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Low pitch flutter like noise. Kingtech 210

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Low pitch flutter like noise. Kingtech 210

Old 10-29-2023, 08:05 PM
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acw
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Default Low pitch flutter like noise. Kingtech 210

I have an Ultra Bandit EVO with a full bypass. The plane has around 15 flights now and is performing well. One strange thing is a low pitch flutter like sound which is only present when I apply about 1/3 power and more. This appears to come from the pipe or the turbine itself.

Any idea regarding what this is and if any fix is possible?
Old 10-30-2023, 02:46 AM
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BarracudaHockey
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We had an Hummingbird with an 85 making that sort of noise and it turned out to be a broken blade on the turbine compressor wheel
Old 10-30-2023, 05:17 AM
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There’s a guy at my club that had one making that noise as well. He switched from diesel to Kero and it mysteriously went away. There’s at least one more I’m aware of that also makes that noise. Both different brands of turbines and both have made it since new, and both different size engines.

I would like to know the actual cause as well.

Old 10-30-2023, 09:14 AM
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scoeroo
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Possible combustion harmonic at part throttle ..... hence disappears at higher throttle
Old 10-30-2023, 11:23 AM
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What tailpipe on turbine to tailpipe tube gap?
Old 10-30-2023, 11:50 AM
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acw
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Good question. It is about 26mm. Looks like the turbine is a little far... Moving the turbine closer to pipe would require some work. Do you have experience indicating this could be the issue?

Old 10-30-2023, 12:28 PM
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Dave Wilshere
 
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This fully ducted.? If so 26mm is about right.
Old 10-30-2023, 12:46 PM
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acw
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Yeah, it is a full bypass. There is a 25x8mm hole on top of the turbine which is covered with aluminum tape. I start to wonder it this could be vibrating...
Old 10-30-2023, 10:08 PM
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Try flying it with the bypass top off for one flight.
It won’t be your hole/tape.

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