DOH! thanks Bruce. Yes, the SERVOs go out in the wing pannels. Ideally at about mid-aileron. But it's not really critical, esp for a trainer.

If you use micros, be sure to use metal gears. Nylon gears in a micro case won't be strong enough to withstand the forces on even a single aileron and will strip.

And no, I wouldn't use 20in/oz servos, I'd use at least something in the 35-40 range. Technically you might not need it, but the size of the various servos I've seen work out that going smaller than a Hitec HS-81 is going to be too small for the beating the servo will take from the size and speed of a .40 size glow trainer.