Sequence of backriveting rudder stiffeners

[skyyking56]

Does anyone see a problem with not back riveting the rudder stiffeners on in the sequence the plans call for?
I would like to prep all of the parts for priming at the same time instead of back riveting them on now. I'm priming the rivet lines on the inside, so it would be easier to do all at once.
Since all of the holes are prepunched, I dont think this would affect hole alignment...or would it?????? All dimples would be upward...so that wouldnt matter.
Is there something that I'm not seeing here?
Appreciate any comments.

Jim King
7A Rudder (reading and re-reading the section on rudder becasue of all of the issues I see out there)

 

[andrew phillips]

I don't think it would make any difference at all. After you prep the skins and stiffeners you can build the frame components, then the entire rudder, then take everything apart, prep and prime all and assemble the skins/stiffeners first as you are doing the final assembly. Just be careful with the rudder skins w/o stiffeners on them because they could bend or kink (they are thin!). Also when back riveting the stiffeners be **** sure you don't run your rivet gun off the bucking bar or you will dent the skins (don't ask me how I know). Its real easy to do because you get into a rythem of riveting and the next thing you know you've gone too far!

Andrew Phillips
RV-7A Sitting here waiting for the truck today w/ QB fuse/wings/finish/firewall fwd

 

[jcoloccia]

The only problem is the rudder skins are so thin they will be very difficult to assemble with the rest of the airframe. There's also a chance that they will sag and while drilling and you won't get a nice tight rudder frame (although I think this is probably not a problem). Also, the chances of damaging the skin while working on it go up dramatically without the stiffeners in place.

At a minimum I would think you'd want to cleco the stiffeners on. Maybe I'm just not thinking about this right...I haven't had my cofee yet so anything is possible.

 

[GAHco]

Rudder Skins & Stiifeners

I would put them on as soon as your happy with your priming situation, it will make things come out better in the long run. How much?, who knows. That would depend on how careful you would be handling the skins without the stiffeners in place.

I can tell you one thing from personal experience.

If you don't have the big flat steel backup plate that Avery sells specifically for back riveting, get one now.

I set similar thickness plywood around it and then set the skins on top.
It made life easy, and my work look good.
I used it all I could on the control surfaces, and it made a huge difference.

I cant imaging using a bucking bar on these, even a larger one.

 

[Pirkka]

The stiffeners doesn't stiff rudder much for the direction it is most vulnerable when working with it. I clecoed my stiffeners and did everything as they would been riveted. Now I have all the rudder parts waiting for priming and riveting. Actually I ordered new R-710 because I didn't like how it come when done per plans so I still have something to fit there... Just work carefully as it is so **** thin stuff!

Search for "R-710" to avoid problems with rudder...

 

[skyyking56]

Thanks everyone.....I'm going to proceed without riveting on the stiffeners( i've allready predrilled them) and drilling everything else to final size being very careful with the fragile skin....then priming everything at once..

On the R-710 rudder horn brace I used the aft flange mounting face (to bottom of R-704 bottom rib) as a reference plane and just offset that down on the horn (probably 1/16" to 3/32" roughly) to what I thought would clear the radius on the inside of the R-704 and cut my line....
This cut ended up about 1/16" more material than the plans and I have slightly more than 2X edge distance...but I'm going to squeeze 3/32" rivets using my longeron yoke after the suggestion from Dan the man and Roberta. (I checked it out and they are completely right that it is possible)
I think the edge distance problem some people are having is using the "optional" 1/8" rivets...using the 1/8" rivets i could see a problem with the 1/4" edge distance. I think the plans could note something about that in the optional note using the 1/8 rivets to accomodate more edge distance.
Thanks again everyone,
Jim