RV-10 trim tab and pneumatic squeezer fail, user error

[Thunderpig]

Trim tab shenanigans so far...

The bending was a nightmare, eventually found some good double sided tape and they came out okay. Started on the right tab, couldn't quite figure out how to get the rivets done using everything I could think of, ended up deforming the two pieces that form the attachment to the cables and the worked out the process for back riveting them and the spar. Piano hinges are all drilled and ready to go...

The riveting at this point should be straightforward...pneumatic squeezer. Yet, just about every rivet ended up off-center. After drilling out my third crappy rivet, the hinge is now unusable and everything needs to be reordered.

Question for the group...I checked Sec 5 for the length references and the 3-4 rivet is appropriate and called out for in the plans, yet getting the rivets to set properly continues to be an issue. Suggestions while I wait for the new parts? Up to this point, I haven't had a problem with setting rivets with the squeezer, all of a sudden I'm batting .100.

[TASEsq]

Hi,

I don't know if it is related, but i had issues on my VS where at least half of the spar to skin rivets bent over. I found it was that the nuts on the pneumatic squeezer yoke were a little loose, and the yoke itself was rocking a little.

Once i tightened all the nuts properly, i had no further issues.

Cleveland sells some 'quick release' pins - i had these for a while on the tool, but it results in the same thing (rocking yoke). The bolts and nuts down up tight helped to get straight rivets.

[Brantel]

I have just finished my elevator trim tabs over the past several sessions. You can check my blog for pics but I used a pneumatic squeezer and two different yokes for the entire assembly of them.

I used the longeron yoke for the trim tab control horns. I put the rivets in aft of the spar first before clecoing in the spar. Then I did the spar. I used a small diameter set on the squeezer ram and turned my quick release pins out of the way to get close to the trim tab control horns. Worked great but I was very careful to align and check for clearance during the squeeze. For the spar, I slid the yoke in from the side because there was not enough clearance to just place it over the spar.

For the hinges, I used a different regular yoke that has been modified by grinding some of the top tip away for clearance. I did this way back when I built my RV-7. Pics of it on my blog. I used a set that was just thick enough to provide clearance for the hinge eyelets. Be careful to plan for the fact that the rivet gets squeezed and the yoke will come close to the eyelet. Also be sure you don't squeeze with the sets too close to the eyelet as they may bend the eyelet out of position or break it off.

As for the hinge rivets, I remember when building my 7 that the advice was to never fully set rivets that are attaching a soft hinge. The hinge is so soft that it will get damaged by the riveting process and it does not provide good backup for the rivet tail which can lead to tipped rivets. What I did for my 7 and what I did for these 10 tabs is to squeeze those about 80% of normal.

For bending the closeout tabs, I did not use any tape. I just clamped the wedge blocks in nice and tight and after starting the bend by hand, I used a small smooth faced hammer and tapped ever so lightly about a thousand times to bend the tab over. Worked like a dream. A thousand tiny taps is better than fewer heavy ones. I don't use the rivet gun method per the directions. The hammer is much more controllable.

[Thunderpig]

Oddly, enough...I have been pouring over your blog! Thanks for the reply...going to spend my post Christmas time trying to finish these up...right after I final drill the tail cone...