wrote:

So, if you fill a balloon with water, it will fly? Amazing! Does NASA
know about this?

No, but all pilots know that, when humidity, the amount of water in the air
(had to add that in view of the ignorance being displayed here), increases,
the air gets less dense. The plane can carry less weight and takeoffs will
be longer. Less dense is, uh, lighter.

--
Roger Long

On Thu, 13 Nov 2008 06:34:37 -0500, wrote:

EMPTY tanks dont magically fill up with water because of a mysterious
'condensation process'. :-)

Oh, but they DO. Any variation in temperature of the air surrounding
the tank will cause a pumping action. Temp goes up, the air in the
tank expands and finds a way out to create equilibrium. Temp goes
down, the tank inhales air containing moisture.

In dry weather, the tank will breath dry air, and evaporate any water
that is there. Unless the tank is NOT empty and the fuel layer
prevents evaporation of the water. A teaspoon full is all it takes.

Unless of course you think your tank is completely pressure sealed, of
course.

why do the fuel caps on cars hiss at you when you open them, if they
are not sealed?

Casady

On Wed, 12 Nov 2008 16:45:06 -0800 (PST), RichH
wrote:

EMPTY tanks dont magically fill up with water because of a mysterious
'condensation process'. :-)

There is a simple explanation. In a half full tank, the fuel will
overlie the water and keep it from evaporating, when it warms up
during the day.

Casady

On Wed, 12 Nov 2008 16:45:06 -0800 (PST), RichH
wrote:

Common knowledge is entirely faulty.

Fuel oil when manufactured (cracked, etc.) is rendered essentially
'dry'. Water (vapor in the air) 'equilibrates' eventually until the
oil is saturated with water from the atmosphere ..... and only after
the oil is SATURATED with water does the 'condensation' become
apparent. Simple speak: if your fuel is condensing water it means
that its laid around with an open vent too long and its now LOADED
with water.

How much is "LOADED" in ppm?


The BEST is to totally empty the tank for the winter, take home the
fuel and burn it in your heater.
EMPTY tanks dont magically fill up with water because of a mysterious
'condensation process'. :-)

50 ppm @20C ( 1ml / 20 litres)
fig.1 p11
http://www.journeytoforever.org/biof...bdgerpen96.pdf
Beware of biodiesel in boats..

On 2008-11-13 14:10:50 -0500, Goofball_star_dot_etal
said:

http://www.journeytoforever.org/biof...bdgerpen96.pdf
Beware of biodiesel in boats..

Oh, be *very* aware.....
/sarcasm

Only conclusion that means anything to auxiliaries is to add biocide,
which most of us overdo anyway.

High-volume users don't have to change a thing.

--
Jere Lull
Xan-à-Deux -- Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

On Thu, 13 Nov 2008 18:38:14 +0000, Goofball_star_dot_etal
wrote:

How much is "LOADED" in ppm?

Seventy ppm according to one reference to jet fuel. Enough for the
fungi and bacteria to get by. According to Flying magazine, if I
recall.

Casady

On Thu, 13 Nov 2008 21:13:46 GMT, (Richard
Casady) wrote:

On Thu, 13 Nov 2008 18:38:14 +0000, Goofball_star_dot_etal
wrote:

How much is "LOADED" in ppm?

Seventy ppm according to one reference to jet fuel. Enough for the
fungi and bacteria to get by. According to Flying magazine, if I
recall.

Casady

Nothing to shout about.. In Wales, at least.

On 2008-11-12 18:03:00 -0500, Marc Auslander
said:

Common knowledge is that we should top up our fuel tank for the winter
sleep. Argument is that otherwise the temp changes will continuously
condense water into the tank, as moist air is pulled in, condensed,
and then expelled.

I have no doubt that the effect is real, but wonder how big it
actually is. How much water per gallon (or liter) of air would
condense in one cycle of some plausible temperature range and some
plausible outside dew point?

(I think I know how to calculate this, but wonder if its already been done?)

I've seen an expert analysis by a surveyor fairly recently, but can't
find it now.

Essentially, he proved (at least to me) that the water isn't from
condensation but primarily from leaky fuel caps, both on the boat and
on the marina's tanks.

The volume of water than can be condensed out of the volume of air
contained in a fuel tank isn't significant, especially since air flow
in a typical tank is trivial.

--
Jere Lull
Xan-à-Deux -- Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

On Thu, 13 Nov 2008 02:09:13 GMT, Jere Lull wrote:

On 2008-11-12 18:03:00 -0500, Marc Auslander
said:

Common knowledge is that we should top up our fuel tank for the winter
sleep. Argument is that otherwise the temp changes will continuously
condense water into the tank, as moist air is pulled in, condensed,
and then expelled.

I have no doubt that the effect is real, but wonder how big it
actually is. How much water per gallon (or liter) of air would
condense in one cycle of some plausible temperature range and some
plausible outside dew point?

(I think I know how to calculate this, but wonder if its already been done?)

I've seen an expert analysis by a surveyor fairly recently, but can't
find it now.

Essentially, he proved (at least to me) that the water isn't from
condensation but primarily from leaky fuel caps, both on the boat and
on the marina's tanks.

The volume of water than can be condensed out of the volume of air
contained in a fuel tank isn't significant, especially since air flow
in a typical tank is trivial.

But the small amount of water that enters each time the surroundings
cool, stays there and accumulates. Over a 4 or 6 month layup?