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Estudo de implementação do procedimento de equilibragem dinâmica na aeronave Chipmunk MK20
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Abstract(s)
A Força Aérea Portuguesa (FAP), através do sistema de armas Chipmunk MK20, cumpre a missão de instrução elementar dos alunos pilotos aviadores. Por forma, a garantir a prontidão da frota, é vantajoso integrar no seu programa de manutenção, ações baseadas na monitorização da condição, entre as quais a análise de vibrações. É desígnio desta dissertação, estudar a implementação de um procedimento de equilibragem dinâmica na aeronave, através da adaptação do sistema VibraPac PRO.
Dado que não estava previsto pelo fabricante qualquer procedimento de equilibragem, foi necessária a modificação do prato que segura o cone da hélice. Deste modo, era possível reduzir o desequilíbrio anómalo, através da instalação de massas corretivas. O estudo desta modificação exigiu a determinação do material constituinte do prato e a simulação computacional, no ANSYS, dos esforços provocados pelas massas instaladas, nos furos do prato modificado. Assim, estimou se que o limite de massa a instalar seria 15 in, em 4 furos distintos.
Seguidamente, procedeu-se à validação do sistema VibraPac PRO, utilizado até à data na aeronave Epsilon TB30, com a definição dos componentes da cadeia de medição, e da sua organização. Recorreu-se a um calibrador de acelerómetros, tal como a testes num simulador de avarias, para validar a cadeia de medição e o software, que resultaram igualmente no aprimoramento do sistema.
Por fim, foram realizados testes na aeronave, dos quais se verificou a eficácia e eficiência do procedimento de equilibragem. Foram reduzidas as vibrações na 1ª harmónica do veio da hélice, dos 0,26 ips para os 0,032 ips, valor abaixo do limite estabelecido pela FAP. Adicionalmente, realizaram-se controlos vibratórios com o VibraPAC PRO que demonstram a redução da vibração no motor, com aquisição de vibrações noutros regimes de operação da aeronave.
The Portuguese Air Force (PoAF), through the aircraft fleet Chipmunk MK20, has the mission of elementary instruction of aviator pilots. In order to ensure the aircraft availability to fly, is beneficial integrate in its maintenance program, actions based in conditioning monitoring, of which the analysis of vibrations. It is purpose of this dissertation, study the implementation of a propeller dynamic balancing procedure on the aircraft, by the adaptation of the system VibraPac PRO. Since it was not foreseen by the manufacturer any balancing procedure, in order to install the balance weight, it was necessary to modify the spinner back plate. Thus, it was possible to reduce the unbalance, through the installation of corrective weights suggested by the VibraPac PRO software. The study of this modification required, the determination of the material of the plate and a computer simulation, in ANSYS, of the stress caused by the loads in plate new holes. Thereby, has been estimated the weight limit to be 15 grams, in four different holes Some alterations were performed to the VibraPac PRO, used to date in the aircraft Epsilon TB30, with the definition of the components of the measuring chain. An accelerometer calibrator was used, such as tests in a malfunctions simulator, to validate the measuring chain and software, which resulted in the improvement of the software. Lastly, tests were performed in the aircraft, of which was verified the effectiveness and efficiency of the balancing procedure. The vibrations in the first harmonic 0of the propeller shaft were reduced from 0,26 ips to 0,032 ips, below to the limit establish for the PoAF. Additionally, vibratory controls were performed with the VibraPac PRO, which proved the reduction of vibrations in the engine, with the acquisition of vibrations in other operation regimes.
The Portuguese Air Force (PoAF), through the aircraft fleet Chipmunk MK20, has the mission of elementary instruction of aviator pilots. In order to ensure the aircraft availability to fly, is beneficial integrate in its maintenance program, actions based in conditioning monitoring, of which the analysis of vibrations. It is purpose of this dissertation, study the implementation of a propeller dynamic balancing procedure on the aircraft, by the adaptation of the system VibraPac PRO. Since it was not foreseen by the manufacturer any balancing procedure, in order to install the balance weight, it was necessary to modify the spinner back plate. Thus, it was possible to reduce the unbalance, through the installation of corrective weights suggested by the VibraPac PRO software. The study of this modification required, the determination of the material of the plate and a computer simulation, in ANSYS, of the stress caused by the loads in plate new holes. Thereby, has been estimated the weight limit to be 15 grams, in four different holes Some alterations were performed to the VibraPac PRO, used to date in the aircraft Epsilon TB30, with the definition of the components of the measuring chain. An accelerometer calibrator was used, such as tests in a malfunctions simulator, to validate the measuring chain and software, which resulted in the improvement of the software. Lastly, tests were performed in the aircraft, of which was verified the effectiveness and efficiency of the balancing procedure. The vibrations in the first harmonic 0of the propeller shaft were reduced from 0,26 ips to 0,032 ips, below to the limit establish for the PoAF. Additionally, vibratory controls were performed with the VibraPac PRO, which proved the reduction of vibrations in the engine, with the acquisition of vibrations in other operation regimes.
Description
Keywords
Chipmunk MK20 Equilibragem dinâmica ANSYS VibraPac PRO Dynamic balancing VibraPac PRO
Citation
Publisher
Academia da Força Aérea