Wing Covering

[Av8r3400]

To those of you who have decided to rib stitch your wings, did you still glue the fabric to the rib cap strips or did you let it float, only gluing to the leading and trailing edges, like a certificated fabric covered plane?

[jiott]

I followed the SS7 build manual and precoated the rib cap strips with diluted Polytak cement, then covered with fabric, then shrunk with heat, then brushed on MEK to activate the cement on the cap strips, then rib stitched. On the bottom undercambered part I only shrunk part way with heat and then activated the cement and let it dry with weight on it; then finished shrinking and rib stitched.

I think it is important to let it float while shrinking, then glue it down after it is in its final position and tension.

[jrevens]

I basically did the same thing with Oratex also - applied glue to the capstrips, but didn't activate it with heat & pressure until after the initial shrink.

[avidflyer]

With all the rain up here, I actually started recovering the second wing for my Avid yesterday. I reviewed the Poly Fibre manual a bit, and in the section near the back of the book that deals with undercambered wings, it says to not glue the top of the wing if you are going to ribstich. Of course you had to glue the bottom to keep the fabric from ballooning away from the rib when you shrink the fabric. I would imagine not glueing the top of the ribs would help the fabric to have a more even stretch overall. I have to admit though, as long as I already had the two coats of poly tac brushed on the top of the wing ribs, I glued it down. (belt and suspenders) Jim Chuk

[Av8r3400]

Thanks for the replies, gents.

[t j]

I poly brushed the bare cap strips top and bottom but did not poly tack them.

[jiott]

I also noticed that the Kitfox instructions differed from that section in the Polyfiber manual. However, John McB encouraged me to just follow the Kitfox manual since they have been doing it this way for years with good results. If you think about it, by gluing the ribs you add strength to the wings with all those independent box sections between ribs. The tensioned fabric acts like thousands of little tension cables to resist bending and twisting. Stronger than one big box section. Most modern bridge girders are built this way. By heat shrinking before gluing you get nice even fabric tension all along the wing. My 2 cents worth.

[Jfquebec]

Hi guy's...i started to cover my wing last week...so i read lot of time the covering book of kitfox and polyfiber...in polyfiber book they said never use polytak on plywood...so it is what i sctoch bright and clean all the wing...i put two coat of polybrush everywhere on the wing and the tank(i sand the tank with 220)
After i start like kitfox said,by the bottom ..under the wing ...li start to gluing all the rib capstrip from center...after leading and trailling edge...i smooth all cement place with iron at 225...and i heat shrink all the fabric at 250 ...

Top wing...
For the top wing i start to cement the leading edge with polytak....and same thing with trailing edge the two ribs at each tip...that it's...im there right now..
Ho! I started to iron all the edge...so after that(im at work for two week) i will heat shrink all the top to 250 and i will start to rib lace all the wing..and heat shrink to 300 and 350 ( i install reinforcement in trailing edge)
After that one coat of polybrush with a brush,,,reinforcing tape inpection rings,drain grommet,an other coat of polybrush and tree cross coat of polyspray..
I hope i doing that right...sometime it is confused beetween kitfox and polyfiber book...i will try to make a little video of my covering...let me know your own tip's
Jf

[jiott]

I believe the book says to heat shrink to 350 BEFORE gluing to the capstrips (except for the end ones) and before rib stitching. That's the way I did mine.

[Jfquebec]

You are right...but if you look for the undercamber wing ...they says to cement it first and make the rib lacing before 350 heat..but i do like you on the top..

[jiott]

The Kitfox 5-7 wings have very little undercamber and it is no problem gluing the fabric down after the 350 shrink; just use some weights to hold it down while the glue sets.

[Mpaul]

Looking to recover one wing from a KF 2. Using no rib stitching as in the original build do you recommend using poly brush or poly tac on the rib caps before shrinking or use mek and activate the tac or brush after shrinking. Also looking for a Bulid Manual for KF2 to buy at reasonable price. Also looking for a set of flaperons for the KF2 or someone who has the skins to build a set. Thanks

[Jfquebec]

This is from polyfiber site...


