Decathlon control stick slop/slack

J

John Kempton

New member
I have a 1977 8KCAB, and I assume that Citabrias and such have an identical control stick and torque tube setup.

My issue is that there is a tiny bit of movement in the stick beore it moves the controls, ie it will 'jiggle' at the top of the control coulumn.

I assume that this is caused by the bolt clearance at the stick socket/torque tube (or the connecting tube which runs beneath it) connection. I can't see any way to shim it to take out movement.

This is not noticeable when applying control inputs, but in still air cruise I can feel it and it has begun to annoy me.

Has anybody else had this issue and how did you go about fixing it? Do I just accept it as 'character' ?

Thanks

John K
 
Many years ago I had a similar problem with a 7ECA. I bought a new bolt after determining the original was worn a few thousanths. Replacing with a new bolt did not make much of a difference. I had spoken to Buzz Wagner, at the time and maybe still the Aeronca guru. In our conversations I discovered that what he called play was much more than what I considered sloppy. My 73 Decathlon has the same stick play and I believe this is typical to a point. Obviously there is an unexceptable amount of slop but I believe you would really notice it. If I grab the front and rear stick and move forward and back I probably get 1/2 inch play. I believe Buzz Wagner was talking about an inch or more.

Ken
 
Thanks Ken,
I actually have maybe 1/8" play, it has become like a pebble in the shoe annoyance.
My engineer suspected that replacing worn bolts would have the outcome you experienced, they have to have some clearance to fit through the holes and the length of the stick magnifies that.
I feel much happier after your input.

John K
 
I have an 8KCAB also and noticed the same stick play. At my last annual I had the mechaniic take the lower skin off and we took apart this control system. The design is terrible and conducive to this wear. I began thinking of ways to fix the problem by way of redesigning and fabricating a new system and then decided to just get it back in the air. The original design has a double shear aluminum casting; round tube squished flat with a hole through it; and a bolt. A more proper way would be to put rod ends on the tube and enlarge the distance between the aluminum tabs to accomodate the rod end. Maybe next year. BTW, my Decathlon has only 300 hours and this stick play has become an issue.
 
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