Had my board/AFS W95 foil upside down and laying on top of, and connected to, the sail on the beach. That has always worked in the past to keep wind from doing anything to it. But today was really gusty and the wind got under the board and sail and threw it in the air. The front wing hit the sand and pulled the screw anchors out of the fuselage (see pictures). Is there a way to repair that damage? The F770 wing looks good, the stabilizer is good, as is the rest of the T-bar mast.

thedoor said..

Sandman1221 said..
Had my board/AFS W95 foil upside down and laying on top of, and connected to, the sail on the beach. That has always worked in the past to keep wind from doing anything to it. But today was really gusty and the wind got under the board and sail and threw it in the air. The front wing hit the sand and pulled the screw anchors out of the fuselage (see pictures). Is there a way to repair that damage? The F770 wing looks good, the stabilizer is good, as is the rest of the T-bar mast.

bummer so the fuse failed before the wing or screws?

All I can think of which I have never tried is heli-coils for M8 and then bore out the wing to M8

I would probably just order a new fuse though.

Other option would be to expoxy the wing onto the fuse permanently

Yeah, the front screw just bent, other two screws were fine. Was thinking of filling holes with epoxy, then taking a screw wrapped in teflon tape and screwing it in to force the epoxy into the voids, then use a C-clamp to press the screw/anchor back into the socket, remove screw and use rubber mallet to tap the surface flat, do for all three using slow setting epoxy. Then put a piece of Saran wrap over fuselage and carefully screw wing on without fully tightening the screws, but enough to make sure wing is level and flush with fuselage.

Also contacted Bruno at AFS to see what he thinks, maybe they have seen it before and know how to repair it.

Hey WillyWind thanks, will find out soon if that can be done, Bruno from AFS already got back to me, yes it can be repaired, and Julian will be contacting me on how to do that. Big relief!, but that fuselage is so solid/strong I figured there must be a way to fix it.

No more leaving board attached upside down to the rig, realized the wind direction probably changed in a +15 knot gust and hit the mast so the fuselage and wing leaned over and acted as a lever to tilt the board over, and then the wind got under it and the sail.

segler said..
Oh man, Sand, we all live in deathly fear of that. Hope you can repair it. AFS (like my AFS-2) are one of only a handful of manufacturers that make carbon fuses. Even Moses uses aluminum. Let us know how it goes.

Segler, will do, just waiting to hear back from AFS on the specifics of the repair, but I think what I posted would work too. If they were epoxied in after the the fuse was made, like WillyWind thinks, then it should be reasonably easy to repair. If it was aluminum, I guess helicoils would work, or just replace the relatively inexpensive fuse.

What is remarkable is the higher aspect F770 wing is good, no sign of any damage or cracks, but it is solid carbon, even though the front stainless steel screw bent quite a bit (see pic). Most other wings with foam cores would probably have cracked under the force of the impact.

Grantmac said..
I've had foam cored wings do the same thing onto rock without damage (Supercruiser), but also solid ones chip (Slingshot TC68).

Never damaged an aluminum fuselage although I have heard of a Starboard cracking at the mast mount but that was replaced under warranty.

Carbon is great for some things but not others. It is at least very repairable.

Grantmac, what do you think of my repair plan below? Waiting to hear back from AFS, hopefully hear from them during the coming work week.

Was thinking of filling screw holes with slow setting epoxy, then taking a screw wrapped in teflon tape screw it in to the hole to force the epoxy into the voids, then use a C-clamp to press the screw/anchor back into the socket, do for all three. Then put a piece of Saran wrap over fuselage and carefully screw wing on without fully tightening the screws, but enough to make sure wing is level and flush with fuselage. When epoxy sets in screw holes, remove screws and wing, then work more epoxy into/under the "broken crust" around the screw holes and then clamp crust back down.

Looks like they made the fuselage, drilled holes for the screw inserts, epoxied the inserts in, and then finished with a wrap of carbon weave "crust" on the fuselage.

I like the idea of the Chicago bolts. LP uses them, too. If I ever damage the inserts on my AFS-2, I will use them for the repair. Good idea.

I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1

Grantmac said..
I think your repair will be at least as weak as the original arrangement. An improvement would be to use the Chicago bolts which Starboard uses to attach their fuselages to their masts. You'd be drilling straight through the fuselage.

Grantmac, Well it took a real wallop to cause the damage, I mean the kit went into the air and landed 30 feet down the beach on the front wing tip in the sand, not something that would occur under normal use. In normal use the wing is being pushed up into the fuselage, so normally there is not a lot of pressure on the female inserts.

