All
I must explain what we did on Bob's SX.
The vent is built and installed in the top of the tank per the instructions.
The vent tubing is rerouted to the top of the fill tube ( urethane molding
in the SX) where it is connected to a barb fitted to the side wall of the
fill tube. Next to this barb is another barb that has a vent tub to a
standard Europa SS bent vent tube with the standard holes in the back side
of the curve. The thing that is different here is it is mounted on the belly
just aft of the tank drains.
In this location it is out of sight, out of the rain (we live in Seattle)
and best of all can't spit fuel on the plane. The fill tube acts as an air
brake for the vent line and puts the spitting fuel back in the tank. If the
plane were to go inverted (God forbid) the vent will be high above the tank
and prevent full spill.
We fill from Gas cans and can pour as fast as we want. It works very well.
Sorry, I can't find a JPG of it on Bob's web page. It was such a logical
modification, I guess we did not think of it as notable.
Cliff Shaw
-----Original Message-----
From: owner-europa@aztec.houxou.com
Subject: Re: Fuel Tank Vent
Graham -- if you're referring to my check valve, ooops, I wasn't
clear. It's in the stub of the T-fitting, so the line is always
open. Tape over the vent simulating a clog, and even a slight vacuum
unseats it.
I wonder if the slow fill is not that the line can't handle the volume
of air required at typical filling rate, but the fact that with some
fuel in it near the tank whilst refueling means pressure in the tank
has to vent via tiny bubbles. What's relationship of volume of
a bubble to its diameter? Is greater relative surface tension in the
narrow tubing a factor also?
Regards,
Fred F., A063
Graham Singleton wrote:
>
> Two questions in my jumbled mind.
>
> 1 There will be a need for air to flow out of the tank as it all warms up
> on a hot day.
>
> 2 The reason it takes so long to fill Europas is the slow flow of air
> through the vent line. Ours was on the fin too, so it was longer than the
> standard, therefore even slower.
>
> Graham
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