VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 05-08-2022, 01:13 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,358
Default Drain Hole Diameter vs. Drain Time

Since I hadn't seen any quantitative data for this, I decided to test it.

The test set-up was an empty 4 oz. can of chiles, set up on a rack in the kitchen sink so that I could have ready access to it. I’d fill the can from the faucet and start the clock when I moved the faucet away. This gave me a consistent timing set-up. I tried #40, #30, #19 , 3/16” and 1/4” holes.

Here’s the raw data:

#40 took 82 seconds
#30 took 52 seconds,
#19 took 30 seconds,
3/16” took 25 inches and
1/4” took 15 seconds.

Except for the 1/4” hole, all had at least some water remaining, generally .03 to .05 inches. The smaller holes had more variability for the time remaining, so I averaged the times. I did each at least twice.

Here’s a chart, with seconds on the vertical axis and hole diameter on the horizontal axis.



I'll probably use 3/16" or something between that and 1/4".

Worth noting is that my 1955 Cessna 180 has some nice snap-in fairings for its 1/4" drain holes. But they don't seem to be in the parts manual and I don't have a part number. They are roughly similar to the "seaplane" grommets AN231-4 used for fabric airplanes, but metal and they pop into the holes. With a decent glue, I'd imagine that the seaplane grommets would work but I didn't test any holes with them.

Dave

Last edited by David Paule : 05-08-2022 at 04:38 PM.
Reply With Quote
  #2  
Old 05-08-2022, 04:31 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Southwest
Posts: 2,323
Default time

So what drain time is good enough?
__________________
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Dues paid 2022, worth every penny

RV9A- Status:
98% done, 2% left to go
Structure done (less gear)
Electrical/Panel done
Firewall Forward 95% done
Fiberglass 90%
www.pilotjohnsrv9.blogspot.com
Reply With Quote
  #3  
Old 05-08-2022, 04:39 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,353
Default Drain hole

Which drain hole?
Fuse, or intake?
__________________
Larry Larson
Estes Park, CO
wirejock at yahoo dot com
Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved (3,000+ hours)
Empennage, wings, fuse, finishing kit done. Working FWF
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #4  
Old 05-08-2022, 04:41 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,358
Default

Even the smallest hole I tried had a steady stream of water from it, until the water got to within maybe 1/4", when it started dripping. Should have mentioned that. The larger holes had less drip time and less water remaining.

You'll have to decide for yourself what size hole to use - but this at least gives you a basis for that decision.

Dave
Reply With Quote
  #5  
Old 05-08-2022, 04:45 PM
terrye terrye is offline
 
Join Date: Feb 2010
Location: Vancouver, BC, Canada
Posts: 998
Default rain Hole Diameter vs. Drain Time

"3/16 took 25 inches and" I think you mean 3/16" took 25 seconds?

I assume this is fuselage/wing water drain holes? My C-150 has approx 1/8" dia holes in the bottom skin on the aft side of each bulkhead. When they made the hole it looks like they took a 1/8" punch and levered it aft after they drilled the hole, I guess so it would suck out in flight.

To me, 3/16" or 1/4" water drain holes are just asking for wasp nests inside the structure, even if the plane is in a hangar.
__________________
Terry Edwards
RV-9A (Fuselage)
2021/2022 VAF Contribution Sent
Reply With Quote
  #6  
Old 05-08-2022, 06:35 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Southwest
Posts: 2,323
Default Just me

Terry I think you have a point. I plan to use #40 drain holes unless someone has a reason to go bigger. .
__________________
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Dues paid 2022, worth every penny

RV9A- Status:
98% done, 2% left to go
Structure done (less gear)
Electrical/Panel done
Firewall Forward 95% done
Fiberglass 90%
www.pilotjohnsrv9.blogspot.com
Reply With Quote
  #7  
Old 05-08-2022, 06:48 PM
PaulvS's Avatar
PaulvS PaulvS is offline
 
Join Date: Aug 2019
Location: Western Australia
Posts: 1,124
Default

Quote:
Originally Posted by PilotjohnS View Post
Terry I think you have a point. I plan to use #40 drain holes unless someone has a reason to go bigger. .
One reason to go bigger is to avoid the drain holes being blocked by dust and small pieces of dirt that will accumulate over time in the fuselage. At least that is a consideration in dusty regions of the world.
__________________
Paul vS (yes I'm also a Van)
Building RV-6A #22320 O-320 FP. Wings and tail complete, fuselage almost done, working on canopy.
Flying my Aeroprakt A-22 STOL and the aero club's RV-9A while I build
Reply With Quote
  #8  
Old 05-09-2022, 08:44 AM
Hangar 1271 Hangar 1271 is offline
 
Join Date: Nov 2013
Location: Orlando, FL
Posts: 97
Default

For no good reason whatsoever, I decided to see if your numbers made any sense. Since the time to drain is mostly influenced by area and head (I can't begin to determine the impact of turbulence on this) and, assuming the most accurate time is the 1/4 hole, the time to drain would theoretically be:

Hole Time
40 ____ 98
30 ____ 57
19 ____ 34
3/16 __ 27
1/4 ___ 15


Your numbers are reasonably close to these.
__________________
David
RV-8 2019
SeaRey LSX 2014
305h@mazergroup.net

Last edited by Hangar 1271 : 05-09-2022 at 08:48 AM.
Reply With Quote
  #9  
Old 05-09-2022, 10:24 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,358
Default

Or you can get a can and try it yourself.

When I bought my C180, the interior was quite dirty. The plane was over 30 years old at the time and while the upholstery was fine, the belly and tailcone was loaded with the grease and debris that accumulates there. I stripped the interior, put the plane on grass and proceeded to spend a nice weekend scrubbing it out. I used a hose to rinse it, and found that virtually all the drain holes were clogged with grass and stuff. Several of those little snap-in drain things were misaligned. All that got fixed. I had water several inches deep at the bulkheads.... good draining can be important.

Dave
Reply With Quote
  #10  
Old 05-09-2022, 11:08 AM
stigaro stigaro is offline
 
Join Date: Aug 2020
Location: Ontario, Canada
Posts: 74
Default

Quote:
Originally Posted by Hangar 1271 View Post
For no good reason whatsoever, I decided to see if your numbers made any sense. Since the time to drain is mostly influenced by area and head (I can't begin to determine the impact of turbulence on this) and, assuming the most accurate time is the 1/4 hole, the time to drain would theoretically be:

Hole Time
40 ____ 98
30 ____ 57
19 ____ 34
3/16 __ 27
1/4 ___ 15


Your numbers are reasonably close to these.
Heh, I did the exact same thing but chose the #40 as baseline due to less timing error on the 82 seconds. I get:

Hole Time
40 ____ 82
30 ____ 48
19 ____ 29
3/16 __ 22
1/4 ___ 13

Pointless, yes.
__________________
RV-14A
Empennage - 95% complete
SB Wings - 80% complete
SB Fuselage - ordered Aug '21
Finishing Kit - ordered Jan '22
2022 Dues paid
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:55 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.