ACA Factory Fuselage Fabric Assembly

Bartman

Bartman

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Finally moved on to the side/upper fabric for the fuselage today. It can be bought from the factory as a single assembly with the two pieces sewn down the middle. The seam is necessary since there isn't a structural member in the middle for the fabric to attach to so the sewn seam is considered "structural" serving to hold the two panels together aided by a reinforcing tape.

You start by laying the fabric onto the fuselage so the upslope in the seam fits at the base of the fin. The fabric is cut for a Scout so there is a lot of extra at the top of the fin due to the Scout having a taller vertical stabilizer than the Citabria/Decathlon aircraft. The goal, according to the factory's fabric guru Adam is to keep the seam centered on the leading edge of the fin as far down as you can and to then have it centered by the rear of the cabin.

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If you're trying to get the fabric to lay out correctly and it won't, you have probably not pulled the seam far enough up the leading edge of the fin.

Once you think it's in place and laying out as well as it is going to, you have to summons the bravery to start cutting holes in it. The horizontal stab tubes have to be cut first.
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Once those holes are cut, center the seam on the leading edge of the fin and start working the fabric into position. Use a lot of clamps to hold the seam in place on the leading edge of the fin as it isn't glued there and it has to stay centered as you iron the slack out of the fabric, alternating sides to keep the seam from pulling to one side or the other.

I probably went to the hangar and laid out the fabric at least six times before finally pre-gluing everything and getting started. I was happy with the fabric laying out as shown in the photos.
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As I began to tack the fabric into place with the iron I was able to keep pulling and adjusting the lay of it so it came out tighter than it first looked.
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Part of my strategy is going to be to cut open the windows and use the freedom to pull fabric into the openings to remove any slack I can before gluing the fabric to the window frames. I'm happy with it so far, those big side areas will shrink a lot once the iron gets on there so I think it's going to be ok.

This was the beginning of one of the less successful attempts!
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Will post more pics as I go.
 
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Have you already done the bottom? I started there so all my seams or overlaps would allow rain to drip down. Hope this makes sense.
 
Go for it it will shrink more than you think on mine I had to cut the stitching up the tail as I felt there was to much material. Make sure everything is in place like trim cables ground wire and so on.
Good luck I’m sure it’ll come out fine.
 
Bart, curious if you think doing the belly in heavy duty fabric (Ceconite 101) would be viable? Would the different fabric weights cause issues when shrunk, such as with one pulling the other off line? Seems to me since both are glued to the lower longerons, that would not be an issue.
 
Another thing some where some one reinforced where the cables might rub the belly I thought that was a good idea but mine was assembled when I saw that.
 
Bruce said:
Go for it it will shrink more than you think on mine I had to cut the stitching up the tail as I felt there was to much material. Make sure everything is in place like trim cables ground wire and so on.
Good luck I’m sure it’ll come out fine.
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Bruce,
I'm actually late getting this done because I had a long list of stuff to finish before putting the fabric on and it took me forever to complete the list! I was a little chicken about the fabric but more late finally getting everything into place.
 
Big Ed said:
Bart, curious if you think doing the belly in heavy duty fabric (Ceconite 101) would be viable? Would the different fabric weights cause issues when shrunk, such as with one pulling the other off line? Seems to me since both are glued to the lower longerons, that would not be an issue.
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I don't think it would be a problem. for what it's worth, i don't think it's the fabric that is the problem as much as it's the tapes and the tendency to put les paint on the belly. and smoke oil residue, not good for belly fabric but i don't think heavier fabric would address the problems going on under there as much as better paint coverage and really good tape adhesion would. in fact, I plan to to 2" tape on the center stringer with an overlay of 3" tape just because it's such a problem area and even that might be overkill. not sure
 
Cables sawed thru my old belly. May or may not be a problem depending on geometry of your belly stringers, which can vary by aircraft. Factory solution is a plywood bracket to push the belly fabric down under the battery compartment area. I'm trying to get drawings for that, because I need it for mine. Factory says they don't install it for new ones, so presumably the stringer brackets are a bit longer.
 
I didn't have a lot of clearance so I tried to cheat a bit when positioning the stringers and drilling the mounting holes. There's about an eighth of an inch separating the cables from the fabric. I used masking tape to simulate the position of the fabric when planning the stringers.

Clamped the stringers in place, put masking tape across them, pulled the cables tight to see how it all laid out. Over and over again! lol
 
Bartman said:
I didn't have a lot of clearance so I tried to cheat a bit when positioning the stringers and drilling the mounting holes. There's about an eighth of an inch separating the cables from the fabric. I used masking tape to simulate the position of the fabric when planning the stringers.

