| Résumé | The National Research Council (NRC) was requested, by the Department of National Defence (DND), to assist in determining the cause of repeated failures of acceptance tests of CT64-820-3 turboshaft engines after overhaul and repair. NRC personnel visited the test cell at the Naval Engineering Test Establishment (ΝΕΤΕ) in Montreal to witness an acceptance test. No serious problems with the test cell were observed. It was noted that the secondary airflow in the cell was below recommended levels, but it is unlikely that this would cause a significant power loss to the engine.
Temperature distortion was noted at the compressor inlet which can reduce the compressor and overall engine efficiency, but it is unlikely cause more than 1% reduction in power. Increasing the secondary airflow will reduce the temperature distortion. Problems measuring inlet mass flow were observed. This measurement does not affect the acceptance results, but would provide valuable information for diagnosing the engine. Solutions are discussed in the body of this report.
Performance analysis was limited by the small number of measured parameters. Results from the instruments on the engine indicate that the air flow is reduced on the engine which failed the acceptance test compared to the one that passed. This is likely due to compressor problems. Engine efficiency was also reduced, and would be partly due to the air flow problem in the compressor, but reduced turbine efficiency could also be contributing. |
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