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OS 61SF rmp dropping

Old 08-11-2007, 06:07 PM
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Default OS 61SF rmp dropping


I have an older Os 61SF that has a problem. It will turn an APC 12x6 prop at 11900 for 30 - 45 seconds wot after the initial start/warm up the slowly back down to 11500 and remain there. IH know it is not a heat issue bacause it is on my test stand with nothing blocking the airflow. I am using coolpower 15% an an OS A3 plug. Any ideas or has the engine reached the end of its usefullness ?


Old 08-11-2007, 06:25 PM
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Default RE: OS 61SF rmp dropping


Actually at test stand is the worst for cooling because all the engine is getting is airflow from the prop and that is not enough. I'd say the rpms you are getting is pretty resepctable so I'd mount it in the plane and see if it still drops off on a long vertical upline. If it does then your are a tad too lean on the high end, you may even be a tad to lean on the high end on the test stand

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