Help! Covering KF3 wing

[Bluebird19kf]

The manual says to cover capstrips ect. with polybrush then turn wing upside down then in step 2 says to use poly tack and cement the fabric to the cap strips. Then it says “do not use this process for the bottom of the wing.” I’m lost, what am I supposed to do then? Seems weird to say do this then say do not do this. I must be missing something!

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[Planesmaker]

Follow the polyfibre manual ! Polytak surface where fabric will be attached, then use polytak to attach fabric.

[aviator79]

Follow the polyfibre manual ! Polytak surface where fabric will be attached, then use polytak to attach fabric.

Specifically, follow the instructions in the PolyFiber Manual for undercambered wings. I think they are in an appendix, or at the end the "Let's do a wing" section. I don't think any part of the Poly Fiber manual tells you to coat capstrips in poly brush. I think if you're unsure, it's hard to go wrong by doing what's in the PF manual. The Poly Fiber STC is based on following those instructions to the letter. Not that you need the STC, but you can take comfort in knowing that what you've done has been evaluated and certified.

[avidflyer]

The undercambered wing is covered in the appendix of the poly fiber manual. Page 97 in my manual. This may shed some light on the subject. By the way, are you rib stiching? JImChuk

[Bluebird19kf]

Yes I plan on rib stitching. I was planning on following the poly manual then had second thoughts because I read where people were saying just to follow kitfox manual because 1000’s have been done like that and it works. The polyfiber manual is very clear and well written too.

[avidflyer]

If you are rib stiching, it probably doesn't matter either way then. Maybe wouldn't matter if you weren't ribstiching either. 1" wide cap strips have a lot of surface area to glue the fabric to. Just have to be careful not to get to hot and to close to the rib when you iron. JImChuk

[Jfquebec]

It is what i do for my model 4..i put two coat of poly-brush everywere on the wing (leading edge,trailling edge,ribs,tank and false ribs)after like they said in appendice C.i glue the top first and after the bottom but not on the ribs,i am not sure but i think i heat at 250 and made all the ribs stiching to old the fabric under before to heat at 300 and 350 (i made reinforcement in trailling edge)
I follow both polyfiber and Kitfox instructions
But i think it good to follow appendice C and the part for wood bonding on polyfiber manual..i dont use polytak on the wing...i think the new model use now polytak but im not sure..

[Jfquebec]

Sorry...i glue everything (under ribs to)and heat at 250 and do the ribs stiching 👍

[Planesmaker]

It is what i do for my model 4..i put two coat of poly-brush everywere on the wing (leading edge,trailling edge,ribs,tank and false ribs)after like they said in appendice C.i glue the top first and after the bottom but not on the ribs,i am not sure but i think i heat at 250 and made all the ribs stiching to old the fabric under before to heat at 300 and 350 (i made reinforcement in trailling edge)
I follow both polyfiber and Kitfox instructions
But i think it good to follow appendice C and the part for wood bonding on polyfiber manual..i dont use polytak on the wing...i think the new model use now polytak but im not sure..

I would follow poly fibre manual to the letter. The poly rush everywhere sounds like a typo mistake to me. Polytak is what should be used.

[aviator79]

Bonding to the ribs is unnecessary if you rib stitch, and is in fact discouraged by Poly Fiber. The exception is for undercambered wings which get bonded to the bottom capstrips to hold the fabric in place until the ribs get stitched.

Now, in all likelihood, you can bond your fabric to the capstrips with an Elmer's glue stick if you want, and if you do everything else according to Poly Fiber's recommendations, your fabric will do its job just fine.

However, if you want to remove all doubt, just follow the instructions from Poly Fiber. No matter how many kitfoxes are flying with poly brush on the capstrips or poly tak thinned with holy water and monkey ****, there are many, many more that have been covered according to the Poly Fiber STC. So when you have doubts, just go by the book instead of listening to Leroy.

[Planesmaker]

Correction, having just reread poly fibre manual, please disregard my last statement above. The poly fibre manual is the authority for applying their products.