R, Then say "yes" to a suspended bell crank, and 'splain how to do it 
I can't say how to do it in a foam wing, but I've seen pictures that make lots of sense.
Here's how you pretty much have to do it, in any wing:
- Install the bellcrank on a rod or bolt, so that the bellcrank is held in the center of the pivot. Lots of people use rods. So far, I've been using #8 bolts to good effect. I use bolt with a long smooth shank, with spacers to hold the bellcrank where I want it on the smooth shank. Lots of people who fly lots better than me use rods -- take that as you may.
- Install plywood (or aluminum, or titanium, or carbon fiber -- really, this is up to you) plates top and bottom that catch the spars, and that can hold the pivot in place.
- When it comes time to install your control system, put the bellcrank in place, shove the pivot through it (and through any spacing devices you may have -- devised), and fix everything into place
Once you have the bellcrank centered in the wing on a pivot, and the pivot firmly held in the wing, everything else is details. Have you tried digging through the various build threads to see how other people do it?
Topic: floating bellcrank (Read 1754 times)