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ILikePike

Well Known Member
I have a hard time drilling holes in a perfectly good airplane but where should drain holes be drilled and what size? I already know about the one in the snorkel. I am asking specifically about the RV-8 sitting on the tail wheel where water may pool up.
 
Drains

Also 1/8" in bottom of rudder fairing as well as in front of each bulkhead .

Just think about where water could collect and alter wt and balance after a heavy rain.

Think about that water freezing if it remained inside.
 
ILikePike said:
I have a hard time drilling holes in a perfectly good airplane but where should drain holes be drilled and what size?
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I put a hole at every bulkhead. I think the plans say a #30 hole. It needs to be big enough to break the meniscus or it won't drain the water. You can do an experiment with a can, drill a #40 hole, fill with water, and see if it drains. Then drill up to a #30 and see if it drains to your liking. If not keep drilling up until you like how it flows. The thicker the material the larger the hole will need to be.
 
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If you look the bulkheads have a natural drain path until the F-810 bulkhead. I have a #30 hole forward of that.
 
I like to see drain holes under fuel systems valves/pumps in case something develops a leak.
 
Drain Holes That Work

My Cessna 180 has tiny drain scoops that face aft and let drain water out, one per bulkhead. It's part number S-349, shown on the early parts manual on figure 33-46.

They work well.

The drain holes themselves are about 1/4" diameter, and that size is functional even if there's some debris trying to clog the hole - as there will be when you really want the drain holes.

And thanks for the reminder.

Dave
 
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When I brought the Rocket home and following its initial inspection, I flushed the fuselage with solvent, then hot soapy water, then just clear hot water. I drilled a 1/4 hole everywhere the water pooled. I started much smaller, but there was so much debris and leftover building junk that it would not drain.

Also had the opportunity to fly through some extensive rain recently, and despite cruise flight for an hour in clear air afterwards, landing, and and a LONG taxi to the the gas pumps, the airplane was STILL draining water after the tanks were topped.

I cant imagine how long I would have waited if the holes were #40's!
 
Randy Hooper said:
I think in fuselage construction instructions and if I recall correctly it's optional.
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Also depicted on DWG 74, which shows all the skin rivets. As you said, it's called out as optional, and they specify a #40 hole, though other experience here seems to indicate that #30 might be a better choice.

I'd be interested in hearing any experiences with water collecting and/or draining from the tail. Would this be a natural consequence of, say, parking the plane outside in a rainstorm?
 
I couldn't find any info in the manual but found the notes on dwg 74. After looking at the fuselage sitting in the shop, I think 2 #30 holes may be all that is needed in the fuselage. I am thinking one in front of F-806-1 and one in front of F-807-1 dilled through F-827-1. Behind F-807-1, it seems that the spaces between the former tabs will drain water out of the tail wheel mounting bolt hole. May need some holes in front of F-807-1 behind the flap pushrod holes. What about forward of the spar?
 
I hate to through this number out there but, per MIL-HDBK-1568 materials and processes for corrosion prevention and control in aerospace weapons systems, drain holes should be 3/8"...
 
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