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Anti-chafe tape on a wood wing

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Chris In Marshfield

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Hi all,

We're about ready to start covering the Double Eagle wing and were thinking about the materials and steps to completion. We'll need to put some anti-chafe tape on the ribs and other things before wrapping them.

The ribs are 1/4" stock. When we put the tape on the ribs, should the tape be at or slightly over 1/4", or would a standard larger tape be used and then wrapped around? I'm figuring that a fabric surgical tape you could get from the drug store is a good and readily available option.

What say you?

~Chris
 

TFF

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You should not tape all the wing ribs. Tape is used for sharp spots. If you are going to go cord length along the ribs, you would get strips of fabric and attach them to the ribs. I did not add anything to my ribs. Used very little chafe tape overall for the whole plane.
 

Chilton

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On the vintage planes I work on, the standard is Sellotape (may be a different name in the USA) over the ribs, just layed along the cap strip, normal available stuff is about 3/4 inch wide so it hangs over the sides. That stops the fabric sticking and distorting the ribs.

On a metal rib wing like the piper cubs we use gaffer tape to cover anything which might rub such as the screws and leading edge panel joints before the sellotape goes on the ribs.

With the arrival of Ceconite and the shrinking of the fabric before the first coat of dope many people stopped taping the ribs but enough movement happens later on that I will certainly continue to use tape unless working on something whee fabric is glued to the ribs rather than stiched or riveted.
 

TFF

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Fabric is not glued to ribs usually. ULs are an exception if you want to trust it over lacing.
 

Chris In Marshfield

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Since these wings had been previously covered, there’s some residue from the last installation that’s a bit crunchy/sharp, hence the question if the tape. If it’s better to try cleaning the residue off by sanding it smooth rather than taping it, then we’ll do that..
 

n45bm

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Another question along the same vein, but slightly different. On a wooden airplane, should the ply-covered areas like the fuselage, etc. be varnished before covering with fabric? I did not due that on my Stits fabric covering on my Corby Starlet, but I've seen other wood aircraft be varnished before covering. I have not had issues with the covering loosening or anything in over 30 years. Pros or cons?
 

TFF

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Most now varnish the whole thing. Is it required is somewhat up in the air. If I remember the Stits instructions, you paint all the ply with the pink stuff. Essentially you are varnishing it with that stuff. Is it enough is up to your use.

Gluing to the ribs has been done on ULs. They get away with it because of slow speed. It’s another is it enough for your use calls.
 

proppastie

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Polyfiber recommendation:"epoxy"

Wood Surfaces Dry-sand old flaking varnish scale. You needn’t remove all the old varnish, just the loose parts. After sanding, wipe the surface with Poly-Fiber C-2210 Paint Cleaning Solvent to remove any grease and contamination. Then wipe with a clean dry rag. Now apply Poly-Fiber EV-400 Epoxy Varnish directly to the surface. Use our EV-410 Catalyst, and thin as instructed with E-500 Epoxy Reducer.
 

malte

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Usually fabric is indeed glued to the ribs. Chafing tape is used to soften sharp edges, usually found on metal structures. Having said that, you need to make sure that - on wooden ribs - you do not round off the edges of the ribs. that would reduceadhesion area and increase normal loads in the adhesion plane. Also - depending on the system used - rounded edges rely much more on cohesion than on adhesion.

Old vintage gliders are often not laced on konvex surfaces when covered with cotton (as specified in the German BVS from 1936). Only concave surfaces have been stitched, but mainly due to the process and not due to the airloads.

If you want to omit lacing, you can enlarge the rib area with appropriate wide cap strips. This is what Oratex does on the Jodel/Robin aircraft to omit stitching even within the propwash. You need to make sure, the adhesion area is large enough. Cap strips also bend a little with the airload on the fabric and thus reduce normal loads in the adhesion plane, leaving the loads more suitable for adhesive application. Cap strips can be glued to rips using epoxy glue.
 

Victor Bravo

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I would use any first aid tape that was based on a woven fabric, i.e. not "paper tape". Let it drape over the sides of the 1/4" capstrips a little, protecting that sharp edge is what the tape is there for. The old style dense cotton tape that is a little thicker is what I have seen on several airplanes. Stits or Ceconite probably have a branded product, but I'm guessing it is the same as Johnson & Johnson cotton tape.
 

Chilton

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I dont know about the german built gliders, but on De Havilland, Miles, Perceval types with wooden wings, and Auster, Piper and Taylorcraft with metal wings the manuals specify non stick tapes and prohibit gluing the fabric to the ribs.

Less of a problem with polyester fabric shrunk by heat, but with cotton or linnen fabric the shrinkage with dope will pull the ribs far enough to break them.

Unless working on an aircraft where the manufacturer calls for gluing to the ribs DO NOT STICK FABRIC TO THE RIBS.

I once had to rebuild a DH Tiger Moth wing which was broken exactly this way, it got expensive for the owner with most of the ribs broken.
 

TFF

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If you use lots of chafe tape, you are not gluing fabric to ribs. It’s just very nice sports tape that will not die because of the fabric glue. Reinforcing tape is like ribbon for dresses. Just has a strip of tape to keep it running away before it’s tied down.
 

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Chilton

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Is this the cloth anti chafe tape? Reinforcing tape on the top of the fabric.....is not that glued to the fabric? What brand anti-chafe tape do you use?
It is not specifically anti chafe tape, ceconite used to supply a heavy duty plastic tape with the STC system which is both anti chafe and will not stick to dope. I have not bought any for a while, but will have to again soon to recover my Tiger Moth.

The other non certified way is the household tape sold in Europe as Sellotape, I dont know what it would be called in the USA, but it is a shiny clear tape that the dope will not stick to to pul the rib out of line.

The tape on top of the fabric is normally refered to as finishing tape I think and covers the rib stitching, I have never heard of that being refered to as anti chafe tape, that is glued to the fabric.
 

TFF

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Anti chafe is on the structure. Reinforcing is on top of fabric but under the finishing tape. You can have too much anti chafe tape. It is a long term problem. It does not age well because it’s not part of the main system. It’s a fix. Best situation is not having to fix anything. It’s being used as a pad for a spot.

Sellotape seems to be a version of Scotchtape, maybe a little more industrial. Packing tape like. Definitely named to describe cellophane tape as a catch name, same family.
 
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