Belly drain holes

[pierre smith]

Mornin' everybody,
Yesterday water poured out of the fuselage when we started sanding the belly since we had washed it as we wet sanded primer and other areas. Do any of you drill holes at the bulheads to drain water? Seems to me that rainwater could come in around the tailfairing when you're parked outside. Should that be sealed with RTV?

[Rick6a]

Originally Posted by pierre smith

.....Yesterday water poured out of the fuselage when we started sanding the belly since we had washed it as we wet sanded primer and other areas. Do any of you drill holes at the bulheads to drain water? Seems to me that rainwater could come in around the tailfairing when you're parked outside. Should that be sealed with RTV?

Pierre,

You reminded me....I think drilling drain holes is certainly prudent. I plan to drill only one though, since I installed an Orndorff removable rear tie ring. That opening also serves double duty as a massive drain hole back there since in my case, the ring is not normally installed. I'm thinking I may not necessarily need to drill the forward drain hole up against a bulkhead as is typical (certificated) practice, at least that's the way it was done on my C-150 at EVERY bulkhead location. Rather, with the airplane parked in its usual location and the floor removed, I plan to pour a small amount of water from a paper cup onto the bottom skin and observe where it collects. Thanks for the reminder. I originally meant to drill that hole but somehow overlooked it.

[Ironflight]

On a cross-country last month, I landed at a small airport for fuel, and after climbing out, I noticed that the tailwheel was sitting in a puddle of water. I couldn't figure out how I managed to park in the only small puddle on the ramp...very strange!

On the next flight leg, I went to take a drink out of my water bottle - and it was empty! That's when I put two and two together, and realized that the taildragger drains just fine - all the way from the cockpit back to the opening for the tailwheel spring.

When I had the baggage compartment out later to install my Altrak Servo, I checked for any sign that the water had been there, but I guess when you rinse with clean spring water, there is no residue!

Taildraggers drain fine...

Paul

[vlittle]

Here's what I did (A model) and why:

I drilled two 1/4 drain holes at the low point of my fuse (below the seat area in the center tunnel). I inspected the aft bulkheads, and they all have flutes that will allow water to drain forward to this point. I drilled holes in pairs, thinking that if the airplane was not level, this would be more effective.

Then, I did the same thing directly below the fuel selector valve. Besides water, this will drain fuel in the event of a fuel leak in the area.

I fabricated small fairings to fit over the holes and bonded them on the underside of the fuse. Inside, I bonded on some stainless screen (from a faucet filter).

The fairings act to provide a slight vacuum in flight, pulling any liquid out. They also prevent any oil or exhaust from entering.

One other thing I did: right below the steps on my '9A', I left a small opening. (rather than sealing tight) This provides some outboard drain holes.

I didn't do anything special for the wings. Most of the water would work its way to the wing root and out at the root fairing.

I'd expect most water accumulation would occur if the aircraft was sitting on the ramp. I hangar mine, but sometimes fly in the rain (Vancouver BC area).

Vern