Possible Error on Page 9-12

The trim pushrod is specified to be riveted with AN426AD3-3.5 These rivets seem really undersized. I used a 4.5 and it fit perfectly. Also, note that I did prime these parts so it could just be primer. The primer is pretty thin.

Both sides of that push rod are countersunk for double-flush riveting. I can't remember if I up-sized those or not. I sometimes find it difficult to judge rivet lengths required for those double flush.
Hopefully someone else will have a better answer.

I just completed mine this evening. I had the same issue. The -3.5 rivets looked way to short for double flush riveting of these parts. I went with -4.5's and it came out perfect.

3.5 is absolutely too short!

My theory is Van's is slowly trying to get us to think on our own... Or they are just a bunch of guys doing their best. I just squeezed four AN426AD3-4.5 rivets and they perfectly filled the countersunk holes. Thank you guys very much!

PS Be careful countersinking the rivet closest to the servo... I ended up using the counter sink without a cage. The same one you modified for the trailing edge of the rudder and elevators.

Dave (I don't have a signature) Beemer

Any deviations should be verified with Van’s.

As mentioned in section 5, regarding TE double-flush riveting, the shop head will not fill the countersink.

The 3.5 rivets for the trim pushrod are enough to keep the three pieces together. Plus, the pushrod is further kept together by the attach points on the ends to the servo and horn.

The problem I see with longer rivets is that you are potentially over-sizing holes that are already very near the edge of the part, and the material around the rivets is being deformed more than it should.

I am not a AE. Just my 2c.

I tend to agree...

The 3-3.5 called out is absolutely too short if you primed the parts. The 3-4.5 that I used was awesome and I feel fine because of the location on these rivets. Would not do this in many places without Van's giving the noncommittal build on.

So my conclusion?

Compromise with a 3-4 and build on?

PS The 3-4.5 really looks good but the question on structural integrity may be an issue. Remember a bad rivet is 90% effective (think about that before you drill out a bad rivet).

Reply from Van's support in 2022

Just to add, Vans tech support (Tony Kirk) answered my question on this back in September of 2022, that "The 3.5 rivets expand sufficiently to lock the parts together, 4.5's are not required"

I had asked about this and other threads with longer rivets. Just wanted others to know what Van's told me. I kept my 3.5 in there.