Wyniki wyszukiwania - BazTech

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Selected problems of transmission wear of the Mi-24 helicopter

Gębura A., Zientalski K.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

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2015

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nr 37

25--44

EN

The hypothesis of mutual, destructive impact of the worn upper bearing of the WR-24 transmission on the Mi-24 helicopter's gearbox was stated. The Mi-24 is the only helicopter operated in Poland, in which the gearbox is mounted outside the main transmission – in the centre of the transmission shaft, between the main gearbox and the tail rotor. Damage to the gears in the gearbox of power generators is equivalent to termination of the tail rotor's drive. Such a termination immediately causes rotation of the body in the direction opposite to the direction of rotation of the main rotor. It is associated with the loss of lift and steering. It may lead to a disaster. Such an incident occurred in January 2011 in Afghanistan – both authors participated in its investigation. The authors, taking into account very good, almost legendary combat properties of the Mi-24, and their research of the specifics of wear and tear of the transmission elements, they think that, first, funds for development and implementation of the drive unit monitoring system should be made available specially for this helicopter. For this purpose, the authors propose to use the FAM-C method. It is characterised with significant ergonomics. Thank to this, multiple kinematic pairs can be observed simultaneously, and, therefore, the relationships between them as well.

2

Evaluation of Steering Disks in Mi-17 and Mi-24 Helicopters by Means of the Fam-C Method

Kurdelski M., Gębura A.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

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2013

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nr 33

127--158

EN

The paper deals with selected issues related to operation of steering disks designed for helicopters that are currently in operation of the Air Force of the Republic of Poland. The attempt is made to present a prediction of hazards to the transmission gear of that helicopter where the forecast is based on a theoretical analysis of mechanical phenomena as well as the statistical and diagnostic analyses. The major attention is paid to the opportunity to diagnose hazardous locations of the helicopter steering disk with use of a non-destructive FAM-C method originally developed by ITWL. The method is based on tracking of frequency modulation parameters generated by the on-board AC generator. The examination does not require the installation of any additional sensor since the transmission is subjected to neither additional load nor distortions of the rotation speed occur. The authors of this study disclosed the initial results from diagnostic measurements as well as snapshots taken during the disassembling of steering disks from Mi-24 and Mi-17 helicopters that were operated under heavy duty conditions of military missions in Iraq and Afghanistan. They also suggested an easy and cheap method for field checking of the steering disk bearing by photogrammetric measurements. It is also demonstrated that the method of diagnostic investigations can be also spread onto other helicopter makes and types.

3

Capabilities of the FAM-C method to diagnose the accessory gearboxes and transmission -train assemblies of the MI-24 helicopters

Augustyn S., Gębura A.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

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2012

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nr 30

199-220

EN

The study has been intended to present some selected service-imposed issues with the transmission system of the Mi-24 combat helicopter. An attempt has been made to present predictions about possible threats/hazards to the transmission system of this helicopter. The forecast has been based on the FAM-C analysis of changes in instantaneous frequency against time and, to some extent, on mechanical measurements of disassembled structural components/subassemblies. The greatest emphasis has been laid on capabilities to identify and diagnose locations in structural components of the Mi-24 helicopter (where many and various hazards may arise) using the non-destructive diagnostic method FAM-C developed at ITWL (Air Force Institute of Technology). The method has been based on the tracking of parameters of modulation of airborne alternator produced frequencies. The testing requires no extra sensors, since the built-in airborne AC, DC, and tachogenerators themselves are the diagnostic transducers. While taking FAM-C measurements, the transmission system experiences no extra loads or rotational-speed distortions.

4

Mi-24 wymagania systemu monitorowania transmisji

Gębura A., Karczmarek K.

Journal of KONBiN

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2011

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No. 4 (20)

235--252

PL

W artykule przedstawiono materiały pomiarowo-badawcze umożliwiające zbudowanie układu monitorowania stanu technicznego zespołu napędowego na wzór układu HUMS stosowanego w śmigłowcu transportowym CH-47 Chinook. Polski system byłby „wzbogacony” danymi uzyskanymi przy pomocy metody FAM-C. Metoda ta bazuje na pomiarze modulacji częstotliwości napięcia wyjściowego prądnic pokładowych. Przedstawiono hipotezę wzajemnego, destrukcyjnego oddziaływania zużytego łożyska górnego przekładni WR-24 na skrzynkę napędów śmigłowca Mi-24.

EN

Measure-research information providing to design a monitoring system for a power unit is presented in the paper. The monitoring system is similar HUMS used onboard CH-47 Chinook helicopter. The Polish system would be “enrich” data provided by means of FAM-C method. This method is based on a measurement of output frequency modulation of aircraft’s alternators. A hypothesis of manual destructive influence of a worn out upper bearing of Mi-24 helicopter’s WR-24 gearbox is presented.