Pulled Rivets for Leading Edge-Wing Spar

I just sent a question into Van's on this issue but am hoping to get a response here so I can keep working this weekend...

I've heard a couple places (but can't remember where) where builders were told by Van's that it was OK to use LP4- rivets in lieu of solid rivets for the leading edge rib to main spar rivets were it was difficult to buck. Can anyone CONFIRM that this is true and that LP4-'s were OK to use, ACCORDING TO VANS? I've had it in mind that I would use CherryMax in a couple of places, but ran out.

Thanks,

You heard correct. It is permissible.

LE rib rivets

Dan Chekoway has it noted on his website - that's the only 'documentation' I could find (but it's good enough for me). I just put LP4's in all but the outboard rib of my right wing (first one built). I couldn't see the sense in grinding down an offset rivet set even for the rivets that could be bucked. Even getting in there with a rivet puller is tough. I used my old pop rivet puller that was ground down for use on the fuel tank Z brackets.

Dennis Glaeser
7A - Wings (obviously

Setting solid rivets in the spar web wasn't difficult. You need a shooting partner. A shooting partner is needed lots of places later on, so why not cultivate one now? I sanded a double offset rivet set on a disc sander until it fit close to the ribs- took two minutes and does not ruin the tool. Put a bit of duct tape over the rivet cup to prevent marks on the rivet head - that's SOP. I found it helpful to duct tape the rivet set and beehive spring together to prevent rotation of the rivet set. If the set rotates it will jump off of the rivet head and mar the spar web. The tape also prevents scratching of the rib by the spring. The gun operator must use two hands; one to hold the gun and the other to hold the set in place and prevent rotation. I bucked one handed by reaching through the holes in the leading edge ribs. The rivets are easily set by sound and feel. Wrap the bucking bar with duct tape to prevent marks. Inspect later with a mirror and light. I think this method is probably easier (and more satisfying) than trying to fit a pop rivet puller in between the ribs, although I didn't try that. My wife, sons, and a neighbor have all shot rivets for me. I always buck. Steve.

I have worried about this topic for over a month. Today I just finished riveting the first leading edge on my -9 and guess what, it wasn't that big a deal. I did have to talk my wife into bucking (first time I have been able to do that), and then later my son. On the -9, I found that I only needed an offset rivet set for the outboard rib one other rib. The rest I did with a straight set.

A must have is the largest bucking bar you can find that fits through the holes in the ribs. The weight of the bar is all that is needed to set the rivet, so one only has to hold it in place deep inside the LE. Wrap it in tape. The extra weight keeps the work from bouncing and subsequent cutting of the heads. I used a 4.5 lb bar that was 8 inches long, about 1.5" x 1.5" cross section with a 2.5" foot. By rotating the foot I could reach the most upper and lower rivets easily.

Find a bucking partner that has hands and arms small enough to go through the small spar holes, and up to the shoulder from the inboard rib.

Give it a shot. It was much easier than I had been expecting.

Here's the response Van's gave me. So I will use solid where I can without concern about messing it up, and will use pulled wherever there is any question.

Thanks for the responses.


My question:
>
>In general, for any of the other LE rib to spar rivets, are the
> pulled rivets like a CherryMax or LP4 OK if I think I will have too
> difficult of a time bucking a solid rivet?

Van's response:

"You can use LP4-3s or 4's for the ribs but where the .125 doubler is
you will have to use the -4s, the -3s will be slightly too short.
Generally, the appropriate length LP or Cherry rivet can be
substituted for the AN rivets.

Vans"

Leading Edge Attachment to Spar- Beware!

If you are using a new "bucking" partner for this step, make sure that you warn him/her not to get in the habit of setting the bucking bar down on the spar while waiting for the next rivet to be set up. I have heard that someone out there had a bucker set the bar down on the spar only to find out that there was no spar...he dropped it right through the lightning hole in the spar much to the aft spar's discomfort...