H Joe

Thats very informative to read...well done! Looks like you have got a good setup their...I have only one question though...what happens to the air in the tank when the time comes to re-fuel? where does that pressure go?

As far as i see it the vent needs to be able to flow airpressure both ways ie. vent pressure for re-fuelling & to releive the vaccum created during flight!
And in a perfect world needs to not leak fuel.

How does one acheive that?...i would love to know

Regards Scot