Will look into the Chicago bolts, thanks

FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1

FarNorthSurfer, yeah, now I know why all the kite foilers here place their boards right side up with nose on the sand facing the wind and the foil behind with the wing flat on the sand jacking up the tail of the board.

Let's see what AFS recommends, they had today off, so should know soon. But filling the female threaded holes with epoxy, then forcing the epoxy into the cavity 1st with the screw, then 2nd by pressing the screw/female barrel assembly back into the cavity should work, as long as it goes in straight, and they should since they were only pulled out a little. If done right, the repair should be good and look fine.

Subsonic said..
Its a bit of a compromised situation from the get go. Carbon is brittle, not so good at holding onto a little stainless insert that has to hold onto a wide, high aspect wing and all the associated leverage. It'll need a significant amount of carbon back over the top of the anchor insert to hold it in position, given the small surface area that the bolt has on top for the Carbon to hold in. A couple of layers won't do it. The bolt will sheer straight out at the first sign of twisting that the wing will inevitably put on it whilst foiling.

Im sure AFS will have done their engineering homework and established that their construction was up to the loads of foiling, I'd say the best bet is wait for their response if they have a way to mend what's broke safely. They'll know their own construction better than anyone else, and what's needed to make a repair strong enough. Failing that, the "Chicago" bolts look like the best compromise, followed by as much carbon over the top as you can afford to put there, with a few layers all the way round to finish.

Subsonic, thanks for the detailed response, will see what AFS says, but drilling though the fuselage for the Chicago bolts seems like a no-no since it would weaken the fuselage in my opinion. But adding layers of carbon on top of the repaired inserts, if possible, sounds like a good idea.

Sorry, i was looking at the wrong thing. The tappex self tapping inserts that farnorthsurfer posted was what i was looking at. Not the chicago bolts.

i wouldn't want to drill it all the way through either.

Sailrepair said..
I would speak to AFS (not the easiest thing to do) .

The new AFS fuselages are designed with this problem in mind in that you replace the insert from the opposite side of the fuselage. I believe it is the same principle with the previous fuselages but require more work. You would drill down carefully from above and remove the insert and replace it.

I have the AFS dealers maintenance manual so I will see what it says and let you know.

Sailrepair, great!, please let me know what the AFS maintenance manual says.

the problem with my idea to press the female barrel back into the fuselage is that the barrels were not pulled out straight, at least the center one is crooked. Maybe it will straighten out when it is pressed in? see picture, used a new screw.

FarNorthSurfer said..
I have the same foil and after reading this will try not to leave it on the beach like a old wave board again! That's a bummer.
Also be interested in what AFS come back to you with.
I used to be an aircraft engineer with composite experience and think I might be looking for something like this to do the repair. It would be best using a drill press to get the holes right and I didn't see where in the world you are. These things could be hard to source.
www.tappex.co.uk/product_category/titanium-threaded-inserts?cn-reloaded=1

Those tappex titanium inserts look very very nice, be good if all ali fuses came with those installed,
Does anyone know how it cost each for them ?

Freeflight said..
I think if any drilling is done to install inserts to the carbon fuse it is doomed, they are barely strong enough to start with so if you start making bigger dia holes the end will be near
Best to just press the current ones back in place with epoxy, put a couple of layers of cloth over them and keep an eye out for future movement, when that happens order a new fuse

Freeflight, well good to hear someone agrees with my plan, will see if I can put pressure on the high side of the screw (screwed into the insert) to force insert back in straight.

So first step is getting the female inserts straight, used a 100 mm M6 screw to do that. Used a hex key at first, but was worried it could damage the threads, the 100 mm M6 screw gave enough leverage to straighten out the worst insert, in the center position. After straightening on top, before on bottom, both screws were fully threaded into the insert. Actually bent the 100 mm M6 screws straightening out the inserts, all are now straight.

Second step is to pour epoxy into the inserts and use a screw wrapped in teflon tape to force the epoxy into the cavity below the inserts.

Third step is to screw a 40 mm flat head screw into the insert and use a vise to press the screw/insert back into the fuselage, while hopefully forcing the epoxy up and around the outside of the now slightly loose inserts.

Last step, screw wing onto fuselage with still soft epoxy, to make sure everything is aligned properly. There should be enough resistance on the inserts to keep them in the fuselage while I screw the wing on, without tightening up the screws, but enough to seat the wing. Will use two levels to make sure wing is parallel with stabilizer (wing on one level, stabilizer on the other level). Will probably grease screws for this step, teflon tape may cause to much resistance and turn the inserts..

Any comments welcome, looks like I am on my own on this repair.