Tip: Leading edge rib to spar rivets: RV-7

I finished riveting the leading edge rib flanges to main spar last night. I am hoping these were some of the most difficult rivets that I will encounter. All rivets were set with the manufactured head on the rib flange side and bucked from the spar side, per recommended practice. This meant having the rivet gun inside the leading edge, which was quite a challenge. But as it turns out, it is possible. I used a 3X gun with an offset cupped set and wonder if it might be easier with the shorter 2X, but also found that the air hose attach fitting for the 3X lined up with the top lightening hole in the ribs so that was a help. Each bay took a different combination of how to run the air line in to the gun and how to get the gun into the bay and properly positioned. I was able to complete the inboard rib and the two most outboard ribs without help, but the other three required a helper on the bucking bar. My thin arms made this riveting from inside the bays possible because I was able to reach in through various lightening holes and the access hole to support the gun and activate the trigger. On the 2nd and 3rd inboard ribs the rivet heads were completely blind so I used a combination of feel and an inspection mirror to get the cupped set properly positioned on the rivet head. And once there I made sure it didn't move until my helper confirmed the rivet was fully set. I was really pleased with the results and all rivets came out well the first time around, which was great because I was really dreading the thought of having to drill one (or more) out.

Learning more every day!!

Bill Vinson
RV-7 Standard Build @ 224 hours

If there are no pictures, it didn't happen!

Seriously, congrats on your "sticktoitiveness" in getting this done with solid rivets. I was where you are now about a year ago, took one look at that job and ordered a bunch of MSP rivets of varying lengths...

Cherrymax

I went with Cherrymax, which worked well. There's no way I was going to try and drive them blind. Sounds like you did well indeed!

this is pretty tough!

This is a tough setup - I'm doing my RV-8 now. I just tried riveting from the spar side with a 3x gun and long double offset. I really don't like the results after doing two rivets - even after grinding down the outer edge of the set and polishing it - the rivet head, rib and spar face are taking damage and smilies and the shop side is leaning into the rib some - though I think I got enough expansion for a solid hold. What's that number for Cherrymax?

LP-4

SgtZim said:

This is a tough setup - I'm doing my RV-8 now. I just tried riveting from the spar side with a 3x gun and long double offset. I really don't like the results after doing two rivets - even after grinding down the outer edge of the set and polishing it - the rivet head, rib and spar face are taking damage and smilies and the shop side is leaning into the rib some - though I think I got enough expansion for a solid hold. What's that number for Cherrymax?

Click to expand...

Contact Vans to be certain. I asked and was given the approval to use LP4-3 and LP4-4 but mine is a 7a.

Leading edge ribe to spar rivets

SgtZim said:

This is a tough setup - I'm doing my RV-8 now. I just tried riveting from the spar side with a 3x gun and long double offset. I really don't like the results after doing two rivets - even after grinding down the outer edge of the set and polishing it - the rivet head, rib and spar face are taking damage and smilies and the shop side is leaning into the rib some - though I think I got enough expansion for a solid hold. What's that number for Cherrymax?

Click to expand...

Don't give up yet! I was never able to get good results with a double offset rivet set. For the leading edge ribs, I used a long (about 12") straight rivet set with a Snap-Soc cap. Here's one example:
http://www.browntool.com/Default.aspx?tabid=344&CategoryID=34&Level=a
Of course the rivet set is at a bit of an angle so the gun clears the ribs aft of the spar but this is OK as long as the rivet set doesn't contact the rib flange. I managed to get all the rivets set by myself. It helps to have skinny arms to go through the lightening holes. On the inboard forward ribs, I made a wooden bucking bar guide to help keep the bucking bar on the rivet. It would have been easier with a partner, but I managed without.

That's good to know Terry. I purchased the required number of LP4-3 and LP4-4's which arrived yesterday from Van's, however it is of course my preference to use solid rivets where possible. I purchased a 12" rivet set for doing the main ribs many months ago, so I think I'll take a crack at your angled method for the most inboard and outboard leading edge rib as they will be the easiest, then if I find things too difficult as I work my way in, I'll use the LP-4's on hand.
Tom.

I also did alone with bucking from the inside, using a flattened offset rivet set with snap-loc.

One thing I wish I did better was to make sure the leading edge rib flanges towards the spar was better seated as they had a tendency to lift a little when bucking from inside the leading edge.

I believe it can be achieved by having a slight outward bend of those flanges which would keep pressure towards the spar when clecoing the leading edge skin to the spar.