What comes out of this hole?

Deelee

Deelee

Pattern Altitude
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Deelee
Ok, round two in the help-me-identify-this-leaking-fluid series of posts. This is regarding the underbelly of our PA28R-200. 1969 vintage.

Today, was bored silly so went out to wash-wax-all the plane. Got ambitious and started cleaning the bottom from tail first to nose. Got about two feet forward of the baggage compartment and stopped because I am pretty sure I need a heavier duty degreaser (it aint' bad, but wash-wax-all ain't cutting through it).

While I was under there, I noticed a drop of oily substance coming out of these holes on the bottom of the fuselage. Stupid me again should have taken a pic before I wiped it off, but I did take pics of the holes where the fluid was emerging. It wasn't necessarily red like hydraulic fluid... but it wasn't necessarily tan like the fresh oil that is now in our engine. Kind of a light tan.

Anybody know what kind of fluid would drip from these holes?? They are on the aft end of the ridges that run fore and aft on the underside of the fuselage. Kind of like where the trailing edge of the wing would run as it goes into the fuselage. I have honestly not done much googling yet. Figured I would ask ya'll first (actually I'm gonna start googling in parallel here). Thanks!

The holes -

hole1.jpg

hole2.jpg

hole3.jpg
 
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oooh maybe. If that is some sort of a channel that runs fore to aft and terminates with that hole... then maybe...

Any ideas why the resulting liquid drop would by oily and ligh-tan?
 
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Doug Reid said:
Has anyone ever fogged corrosion x inside your fuselage
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ACF-50, I believe... have to check the logs. But I think that's what was done. We have only owned this since July...... aaandd just Googled a bit.... something about weeping???
 
Mine seeped hydraulic fluid (red) from there. Mechanic investigated and found no leaks; he thought there was a leak at one time and the oil is slowly finding its way out. In the Lance the auto retract and emergency extension valve are located right behind the main spar and any leaks would find their way down into there (longerons...is that the right term?); I think the Arrows are the same.
 
Jim K said:
Mine seeped hydraulic fluid (red) from there.
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Interesting... something maybe they can look at during annual later in March... But your guy didn't find any leaks??
 
There's some kind of glop that mechanics spray wherever they go that is said to stop corrosion. Maybe that's it.

Tim
 
Deelee said:
Interesting... something maybe they can look at during annual later in March... But your guy didn't find any leaks??
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No, but there was some oil pooled down there that he cleaned up. There is a lot of fittings in there. A week later we were back in there...which is another story...and it was still dry.
 
It's just a hat section stiffener with a drain hole. What's leaking out is whatever found it's way in there to begin with, that's what the drain hole is for. You've probably got lots of more important stuff to worry about.
 
Deelee said:
ACF-50, I believe... have to check the logs. But I think that's what was done.
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I like ACF-50 but it will weep out of every crack and crevice for a long time! It's worth it though ... if that's what it is.
 
Silvaire said:
It's just a hat section stiffener with a drain hole. What's leaking out is whatever found it's way in there to begin with, that's what the drain hole is for. You've probably got lots of more important stuff to worry about.
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Lots of more important stuff like what to worry about?

Makes sense that it is a drain hole. And Jim K's experience with the emergency gear extension valve leaking seems to make sense... that may be an area where we can point the shop that does the annual later in March.
 
Deelee said:
Today, was bored silly so went out to wash-wax-all the plane. Got ambitious and started cleaning the bottom from tail first to nose. Got about two feet forward of the baggage compartment and stopped because I am pretty sure I need a heavier duty degreaser (it aint' bad, but wash-wax-all ain't cutting through it).
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I like aviation simple green for the belly.
 
