I beam inside the spars

[49clipper]

anyone have a picture of this beam inside the spars?
Jim

[TJay]

just out of curiosity here why do you need a picture. it looks like an I inside of an O

[49clipper]

Curiosity, and because a picture is worth a thousand words. Is it full length? I am impressed with the strength of the Kitfox wing and being an engineer, I always want to know why.
Building my last airplane is a big decision and I want to get if right.

[Dave S]

Jim,

The I beam does not go full length of the spar. It fits inside the spar centered over the lift strut attach point to strengthen the higher stress portion of the spar while keeping the added weight to a minimum.

With your engineering curiosity (which describes a lot of us:)) you would be interested to know that the build manual also includes instructions to cut a fish mouth into the web on each end of the spar insert - that provides a graduated support where the insert ends to increment the stress at that point.

For some reason, I never took a photo of the inserts?????:mad:

Dave S

[49clipper]

Thanks Dave, that is exactely how I thought it would be (just over the strut area. Looks like a great wing.

[t j]

Fish mouths finished. I built a third wing for my model 4 few years ago. This is the incerts that were beig supplied for all models at that time. Much heavier than the orginals that came with my Kit in 1994.
8112

Looking in the root end of the right wing front spar. This is the lighter weight incert that came with my Kit 1200 maximum GW model 4.
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The blue tape marks where the ends of the I Beam are.
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