Aerodynamical parameters in longitudinal model of a certain type of helicopter are identified in the paper 本文主要进行了某型直升机纵向模型的气动参数辨识研究。
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On the basis of analyzing the aerodynamical property and the construction of usual axial fan , the aerodynamical property and the construction of contra - rotating axial local fan are studied in the paper . moreover , author has designed a kind of contra - rotating local fan , which has the characters of low noise , high efficiency , well aerodynamical performance , optimum structure , and large power 本文在分析了普通轴流式通风机的气动力特征和结构的基础上，研究了对旋式轴流通风机的气动力特性和结构特点，设计并制造出了一种风量大，风压高，噪声低，效率高，气动性能好，体积小，结构新颖的2 30kw新型大功率对旋式轴流局部通风机样机。
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Then , the comprehensive optimum method to improve the comprehensive nature and reliability of contra - rotating axial local fan is put forward . and a set of computing software about aerodynamical parameters of contra - rotating axial local fan is designed , which can be used to design a new kind of contra - rotating axial local fan with higher efficiency 采用了综合优化分析方法后，大大提高了对旋式轴流通风机的综合性能和可靠性，作者所编制的计算机软件能自动完成气动力参数的设计计算，自动快速设计新型对旋式轴流通风机。
