Trim Tab Lower Rivets

[NewGuy]

After the trim tab trailing edge is bent the proper amount and the side tabs are folded over properly but not yet riveted, how do you get to the lower rivets to buck them?

The plans call for AN426AD3-3.5 rivets, but I can?t figure out how you get inside the trim tab to back up the rivets up to buck ?em. Do you just use the MK319 blind rivets from the outside instead or do you ?unbend? the trailing edge enough to get a bucking bar in to back ?em up?

Will unbending enough to get inside work harden the trailing edge enough to promote cracking later?

I?ve searched the instructions and the plans, but don?t see the answer?


Ken Korenek
Arlington, Texas
Empennage almost done
QB Kit on Tony?s trailer and on the way!

 

[Scott Will]

how I did it

Here is a picture of how I squeezed the rivets on the trim tab. I cut the head off a bolt and superglued it to a thin nose no-hole yoke. Take a look here. Worked great!

This is the log entry from that build session:
I was having the hardest time figuring out how to squeeze the rivets on the trim tab hinge, both on the trim tab itself and the elevator. I followed Van's directions but that leaves you in an ackward position to squeeze those flush rivets. I even tried bucking the rivets with Chuck but that wasn't the best of ideas.

So I called in the excellent help of Paul. Earlier in the day we talked about making a stand-off for the thin nose yoke. While he was driving to my house I went to Home Depot to see what I could find. Here's what I came up with.

I bought a cheap cap screw, cut off the threads and polished both sides. Then I CA'd (superglue) it to the yoke and it worked great. The rivet came out nicely.

 

[RyanM]

I did mine this weekend. I don't have any pictures, but i was able to get in there with my longeron yoke and pneumatic rivet squeezer. In order to get the yoke over the flange, I had to the yoke parallel to the trim spar and rotate it in from either end. It takes a little time to figure out how to get the yoke in there, but after that is goes quick. I also placed my trim tab inside of a bench vise, but I didn't close the vice, it just rested in there nicely while I riveted.

Ryan

 

[DGlaeser]

Back riveting...

I believe I back riveted those with a long back rivet set - opened the skins enough to do the job. Opening up the skin to get a tool in there will not work harden the fold because you'll find the metal next to the fold is what actually bends.

 

[bullojm1]

I used a longeron yoke for mine. I used a few AN960-10 washers under one of the flush rivet dies to make it stand taller to clear the wider portion of the rib.