Gas Theft Nashua (ASH)

"RST Engineering" wrote:

(a) You can go through the math all day long and still not explain why
I have drained the (hangared) 182 after a particularly humid day or
two and get a tablespoon or two of water in the quick drains.

I see: math is false and your charming story is proof. Very convincing.
I have one too: I've been keeping a 172RG with 62-gal. capacity tanks
outdoors in one of the most humid places in the U. S. for six years. I
never top the tanks unless I specifically need to for the next flight.
Only once in that time have I ever had water in a sample, and that was
due to a bad fuel cap gasket.

So, you've got your little story and I've got mine--so what? I'm the
one with the real numbers on his side.

(b) You cannot explain why "drain the sumps" is a daily check list
event for both fuel trucks AND airplanes.

Indeed I can: it is done to test for and drain *any* contaminants from
the tanks. Was that supposed to be hard?

(c) You cannot explain why CessBeePipMoo all have drains at the low
point of the fueling system. It would be a hell of a lot cheaper not
to have to put them in there. Somebody somewhere thought it was a
good idea.

Indeed I can: they are there to enable testing for and draining of *any*
contaminants from the tanks. Was that supposed to be hard?

(d) You cannot explain why a hangared 150 from this airport fifteen
years ago dumped it into a pasture off the end of the runway and then
proceeded to drain two QUARTS (yes, that's quarts) of water from the
tanks.

You cannot explain why your anecdotes conflict with empirical knowledge
of the composition and behavior of the atmosphere. Come back when you
can.

--
Dan
C172RG at BFM

Dan Luke wrote:

"RST Engineering" wrote:


(a) You can go through the math all day long and still not explain why
I have drained the (hangared) 182 after a particularly humid day or
two and get a tablespoon or two of water in the quick drains.


I see: math is false and your charming story is proof. Very convincing.
I have one too: I've been keeping a 172RG with 62-gal. capacity tanks
outdoors in one of the most humid places in the U. S. for six years. I
never top the tanks unless I specifically need to for the next flight.
Only once in that time have I ever had water in a sample, and that was
due to a bad fuel cap gasket.

So, you've got your little story and I've got mine--so what? I'm the
one with the real numbers on his side.

My 182 was parked outside most of its life and we have fairly humid
summers here in upstate NY. I never found water in the fuel in 6 years
of owning the airplane. We used autogas and me and my partner both
tankered gas to the airplane and filled if before leaving, not after
returning. My partner had water problems before installing the flush
style gas caps, but none after that unless he pumped the water in while
fueling up. :-) I had a filter on my tank that also trapped water, but
he didn't and put some water in one time.

I think most water that gets to the drains comes in either through a
leaky gas cap or was pumped in with the gas. I don't think condensation
is a big issue. If it was, it would likely affect you more in flight
than on the ground as you climb up into cold air with humid warm air in
the tanks.


(d) You cannot explain why a hangared 150 from this airport fifteen
years ago dumped it into a pasture off the end of the runway and then
proceeded to drain two QUARTS (yes, that's quarts) of water from the
tanks.


You cannot explain why your anecdotes conflict with empirical knowledge
of the composition and behavior of the atmosphere. Come back when you
can.

Yes, I can't explain that for sure, but I'll bet it was from a leaky gas
cap, not from condensation. It would take years to suck enough air
through the vents and condense out the water to get two quarts.
However, with a leaky gas cap, this could happen in one or two
thunderstorms.


Matt

No, Dan, you do NOT have all the numbers on your side. Agreed, you can
calculate the amount of water in a saturated sample, but you cannot do the
simple calculations unless you factor in how many airchanges you get inside
of vented tanks in any given amount of time. I doubt sincerely that you can
even estimate, no less calculate, this factor.

Although if you can get me a government contract to study the issue, I'll be
happy to consider doing the consulting work {;-)

Jim



"Dan Luke" wrote in message
...

