Upgraded to the new Axis (F)ART 999, carbon mast, and 420 tail. Best set up for sure BUT the whistle is killing me!

I ran it with my old 380 tail initially and Im sure it started once I put that 420 on.

Axis advised sanding tail along the forward facing (fatter) edge at 45 degrees from below with 220 grit.

Sanded once, tried. No change. Sanded again, a bit harder....still 'whistling dixie'.

For the love of Mike, does anyone have any suggestions - Sand harder? Sand somewhere else? Cut down/off tips?

My deepest apologies to everyone with real problems out there.....

You need to do a "Donaldson"
On a stab, half-round the up trailing edge (a stab is an inverted airplane wing, the intrados is on top).

www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/The-definitive-solution-to-fins-and-foils-whistling-humming--The--Donaldson-trailing-edge-

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stevet73 said..
Upgraded to the new Axis (F)ART 999, carbon mast, and 420 tail. Best set up for sure BUT the whistle is killing me!

I ran it with my old 380 tail initially and Im sure it started once I put that 420 on.

Axis advised sanding tail along the forward facing (fatter) edge at 45 degrees from below with 220 grit.

Sanded once, tried. No change. Sanded again, a bit harder....still 'whistling dixie'.

For the love of Mike, does anyone have any suggestions - Sand harder? Sand somewhere else? Cut down/off tips?

My deepest apologies to everyone with real problems out there.....

Not sure about foils but with windsurfing fins the solution was to sand the trailing edge at 45 deg. One swipe with 300.

Thanks guys. Another mate also suggested the trailing edge...not front edge of tail. I thought axis would have steered me in the right direction....but maybe not on this occasion.

I'll get the sandpaper out again

You can try the Donaldson way or the Levitaz way


But for sure it is the trailing edge.

Great explanation from onofoil on why this is happening here: www.instagram.com/tv/CWHfQjRvwwS/?utm_medium=copy_link

As mentioned above do the Donaldson trailing edge , works great . It's your tail not the mast .

You're using 220 grit?! That will leave a rough finish, finish it with 800 then 1200 grit.

Sanded the trailing edge of my 420 and it no longer whistles.

Many thanks. Did a mini Donaldson method, no change. Did a harder Donaldson method....seems to have settled a tiny bit. Will do a third Donaldson with some 800 to finish.... fingers crossed

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stevet73 said..
Many thanks. Did a mini Donaldson method, no change. Did a harder Donaldson method....seems to have settled a tiny bit. Will do a third Donaldson with some 800 to finish.... fingers crossed

Friend of mine had same issue with his setup, tried everything - then changed angle of attack (shimed his stab) & the noise was gone.

If all else fails, maybe give that a try mate.

Great tip toppleover! Thank you.
Glad to hear I'm not the only one.....

Are you sure they Said to sand the "Leading edge"? I have never heard that-its sounds to me like signals got crossed there.

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martyman said..
Are you sure they Said to sand the "Leading edge"? I have never heard that-its sounds to me like signals got crossed there.

Yep. I even sent them a photo with my finger pointing to the spot they were telling me before I did it....as even I didn't think it was right. I actually messaged access asking why they gave me such inaccurate information and everyone here was straight away correct. Got no response.

Good thing is, the whistle has indeed settled. Took a few 'sand, test, re-sand' efforts but now I only get a bit of whistle when pumping....which I can deal with. So thanks all.....

Hey, can someone confirm for me that I should be sanding the top trailing edge of my new KD13R (on a Kujira setup) that needs require's the Donalson treatment please ?

Yes

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kobo said..
Yes

Thanks kobo, weird my standard KD13 was silent the 13R is a screamer but seems to be faster & pump/turn better.

Messaged Kane about the noise & he mentioned that he treats all his wings for this before sending but some may need more than others.
Also confirmed to sand top of trailing edge with 320 grit.

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toppleover said..
Messaged Kane about the noise & he mentioned that he treats all his wings for this before sending but some may need more than others.
Also confirmed to sand top of trailing edge with 320 grit.

Yeh , the thinner the profile and narrower the chord the more likely it will sing.
I ended up using a fine steel file to get even angles and tapered it from about 8 mm in,then all the way to the edge.I ended up with a sharp edge which I then had to softened with some wet and dry. After the file I used 600 then 1000 to finish. Took me 3 attempts to silence it totally.