Tip Up Aft Skin Fit Problem

aparchment · Post by **aparchment** » Sat Feb 07, 2009 6:31 pm

Not sure what is going on guys. I was fitting the top skin (F-774 - tip up part #) just behind the baggage compartment, and it isn't aligning with the holes in the F-706 bulkhead. As I cleco the skin on everything is okay until I start clecoing up the 706 bulkhead toward the top of the fuselage. The 786A J-stiffeners are pushing the 706 bulkhead forward of the holes in the top skin so that they don't align. It appears that they are too long, but they meet the length requirements specified -- 50 3/16"

Has anyone else had this problem? I am not sure if the stiffeners are too long or the skins are not correct. I am tempted to trim the J-stiffeners shorter, but don't want to act too quickly.

Can anyone help?

Antony

aparchment · Post by **aparchment** » Sat Feb 07, 2009 6:36 pm

Chad - It looks like you had the same problem. Do you remember how much you cut off the J-stiffeners? Have you had any other fit problems as a result?

Antony

cjensen · Post by **cjensen** » Sat Feb 07, 2009 7:53 pm

I did cut my down a bit...maybe a quarter inch or so. Didn't cause any problems whatsoever. Trim it up, and move on bud!

aparchment · Post by **aparchment** » Sat Feb 07, 2009 8:11 pm

Thanks Chad:

I didn't do the work on the J-stiffeners since this is a quick build fuse, and in general they don't look right where they attach to the bulkheads. It looks like where they attach aft they cut way too much of a relief in the stiffener.

Although the top of the stiffener is riveted in place with the bulkhead, there is a 3/4" gap between the side of the stiffener and the bulkhead. You can see it in the pic below. Doesn't that seem like too much?

I have also posted a pic of the misalignment that would result if I don't cut the J-stiffener.

Antony

cjensen · Post by **cjensen** » Sat Feb 07, 2009 8:13 pm

Links ain't werkin...

aparchment · Post by **aparchment** » Sat Feb 07, 2009 8:14 pm

Yah, not sure why. Troubleshooting it now.

There we go. Got it. I used the wrong URL from Imageshack.

cjensen · Post by **cjensen** » Sat Feb 07, 2009 8:30 pm

Cut it, and make it work. They just stiffen the skin, and the tab is just used to attach it to the bulkhead. Doesn't matter that there is 3/4" space between the vertical part of the stiffener to the bulkhead. The work is being done between the bulkheads, not at them.

Interesting that the J channel tab is riveted on the outside of the flange of the bulkhead in the QB. It's sandwiched between the skin and bulkead on the SB kit...

aparchment · Post by **aparchment** » Sat Feb 07, 2009 8:56 pm

Will do. I will cut it down to size and keep moving. Wasted a lot of time mulling this over.

Thanks for the help Chad.

Antony

cjensen · Post by **cjensen** » Sat Feb 07, 2009 9:55 pm

No prob Antony!

charlie · Post by **charlie** » Sun Feb 07, 2010 5:38 pm

Just started exploring rivetbangers, looking for tips & info. I hope no one minds input from a forum newbie.

I know this is a little late (a year...) for this thread, but thought I'd point this out for future viewers.

The 1st pic shows the J-stringer under the flange tab on the bulkhead. On my -7 kit, the tabs on all the bulkheads were bent so that the stringer wes between the skin & the tab. I can't remember if I had the length problem with the stringers.

Charlie

Post by **Spike** » Sun Feb 07, 2010 6:00 pm

Welcome Charlie

RivetBangers.com

Tip Up Aft Skin Fit Problem

Tip Up Aft Skin Fit Problem

Chad - you too?

This Looks Right

got it

cut it and move on