Gas Theft Nashua (ASH)

[Hank Rausch]

Flew into Nashua last Sunday for business, topped off the tanks right
after setting down. When I came back from business on Thursday, found
the right tank down quite a bit. I was going crazy looking for the
leak and checking the drain for seepage, until the line guy pointed out
that he filled the tank back up exactly 5 gallons--which happens to be
the volume of a standard gas can. He said he'd seen it happen to
another plane on the line, both tanks down 5 gallons.

It was parked pretty much in front of the tower, but it is a low wing
parked in a line of high wings so I guess it made the easiest siphon
target.

I've never given any consideration to gas theft but I think in the
future I will top off right before taking off, as at least thirsty
tanks will make a less attractive target!

Hank Rausch
N9906T

[[email protected]]

"Hank Rausch" > wrote:

> Flew into Nashua last Sunday for business, topped off the tanks right
> after setting down. When I came back from business on Thursday, found
> the right tank down quite a bit. I was going crazy looking for the
> leak and checking the drain for seepage, until the line guy pointed out
> that he filled the tank back up exactly 5 gallons--which happens to be
> the volume of a standard gas can. He said he'd seen it happen to
> another plane on the line, both tanks down 5 gallons.
>
> It was parked pretty much in front of the tower, but it is a low wing
> parked in a line of high wings so I guess it made the easiest siphon
> target.
>
> I've never given any consideration to gas theft but I think in the
> future I will top off right before taking off, as at least thirsty
> tanks will make a less attractive target!

That has happened here in AZ, too. Acquaintance with a 421 was down *20*
gallons. It's a gaited airport, but it was at a tie-down near the
self-serve fuel station -- maybe somebody just got confused (har!).
Imagine seeing a twin, or any other airplane, and just helping yourself.
Unbelievable.

[RST Engineering]

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

Jim



"Hank Rausch" > wrote in message
oups.com...


> I've never given any consideration to gas theft but I think in the
> future I will top off right before taking off, as at least thirsty
> tanks will make a less attractive target!

[Robert M. Gary]

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

I have a Mooney so filling the tanks is a rare event (7 hours of gas is
way more than I need and I don't like pulling a yaht around with a
Corvette). I generally keep only about 10 gallons per side when parked.
I park outside and have yet to see any water in the 6 years I've had
the plane. Maybe the fact that a Mooney technically doesn't have fuel
"tanks" makes it different.

-Robert

[Dan Luke]

"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

[Dan Luke]

20 gallons is ~27 cu.
^^

[John Gaquin]

"Hank Rausch" > wrote in message
>
> I've never given any consideration to gas theft

After 102 years of powered flight, you'd think locking gas caps would be
available.

[john smith]

In article >,
"RST Engineering" > wrote:

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

But, if you fill it up, and they siphon it out, don't you still have the
same problem?

[john smith]

> > I've never given any consideration to gas theft

> After 102 years of powered flight, you'd think locking gas caps would be
> available.

If you hook up a tube to the fuel drain and the vent is working
properly, a locking cap won't make a difference.

[Flyingmonk]

>> I would ten times over risk gas theft over water condensation overnight in
>> half-full or nearly empty tanks.
>
>But, if you fill it up, and they siphon it out, don't you still have the
>same problem?

First thing that came to my mind as well when I read that.

The Monk

[RK Henry]

On 4 Feb 2006 06:48:10 -0800, "Hank Rausch"
> wrote:

>Flew into Nashua last Sunday for business, topped off the tanks right
>after setting down. When I came back from business on Thursday, found
>the right tank down quite a bit. I was going crazy looking for the
>leak and checking the drain for seepage, until the line guy pointed out
>that he filled the tank back up exactly 5 gallons--which happens to be
>the volume of a standard gas can. He said he'd seen it happen to
>another plane on the line, both tanks down 5 gallons.

If this kind of thievery is going on at the airport, I'd be more
concerned about my airplane and its components than gas in the tanks.
A radio is worth a lot more than 5 gallons of avgas.

And if no one is notices gas siphoning, are they similarly oblivious
to people stealing an airplane to use for some nefarious purpose?
Whatever happened to Airport Watch?

RK Henry

[Gary Drescher]

"john smith" > wrote in message
...
> In article >,
> "RST Engineering" > wrote:
>
>> I would ten times over risk gas theft over water condensation overnight
>> in
>> half-full or nearly empty tanks.
>
> But, if you fill it up, and they siphon it out, don't you still have the
> same problem?

