SS wing spar strut fittings

[jrevens]

I'd sure appreciate some input from other SS builders. I got the "pre-rigged" wing option, & therefore the lift-strut attach fittings were located on the spars & a couple of pilot/locating holes drilled by the factory on each fitting/spar. The fittings as built are not exactly like shown in the assembly manual, in that they do not contact the surface of the spar in the area directly below the ears that the strut attaches to. In fact there is a gap of approximately 1/16" in that whole area on all 4 fittings when seated on the spars. The rest of the surfaces of the fittings fit against the spar tubes fine.The book calls out a couple of rivets installed in that area on the front fittings in order to tie into the flange of the I-beam inside the spar tube. Have other people seen this on their fittings, and if so did you still install the rivets in that area, perhaps using a shim to fill the gap?

[Tom Waid]

This photo may help.

http://tropicaltuba.com/Kitfox%20Project/images/145.jpg

Notice that I placed the hose clamp against the small tab the extends from the center of the bracket.

My adventure with mounting the lift strut brackets is here (http://tropicaltuba.com/Kitfox%20Project/Kitfox3.htm#Permanent attachment of the Lift Strut Brackets.).

[jiott]

I had to slightly open up (bend) the brackets so they would fit down against the spar. Even then there probably was a small gap. I wouldn't worry about a small gap because it will get totally filled with Hysol when you do the final install and riveting.

Jim

[jrevens]

This photo may help.


Notice that I placed the hose clamp against the small tab the extends from the center of the bracket.

My adventure with mounting the lift strut brackets is here (http://tropicaltuba.com/Kitfox%20Project/Kitfox3.htm#Permanent attachment of the Lift Strut Brackets.).

Thanks Tom, but the problem is that my picture shows them just as they were fitted by the factory. You can see that I have rivets inserted in the holes that were drilled by the factory. Trying to pull down the fittings against the spar, even if they would go down further, would badly miss-align those holes. Pulling against the tab with a clamp might bend that tab down, but still wouldn't bring the center of that section any closer- there will still be a substantial gap between the fitting and the spar in the area where the 2 rivets are supposed to go. It's just the way my fittings are built.

[jrevens]

Tom,
In looking at the pictures on your website, it looks like you may not have installed the 2 rivets that I've been talking about, which are shown on the center-line of the front fittings in my construction manual (one of them is the alignment witness hole drilled by the factory, and the other is drilled by the builder). This is on the front fittings only. I also don't see the other extra rivets (4 for each fitting) that my manual shows on the rear fittings (these holes are also supposed to be drilled by the builder, and pick up the legs of the internal I-beam - they aren't drilled in the fittings at the factory). Those are not shown on any of your pictures, that I can see.

Jim,
Thank you also... I agree that it probably isn't critical, but it's going to be a pretty thick layer of epoxy between the fitting and spar tube, like I said, about 1/16" or a little better. I may have to use longer rivets. I'll be interested in what John McBean has to say about it when I (hopefully) can talk to him tomorrow. Widening the fitting out & reforming it to the spar tube isn't possible in my case, as the fittings were already "fitted" & located by the factory as part of the "pre-rigging" option that I got.

[Tom Waid]

Thanks for pointing that out. I've always been someone who meticulously reads the instructions but, this one got away from me. It would not be hard to install these rivets, even with the covering on. I'm weighing my options.

All the very best

[AirFox]

4298
Does this picture help?

[Esser]

John, did you ever get a reply from John McBean? I am in the same boat as you right now.

[Jfquebec]

do you try to change right front bracket right to left...maybe it's can be better...

[jrevens]

John, did you ever get a reply from John McBean? I am in the same boat as you right now.
Yes, I did. John said it was OK. The rivets furnished in the kit were also long enough to use in the center where the gap is - at least in my case. Those fittings are made differently than they used to be in years past, where the piece that wraps around & is attached to the spar was all one solid curved piece.

[P Johnson]

I am about to drill those four rivet holes, apart from keeping the four builder drilled holes inline with the rivets in the I-beam, are there any other dimensions such as spacing, as I cannot find any?

The manual does not say to mix micro balloons with the Hysol on the spar strut fittings but it does for the spar reinforcement fittings and when dissimilar metals are used, is this just a typo omission or do they not want micro balloons in that joint?

Paul

[alexM]

You're correct there are no dimensions for those rivets, but do keep them inline with the I beam rivets.

My old manual specifies use of flox (not microballoons). Looking at the online manual right now I see it doesn't say that anymore. If your lift strut attach brackets are powder coated (they almost certainly are) where they contact the aluminum then separation of the dissimilar metals is already assured.

[P Johnson]

Thanks Alex,

What have others done with powder coated spar strut fittings, micro balloons or not?

[Benbell4140]

I cannot remember who I asked at the factory but I did not use micro balloons. Just don’t scuff the fitting powdercoat down to metal is what I was told.


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