Tank Rivet Question

[WingsOnWheels]

The plans specify AN426AD3-3.5 rivets for the baffle-to-rib rivets on the end ribs of the tank. I can't think of any reason these need to be flush, I don't see any interference issues here. Am I missing something? Is there any reason not to use 470AD4-X rivets here rather than the -3s?

If 426 rivets are required, what side should be flush?

Thanks,

 

[WenEng]

Isn't it the nesting of the dimples....

in the baffle and rib end flange that adds some measure of additional strength and rigidity to the tank structure?? Just a guess.. However, I have seen some who countersink the tank skin and elect not to dimple the long runs on the rear baffle for ease of installation. I dimpled mine and used the 426s.

 

[WingsOnWheels]

in the baffle and rib end flange that adds some measure of additional strength and rigidity to the tank structure?? Just a guess.. However, I have seen some who countersink the tank skin and elect not to dimple the long runs on the rear baffle for ease of installation. I dimpled mine and used the 426s.

That makes sense, but it is only the end ribs that use flush rivets. Maybe the dimples provide additional sealing area for those end ribs.

Thanks,