UDK 629.5.03-843.8 BBK 74.5

Karavaev Y.A.

Hodackij S.A.

The article presents general approaches to forming an estimation procedure of the residual operation life of the bypass turbojets operated on civil aircraft for long periods of time by taking actual operating conditions into account. With the example of D-436-148 aircraft engine having the standard control program the authors analyze how the size of turbine-blade tip clearances influences the rate of exhaustion of a bypass turbojet module – the gas turbine. A fraction of moving blade damage on takeoff is proposed to be used as a parameter defining the rate of exhaustion of the gas turbine.

Key words: gas-turbine engine lifetime, turbine-blade tip clearances, durability of moving blades, creep.

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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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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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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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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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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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