Control Stick Pushrod

B

Bill Cumberland

Member
I have just about finished my fuselage and i am wondering about the pushrod from the control stick to the idler arm. The end at the stick is fixed and the end at the idler has a rod end on it but the amount of swivel on the rod end is not enough for the movement in the stick. Should the rod end be allowed to swivel in the threaded bushing that holds the rod end. I always thought there was suppose to be a locknut on the rod end to eliminate thread fatuiqe through vibration. Thanks for any help
 
I dont understand Bill, the rod end is placed inside the fork of the idler and is clamped tight with a bolt and nylock nut. This allos the spearical bearing to turn. Is the rod end hitting the idler or something? Looks like there should be plenty of room and clearance. What threaded bushing, by the way. I dont see one.
 
I made a threaded bushing on the lathe and fishmouth and roset welded in by pushrod for the rod end. Once the rod end is clamped tight in the idler the rod end does swivel but i do not think enough The edges of the rod bearing hit the idler and on the plans that shows the idler it shows the pushrod going to the elevator with a locknut and the one going to the control stick without one that made me think that the rod end should swivel in the nut or bushing however you made your pushrod Thanks
 
Gentlemen,
Just this morning, I came upon the issue described above. The bearing does swivel, in the idler assy, but not enough to allow much lateral stick movement. I figured I'd stir the subject up, since I don't see an agreed upon resolution. Are we to allow the bearing to swivel in the threads? Or what?

Bill
 
When building my LSA, I asked Bob this question and he said they leave the lock nut off the front rod end bearing where it threads into the end of the push rod. ( i.e. the rod bearing that connects the bottom of the pivot arm to the pushrod connected to the rear stck) He keeps the threads lubricated to provide the additional angular movement needed.

That said, I was judging the extra movement required without the ailerons connected so full possible stick travel. Perhaps the travel isn't as great when the control surfaces are connected.
 
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There is a smaller rod end available that has a narrower body and a shorter threaded shank but is the same shank diameter and center ball hole. It allows for a bit more swivel before the rod body contacts the ears of the idler arm. Can't remember but u may have to shim the ball width. Personally don't care for the no lock nut idea. I don't have the part number as I am away working the summer. Let me know if that works.
 
I recall responding to this problem. I seem to remember the solution was spreading out the arms a little with a joggle on each side of the "arms" that capture the rod end bearing, and then adding a washer on each side. But that is what I seem to remember. Mark
 
FYI, I just applied Mark's "recollection" to my LSA(joggled out the lower .75" of each arm , 1/8" per side, opening now .75" instead of the "snug fit on the rod end width" of .5" with two "thick" AN washers per side to take up the space between the rod end and the arms.

Now appears to have full side to side stick travel with the lock nut installed on the rod end so it no longer rotates in the pushrod.
 
A heartfelt thanks to all! Sounds like a reasonable solution that I like a lot better than leaving the locknut off. I may even have the narrower rod end that Steve described.

Bill
 
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Mark is correct. Used this method on mine. The upper spread on the idler is around .510", the bottom is .610" approximately. The stick side to side seems to be enough, but I haven't hooked up the aileron cable yet.
 

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I didn't like the "loose" rod end (without the nut) either. I first tried spreading the idler and adding washers on each side, but found the rod end housing would contact the washers. My solution was to use bushings (1/4" X .028) in place of the washers. Plenty of clearance this way.
 
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