I didn't figure it made a major difference, but you know what they say when you "ASSUME". Since the plane is suspended more like a pendulem, the weight will go under the bob, and the center of gravity is exposed rather than the bob goes to the center of gravity. I have to put these things into perspective before I can understand them..... With the pencil stand, once the cg is marked, it would show tail or nose heavy, and you add weight like on an old scale until it balances closely to where you want it. Nothing fancy, just gets you to where you know where it balances out at.... Thank you for the explaination.