Stopping a Tail Tank Drip

[jcarlyle]

Need some advice for stopping a drip (once per 20 seconds) from a tail
tank. I’m aware of using Vaseline / Chapstick / beeswax on under wing
dump valves, but what about on a tail tank? How would you even reach
it to goop it up (the seat is way up a 8 mm tube)?

The tank in question is a 5.5 liter slip-in tank on an LS8. It hadn’t
dripped at all until last weekend, when the temperature was around 5 C
(no worry about freezing, I was ridge running). I didn’t check the
tension on the cable, so maybe the problem will go away when
reasonable soaring weather returns.

Any thoughts would be appreciated.

-John

[Bruno[_2_]]

On Nov 24, 12:39*pm, jcarlyle > wrote:
> Need some advice for stopping a drip (once per 20 seconds) from a tail
> tank.

I'm in the same boat. I emptied out the tank and blew air up into the
line from the bottom and then filled it again and the drip was gone.
I head dirt/debris move around inside the tank and figure that was not
allowing the valve to close completely on my ASW-20B tail tank. That
said, anyone have any good idea how to clean out one of these tanks?
You might have the same problem.

Good luck.
Bruno - B4

[Richard[_9_]]

On Nov 24, 2:23*pm, Bruno > wrote:
> On Nov 24, 12:39*pm, jcarlyle > wrote:
>
> > Need some advice for stopping a drip (once per 20 seconds) from a tail
> > tank.
>
> I'm in the same boat. *I emptied out the tank and blew air up into the
> line from the bottom and then filled it again and the drip was gone.
> I head dirt/debris move around inside the tank and figure that was not
> allowing the valve to close completely on my ASW-20B tail tank. *That
> said, anyone have any good idea how to clean out one of these tanks?
> You might have the same problem.
>
> Good luck.
> Bruno - B4

Be careful blowhards blow up tanks,

Happy Thanksgiving

Richard.
www.craggyaero.com

[Martin Gregorie[_5_]]

On Wed, 24 Nov 2010 14:23:59 -0800, Bruno wrote:

> I'm in the same boat. I emptied out the tank and blew air up into the
> line from the bottom and then filled it again and the drip was gone. I
> head dirt/debris move around inside the tank and figure that was not
> allowing the valve to close completely on my ASW-20B tail tank. That
> said, anyone have any good idea how to clean out one of these tanks? You
> might have the same problem.
>
Have you guys seen the valve used in your tail tanks? Could the valve be
held open by slipping a thin plastic rod up the drain while you flush the
tank out?

Your local friendly RC model shop sells a rod that would probably do the
trick if the valve design is one that wouldn't be damaged by it: its the
core of the plastic Bowden Cables used to connect a servo to its control
surface. Its quite stiff and somewhere between 2 and 3 mm in diameter.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[T8]

On Nov 24, 5:23*pm, Bruno > wrote:
> On Nov 24, 12:39*pm, jcarlyle > wrote:
>
> > Need some advice for stopping a drip (once per 20 seconds) from a tail
> > tank.
>
> I'm in the same boat. *I emptied out the tank and blew air up into the
> line from the bottom and then filled it again and the drip was gone.
> I head dirt/debris move around inside the tank and figure that was not
> allowing the valve to close completely on my ASW-20B tail tank. *That
> said, anyone have any good idea how to clean out one of these tanks?
> You might have the same problem.
>
> Good luck.
> Bruno - B4

Depends what's in there. Step one: remove tank, inspect.

My 20B has a welded aluminum tank that required major work two years
ago to restore to service. New electric valve, some cutting &
welding. Cleaning, blasting, corrosion proofing and sealing with fuel
tank sealer. Works great since, no leaks.

-Evan Ludeman / T8

[jcarlyle]

Martin - keeping the valve open is easy, I just use the lever in the
cockpit. Filling pressure is limited to a 1 meter head, but maybe
filling and dumping repeatedly will clear out anything in there. The
funnel has a fine mesh, so it's hard to see how junk could have gotten
inside the tank.

