Champ Elevator cable & belly fabric contact

[Eric Brown]

Gentlemen;
During installation of the elevator cables, I noticed that the cables run a bit low between the first 2 pulley groups and will contact the belly fabric. See attached photos. The yard stick locates the contact position when touching the wood stringers. This fuselage was modified by ACA to install the Citabria type elevator cable routing. My pulleys are standard MS24566-3B with 2" OD dia. and 1.5" pully grove dia. Is this a common phenomenon with the Champs ?

 

[Bartman]

Eric, yes, that area is known for this problem. In fact, as I was attaching my stringers, they were first clamped into place so I could use masking tape across the bottom of the fuselage (as a fabric simulator) to make sure the positioning of the stringers wouldn't create interference with the cables. You can cheat the stringers down a little in those mounting points to help make more clearance. With my 8KCAB project I think there is about 1/8" of space between the cables and where the fabric will be, the factory said it's normal. The cables have to be properly tensioned to keep them from touching the fabric in use.

 

[Big Ed]

Yes, common. My cables cut through my belly fabric. 3 solutions:

1. Reinforce the belly fabric with fiberglass tape or heavy fabric.

2. Install a wood spacer between the pulleys and fabric under the baggage floor.

3. Upgrade to current design spec, which includes an aluminum brace laterally across the stringer braces under the seats. Only viable when recovering.

You can go a long time with #1. Pull the seats and floorboards and glue some fiberglass or heavy Dacron tape under the cables. Eventually the cables will saw thru that too, but you should get at least a few years out of it. If doing yourself, this is a cost effective approach.

If you want a more permanent fix and recovering is not in the cards, contact ACA about the spacer. They have a kit, but you can talk them into sharing the drawing and make your own pretty easily. It's just a couple of wood strips glued together.

You can somewhat do #1 and #2 with the seats and seating floorboards removed, but pulling the baggage floor will allow you to do the job more thoroughly. That can be done but it is tricky, so try with the baggage floor in first.

 

[Bartman]

@Eric Brown are those new stringers and are they from ACA? If so, I'd give them a call. They have just about everything pretty well dialed in and they should be able to explain your options to you if you're not happy with how it's all laying out.

 

[Bob Turner]

Some Decathlons have aluminum cross-members in that general area. They fail routinely due to prop-induced vibration, as does the fabric adjacent.
We wound up reinforcing a set with extra aluminum, and sewing the fabric patch to the old fabric. I think it survived after that.
My 180 Dec does not have the transverse pieces. I have had fabric failures in the vicinity, but it has never been a big deal. I think the folks who recovered my bird in 1992 extended the stringers to avoid the cable problem.

 

[Bartman]

The crossmembers are forward of the area in Eric's photos, under the seats, more mid cabin

 

[Eric Brown]

Gentlemen;

Thank you for your input. My semi-solution was to extend the RH stringer to a newly brazed on clip and add additional material to the bottom of the aft center stringer. This now gives me about 1/4" cable fabric clearance in the affected area. Yes the stringers were ACA supplied and I had already installed aluminum cross members under the aft seat area. See attached photos. Check out my latest thread about throttle / carb ht levers.