Direction for riveting.

[Roy25101]

I think I'm going to get kicked off here for asking too many questions. Is there a sequence for riveting skins? I am about to back rivet the rudder skin to the stiffners and thought at one time I read a suggested sequence. I.e. Trailing edge to leading edge or every other one or from the center out. Thanks in advance.

[SgtZim]

You're safe Roy. I'd have been kicked out a long time ago for asking too many questions. Apparently we get a pretty big allowance.

Mine was done over a year ago and I keep stuffing more things in my brain - I think what I did was backrivet all the stiffeners to one side of the rudder first. I thought that was a little hard because I didn't want to "unbend" the pre bent trailing edge, but that turned out to not be a problem. I later made a couple of 90 degree brackets out of scrap 2 x 4 and shelf brackets - and used them to hold skins open for backriveting. Or you can use a helper to hold the skins wide enough to get the job done.

The other side, I would rivet the row of rivets closest to the bend first, starting in the center and working outward alternating as you go. Then advance to the next row and do the same - I like to try to keep the stresses even as possible.

I also forgot to add a glob of RTV or similar material at the trailing edges of the stiffeners as others have done. I think that was mentioned in the plans as well, to help prevent cracking - but if I have an issue I'll make new parts. I'm more concerned that even a little RTV will make it a bit harder to balance. Just don't fill them up with expanding foam! There was a post here just last week of a second owner finding his rudder full of the stuff. His plane did not fly well - he's lucky the thing didn't flutter and break off.

[KatieB]

I riveted mine from the center of each stiffener out to the trailing edge then to the leading edge. I doubt it makes much difference, but the thing NOT to do is run the rivet set off the edge of the backrivet plate!! I wrecked my first rudder skin that way.

There is no such thing as too many questions. Best to ask them now rather than AFTER you assume the wrong answer!

[Marc Bourget]

Few observations:

Sequence becomes more of an issue the older the rivet and thinner the skin(s).

Since the question applies to more than just the rudder mentioned, On some parts you have to worry about ways of "painting yourself into the proverbial corner"

On wing panels, one consideration would be to attach some 2' aluminum angles to the lower trailing edge. I would build mine straight, rather than with "washout" and it's easy to sight down the trailing edge as you proceed with riveting and watch how the wing "works" as you rivet. If it starts moving in directions not desired, you have a few friends apply counter-torque for a few rivets until it regains "straight" on it's own.

[rightrudder]

Originally Posted by KatieB

I riveted mine from the center of each stiffener out to the trailing edge then to the leading edge. I doubt it makes much difference, but the thing NOT to do is run the rivet set off the edge of the backrivet plate!! I wrecked my first rudder skin that way.

There is no such thing as too many questions. Best to ask them now rather than AFTER you assume the wrong answer!

I'm a member of the "Ran Out of Back Plate" too, even though I swore I wouldn't do it! Luckily, I got away with just a small crease that's hidden pretty well with checkerboard paint.

I found that tilting the rivet gun slightly toward the vertical edge of the stiffener resulted in better shop heads. I had to grind down the sliding plastic guard on the rivet set (imagine a "D" shape) to get the proper clearance.

Good luck!

[BillL]

DON'T RUN OFF THE BACKPLATE!!

Use a strong magnet to find and mark the end of the plate.

Yes, I did it too.