CG on the Cermark Sukhoi is on the spar, the thickest part of the wing, or thereabouts. I actually have mine a bit aft of that, but (if you're ready to fly one of these) you'll choose your own CG.

Throw away the plastic/screw horns for elevator & rudder, they'll break. Use Du-Bro which have the screw that goes through the control surface. Get in there and put some extra epoxy on the landing gear mounting parts. Use an engine with plenty of power, and add some right thrust to the mounting. DO NOT START OUT WITH LOTS OF THROW! Use a nice conservative low rate, maybe 3/8" elevator and 3/8" aileron, up & down, and dial in some exponential to soften the response. This thing will go real fast and spin or tumble like it's on gimbals, but it's not for beginners.

Good luck,
Dave Olson