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Lift 170 Classic harmonics

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riddim1
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Lift 170 Classic harmonics

Postby riddim1 » Sun Dec 27, 2020 11:42 pm

Hoping for some insight from other Lift users on a harmonics issue I have been trying to remedy.

Have owned the 170 Classic for about 5 months now. Love the wing and the mast for my style of riding but cannot shake the harmonics (humming) it produces at the upper speed ranges.

I have been sanding the trailing edges of the wing first per the Lift video. This has only provided marginal improvements so I’ve moved onto sanding the stabiliser ( from the underside of course). Again, no improvement.

Have been conservative with the material I’ve removed but the trailing edge of the wing is getting dangerously sharp now.

A friend has suggested it may be the mast that needs sanding. Another has suggested I may now need to flatten-off the training edges a little. I understand this is not common for Lift Classic wings so I’m after some other ideas.

Any help appreciated.

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Re: Lift 170 Classic harmonics

Postby Dwight » Mon Dec 28, 2020 12:05 am

The Lift mast was the cause of my humming.
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riddim1 (Mon Dec 28, 2020 9:31 pm)
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geokite
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Re: Lift 170 Classic harmonics

Postby geokite » Mon Dec 28, 2020 6:35 am

Apply tape to the suspect sections you think might be causing the humming. It will make the foil fly like s@it, but it will isolate the cause.

I have the 170 classic and the 170 surf, and the only noise I've had was from a 34 tail. Took a lot of sharpening to get rid of it.
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riddim1 (Mon Dec 28, 2020 9:31 pm)
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Breze
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Re: Lift 170 Classic harmonics

Postby Breze » Mon Dec 28, 2020 9:34 am

Hi riddim. I have no Lift foil but had humming on diy foilwings and masts.."At the trailing edge the parted water comes together and a wrong edge will creates a annoying whistling and creates water turbulences wich slows you down" says Simon from Riftboards in his sanding blog https://www.riftboards.com/sanding-your-hydrofoil ( read the comments below). Also George from Deltafoil and Mario from Levitaz(attention, he means high pressure side) have quite the same technics.
Which differs from the Lift video (he works on both sides and makes the TE perhaps too sharp)
As you sharped the TE, i would square it off with 400 grit to get a 0.5 mm edge. Hope it helps
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riddim1 (Mon Dec 28, 2020 9:31 pm)
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riddim1
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Re: Lift 170 Classic harmonics

Postby riddim1 » Tue Dec 29, 2020 9:28 pm

Thanks all for the comments.

The tape is a good idea which I hope to try out today.

Will also square-off the trailing edges and see how that goes. Failing this, will progress to sanding the mast.

I’m sure I’ll get there eventually

riddim1
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Re: Lift 170 Classic harmonics

Postby riddim1 » Tue Jan 05, 2021 12:08 pm

Yep, turned out to be the mast causing the ‘humming’. A very light sand both sides of the trailing edge @30 degrees solved the issue.

Thanks for the great advice again.
Hope this helps someone else as well.
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SMJ (Wed Jan 06, 2021 12:48 am)
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Daversj
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Re: Lift 170 Classic harmonics

Postby Daversj » Sat Jan 16, 2021 11:23 pm

My lift 170 classic hums at speed also. I bought it used for cheap in great condition so am not complaining. Love the foil, super stable and pretty fast. Much less pitchy than the Moses 633. Haven’t gotten around to sanding it yet to get rid of the hum. I was going to start with the mast.... Looking forward to your results.


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