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| Governor not getting to requested RPM https://www.spirit-system.com/phpBB3/viewtopic.php?f=20&t=2363 |
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| Author: | showmeflyer [ Sun 31. Dec 2017 0:35:54 ] |
| Post subject: | Governor not getting to requested RPM |
I have 2 magnets with same polarity facing a Spartan sensor on my nitro fan. Max rpm set to 2500 and sensor divider set to 2. Idle 1 throttle curve is flat 68 for requested rpm of 1700. Idle 2 is flat 74 for requested rpm of 1850. This is changing in the test screen and actual rpm is displayed with engine running at idle. Also getting 2 active signals from the magnets for each revolution of the fan. In flight I am never getting to the requested rpm. Jeti-Spirit telemetry shows while hovering with no stick inputs Idle 1 is around 1950 and idle 2 is 2200, verified with optical tac and never gets close to requested rpm. There is no hunting or overshooting just goes right past the requested rpm and stays there. Spirit log shows governor engaged once and the rest of the log is all good health messages. I have tried about all combination of response and hold settings and rpm filter from 4-8. I have leaned the carb and my rpm increase slightly and richen the carb the rpm will decrease so I think it is just using the flat throttle curve and no governor. Any help will be greatly appreciated. |
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| Author: | ZeXx86 [ Mon 01. Jan 2018 17:00:10 ] |
| Post subject: | Re: Governor not getting to requested RPM |
Hello, if there is Governor was engaged message, then Governor is active. If the RPM is always higher than requested, it could be caused by: a) No load (blades off - probably not the case if you are seeing it while flight) b) Throttle servo is not able to push with the carb arm freely (are the push rods moving smoothly?) c) Spoolup Rate is too high? d) Governor Response is too high e) Throttle Frequency too low? I recommend to decrease Governor Response first (you can start at 1) and verify what frequency the servo can handle. Then increase the frequency if possible. Then you can check the push rod if there is no friction. Adjusting needles for more rich mixture can help as well. If spoolup rate will be slower, then it has longer time to find that it reached requested RPM and not overshoot it. Now it seems that the time is too short and mechanics/carb is reacting slower than anticipated. With a poor mixture there is always higher afinity to overshoot the RPM. |
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