I was hoping to do something a little smoother like having the aileron torque tube rotate in a needle bearing.
Ollie,
Ambitious project! You did not say where you are from nor which set of ultralight rules you are living with. There is a big difference - US rules are 252 lb airframe weight, Euro rules are much more substantial birds.
The designs of Steve Wittman (airplanes in the Smithsonian among others) used torque tube actuation, no needle bearings, and my plans for Steve's Buttercup seem to indicate tube in tube, just like his tailfeathers and in other designs mentioned above.
You can see similar schemes in
, wing starts around 60 seconds in. You can see a lot of details of his pretty little airplane here. Do not let his modesty fool you, he has built and flown a bunch of airplanes...
Common designs even in much heavier airplanes are tube in tube, bolt in tube, short lengths of extruded piano hinge, Oilite bronze bushings on bolts, and self-aligning bearings. All rely upon a bit of lube as they are all sliding friction, not a rolling element bearing in the bunch. Given the low forces and very low sliding velocities for an ultralight, rolling element bearings add useless weight, cost, and build complexity.
Billski