LE fit to ribs, wing cradle

[rjcthree]

Sorry to post such a mundane topic, but I am at my wit's end.

I'm working the outboard LE section, cleckoing ribs to the skin. I cannot manage to massage the skin such that I can clecko the top and bottom of the skin to the ribs. The manual says work top first, from LE back, then bottom, LE back. Where I can reach both rib and skin with one hand, clecko pliers in the other, I can make this work, but nowhere else. I've jockied padding, posture, board over the where the ribs mount to the spar for uniform pressure, and all I've manged to do is realize I may need to deburr the holes a little more (who needs stitches when you've got CA?) and bend a couple flanges - and scratch the inside of the LE skin, GRRRR.

Honestly, I'm looking at this and thinking the cradle is not the way to go.

How did you do this?

Thanks, Rick 90432

 

[Brantel]

These are tough and I have put them together with and without a craddle and I can tell you it is much easier to do with the craddle. It is even harder once you dimple them.

One thing to watch out for is that you do not pull too hard with the cleaco or an awl to get the holes to line up because it can cause the hole to elongate.

Is your craddle the right shape and does it squeeze the skin together into the correct possition? Did you remove all the bumps from the front of the ribs? Did you flange the ribs at a good 90 degree angle?

The tanks are just as hard in this area. They are even worse because you have to do this with the proseal on them.

 

[Will Womack]

One trick that worked for me on the leading edges and for the tanks was as follows:

Start with the skin lying on the bench (no cradle). Put two clocoes thru the skin and into each rib. Put these two clecos into the two most forward holes on the bottom of each rib. Then flip the skin over (with the two clecos per rib hanging over the edge of your table. Now put two clecos per rib in the top most forward holes (this will take some pushing on the ribs and pulling on the skin). Once you have those four clecos into the forward holes, the other holes are easy. Insert the remaining clecos and THEN put the whole thing into the cradle.

 

[rjcthree]

Thx

Will, I think that was what I was looking for. I did recheck flanges, bumps and whatnot, and I'm ok there.

I'm not building my tanks, I'm having those done, as I fear the proseal demons and most of my building sessions are limited to <2hrs - not a good combination. ANd for the $, it seems like a fair deal.

I'll give this a try, and hopefully get back later.

Thanks,

Rick 90432

 

[apatti]

Rick,

This is indeed a tough spot. One thing to keep in mind is that once you have "trained" all the ribs as to where they fit, they get a little easier with each disassembly/assembly cycle. So, when you go to do this for the last time and have the proseal spread all over the place, they end up going in fairly easily.

Now, getting them in for the first time... I am working on two year old memory here, but I will try to recall some of things I did.

First, wear work gloves on the hand manipulating the rib. By the time I was at the stage you are at now, I had cut up my hands pretty well. Also, make sure the ribs are fluted and the flanges bent properly. Also, clean up the flange edges especially up at the leading edge. This helps them slide a little easier without scratching the skin quite as much.

I recall using the wing cradle but moving the tank skin around so the the rib I was working on was not close to one of the wooden cut-outs of the wing cradle. That gave me a little flexibility.

When I inserted the rib, I would push it down as far as I could trying to make sure the holes in the leading edge were somewhere close to where they need to be. I would then try to put a cleco in the aft most hole on the bottom. I would usually have to pull the skin away from the rib a little and insert the cleco at an angle and let it pull the rib down into place. With that cleco in I did have to keep constant pressure on the rib with my hand.

I would then turn my attention to the leading edge and try to insert a few clecos on the bottom at the leading edge. To help me line up the holes, I placed my fluorescent shop light inside the skin near the rib. That way, when I looked at the skin from the outside, I could easily see which way the rib was off (once I got it close to where it needed to be). After I inserted five or six clecos in the leading edge, I would remove the cleco I had inserted in the aft most hole. Then I would finish running the clecos from the leading edge aft on the bottom. I would then work on the top. With the bottom clecoed in place, it was a little easier working on the top. Again, having the shop light inside made it much easier to see from the outside where the holes in the rib were.

As memory serves, this is what worked for me. I do remember being very frustrated with this process. It took a lot more force to get those ribs in there than I thought. And, yes, I did scratch up the inside skin at the leading ege. But that is why God invented scotchbrite pads.

I hope this helps. Good luck and enjoy. Remember, it could be worse. You could not have an airplane to build.