"RST Engineering" wrote:

(a) You can go through the math all day long and still not explain why I
have drained the (hangared) 182 after a particularly humid day or two and
get a tablespoon or two of water in the quick drains.

I see: math is false and your charming story is proof. Very convincing. I
have one too: I've been keeping a 172RG with 62-gal. capacity tanks
outdoors in one of the most humid places in the U. S. for six years. I
never top the tanks unless I specifically need to for the next flight.
Only once in that time have I ever had water in a sample, and that was due
to a bad fuel cap gasket.

"Dan Luke" wrote in message
...

"RST Engineering" wrote:

(a) You can go through the math all day long and still not explain why I
have drained the (hangared) 182 after a particularly humid day or two and
get a tablespoon or two of water in the quick drains.

I see: math is false and your charming story is proof. Very convincing. I
have one too: I've been keeping a 172RG with 62-gal. capacity tanks
outdoors in one of the most humid places in the U. S. for six years. I
never top the tanks unless I specifically need to for the next flight.
Only once in that time have I ever had water in a sample, and that was due
to a bad fuel cap gasket.

So, you've got your little story and I've got mine--so what? I'm the one
with the real numbers on his side.

No Dan, you do not have the numbers on your side. You totally forgot that
the air is not captive inside the fuel tanks. It is free to enter and exit
as the barometric pressure and local wind causes differences in pressure at
the fuel vents. So you may have part of the numbers on your side, you did
not correctly model the problem, and therefore your conclusions are probably
incorrect. Go back and do the problem correctly.

John Severyn
@KLVK

RST Engineering wrote:

(b) You cannot explain why "drain the sumps" is a daily check list event
for both fuel trucks AND airplanes.

(c) You cannot explain why CessBeePipMoo all have drains at the low point of
the fueling system. It would be a hell of a lot cheaper not to have to put
them in there. Somebody somewhere thought it was a good idea.

Aren't there other, more common reasons for sumping the fuel, such as
removing sediment, checking fuel type, and removing water that may have
been introduced via a contaminated fuel source?

Any of these problems could take an aircraft down, so the value of having
the sumps is much greater than simply removing water that may have
condensed within the cells/bladders/tanks from the surrounding humid air.


(d) You cannot explain why a hangared 150 from this airport fifteen years
ago dumped it into a pasture off the end of the runway and then proceeded to
drain two QUARTS (yes, that's quarts) of water from the tanks.

And you can attest to the fact that the accident aircraft was indeed
hangared this entire time, ruling out leaky (which is pretty common with
old 150s) or non-existent fuel caps, and that the water was not introduced
from an external contaminated source?

--
Peter

RST Engineering wrote:

(d) You cannot explain why a hangared 150 from this airport fifteen years
ago dumped it into a pasture off the end of the runway and then proceeded
to
drain two QUARTS (yes, that's quarts) of water from the tanks.

Sounds like good ol' pilot error to me. Somebody F'ed up and forgot to sump
the fuel system.

"RST Engineering" wrote in message
.. .
(a) You can go through the math all day long and still not explain why I
have drained the (hangared) 182 after a particularly humid day or two and
get a tablespoon or two of water in the quick drains.

Dan Luke calculated there could be 14 grams of water in 20 gallons of air.

1 tablespoon = 15 milliliters = 15 grams

(b) You cannot explain why "drain the sumps" is a daily check list event
for both fuel trucks AND airplanes.

(c) You cannot explain why CessBeePipMoo all have drains at the low point
of the fueling system. It would be a hell of a lot cheaper not to have to
put them in there. Somebody somewhere thought it was a good idea.

Water can enter tanks in ways other than condensation.

"Jon Woellhaf" wrote:

(a) You can go through the math all day long and still not explain
why I have drained the (hangared) 182 after a particularly humid day
or two and get a tablespoon or two of water in the quick drains.

Dan Luke calculated there could be 14 grams of water in 20 gallons of
air.

