I decided to pick up some KT Atlas wings but wanted to stick with my mast so I got a custom fuse CNC’d, trouble is the the front wing doesn’t seem to seat well at all.
People with KT foils how solid is the connection?
your bolts are probably too long and bottoming out
I checked that before assembly, they both went right down below the line where the wing would be. Also if you watch the full video you can see I ended up stripping a few mm of thread off the front hole which can’t happen if they are bottoming.
whatever the cause, just so one thing is clear (more to readers than you), that is an issue with something you have done with the custom fuse, as no foil on the market has ever had that much play
You gotta talk to who made your fuse.
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To be fair we still have to establish that it’s the fuse (most likely) and not the wing that’s at fault. I did notice some less than perfect finish in the seating slot on the wing as well.
And yes, this is not how a foil should be by any means.
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It could be bottomed out or stripped threads, low quality bolts, or not enough torque when assembling.
Bottoming out the bolt can cause stripping as you can weaken or strip the threads when tightening when there is no space for the bolt to go. Make sure the bolt has at least 6 threads and room for the head to sit a few mm below the level of the wing.
Make sure the bolts are nice and tight. You can crank on them pretty hard with an L key. Inadequate preload on the bolts will open the connection and bend the bolt back and forth, stretching pretty quickly. Over torquing the bolts a bit isn’t too bad with this connection as it will slip forwards slightly under repeated high load, reducing the strain on the bolt.
Use high quality bolts. The KT foils are included with 316 stainless bolts, which have a significantly higher yield load than the more common 304. Titanium or a higher grade of steel will also work. This becomes more important on the higher span wings like what you are riding.
The last thing to check would be for cracking in the wing countersink. On some foils without a solid center I have seen this kind of play happen when the countersink surface separated from the rest of the wing and sinks into the core below. This is very unlike in this case since the center is solid carbon.
You may have already compromised the threads of the aluminum fuselage and it could be worth dropping a helicoil or 2 in the front connection for peace of mind.
Hope this helps!
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Thanks for the info Kane.
Basically it’s teetering on either the front screw or the back screw, so instead of locking in they are fighting each other. You can tighten it up, but once you pump it, it comes loose right away. I’m pretty sure the AoA of the front wing is incorrect as well as you can see (in the full video) how angled up my board is while pumping and in this video how the angle of the front wing changes like 2° depending if it’s tight on the front screw or back screw.
Wow that is incredible. I am really curious to figure out how that went wrong. Will send you a DM
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Wow I’m interested in an axis mast (nolimitz v2 ) to kt custom fuse. I like my mast too much to abandon it , and $$$ of switching brand.
why don’t you file the fuse down until the wing sits flat?
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Can you find a shop or someone around your area that have a KT fuse? That way you can check if it does the same thing? If it have a tight fit with original KT fuse, then there is something wrong with your custom fuse.
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I’ve located one guy locally who has a KT foil, haven’t heard back from him yet though. I live in a city of 3M people and we really only have one physical shop that sells foils and they only sell Lift and North.
I checked the seat of the wing for flatness and it does appear to have a small teeter on one side:
I’m not sure of the angle the screw holes are supposed to be but it seemed odd to me they weren’t vertical
Perhaps talk to the guy who made the fuselage for you, and BTW, you wrote that “decided to pick up some KT Atlas wings…”, if you have more than one wing, does this problem occur with all front wings, or just one?
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My Atlas 960 has been delayed over a month now, hopefully it will come in mid May I’m told.
Thanks for the photo, that looks more like what I would expect.
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The card rocking like that is definitely not normal though. That area should be flat and nicely level, on both sides.