Bruno, Evan - unlike your tanks, my tank is plastic, so no oxide
worries. Getting it out is a little involved, but the maintenance
manual has clear instructions. That's a last resort, though. Sounds
like you may have no options, though, Bruno.

I'll check the cable tension leading to the valve this weekend. If
it's tight in the closed position, I bet the drip is due to cold
weather.

Meanwhile, anyone have any ideas on how to apply Vaseline to a valve
seat located some distance up an 8 mm tube?

-John

[Bill Bullimore[_2_]]

>I'll check the cable tension leading to the valve this weekend. If
>it's tight in the closed position, I bet the drip is due to cold
>weather.
>
>Meanwhile, anyone have any ideas on how to apply Vaseline to a valve
>seat located some distance up an 8 mm tube?
>
>-John


Know any pilots who are gynecologists?

[Papa3]

On Nov 24, 9:47*pm, jcarlyle > wrote:
> Martin - keeping the valve open is easy, I just use the lever in the
> cockpit. Filling pressure is limited to a 1 meter head, but maybe
> filling and dumping repeatedly will clear out anything in there. The
> funnel has a fine mesh, so it's hard to see how junk could have gotten
> inside the tank.
>
> Bruno, Evan - unlike your tanks, my tank is plastic, so no oxide
> worries. Getting it out is a little involved, but the maintenance
> manual has clear instructions. That's a last resort, though. Sounds
> like you may have no options, though, Bruno.
>
> I'll check the cable tension leading to the valve this weekend. If
> it's tight in the closed position, I bet the drip is due to cold
> weather.
>
> Meanwhile, anyone have any ideas on how to apply Vaseline to a valve
> seat located some distance up an 8 mm tube?
>
> -John

Hi John,

I have the same problem and I believe we have the same exact tail
tank. My temporary solution involves a foam ear plug stuff into the
tail tube. Suprisingly, it stays put, yet the head from the tank is
enough to eject it when the valve is opened. Since I'm always within
the aft CG limit, there's no safety risk if it doesn't drain (except
for cold weather, and I fly dry when it's close to freezing). But,
I'm planning to pull the tank this winter and do a proper inspection
and adjustment/repair as needed.

P3

[jcarlyle]

Hi, Erik,

That's a very ingenious temporary solution! I would've never thought
of that trick.

Your glider and mine are pretty similar in age. I wonder if the drip
problem is something that strikes LS8s with the 5.5 liter tail tank
over a certain age. I think the LS6 used a similar tank - any LS6
owners experiencing something similar?

Good luck with the rework, Erik. If you think of it, take some
pictures of the valve to document the problem.

-John

On Nov 25, 10:28 am, Papa3 > wrote:
> Hi John,
>
> I have the same problem and I believe we have the same exact tail
> tank. My temporary solution involves a foam ear plug stuff into the
> tail tube. Suprisingly, it stays put, yet the head from the tank is
> enough to eject it when the valve is opened. Since I'm always within
> the aft CG limit, there's no safety risk if it doesn't drain (except
> for cold weather, and I fly dry when it's close to freezing). But,
> I'm planning to pull the tank this winter and do a proper inspection
> and adjustment/repair as needed.
>
> P3

[sisu1a]

> Your glider and mine are pretty similar in age. I wonder if the drip
> problem is something that strikes LS8s with the 5.5 liter tail tank
> over a certain age. I think the LS6 used a similar tank - any LS6
> owners experiencing something similar?

Is there anything that would be destroyed by putting a CLR solution in
the tank and letting it soak? By your and others descriptions my
guess is that there are water deposit/oxidation buildups preventing
the valve from being able to completely seat, which could be dissolved
with a CLR treatment. Among other materialsn it's list of materials
it's rated safe to use on is fiberglass, and there are even directions
for using it in coffee makers so it's not terribly caustic although it
is very effective at dissolving the stuff it was designed for -Calcium/
Lime/Rust.

-Paul

[Morgans[_2_]]

>>Meanwhile, anyone have any ideas on how to apply Vaseline to a valve
>>seat located some distance up an 8 mm tube?
>
> Know any pilots who are gynecologists?

