Fwd Top Skin

[Scott_F]

Had a major wrestling match today trying to get the F-7106 forward top skin clecoed down (QB slider). The center ribs went ok, but when I would get one side clecoed to the longeron, the other side would be out of alignment fore/aft. I finally managed with some strategic clecoing and serious tugging to get it down, but it makes me wonder about all the residual stress. Did anyone else have difficulty getting this skin on initially, or is it kind of like the wing/tank leading edge ribs - just a bear to do the first time?

Another question - the drawing calls for an AN-960-6 washer between the F-7108A rib and F-7108B angle. What is an AN-960-6? I couldn't find one listed in the fuselage hardware inventory. I have a 960-10 in there for now and it looks like it provides enough room for the roll bar brace.

 

[Charles in SC]

My skin was hard to get on as well. I found that when I built the upper forward section, i had the center rib a little to high. I do not remember how I did this but I ordered another center rib from Van's and did it right the second time.

 

[Scott_F]

Charles,
Thanks, I had a problem with the center rib initially also. The F-7108B angle was drilled a little far down on the center rib, thus lifting it up a little. Even after I fixed that, it was still a bear getting the skin clecoed to the sides.

-s

 

[marchudson]

No problem here

I just finished riveting the top forward skin. Went on fairly easy. I started from the center and worked my way towards the edges. Every once in a while, I had to use an ice pick to carefully center the holes. Other than that no problem.

 

[pierre smith]

We used ratcheting straps....

...around the fuselage and put a 1' X 1" pieces of wood under the straps at the upper fuselage longeron, near the hole we were trying to cleco. There are screw type clecos with much better holding strength for areas like the upper longeron.

Best,

 

[Rick6a]

I just finished riveting the top forward skin. Went on fairly easy. I started from the center and worked my way towards the edges. Every once in a while, I had to use an ice pick to carefully center the holes. Other than that no problem.

Excellent advice from Marc. Start by inserting clecos in all the holes along the most centerline rivet row. Then continously insert clecos working outboard inserting a few clecos at a time on both the left and right side of the skin in a more or less even manner. Using that technique, the load on the skin and structure needed to align the skin can be greatly reduced. The only thing I would add is to 100% cleco the skin into place and only then.... again starting from the centerline and working outboard, remove only 2,3 or 4 clecos at a time to shoot the rivets.

 

[Caveman]

Been there... done that

Yes, I had the same trouble, too. This was actually one of the handful of pieces that I ruined and replaced. I used a combination of Pierre and Marc / Rick's suggestion to finally tame the beast.

Joe