1 tablespoon = 15 milliliters = 15 grams

Yes. I also noted that that would be in extreme conditions. And even
if *all* that water condensed inside the tank (impossible: condensation
could not remove all the water from the air), not all of it would
necessarily enter the fuel; some would be in drops on the surfaces of
the tank that were not submerged in fuel.

(b) You cannot explain why "drain the sumps" is a daily check list
event for both fuel trucks AND airplanes.

(c) You cannot explain why CessBeePipMoo all have drains at the low
point of the fueling system. It would be a hell of a lot cheaper not
to have to put them in there. Somebody somewhere thought it was a
good idea.

Water can enter tanks in ways other than condensation.

Just so.

The condensation bugaboo is an old wives' tale. Perhaps, if an airplane
is parked for months with half-full tanks, a measurable amount of water
might accumulate due to heating/cooling respiration of the tanks, but it
might as easily be due to tiny leaks in the gas cap seals. I've never
found any in my airplane, which is parked two miles from Mobile Bay.

--
Dan
C172RG at BFM

(a) You can go through the math all day long and still not explain why I
have drained the (hangared) 182 after a particularly humid day or two and
get a tablespoon or two of water in the quick drains

I had the same problem after annual once. I called the A&P back and he
readjusted the cap. 5 years later, sitting outside, with never more
than 1/2 tanks, I haven't gotten even a drop of water in the tanks.

-Robert

I teach from a large fleet of Piper archers, arrows, and seminoles. We
never leave full tanks overnight, always "to the tabs", or "40 a side" in
the PA44. I've NEVER pulled water from the sumps UNLESS it rained (piper
caps leak, period). Even after a HEAVY dew, the only drops of water i've
sumped were the drops i saw drip in when i was visually checking the fuel
level (and yes i waited for them to sump out!). Have to agree that
condensation into fuel would contribute only mildly to water contamination.
Now then, fueling out away from home airport i've gotten "wet" fuel before,
but even that wasn't more then a pea sized bubble of water in the bottom of
the jar. Worst case i've ever seen was a particularly bad rainstorm in FL,
used a GATTS jar, it became a 50/50 mix of water/fuel, looked rather
spectacular. Kind of makes you wonder how much water gets into the system
when flying in a heavy rainstorm.....

That said... i NEVER even consider starting the engines unless i check fuel,
even if all i'm doing is taxiin the aircraft form one place to another,
don't want to pull a slug of water, contaminates, whatever INTO the fuel
lines for the next guy to get stuck with in the air (tho in THEORY it will
settle out into the gascolator/engine sump.)

"RST Engineering" wrote in message
.. .
(a) You can go through the math all day long and still not explain why I
have drained the (hangared) 182 after a particularly humid day or two and
get a tablespoon or two of water in the quick drains.

(b) You cannot explain why "drain the sumps" is a daily check list event
for both fuel trucks AND airplanes.

(c) You cannot explain why CessBeePipMoo all have drains at the low point
of the fueling system. It would be a hell of a lot cheaper not to have to
put them in there. Somebody somewhere thought it was a good idea.

(d) You cannot explain why a hangared 150 from this airport fifteen years
ago dumped it into a pasture off the end of the runway and then proceeded
to drain two QUARTS (yes, that's quarts) of water from the tanks.

Jim


"Dan Luke" wrote in message
...

"RST Engineering" wrote:

I would ten times over risk gas theft over water condensation overnight
in half-full or nearly empty tanks.

There's not enough water in 20 gallons of air to matter.

How much water is there? In *extremely* wet conditions (saturated air at
20 deg. C) there are only 14.7 g/kg of water in the air. A cubic foot of
air at SLP weighs about 34 grams at 20 C. 10 gallons is ~27 cu. ft., so
that gives about 900 g. of air and about 14 g. of water. Not a problem.

--
Dan
C172RG at BFM