Staples for wing rib fabric attachment?

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Malcolm C

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I have just fabric covered my Flea wings and for better or worse have not rib stitched the wings. I was pondering the situation and wondered whether you could use short stainless staples to augment the glued joint? Even on the flimsy Flea ribs which are 1/4" cap strip construction you could put a staple wherever an upright or diagonal intersected the upper or lower cap strip. A good idea or a futile exercise? I welcome your opinion please, thanks in advance .Malcolm
 

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TFF

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I would not want to possibly split the ribs that late in the game with a staple, and I would worry about tearing the fabric in flight. I guess you didn’t glue the fabric to each rib? Personally I would be stitching, taping, and painting. I went with a friend that owns an Ercoupe with fabric covered wings. You can see the fabric pulling on the stitching in flight.
 

wsimpso1

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Hmm, two issues to perhaps check:

How much load does it take to start staples out of the rib? How much load per chordal inch does that equate to?

How much load does the rib stitching support per chordal inch?

The thinking should be to compare the forces that stitching and stapling will support. Maybe check the energy of lifting the staple vs energy to lift the stitching.

Hmm. I am concerned that staples will lift and strain the adhesive at lower loads than the stitching will. The concern is both immediatly and after the structure has aged - wood drying out, absorbing moisture, staples becoming oxidized, etc.

Billski
 

Malcolm C

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I did glue the fabric to the ribs and added a tape strip above and under each rib. It will be operated under FAR 103 so max speed around 65. I tried the staples on some spare ribs and as each intersection has a coupon either side of 1/16 ply I have not managed to split one yet. I did not get around to seeing what force would pull out the staples but using them as temporary fasteners on blind glued areas I have had to use quite a lot of force to remove them ,of course as the airframe ages it might change.
The staples are stainless steel so they should be fairly corrosion resistant .
Both Henri Mignet and Chris Falconer are long dead so no help there, thanks for your input gentlemen I will stick with the glue and forgo the staples, it was just a thought that I had......
 

proppastie

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The glue has a peal and shear strength. .make 1 inch wide tests on 1/4 wood then compare to the calculated forces/loads on the fabric on the rib....
For example these people claim one doesn't have to ribstich with their system. ......I would like to find someone who has used their system.
 
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Dana

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When I redid the rib stitching on my Fisher 404 I sewed right through the finished fabric, then covered each with a dollar patch.
 

Riggerrob

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Staples would have been most valuable if you used them as temporary clamps immediately after you glued fabric to rib cap strips.
 

Ava

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When I redid the rib stitching on my Fisher 404 I sewed right through the finished fabric, then covered each with a dollar patch.
The guys basically did the same on Ole Piet's initial cover (undercurved FC-10 airfoil). But used a strip of pinked tape per rib.
 

Dana

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The guys basically did the same on Ole Piet's initial cover (undercurved FC-10 airfoil). But used a strip of pinked tape per rib.
Pinked tape (finishing tape) is standard and was already on my wings, but I re-ribstitched through the original tape, followed by the patches.
 

PTAirco

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Why are people so adamant to avoid rib stitching? Especially on something as small as a Flea. It would add a couple of days to the construction time at most. But people will do anything to avoid it. Rib stitching is something that evolved because it was necessary, not because it as something optional. People have died because of fabric separating from the ribs. It's a dirt simple, easy thing to do, so just do it. I'd hate to fly in airplane and constantly think " I wonder if those staples are holding..." .
 

Malcolm C

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If it were a general aviation aircraft I would agree with you but it's an ultralight Flea with a max speed of 65 and I will probably never exceed about 55 in it. Lots of ultralights do not rib stitch as the speed is so low. I will keep an eye on the fabric especially on the top of the wings and if I see any signs of the glued joint separating then out will come the needle and thread, thanks for your opinion even if I disagree with it.
 

Skippydiesel

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Maaaate; Just glue. No stitching, no staples soooo easy. - I used the Stewart System fabric & glue. Get the fabric as tight as you can THEN iron, as per the instructions, for a drum tight finish. For added security overlap (on under side for aesthetics') the fabric by about 100 mm.

My aircraft good for 120 knots and no sign of seperation/lifting.
 

Mr.Bill

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Malcolm, if you want to know about installing fabric without rib stitching, I recommend a good read - AC 43.13-1 section 2 paragraph 2-8 "the blanket method". Since the blanket method is accepted by the FAA for use on certified aircraft, I see no reason that it would be unacceptable for ultralight aircraft. Just make sure you follow the instructions, including those pertaining to maximum speeds such as do not dope a seam on the leading edge if the VNE exceeds 150 MPH, and you should not have any issues.
 

Dana

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Malcolm, if you want to know about installing fabric without rib stitching, I recommend a good read - AC 43.13-1 section 2 paragraph 2-8 "the blanket method". Since the blanket method is accepted by the FAA for use on certified aircraft, I see no reason that it would be unacceptable for ultralight aircraft. Just make sure you follow the instructions, including those pertaining to maximum speeds such as do not dope a seam on the leading edge if the VNE exceeds 150 MPH, and you should not have any issues.
The blanket method isn't in lieu of rib stitching; it's an alternative to a sewn envelope. Rib stitching is still required.
 

Dan Thomas

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Fabric separation could be a rapid-progress phenomenon. If it starts to lift, the turbulence will start it flapping and that will rip the whole works off real quick. It has happened.

The glued-down stuff I saw had really wide rib capstrips to spread the load on the adhesive. Seems to me that 1/4" wide ribs should be stitched. Staples would add more problems than solutions. You'd be relying on friction alone to hold that fabric down, and as the wood ages, along with corrosion of the staple and the rot that the corrosion introduces, that disappears.

One can't rely on fabric tension to help. The suction forces just aft of the leading edge are phenomenal.

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bmcj

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Wait, are you talking about stapling the fabric to the top of the rib, or stapling the side of the rib so that you bridge the glue joint between the upright and cap strip?
 
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Aesquire

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I would not staple through fabric into ribs instead of stitching. That's a LOT of Crack propagation possibilities for the wood & rip points for the fabric. No upside that I see.

And I point out that I've seen tarps ripped to shreds at under mile a minute speeds on trailers and car roofs. That's a loose spot that spreads, different from doped fabric but ....
 
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