Tank attach angle problem?

[skatetrainer]

I purchased a kit with a completed wing. While fabricating the other tank attach angle (the one that has two contoured edges) I realized that the completed wing tank has a "square" tank attach angle that was not cut down to the one inch radius. It looks kind of funky. The one edge was contoured to the tank rib face. The other edge is not. I looked at the completed wing because I was wondering how accurately I need to get this bracket set square to the rib and set at the correct position on the rib for mounting to the fuselage. So here's the questions: Am I going to have to radius the completed attach angle bracket or is the larger dimension OK? Is the positioning of the attach angle to the rib critical or is there adjustment potential in the attachment to the fuselage? I found the photo on Dan's site but he didn't mention any adjustment potential on the bracket that comes from the fuselage. http://www.rvproject.com/20031220.html

BTW - I'm thankful this year for having my medical in order to fly.

 

[Pmerems]

I think you will be OK

The completed tanks bracket may not be carved the way the plans call out but if the upper and lower ends of the bracket don't' extend beyond the tank skins you don't have an issue.

As to the location and squareness to the wing, it is hard to judge without a photo. However the bracket that attaches to the fuselage is 4130 steel sheet metal and can be persuaded to adjust for angular mismatches.

I hope this helps.

Paul (RV-7A finishing kit)

 

[ditch]

I was wondering about these to. Made one tonight and just want to know if these are right before I drill the attach holes in them. Tried to make them as close to the drawing as I possible could. The one thing I noticed is that there isn't any room to buck the forward most rivets on the rib with them in place. Does the bracket get installed after the skin is riveted on? If someone that has done these already, and they work on the plane, could you let me know if they seem ok, I would appreciate it.

 

[morlino]

My build manual (3/2/06 revision, page 7-7 about 2/3rds of the way down) says to rivet the rib to the skin first and then rivet the bracket to the rib. It confused me at first too, I had to re-read it many times before I found it.

As to the original question, I would not worry about it for now. The radius shown on the plans does not appear leave a lot of extra edge distance from the hole that gets drilled in the T-405 when you attach the wing. I think it is on drawing 38. You are probably better off having too much of the bracket left as opposed to not enough. I think you'll have a chance to trim it when you are fitting the wings.

 

[Pmerems]

Another tip on riveting the end ribs-doubler plate

Gents,

When riveting the end ribs to the tanks there is a doubler plate the goes on the inside of the rib. I fabricated mine and riveted them in place (outboard rib) before riveting the rib to the skin. I did this because it is much easier to rivet the double on the rib as a stand alone assembly. I had about 1/16 gap between the doubler leading edge profile and inside of the leading edge of the skin.

Now for the bad part.

After carefully riveting the outboard ribs in position with ProSeal I cleaned up the excess ProSeal on the skin and found that during the riveting near the double the skin flexed enough to actually dent the skin where the doubler lies beneath (happened on both tanks). It isn't too bad just another frustrating accident that could have been avoided. Fortunately the dents are on the bottom of the tank.

Moral:

If I were to do it again I wouldn't rivet the doubler in place until after the outboard rib is riveted to the tank skin.

Paul (RV-7A Finishing Kit)

 

[ditch]

Ya, thats what the directions say to do, now that I went and read ahead far enough. I usually don't read to far ahead. Might get scared of what lies ahead After putting my attach angle in place as close as possible to what the plans show, I wouldn't have any room to buck any of the rivets in the skin. Any body want to shed some light on how the angle attaches to the fuselage? Is there plenty room for adjustment or is the placement of the angle really critical? Thats the only thing I wonder about. If my placement is going to be correct.

 

[morlino]

I was able to get the bracket in the position that the plans call for. There was some interference, where the shop heads from the leading edge rivets and the attach bracket both tried to occupy the same space. I used a small round file to make some grooves/notches in the bracket to allow room for the shop heads.