That's really small! I'll check that out... should help me find the blue stains if I can poke it into the long, narrow space between the leading edge skin and the front spar's web. Thanks, Rick.
Terrence L235/320 N211AL
On Mon, Jan 31, 2011 at 7:17 AM, Rick Lafford wrote:
For interior inspections, check out Harbor Freight. They have a relatively inexpensive video inspection camera that gets into tight spaces. I bought one and found it would even fit through the plug holes on my O-360. Rick RV-6 N146RV From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Terrence O'Neill Sent: Sunday, January 30, 2011 10:32 AM To: lml@lancaironline.net Subject: [LML] Re: Weeping wing tank. super cool trick to fix it!!! Neat. I didn't know about the bubbles adn amplifying the sound. I made a manometer so I can limit the vacuum to about 6 inches water... and I just bought some PR-1005-L ... a quart. I think that'll be enough, as the leak seems to be in the upper part of the front spar web. Doesn't leak when below 78 gallons in the tank. Many thanks. Terrence 235/320 N211AL On Jan 29, 2011, at 10:36 PM, randy snarr wrote:
Terrence, Take a deep breath. I had a similar issue on mine and the cure was not that bad. I have a trick that should help..
First the bad news, Remove the wing. (drain fuel first duh..) leave about a pint in the tank.
Once the wing is off you can find the leak by putting a small amount of negative pressure on the tank and seal it up. You have to seal everything off first. I would connect a tube to the fuel or vent line and just suck on the tank with your mouth and then seal it off. You dont need much. I found this completely by accident. You never get all the fuel out and in this case that is ok. A pint of fuel in the tank is good for this trick. With a little negative pressure on the tank, rotate the wing and force the fuel around all the corners in the tank where the suspected leak is and listen carefully with your ear. When the fuel covers the hole in the tank you will hear the air bubbles passing through the fuel as it enters the tank. The empty wing is like a drum and the sound is amplified. I had a leak and found it at bottom front corner of the tank where the tank close out rib meets the lower skin forward at the spar. Now you know where the leak is.You can now remove the pint or so of fuel and dry out the tank. I used an alum rod with paper towels taped to the end to get it dry in the corner where gravity collects it. Once it is DRY. orient the wing so the leak is where gravity will take your sealer. I used the same gray epoxy based tank sealer lance recommends. U used a large seringe ( like for a cow) and injected about 1 cup of gray sealer as close to where the hole is through the gas cap hole. You wont be able to see any of this but you can do it by feel. Move the tank around slightly to completely cover the entire area where the hole is. I would seal up the tank again and put the negative pressure back on to push some goo into the leak hole for 20 minutes or so. Release the negative pressure and Support the tank with the hole at the lowest point and let it cure. Shazam, no more leak. Hope that helps.. Best, Randy Snarr 235/320 N694RS
( i mean real small as you can collapse your wing with too much!)
"Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible" -Simon Newcomb, 1902
Subject: [LML] Weeping wing tank. Date: Monday, January 24, 2011, 5:57 AM
This is a request for info on the possible similar experience of other LNC2 builder-fliers... a wing tank fuel leak.
The very slow leak through the front wing spar, when fuel leveel is above about half way up, is of course uninspectable because of the leading edge -- and further because it is possibly behind the root area secondary web ... not to mention the fact that the spar web is sandwich construction and the interior skin leak can propagate spanwise to another portal in the forward web skin.
So my question is, when I slosh-seal the tank, what is recommended as a prep for the tank inner surface? I've read MEK and another TankPrep stuff.
For sealant I've looked at PR-1005-L, and at the automotive (supposedly) stuff, and phenol novolac. Any suggestions soulfully appreciated, for this worrisome job. Thanks.
terrence N211AL LNC2 235/320.
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