minimum pushrod threads

What's the minimum number of threads that the eyebolts should be inserted for the pushrods between the control stick and (1) the ailerons and (2) the elevator?

More than half. Since it isn't a turnbuckle style, one of the failure modes is that the pushrod unscrews itself all the way to one end of the threads. Having more than half the threads engaged on each end means that if this happens it won't unscrew completely from the other side. I had to remake my aileron pushrods because the lengths on my drawings were too short (and different) than what Vans had on their copy of the drawings.

Control rods

Ross7A-builder said:

What's the minimum number of threads that the eyebolts should be inserted for the pushrods between the control stick and (1) the ailerons and (2) the elevator?

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Typically the assembled rod is rotated as far as it will turn clockwise or counter clockwise. The rod at the unscrewed end should not fall off. It's inurance in case a pinch nut is loose the control rod cannot fall off.

Quick responses and makes sense. Thx!

Belt and suspenders

A technique is to use two jam nuts. Put two jam nuts on each end, set the length and torque the first jam and the tighten the second nut against the first.

The aileron bell crank to pushrod assembly has witness holes so make sure you can see threads.

If you look at the female threads, there should be a witness hole in the threaded area. That is the minimum engagement for the male threads. You can poke some safety wire in to check.

Dave

If your push tube is a little short you can use the rod end bearing that has a longer threaded shank. I think this only helps you within a half inch of where you want to be, but that may be enough. Those longer bearings are available at Vans and Spruce. Check out the Aurora bearings. Heims are much more expensive. My spare bearings drawer has a few possible choices, depending on size. Some are Heims. I like beer, especially Spotted Cow. A new bearing might not be worth that much, depending on what bearing you need. My Spotted Cow run is 1+30 each way.