Draining water from Fuselage

PaulR · #1 01-06-2012, 12:36 PM

Most if not all, of the airplanes I've ever flown have a small drain hole rearward (tricycle) of each bulkhead in the fuselage. I haven't seen anything in the plans about this though I may have missed it. I did a quick search and found a couple of threads that talk about it a little but nothing definitive.

So, I'm thinking just aft of the each bulkhead and probably also in the airbox. (carbed) Maybe an 1/8 or 3/16 hole to allow water to leave. What does everyone else do?

terrye · #2 01-06-2012, 02:17 PM

I haven't seen anything in the builders instructions about water drains either. And what about the wings? Are these self draining because of the dihederal angle. I know there are fuselage drains in my C-150 as PaulR has said, I also notice a few drain holes in the bottom wing skins near the aft spar.

TroyBranch · #3 01-06-2012, 04:17 PM

In canada we require these holes in order to pass the final inspection. I drill a 1/8 hole in the low point of the fuselage in every second rib bay.

kevinh · #4 01-06-2012, 05:36 PM

There is a small note in the plans about this. Just as you describe a #30 hole just aft of each fuse bulkhead.

Walt · #5 01-06-2012, 05:43 PM

Quote:

Originally Posted by TroyBranch

In canada we require these holes in order to pass the final inspection. I drill a 1/8 hole in the low point of the fuselage in every second rib bay.

Troy has it right,

Plus... I always put a hole where the fuel pump resides so in case there is a leak the fuel has a path to drain overboard and not accumulate

Don't forget the rudder fairing and inlet airbox as well.

Flying Scotsman · #6 01-06-2012, 11:27 PM

Quote:

Originally Posted by kevinh

There is a small note in the plans about this. Just as you describe a #30 hole just aft of each fuse bulkhead.

There is???? I don't recall seeing this, but then again, I've parted company with the plans a while back once I got to FF stuff...this is a good topic and I'm very inrerested to know if there are any suggestions here...

Thanks...

Steve

PaulR · #7 01-07-2012, 06:59 PM

Walt,
Is a no. 30 or 1/8" big enough? Seems like the surface tension on water might be to great to allow it to drain. Good idea about the boost pump. I wouldn't have thought about that location.

Ron Lee · #8 01-07-2012, 07:05 PM

Paul, find some scrap aluminum and make a depression to hold water (actually it could be a can).

Fill it with a certain level of water. Maybe 1 inch. Drill a small hole (perhaps 1/16"). If it does not drain (surface tension/head issues) drill a larger hole.

Continue with less water depth until you determine what size hole is needed for the depth water you want to drain. Obviously the hole has to be larger for shallower water depths.

I will have to measure what I did but a wag is around 3/16" hole.

bruceh · #9 01-07-2012, 07:41 PM

The only drainage holes I've seen on the plans for the RV-9A are on DWG 7, Note 3:

Add 1/4" dia. drainage hole to R-911 (Rudder Bottom) at low point when the airplane is in ground attitude.

I haven't drilled any other drainage holes in the fuselage. If there is direction in the plans to do that, I would like to see it.

It is things like this that would make having the plans in digital form so much better for searching... Imagine being able to "google" the preview plans and build instructions.

scard · #10 01-07-2012, 07:49 PM

Quote:

Originally Posted by PaulR

Walt,
Is a no. 30 or 1/8" big enough? Seems like the surface tension on water might be to great to allow it to drain. Good idea about the boost pump. I wouldn't have thought about that location.

I agree, #30 and 1/8" is too small in my real world experience. Just a little bit of dust collection compounds the problem of clean surface tension. I opened mine up to almost 3/16" after finding non-draining water.