Clamped the stringers in place, put masking tape across them, pulled the cables tight to see how it all laid out. Over and over again! lol
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I didn't check until after I mounted the stringers. Running a straight edge across the stringers made it clear I will have a few inches of contact between cables and fabric under the battery area. At this point, I don't think re-mounting the stringers is an option, so am trying to get the pattern for the bracket. Had it before but misplaced it.
 
Bart, be sure you don't remove all the slack from the fabric...a good shrink @350° will tighten the fabric nicely with a 10% shrink (you lose 6" in a 60" run). If you pull the fabric tight and then try and shrink it you will get stringers that bow in and deform as well as seams that pull loose. Just get the big wrinkles out before you start shrinking. Ditto with the clamps on the vertical stab...you have to allow the fabric to stretch between the clamps or you'll get puckers in the fabric. A clamp every 6-8" will be sufficient.

Chris
 
Bartman said:
Thanks Chris! I'll do that. i was going to unclamp the leading edge and iron it after everything else was tight
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Bart,
Actually you tighten up the vertical stab fabric along with the fuselage covering...
Straighten the seam on the front of the vert stab and clamp in a couple of places to keep it from sliding around. Glue the fabric to the top of the vertical fin. Glue fabric to the back vertical fin tubing. Pull out the slack and glue to the lower longerons. Continue forward and glue at the windows, etc. When the entire perimeter is glued you're ready to iron...Then when you shrink the fin/fuselage fabric all at one time the transition from the fuselage top to the sides will be nice and straight. Take your time and shrink both sides a bit at a time to keep your sewn seam straight on the vertical fin. As you have cut holes for the horizontal stabilizer pegs you'll want to glue a reinforcing patch around each hole before you try to shrink it or when you shrink the fabric those holes will end up being 6" in diameter!

Chris
 
Chris,
That's what I was planning to do except I was going to leave the leading edge of the fin clamped and iron it from side to side as the clamps are coming off.

About the patch, I've been under the impression all patches and tapes get put on after ironing?
 
Hiperbiper said:
Bart,
Actually you tighten up the vertical stab fabric along with the fuselage covering...
Straighten the seam on the front of the vert stab and clamp in a couple of places to keep it from sliding around. Glue the fabric to the top of the vertical fin. Glue fabric to the back vertical fin tubing. Pull out the slack and glue to the lower longerons. Continue forward and glue at the windows, etc. When the entire perimeter is glued you're ready to iron...Then when you shrink the fin/fuselage fabric all at one time the transition from the fuselage top to the sides will be nice and straight. Take your time and shrink both sides a bit at a time to keep your sewn seam straight on the vertical fin. As you have cut holes for the horizontal stabilizer pegs you'll want to glue a reinforcing patch around each hole before you try to shrink it or when you shrink the fabric those holes will end up being 6" in diameter!

Chris
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On the H stab pegs, could you leave the fabric uncut, do an initial shrink to get the position located, then cut the hole and final shrink to taut?
 
they stick out too far and make pulling the fabric towards the tail post impossible.

edit. on the other hand, i'm doing this for the first time so i don't know, maybe it's possible. it didn't appear to be an option as i was laying out the fabric
 
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Big Ed said:
On the H stab pegs, could you leave the fabric uncut, do an initial shrink to get the position located, then cut the hole and final shrink to taut?
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That's the way. The fabric won't pop...it's tough as heck. You can do a shrink to 275• or so to get close and then cut the slit in the fabric and force the pegs through then iron the fabric everywhere except in a 12" circle around the holes. Then after you put a reinforcing patch around it you touch it up with a small iron.
But as Bart has holes already I would put on a patch and keep the iron away from the holes all together. The fabric will be tight around the patch so you'll never see any difference. If you have some spare fabric you can tack it down and make a small slit in it...then heat it like you were shrinking the cover. The results are amazing! It would be a very unwelcome surprise on your cover job!
As to keeping the vertical fin seam straight you're right on target...shrink one side a bit then the other as needed to keep the seam straight!
This lefty-righty thing is necessary on the rear of the fuselage too to keep the sewn seam straighton top of the fuselage so you will be able to have a nice straight reinforcing tape..iron a place on the fuselage side then go to the same place on the other side and iron there. Alternate sides everywhere along the fuselage. I always started ironing at the bottom longerons and worked my way up to the fuse top...that way you can watch the center seam closely and use your iron to "tweek" the seam from side to side as you end up on top of the fuselage!
It sounds more complicated than it is and once you see how you can use your iron to move the fabric around you'll catch on easily.
Chris
 
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