Firewall flange

[dwollen89]

Currently working on mounting the firewall to the fuselage on a 7A. I spent hours yesterday meticulously mocking it up, measuring and measuring…and measuring the 5/8 setback. I finally drilled the flanges to the side skin. All turned out well except for the one top hole (or bottom as it’s upside down of course). I tried everything, including hitting it with a hammer from behind to move it forward. No luck. The end result is the setback on that one hole on each side is about 11/16 and the hole violates the edge distance. Anyone else have similar result here? Wondering if I should add an extra hole/rivet or make a backer plate for those holes/rivets. Very frustrating.

 

[bjdecker]

Not worth worrying about. Debur, Dimple, Rivet and keep building.

 

[wirejock]

Agree, but I like to ask Vans so I have documentation in my builder log. It's stainless so the edge distance rule may be different.

 

[lr172]

That wouldn’t concern me, as it is one rivet in a part that has limited structural significance.

 

[mcgaughy]

Currently working on mounting the firewall to the fuselage on a 7A. I spent hours yesterday meticulously mocking it up, measuring and measuring…and measuring the 5/8 setback. I finally drilled the flanges to the side skin. All turned out well except for the one top hole (or bottom as it’s upside down of course). I tried everything, including hitting it with a hammer from behind to move it forward. No luck. The end result is the setback on that one hole on each side is about 11/16 and the hole violates the edge distance. Anyone else have similar result here? Wondering if I should add an extra hole/rivet or make a backer plate for those holes/rivets. Very frustrating.

I agree with what others have said. I added some sealant (thin film) when I riveted the firewall flange to help seal out any CO gases. The sealant, while not structural, will further strengthen and reduce chance of cracking. If you want, you could overlay a thin piece of angle / metal to provide edge distance ....sandwiching the firewall flange hole lacking edge distance in the middle. Probably not necessary and adds more work to the project.

 

[lr172]

I agree with what others have said. I added some sealant (thin film) when I riveted the firewall flange to help seal out any CO gases. The sealant, while not structural, will further strengthen and reduce chance of cracking. If you want, you could overlay a thin piece of angle / metal to provide edge distance ....sandwiching the firewall flange hole lacking edge distance in the middle. Probably not necessary and adds more work to the project.

In addition, those look like the holes for the piano hinge. This part will be sandwiched in the middle, further minizing any issues.

 

[dwollen89]

In addition, those look like the holes for the piano hinge. This part will be sandwiched in the middle, further minizing any issues.

I was wondering that. Wasn’t sure how high the hinge went. This would be the last rivet before the firewall bends forward.