RV-3 firewall .062" angle counter bore ?

[Larry DeCamp]

When the .062 angle is counter bored for the #40 drill ( 3/32 rivet), the angle does not lay completely flat when clecoed to the dimpled SS firewall. If the counterbore is increased, the hole will get too big to fit the rivet.

Any suggestions how to make this a good outcome

 

[Ironflight]

Hmmm....not sure I'm going to be much help on that one Larry - it was over two years ago, and I don't recall a problem. Wait a minute - Louise did most of that, so I just might not know about it!

One thing we discovered well afterward though - we wish we'd held of on the stiffeners until we had installed the prop governor recess. If you're going to do one, it will require a different layout of the stiffeners. Probably too late if you've already dimpled.....

 

[David Paule]

How about a -4 oops rivet?

Dave

 

[danbenua]

My suggestion is to countersink the angles so that a 3/32"
rivet head sits just below the surface (maybe a few thousandths).
When you rivet the SS material to the angles you'll find that
it is quite ductile and adapts nicely to the recess in the aluminum.
Try a few and drill them out if you don't like the results. Once
you know what a proper countersink depth looks like, it is
easy to replicate this on all the other places that countersinking
is required.

- Dan Benua
Tech Counselor
Repeat Offender