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Water Belly

texdog

Well Known Member
I noticed on takeoff from OSH that I had a heavy aft CG. Normal trim required a lot of forward stick. I landed an hour and a half south and water was pouring out of the belly aft of the baggage compartment. I had a Bruce cover on the cockpit, no wet seats, floor or instruments. How is the water getting in the belly? It happened once before in heavy rain.
 
I can't tell you how it is getting in, but I can tell you that it needs to be getting out via drain holes in the lower skin! If you don't have any, make sure that you add them.
 
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Fred,
That is a LOT of water retention to be able to feel in trim. I think I have two or three drains and a strategic pass through between each bulkhead. My second mortgage while building many years ago was a large sailboat, always thinking about the bilge.

1/8" is too small. You hate to drill a hole in anything, but H2O surface tension is stronger than most imagine. Add a little random surface contaminants over the years (dust and stuff) and a 1/4" hole does the trick if you find your baby parked a long way from home in a rain storm.
 
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I'd bet the water is running down in the fuselage/wing intersection, hitting the bottom fuse skin (which is wider than the rest of the fuselage) and being funneled inboard (which is downhill from the wings).

As Paul stated, drain holes are the solution.
 
I'd bet the water is running down in the fuselage/wing intersection, hitting the bottom fuse skin (which is wider than the rest of the fuselage) and being funneled inboard (which is downhill from the wings).
As Paul stated, drain holes are the solution.

And a nice proseal filet at the intersection of the side and belly skin. You can see the dark line here:
 

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I recall seeing a post a few months ago ,of as I recall, a -6A being restored/rebuilt that when the floor skins were removed the entire area under there was insulated and full of corrosion almost through the belly skin from water being trapped in it. I think the T/W aircraft do pretty fair at draining down and out but A models not so much.
 
I recall seeing a post a few months ago ,of as I recall, a -6A being restored/rebuilt that when the floor skins were removed the entire area under there was insulated and full of corrosion almost through the belly skin from water being trapped in it. I think the T/W aircraft do pretty fair at draining down and out but A models not so much.

Is this the area under the seats and baggage compartment? Kind of difficult to check as those floors are riveted down (at least in my case). I dont remember drilling baffle style holes in the rear lower baggage compartment bulkhead but assume any water from the wing root would drain out of the rear spar attach area on a taildragger. Did people put drain holes in the belly forward of that bulkhead?
Figs
 
The poster that found corrosion dealt with a plane that had foam insulation glued directly to the belly skin, would definitely be a water trap it got saturated in there.

In my builds, I drill 1/8 drain holes in lowest spot (when parked) in each fuselage cavity & drill a 1/4" hole in the bulkheads between each cavity. That way any collected water can drain either down & out or back & out. Same treatment for both TD & Tri Gears.
 
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