Wing Recover and Drain Holes

[stanleykirk]

I am currently in the process of recovering the wings on my son's 1946 140. When we removed the fuel tank we discovered about 20 (5 along each support) small holes along the fuel tank support braces. There were no holes in the fabric on the bottom side of either wing indicating that they were/are suppose to be drain holes.

Has anyone seen these holes in the fabric of your 120/140 under the fuel tank or had any experience with this??

[2356]

Fabric clip holes?

[stanleykirk]

I don't think so...oriented along the span of the wing and too far apart...but thanks for tryin'!!!

[stanleykirk]

Actually Huey Pilot...I was wrong about the holes...they do look like clip holes, however they are 1 1/8th inches apart and the other clip holes are 1 3/8th inches apart. I have been unable to find anything that indicates Cessna had two size fabric clips. I anyone knows differently...please enlighten me!!

[6643]

Here are the pictures. I have no idea! Anyone?
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IMG_8190.jpg (73.21 KiB) Viewed 2765 times

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IMG_8192.jpg (34.75 KiB) Viewed 2765 times

[6468]

Sometimes in the assembly/fabrication process (at the factory) it is not uncommon to use a small punch die jig to temporally stake (hold/position) two pieces of sheet metal during the spot weld process. If the staking holes are in a benign location you just leave them, in this case they'll be covered with fabric and posse no structural issues. Given the uniform spacing from row to row my bet is on the holding fixture. Still ... just a guess
Jim S

[stanleykirk]

Thanks...Sounds plausible too me!! Our main concern is if water does intrude the fuel bay could it pose a problem of water getting between the fabric and the bottom of the fuel bay and create a corrosion issue? Just spit ballin' here...and wondering out loud.

[6468]

On my aircraft I have 2 small holes in the back corner of each tank bay (about 1/4" dia.) They appear to be approx. 1/2 " away from spar & ribs. When covering I placed the plastic drain in line with the holes. Used the seaplane style all the way out to the ailerons then transitioned to the flat inserts. Suppose there could be a little moisture trapped along that last 1/2 " against the spar. FWIW the seaplane design by it's shape is suppose to siphon out the moisture, not just let it drop by gravity, course you need to be moving & there has to be an air inlet somewhere, in theory. Good luck
Jim S

[stanleykirk]

thanks Jim…i am familiar with those holes and we are planning on using the seaplane grommets as well. I think the holes we are seeing may be “alignment holes” as mentioned in the above post. they are quite small and probably won’t creat much of an issue, we shall press on with the project