How about a syringe thing that is used to give babies an oral dose of liquid
medication? Hot glue a small stir stick or small tube of some type, and it
should be able to get up there to the source.

I also might make a suggestion to use air tool O-ring grease. It is a long
chain grease that acts almost like it has long fibers in it. It should stay
around much longer than Vaseline.
--
Jim in NC

[jcarlyle]

Paul,

I'm not too comfortable with using CLR. It says not to use on plastic
laminates or Formica, and my tail tank is plastic. What I'm more
worried about is the valve. I suspect it's got rubber in it, and
there's nothing on the label that says CLR is safe for rubber. But
thanks for your idea.

I'm not convinced that the drip is due to crud build up. This drip
suddenly appeared, after a summer and fall with no problems. That's
why I have a suspicion that it may be due to an overly tight cable,
which contracted slightly more in the cold to cause the drip. I'll
check the cable tension this weekend to rule the cable in or out.

-John

On Nov 25, 3:15 pm, sisu1a > wrote:
> Is there anything that would be destroyed by putting a CLR solution in
> the tank and letting it soak? By your and others descriptions my
> guess is that there are water deposit/oxidation buildups preventing
> the valve from being able to completely seat, which could be dissolved
> with a CLR treatment. Among other materialsn it's list of materials
> it's rated safe to use on is fiberglass, and there are even directions
> for using it in coffee makers so it's not terribly caustic although it
> is very effective at dissolving the stuff it was designed for -Calcium/
> Lime/Rust.
>
> -Paul

[jcarlyle]

Jim,

I'm not familiar with the syringe you speak of. It would have to be
small in both diameter and length to work, as the tube is only 0.375
inches inside diameter and is probably 12 inches long (and turns 90
degrees, too). I was thinking more along the lines of a cut down Q-tip
bonded to the end of a wire.

I'm also not familiar with air tool O-ring grease. I'll talk to a
mechanic friend about getting some. Thanks for the idea.

-John

On Nov 25, 4:49 pm, "Morgans" > wrote:
> How about a syringe thing that is used to give babies an oral dose of liquid
> medication? Hot glue a small stir stick or small tube of some type, and it
> should be able to get up there to the source.
>
> I also might make a suggestion to use air tool O-ring grease. It is a long
> chain grease that acts almost like it has long fibers in it. It should stay
> around much longer than Vaseline.
> --
> Jim in NC

[Morgans[_2_]]

"jcarlyle" > wrote

> Jim,
>
> I'm not familiar with the syringe you speak of. It would have to be
> small in both diameter and length to work, as the tube is only 0.375
> inches inside diameter and is probably 12 inches long (and turns 90
> degrees, too). I was thinking more along the lines of a cut down Q-tip
> bonded to the end of a wire.
>
> I'm also not familiar with air tool O-ring grease. I'll talk to a
> mechanic friend about getting some. Thanks for the idea.

Go to the drug store, and ask for devices for giving a baby liquid medicine.
There probably are a few different things there hanging together for doing
that.

The syringe diameter is not important. The only thing being stuck into the
tube would be a small diameter tube stuck onto the syringe. Find something
for that, that is flexible enough to go up your tube. Fish tank air hose,
small engine gas line, medical IV tubing, medical tubing for oxygen, all
come to mind as possibilities.
--
Jim in NC

[jcarlyle]

I understand now. Thanks!

-John

On Nov 26, 8:51 am, "Morgans" > wrote:
> Go to the drug store, and ask for devices for giving a baby liquid medicine.
> There probably are a few different things there hanging together for doing
> that.
>
> The syringe diameter is not important. The only thing being stuck into the
> tube would be a small diameter tube stuck onto the syringe. Find something
> for that, that is flexible enough to go up your tube. Fish tank air hose,
> small engine gas line, medical IV tubing, medical tubing for oxygen, all
> come to mind as possibilities.
> --
> Jim in NC

[Morgans[_2_]]

"jcarlyle" > wrote

> I understand now. Thanks!

Welcome, and come back and tell us how it worked.
--
Jim in NC