Wendell Voto wrote:

> I find it interesting that you get water in the sump on a Velocity. A
> previous owner of one told me that since the tanks are
> composite/sandwich structure that water does not condense in the tanks
> and never got any moisture in the fuel.  Where are you getting fuel?
> Could it have water in it? (they put water in everything now days to
> "enhance it" or make you pay $4 a pound for it).
> Wendell


Please, everyone, please understand that ANY closed tank with a small
orifice opening (a vented fuel tank, for example) can become a very
effective water pump.  The process:

-You spend Saturday flying, and park the plane on the ramp in
anticipation of Sunday's flight.  The hot sun keeps the fuel in the half
full tank warm for the rest of the evening.
-As the sun sets, your tanks begin to cool.  Cool gasses occupy less
volume, tank sucks air in through the vent (exactly as it was designed
to do).  Unfortunately, it's sucking air at exactly the same time as
water is dropping out of the air mixture.  This may be more of a problem
in North Carolina than other locals, but evenings here can be downright
sticky in the summer.  The air that the tank is sucking will be VERY wet.
-When the tank warms in the morning, the gases will expand and it will
push out the air above the fluid.  The water that was in the air is now
below the fuel, so it doesn't get pushed out.
-You can't make it to the airport Sunday, so the plane sits on the ramp
all week.  Each day, the tank will heat and cool, sucking in a gulp of
wet air every night.

The end result is a pumping action.  A very insidious and unavoidable
one.  It doesn't matter what they tank is made of.  A full day's heat
soak, followed by a full night's cooling will make the pump work.  The
only way to stop is to:
1)Live in a place without water vapor problems.  Either a very dry
environment, or one so cold that all the water sits frozen on the ground.
2)Seal the tank perfectly completely.  At which point it won't work well
as a vehicular fuel tank, but at least won't have to worry about water
in the fuel.

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