Citabria Aileron cable fittings scraping against internal covers

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kubark42

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During one of the first preflights, we noticed that there was a scraping sound coming from the interior trim covers mounted at the rear side of the doorframe/windowframe (depending on if looking at left or right side of plane). We took the panel off and saw that the scraping was coming from the cables' connection fittings.

I believe it's the same problem as https://www.americanchampionaircraf...ions/scraping-sound-during-aileron-deflection

This doesn't look like it's a safety problem, as the scraping is very mild and for sure the trim plate will wear through long before the fitting does. Still, it'd be nice to resolve it forever.

It didn't look like there was any super-easy way to address the problem, short of adding spacers so the trim plate had a little more clearance. Before we go this route, any other ideas? Or should we just ignore it as one of those "if it ain't broke" moments?
 
I have the same thing going on. The scraping is coming from the aileron cable rubbing on the side cover in front of the right rear window. Any ideas on the fix for this? Maybe putting some tape on the inside of the trim piece so there is not metal rubbing on metal? I see the two screws on this piece but, what else holds this piece of trim in place?
 
On a 7AC and earlier models it's just a simple aluminum cover held by a few screws. Your plane may have some kind of upholstery on it to remove too. Underneath the cover is a turnbuckle connecting the cable from the wing and the cable coming up from aileron sector belcrank under the floor.
That turnbuckle connection is doing rubbing.
 
Thanks Champdriver. Did you do anything to eliminate the rubbing or choose to live with it? I seriously doubt it will ever cause a problem and the only time I hear it is during the preflight when the engine is not running. So.......
 
weleonard said:
Thanks Champdriver. Did you do anything to eliminate the rubbing or choose to live with it? I seriously doubt it will ever cause a problem and the only time I hear it is during the preflight when the engine is not running. So.......
Click to expand...

Do not accept critical control cables rubbing like that

Many jobs/years back we had a similar issue in a super cub, one of our pilots was luckily able to land it after the aileron cable gave way

it’s not something to accept and be wary of anyone who says it’s “ok”
 
The only thing I'd add to what's already been said is that just below the floor on each side is a bellcrank that the aileron cables connect to. From the center torque tube that the sticks are attached to, there are two metal straps on each side that connect the torque tube to the aileron bellcranks. If one of those bellcranks were to come loose, or crack, or if the bearing/bushing failed, it might change the position of the aileron cable under that flimsy aluminum cove and cause it to rub. So, if the noise is there and you haven't investigated why it's rubbing, it might be worh a look under the floorboards. While you're there, maybe change out some of the control components that wear with time introducing slop to the controls. The stick-to-stick connecter that is inside the torque tube is a biggy for making slop in the pitch controls.
 
Well, it looked sort of complicated to completely remove the side trim piece. Also, short of starting to bend it and hoping for the best, I'm not sure what I'd do even if I removed that piece of trim. So, this is what I came up with and it solved the problem. I might do something different later if I come up with a better plan. Pic1 shows where I wedged a piece of plexiglass (wrapped in tape) inside the window top trim and extended it behind the side trim forcing it away from the rubbing cable.

Pic 2 shows the left side of the aircraft where the upper window trim is a little longer and already extends behind the side trim. If this were done on the right side, it might have prevented the rubbing issue.
 

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Kubark, Welenard,

Many times the fabric from covering the fuselage does not get cut out correctly in alignment with the cable route. The cable then rubs on the edge of the fabric going back and forth making quite a racket. You will need to take the wing root covers off to confirm this. You can also access the aileron carry through cable in the over head just above the rear seat. If you have a normal head liner there should be a zipper there to unzip and have a look as someone on the outside moves your ailerons slowly back and forth. Also you should be able to see the phenolic guides held together by two small bolts and nuts where the aileron cable slides inside of and helps maintain alignment, these are just on the outside of the fabric mounted on a small metal tab. If those are worn or loose that can also cause noise. While you are at it inspect your aileron cable pulley for condition at the same location. Reposition your pulley by rotating a quarter turn as this evens out wear and also look to make sure a cotter pin is installed just above that pulley. Found many with no cotter pin. The cotter pin acts as a aileron cable pulley retainer keeping it from coming out of the pulley track.

As to installing anything tapped or loosely attached inside a aileron cable track, inside those covers, is just asking for trouble. If it comes loose where is it going? Maybe into the lower cable track where it connects the the lower bell crank or worse yet up into the pulley. Bad idea! Pull the covers inspect the cable for issues and see where it is rubbing on the inside of the cover. If you have never pulled those metal cover's before it's bit of a explanation as to how to do it. They are not fun coming off or going on. You should really have someone show you if there is anyone available. If you are anywhere near Rainbow Ron in Moses Lake call him then fly over there after you pulled that plexi glass piece out. He can show you how to pull those covers.

Cheers, Brian
 
kubark42 said:
During one of the first preflights, we noticed that there was a scraping sound coming from the interior trim covers mounted at the rear side of the doorframe/windowframe (depending on if looking at left or right side of plane). We took the panel off and saw that the scraping was coming from the cables' connection fittings.

I believe it's the same problem as https://www.americanchampionaircraf...ions/scraping-sound-during-aileron-deflection

This doesn't look like it's a safety problem, as the scraping is very mild and for sure the trim plate will wear through long before the fitting does. Still, it'd be nice to resolve it forever.

It didn't look like there was any super-easy way to address the problem, short of adding spacers so the trim plate had a little more clearance. Before we go this route, any other ideas? Or should we just ignore it as one of those "if it ain't broke" moments?
Click to expand...

in re-reading your original post, those covers are pretty flimsy, have you tried twisting them a bit to open them up where the rubbing was happening? Twisting might not do it, you have to just flex them to get them to lay in place better so there's no rubbing. They're easily influenced, it shouldn't take much.
 
I think your right Bartman. I can feel where the cable is rubbing if I rest my hand on the outside of the cover. It's barely touching the inside and, if I pry the top of the cover out less than 1/8 inch, the cables move without rubbing. I'm thinking my back-seater may have used that cover for a hand hold once or twice and tweaked it a bit (I'll be discussing that with her).

Thanks for the advice, Slipon. I've removed my piece of plexiglass. It was mostly wedged in above the window with just a bit of it wedged under the cable cover to pull it out, but I was not crazy about that solution either.
 
Bart,

As to your comment about butting in to the conversation. Many times it's been good you did to keep us all coloring inside the lines here. Too easy for me to get off topic sometimes.

Cheers, Brian
 
Without removing it, I was able to "flex" the cover in the opposite direction of the flex that would have been put on it if the back-seater were using it as a handle to assist in sitting up or getting out of the rear seat. The result....no more rubbing. I appreciate all the comments and assistance.
 
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