Vol 61, No 2 (2018)

Based on a flight experiment, the difference between the total aircraft noise level and the ambient noise is proposed to be used as an audibility criterion for unmanned aerial vehicles equipped with piston engines. It is found that the unmanned aerial vehicle becomes audible for an observer at a criterion value of 3 dBA.

The equations of the mathematical model are solved in terms of special functions. The results for the design scheme of the aircraft forebody are obtained with a guaranteed accuracy by the stable method of functional normalization.

The problem of strength and stability of shells under torsion and internal pressure was solved. It was found out the influence of the internal pressure, ellipticity and nonlinearity of deformation on the critical buckling load of the shell.

The influence of initial deviations from the ideal circular shape on the dynamic characteristics of the thin circular cylindrical shell is investigated. The emergence of new zones of splitting the flexural frequency spectrum of imperfect shells is detected.

In this work, we investigate an application of symmetrical deflection of the split elevators and rudder up to 45 degrees to function as air-brakes during landing run for shortening its distance. A computational analysis for the landing run under standard atmospheric conditions is conducted. The effect of the proposed solution on the aircraft structure and performance was studied.

The problem of stabilizing the spacecraft orbit attitude was solved analytically for the sixth order model of its rotary motion with the use of the output feedback control synthesis that is based on decomposition of a control object. Numerical simulation data are presented.

In this paper, the algorithm of automatic landing flare is designed based on the maximum coordination between the trajectories, which are convenient for the pilot to operate in manual mode and the one attained by the auto-landing system according to the algorithm of optimal flight control.

Two-phase jets with step change in initial fields of phase parameters are analyzed. The results of calculating these jets make it possible to formulate recommendations on control of the range for such jets.

The new conceptual design of simple gas turbine engines for different purposes is presented. A choked-flow low-pressure turbine is used that allows reducing the number of stages and gas temperature in the relative motion ahead of blades. Application of such turbines with uncooled blades to reduce the cost of power-limited engines is considered.

Multiparameter studies of the discharge coefficient dependence on the nozzle geometry and the presence of a condensed phase in combustion products were performed. The simulation results obtained satisfactorily agree with the well-known generalized data. The modern computational fluid dynamics methods were shown to be able to refine the generalized empirical relations.

This paper considers an air pressure probe, the head part of which is made in the form of a polyhedron inscribed into a sphere. Wind tunnel testing of the probe models is performed, a mathematical model and an algorithm are constructed to calculate all the altitude and airspeed parameters, and an error estimation is given.

High-precision measurement systems of modern aircraft are studied in this paper. A measurement system with correction in the structure of inertial navigation system is introduced for highprecision aircraft. In the correction algorithms, a linear error model of the navigation system is usually used. With the aim of increasing the accuracy of the navigation system, we propose a nonlinear correction algorithm based on the state dependent coefficient representation of the nonlinear model.

The paper presents a device for spraying the low-melting metal coating, based on the rocket chamber operation principle. The design of the fuel nozzle, pre-mixing chamber, and radial combustion chamber is considered. The processes of electro-spark ignition of the fuel mixture and the flame front stabilization are described. The choice of the critical section area as a place of the coating material feeding in the high-temperature combustion products flow is substantiated.

The technique was developed for studying the noise immunity of electronic systems of unmanned aerial vehicles on the basis of physical modeling. The mathematical models, the scheme of a test bench, and examples of parameter calculation for physical modeling of electromagnetic interference in communication lines under the influence of switching magnetic fields of electric transport contact network are proposed. An example of physical modeling of electromagnetic interference in communication lines is presented.

The location of the center of mass closer to the source of radiation during rectilinear accelerated motion of an aircraft in the absence of gravity and drag forces provides stability of the angular motion. The proposed scheme was analyzed on the basis of the Lagrange–Dirichlet theorem.

This paper considers changes in design of solar panels due to a need to improve reliability and to increase the service life.

The name of the first author of the article should be read as S.A. Samipour.

Affiliation of S.A. Samipour should be read as Tupolev Kazan National Research Technical University, ul. Karla Marksa 10, Kazan, 420111 Russia.