Double Flush Rivets on Center Section Spar?

[RudiGreyling]

HI Guys,

I'm busy with the center section an noticed these callouts for double flush rivets. I assume some bracket will fit there in the future.

I'm thinking to countersink the spar flange 704 on the inside, then to countersink the middel skin F776 on the outside, and dimple the outer skin F772?

How did you guys achieve your double flush rivets here?

Thanks in advance,
Kind Regards
Rudi

 

[N57 OZ]

Lower skin to 704

Hi Rudi, I have just done this & you have to be real careful (either that or I am easily confused) The instructions talk about the specific case where skins overlap & the way to do this is mech countersink the outer skin so a 426 rivet is flush, this means you will slightly c/sink the skin under as well but apparently thats ok. In this case Vans suggest you double flush the rivets in case you ever convert from a tail to nosewheel. In this case the top of the 704 flange is mech c/sunk & the manufactured head goes in there, you then use a slightly convex rivet set on the underside of the fuse, very important to get the right rivet length.

hth
Stephen RV7 N570Z Reserved

 

[wingtime]

yup you got it

Rudi, your on the right track. I countersunk the outside of center section skin while it was in assembly with the center section. You have do it this way since the center section skin is .032 the countersink will go through the skin and into the 704 flange just a tad. The dimple of the forward bottom skin to nest into the center skin and spar.

Then when you have the forward fuse clecoed up you countersink the inside of the flange. This will work since the pilot of the countersink will ride in the hole of the fwd skin. This is a tricky spot since the microstop will not fit in there. I simply put the countersink cutter into my right angle drill
(they are the same thread) and did it that way. VERY VERY carefully that is using a cordless drill.

 

[RudiGreyling]

Thanks guys, appreciate the quick response, now I can go back to and finish this center section. Kind Regards, Rudi

 

[Davepar]

I dimpled both skins and didn't bother with double flush rivets. Worked out fine. There's more space than Vans indicates. Get out the gear leg mounts and check it out for yourself.

Dave

 

[alpinelakespilot2000]

I dimpled both skins and didn't bother with double flush rivets. Worked out fine. There's more space than Vans indicates. Get out the gear leg mounts and check it out for yourself.
Dave

That's great to know, Dave, because I dimpled all of my fwd F904 flange (except for the 3-4 rivets shown on the bottom center skin) before realizing that I had to leave the ones on each end un-dimpled if I EVER wanted to convert to trigear in the future. Now, I can't imagine ever wanting a nosewheel , but it sounds like I have not completely ruled out a possible gear change should I ever "see the light!"