Leading Edge Fabric Issues

Hi all. Not a Super Cub owner, but a recent owner of a Piper Pa25-150 Pawnee. I've been a lurker here for a quite a while so I know that alot of knowledge is shared here. Any advice at all here would be greatly appreciated. The Pawnee i recently purchased was stored in a barn for about 15 years, new fabric on fuse and wings at time of storage. Fuse was completed through Poly-Tone, but wings were only through Poly-Brush. Fabric on wings tested good by break test at Poly-Fiber in California. Sprayed two cross-coats of Poly-Spray on the wings and the silver really made the imperfections in the leading edges of the wings stand out. The wings were stored in the barn, hanging trailing edges up, and "grit" or some type of small particle got wedged between the fabric and leading edge skin, leaving tiny bumps on the leading edge under the fabric. I cut several small slits in the fabric to ensure it wasn't corrosion, but the aluminum leading edge skins are bright and shiny (minus the Poly-Brush) so no corrosion. What is the best way to remove the "grit" from under the fabric and still have an airworthy yet decent looking leading edge? Appreciate any ideas.

Kyle

the grit got in there when fabric was loose before shrinking and someone rolled wing leading edge down...

only way to try is poke small hole in a tape and use a long needle with hooked end and try to pull chunks off back edge of leading edge....

might be faster to cut some holes....

or just accept what you been dealt ....

Looks like that was a fabric wing sock used when covering. Most likely crap got in there at time of cover. I don't think there is an easy way to get that crap out because once you start looks like you could just keep going down the entire wing. Might just be easier to strip it down and recover. You could always just finish painting and have whatever new guy is spraying use it until it has a big dent in it and recover than.
DENNY

edit: Mike beat me too it:lol:

Evil Spirit in my parking brake valve got me a few years ago and I flipped my little cub over in my pasture. bent both front spars but little damage aft of leading edge. Cut fabric along leading edge and pealed fabric off leading edge. Did repairs then Polly tacked fabric back to repaired leading edge. Polly tacked a strip of fabric over the seam with 3 or 4 inches overlap then finish tapes. Used heat gun to restrink fabric. Poly tone finish so alittle more poly spray and some paint and presto. Seems like a big deal but really wasn't. Food for thought.

If it were me.... that would drive me nuts! I agree, it was a screwup at covering time. I've seen a few do that. I'd be really tempted to pull the leading edge tape, slit the leading edge fabric and clean that all out, then lay in a "patch" with a 2" overlap to each piece of leading edge fabric glued in, then cover that whole mess with a 6" tape from root to tip. Just remember the STC calls out for a 2" fabric to fabric overlap on a cemented seam on the leading edge.
John

Heck, it's a Pawnee: That'd win "Golden Wrench" award for best Pawnee cover job at Oshkosh. Well, maybe Oshkosh, N'braska.... ;-)

Seriously, good advice from some guys who really know this stuff. What do you plan to do with this bird? And be sure to let us all know how it turns out so we can learn from this.

Thanks. cubscout

Here is what you do - sand those puppies off. Some will fall out the holes your sand paper makes, others won't, but you will get a smooth surface. Then get some new fabric and do a "surface tape" from 1" behind the spar on top to 1" behind the spar on bottom. Be sure to use pinking shears, and be sure to mark with a pencil first.

before you glue the giant surface tape on, brush more Poly Brush on the leading edge, and sand more if you have to. Fill any deep holes with something. Glue the giant tape down 2" from each edge, and when the glue sets, shrink it to fit your now smooth leading edge. Work in another coat or two of Poly Brush all over the new tape, and proceed to spray.

I agree with Mike, happened before the fabric was shrunk. Gotta clean the wing well before cover and blow out with compressed air and always rotate trailing edge down. Learnned that the hard way on my own wing many years ago. I would use an exacto knife and apply a nice pinked patch like Bob suggested.

Thanks guys for the responses! Lots of great ideas and solutions. I especially like the idea of the big patch after removal of the crap. Should be pretty easy to do and should clean up the leading edge in those areas. I'll keep y'all posted. Thanks again!!

Kyle

Do you know what is best to use in order to protect the leading edge of elevator when operations include gravel strips?
A tape of some kind Or?
Thanks
Tom

They make that black tape, Pretty tough stuff. Call Stoddards they should have it.
DENNY

drt said:

Do you know what is best to use in order to protect the leading edge of elevator when operations include gravel strips?
A tape of some kind Or?
Thanks
Tom

Click to expand...

I've tried masking and truck bead liner paint on stuff. Not sure what the results were long term.


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DENNY said:

They make that black tape, Pretty tough stuff. Call Stoddards they should have it.
DENNY

Click to expand...

That's what I have on mine. It's been on there for more than 10 years and still looks good. Got it at Stoddards.

Thanks! Tom

Thanks Denny,
Will give it a try.
Tom

Excellent.
Thanks Tom