Rivet Ribs to Spar... why now?

[RV7Factory]

As you could probably guess from the title, I am at the point where the directions say to rivet the aft wing ribs to the f & r spars. My question is simple... why rivet now, why not cleco and rivet later?

I mean, you are then going to cleco on the skins and match drill. It seems to me that if the ribs/spars are riveted you will be dimpling multiple layers, such as the spar & rib flanges (tabs) at the same time, which tends to distort parts. Seems like it would be better if you could deal with these individually.

I guess this allows you to put the wings in the jig and leave them there. Anyway, not trying to make an issue of this... I am just curious if there is something I am missing.

 

[f1rocket]

I always preferred to have the ribs permanently mounted so I knew they would line up well with the holes once I riveted the skin to the ribs. There's always a little bit of play involved with clecoed parts that might result in a skin ripple. Also, in the case of skins going over rib/spar joints, I don't try to dimple the two parts. Instead, I countersink the part underneath the skin and dimple the skin. This generally results in a smoother look.

 

[Kahuna]

Dont need to

You dont need to and I wouldn't. I found the dimpling much easier with the ribs in my hand passing through my pneumatic or hand squeezer mounted in a vice than up on the stand.

As a rule, dont rivet until you have no choice but to do it to move fwd.

Good luck,

 

[Capflyer]

Rivet Now

Rivet them now so they are firmly in place when you hang the structure in the jig. Be sure to rivet the rear spar to ribs first so it is easier to move them when riveting to the main spar. I think that clecoing them together then attempting to get everything just right in the jig will only bring trouble as the clecoes are just not as acurate as a firm rivet, plus it will be a whole lot more work. Dimpling the ribs while attached to the spars and hanging was a piece of cake. The holes match up anyways so why worry.

Mike R.

 

[RV7Factory]

Thanks for the advice guys... I appreciate it! Just to be clear, dimpling the ribs and rear spar doesn't seem difficult (while in the jig) , I just thought it was odd that Van's would have you dimpling the two layers at once, where the spar flange overlaps the rib flange. Probably not a big deal, just odd.

Be sure to rivet the rear spar to ribs first so it is easier to move them when riveting to the main spar.

Cap, I am confused (doesn't take much) I thought the general consensus was NOT to rivet the rear spar to ribs first so you can flex the ribs out of the way to rivet them to the front spar. I am not sure I follow you, could you please clarify this for me? Thanks.

Thanks again!!!

 

[Capflyer]

I thought the general consensus was NOT to rivet the rear spar to ribs first so you can flex the ribs out of the way to rivet them to the front spar. I am not sure I follow you, could you please clarify this for me? Thanks.

Ooops...
Your correct, do the main spars to ribs first, then the rear spar. I had it backwards, although I had it right when I riveted them. Sorry for my confusion.

 

[alpinelakespilot2000]

Cap, I am confused (doesn't take much) I thought the general consensus was NOT to rivet the rear spar to ribs first so you can flex the ribs out of the way to rivet them to the front spar. I am not sure I follow you, could you please clarify this for me? Thanks.

Thanks again!!!

Brad--I highly agree with your logic here. In my opinion, rivet the ribs to the main spar first. Those are the rivets you are going to be sweating over so you don't want anything in the way complicating those. I also highly recommend using Avery's Snap Socs over your rivet set. While masking tape works pretty good, the Snap Socs work better at keeping the double offset rivet set squarely on the head of the rivet. Using them I did not have to drill out a single rib-main spar rivet (and I bucked them all myself too).

On the other issue, I also highly recommend following Van's directions and riveting ribs to spar before fitting skins. Dimplng with your hand squeezer is really not that hard. Moreover, relatively speaking, there's a lot of weight on the ribs when the entire skeleton is clecoed together that the clecoes may not do as good a job of holding. As mentioned above, this could induce a certain amount of slack in your wingskins once you go to rivet the skins on. Probably not much, but why chance it? Just my opinion.

Finally, if the -7 rear spar rivet call-outs are anything like the -9, they may be a little long where the rear spar and rear spar doubler plates overlap, so check them before squeezing. I had a few fold over until I realized I needed to grind a little bit off the rivets called out for in the drawings.

Other than this, I followed Van's instructions on the entire skeleton and had no problems whatsoever. Now the leading edges and fuel tanks are a different story....

 

[rzbill]

Wing Jig and support jack

Brad,
Since you are at the rear rib stage, you will be hanging the wing skeleton soon. The instructions direct you to use a homemade jack of some sort to take the sag out of the skeleton assembly. That is all fine. However there was a little tweak required for my skeletons. Maybe yours too. Mine did not respond perfectly to a jack in the center of the span as shown on drawing 12A. With the jack in the center and extended per directions, the spar had a mild (about a #40 peak to peak) "s" curve with the ends and center OK but the outboard spar section curved above target and inboard spar section curved below target. I had to move the jack support point about 2 ribs towards the wing root in order to get all the main spar holes to line up with the gage string. I think it is due to the varying geometry (stiffness) of the main spar.