flap/aileron attach brackets before top main skin?

I saw someone, somewhere recommend attaching the flap and aileron attach brackets to the rear spar before installing the top skin, with the idea that it was a lot easier to do the necessary drilling and riveting without the skin in place. Is this true of the -9's? Any suggestions? Go ahead? Wait?

(I'm waiting for my EAA tech counselor to come in 7-10 days befiore riveting on my leading edges and top skins but don't have much to do until then--I'd like to jump ahead a little).

Thanks,

Yeah, I can see how some might advocate that. However, I wouldn't. The whole top skin process is what really brings everything into alignment. I wouldn't assume the wing is done shifting (especially on the long -9 wings) until the majority of the top skin rivets lock it into place. I can just imagine if you riveted the flap and aileron brackets all on, then riveted the top skin, and things shifted just a bit. What a mess it would be. Those bracket rivets aren't that bad to do with the skin on. They just look scary. They would be a huge pain to drill out if alignment was sufficiently off.

I think it is a function of how lucky you feel

Just my 2c.

I think the brackets might get in the way when the top skins are riveted to the rear spars. Besides, it's the adjacent rib creating the clearance problem with the back end of your drill and rivet gun. Here's where your 6" and 12" #30 drills, 90 degree drill adapter and 1/8" offset rivet set get used and cussed.

Left wing done, doing outboard right top skin,
Steve

Thanks Scott and Steve, that was the kind of info. I needed. I think I'll just wait on the brackets and maybe start on the ailerons instead.

Steve

FWIW, the flap brackets are aligned by adjusting the center one, so I went ahead and riveted the two end flap brackets, leaving the center one until after the top skin was riveted. It enabled me to squeeze some 1/8" rivets instead of bucking them in a tight space. The brackets didn't cause any problems with riveting the top skins. At the very least you can rivet the inboard end one where all the holes are prepunched and access is worst. Of course, riveting the center flap bracket before the top skin would probably be a very bad idea.

Conor
RV-9A 90990 wings

I finished my flap brackets not long ago and I would agree that installing the end brackets first might be a good thing. Maybe just the rivets that would be hard to drive with the skin on. I waited until after the top skin was on and a few of the rivets were a problem but this is my first plane and first time using solid rivets. I forgot to align the center bracket with a string before riveting it and after I realized what I had done I checked and found that it was right on the money. Having the top skin on may have saved my bacon on that one.

Jim Wright RV-9A 90919 flaps Arkansas