Just a drain hole so that water, oil, or whatever doesn't collect in that stiffener.
 
asicer said:
answer is always "money".
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AHHA I'm sure that will be the case regardless.... first annual with this plane coming up in March.... d'oh

wilkersk said:
Just a drain hole so that water, oil, or whatever doesn't collect in that stiffener.
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Makes perfect sense. But... Rookie question - how could oil get inside that stiffener? Does it run all the way up to the engine bay? We do have some nagging engine oil leaks... could that somehow make its way into that stiffener and out the drain hole?
 
asicer said:
Whenever the question is "what's leaking out of my airplane" the answer is always "money".
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Actually, yesterday, I fixed an oil leak without having to spend a dime.

Oh, wait. Just getting to the airport costs me $4.00 in bridge tolls. And it took three trips.

But I'm reasonably sure it's fixed.

And, we won't talk about how much it cost to get the leaking seal in the water pump (Rotax 912) fixed which started the chain of events that resulted in the oil leak.

Never mind. You were right. The answer was money.
 
Deelee said:
...Rookie question - how could oil get inside that stiffener? ...
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It's just riveted on, it's not sealed. Anything running down the belly is going to work it's way in there and they knew that, thus the drain holes.
 
Silvaire said:
It's just riveted on, it's not sealed.
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*rubs beard and looks acedemic-like...* iiinnnnteresting... very iiiinnnteresting indeeeeed....

So if oil was leaking somehow from the engine (maybe from the nagging leaks we have still...) it could possibly find its way in to one of those stiffeners and then out the back drain holes? and if possibly water got in there, it could possibly run out and drip there, too... possibly with a tan-ish colouring maybe from running down the same channel as the oil?
 
Deelee said:
AHHA I'm sure that will be the case regardless.... first annual with this plane coming up in March.... d'oh



Makes perfect sense. But... Rookie question - how could oil get inside that stiffener? Does it run all the way up to the engine bay? We do have some nagging engine oil leaks... could that somehow make its way into that stiffener and out the drain hole?
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Believe it or not, any oil leak from your engine is likely to find its way onto your lower firewall, in the lower-pressure area below the baffling. From there, it'll find any number of pathways into every nook and cranny along the belly of your airplane.

Last year, I had an oil cooler fitting leak on the Sonerai. After I got it fixed, I spent a great deal of time cleaning the belly and underside of wings. A year later, I took the tail feathers off to inpsect the horizontal stab for cracks and corrosion. And, I find a little engine oil on the tail post!
 
Deelee said:
AHHA I'm sure that will be the case regardless.... first annual with this plane coming up in March.... d'oh



Makes perfect sense. But... Rookie question - how could oil get inside that stiffener? Does it run all the way up to the engine bay? We do have some nagging engine oil leaks... could that somehow make its way into that stiffener and out the drain hole?
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How old is your plane? How many quarts of oil have been run through the engine? How many quarts have dripped and leaked out over that time?

It is a drain hole for the stiffeners that run the length of the cabin. They are not sealed, so all sorts of water, oil, soap, etc can find it's way into the cavity. As long as the drain is open, you are golden. If ACF has been sprayed, golden +1. Keep the drain holes open and doing their job.

PS There are other drain holes under there. Are they open? ;)
 
One time my oil filler cap came loose and made a big mess. It may have been my fault but regardless I cleaned it all up and replaced the gasket and it's been good ever since - over two years - but there is one rivet on the cowl that after every flight has a little stream of oil oozing from it. I've thoroughly cleaned all around it, inside and out yet it just keeps coming. So yea, that oil is sneaky stuff it can get into and hide in places you don't even know exist.
 
wilkersk said:
Believe it or not, any oil leak from your engine is likely to find its way onto your lower firewall, in the lower-pressure area below the baffling. From there, it'll find any number of pathways into every nook and cranny along the belly of your airplane.

Last year, I had an oil cooler fitting leak on the Sonerai. After I got it fixed, I spent a great deal of time cleaning the belly and underside of wings. A year later, I took the tail feathers off to inpsect the horizontal stab for cracks and corrosion. And, I find a little engine oil on the tail post!
Click to expand...

I had cars like that :-0 I preferred to refer to it as 'continuous undercarriage corrosion protection system' :idea:.
 
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