RE: Top Flite 1/7 P-51 Build
If the razor plane is chipping the balsa, it's taking too big of a bite. Loosen the screw and back the blade back into the plane - just a small adjustment, then retighten the screw. Now try it again. Eventually it'll remove long, thin strips of balsa - instead of digging into it. It's a real work saver when it works right.