Wing Box J stiffeners HELP

[JoeB]

Section 13 1st page.....

I have the "long and short" wing box J stiffener cut to size..but I am unclear on how they are susposed to be mounted on the Spar. is the 1/16th spacing from the long stiffener, or the "nesseled" short one. am I just stacking the two on top of each other? and are they both flush to the end of the spar flange?


thanks.

Joe

 

[CharlieWaffles]

Common confusion. The short is nested inside the long and both are flush with the end of the spar flange (near the wing root) and the long is 1/16" proud of the top of the flange.

You are really just lining up the stiffeners and using the spar as a really really expensive drill guide to pre-drill the holes in the stiffeners that will eventually line up with the skins.

 

[JoeB]

Thanks, .........simple task for a simple person

 

[fehdxl]

Be sure you have the spar extensions on the spar when doing this...else your j channel wil be about 9" too short. Don't ask me how I know. Jim

 

[ppilotmike]

Me too!

I also suffered through this confusion. The J-stiffeners should each be flush with one end of the spar (the short is flush with the inboard edge of the spar flange, and the long is flush with the outboard edge of the spar flange, with extension installed). The overlap is where they are "nested", and as I recall it's only about 4 inches or so of overlap. As said before, you're using the spar as a hole guide to drill the stiffeners, which will actually be installed later across the wing ribs, attached to the skins. Hope this helps. By the way, there are two places in the drawings that show you which holes NOT to drill in the stiffeners. The second one (i.e. a few pages back) is clearer in my opinion, but you'll still need a magnifying glass to make sure which holes don't get drilled. If you think this is fun, wait till you get to countersink all those buggers!!