I have 3 servo mounting areas. 1 area to fit 3 servos, and 2 spots in the wing that is on a skinny piece of wood that is for my flaps. In the pictures, do these look strong enough. Also Where the motor mount comes in cotact with the hard wood, the piece supporting that is balsa, will that be strongenough for a Y.S. F-1.20.

Thanks, Dave Trimmer

Looks pretty typical to me. You could put a support piece on the flap servo brackets if you feel the need.

my p47 has the same mounts for the flaps and alerons in the wing, those are plenty strong after you install the hold down screws

You could also fiberglass the whole inside of the firewall. That would help with the vibration.

Thanks for your help.

if the firewall is only glued onto balsa, then i don't think it's strong enough. a 120 will pull that clean off. i'd rather not take the risk. the firewall should be of at least light ply.

the servo mounts, however should be okay as long as your screws screw through hardwood or ply. a 120 size shouldn't have anything mounted to only balsa. my two cents.