Dependence of helicopter lifting system loading on temperature variations in composite material properties

The results of studying the influence of physical and mechanical properties of composite materials on balancing characteristics and loading of a helicopter under changes of climatic operational conditions are described.     

Application of oil dispersion to enhance the efficiency of aircraft GTE oil system operation

The data obtained in the course of experimental studies of a promising technique for the MS-8P engine oil cleaning by its dispersion are presented. It is obtained that as a result of dispersion, the sizes of solid particles in oil appearing in the process of wear of the triboengineering system elements in the aircraft GTE rotors do not exceed 3 μm making it possible to increase the engine oil service life and durability of rotor bearings.     

A spherical dome in the temperature field

An exact solution of the uncoupled three-dimensional thermoelasticity problem for a spherical dome (hangar) is constructed. Displacements and stresses in the structure are determined as two-fold series with respect to solid spherical harmonics and trigonometric functions.     

Application of neural networks for the design of flight control algorithms. II Adaptive tuning of neural network control law

In this paper, we consider different approaches for the neural network controller tuning in the flight control system. Two of the most common tuning approaches in the adaptive control theory are applied. The first one uses parameter identification technique and consists in solving a real-time regression problem for the control law. The second approach is based on the Lyapunov direct method, which utilizes a tracking error as an absolute measure of tuning performance. The neural network control law are designed for the three-axis flight control problem and tested on the full nonlinear model of a fighter aircraft. Closed loop simulation results are presented and two adaptation algorithms are compared in the case of abrupt change of aircraft dynamics.     

Material deformation curve approximation in strength and stability analysis

A deformation curve approximation method applicable for materials without yield line and characterized by simple realization and a possibility of explicit representation of the stress-strain dependence is presented. The simplest approximation variant makes it possible to find critical stresses for beams or plates in the closed form.     

Numerical simulation of a flow around airfoil using inviscid gas equations

A method for determining a field of inviscid gas equation application in finding the aerodynamic characteristics of bodies is proposed; as an example, use is made of airfoils for which extensive experimental data are available. The comparative analysis of physical and numerical simulation results showed a good verification of the method presented.     

Evaluation of the influence of a measurable parameter error on precision of determining αΣ and Tg* by regression models

We present the regression models for determining the total excess air ratio α_Σ and gas temperature T _g ^* upstream of the high-pressure turbine formed on the basis of the engine parameter values that are regularly measured. The sensitivity of the regression models presented to the sensor and instrumentation precision is studied. The errors of measuring and calculating α_Σ and T _g ^* in different altitude-speed engine operation conditions are shown.     

An efficient method for determining a distance at direction finding of target with partially-known parameters

An efficient method for determining the slant distance from a rectilinearly moving target by two bearing measurements is described using a priori information about the probable magnitude of velocity, acceleration, and others. Also given are the assessment of method effectiveness and an illustrative example.     

深凹露天矿通风风洞研制与模拟实验

本文扼要阐述了开展露天矿通风研究、尤其是进行实验室风洞物理模拟研究的必要性。对露天矿通风模拟风洞的研制作了简介,指出了本风洞所具有的特点。文中介绍了最近完成的二项风洞模拟实验:对大冶露天矿深部开采风流结构及其污染物扩散净化能力进行了模拟研究,发现该矿具有比较独特的三维风流结构;对大爆破后靠自然风力稀释烟尘蘑菇云团所需的停工通风时间,分别完成了以风速 U_0和炸药量 A 为单因素变量的两组试验,揭示了通风时间与地表风速 U_0、炸药量 A_0的本质联系,推导出了通风时间的计算式。