Vytautas Blechertas

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The AH-64 helicopter tail rotor gearbox is a grease lubricated right-angle transmission which frequently leaks through both its input and output seals. An experiment was designed to create a worst-case scenario for a leaking output seal on three different high-life gearboxes, which were to be run for 500 hours in a seeded fault condition. The test objective(More)
—A new concept of nonparametric signal detection and classification technique is proposed using mutual information measures in the time–frequency domain. The time– frequency-based self-information and mutual information are defined in terms of the cross time–frequency distribution. Based on time–frequency mutual information theory, this paper presents(More)
In critical conditions, gears operate with insufficient lubrication and efforts are made to improve the life of these gears against wear. A local gear-tooth defect such as a fatigue crack, pit, or chip weakens a tooth and causes transient events in the system. The magnitude and duration of these events depend mainly upon the severity of the defect and the(More)
— Accelerometer data has been gathered from accelerated conditioning in grease lubricated and lubrication deprived gear meshes in AH-64 helicopter intermediate and tail rotor gearbox, which are commonly problematic components of the Apache helicopter platform. These tests were performed in a controlled drive-train research test bed, simulating drive-train(More)
Several experiments on AH-64 tail rotor drive train components have been performed, and key findings relating to the gearboxes and grease are discussed. In the first case study, an intermediate gearbox experienced three successive thermal events beyond the specified operational limits, all of which were characterized by rapid and unexplained changes in(More)
rotorcraft Vibration Management Enhancement Program. The paper gives an analysis of the CBM concept and its functional layers, such as condition monitoring, diagnostics, prognostics and health management systems, followed by diagnosis and prognosis enabling technologies and concepts; followed by research and development of Health and Usage Monitoring(More)
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