The weight range on the CG Chipmunk is listed as 6-8lbs. If you can actually build it to come out at no more than 6 lbs then an OS .46FX will fly it just fine.

You would need to go with all light-weight components to keep it down to that weight though, such as mini servos on control surfaces, micro for throttle, small RX, small battery, lightweight wheels, etc. You would need to build it for perfect balance with no balast weight front or rear.

It would help if you have some experience building in "lightness". It's a way of thinking as you build where you ask yourself "how can I make this component lighter?" for every piece you put into it. For example, wire pushrods can be replaced with carbon fiber rods, or pull-pull cables. Choose lighter weight colors of covering. Go easy on the glue; this means don't build it with epoxy except where absolutely necessary like firewall and landing gear mounts. Weigh all the wood components and if some pieces are from too hard and heavy stock then replace them with appropriate lighter weight stock. As most of my models are electric powered, it has become second nature for me to become almost fanatical about weight reduction when I build. This practice still carries over when building glow powered.