Yes, but the siphoning is an unlikely event. If condensation were a serious
concern, you'd prefer to take a small chance of theft plus condensation
rather than defending against theft at the cost of a much greater chance of
condensation.

--Gary

[nrp]

>If you hook up a tube to the fuel drain and the vent is working
properly, a locking cap won't make a difference. <

You'd have to be pretty patient to drain a significant amount thru a
quickdrain.

[RST Engineering]

(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
>

[Jon Woellhaf]

I once hooked a tube to the gascolator drain tube of my 182 and drained five
gallons in a few minutes. I put vicegrips on the drain control to keep it
open.

[Dan Luke]

"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

[Peter R.]

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

[Jon Woellhaf]

"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.

[Michael Ware]

> 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.

[bsalai]

RK Henry wrote:

>
> If this kind of thievery is going on at the airport, I'd be more
> concerned about my airplane and its components than gas in the tanks.
> A radio is worth a lot more than 5 gallons of avgas.
>
Today, yes.

[Michael Ware]

> RK Henry wrote:
>
> >
> > If this kind of thievery is going on at the airport, I'd be more
> > concerned about my airplane and its components than gas in the tanks.
> > A radio is worth a lot more than 5 gallons of avgas.
> >
Unless you are flying, and it's the last 5 gallons :)

[Matt Whiting]

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

[Dan Luke]

"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

[NVArt]

Jon Woellhaf wrote:
I put vicegrips on the drain control to keep it
> open.

I'm not puttin' vicegrips on *my* quick drain!!!

Have a good day!!

[darthpup]

I have been flying for 30 years and did find excessive water in tanks
from condensation on two occasions.

[Robert M. Gary]

> (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

[Robert M. Gary]

> You'd have to be pretty patient to drain a significant amount thru a
> quickdrain.

As quick as they drain, the also unscrew, dumping the entire contents
of the tank on the arm of the person doing the unscrewing..
-Robert (who knows from personal experience)

[Peter R.]

Michael Ware > wrote:

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

The question is, how did the water get there?

--
Peter

[Morgans]

"darthpup" > wrote

>I have been flying for 30 years and did find excessive water in tanks
> from condensation on two occasions.

And you knew how the water got in the gas, how???
--
Jim in NC

[nooneimportant]

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
>>
>
>
>

[.Blueskies.]

"Matt Whiting" > wrote in message ...
> Dan Luke wrote:
> ..... 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.
>
>.....
> Matt

This has been my experience also, the water mostly comes in from the outside during refueling or a bad filler cap. The
issue with refueling right before a flight is that the water will be in suspension and needs a while to settle out to
the sumps. Is this water in suspension going to cause a problem?

[RST Engineering]

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.

[Matt Whiting]

RST Engineering wrote:
> 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.

True, but I'll bet it isn't enough to get two quarts of water into 150
tanks! :-)


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

Better to stick with the electrons and leave the H2O alone. :-)

Matt

[Dan Luke]

"RST Engineering" wrote:

> 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.

Actually, the tank respiration is fairly simple to calculate by knowing
the high temp.and the low temp and calculating the quantity that would
need to be added to maintain atmospheric pressure in the tank at the
lower temperature. You will find, I believe, that even in extreme
temperatures the air change would be fractional, even after many days.
Remember also that when the air is most humid, the daily high/low temp.
delta is smallest, thus limiting tank respiration when condensation
conditions are optimum.

Can you to supply any empirical evidence for your claims?

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

Another poster has mentioned an actual experiment by Cessna that failed
to produce any detectable water due to condensation in the tanks. If
anyone has a link to a description of this experiment, please post it.

--
Dan
C172RG at BFM

[J. Severyn]

"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

[Dan Luke]

"J. Severyn" wrote:
> 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.

I believe I adequately showed that the amount of water present in 20
gal. of air under extreme conditions is small, and that the amount that
would actually condense is smaller still. If you believe tank
respiration will substantially increase water condensed out of 20
gallons of air, why don't you provide calculations showing that?

--
Dan
C172RG at BFM

[J. Severyn]

"Dan Luke" > wrote in message
...
>
> "J. Severyn" wrote:
>> 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.
>
> I believe I adequately showed that the amount of water present in 20 gal.
> of air under extreme conditions is small, and that the amount that would
> actually condense is smaller still. If you believe tank respiration will
> substantially increase water condensed out of 20 gallons of air, why don't
> you provide calculations showing that?
>
> --
> Dan
> C172RG at BFM
>
OK. I'll use your own numbers and assume they are correct.

