Does anyone know what the best wing mounting method is. I know the original way is they have flush set bolts set into the wing at the bottom. I need to buy new longer bolts as there are only 2 threads poking through the top of the wing with my current bolts. But I think I would benefit from using 3 washers one on each bolt on the bottom to spread the load more and prevent the wing from teatering and use like a hex head style bolt. This wing is a fair bit bigger then my NP AL one i own.

Do you think the idea I have with using non flush blots would create excessive drag ( ie 3 washers with 3 hex heads poking out the bottom of the wing)? Just donno if the wing with flush set bolts would make it rigid enough. Willing to sacrifice a bit of drag for a more secure wing mount.

I had a wing that was attached by M6 screws into a threaded aluminium fuselage. Every time I had a poor launch in on shore conditions and scraped the bottom, I would bend the bolts and cause the wing to sit at an angle. I drilled out the holes in the fuselage and put in M8 bolts with hex nuts. I could detect no obvious issues, but it is a slow foil (top speed of 15 knots).

You got a new wing and the original bolts aren't long enough? And you're worried just getting longer bolts will put too much load on the head and into the wing?

Is it a DIY collection or an actual OEM setup?

I'm guessing that a washer won't have the same area as a conical head bolt, to spread load...

And IIRC you need something roughly like 1.5 times diameter of bolt to have achieved 98% of max clamping force ... Or something like that.

You don't want bolts sticking out it will ride like ****,create drag and most likely make noise.why can't you go somewhere like cost less bolts and get the correct length or longer ones and cut them

It is my own wood wing I made that I'm mounting to the Neil pryde fuse. This wing is slightly thicker where it connects so I will need longer conical head bolts then as suggested above. The tricky part might be making that ressesed pocket for the cone shaped head of the bolts to fit in. I have already drilled the holes...So maybe use a step bit to achieve that cone shape ressesed part or a small enough hole saw to drill it to the depth I need then chisel it out, it might be harder with the hole saw method.

I know you want the wing nice and tight in the fuse but wonder how tight I can tighten the conical bolts down before it splits the wing open it is only pine.
sorry, I only have pics of the top right now. But the bottom is basically flat with three holes for the bolts.

Oh, I see. I think I've read people making their own resin inserts for the bolt holes so you can countersink them (there's a drill bit for that) and then crank then down as tight as.

IIRC the method was a carbon tube in a larger PVC tube, filled with resin, then glassed into the wing...

So yes to longer bolts and countersink the holes, but then you'll be to get FRP in there somehow and I have no idea about that :D

Select to expand quote

Kamikuza said..
Oh, I see. I think I've read people making their own resin inserts for the bolt holes so you can countersink them (there's a drill bit for that) and then crank then down as tight as.

IIRC the method was a carbon tube in a larger PVC tube, filled with resin, then glassed into the wing...

So yes to longer bolts and countersink the holes, but then you'll be to get FRP in there somehow and I have no idea about that :D

Ok great I did not even know they sold something for conical bolts to counter sink. https://www.aliexpress.com/item/4PCS-Nonstandard-Bit-80mm-Cone-Drill-Countersunk-Head-Hex-Reamer-Countersink-Drills-Countersink-Drills-Wood-Drills/32890655916.html
I was thinking of a step bit but would not work nearly as well.
What did you mean by this comment-
"but then you'll be to get FRP in there somehow and I have no idea about that"

Select to expand quote

CAN17 said..

Kamikuza said..
Oh, I see. I think I've read people making their own resin inserts for the bolt holes so you can countersink them (there's a drill bit for that) and then crank then down as tight as.

IIRC the method was a carbon tube in a larger PVC tube, filled with resin, then glassed into the wing...

So yes to longer bolts and countersink the holes, but then you'll be to get FRP in there somehow and I have no idea about that :D

Ok great I did not even know they sold something for conical bolts to counter sink. https://www.aliexpress.com/item/4PCS-Nonstandard-Bit-80mm-Cone-Drill-Countersunk-Head-Hex-Reamer-Countersink-Drills-Countersink-Drills-Wood-Drills/32890655916.html
I was thinking of a step bit but would not work nearly as well.
What did you mean by this comment-
"but then you'll be to get FRP in there somehow and I have no idea about that"

When you countersink the holes, you'll have to get fiberglass (FRP) down in the countersink, won't you? Without adding thickness to the wing that will cause the bolts to stand proud...

This is why I probably won't ever make wings :D

Drill into the fuselage from the side and insert a barrel nut......if there is not enough room for that, the u stuck dealing with aluminium... but 2 threads ain't enough!!

Select to expand quote

dachopper said..
Drill into the fuselage from the side and insert a barrel nut......if there is not enough room for that, the u stuck dealing with aluminium... but 2 threads ain't enough!!

Drilling into the aluminum is not needed there is already a threaded part built into my fuseledge. I just need to counter sink into the bottom of the the wing where the 3 holes are. I need to use the conical drill bit to make the counter sink so the conical bolts sit flush with the bottom of the wing. One of My original question was will the wing be secured( ridgid) enough with the 3 conical bolts, without the wood getting split open with the bolts clamping on it. Sorry if I was not clear enough explaining the situation.

