Категория: Aeronautics

Influence of GTE rotor vibrations on technical condition of inter-shaft bearing

UDC 004. 588 BBK 74.5

Yu. A. Karavaev

S. A. Khodatskiy

A significant number of aircraft engines taking out early from operation are associated with inter-shaft bearing failures. Possible causes of such failures are violations of their lubrication and cooling conditions. The article presents the results of experimental studies to assess the effect of reducing the performance of the oil tube with bending vibrations of the rotor on the thermal state of the inter-shaft bearing.

During the turbofan engine operation, its shaft co-performs bending vibrations due to the imbalance of the rotor. In this case, the oil tube, placed inside the engine shaft, will also make bending vibrations, which can be one of the reasons for reducing oil consumption through the oil tube with a significant level of vibrations. In this case, the working temperature of the inter-shaft bearing may increase significantly.

Keywords: aircraft engine, inter-shaft bearing, vibration velocity, bearing temperature, GTE oil system parameters.

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Comparative analysis of a mathematical model of the turbine gas temperature sensor of the turbocharger of a helicopter gas-turbine engine based on regres-sion analysis and neural networks

UDK 629.7:681.324 BBK 39.551-01-07 S21

A. A. San’ko

A. A. Shejnikov

The article presents the results of a comparative analysis of mathematical models of the turbine gas temperature sensor of the turbocharger of a helicopter gas turbine engine based on regression analysis and on a multilayer neural network. The inexpediency of using a multilayer neural network as a mathematical model of a gas temperature sensor is proved. The optimal type of the mathematical model of the gas temperature sensor is selected by the criterion of the minimum error of the output parameter calculation.

Keywords: gas turbine engine, rotor, mathematical model of gas temperature sensor, helicopter, neural network.

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The influence of quasi-sinusoidal inhomogenuities on the characteristics of double- and three-hop ionospheric reflections

UDC: 621.371.33 BBK 39.57

A.I. Agaryshev

Nguyen Minh Giang

M.A. Portnov

The article presents the results of researching the influence of ionosperic inhomogenuities on the maximum observed frequency (MOF) and the angles of arriving the radiowaves reflected two and three times from the ionosphere (2F2 and 3F2 modes). The authors present the calculated МOF and angles of arrival of decameter radio waves using the method of equal MUF under conditions of quasi-sinusoidal inhomogenuities. The results of calculations are compared with the results of measurements.

Keywords: maximum usable frequency, maximum observed frequency, inhomogeneity of the electron concentration, characteristics of double- and three-hop ionospheric reflections,  the angles of arrival of 2F2, 3F2 modes.

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Analysis of the influence of aerometric instruments and pitot – static probes faults on flight safety

UDK 629.7 BBK 39.56

A. Shomankov

The main types of failures and faults of pitot – static probes and aerometric instruments are determined and the causes of their occurrence are revealed. The results of the analysis of these faults influence on flight safety are presented.

Keywords: faults, mean flight time between failures, aviation event, difficult situation, probability of occurrence inflight abnormal circumstances, air crash, accident.

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The influence of a crew information support level on safety flights

UDC 004.588 BBK 74.5

Karavaev Yu. A.Khodatskiy S. A.

The article formulates general approaches to the impact assessing algorithm formation of the crew information support level at the stage of landing gear failures localization on safety flights. The possibility of using these algorithms to assess the functional efficiency of the crew in the process of various aircraft systems failures compensating is shown through the specific flight incidents examples.

Keywords: safety, crew information support, failure localization, a special case.

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Promising fasteners for aircraft structures of carbon composites

UDC 629.7.015.4.023 BBK 39.48

Sazhin N. A.Sazhin A. N.

The authors consider benefits and drawbacks of existing (traditional) fasteners (metal rivets) for airframes built with application of carbon composites.  Schematic designs of promising patented fasteners (PCM rivets) and patented technologies of their mounting in aircraft structures, experimental full-size designs of the fasteners of polymeric composite materials (carbon composites) providing improvement of their mounting are given. 

Key words: fasteners, mounting, rivet, carbon composite, polymeric composite material, blind riveting, aircraft structures.

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Signal demodulation for the secondary radar channel of ADS–B system

UDC 621.396.74 BBK 39.571.5

Lezhankin B. V., Mezhetov M. A., Turincev S. V.

Aircraft flight safety is largely dependent on the performance of systems having various purposes. One of the systems is ADS-B intended for air traffic management by constructing trajectories of aircraft motion with efficient use of airspace. The analysis of main methods of designing the equipment, demodulating and decoding the signals in data links is therefore a relevant objective which can increase the efficiency of air transportation at the required level of flight safety.   

Key words: ADS-B, systems of symbol synchronization, quadrature demodulator, quadrature signal, hardware-software receiver, preamble detector.

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Use of Pareto chart for developing recommendations on aircraft reliability

UDC 629.3.083 BBK 39.0163

Barsukov A. G.

The author considers a methodology of integrated approach to the rationale and implementation of recommendations on aircraft reliability with the use of Pareto chart.

Key words: flight safety; aircraft; reliability; failure; fault; Pareto chart.

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Kinetics of creep fracture of vt-20 titanium planar samples

UDC 629.7.015.4 BBK 39.52

Zabobin V. V.

The article demonstrates the results of experimental research of fracture kinetics for samples made of VT-20 titanium sheets under alternate stresses and at elevated temperatures. Dependences of crack growth rate on load parameters are obtained. The mechanism of regarding the influence of temperature and load non-stationarity on VT-20 fracture kinetics is proposed.

Keywords: kinetics, creep, crack, supersonic transport airplane, SST, titanium alloy.

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Stochastic discrete mathematical model of aerometric instrumentation control by data of flight recorders

UDC 629.7 BBK 39.56

Shomankov D. A.

The presented mathematical model is based on complexation and evaluation of heterogeneous flight parameters which are registered by data recorders or other concentrators that provide their post-flight processing by linear discrete Kalman filtering algorithms. The presented materials are based on previously obtained scientific results and are a continuation of the paper published in IIAJ «Crede Experto: transport, society, education, language» (2017, № 2, p. 115–125).

Key words: complexation, error estimation, control, controlled state, diagnostic sign, seminatural experiment.

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