[AX-O]

I am building the tanks for an RV-8. The left tank has a flop tube and the right has a conventional tube. I decided to close the lightening hole on the second tank rib (counting from inboard to outboard) and put a trap door on both tanks. But then I was thinking?? If I go out and do spins, all the fuel is going to end up flowing outboard placing tremendous stress on the most outboard rib of the tank. Has anyone put trap doors on all the ribs to try and minimize the fuel flow outboard during spins or any other maneuvers?

 

[dan]

Maybe it's just me, but I don't think the effect would be as dramatic as you imply.

Picture doing rolls with full fuel...lots of RV drivers do that all the time! I personally believe that the roll rate exceeds the spin rate in general, and any force on that outboard rib would be greater in the case of a roll than a spin. These fuel tanks haven't been bursting due to all of us RV drivers rolling the cr$p out of 'em!

So my 2 cents is KISS and don't overthink it.

Personally I wouldn't bother with ANY of the inverted/acro mods in my fuel tanks next time. It's just not worth the additional complexity and...more importantly imho...using "life limited" parts (those flop tube hoses).

I know it's hard to anticipate your average flying while you're building (been there), but try to be realistic about just how much truly negative G time you'll really spend. And how much spinning you'll really do as well!

 

[AX-O]

Thanks Dan! Simple it is.