What about attaching the fabric?
>You will attach the structure using Poly-Tak cement. This means attaching it on leading and trailing edges, wing butt ends, etc. Do not use Poly-Tak to apply the fabric onto the surface of the plywood itself.

[Jfquebec]

This to...


What holds the fabric to the plywood if I can't rib lace or attach it in any other way?
>As you know, the fabric must adhere to the plywood surface. This is particularly important on a lifting surface such as a wing. Poly-Brush is applied over the fabric which then penetrates through the fabric activating the Poly-Brush you have applied directly on the plywood. Be sure you brush this coat of Poly-Brush onto the fabric. After this step you follow the remaining steps in the manual.
*

[avidflyer]

When it talks about attaching to plywood, it's not referring to cap strips on the ribs. Some planes have fairly large surfaces of plywood (or fiberglass) under the fabric. They are talking about how to get the fabric to adhere to those areas. Jim Chuk

[jiott]

Just follow the Kitfox build manual (SS7). It says to precoat the rib capstrips (after epoxy varnish) with two coats of PolyTak and let dry before applying fabric. Then after covering and shrinking to 350, activate the PolyTak underneath with MEK and it will glue the fabric down (use weights on the undercambered parts). Then apply PolyBrush, rib stitching, tapes, etc.

This is slightly different than the Polyfiber manual, but is tried and true for the later model Kitfoxes per the factory.

[HighWing]

Just follow the Kitfox build manual (SS7). It says to precoat the rib capstrips (after epoxy varnish) with two coats of PolyTak and let dry before applying fabric. Then after covering and shrinking to 350, activate the PolyTak underneath with MEK and it will glue the fabric down (use weights on the undercambered parts). Then apply PolyBrush, rib stitching, tapes, etc.

This is slightly different than the Polyfiber manual, but is tried and true for the later model Kitfoxes per the factory.


I might say that the old technique recommended in the early build manuals is also tried and true. I would suspect that of the first 2 or 3 thousand Kitfoxes built, all the wings were then covered using the technique in the Kitfox build manual - sequentially gluing the fabric to the capstrips with Polytack, then gluing the leading and trailing edges. I am always intrigued by the evolution of the build techniques. In the early manuals - at least my 1993 manual - rib lacing was listed as an option, but I suspect the vast majority of the early airplanes were not riblaced with only rare mention of pulling away of the fabric from the undercambered lower wing surface and that even with the I,II and III steeply undercambered wings.

The only thing that bothers me with the new technique is the shrinking before gluing on the bottom of the wing. As I understand it, the rationale is even shrinking across the length of the wing. Given the choice, I would prefer even gluing than even shrinking, as comments on uneven shrinking are even rarer than comments on fabric pulling away. But that is just me.

[Jfquebec]

When i start to cover the wing i read both book..my is a 4 1200..1993..
So to polyfiber book to kitfox book...it is sometime confused for me..

I dont have my both book here...and when i will come back to my home in two week i will re read everything to make sure i do it right...

And to make it more hard...im not perfectly good in english...(im frenchi:cool:)
So i need to read ,traduce....and re read ..it is not easy especialy for covering.:(

[mr bill]

Using Stewart System adhesive, on the bottom of my wings, I bonded fabric to the ribs then heat shrank. On the top surfaces, I heat shrank then bonded to the ribs. Instead of stitching, I used the same pop rivets that War Eagle used. I drilled the holes in the ribs for the pop rivets before covering and added a drop of crazy glue to each hole to stiffen the wood. It all worked well.

[Spook712]

Hi guys, I'm thinking about re-covering my wings.

Has anyone the measurement of the wing ( area to be covered ) handy
length and width of the speedster wing is what I need.

Or how wide has the covering material to be for upper/lower lay-up or wrapping the wing.

Thanks
TUNA