The calculator you referenced, and others I've seen, do not handle wings with more than one panel. Aside from the Trainers, most of the model aircraft are really 2 or 3 panel airplanes. Treating them as one-panel throws the accuracy of the CG and NP calculations off.

Secondly, the program is extremely user friendly and familiarizes the user with the technology behind the calculations. And, it is fast and accurate if your measurements are taken correctly. When I'm paying $26.00 for a gallon of glow fuel, I consider the CG Optimizer cheap insurance to have the CG and NP located with confidence.<br type="_moz" />