Why so few washers?

Discussion for Waiex builders on specific plans page experience. These posts are limited to technical suggestions such as assembly order, challenges, or techniques related to specific plans pages.

Why so few washers?

Postby kevinh » Thu Aug 06, 2015 6:14 pm

Hi ya'll,

This is my first sonex project and now as I'm getting into building the spar I have a question:

Why do the plans not show washers under nuts? For instance, the aileron bellcranks or the WIX-W16-06 wing root attach assemblies. I thought that it was almost always good practice to include a washer underneath the nut, so that tightening the nut doesn't damage the aluminum and distribute the load. I'm okay with not using washers here, but this seems different from what I'm used to.

Kevin
Taildragger Waiex in progress, tail done, wings done, about to mate wings to fuse,
then cowl, canopy, paint (photos): flush rivets, turbo aerovee, acro ailerons
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Why so few washers?

Postby Sonex1517 » Tue Aug 11, 2015 9:25 pm

Kevin

It appears no one replied. I would check with technical support on this.

Robbie
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Re: Why so few washers?

Postby Bryan Cotton » Tue Aug 11, 2015 9:43 pm

I think Tony Bingeles had a good article about this. I will see if I can look it up sometime.
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Re: Why so few washers?

Postby DCASonex » Wed Aug 12, 2015 6:19 pm

If memory servers me right, Sonex does not call out washers specifically, but does call for enough to be installed to bring nut to proper position on bolt. It seemed to me that the bolt length specified was sometimes longer than needed to be (never shorter) and required 3 washers, at which point I often went to next shorter bolt length.

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Re: Why so few washers?

Postby NWade » Wed Aug 12, 2015 7:41 pm

DCASonex wrote:If memory servers me right, Sonex does not call out washers specifically


I'm pretty sure they always call out washers when giving the list of fasteners & qty of components for an assembly. And they definitely do show the washers on the drawings; but you have to look carefully to see them in some cases (especially underneath bolt-heads in the side-view drawings).

Note that there are a couple of locations where there are no washers because the nut is intended to help lock something in place (such as some of the components on the aileron bellcranks).

However, I agree with David that in a few cases the plans specify a bolt that was longer than appropriate and would have required 4+ washers to prevent the nut from bottoming out. In those events, I did the same thing as him and used the next-shorter bolt of the same diameter.

When in doubt, though, always contact Sonex tech support!

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