"Dan Luke" wrote in message
...

"Roger" wrote:
Which is an old wives tale. The amount of water contained in 20-30
gallons of air is insignificant.

Just let those tanks inhale and exhale a few times. They do that
every morning and night so there is a *lot* more than 20-30 gallons
involved.

Another OWT, I'm afraid. Can you produce calculations to show how many
air exchanges/week occur in a half-full 40-gal. tank given a daily
temperature swing of 20 deg. F?

[snip]

I fly a Deb with about the same fuel capacity (not counting the tip
tanks). With half tanks and the plane hangered for two weeks in the
Spring, I drained over two full samplers of water out of one tank and
a half out of the other. None out of the auxiliaries as they were
full.

Since you bring up anecdotal evidence, I'll chip in: I've been parking my
airplane under a shelter within a mile of Mobile Bay for five years. I
never top up the tanks after a flight. In that time, I don't recall ever
sumping a drop of water out of any of the drains. My tanks hold 32 gal.
usable each.

[snip]
--
Dan
C172RG at BFM


To add another data point, when I had a Turbo Lance parked outside at Santa
Monica I never sumped a drop of water either. Same thing at Minden NV when
it was outside there. Never a drop.

Mike
MU-2