On the Chrysalis 2M that I'm building, I want to put a seperate servo at each spoiler as you recommend now.

What's the best way to route the servo and extension wire to the wing center? Maybe in a notch along the rib bottoms?

From : Don Stackhouse

I presume you have one of the older 2-meter Chrysalises, before the new Mk II. The Mk II includes oblong holes in the ribs just behind the main spar just for this purpose. They are centered vertically in the rib at that point. They are just behind the main spar because that's as close as we can conveniently get to the deepest part of the rib, and because the shear web right next to the hole can help deal with the stresses caused by the hole.

The main loads in the ribs in that area are up-and-down bending loads. In a piece of balsa in that situation, the most critical stresses are the tension and compression stresses along the top and bottom edges. Right in the middle of the height of the rib the shear stresses are greatest, but the tension and compression stresses are zero. For this reason, the middle of the rib height is the best place. Also, we wan to minimize the height of the hole, and the number of wood fibers cut by it. Since the hole needs to be about 1/8" x a little over 3/8" to allow for the connector on the servo cable (we didn't want to make beginners building this kit have to contend with cutting and resoldering servo cables and extensions), the 3/8" dimension of the hole should be horizontal.

Don Stackhouse
DJ Aerotech