The Combat 40 has a coroplast tail...if you can't get your CG by moving equipment...one of the best ways to ad weight is steel rod in the coroplast flutes of the tail...even helps stiffin it up a bit. BTW Fred, the Lazer 6 is not a computer radio, but does have elevon and v-tail mixing. It's a cool set up (I have one and so does Sassy) but definately not needed on the Kombat 40.