From Business IT Support:
CG_Calculator is a simple to use centre of gravity (center of lift) calculator for Radio Controlled Model aeroplanes. It estimates the centre of lift for single section wings.
There are several ways to use this free program to workout the approximate location of the CG on you model.
CG is the single most important design aspect of any aircraft. Without this information your aircraft ill be in danger of being uncontrollable. It is always best to run this simple test on you wings before initially flying a newly built or designed plane. The centre of mass of an RC model should be close to the calculated CG.
The author of this software takes no responsibility for the use or resulting effect of the use of this software. "It is not meant for use in the design of manned aircraft".