Stabilator skins not fitting?

[dtibbo]

So I've riveted both stabilator skeletons, and attempted to cleco the skins to the skeleton.

The plans do a good job telling me the curved side is the top side, so I've aligned the skin that way. It fits fine on the spars, but every rib is about half a hole off vertically. I could probably bend the ribs back into shape with a block of wood and a mallet, but I was wondering if there might be something else going on here.

Phone just broke otherwise I'd have photos to post.

Also, I'm searching for a technical advisor near Winston-Salem, NC.

[wingnut99]

It hasn't been but a few months since I assembled mine and if I remember right the spars were drilled but you were supposed to mark a line down the center of the ribs and manipulate the skeleton until you saw,the line on the ribs through the predrilled pilot hole in the skin and then drill the holes in the rib using the pilot holes in the skin. I can't recall having holes predrilled in the ribs to line up with the skins.

[dtibbo]

I've got pre-drilled holes in the -B kit. Thanks for your reply, I did have to do that process for all seven control surfaces.

I took a few days to think about it, had an inkling, and checked it out. Misalignment was self-induced. There's nine flush rivets on the rear spar that required dimpling, and the dimple die had contacted the ribs. Since it's off alignment in the direction of the rib web on only one side by the slightest amount, it looks like I've moved the bend of the web throwing off alignment. I'll just put the rib back into position. Funny what a little time away working on flaps can do.

[Concorde]

Hi David,
I have been Building a Sonex in Greensboro for the last 4 years. The EAA advisor for central NC was Charles Harrison, unfortunately he passed last year and I don’t know of anyone else . Just take your time and follow the plans and you will be just fine .
Good luck with your build.
Ben

[dtibbo]

Thanks. I've gotten in touch with the Hickory EAA Chapter and they'll be sending someone next week!

[jrs]

What did you do to dimple the holes in that spar ? Is there a specific die or easier method. Only think at sonex is for skins. May have already made a mistake as I updrilled the holes before I saw that they were to be countersunk.

[Bryan Cotton]

I have ground down dies before to fit tightly spaces. Or, make a female die out of a thick piece of aluminum. Drill and countersink the scrap and use a flush die to back up your home made tool.

[Bryan Cotton]

Also, check out this thread:
viewtopic.php?f=34&t=695

One last thing - I have dimpled many #30 holes rather than the suggested #31 or #32. As long as the rivet sets tightly I think you are good to go. I've never had a problem.

[jrs]

Thank Bryan. Buddy coming by with some dimples tomorrow and will try to squeeze them out gently. They don't need to be pretty just functional.