"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"

You did not provide adequate or even convincing evidence that model the
problem.

If the air in the tank is exchanged 10 times over a few weeks (not
unreasonable due to temperature, barometric pressure changes and local
wind), the amount of water starts adding up. The water droplets on the
inside surface will get caught in the fuel as they drip or slowly flow into
the fuel. They will flow to the bottom of the tank and not evaporate as they
are covered with fuel.

In windy conditions, the air can exchange many more than 10 times. Most
aircraft have several fuel vents and many high-wingers connect the top of
the tanks to assure fuel delivery. The multiple vents allow lots of air
exchange if the plane is tied down outside with differences in pressure at
the different vents due to placement and wind.

So let's use your numbers....times 100 or more. 1.4 Kg of water (or more)
is a significant amount.

John Severyn
@KLVK

[Dan Luke]

"J. Severyn" wrote:
>
> You did not provide adequate or even convincing evidence that model
> the problem.
>
> If the air in the tank is exchanged 10 times over a few weeks (not
> unreasonable due to temperature, barometric pressure changes and local
> wind),

"Not unreasonable?" That's what your argument is based on? What is
your criterion for "not unreasonable"?

> the amount of water starts adding up. The water droplets on the
> inside surface will get caught in the fuel as they drip or slowly flow
> into the fuel. They will flow to the bottom of the tank and not
> evaporate as they are covered with fuel.
>
> In windy conditions, the air can exchange many more than 10 times.

Do you have any empirical data on which you base this number or did you
just make it up?

> Most aircraft have several fuel vents and many high-wingers connect
> the top of the tanks to assure fuel delivery. The multiple vents
> allow lots of air exchange if the plane is tied down outside with
> differences in pressure at the different vents due to placement and
> wind.

That is true of my airplane and the three club airplanes with which I am
familiar. All these aircraft are parked outdoors next to a bay on the
Gulf Coast and subjected to continuously damp and frequently windy
conditions. None are routinely topped off after flight--in fact, club
rules proscribe the practice. Persistent presence of water in fuel
samples has not been a problem with any of these aircraft.

> So let's use your numbers....times 100 or more. 1.4 Kg of water (or
> more) is a significant amount.

Yes, it is. So where is it? Certainly not in the planes I take fuel
samples from.

We have had this discussion before, I believe. I am still waiting for
you to produce any convincing data to make fuel tank
respiration/condensation credible as a serious source of water
contamination in aircraft fuel.

--
Dan
C172RG at BFM

[John R]

Hank Rausch wrote:

> Flew into Nashua last Sunday for business, topped off the tanks right
> after setting down. When I came back from business on Thursday, found
> the right tank down quite a bit. I was going crazy looking for the
> leak and checking the drain for seepage, until the line guy pointed out
> that he filled the tank back up exactly 5 gallons--which happens to be
> the volume of a standard gas can. He said he'd seen it happen to
> another plane on the line, both tanks down 5 gallons.
>
> It was parked pretty much in front of the tower, but it is a low wing
> parked in a line of high wings so I guess it made the easiest siphon
> target.
>
> I've never given any consideration to gas theft but I think in the
> future I will top off right before taking off, as at least thirsty
> tanks will make a less attractive target!

Thanks for the warning! When we had avfuel theft problems, it was usually
gear head types obtaining their racing fuel for their riceboxes. :(

[Ron Natalie]

wrote:
> It's a gaited airport,

Does it move with a trot, cantor, or gallop?

[RST Engineering]

It moves with a cantor and keeps kosher.

{;-)


Jim

"Ron Natalie" > wrote in message
m...
> wrote:
>> It's a gaited airport,
>
> Does it move with a trot, cantor, or gallop?

[Montblack]

("RST Engineering" wrote)
> It moves with a cantor and keeps kosher.


Such a deal I can get for you ...in the 5th ...to show.


Montblack

[Cub Driver]

On Sat, 4 Feb 2006 11:59:40 -0800, "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.

It's been years since I've seen water from the Cub. Not since the
switch to 110LL, in fact. So my take is that the water used to come
from the gasoline.


-- all the best, Dan Ford

email: usenet AT danford DOT net

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