When to rivet lower fwd fuselage skin?

[sonex892.]

So all you guys who waited until your DAR inspection: You rigged the wings with all of the F10 & F09 parts (all the bits aft of the spar tunnel) just cleco'ed in place? You can't rivet in the tunnel until you rig the wings, and those F10 & F09 parts all connect to either the spar tunnel or the lower rear horizontal cross-member. They can't really be riveted into a stable configuration without the bottom skin in, right? As strong as a well-cleco'ed bunch of parts seem, I think things can still wiggle into a different alignment when you put weight or torque on a series of cleco'ed parts...

Thanks,

--Noel

Noel

You are correct the aft spar tunnel cant be riveted before the wings are rigged.

From memory, it was 7 years ago. I prepped all the lower section parts to deburred stage,including the floor panel before rigging the wings. I rigged the wings with only the forward sparbox and firewall riveted. The engine mount and wheels were installed. I didn't have the glareshield installed.

After that I riveted the aft sparbox, contols, seat brackets etc leaving the void forward of the spar box open.

To confirm things were all still lining up, I clecoed the floor in place a few times along the way. It never moved at any point. I would definitely recommend having the floor clecoed in place when squaring things and riveting the firewall and forward spar tunnel. Obviously the floor defines a lot.

Did you essentially stop fuselage work at F09 and work on the canopy, fuel, electrical, and engine pages; then return to finish off the lower fwd fuse afterwards?

Thanks,
--Noel

No. I rigged the wings first then did all that other stuff later.

If you are still worried? Just rivet it now.

Steve
Sonex 892
235hrs
2016 RAA Aus best kitbuilt and amateur built aircraft.

Here is a pic of the floor going on just hours before the inspection

[Bryan Cotton]

Noel,
I'm having flashbacks. I had the exact same concerns. Nothing beats that floor to hold alignment. There are a few things that help though:
1) the tank cover and panel - mine were clecoed in during the process.
2) the splice plates. The top ones are bolted in already. You could bolt the lower ones in if desired but I didn't.
3) the forward fuse structure has some stiffness even without the floor. It is riveted to the tailcone. Consider your loads are low and how hard is it to deform the fuselage if you try right now?
4) as Steve says you can sneak the floor on to convince yourself all is well.

My rigging came out great, and the floor still clecoes on easily.

[mike.smith]

So all you guys who waited until your DAR inspection: You rigged the wings with all of the F10 & F09 parts (all the bits aft of the spar tunnel) just cleco'ed in place? You can't rivet in the tunnel until you rig the wings, and those F10 & F09 parts all connect to either the spar tunnel or the lower rear horizontal cross-member. They can't really be riveted into a stable configuration without the bottom skin in, right? As strong as a well-cleco'ed bunch of parts seem, I think things can still wiggle into a different alignment when you put weight or torque on a series of cleco'ed parts... Did you essentially stop fuselage work at F09 and work on the canopy, fuel, electrical, and engine pages; then return to finish off the lower fwd fuse afterwards?

Thanks,

--Noel

Noel:
Here's one of the in between pages of my rigging process. You can look before and after this page to see more.
http://www.mykitlog.com/users/display_l ... 948&row=16

Think about what clecos are for: to hold everything in alignment. They work just as well as rivets. I never found that to be an issue.

[jowens]

Consider at least test fitting your rudder pedals before riveting the floor and firewall. My install required numerous tweaks to the phenolic blocks to allow free movement. The pedals moved freely outside the airplane but the rounding to allow for the rudder pedal welds is hard to predict. I didn't want to remove any more phenolic material than necessary. I also hope to complete the hydraulic toe brakes and lines with everything open. My plan is to rivet both floors just prior to DAR inspection.

[Concorde]

Did you guys install the fuel tank and riveted the glare shield before rigging the wings ?

[Bryan Cotton]

I did not. My fuel tank is still out and glareshield is clecoed in.

[Concorde]

Thanks Bryan. So did you rig the wings with both floor and the glare shield clecoed in place or you took one of them off for easy access.

[Rynoth]

I rigged mine without glareshield or floor installed.

http://www.rynoth.com/wordpress/waiex/2 ... g-rigging/

[Bryan Cotton]

I had my glareshield and instrument panel clecoed in, but the floor out. Having the floor out is the important part of access to the places you need to drill.
https://youtu.be/6wGUBuIGPXI

[Concorde]

I thought that we had to have the floor on for stability while rigging the wings . I wonder what Sonex recommends.
Thanks.