B-Model Aileron Pushrod Interference at Stick

[Spaceman]

Howdy gents,

I'm rigging my ailerons, and I have the neutral position set right where I want it, BUT I have found that once I tighten all the jam nuts on the long pushrods, the rod end bearings will run out of room to swivel and then interfere with the stick where they're mounted (in the area of the pic below).

stick.JPG (66.37 KiB) Viewed 3725 times

I initially tightened all the jam nuts with the stick forward, and then I noticed the ailerons can't be moved with the stick held aft. Then I loosened all the jam nuts, strapped the stick all the way aft with the seat belts, tightened them again, and now the ailerons can't move with the stick forward! I can't seem to find a middle ground where they can move freely throughout the stick's fore-aft range. Has anyone else run into this?

[Spaceman]

Is it ever acceptable to use a jam nut on only one end of a pushrod? I'm thinking probably not, but if I leave one loose then the rod end bearing can swivel just enough to not bind up......

I just had another thought, maybe I can add a washer or two between the outboard rod end bearing and the bell crank to buy a little more room to rotate on that end. Maybe that would be enough for the inboard end to not bind inside the stick assembly. I'll try it later!

[Spaceman]

Dang my extra washer idea didn't help at all! I'll have to think of something else...

Edit: actually, I think it's the fender washers on the outboard end that are the limiting factor. Maybe I can dish those washers out and maybe use an extra washer or two and longer bolts

[Bryan Cotton]

Maybe I can dish those washers out and maybe use an extra washer or two and longer bolts

I've dished my fender washers before. I'll see if I can find my writeup. You won't need extra washers or longer bolts.

[Area 51%]

I too had fender washer clearance issues, but lacked the talent of Bryan to manufacture dished washers. I did come up with a "stepped" washer (for lack of a better term). I'm sure I was enlightened by someone on this site. I have no idea where I got them from, but the part number is 3068-03 and the description is 3/16 inch Rod End Retaining Washer.

I can email you a picture of the bag and the washers if you like.

[Spaceman]

I had to dish a couple washers on the mixer that were messing up my elevator travel. I found some concave jewelry making die that my wife had in her craft pile that worked great with a ball peen hammer. That was a couple years ago though and we've moved since then so I hope I can find it again!!

I just redid all the aileron rigging and now it's working well WITHOUT the fender washers installed, so they were definitely the issue. I think if the dish method works I'll still be good and be able to retain that safety factor. Now to go back home and smash some washers

[Spaceman]

I too had fender washer clearance issues, but lacked the talent of Bryan to manufacture dished washers. I did come up with a "stepped" washer (for lack of a better term). I'm sure I was enlightened by someone on this site. I have no idea where I got them from, but the part number is 3068-03 and the description is 3/16 inch Rod End Retaining Washer.

I can email you a picture of the bag and the washers if you like.

Ah yeah, I've seen those on race cars. If I can't make them myself then I guess I order a few of those. I just don't want to wait for shipping!!

[Bryan Cotton]

Here is my solution. I bolted a few standard washers to either side of the fender washer. I then got a socket just slightly bigger on the OD than the fender washer. I pressed on the bolt and cupped the washer. No more interference but the washer will still retain a failed rod end.

cupped washer.png (389.48 KiB) Viewed 3627 times

[Spaceman]

Yup the dished washers fixed it! That, and tightening the outboard jam nuts on the big pushrod first, so I could make sure nothing was binding at the stick when I tightened the inboard jam nuts.