Rudder cable attachment question

[cbnank]

I am attaching the rudder cables to the elevator horn. The Standard Aircraft handbook states that when using castillated nuts (for cotter pins) you should torque to normal tolorences, and you are permitted to back up one notch when you insert cotter pin. (Or something similiar since I do not have the book with me right now.)

That does not seem logical for these type attachments. I think the nut should be just tight enough so everything can freely move.

I also have the same problem with my control stick mechanisims that are supposed to move freely.

Can anyone help on this?

Thanks,

[scard]

You are correct. You can't torque the rudder cable attach bolts.

[szicree]

Originally Posted by cbnank

I also have the same problem with my control stick mechanisims that are supposed to move freely.

Can anyone help on this?

Thanks,

Pretty sure all the control stick attachments have bearings and should be tightened down.

[N908RV]

Carl,

Scott and Steve are both correct. With your rudder, you should just snug it down so there is as little slop as possible, but it should freewheel around with no resistance at all.

The pushrod controls all have bearings and you should be torquing those down to spec. If they are too tight, you may have to back off just a little. This is not so much of an issue with standard rod end bearings, but it can be an issue of you monkey on the sticks with their sleeved bearings. The bearings should be just a fraction longer than the bushing in the stick so as to allow free movement once the bolt is torqued down.

[gstone]

Are you really going to hook the rudder cables to the elevator horn?!?!?!?!
Sorry, had to ask
greg

[jsharkey]

Originally Posted by cbnank

I am attaching the rudder cables to the elevator horn. The Standard Aircraft handbook states that when using castillated nuts (for cotter pins) you should torque to normal tolorences, and you are permitted to back up one notch when you insert cotter pin. (Or something similiar since I do not have the book with me right now.)

That does not seem logical for these type attachments. I think the nut should be just tight enough so everything can freely move.

I also have the same problem with my control stick mechanisims that are supposed to move freely.

Can anyone help on this?

Thanks,

The main left/right pivot bearings on the stick assembly are plain bushings and need to be free enought to rotate so the castle nut doesn't need to be torqued down - just snug. The spherical bearings should be torqued and I believe use lock nuts - however I seem to remember a post where they came lose so it might be a good idea to use cotter pinned castle nuts here too.
Jim Sharkey

[sportpilot]

The way we learned to use castle nuts is tighten them to their snug fit, then crank in just enough more to make the cotter pin hole line up to the next slot..

[Jekyll]

Originally Posted by sportpilot

The way we learned to use castle nuts is tighten them to their snug fit, then crank in just enough more to make the cotter pin hole line up to the next slot..

Well, something was lost in the translation then. This is why we have minimum and maximum torque values on nuts. If they were all self locking, there would just be 1 standard torque for each size and thread type.

The correct way, in general, for castellated nuts is to torque to the minimum specified torque value and see if the castellations line up with the hole. If not, you may turn it in the direction of tightening until you line up the holes or reach the maximum torque value, which ever occurs first. This is an absolute maximum value for the hardware. If the holes can't be aligned someplace between the minimum and maximum torque values, remove the nut, re-clock the threads or add a thin washer if the stack up can accept it, then repeat the process until you are successful.

As to the control bolts, if the part must move, then mobility takes precedence over the standard torque values and you torque it only enough to not impede the movement. Generally in more documented aircraft, the publications would specify a special torque for those type of installations. This would be one that ensures the assembly stays together while the parts move as required.

Thought it necessary to correct the record because torquing correctly is important.

Jekyll