I suspect the bolts will pull through the timber wing pretty quickly. You might have to sandwich the wing between a metal plate and the fuselage. A bit of 4mm stainless would do the trick. It will protrude, but won't slow you down (wing doesn't look that fast)

Select to expand quote

oldbones said..
I suspect the bolts will pull through the timber wing pretty quickly. You might have to sandwich the wing between a metal plate and the fuselage. A bit of 4mm stainless would do the trick. It will protrude, but won't slow you down (wing doesn't look that fast)

Yah i guess so. But wouldn't 3 stainless steel washers and hex heads or whatever style bolt clamping it against the fuseledge do the same thing. "Wing doesn't look that fast" don't worrie it's only going on a windfoil and Kitefoilers are obviously faster then windfoilers anyway ...which makes me care less about 3 hex heads poking out the bottom of the wing. Hopefully it wont ride too **** or brake.

Select to expand quote

CAN17 said..

oldbones said..
I suspect the bolts will pull through the timber wing pretty quickly. You might have to sandwich the wing between a metal plate and the fuselage. A bit of 4mm stainless would do the trick. It will protrude, but won't slow you down (wing doesn't look that fast)

Yah i guess so. But wouldn't 3 stainless steel washers and hex heads or whatever style bolt clamping it against the fuseledge do the same thing. "Wing doesn't look that fast" don't worrie it's only going on a windfoil and Kitefoilers are obviously faster then windfoilers anyway ...which makes me care less about 3 hex heads poking out the bottom of the wing. Hopefully it wont ride too **** or brake.

Nice thick washers should do the trick

Select to expand quote

CAN17 said..

oldbones said..
I suspect the bolts will pull through the timber wing pretty quickly. You might have to sandwich the wing between a metal plate and the fuselage. A bit of 4mm stainless would do the trick. It will protrude, but won't slow you down (wing doesn't look that fast)

Yah i guess so. But wouldn't 3 stainless steel washers and hex heads or whatever style bolt clamping it against the fuseledge do the same thing. "Wing doesn't look that fast" don't worrie it's only going on a windfoil and Kitefoilers are obviously faster then windfoilers anyway ...which makes me care less about 3 hex heads poking out the bottom of the wing. Hopefully it wont ride too **** or brake.

Have you glassed the wing yet? Can't tell from the pictures...

You could:
Drill holes with a Forstner bit, big enough to fit a bit thick washer and deep enough to hide the bolt below the level of the wood -- then fill it with wax when you ride for a temporary streamlining, or resin for a permanent fix.
Countersink the holes, a shallow Forstner bit hole for a thick washer, drill out and counter sink the washer so it all sits flat.
Do the same above but with a plate. You'd need to dremel out the plate "hole" to fit it nicely (or just not bother with that part of it--I'd still want to countersink the bolt heads though.)

Option three would be the most fiddly, but might actually be the best result. You're going to apply a lot of side-to-side force on that wing and fuselage mounting point, and I'm wondering it's that going to be more of an issue than what you're worried about in this thread...

Select to expand quote

Kamikuza said..

CAN17 said..

oldbones said..
I suspect the bolts will pull through the timber wing pretty quickly. You might have to sandwich the wing between a metal plate and the fuselage. A bit of 4mm stainless would do the trick. It will protrude, but won't slow you down (wing doesn't look that fast)

Yah i guess so. But wouldn't 3 stainless steel washers and hex heads or whatever style bolt clamping it against the fuseledge do the same thing. "Wing doesn't look that fast" don't worrie it's only going on a windfoil and Kitefoilers are obviously faster then windfoilers anyway ...which makes me care less about 3 hex heads poking out the bottom of the wing. Hopefully it wont ride too **** or brake.

Have you glassed the wing yet? Can't tell from the pictures...

You could:
Drill holes with a Forstner bit, big enough to fit a bit thick washer and deep enough to hide the bolt below the level of the wood -- then fill it with wax when you ride for a temporary streamlining, or resin for a permanent fix.
Countersink the holes, a shallow Forstner bit hole for a thick washer, drill out and counter sink the washer so it all sits flat.
Do the same above but with a plate. You'd need to dremel out the plate "hole" to fit it nicely (or just not bother with that part of it--I'd still want to countersink the bolt heads though.)

Option three would be the most fiddly, but might actually be the best result. You're going to apply a lot of side-to-side force on that wing and fuselage mounting point, and I'm wondering it's that going to be more of an issue than what you're worried about in this thread...

Sounds like a good idea using the forstner bit to counter sink the bolts with a washer. Will likely buy hex head bolts and stainless steel washers. Yes side to side movement may be any issue, I won't really know how tight it feels connected until I buy bolts. But it sits in the fuse pritty nice. As you can kinda see in the pic I had to channel out a part for the back of the fuseledge to sit in the wing. I did not fiber glass. Have thought about it a lot. It's very interesting stuff on getting the perfect finish in this thread below and all the science behind it and maybe a bit too much sometimes for the average Joe like me with a sander and drill.
www.seabreeze.com.au/forums/Kitesurfing/Foiling/Polish-makes-you-go-Faster--?page=1#29

If you don't glass it, it's going to be too flexible and soak up water, isn't it?!