Author Topic: Go Foil 14 Flip Shim  (Read 2332 times)

red_tx

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Go Foil 14 Flip Shim
« on: June 23, 2021, 04:42:20 PM »
So I have been avoiding shim talk until now, but when I see jondrums and beasho typing about it, I pay attention..

Beasho, I thought you posted a pic but I cannot find it.

Today I tried a credit card shim on the front screw of my 14 flip. The rig wheelied wildly out of control on my shoulder high drops. I could feel it wheelieing even before I caught the wave, as I was paddling(trying to catch the wave). I know guys are saying that the lift shims on tail wings can be unstable in larger drops.

Will someone please post a pic of thier 14 flip lift shim or send the link to the thread. I cannot find it.

I am looking for a tiny bit of lift, mainly to help pumping. 

Thanks in advance.
-red

gone_foiling

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Re: Go Foil 14 Flip Shim
« Reply #1 on: June 24, 2021, 10:12:04 PM »
Which pedestal are you using? What are trying to achieve?
Addicted to foiling at the moment.
My shenanigans on insta @gone_foiling

red_tx

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Re: Go Foil 14 Flip Shim
« Reply #2 on: June 25, 2021, 06:57:13 AM »
Hi Gone.

Sorry, I am using the short pedestal and trying to create a tiny bit of lift at takeoff and then during pumping.

I made a credit card shim and put it under the front bolt(closest to mast) and the thing wheelied out of control. I obviously shimmed too much but a credit card is pretty thin.

I just wanted to *see* what is working.

I understand this setup gets squirrly on larger waves. I have experienced this first hand.
Thanks
-red

Beasho

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Re: Go Foil 14 Flip Shim
« Reply #3 on: June 25, 2021, 08:54:22 AM »
Shim looks like this.

The shim works great in smaller, slower surf AND for Wing-Dinging.  Because we all go pretty slow on the wing-ding until you are way advanced.

bigmtn

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Re: Go Foil 14 Flip Shim
« Reply #4 on: June 25, 2021, 05:41:52 PM »
try using an aluminum can to make the shims. Easy to stack them to make them thicker or thinner.

jondrums

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Re: Go Foil 14 Flip Shim
« Reply #5 on: June 27, 2021, 03:39:29 PM »


Sadly, the GoFoil pedestal system is really crappy.  You're mounting a curved wing to a flat surface and it is nearly impossible to get a repeatable mounting position.  As you can tell, I'm pretty sour on the GoFoil system even if the wings are pretty magical.

Shimming the tail gives you so much variation with such a small adjustment.   I am messing with tail pitch constantly and I've got to where I know what I personally like - it may not be what other people like!  Here's some thoughts:

* If you can afford to fiddle, get or make an incidence meter.  I made my own using a $30 china-tastic digital level from amazon and some woodworking. https://www.horizonhobby.com/product/anglepro-ii-5-in-1-digital-throw-incidence-meter/EFLA280.html
* On GoFoil and Takuma (probably same on other systems) I like the tail somewhere between 2-5 degrees pitched down in relation to the front wing. 
* Higher pitches are exclusively to improve pumping and have downsides if you're not pumping.
* The lowest angle (2deg or less) will have the least drag - this is actually pretty noticeable.  A lot of people would say it "feels faster", which is just the sensation of slipperyness or lack of drag.  It should have a little bit higher top speed - we'd have to ask Beasho for the data.  If you're not pumping, you'll probably want to stick with the lower pitches.
* At the 3-5 degrees, you'll need to move your stance forward to counteract the increased PITCHING MOMENT of the tail.  This is NOT more lift, although to a casual observer it feels like more lift.  The tail pitch actually results a rotational moment, which pushes the tail down (and nose up).    This comes at the expense of increased drag.  However, it is magical for pumping because it will bring the board's up as you unweight.  Half a degree can make a noticeable difference in pumping.

Based on your comments, you probably need to either move your foil back in the boxes a cm or two or move your stance forward a bit.   A single credit card shim will ride fine and pump much better once you adjust your weighting.
« Last Edit: June 27, 2021, 03:41:01 PM by jondrums »

jondrums

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Re: Go Foil 14 Flip Shim
« Reply #6 on: June 27, 2021, 03:42:07 PM »
forgot to mention that if you go too small on the angle everything gets unstable in pitch.  I haven't really explored this limit too much besides a few times where I didn't enjoy it at all.

steamroller

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Re: Go Foil 14 Flip Shim
« Reply #7 on: June 27, 2021, 08:15:42 PM »
agree with jondrums and it potentially gets even worse with the Kdmaui tail...if you get thebpitch corrent that thing is magical...but if you get it wrong!...ooooh myyyyu GOSH! that thing can really  SUK!...after testing testing for about an hour i finally got it to the point where i can dial it in perfect every time with a self developed tightening procedure byt it takes some trial and error...


 


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