Try balancing the plane by picking up the plane with only your index figers (one holding each side of the wing, with the tips of your finders pointing upwards). The plane should balance at about 30% of the wing width, from the leading edge of the wing. If it balances behind this point, add weight to the nose until it does. If it balances in front of this point, add weight to the tail until is does. This should setup your plane for a very slight nose heavy condition, a good starting point.

Now, having said all that, my advice only goes for a traditional glider. If you have a flying wing (Zaggi, etc.) or the wing is tapered backwards (like a jet) then you need to balance the plane at a completely different place.

- Q.