Bronze (oil impregnated) bushings operation

[Carlos Trigo]

Guys

In the plans (at least in XENOS’s) some Bronze oil impregnated Bushings operation is indicated (for ex. “Rotation to occur between Bushing and Plate”), and sometimes not.

It happened that, after the first installation of bushings in different parts and places, sometimes the rotation occurs where required, but sometimes not.
I know that this occurs due to the difference between the exact diameter of the holes, inside or outside.

First question: should I worry about exactly where the rotation occurs, or is it indifferent?

Second question: if it’s not indifferent, which is the practical way to achieve the correct rotation place, especially when the solution is not to ream the hole, but to fill it?

Thanks
Carlos
XENOS - B #020

[Carlos Trigo]

Nobody has an opinion on this?

[GordonTurner]

I don’t have an opinion. They seem to rotate where they rotate and as long as it’s smooth, relatively resistance free, and no wobble I just feel happy about it.

Haven’t flown yet. Haven’t had catastrophic failures in my control system. But time will tell :)

Gordon

[Rynoth]

Hi Carlos,

When I encountered this issue I ended up following the plans. I would ream out a bushing if necessary allow the bolt to move freely if it was previously binding and intended to move at the bolt. My main concern with excess rotation would be the strength/type of material that is intended to bear the friction load. For instance, if a steel bolt should rotate inside the bearing, but the bearing is also rotating within a hole in aluminum (like in the aileron bellcranks on a Sonex), I'd have an issue with that. If both parts are strong steel, I'd probably be OK with it either way (but probably second-guessing my hole diameters). Ultimately, all of my bushings do rotate as the plans specify.

[Carlos Trigo]

Thanks guys

Now I know the principle, and will be alert to all the situations where the rotation does not result as the plans indicate, or where it is not indicated in the plans.

Cheers
Carlos