, and the corresponding natural frequency was obtained.The fire fighting process of forest fire-fighting bomb release system used for helicopteris complex, the dynamic equations of the release system when the helicopter flies and hoverswere gained by establishing the model of the release system, and the generalized forceequations of the helicopter suspension point were obtained. The helicopter working height ofreleasing forest fire-fighting aerial bombs was obtained according to the dispersion requirement of bomb hit point.Finally, the function achieved by the sub-function unit of control system was analyzed,the control circuit of the lower computer system was designed in detail, and the solution tofunction units of PC system and control software was described briefly.

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